fix(detail): clamp a backwards DTEND instead of dropping the event (#34)

toEventDetailCore returned null when a present DTEND preceded DTSTART, the
only remaining false-drop that surfaces as the generic "Something went
wrong." error screen — the same un-openable trap as the pre-1970 DTSTART
bug, and worse because the user can't even open the malformed event to fix
it. Clamp the end to DTSTART (a zero-length event) instead, matching how
SearchMapper already coerces its end. After this the detail mapper drops a
row only when DTSTART is genuinely absent (unrenderable).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitea/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,23 @@
+---
+name: Bug report
+about: Something doesn't work the way it should
+title: ""
+labels:
+  - bug
+---
+
+### What happened
+
+
+### What you expected
+
+
+### Steps to reproduce
+1.
+2.
+3.
+
+### Environment
+- Calendula version: <!-- Settings → bottom of the screen -->
+- Android version:
+- Device:

.gitea/ISSUE_TEMPLATE/crash_report.md

@@ -0,0 +1,27 @@
+---
+name: Crash report
+about: Report a crash. Calendula can capture this for you (Settings → Report a problem, or the prompt after a crash) — it copies the report to your clipboard and prefills this form.
+title: "Crash: "
+labels:
+  - bug
+  - crash
+  - priority:high
+---
+
+<!--
+Thanks for reporting a crash in Calendula!
+
+If the app prefilled this for you, the crash report is already below — just add
+what you were doing and submit. Otherwise, paste the report from your clipboard
+into the code block. The report contains only app/Android/device versions and the
+stack trace — no personal data or calendar content.
+-->
+
+### What happened
+
+
+### Crash report
+
+```
+(paste the crash report here)
+```

.gitea/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,16 @@
+---
+name: Feature request
+about: Suggest an idea or improvement
+title: ""
+labels:
+  - feat
+---
+
+### What would you like Calendula to do?
+
+
+### Why — what problem does it solve?
+
+
+### Anything else
+<!-- mockups, examples from other apps, alternatives you considered -->

.gitea/ISSUE_TEMPLATE/question.md

@@ -0,0 +1,19 @@
+---
+name: Question
+about: Ask how something works or get help using Calendula
+title: ""
+labels:
+  - question
+---
+
+### Your question
+
+
+### What you've tried
+<!-- so far, if anything -->
+
+
+### Context
+- Calendula version: <!-- Settings → bottom of the screen -->
+- Android version:
+- Device:

.gitea/workflows/ci.yaml

@@ -1,14 +1,23 @@
 name: CI
 
+# One gate per pull request. Branch pushes no longer trigger CI on their own,
+# so a change is built once on its PR (covering feature -> release/* and
+# release/* -> main) instead of once per push and again on the merge to main.
+# The merge itself is handled by release.yaml, which only does heavy work when
+# the merge actually cuts a release.
 on:
-  push:
-    branches:
-      - '**'
-    tags-ignore:
-      - '**'
   pull_request:
 
+# Cancel superseded runs for the same PR.
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
+  # Single job named `ci` so the required "CI" status check is always reported,
+  # even for docs-only PRs: those just skip the Android build and the job still
+  # succeeds (fast green check) instead of being filtered out and leaving the
+  # required check pending forever.
   ci:
     runs-on: docker
     env:
@@ -17,40 +26,77 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+        with:
+          # Full history so the base..HEAD diff below has a merge-base.
+          fetch-depth: 0
+
+      # Cheap, always-on guard: the release build must stay reproducible for the
+      # official F-Droid repo (no AGP VCS-info embedding). Runs regardless of
+      # change scope so a regression can't slip through on a "docs-only" PR.
+      - name: Reproducible-release invariant
+        run: bash scripts/check_reproducible_release.sh
+
+      # Decide whether anything that affects the app build changed. Docs,
+      # F-Droid metadata and the licence don't, so those PRs skip the SDK +
+      # Gradle work below but still report a green `ci`.
+      - name: Classify change scope
+        id: scope
+        run: |
+          set -e
+          BASE="${{ github.base_ref }}"
+          # Full (not --depth=1) base fetch so the merge-base is present even when
+          # the PR branch forked several commits back; a shallow tip has no merge
+          # base with a divergent branch and `git diff base...HEAD` aborts.
+          git fetch --no-tags origin "$BASE"
+          MB=$(git merge-base "origin/$BASE" HEAD 2>/dev/null || true)
+          if [ -z "$MB" ]; then
+            # No common ancestor available — don't risk skipping the build.
+            echo "No merge base with origin/$BASE — running the full build to be safe."
+            echo "code=true" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+          CHANGED=$(git diff --name-only "$MB" HEAD)
+          echo "Changed files:"; echo "$CHANGED"
+          if echo "$CHANGED" | grep -vE '(\.md$|^docs/|^fdroid-metadata/|^fastlane/|^LICENSE$)' | grep -q .; then
+            echo "code=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "code=false" >> "$GITHUB_OUTPUT"
+            echo "Docs/metadata-only change — skipping the Android build."
+          fi
 
       - name: Setup Java
+        if: steps.scope.outputs.code == 'true'
         uses: actions/setup-java@v4
         with:
           distribution: 'zulu'
           java-version: '17'
 
       - name: Setup Android SDK
+        if: steps.scope.outputs.code == 'true'
         uses: android-actions/setup-android@v3
+        with:
+          # Default ("tools platform-tools") drags in the Android Emulator
+          # (~300 MB) which the build never uses.
+          packages: ''
+
+      - name: Setup Android SDK cache
+        if: steps.scope.outputs.code == 'true'
+        uses: actions/cache@v4
+        with:
+          path: /opt/android-sdk
+          key: ${{ runner.os }}-android-sdk-37-36.0.0
 
       - name: Install Android SDK packages
+        if: steps.scope.outputs.code == 'true'
         run: |
           yes | sdkmanager --licenses >/dev/null || true
           sdkmanager \
             "platform-tools" \
-            "platforms;android-36" \
             "platforms;android-37.0" \
             "build-tools;36.0.0"
 
-      - name: Install jq
-        run: |
-          set -e
-          SUDO=""
-          if command -v sudo >/dev/null 2>&1; then
-            SUDO="sudo"
-          fi
-          if command -v apt-get >/dev/null 2>&1; then
-            $SUDO apt-get update
-            $SUDO apt-get install -y jq
-          elif command -v apk >/dev/null 2>&1; then
-            $SUDO apk add --no-cache jq
-          fi
-
       - name: Setup Gradle cache
+        if: steps.scope.outputs.code == 'true'
         uses: actions/cache@v4
         with:
           path: |
@@ -61,18 +107,25 @@ jobs:
             ${{ runner.os }}-gradle-
 
       - name: Grant execute permission for gradlew
+        if: steps.scope.outputs.code == 'true'
         run: chmod +x ./gradlew
 
+      # No --no-daemon: the daemon lives only as long as this job container
+      # and lets the following steps skip JVM startup + reconfiguration.
       - name: Lint (debug variant only)
-        run: ./gradlew lintDebug --no-daemon
+        if: steps.scope.outputs.code == 'true'
+        run: ./gradlew lintDebug
 
       - name: Unit tests
-        run: ./gradlew testDebugUnitTest --no-daemon
+        if: steps.scope.outputs.code == 'true'
+        run: ./gradlew testDebugUnitTest
 
       - name: Assemble debug APK
-        run: ./gradlew assembleDebug --no-daemon
+        if: steps.scope.outputs.code == 'true'
+        run: ./gradlew assembleDebug
 
       - name: Trivy filesystem scan
+        if: steps.scope.outputs.code == 'true'
         run: |
           set -e
           SUDO=""

.gitea/workflows/release.yaml

@@ -1,17 +1,84 @@
-name: Build and Release to F-Droid
+name: Release — F-Droid repo + Gitea release
 
+# A release is cut by merging a release branch into main with a bumped
+# versionName (see docs/RELEASING.md). This workflow reads that versionName and,
+# if no matching tag exists yet, runs tests, builds + signs the APK, publishes
+# it to the F-Droid repo, and only then creates the vX.Y.Z tag + Gitea release
+# itself — the tag is an output of the pipeline, not its trigger. Ordinary
+# merges (no version bump) fall through `detect` and do nothing.
+#
+# A manual workflow_dispatch (from a branch) runs the re-sign-only recovery
+# path: it re-signs the existing F-Droid index with the repo key and re-uploads,
+# without building an APK or creating a release. Used for key rotation / repo
+# recovery.
 on:
   push:
-    tags:
-      - '*'
+    branches: [main]
   workflow_dispatch:
 
+concurrency:
+  group: release
+  cancel-in-progress: false
+
 jobs:
-  ci:
+  # Cheap gate: resolve the version from the committed build.gradle and decide
+  # whether this push actually cuts a new release (no tag for it yet). Keeps the
+  # heavy job from running on every merge to main.
+  detect:
+    runs-on: docker
+    outputs:
+      is_release: ${{ steps.v.outputs.is_release }}
+      version: ${{ steps.v.outputs.version }}
+      version_code: ${{ steps.v.outputs.version_code }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Resolve version and whether it is a new release
+        id: v
+        env:
+          TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          API: ${{ github.server_url }}/api/v1/repos/${{ github.repository }}
+        run: |
+          set -e
+          VERSION=$(grep -oP 'versionName\s*=\s*"\K[^"]+' app/build.gradle.kts)
+          if [ -z "$VERSION" ]; then echo "No versionName in app/build.gradle.kts" >&2; exit 1; fi
+          MAJOR=$(echo "$VERSION" | cut -d. -f1); MINOR=$(echo "$VERSION" | cut -d. -f2); PATCH=$(echo "$VERSION" | cut -d. -f3)
+          MAJOR=${MAJOR:-0}; MINOR=${MINOR:-0}; PATCH=${PATCH:-0}
+          VERSION_CODE=$(( MAJOR * 10000 + MINOR * 100 + PATCH ))
+          echo "version=$VERSION" >> "$GITHUB_OUTPUT"
+          echo "version_code=$VERSION_CODE" >> "$GITHUB_OUTPUT"
+          echo "Resolved version $VERSION (code $VERSION_CODE)"
+          if [ "${{ github.event_name }}" = "workflow_dispatch" ]; then
+            echo "Manual dispatch — re-sign path, not a release."
+            echo "is_release=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+          # A tag for this version already existing means the release shipped on
+          # an earlier push; do nothing. Absent => this merge cuts the release.
+          STATUS=$(curl -s -o /dev/null -w '%{http_code}' \
+            -H "Authorization: token $TOKEN" "$API/git/refs/tags/v$VERSION")
+          if [ "$STATUS" = "200" ]; then
+            echo "Tag v$VERSION already exists — nothing to release."
+            echo "is_release=false" >> "$GITHUB_OUTPUT"
+          else
+            echo "No tag for v$VERSION yet — cutting the release."
+            echo "is_release=true" >> "$GITHUB_OUTPUT"
+          fi
+
+  # Releases: build + sign + publish, then mint the tag and Gitea release.
+  # Also runs on manual dispatch, where it skips the build and just re-signs and
+  # re-uploads the existing index (recovery path).
+  release:
+    needs: detect
+    if: needs.detect.outputs.is_release == 'true' || github.event_name == 'workflow_dispatch'
     runs-on: docker
     env:
       ANDROID_HOME: /opt/android-sdk
       ANDROID_SDK_ROOT: /opt/android-sdk
+      VERSION: ${{ needs.detect.outputs.version }}
+      VERSION_CODE: ${{ needs.detect.outputs.version_code }}
+      IS_RELEASE: ${{ needs.detect.outputs.is_release }}
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -24,57 +91,33 @@ jobs:
 
       - name: Setup Android SDK
         uses: android-actions/setup-android@v3
-
-      - name: Install Android SDK packages
-        run: |
-          yes | sdkmanager --licenses >/dev/null || true
-          sdkmanager \
-            "platform-tools" \
-            "platforms;android-36" \
-            "platforms;android-37.0" \
-            "build-tools;36.0.0"
-
-      - name: Grant execute permission for gradlew
-        run: chmod +x ./gradlew
-
-      # Lint already enforced on every push to main via ci.yaml.
-      # Release sanity only re-runs tests + a debug build to catch
-      # any tag-resolved drift (e.g. version code substitution issues).
-
-      - name: Unit tests
-        run: ./gradlew testDebugUnitTest --no-daemon
-
-      - name: Assemble debug APK (sanity)
-        run: ./gradlew assembleDebug --no-daemon
-
-  build-and-deploy:
-    needs: ci
-    runs-on: docker
-    env:
-      ANDROID_HOME: /opt/android-sdk
-      ANDROID_SDK_ROOT: /opt/android-sdk
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-
-      - name: Setup Java
-        uses: actions/setup-java@v4
         with:
-          distribution: 'zulu'
-          java-version: '17'
+          packages: ''
 
-      - name: Setup Android SDK
-        uses: android-actions/setup-android@v3
+      - name: Setup Android SDK cache
+        uses: actions/cache@v4
+        with:
+          path: /opt/android-sdk
+          key: ${{ runner.os }}-android-sdk-37-36.0.0
 
       - name: Install Android SDK packages
         run: |
           yes | sdkmanager --licenses >/dev/null || true
           sdkmanager \
             "platform-tools" \
-            "platforms;android-36" \
             "platforms;android-37.0" \
             "build-tools;36.0.0"
 
+      - name: Setup Gradle cache
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties', 'gradle/libs.versions.toml') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+
       - name: Install jq
         run: |
           set -e
@@ -87,22 +130,26 @@ jobs:
             $SUDO apk add --no-cache jq
           fi
 
-      - name: Set version from git tag
+      - name: Grant execute permission for gradlew
+        run: chmod +x ./gradlew
+
+      # The committed versionName is the source of truth. Pin versionCode to the
+      # value derived from it so the published APK's code is always
+      # MAJOR*10000 + MINOR*100 + PATCH even if the committed code was forgotten.
+      - name: Pin versionCode to versionName
+        if: env.IS_RELEASE == 'true'
         run: |
           set -e
-          RAW_TAG="${GITHUB_REF_NAME:-${GITHUB_REF##*/}}"
-          VERSION="${RAW_TAG#v}"
-          MAJOR=$(echo "$VERSION" | cut -d. -f1)
-          MINOR=$(echo "$VERSION" | cut -d. -f2)
-          PATCH=$(echo "$VERSION" | cut -d. -f3)
-          MAJOR=${MAJOR:-0}; MINOR=${MINOR:-0}; PATCH=${PATCH:-0}
-          VERSION_CODE=$(( MAJOR * 10000 + MINOR * 100 + PATCH ))
-          echo "Version: $VERSION, VersionCode: $VERSION_CODE"
-          sed -i "s/versionName = \".*\"/versionName = \"$VERSION\"/" app/build.gradle.kts
           sed -i "s/versionCode = .*/versionCode = $VERSION_CODE/" app/build.gradle.kts
           grep -E 'versionName|versionCode' app/build.gradle.kts
 
+      # Test the exact commit being shipped (only on a real release).
+      - name: Unit tests
+        if: env.IS_RELEASE == 'true'
+        run: ./gradlew testDebugUnitTest
+
       - name: Setup Android Keystore
+        if: env.IS_RELEASE == 'true'
         env:
           KEYSTORE_BASE64: ${{ secrets.KEYSTORE_BASE64 }}
           KEY_PASSWORD: ${{ secrets.KEY_PASSWORD }}
@@ -117,11 +164,9 @@ jobs:
           storeFile=upload-keystore.jks
           EOF
 
-      - name: Grant execute permission for gradlew
-        run: chmod +x ./gradlew
-
       - name: Build release APK
-        run: ./gradlew assembleRelease --no-daemon
+        if: env.IS_RELEASE == 'true'
+        run: ./gradlew assembleRelease
 
       - name: Setup F-Droid Server Tools
         run: |
@@ -131,50 +176,80 @@ jobs:
           $SUDO apt-get install -y sshpass python3-pip
           pip3 install --break-system-packages --upgrade fdroidserver
 
-      - name: Initialize or fetch F-Droid Repository
+      - name: Fetch existing F-Droid repo from Hetzner
         env:
           HOST: ${{ secrets.HETZNER_HOST }}
           USER: ${{ secrets.HETZNER_USER }}
           PASS: ${{ secrets.HETZNER_PASS }}
         run: |
+          set -euo pipefail
+          SSH_OPTS="-o StrictHostKeyChecking=no -o ConnectTimeout=20"
           mkdir -p fdroid
-          sshpass -p "$PASS" sftp -o StrictHostKeyChecking=no "$USER@$HOST" <<'SFTP'
-          -mkdir dev
-          -mkdir dev/fdroid
-          -mkdir dev/fdroid/repo
-          SFTP
-          sshpass -p "$PASS" scp -o StrictHostKeyChecking=no -r "$USER@$HOST:dev/fdroid/." fdroid/ || (cd fdroid && fdroid init)
+          # Pull only the published repo/ (all apps' APKs), any per-app
+          # metadata, and the repo icon — enough to rebuild the index without
+          # dropping the other apps. The signing key is deliberately NOT pulled
+          # from the box; it comes from CI secrets in the next step so it never
+          # has to live in the web-served tree.
+          sshpass -p "$PASS" scp $SSH_OPTS -r "$USER@$HOST:dev/fdroid/repo" fdroid/ 2>/dev/null || true
+          sshpass -p "$PASS" scp $SSH_OPTS -r "$USER@$HOST:dev/fdroid/metadata" fdroid/ 2>/dev/null || true
+          sshpass -p "$PASS" scp $SSH_OPTS "$USER@$HOST:dev/fdroid/icon.png" fdroid/ 2>/dev/null || true
+          mkdir -p fdroid/repo fdroid/metadata
 
-      - name: Ensure F-Droid repo signing key and icon
+      - name: Restore F-Droid signing key and config from secrets
+        env:
+          FDROID_KEYSTORE_BASE64: ${{ secrets.FDROID_KEYSTORE_BASE64 }}
+          FDROID_CONFIG_BASE64: ${{ secrets.FDROID_CONFIG_BASE64 }}
         run: |
-          cd fdroid
-          mkdir -p repo/icons
-          if [ ! -f keystore.p12 ]; then
-            fdroid update --create-key
+          set -euo pipefail
+          # Fail loudly if the repo key is not configured. NEVER auto-generate
+          # one: a fresh key changes the repo fingerprint and breaks every
+          # user's pinned repo.
+          if [ -z "${FDROID_KEYSTORE_BASE64:-}" ] || [ -z "${FDROID_CONFIG_BASE64:-}" ]; then
+            echo "ERROR: FDROID_KEYSTORE_BASE64 / FDROID_CONFIG_BASE64 secrets are not set." >&2
+            echo "Refusing to continue — will not auto-generate a new repo key." >&2
+            exit 1
           fi
+          echo "$FDROID_KEYSTORE_BASE64" | base64 --decode > fdroid/keystore.p12
+          echo "$FDROID_CONFIG_BASE64"   | base64 --decode > fdroid/config.yml
+          test -s fdroid/keystore.p12
+          test -s fdroid/config.yml
+          mkdir -p fdroid/repo/icons
 
       - name: Copy new APK to repo
+        if: env.IS_RELEASE == 'true'
         run: |
           set -e
           mkdir -p fdroid/repo
-          REF_NAME="${GITHUB_REF_NAME:-${GITHUB_REF##*/}}"
-          SAFE_REF_NAME="$(echo "$REF_NAME" | tr '/ ' '__' | tr -cd '[:alnum:]_.-')"
-          if [ -z "$SAFE_REF_NAME" ]; then
-            SAFE_REF_NAME="${GITHUB_SHA:-manual}"
-          fi
-          cp app/build/outputs/apk/release/app-release.apk "fdroid/repo/calendula_${SAFE_REF_NAME}.apk"
+          cp app/build/outputs/apk/release/app-release.apk "fdroid/repo/calendula_v${VERSION}.apk"
 
-      - name: Copy metadata to F-Droid repo
+      # Per-version "What's New": ensure this version's changelog exists in the
+      # fastlane tree (committed at release-cut time for the official repo; this
+      # regenerates it from CHANGELOG.md so the self-hosted repo never depends on
+      # the commit having happened). The transform below then carries it across.
+      - name: Ensure this version's changelog is in the fastlane tree
+        if: env.IS_RELEASE == 'true'
+        run: bash scripts/sync_changelog_to_fastlane.sh
+
+      - name: Build F-Droid metadata from fastlane (single source of truth)
         run: |
           mkdir -p fdroid/metadata
-          cp -r fdroid-metadata/* fdroid/metadata/
+          # App-level control file (Categories/License/links) for the self-hosted
+          # repo's `fdroid update`.
+          cp fdroid-metadata/de.jeanlucmakiola.calendula.yml fdroid/metadata/
+          # Localized text + graphics + per-version changelogs come from the SAME
+          # fastlane tree the official F-Droid repo harvests from source,
+          # transformed into the F-Droid repo "localized" layout. One source of
+          # truth, both channels.
+          bash scripts/fastlane_to_fdroid_localized.sh \
+            fastlane/metadata/android \
+            fdroid/metadata/de.jeanlucmakiola.calendula
 
       - name: Generate F-Droid Index
         run: |
           cd fdroid
           fdroid update -c
 
-      - name: Upload Repo to Hetzner
+      - name: Upload repo/ to Hetzner
         env:
           HOST: ${{ secrets.HETZNER_HOST }}
           USER: ${{ secrets.HETZNER_USER }}
@@ -185,6 +260,89 @@ jobs:
           sshpass -p "$PASS" sftp $SSH_OPTS "$USER@$HOST" <<'SFTP'
           -mkdir dev
           -mkdir dev/fdroid
-          -mkdir dev/fdroid/repo
           SFTP
-          sshpass -p "$PASS" scp $SSH_OPTS -r fdroid/. "$USER@$HOST:dev/fdroid/"
+          # Publish the signed repo/ plus metadata/ (descriptions, screenshots,
+          # per-version changelogs) so changelog history survives across
+          # releases. keystore.p12 and config.yml are NEVER uploaded.
+          sshpass -p "$PASS" scp $SSH_OPTS -r fdroid/repo fdroid/metadata "$USER@$HOST:dev/fdroid/"
+
+      # The APK is published and the index re-signed — now record the release.
+      # Creating it with target_commitish makes Gitea create the vX.Y.Z tag at
+      # this commit, so the tag only ever marks a fully-shipped release (and a
+      # failure before here leaves no tag, so re-running the workflow retries).
+      - name: Create tag + Gitea release
+        if: env.IS_RELEASE == 'true'
+        env:
+          TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          API: ${{ github.server_url }}/api/v1/repos/${{ github.repository }}
+          SHA: ${{ github.sha }}
+        run: |
+          set -e
+          TAG="v$VERSION"
+          # Notes = this version's CHANGELOG section.
+          awk -v ver="$VERSION" '
+            $0 ~ "^## \\[" ver "\\]" { flag = 1; next }
+            /^## \[/ { flag = 0 }
+            flag' CHANGELOG.md > release-notes.md
+          sed -i -e '/./,$!d' release-notes.md
+          if [ ! -s release-notes.md ]; then
+            echo "_No changelog entry for ${VERSION} — see CHANGELOG.md._" > release-notes.md
+          fi
+          python3 - "$TAG" "$SHA" <<'PY' > payload.json
+          import json, sys
+          print(json.dumps({
+              "tag_name": sys.argv[1],
+              "target_commitish": sys.argv[2],
+              "name": sys.argv[1],
+              "body": open("release-notes.md").read(),
+              "draft": False,
+              "prerelease": False,
+          }))
+          PY
+          # Upsert (re-run safe): PATCH if a release for the tag already exists,
+          # else POST a new one (which also creates the tag at target_commitish).
+          curl -s -H "Authorization: token $TOKEN" "$API/releases/tags/$TAG" > existing.json
+          ID=$(jq -r '.id // empty' existing.json 2>/dev/null || true)
+          if [ -n "$ID" ]; then
+            CODE=$(curl -s -o response.json -w '%{http_code}' -X PATCH \
+              -H "Authorization: token $TOKEN" -H "Content-Type: application/json" \
+              -d @payload.json "$API/releases/$ID")
+            OK=200
+          else
+            CODE=$(curl -s -o response.json -w '%{http_code}' -X POST \
+              -H "Authorization: token $TOKEN" -H "Content-Type: application/json" \
+              -d @payload.json "$API/releases")
+            OK=201
+          fi
+          cat response.json
+          if [ "$CODE" != "$OK" ]; then
+            echo "Release upsert failed with HTTP $CODE (expected $OK)" >&2
+            exit 1
+          fi
+          echo "Created/updated release $TAG at $SHA"
+
+      # Archive the R8 mapping so user crash stacktraces stay deobfuscatable.
+      # Attached to the release (it's not an APK, so it fits the no-binaries
+      # rule). Best-effort: never fail a release over it.
+      - name: Attach R8 mapping to Gitea release
+        if: env.IS_RELEASE == 'true'
+        continue-on-error: true
+        env:
+          TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          API: ${{ github.server_url }}/api/v1/repos/${{ github.repository }}
+        run: |
+          set -e
+          MAP="app/build/outputs/mapping/release/mapping.txt"
+          if [ ! -f "$MAP" ]; then echo "No mapping.txt (R8 off?) — skipping."; exit 0; fi
+          TAG="v$VERSION"
+          ASSET="mapping-${VERSION}.txt.gz"
+          gzip -c "$MAP" > "/tmp/$ASSET"
+          ID=$(curl -s -H "Authorization: token $TOKEN" "$API/releases/tags/$TAG" | jq -r '.id // empty')
+          if [ -z "$ID" ]; then echo "Could not resolve release id — skipping."; exit 0; fi
+          # Replace any prior asset of the same name (re-run safe).
+          OLD=$(curl -s -H "Authorization: token $TOKEN" "$API/releases/$ID/assets" \
+            | jq -r --arg n "$ASSET" '.[] | select(.name==$n) | .id')
+          [ -n "$OLD" ] && curl -s -X DELETE -H "Authorization: token $TOKEN" "$API/releases/$ID/assets/$OLD" >/dev/null || true
+          curl -s -X POST -H "Authorization: token $TOKEN" \
+            -F "attachment=@/tmp/$ASSET" \
+            "$API/releases/$ID/assets?name=$ASSET" -o /dev/null -w "asset upload HTTP %{http_code}\n"

.gitea/workflows/renovate.yml

@@ -0,0 +1,42 @@
+name: Renovate
+
+on:
+  # Weekly sweep. Mondays 05:00 UTC — this cron owns the cadence; the repo's
+  # renovate.json5 deliberately has no internal schedule (avoids double-gating).
+  schedule:
+    - cron: '0 5 * * 1'
+  # Manual run for an on-demand sweep from the Actions tab.
+  workflow_dispatch:
+
+# Never let two Renovate runs touch the repo at once.
+concurrency:
+  group: renovate
+  cancel-in-progress: false
+
+jobs:
+  renovate:
+    runs-on: docker
+    # Run the Renovate image *as* the job container and invoke the `renovate`
+    # binary directly. The renovatebot/github-action wrapper is a thin Node
+    # action that shells out to `docker run …` — it needs a Docker CLI + socket
+    # inside the job, which the Gitea runner's plain node container has not, so
+    # it died on "Unable to locate executable file: docker". Running the image
+    # directly drops the docker-in-docker requirement entirely.
+    # Full tag pinned; Renovate's github-actions manager keeps it bumped.
+    container:
+      image: ghcr.io/renovatebot/renovate:43.232.0
+    steps:
+      - name: Run Renovate
+        run: renovate
+        env:
+          # Self-hosted Gitea, not github.com.
+          RENOVATE_PLATFORM: gitea
+          RENOVATE_ENDPOINT: https://gitea.jeanlucmakiola.de/api/v1
+          # Bot-account token (Gitea secret). Needs repo read/write + PR scope.
+          RENOVATE_TOKEN: ${{ secrets.RENOVATE_TOKEN }}
+          # Scope to this repo only — no org-wide autodiscovery.
+          RENOVATE_AUTODISCOVER: 'false'
+          RENOVATE_REPOSITORIES: '["makiolaj/calendula"]'
+          # Commits/PRs authored as the bot, not a real maintainer.
+          RENOVATE_GIT_AUTHOR: 'Renovate Bot <renovate@jeanlucmakiola.de>'
+          LOG_LEVEL: info

.gitea/workflows/translations.yaml

@@ -0,0 +1,37 @@
+name: Translations
+
+# Fast, SDK-free parity check for translation resources, so Weblate PRs (which
+# only touch values-*/strings.xml) get quick feedback without the full Android
+# build. The deeper checks still run in CI via lintDebug (ExtraTranslation).
+on:
+  pull_request:
+    paths:
+      - 'app/src/main/res/values*/strings.xml'
+      - 'app/src/main/res/xml/locales_config.xml'
+      - 'scripts/check_translations.py'
+      - '.gitea/workflows/translations.yaml'
+
+concurrency:
+  group: translations-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  check:
+    runs-on: docker
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Ensure python3
+        run: |
+          if ! command -v python3 >/dev/null 2>&1; then
+            if command -v apt-get >/dev/null 2>&1; then
+              apt-get update && apt-get install -y python3
+            elif command -v apk >/dev/null 2>&1; then
+              apk add --no-cache python3
+            fi
+          fi
+          python3 --version
+
+      - name: Check translation parity
+        run: python3 scripts/check_translations.py

.gitignore

@@ -40,6 +40,7 @@ captures/
 # Keystore files
 *.jks
 *.keystore
+*.p12
 /key.properties
 
 # Google Services (e.g. APIs or Firebase)
@@ -50,8 +51,7 @@ google-services.json
 Thumbs.db
 
 # F-Droid local artifacts (the pipeline generates them in CI)
-fdroid/repo/
-fdroid/keystore.p12
+/fdroid/
 
 # KSP
 .ksp/

.planning/PROJECT.md

@@ -2,11 +2,12 @@
 
 ## What This Is
 
-A modern Material 3 Expressive Android calendar app, read-only V1. Lives
-entirely on top of Android's `CalendarContract` — any calendar synced to the
-device (CalDAV via DAVx5, Google, local, WebCal, …) shows up automatically.
-The differentiator is visual: real Material 3 Expressive design that no
-existing FOSS calendar app delivers.
+A modern Material 3 Expressive Android calendar app. Lives entirely on top
+of Android's `CalendarContract` — any calendar synced to the device (CalDAV
+via DAVx5, Google, local, WebCal, …) shows up automatically; creating,
+editing, and deleting writes straight back, and reminders are delivered by
+the app itself (Etar model). The differentiator is visual: real Material 3
+Expressive design that no existing FOSS calendar app delivers.
 
 ## Core Value
 
@@ -15,8 +16,10 @@ re-inventing the calendar sync stack — leave that to DAVx5 and the system.
 
 ## Current Milestone
 
-**v0.1 — Foundation & CI:** Buildable Android project scaffold with theme,
-icon, i18n, Hilt, DataStore, green CI.
+Milestones 1 (read, v1.0) and 2 (write support, v1.1–v2.0.0 incl. reminder
+delivery) are **complete** — v2.0.0 shipped 2026-06-11. Next is v3.0
+(power-user features) plus an undecided "Locations & People" idea backlog;
+see `ROADMAP.md`.
 
 ## Stack
 
@@ -26,9 +29,8 @@ Expressive 1.5.0-alpha21 (alpha is intentional — Expressive APIs only
 live in the 1.5 alpha line). Hilt 2.59.2, DataStore. Gradle Kotlin DSL
 with Version Catalog. AGP 9.1.1, Gradle 9.5.1. JVM target 17.
 
-Read-only V1, write support V2.
-
-Android-only (minSdk 29, targetSdk 36). No iOS.
+Android-only (minSdk 29, targetSdk 36). No iOS. No `INTERNET` permission —
+any feature that would need one is an explicit product decision first.
 
 ## Naming
 

.planning/REQUIREMENTS.md

@@ -2,36 +2,43 @@
 
 See full design spec: `docs/superpowers/specs/2026-06-08-calendar-app-design.md`
 
-## V1 Scope (Variant "B")
+## V1 Scope (Variant "B") — shipped in full (v1.0.0, 2026-06-11)
 
-### Validated (shipped)
-- Foundation & CI infrastructure — v0.1.0 (2026-06-08)
-
-### Active (V1)
-
-- [x] Foundation & CI infrastructure
+- [x] Foundation & CI infrastructure — v0.1.0 (2026-06-08)
 - [x] Data Layer over `CalendarContract`
 - [x] Permission flow (`READ_CALENDAR`)
-- [ ] Month view (S1)
-- [ ] Week view (S2)
-- [ ] Day view (S3)
-- [ ] Event Detail Sheet (S4)
-- [ ] Multi-Calendar Filter (M3)
-- [ ] Today button + Jump-to-Date (M2)
-- [ ] View-Switcher (M1)
-- [ ] Settings screen (M4)
-- [ ] Empty / no-permission / no-calendars states
-- [ ] German + English localization
-- [ ] Loading/Failure/Success states per screen (architectural pattern)
+- [x] Month view (S1)
+- [x] Week view (S2)
+- [x] Day view (S3)
+- [x] Event Detail Sheet (S4) — became a full screen, plus full event read (v0.6)
+- [x] Multi-Calendar Filter (M3)
+- [x] Today button (M2) — shipped v0.5; Jump-to-Date **cut from scope**
+- [x] View-Switcher (M1)
+- [x] Settings screen (M4)
+- [x] Empty / no-permission / no-calendars states
+- [x] German + English localization
+- [x] Loading/Failure/Success states per screen (architectural pattern)
 
-### Out of Scope (V2+)
+## V2 Scope — write support, shipped in full (v2.0.0, 2026-06-11)
+
+- [x] Write foundation: `WRITE_CALENDAR`, read-only-calendar detection, delete (v1.1)
+- [x] Create event: form, FAB, last-used calendar (v1.2; polish v1.2.1)
+- [x] Edit event: shared form, scoped recurring writes, recurrence picker (v1.3)
+- [x] Reminder notifications (v1.4) — **reversal of the original
+  "system handles reminders" assumption:** Calendula targets
+  sole-calendar-app users, so it posts reminder notifications itself
+  (Etar model), incl. `POST_NOTIFICATIONS` onboarding
+- [x] Conflict dialog on save + store polish (v2.0)
+- Quick-add — **cut from scope** (the prefilled form covers it)
+- Calendar switching while editing — moved to v3 backlog
+
+### Out of Scope (V3+)
 
-- Event create / edit / delete (V2)
 - Home-screen widget
 - Full-text search
-- Quick-add
-- Custom notifications/reminders (system already handles these)
 - Tablet/foldable-specific layouts
+- Locations & People ideas (contact picker, OSM autocomplete) — see
+  `ROADMAP.md` idea backlog, undecided
 - iOS support (Android-only by design)
 
 ## Constraints

.planning/ROADMAP.md

@@ -6,27 +6,582 @@
 |---|---|---|
 | v0.1 | Foundation & CI | complete |
 | v0.2 | Data Layer & Permission Flow | complete |
-| v0.3 | Month view | pending |
-| v0.4 | Week view | pending |
-| v0.5 | Day view | pending |
-| v0.6 | Event Detail Sheet | pending |
-| v0.7 | Filter & Settings | pending |
+| v0.3 | Month + Week + Day views, view switcher | complete |
+| v0.4 | Event Detail (S4) + humanized recurrence | complete |
+| v0.5 | Calendar filter (M3) + Settings (M4) | complete |
+| v0.6 | Full event read — surface every readable field | complete |
+| v1.0 | First public release — polish pass, F-Droid | complete |
 
-## v1.0 — First Public Release
+Delivery ran ahead of the original table: Day view (S3) shipped in v0.3 and
+Event Detail (S4) in v0.4, so the Filter/Settings milestone became v0.5.
 
-All V1 features shipped, polished, on F-Droid. Read-only calendar.
+Jump-to-date (the date-picker half of M2) was **cut from scope** and will not
+ship. The "Today" half of M2 already shipped in v0.5 (drawer entry).
 
-## v2.0 — Write Support
+## v0.6 — Full event read
 
-- Event create / edit / delete via `CalendarContract` writes
-- Quick-add sheet
-- Conflict UX (event modified externally during edit)
+Round out the read-only model so a detail view shows everything the system
+actually stores, before write support starts. Scope = `CalendarContract`
+columns we don't yet read/display:
 
-## v3.0 — Power-User Features
+- **Reminders** (`VALARM`) — read `CalendarContract.Reminders`, list lead times
+- **Status** — Confirmed / Tentative / Cancelled (cancelled shown struck-through)
+- **Availability** (`TRANSP`) — Free / Busy chip
+- **Attendee extras** — role (required / optional / organizer) + the user's own
+  `SELF_ATTENDEE_STATUS`
+- **Timezone** (`EVENT_TIMEZONE`) — shown only when it differs from the device zone
+- **URL** — ~~tappable link card~~ **cut**: `CalendarContract` exposes no
+  `Events.URL` column (only `CUSTOM_APP_URI`, an originating-app deep-link).
+  URLs are instead surfaced by linkifying the description text
+- **Access level / class** (private / confidential) — small chip (optional, trivial)
 
-- Home-screen widget
-- Full-text search
-- Tablet / foldable layouts
-- Optional: ICS file import (drag-and-drop)
+All of the above shipped in v0.6.0 (2026-06-11).
 
-Order is indicative — community feedback after V1 may re-prioritize.
+Deliberately out of v0.6:
+- Recurrence exception / modified-occurrence badges — `Instances` already
+  resolves correct per-occurrence times for display; this only matters for
+  editing, so it folds into v2
+- `CATEGORIES`, `ATTACH` — not reliably exposed by `CalendarContract`
+  (provider limitation, not our choice)
+
+## v1.0 — First Public Release — shipped 2026-06-11
+
+All V1 features shipped, polished, on F-Droid. Read-only calendar. Cut directly
+after v0.6 (full event read) plus the onboarding-screen polish pass.
+
+### Polish backlog (pre-1.0)
+- ~~Redesign the initial grant-access (permission) screen~~ — **done**
+  (Material 3 Expressive onboarding, shipped in v0.6.0 / v1.0.0)
+
+## v2.0 — Write Support (complete, shipped 2026-06-11)
+
+Delivered in four releasable slices (plan:
+`docs/superpowers/plans/2026-06-11-03-write-support.md`). The V1 spec is a
+guide here, not a contract — scope per slice is decided as we go.
+
+| Version | Milestone | Status |
+|---|---|---|
+| v1.1 | Write foundation — `WRITE_CALENDAR`, read-only-calendar detection, delete (series + single occurrence) | complete (shipped 2026-06-11) |
+| v1.2 | Create event — form, FAB, last-used-calendar preselect | complete (shipped 2026-06-11) |
+| v1.2.1 | Form polish after on-device review — card design system, optional fields + settings defaults, OptionCard dialogs, expressive motion | complete (shipped 2026-06-11) |
+| v1.3 | Edit event — shared form, scoped recurring writes (this / following / all), recurrence picker | complete (shipped 2026-06-11) |
+| v1.4 | Reminder notifications — see below | complete (shipped 2026-06-11) |
+| v2.0 | Conflict dialog, polish pass (store copy refresh, F-Droid screenshots), release | complete (shipped 2026-06-11) |
+
+v2.0 scope was re-cut on 2026-06-11, after v1.4:
+- **Occurrence edit** already shipped early, in v1.3.
+- **Quick-add** is **cut from scope**: the full form already opens prefilled
+  (visible day, last-used calendar, optional fields hidden), so the sheet
+  would only save one screen transition while adding a second create-surface
+  to maintain. Revisit only if real-world feedback says creation feels heavy.
+- **Calendar switching while editing** moves to the v3 backlog (sync-adapter
+  minefield: `CALENDAR_ID` is sync-adapter-owned, AOSP locks the field; an
+  honest implementation is copy+delete like Google Calendar, with sync-identity
+  and attendee side effects).
+- **Conflict dialog** stays (plan 03, decision 5): on save, compare against
+  the row as it was when the form loaded; on external change, ask
+  overwrite / discard. Closes the silent-clobber gap on synced calendars.
+
+## v1.4 — Reminder Notifications
+
+**Essential**, not nice-to-have: Calendula targets users for whom it is their
+*only* calendar app, so reminder delivery can't be delegated to Google/OEM
+Calendar. The calendar provider schedules reminders and broadcasts
+`android.intent.action.EVENT_REMINDER`, but it does **not** post the visible
+notification — a calendar app must. We become that app (the Etar model).
+
+Scope:
+- Manifest-registered `BroadcastReceiver` for `EVENT_REMINDER`
+  (data scheme `content://com.android.calendar`) — wakes us at reminder time,
+  no foreground service.
+- Read `CalendarContract.CalendarAlerts` / `Reminders`, filter to
+  `METHOD_ALERT` / `METHOD_DEFAULT` (skip `METHOD_EMAIL`); post on a dedicated
+  notification channel; tap opens event detail.
+- `POST_NOTIFICATIONS` runtime permission (API 33+) — requested in onboarding.
+- Onboarding step: (a) request `POST_NOTIFICATIONS`, (b) in-app reminders
+  toggle, **default ON**, with copy warning that a second calendar app with
+  notifications on will cause duplicate reminders. Mirrored into Settings
+  (reversible).
+
+Deliberately deferred (add only if needed):
+- Snooze / dismiss notification actions (Etar has them)
+- Battery-optimization exemption prompt for delivery reliability
+
+## v2.1 — Month event grid + drawer view tabs (shipped 2026-06-15)
+
+- Month grid shows real events as continuous multi-day bars (not just dots)
+- View section in the navigation drawer to switch Month / Week / Day
+- Fix: text cursor no longer jumps in event text fields
+
+## v2.2 — Tap-to-create + local calendar management (shipped 2026-06-16)
+
+- Tap an empty slot in day/week → create form prefilled with that day + the
+  tapped hour (snapped to the hour, 1 h long)
+- Local (device-only) calendar management in a full-screen editor from
+  Settings → Calendars: create / rename / recolor / delete, with name,
+  pastel-previewed colour, and description (stored in `CAL_SYNC1`)
+- Synced calendars listed read-only, grouped by account, each with a
+  per-account "manage in source app" deep-link (resolved from the account's
+  authenticator — DAVx5/ICSx5/…) + an add-account shortcut
+- Shared `InlineTextField` extracted to `ui.common` (event form + calendar
+  editor share one input style)
+
+## v2.3 — Material 3 grouped-list redesign (shipped 2026-06-16)
+
+A structural + visual pass adopting one shared blueprint (modelled on the ReFra
+gallery app) across Settings, the calendar manager and the navigation drawer.
+
+- Shared `ui/common/GroupedList.kt`: `CollapsingScaffold` (a `LargeTopAppBar`
+  whose title collapses on scroll) + `GroupedRow` (Position-based corner
+  grouping, press-animated corners, `selected` + `minHeight` knobs).
+- Settings: category hub with About card on top and sliding sub-pages
+  (Appearance / New event form / Notifications); theme/week-start/language
+  pickers moved from `DropdownMenu` to OptionCard dialogs; token-based icon
+  chips; `ic_gitea.xml` for the About "Source" button.
+- Calendar manager + drawer restyled to match; shared `CalendarColorChip`;
+  drawer scrolls as one with the active view highlighted.
+- Cards use `surfaceContainerHigh` for readable contrast.
+- Donate button on the About card deferred (target TBD).
+
+---
+
+# Backlog (theme-based, post-v2.1)
+
+The old v3.0 / "daily-driver polish" / "Locations & People" lists are
+consolidated here by theme. Within a group, **(in progress)** /
+**(next)** mark what is being or about to be worked; everything else is an
+approved-but-unscheduled idea unless tagged **(idea)** /
+**(go/no-go)** / **(rejected)**. Order across groups is not a commitment.
+
+## Near-term sequence (ranked, 2026-06-16)
+
+The theme groups below are the full menu; this is the committed *order* for
+the next stretch. Ranking favours finishing the current create/edit + calendar
+arc before opening new fronts, then cheap-relative-to-value items and ones that
+unblock a later item. Order is a plan, not a contract — revisit after each lands.
+
+**Tier 1 — finish the current arc (create/edit + calendars)**
+1. Tap-to-create in day/week *(shipped v2.2.0)* — prefilled create from an empty slot
+2. Local calendar management + "manage in source app" deep-links *(shipped v2.2.0)*
+3. ~~Settings redesign & restructure~~ *(shipped v2.3.0 — grew into the full
+   grouped-list blueprint across Settings + calendars + drawer; see "v2.3"
+   above)*
+4. ~~Per-event color~~ *(shipped v2.4.0)* — palette calendars write
+   `EVENT_COLOR_KEY` (sync-safe); local/opted-in calendars write a raw
+   `EVENT_COLOR`; off-by-default setting for no-palette synced calendars
+Tier 1's create/edit + calendars arc is effectively closed. **Duplicate event**
+was deprioritised (2026-06-17) as low-importance and dropped to the bottom of
+the sequence; the next item is now **Jump-to-date** (formerly Tier 2).
+
+(Tier 2+ numbering below shifts accordingly; ranking unchanged.)
+
+### Settings redesign & restructure *(shipped v2.3.0)*
+
+The original scope below is kept as a record; the implementation expanded from a
+sub-screen restructure into the shared grouped-list blueprint (see "v2.3" above).
+
+The settings screen has grown into a flat vertical scroll of divider-separated
+sections (Appearance, Event form, Notifications, Calendars, Language, About) and
+will keep accreting rows (per-event-color defaults, default reminder, more
+calendar entries are all queued). It needs structure before it gets unwieldy.
+
+**Decided (2026-06-16): sub-screens**, not flat-but-carded. The top level
+becomes a category list; each category opens its own destination. More
+M3-idiomatic for a settings surface that will keep growing, and it mirrors the
+existing Calendars row, which already navigates out to its own screen.
+
+Structure — top-level settings list → category destinations:
+- **Appearance** → theme, dynamic colour, week start
+- **Event form** → the 6 default-field toggles + the hint text
+- **Notifications** → reminders toggle (POST_NOTIFICATIONS flow stays)
+- **Calendars** → already its own screen (`CalendarsScreen`); just becomes a
+  peer category row, no change to that screen
+- **Language** → single control; keep as a top-level row that opens an
+  OptionCard directly (a whole sub-screen for one choice is overkill)
+- **About** → kept inline on the top-level list as a card (read-only info,
+  not worth a navigation hop). Card layout, top → bottom:
+  - **Identity** — app logo + name "Calendula", with "by Jean-Luc Makiola"
+    as a subtitle beneath the name
+  - **Action buttons** (small, button-styled, sit in a row):
+    - **Source** — Gitea logo, opens the repo (`about_source_url`)
+    - **License** — opens the LICENSE file on Gitea
+    - **Donate** *(tentative)* — sits next to Source; target TBD (decide
+      before building: Liberapay / Ko-fi / Gitea sponsor / etc.)
+  - **Version** — small version number at the bottom of the card
+
+Scope:
+- **Navigation** — add the settings sub-screen destinations alongside the
+  existing settings/calendars routes in `CalendarHost`; back pops to the
+  settings list (mind the existing `BackHandler` that guards against falling
+  through to the activity).
+- **Fix the dialog-pattern violation** — theme, week-start and language use
+  `DropdownMenu`; the project default is the full-width tonal OptionCard modal
+  (radio/dropdown/text-list dialogs are banned, see
+  `option-card-modal-style-default`). Migrate these selectors to OptionCard.
+- **Visual pass** — top-level category rows with leading icons; consistent
+  spacing and row affordances aligned with the event-form card design system.
+
+Out of scope (no new settings *features* here) — this is a structure + style
+pass on the existing controls; new toggles ride in with their own features.
+
+**Tier 2 — navigation & daily-driver completeness**
+5. ~~Jump-to-date — drawer date picker (un-cut from V1); cheap, fills the nav gap~~ *(done, v2.5.0)*
+6. ~~Agenda view — the missing 4th view; serves daily-driver users *and* becomes the data source for the widget~~ *(done, v2.5.0)*
+
+**Tier 3 — platform reach (depends on Tier 2)**
+7. ~~Home-screen widget — built on the agenda data source from #6~~ *(done, v2.5.0 — agenda + month widgets)*
+8. App shortcuts: ~~launcher long-press → New event~~ *(done, v2.5.0)*; ~~quick-settings tile~~ *(done, v2.8.0 — "New event" QS tile)*
+
+**Tier 4 — reliability, data-safety & interop** *(re-ranked 2026-06-17)*
+9. **Reminders — defaults + delivery reliability** *(shipped v2.6.0)* — global
+   default reminder **+ per-calendar override**, bundled with battery-exemption
+   hardening. Full sketch in "Reminders — defaults & delivery reliability" below.
+10. **The `.ics` engine — export + import** *(shipped v2.7.0, 2026-06-18)* — one
+    hand-rolled serializer/parser (zero deps, stays on `kotlinx-datetime`),
+    four surfaces all shipped: single-event share + whole-calendar backup
+    (export), open-`.ics`→form + whole-calendar bulk import (import). Closed the
+    device-local-calendar data-loss gap (#10/#11 merged here). Built as two
+    sequential branches: `feat/ics-export` (write side + UID-on-create precursor)
+    then `feat/ics-import` (parser, restore, dedup by UID). Import is
+    liberal-in/strict-out: skip-and-report foreign `VTIMEZONE` / `RECURRENCE-ID`
+    / guest lists it can't model. Plans:
+    `docs/superpowers/plans/2026-06-18-05-ics-export.md` + `…-06-ics-import.md`.
+11. **Snooze / dismiss notification actions** *(merged into release/v2.8.0)* —
+    followed the `.ics` work; inherits v2.6's deferred exact-alarm/WorkManager
+    decision (snooze must re-fire an alarm).
+
+**Tier 5 — close the read/write gap on the event model** *(opened 2026-06-22)*
+12. **Attendee editing** *(shipped — merged into release/v2.8.0, `feat/attendee-editing`
+    MR !29 / commit `b0f34ff`, 2026-06-22)* — closed the last big read-only gap in
+    the event model: attendees were already *read* (queried, mapped, shown on the
+    detail screen since v0.6) and are now *writable* from the form. An attendees
+    section on `EventEditScreen` / `EventForm` adds by typed email **or** the
+    no-permission contact picker, edits/removes rows, and sets role (required /
+    optional) — writing `CalendarContract.Attendees` rows on insert + dirty-checked
+    update, mirroring the reminders-diff pattern. The sync-adapter *invitation*
+    caveat was **settled record-only** (Calendula never sends invites; the backend
+    decides delivery) — full sketch + decision in "Attendee editing" under Locations
+    & People below.
+
+**Gated — explicit go/no-go before any work (mostly INTERNET-permission calls)**
+- Remote calendar create/edit (re-implements DAVx5; INTERNET + credential storage)
+- Locations & People — the no-permission contact pickers already shipped (location v2.8.0, attendee email v2.8.0); what remains gated is OSM autocomplete (needs INTERNET)
+- Move event to another calendar — sync-adapter minefield (copy+delete model)
+
+**Bottom — deprioritised, not important**
+- Duplicate event (detail action → prefilled create form) — moved here
+  2026-06-17; cheap but low value, pick up only if asked
+
+**Unranked / fill-in** — pinch-to-zoom time scale, tablet/foldable layouts.
+Pulled in opportunistically, not sequenced.
+
+Tier 4 is now fully shipped (#9 reminders defaults v2.6.0, #10 `.ics`
+export/import v2.7.0, #11 snooze/dismiss in release/v2.8.0; drag-drop rejected),
+and Tier 5 #12 — attendee editing — shipped in release/v2.8.0, closing the last
+read-only gap in the event model. v2.8.0 also cleared most Tier 2/3 leftovers —
+full-text search, the "New event" Quick Settings tile, and the now-line all
+shipped there. **No tier work is currently committed as next;** the remaining
+candidates are unscheduled theme-group ideas (pinch-to-zoom, tablet/foldable,
+accessibility pass) plus the gated go/no-go items.
+
+## Navigation & views
+
+- ~~Tap an empty slot in day/week → create form prefilled with that
+  date+time, snapped to the hour~~ **shipped v2.2.0** (long-press variant
+  not added — single tap covers it)
+- Agenda view (fourth view: upcoming events grouped by day; also the
+  natural data source for a future widget)
+- Jump to date — drawer date picker (un-cut from V1)
+- ~~Current-time "now" line in day/week~~ **shipped v2.8.0**
+- Week numbers in the **month** grid — **rejected** (owner decision): clutters
+  the view and shrinks the day cells; the badge stays week-view-only.
+- Pinch-to-zoom time scale in day/week
+- Tablet / foldable layouts *(was v3.0)*
+- ~~Full-text search~~ **shipped v2.8.0** — for a daily driver with real event
+  history, finding an event is core completeness, not optional.
+
+## Event editing & creation
+
+- Duplicate event (detail action → prefilled create form)
+- ~~**Per-event color**~~ *(shipped v2.4.0)* — `EVENT_COLOR` / `EVENT_COLOR_KEY`
+  from the calendar's color list (`Colors` table, `TYPE_EVENT`), OptionCard
+  picker in the form, falling back to the calendar color when unset. Reused the
+  color-picker component and palette plumbing from local calendar management and
+  finished the create/edit theme.
+
+## Calendars & accounts
+
+- ~~Create / manage local (device-only) calendars~~ **shipped v2.2.0** —
+  name + color + description; rename / recolor / delete the calendars the app
+  owns. Inserted under `ACCOUNT_TYPE_LOCAL` as a sync adapter; description in
+  `CAL_SYNC1`. Full-screen "Calendars" editor reached from Settings.
+- ~~Per-calendar "manage in source app" deep-link~~ **shipped v2.2.0** — for
+  synced calendars, open the app the calendar actually came from based on
+  its `ACCOUNT_TYPE` (DAVx5 `bitfire.at.davdroid`, Google `com.google`,
+  …); fall back to system account/sync settings. Plus an "add account"
+  entry into system Accounts. Honest boundary for remote calendars.
+- **Remote calendar create/edit** *(go/no-go)* — creating a CalDAV
+  collection (`MKCALENDAR`) or a Google calendar means an in-app sync
+  client: **INTERNET permission, credential storage, the full server
+  round-trip** — i.e. re-implementing DAVx5. DAVx5 exposes no public
+  intent to delegate the create to it. Cosmetic local edits (color/name)
+  to an existing synced row are possible but don't propagate to the server
+  and may be overwritten on next sync — not promised. Same explicit
+  go/no-go gate as the OSM/INTERNET item below.
+- Move event to another calendar (copy+delete model with a consequences
+  warning — deferred from v2.0; `CALENDAR_ID` is sync-adapter-owned) *(was v3.0)*
+- ~~**Local-calendar backup / export** *(Tier 4 #10)*~~ **shipped v2.7.0** —
+  device-only (`ACCOUNT_TYPE_LOCAL`) calendars had no sync and therefore no
+  backup. Settings → Calendars → Export writes every event to a user-chosen
+  `.ics` file (SAF); restore is the bulk-import path (pick a calendar, dedup by
+  UID). Closed the silent data-loss gap.
+
+### Disable a calendar in-app *(captured 2026-06-25)*
+
+A second, heavier visibility level **above** the existing per-view filter. Today
+the drawer's calendar filter (`hiddenCalendarIds` in `CalendarPrefs`) only hides
+a calendar's *events* from the month/week/day/agenda views — the calendar itself
+still clutters the drawer filter list, the event-form calendar picker, and the
+import target picker. "Disable" removes a calendar from the app's surfaces
+entirely; "hide" stays the lightweight, frequently-toggled control.
+
+**Two-level model (both kept):**
+- **Hidden** (existing) — `hiddenCalendarIds`; a quick per-view checkbox in the
+  drawer. Toggles events on/off in the views; the calendar stays listed
+  everywhere. Operates only over the *enabled* calendars.
+- **Disabled** (new) — the calendar is gone from the app: not in the drawer
+  filter list, not in the event-form picker, not in the import picker, and its
+  events never appear (it's gated out of `instances()` like a hidden one). It
+  remains visible **only** in Settings → Calendars, where the enable/disable
+  toggle lives, so it can be brought back.
+
+**Storage — app-side (DataStore), mirrors the hidden set.** Add
+`disabledCalendarIds: Set<Long>` + `setDisabledCalendarIds(...)` to
+`CalendarPrefs` (comma-separated string key, same shape as `hiddenCalendarIds`).
+**Does not touch** `CalendarContract.Calendars.VISIBLE` / `SYNC_EVENTS` — purely
+a Calendula-local preference, so other calendar apps are unaffected and the sync
+adapters stay out of it (privacy-clean, reversible).
+
+**Where the disabled set is applied:**
+- `CalendarRepositoryImpl.instances()` + `searchEvents()` — exclude
+  `calendarId ∈ (hidden ∪ disabled)` so a disabled calendar's events never show
+  and aren't searchable. (`repository.calendars()` itself stays unfiltered/raw —
+  the screens that need everything still get everything.)
+- `FilterViewModel.state` — drop disabled calendars from the drawer filter list
+  (you can't hide/show what's disabled).
+- `EventEditViewModel.writableCalendars` — exclude disabled, so you can't create
+  into a calendar you've removed from the app. Handle the last-used-calendar
+  preselect falling on a now-disabled calendar (fall back to first enabled
+  writable).
+- `ImportViewModel` — exclude disabled from the import target list.
+- `CalendarsScreen` / `CalendarsViewModel` — the **only** surface that lists
+  disabled calendars; add `setDisabled(id, Boolean)` and a per-calendar toggle.
+
+**UI — Settings → Calendars (no new tab).** Add an enable/disable control to each
+row on the existing `CalendarsScreen` (both the local and the synced/read-only
+groups — disabling is an app-side view choice, independent of write access).
+Disabled rows render visibly de-emphasised (dimmed) but keep the toggle so
+they're re-enableable. Follow the project dialog/list conventions (M3 grouped
+list, `option-card-modal-style-default` if a confirm/selection surface is needed).
+
+**Decided behaviour:**
+- All calendars disabled → views show the existing empty state.
+- A disabled calendar that still holds events: events simply vanish from
+  views/search until re-enabled (no data touched — it's a filter, not a delete).
+- Deep links / notifications pointing at an event in a disabled calendar still
+  open its detail screen — detail is a direct id lookup, not an `instances()`
+  query, so disabling never strands an existing link.
+
+## Reminders — defaults & delivery reliability *(shipped v2.6.0; built on `feat/default-reminders`)*
+
+Two themes bundled because both are "make reminders trustworthy" — the core of
+the "Calendula is your only calendar app" promise.
+
+**Built in this slice (A + the safe half of B):** global timed default reminder
++ a **separate all-day default** (day-scale lead times) + per-calendar override
+(timed events), applied on create with manual-edit / calendar-switch / all-day-
+toggle handling; three pickers + per-calendar override list in Settings →
+Notifications; battery-optimisation exemption row (status + system deep-link, no
+extra permission). `resolveDefaultReminder` + prefs round-trips unit-tested.
+Resolution model: all-day events use the all-day global default outright;
+per-calendar overrides govern timed events only. Reviewed (8-angle), fixes
+applied: form-reset state race, label-fn consolidation with the detail screen,
+inline wrapper + single combined flow read.
+
+**Deliberately deferred (documented decisions, not oversights):**
+- *Absolute time-of-day for all-day reminders* — the all-day default is still
+  minutes-before-midnight (day-scale presets), not "9am the day before" (open
+  decision #2's richer half). Per-calendar all-day overrides also deferred.
+- *Self-scheduled alarms* — kept the existing provider-broadcast architecture
+  (open decision #1). The battery exemption is the reliability lever; no
+  `AlarmManager`/`USE_EXACT_ALARM` subsystem was added.
+- *Test-reminder diagnostic* and *battery prompt inside onboarding* — the
+  exemption lives only in Settings for now (onboarding flow untouched to keep
+  the change reviewable).
+
+### A. Default reminders (global + per-calendar override)
+
+**No provider backing.** `CalendarContract` has no column that auto-applies a
+default reminder per calendar — Google's per-calendar defaults live server-side.
+So both the global default *and* the per-calendar override are **app-side
+preferences**, applied by us at event-insert time. We inherit nothing from the
+synced calendar.
+
+- **Storage (DataStore):**
+  - `defaultReminderMinutes: Int?` — global default; `null` = "no reminder".
+  - `defaultAllDayReminderMinutes: Int?` — separate all-day default (all-day
+    reminders are expressed as minutes before midnight / day-before-at-time, not
+    minutes before a start instant — they need their own value).
+  - `perCalendarReminderOverride: Map<Long, Int?>` — keyed by calendar id;
+    **absent key = inherit global**, explicit `null` = "no reminder for this
+    calendar". (Same for an all-day override map if we want per-calendar all-day.)
+- **Apply on create:** a fresh event prefills its reminders list from
+  override-or-global for the preselected calendar. Changing the calendar in the
+  form re-applies the *new* calendar's default **only if the user hasn't manually
+  edited the reminders** — track a dirty flag, mirroring the per-event-color
+  reset pattern (v2.4).
+- **Edit semantics:** defaults apply to **new events only**; never rewrite
+  reminders on existing events on open or on calendar-switch-during-edit.
+- **Settings UI (Notifications sub-page):**
+  - Global default via OptionCard (None / at time of event / 5 / 10 / 15 / 30 min
+    / 1 h / 1 day / custom), plus the separate all-day default.
+  - Per-calendar overrides: a row per writable calendar (in the Calendars screen
+    or a Notifications subsection), each opening the same OptionCard with a
+    leading **"Use global default"** option.
+
+### B. Delivery reliability (exact alarms + battery)
+
+The provider broadcasts `EVENT_REMINDER`, but on modern Android (Doze / OEM
+battery managers) delivery can be silently delayed or dropped. v1.4 deferred this;
+it directly undermines the feature's premise, so it rides in here.
+
+- **Exact alarm — decision first:** trust the provider broadcast, or
+  self-schedule via `AlarmManager.setExactAndAllowWhileIdle` for reliability?
+  If we self-schedule, declare `USE_EXACT_ALARM` (API 33+, auto-granted for
+  calendar/alarm-category apps, F-Droid-clean) with a `SCHEDULE_EXACT_ALARM`
+  fallback for API 31–32 (user-revocable → settings deep-link prompt).
+- **Battery-optimization exemption:** a *soft, optional* prompt via
+  `ACTION_REQUEST_IGNORE_BATTERY_OPTIMIZATIONS` (settings deep-link — never the
+  auto-grant intent), honest copy: "Android may delay reminders to save battery;
+  exempt Calendula for on-time delivery." Shown once after the existing
+  `POST_NOTIFICATIONS` onboarding step, reversible in Settings → Notifications.
+- **Diagnostics:** a "send a test reminder in 1 minute" button in Notifications
+  settings so users can verify delivery on their specific OEM (Samsung / Xiaomi
+  are notorious for suppressing it).
+
+### Decisions made (as shipped in v2.6.0)
+
+1. **Provider broadcast kept** — did not self-schedule via `AlarmManager`; the
+   battery-optimisation exemption is the reliability lever (simplicity + battery
+   cost won over the exact-alarm subsystem).
+2. **All-day reminders = minutes-before-midnight** (day-scale presets); absolute
+   time-of-day ("9am the day before") deferred — see the deferred list above.
+3. **Per-calendar overrides live in the Notifications sub-page** (override list),
+   governing timed events only.
+
+### Round two
+
+- ~~Snooze + dismiss actions on the notification~~ *(shipped in release/v2.8.0,
+  Tier 4 #11)* — snooze re-fires a snooze-only exact alarm.
+
+## Sharing & interop
+
+- ~~Share event as .ics + open/receive .ics into a prefilled create form~~
+  **shipped v2.7.0** — single-event share from detail; opening an `.ics` with one
+  event prefills the create form, many events opens a bulk import (dedup by UID)
+- ~~ICS file import~~ **shipped v2.7.0** — covered by the open/receive `.ics`
+  flow above (single → form, many → bulk import)
+
+## Platform & launchers
+
+- ~~Home-screen widget~~ **shipped v2.5.0** — agenda + month widgets
+- ~~App shortcuts (launcher long-press → New event)~~ **shipped v2.5.0**
+- ~~"New event" Quick Settings tile~~ **shipped v2.8.0**
+
+## Quality & reliability
+
+- **Accessibility pass** — TalkBack content descriptions across all screens,
+  dynamic-type / large-font reflow, touch-target audit. Quality bar for an
+  F-Droid app; nothing tracks it yet.
+- **Reminder delivery reliability** — exact alarms + battery-optimization
+  exemption; specced in the "Reminders — defaults & delivery reliability" slice
+  above (Tier 4 #9).
+
+## Locations & People *(go/no-go, captured 2026-06-11)*
+
+Beyond classic calendar-client scope; discussed, deliberately not planned
+in detail yet:
+
+- ~~**Contact address picker** for the location field via the system picker
+  (`ACTION_PICK`)~~ **shipped v2.8.0** — one-shot, needs no READ_CONTACTS, fits
+  the privacy story. The same no-permission mechanism was then reused for the
+  attendee email picker (v2.8.0).
+- **OSM address autocomplete** in the location field (type "Brandenburger
+  Tor" → tap suggestion → resolved address inserted). Backend would be
+  Photon (Nominatim's public policy forbids autocomplete). **Requires the
+  INTERNET permission** — first dent in the "no network access" promise;
+  if built: opt-in (off by default), honest copy, configurable endpoint
+  for self-hosters, onboarding footnote + F-Droid copy reworded. This
+  trade-off is an explicit go/no-go decision before any work starts.
+- **Inline contact suggestions** while typing (needs READ_CONTACTS) — only
+  if the picker proves clunky.
+- **Attendee editing** *(promoted out of this gated bucket 2026-06-22 — now
+  Tier 5 #12, high-importance; the no-permission typed-email path is not an
+  INTERNET/contacts call)*. See the "Attendee editing" sketch below.
+
+### Attendee editing *(Tier 5 #12, opened 2026-06-22)*
+
+The last read-only gap in the event model: attendees are read & shown on the
+detail screen (since v0.6) but the form can't write them. Make guests editable.
+
+- **Read side already done:** `Attendee` domain model + status/relationship/type
+  enums, `queryAttendees` + `EventDetailMapper.toAttendee` (with tests), and the
+  attendees `DetailCard` + `AttendeeRow` in `EventDetailScreen`. Nothing to add
+  there.
+- **Write side — SHIPPED (`feat/attendee-editing`, commit b0f34ff, 2026-06-22):**
+  `attendees` on `EventForm`; a Guests section in `EventEditScreen` rendered as an
+  inline grouped list — each guest a tonal card (avatar, name/email, tappable
+  Required/Optional role chip, remove), the trailing card an inline email field
+  (type → Done commits). Persisted by `reconcileAttendees` diffing the provider's
+  `CalendarContract.Attendees` rows on insert + dirty-checked update (new guests =
+  `RELATIONSHIP_ATTENDEE` / `STATUS_INVITED`; kept rows keep their status, only the
+  required/optional type updates; organizer/resource/no-email rows untouched).
+  Reminders restyled to the same grouped-list pattern in passing. Needs only the
+  existing `WRITE_CALENDAR` — no new permission.
+- **Name on manual add — SHIPPED via a contact picker** (2026-06-22). The inline
+  field is email-only (the quick path); the add row also has a **"from contacts"
+  button**: `ACTION_PICK` on `ContactsContract.CommonDataKinds.Email.CONTENT_URI` →
+  the system Contacts app returns a URI to the picked email row, queried for
+  `Email.ADDRESS` **and** the contact `DISPLAY_NAME`, so a picked guest gets both
+  email and name in one tap. The result Intent grants temporary read access, so
+  **no `READ_CONTACTS` permission** — one-shot and user-driven, same no-permission
+  mechanism as the location address picker above. Self/organizer rows stay
+  non-editable.
+- **Invitation behavior — DECIDED 2026-06-22: record-only, all writable
+  calendars.** Calendula has no INTERNET and never sends an invitation itself; it
+  only writes `Attendees` rows. Whether a guest is notified is decided downstream:
+  local calendars notify no one (no sync); CalDAV/DAVx5 PUTs the `ATTENDEE` lines
+  and the *server* decides iMIP delivery; Google's sync adapter pushes the change
+  and Google decides (third-party attendee writes are historically unreliable
+  there). Editing is allowed on **any writable calendar** — not gated to local.
+  - **Honest, backend-aware copy is mandatory** (this is the whole point of the
+    decision): on a synced calendar show "Calendula doesn't send invitations —
+    your calendar account may email guests when it syncs"; on a local calendar
+    show "Stored on this device. No one is notified."
+  - Calendula must **not fabricate an ORGANIZER** or otherwise fake scheduling
+    state to coax a send — it writes the guest list faithfully and leaves
+    scheduling entirely to the backend.
+  - The optional "send an .ics invite via your email app" delegate (`ACTION_SEND`,
+    still no INTERNET) was considered and **deferred** — revisit only if users ask
+    to notify guests explicitly.
+- **Out of scope (for now):** RSVP/your-own-response editing, free/busy lookups,
+  resource booking — all carry server round-trips or richer sync semantics.
+
+## Consciously rejected
+
+- Travel time / weather / smart suggestions (network, core-promise conflict)
+- Natural-language quick entry (high effort, locale-fragile; the prefilled
+  form already covers fast entry)
+- Quick-add sheet (the prefilled full form already covers it — cut in v2.0)
+- Drag & drop rescheduling in day/week — **rejected** (owner decision,
+  reaffirmed 2026-06-22): not wanted. Rescheduling stays via the edit form.

.planning/STATE.md

@@ -1,11 +1,27 @@
 # Calendula — Current State
 
-*Last updated: 2026-06-08*
+*Last updated: 2026-06-22*
 
 ## Status
 
-**Milestone:** v0.2 — Data Layer & Permission Flow
-**Phase:** Plan 02 complete; UI-design iteration pending before Plan 03
+**Milestone:** 2 (write support) **complete** — v2.0.0 shipped 2026-06-11.
+**Phase:** post-2.x theme-based backlog work (organised in `ROADMAP.md`).
+**Latest released tag: v2.7.5.** The whole Tier 4 (reliability/data-safety/
+interop) arc is now done or in flight:
+- v2.4.0 per-event colors (2026-06-17)
+- v2.5.0 jump-to-date, Agenda view, agenda + month home-screen widgets, "New
+  event" launcher shortcut (2026-06-17)
+- v2.6.0 default reminders (global + per-calendar override, all-day default,
+  battery-exemption row) + system per-app language (2026-06-18)
+- v2.7.0 **`.ics` engine** — single-event share, local-calendar backup export,
+  open/receive `.ics` (single → form, many → bulk import, dedup by UID)
+  (2026-06-18)
+- v2.7.1–v2.7.5 — crash-reporting + F-Droid reproducible-build hardening + fixes
+
+**Next release `release/v2.8.0` (integration branch, not yet cut to main):**
+holds crash reports via the public Codeberg tracker (MR !27) + reminder
+snooze/dismiss notification actions (MR !28). Version bump to 2.8.0 happens at
+release-cut.
 
 ## Progress
 
@@ -13,11 +29,149 @@
 - [x] V1 design decisions resolved (App name "Calendula", icon, seed color)
 - [x] Plan 01 written and executed — foundation lands (theme, icon, i18n, Hilt, DataStore, CI green)
 - [x] Plan 02 written and executed — data layer + permission flow + debug screen
-- [ ] UI-design iteration (mockups for Month/Week/Day/Detail/Filter/Settings, all three states)
-- [ ] Plan 03 (Month view)
+- [x] Month view (S1) — 6-week grid, event dots, today marker, swipe nav, three states (replaces debug screen)
+- [x] Week view (S2) — time schedule with overlap-resolved lanes, all-day strip, swipe nav, three states
+- [x] Day view (S3) — single-column slice reusing the week layout
+- [x] View-switcher (M1) wired — cycles Month ↔ Week ↔ Day
+- [x] Event-detail screen (S4) — full-screen, humanized recurrence
+- [x] Filter sheet (M3) — per-calendar visibility, grouped by account, persisted, applied centrally in the repository
+- [x] Settings (M4) — appearance (theme, dynamic colour, week start), language (per-app locales), about
+- [~] Jump-to-date (M2) — **cut from scope**; "Today" half shipped in v0.5, date-picker dropped
+- [x] Full event read (v0.6) — reminders, status, availability, access level,
+  attendee role + self-response, foreign timezone, and linkified description
+  URLs in the detail view; new domain enums + mapper unit tests. (A dedicated
+  URL field was cut — no `CalendarContract` column backs it.)
+
+- [x] v1.1 write foundation — `WRITE_CALENDAR` (onboarding asks READ+WRITE,
+  only READ gates; contextual upgrade for v1.0 installs), read-only-calendar
+  detection (`CALENDAR_ACCESS_LEVEL` → `canModifyContents`, actions hidden for
+  WebCal/birthday calendars), delete from the detail screen (recurring:
+  "only this event" via cancelled exception / "all events in the series"),
+  repository + mapper tests
+
+- [x] v1.2 create event — full-screen `EventEditScreen` (title, all-day,
+  M3 date/time pickers with duration-preserving start moves, writable-only
+  calendar picker preselecting the last-used calendar, location, description),
+  "+" FAB on all three views prefilled with the visible day, `insertEvent`
+  with provider-correct all-day normalisation (UTC midnights, exclusive end),
+  domain/mapper/repository tests
+
+- [x] v1.3 edit event (shipped 2026-06-11) — `EventEditScreen` reused for
+  edit (detail-screen Edit action, `canModify`-gated, contextual WRITE
+  upgrade), dirty-checked partial `update` on the Events row (recurring:
+  series DTSTART moves by the user's delta, DURATION instead of DTEND),
+  reminder diff by minutes (kept rows keep their method), simple recurrence
+  picker (FREQ/INTERVAL/UNTIL/COUNT; complex RRULEs preserved verbatim and
+  shown humanized), `EventFormField.Recurrence` incl. settings default,
+  recurrence also available on create; domain/mapper/repository tests.
+  Review round 1: weekly BYDAY day-toggles in the custom picker ("every week
+  on Mon+Fri"). Review rounds 2–4: occurrence edit pulled forward from v2.0
+  and made three-way like delete ("this" = exception row via
+  `CONTENT_EXCEPTION_URI`, "this and following" = series split, "all" =
+  series update); delete equally three-way (truncation via RRULE UNTIL);
+  the edit-scope question moved to save time (Google model) — dirty
+  recurring saves park in `SaveUiState.AwaitingScope`, a changed rule drops
+  the "only this event" option
+
+- [x] v1.4 reminder notifications (shipped 2026-06-11) — exported
+  `EVENT_REMINDER` receiver → `CalendarAlerts` (SCHEDULED & due) →
+  dedicated channel, tap opens detail (singleTop deep link); best-effort
+  FIRED marking; one-time onboarding step requesting `POST_NOTIFICATIONS`
+  with duplicate-reminders warning; Settings mirror. Provider only fires
+  `METHOD_ALERT` rows (AOSP-verified), so email reminders never reach us
+
+- [x] v2.0 conflict dialog + store polish (shipped 2026-06-11 as v2.0.0) —
+  `EditSnapshot` compare on save (overwrite/discard; deleted → close),
+  quick-add cut, calendar-switch → v3 backlog; F-Droid/README copy
+  refreshed, fastlane screenshots DE+EN captured on-device
+
+- [x] v2.1 (shipped 2026-06-15) — month grid shows real events as
+  continuous multi-day bars; navigation-drawer View section
+  (Month/Week/Day); cursor-jump fix in event text fields
+
+- [x] v2.2 (shipped 2026-06-16) — tap an empty slot in day/week to create
+  (prefilled with that day + tapped hour, snapped to the hour); local
+  calendar management in a full-screen editor from Settings →
+  Calendars: create/rename/recolor/delete device-only calendars
+  (`ACCOUNT_TYPE_LOCAL`, sync-adapter insert) with name, pastel-previewed
+  colour, and description (stored in `CAL_SYNC1`); synced calendars listed
+  read-only grouped by account with a per-account "manage in source app"
+  deep-link (resolved from the account's authenticator: DAVx5/ICSx5/…) and
+  an add-account shortcut. Shared `InlineTextField` extracted to `ui.common`
+
+- [x] v2.3 settings/calendars/drawer redesign (shipped 2026-06-16) — adopted a
+  shared Material 3 grouped-list blueprint, modelled on the ReFra gallery app
+  and extracted to `ui/common/GroupedList.kt` (`CollapsingScaffold` with a
+  `LargeTopAppBar` exit-until-collapsed title; `GroupedRow` with Position-based
+  corner grouping, press-animated corners, `selected` + `minHeight` knobs).
+    - Settings: category hub (About card on top → version mark at the foot) with
+      sliding sub-pages (Appearance / New event form / Notifications); token-
+      based icon chips; theme/week-start/language pickers migrated from
+      `DropdownMenu` to OptionCard dialogs. New `ic_gitea.xml` (Simple Icons,
+      verbatim path) for the About "Source" button; en+de strings.
+    - Calendar manager: same collapsing scaffold + grouped rows; shared
+      `CalendarColorChip` (neutral chip, pastelised calendar glyph).
+    - Navigation drawer: branded header, grouped View switcher (active view
+      highlighted via `secondaryContainer`), the filter list restyled to
+      grouped rows with a trailing checkbox; the whole drawer scrolls as one.
+    - Cards use `surfaceContainerHigh` for readable contrast against `surface`.
+    - Donate button on the About card deferred (target still TBD).
+
+- [x] v2.4 per-event color (shipped 2026-06-17) — an optional "Color" field in
+  the event form. Read/render already resolved `EVENT_COLOR` with a calendar
+  fallback; this adds the write side and the picker. Palette-backed calendars
+  (Google, some CalDAV) pick from the account's `Colors` (`TYPE_EVENT`) and
+  write `EVENT_COLOR_KEY` so the color round-trips through sync; local
+  calendars write a raw `EVENT_COLOR` from the shared `CALENDAR_COLOR_PALETTE`
+  (extracted with the swatch row to `ui/common/ColorSwatchRow.kt`). Switching
+  calendars resets the choice (a key is account-scoped). A settings toggle
+  ("Allow colors on unsupported calendars", off by default) extends the raw
+  path to synced calendars with no palette, with an honest "may not survive
+  sync" warning on the picker and in Settings. Color writes flow through
+  insert / dirty-checked update / occurrence-exception; mapper + form tests.
+
+- [x] v2.5 (shipped 2026-06-17) — Agenda view (4th top-level view),
+  jump-to-date drawer date picker, two home-screen widgets (scrolling
+  "Upcoming" agenda + month grid), and a "New event" launcher long-press
+  shortcut
+
+- [x] v2.6 (shipped 2026-06-18) — default reminders: global timed default +
+  separate all-day default + per-calendar override (timed), applied on create
+  with dirty-flag handling; three pickers + override list in Settings →
+  Notifications; battery-optimisation exemption row (status + system deep-link,
+  no new permission). Plus system per-app language (Android 13+) and an
+  immediate-effect fix for the in-app language picker
+
+- [x] v2.7 (shipped 2026-06-18) — the `.ics` engine: share a single event as
+  `.ics` from the detail screen; back up local calendars (Settings → Calendars
+  → Export) to a SAF file; open/receive an `.ics` — one event prefills the
+  create form, many events open a bulk import into a chosen calendar (dedup by
+  UID, skip-and-report unrepresentable VTIMEZONE / RECURRENCE-ID / guests).
+  Hand-rolled serializer/parser, zero deps. Plus all-day single-day UTC fix and
+  a widget R8 keep-rule crash fix
+
+- [x] v2.7.1–v2.7.5 (2026-06-21) — launch crash fix (listener before grant),
+  user-controlled crash reporting, widget loading-spinner R8 keep rule, and
+  F-Droid reproducible-build cleanups for the official repo
+
+- [~] release/v2.8.0 (not yet cut) — crash reports via the public Codeberg
+  tracker (MR !27) + reminder snooze/dismiss notification actions (MR !28,
+  snooze self-schedules an exact alarm; primary delivery stays provider-broadcast)
 
 ## Next
 
-1. Iterate on UI design (mockups per screen, all three states)
-2. Write Plan 03: Month view
-3. Execute Plan 03 — Debug screen gets replaced by month view
+1. Cut **v2.8.0** from `release/v2.8.0` (bump versionName → tag via the
+   merge-driven pipeline) once on-device review signs off
+2. **Attendee editing** — the committed next feature (Tier 5 #12, high-
+   importance, opened 2026-06-22). Attendees are already read & shown on the
+   detail screen since v0.6; the gap is the write side — make guests editable
+   in `EventEditScreen` / `EventForm` (add by typed email, role, remove),
+   persisted by diffing `CalendarContract.Attendees`. No new permission for the
+   typed-email path. **Invitation behavior DECIDED 2026-06-22: record-only on all
+   writable calendars** — Calendula never sends (no INTERNET); honest backend-aware
+   copy ("your account may email guests when it syncs" on synced calendars, "no one
+   is notified" on local). Full sketch in `ROADMAP.md` → "Attendee editing".
+3. Then: the two INTERNET go/no-go calls (OSM autocomplete, remote calendar
+   create/edit) and Tier 2/3 leftovers (quick-settings tile, now-line, week
+   numbers in month, full-text search, accessibility pass). Drag-and-drop
+   rescheduling is **rejected**.

CHANGELOG.md

@@ -5,7 +5,736 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased]
+## [2.13.0] — 2026-07-03
+
+### Added
+- Calendula now speaks Spanish and Italian. Both arrived as community
+  translations through [Calendula's Weblate](https://weblate.dev.jeanlucmakiola.de/projects/calendula/)
+  — a **huge thank you** to
+  [kikerw](https://weblate.dev.jeanlucmakiola.de/user/kikerw/) for the Spanish
+  translation and to
+  [corrent](https://weblate.dev.jeanlucmakiola.de/user/corrent/) for the Italian
+  one! Pick your language under Settings → Language or in Android's per-app
+  language settings. Strings added in this very release may still show in
+  English until the translations catch up. Want Calendula in your language?
+  Translating happens entirely in the browser — every contribution is welcome.
+- See your contacts' birthdays and anniversaries in your calendar. A new,
+  **optional** feature (Settings → Contact special dates) mirrors your contacts'
+  birthdays, anniversaries and other dates into local "Birthdays",
+  "Anniversaries" and "Other dates" calendars that stay in sync as your contacts
+  change. Each is a normal local calendar, so you set its colour, visibility and
+  reminders the usual way — new birthdays even start with a reminder a week before
+  *and* on the day. The title format is yours to customise (`{name}`, `{year}`).
+  This is the first feature to use the contacts permission: it is requested only
+  when you turn the feature on, everything stays on your device (Calendula has no
+  internet access), and your contacts are only ever read, never changed. Thanks
+  to @moonj for the suggestion ([#15]).
+- Set more than one default reminder per calendar. A calendar's default
+  reminders — and the global defaults under Settings → Notifications — can now
+  hold several lead times instead of just one, so new events can start with, say,
+  a reminder a week before *and* one on the day. The reminder pickers are now
+  multi-select; per-calendar overrides can still inherit the global default or
+  turn reminders off entirely. Thanks to @moonj for the suggestion ([#14]).
+- Widget headers now open the app. Tapping the month/year title on the month
+  widget opens the app on the month view, and tapping the "Upcoming" title on
+  the agenda widget opens it on your default view — so there's a one-tap way
+  back into the app that lands where you'd expect, instead of only through a day
+  or event. On the month widget, tapping anywhere on a day — not just the small
+  date number — now opens that day, and the "today" button snaps the grid back
+  to the current month in place. Thanks to @rgz46vic and @ptab for the
+  suggestions ([#18], [#20]).
+- Make Calendula's text your own. Settings → Appearance gains **Headings font**
+  and **Body font** pickers: keep the system default, choose a bundled face
+  (Atkinson Hyperlegible, Lora, JetBrains Mono — each previewed in its own
+  face), or load any `.ttf`/`.otf` file from your device, independently per
+  role. Font size and colour stay with Android's accessibility scaling and the
+  app theme, as discussed on the issue. Thanks to @abrossimow for the
+  suggestion ([#19]).
+- Choose what the view-switch button cycles through. Settings → Appearance now
+  lets you pick which views the top-right quick-switch button rotates between
+  and drag them into your preferred order; views you switch off stay reachable
+  from the navigation menu, which can be reordered the same way. Thanks to
+  @abrossimow for the suggestion ([#24]).
+
+### Fixed
+- Month widget arrows and "today" button work again. On release builds the
+  prev/next-month arrows and the jump-to-today control on the month widget did
+  nothing when tapped — code shrinking had stripped the tap handlers behind
+  them. They respond again. Thanks to @rgz46vic for the report ([#18]).
+- Disabled calendars no longer notify. Reminders for events in a calendar you
+  have disabled (Settings → Calendars) are now suppressed instead of still
+  popping up — matching how a disabled calendar's events already stay hidden
+  everywhere else in the app ([#17]).
+- Editing a single occurrence of a recurring event works again. Choosing **Only
+  this event** and saving a change to one event in a repeating series silently
+  did nothing — the change was rejected and the edit form simply reappeared with
+  nothing applied. The edited occurrence is now stored correctly, so the change
+  lands on just that one event and leaves the rest of the series untouched
+  ([#16]).
+- Every calendar can be picked when creating an event. The event editor's
+  calendar picker was a fixed-height dialog, so with many calendars anything
+  past the first nine or so was simply unreachable. It is now a full-screen,
+  scrollable list grouped by account, with each calendar's colour shown.
+  Thanks to @dschuermann for the report ([#29]).
+
+## [2.12.0] — 2026-06-28
+
+### Added
+- See past events your way. Two new settings change how events that have already
+  ended are shown. **Past events** (Settings → Appearance → Agenda) lets the
+  agenda — both in the app and the home-screen "Upcoming" widget — keep them as
+  usual, dim them, or hide them from the list entirely. **Dim completed events**
+  (Settings → Appearance) separately fades finished events in the month and week
+  views. Both are off by default, an event only counts as finished once it has
+  actually ended (events still in progress are never dimmed), and the lists
+  update on their own as the day goes on. Thanks to @ptab for the suggestion
+  ([#12]).
+
+### Changed
+- Readable titles on overlapping events. In the week and day views, events that
+  overlap split a day into slim columns where the title used to be clipped to a
+  character or two. The title now wraps across as many lines as the block can
+  fit, and the time is hidden on those narrow blocks so the name can fill the
+  space — so you can tell events apart without opening each one. Thanks to @ptab
+  for the suggestion ([#13]).
+
+## [2.11.2] — 2026-06-28
+
+### Added
+- Jump straight to typing a title. When you start a new event, Calendula now puts
+  the cursor in the title field and opens the keyboard right away, so you can type
+  the name without an extra tap. It's on by default and only affects creating an
+  event — editing never grabs focus — and a new **Focus title on new event**
+  switch (Settings → New event form) turns it off. Thanks to @abrossimow for the
+  suggestion ([#10]).
+
+## [2.11.1] — 2026-06-28
+
+### Fixed
+- Calendula can now be set as your default calendar app. It registers the
+  calendar-app intent filters the system uses, so it appears in the chooser when
+  you tap a date in a launcher or clock — and opening one takes you straight to
+  that day. Android has no way for an app to make itself the default, so you pick
+  it once from the system picker. Thanks to @abrossimow for the report ([#9]).
+
+## [2.11.0] — 2026-06-27
+
+### Added
+- Start the week on any day. The **Week starts on** setting (Settings →
+  Appearance) now offers every weekday — not just Monday or Sunday — alongside
+  the automatic, locale-based default. Thanks to @zmaherdev for the suggestion
+  ([#3]).
+- Choose a 12- or 24-hour clock. A new **Time format** setting (Settings →
+  Appearance) lets you force a 12-hour (2:00 PM) or 24-hour (14:00) clock, or
+  follow the system setting automatically. It applies everywhere times appear —
+  the week and day timelines, agenda, event details, search and reminders — so
+  the format is now consistent across the whole app. Thanks to @zmaherdev for
+  the suggestion ([#6]).
+- Optional hour lines in the timeline. A new **Hour lines** switch (Settings →
+  Appearance) draws a faint separator at each hour in the week and day views,
+  making it easier to see when events start and end. Off by default. Thanks to
+  @zmaherdev for the suggestion ([#5]).
+- Limit how far ahead the agenda looks, and switch it on the fly. New **Agenda
+  range** and **Agenda widget range** settings (Settings → Appearance) let the
+  agenda screen and its home-screen widget each show just today, the rest of this
+  week, the rest of this month, a rolling 7 or 30 days, or a custom number of
+  days — "This week" follows your week-start. The agenda also gains a bar at the
+  top naming the exact dates in view, with a button to switch the range just for
+  the current session (it resets when you reopen the app); the bar can be turned
+  off. Thanks to @zmaherdev for the suggestion ([#4]).
+- Automatic backup of local calendars. A new **Automatic backup** option
+  (Settings → Calendars → Backup) periodically exports your local calendars to an
+  `.ics` file in a folder you choose, on an interval you set (from 30 minutes up).
+  Useful for file-based syncing such as Syncthing, or simply as a safety net — it
+  is a one-way export and never touches your synced accounts. Thanks to @shield
+  for the discussion that inspired it ([#7], [#8]).
+- Field icons in the event-form settings. Each optional-field toggle (Settings →
+  Event form) now shows the same icon the field uses in the new-event form, so
+  the list is easier to scan.
+- Help translate Calendula. A **Help translate** link at the top of **Settings →
+  App language** opens the project's Weblate, where you can add or improve a
+  language in your browser — no coding needed. Contributions in any language are
+  welcome.
+
+### Changed
+- Tidied **Settings → Appearance** into clearer groups (theme & colour, calendar,
+  agenda), and the agenda's empty state now reads "You're all caught up".
+- Reworked **Settings → Calendars**. Local and synced calendars are now grouped
+  into collapsible, source-branded cards — each account shows its app's icon —
+  with a per-account menu to enable or disable all of its calendars at once or
+  open the account in its source app.
+- Reorganised **Settings → Notifications**: reliable-delivery and snooze settings
+  moved up with the other global reminder options, and the per-calendar reminder
+  overrides now fold into a single expandable section.
+- Moved **Add Quick Settings tile** out of the event-form section to its own
+  top-level entry in Settings.
+
+## [2.10.0] — 2026-06-25
+
+### Added
+- Turn a calendar off across the whole app. Settings → Calendars now has a
+  switch on every calendar — both your own and synced ones. Switching one off
+  removes it everywhere: its events disappear from all views and search, and it
+  drops out of the drawer's hide/show filter, the event-form calendar picker and
+  the import target picker. Unlike hiding (the quick per-view checkbox in the
+  drawer), a disabled calendar leaves the app entirely until you turn it back on.
+  Nothing is deleted and no other app is affected — it's a Calendula-only view
+  choice — so you can re-enable it any time from the same screen, where disabled
+  calendars stay listed but dimmed.
+- An optional way to support development. Settings → About now has a "Support
+  development" button that opens Ko-fi in your browser. It's a plain donation
+  link with no perks attached, and it needs no new permissions — Calendula still
+  has no internet access of its own and just hands the link to your browser.
+
+## [2.9.0] — 2026-06-25
+
+### Added
+- Choose the view Calendula opens on. A new **Default view** setting (Settings →
+  Appearance) lets you pick Month, Week, Day or Agenda as the view shown each
+  time you start the app, instead of always opening on Week. Thanks to
+  @devinside for the suggestion ([#1]).
+- The month widget is now interactive: tap any day to open it, or tap an event to
+  open its details. Previously only the month's prev/next/today controls
+  responded. Thanks to @devinside for spotting this ([#2]).
+- Predictive back. Swiping back from a screen — an event, the editor, search or
+  settings — now follows your finger, shrinking the screen to preview what's
+  behind so you can see where Back will take you before you let go; slide it back
+  to cancel. The preview needs Android 14 or newer; on older versions Back works
+  as before.
+- Respect for "Remove animations". If you've turned animations off in your
+  device's Accessibility settings, Calendula now honours it everywhere: motion
+  collapses to a quick fade and the back preview is skipped.
+
+### Changed
+- Smoother, more consistent motion throughout. Expanding sections, list updates
+  in search and agenda, and the onboarding screens now animate the same way
+  across the app, instead of some places sliding or growing while others popped
+  in. Switching between Month, Week, Day and Agenda now cross-fades rather than
+  snapping, while paging within a view keeps its slide.
+
+### Fixed
+- Home-screen widgets now back out the way you came in. A day or event opened
+  from the Agenda widget keeps you in the agenda context, and from the Month
+  widget in the month context — pressing Back returns there instead of dropping
+  you on the week view. More broadly, the app now keeps a real view history:
+  switching views and drilling into a day are retraced by Back one step at a
+  time, down to your default view before the app exits. Thanks to @devinside for
+  reporting ([#2]).
+
+## [2.8.0] — 2026-06-23
+
+### Added
+- Find events fast. A search button in the top bar of every calendar view opens
+  a search box — type a couple of letters and matching events (by title,
+  location or description) appear, soonest first with past events below. Tap a
+  result to open it. Search covers your whole calendar, not just what's on
+  screen, and skips calendars you've hidden. A recurring event shows its next
+  occurrence rather than the date the series first started.
+- A current-time line in the day and week views. A thin coloured line marks the
+  present moment across today's column, so you can see at a glance where you are
+  in the day. It updates every minute and only appears when today is in view.
+- Add and remove event guests. The create/edit form now has a Guests section:
+  add people by email or pick them from your contacts, mark each as required or
+  optional, and remove them. Calendula never sends invitations itself (it has no
+  internet access) — it only records the guests; if the event lives on a synced
+  account, that account may email them when it syncs, and on a local calendar no
+  one is notified. The form tells you which applies. Picking a guest from
+  contacts needs no contacts permission.
+- Pick a location from your contacts. A contacts button beside the location
+  field drops a contact's address straight into an event — handy for a meeting
+  at someone's home or office. Like the guest picker, it needs no contacts
+  permission.
+- A "New event" Quick Settings tile. Add it to your quick settings to jump
+  straight into the new-event form from anywhere. Settings → New event has a
+  one-tap button to add the tile (Android 13+); on older versions you can add it
+  from the quick-settings editor.
+- Snooze and dismiss buttons on reminder notifications. Dismiss clears the
+  reminder; snooze hides it and brings it back after a delay you pick in
+  Settings → Notifications (5 to 60 minutes, default 10). Android's calendar
+  system won't re-post a reminder on its own, so Calendula schedules an exact
+  alarm to bring a snoozed one back on time.
+
+### Changed
+- Event details now show each guest's email beneath their name, instead of only
+  when no name is available.
+- Crash and problem reports now open on the project's public Codeberg tracker,
+  where anyone can register and file an issue. Nothing is sent automatically —
+  you still review the report and submit it yourself in the browser.
+
+## [2.7.5] — 2026-06-21
+
+### Changed
+- Further build cleanup for the official F-Droid repository: stopped embedding
+  AGP's dependency-metadata block in the APK, which F-Droid's reproducible-build
+  scanner rejects as an extra signing block. No functional or visible changes —
+  the same app as 2.7.4, just without that Play-oriented metadata blob.
+
+## [2.7.4] — 2026-06-21
+
+### Changed
+- Build cleanup that lets Calendula ship in the official F-Droid repository:
+  removed an unused Gradle toolchain-resolver plugin, which F-Droid's offline,
+  reproducible build process disallows. No functional or visible changes — this
+  is the same app as 2.7.3.
+
+## [2.7.3] — 2026-06-21
+
+### Fixed
+- Home-screen widgets no longer get stuck on a loading spinner in the published
+  (F-Droid) release build. They render via Android's background-work system, and
+  release optimisation (R8) was stripping a helper class it loads by name, so the
+  render job never ran. Added the missing keep rule — widgets now load normally.
+
+## [2.7.2] — 2026-06-21
+
+### Added
+- Crash reporting you control. If Calendula closes unexpectedly, it now captures
+  a technical report and, on the next launch, offers to send it as an issue on
+  the project's tracker. Nothing is uploaded automatically — the report stays on
+  your device until you choose to share it, it contains no personal data or
+  calendar content (only the app, Android and device versions plus the stack
+  trace), and you see the full text before sending. There's also a "Report a
+  problem" entry in Settings, and if the app ever fails to start repeatedly, a
+  minimal recovery screen still lets you send the report.
+
+## [2.7.1] — 2026-06-21
+
+### Fixed
+- Fixed the app crashing immediately on launch whenever calendar access hadn't
+  been granted yet (a fresh install, or after revoking the permission). The app
+  set up its live calendar-change listener before the permission screen could
+  appear, which newer Android versions reject outright — so the app died before
+  you could grant access. The listener now waits for the permission and attaches
+  itself the moment it's granted.
+
+## [2.7.0] — 2026-06-18
+
+### Added
+- Share a single event as an `.ics` file from the event detail screen — hands a
+  standard calendar file to any app via the system share sheet.
+- Back up your local (device-only) calendars: Settings → Calendars → Export as
+  `.ics` file writes every event of your on-device calendars to a file you
+  choose. Local calendars aren't synced anywhere, so this is their only backup.
+- Open or share an `.ics` file into Calendula: a single event opens the create
+  form prefilled for review, while a file with many events (e.g. a backup) opens
+  a bulk import — pick a calendar and import them all. Re-importing a backup
+  won't create duplicates (events are matched by their unique identifier), and
+  anything Calendula can't represent (changed recurring occurrences, guest
+  lists) is reported rather than silently dropped.
+
+### Fixed
+- All-day events that cover a single day (e.g. a birthday) no longer show up on
+  the following day as well — in the day, week and month views or on the event
+  detail screen. The extra day came from interpreting the all-day date range in
+  the device's time zone instead of UTC.
+- Fixed the app crashing immediately on every launch in the optimized release
+  build: release code-shrinking (R8) was stripping a database class the
+  home-screen widget framework needs, so the app died at startup before showing
+  anything. Added the missing keep rule.
+
+## [2.6.0] — 2026-06-18
+
+### Added
+- App language can now be set from Android's system per-app language settings
+  (Android 13+), in addition to the in-app picker in Settings — and the app is
+  set up so further languages can be added by community translators
+
+### Fixed
+- Changing the app language in Settings now takes effect immediately; the
+  picker previously had no effect
+
+## [2.5.0] — 2026-06-17
+
+### Added
+- Home-screen widgets (two of them): an "Upcoming" agenda widget — a scrolling
+  list of the next month of events grouped under day headers, with refresh and
+  "New event" buttons — and a month-grid widget showing the full month with
+  today highlighted, connected multi-day event bars, and prev/next/today
+  navigation. Both reuse the in-app grouping and layout so they match the app
+  exactly, respect your hidden-calendar choices, and refresh automatically when
+  the calendar changes or the day rolls over. Tapping a day opens that day;
+  tapping an event opens its details
+- App shortcut: long-press the Calendula icon for a "New event" action that
+  jumps straight into the create-event form
+- Agenda view — a fourth top-level view alongside Month/Week/Day: a
+  forward-looking list of upcoming events grouped under "Today"/"Tomorrow"/date
+  headers, reachable from the view switcher
+- Jump to date — a "Jump to date" row in the navigation drawer opens a date
+  picker and moves the active view (Month/Week/Day/Agenda) to the chosen day
+
+## [2.4.0] — 2026-06-17
+
+### Added
+- Per-event colors: give a single event its own color, instead of always
+  inheriting its calendar's. Add the new "Color" field from "More fields" in
+  the event form. On calendars that publish their own color set — such as
+  Google — you pick from that calendar's palette, so the color is stored
+  with the event and shows correctly on every synced device. On local
+  calendars you pick from Calendula's palette. "Reset" returns an event to
+  its calendar's color
+- A new "Allow colors on unsupported calendars" setting (New event form,
+  off by default) extends per-event colors to calendars that publish no
+  color set of their own (some CalDAV). Such a color is kept on the device
+  and may be dropped or overwritten on that calendar's next sync — a
+  limitation of those calendars, called out plainly in the setting and on
+  the color picker
+
+## [2.3.0] — 2026-06-16
+
+### Changed
+- Redesigned Settings around the Material 3 grouped-list pattern: a large
+  title that collapses into the toolbar as you scroll, category cards on the
+  main screen, and dedicated sub-pages for Appearance, the new-event form, and
+  Notifications. The theme, week-start and language pickers now use the app's
+  standard option-card dialogs instead of dropdown menus
+- About moved to the top of Settings as a card — app icon, author, and quick
+  links to the source code and licence — with the version shown plainly at the
+  foot of the list
+- The Calendars screen now uses the same grouped-card layout and collapsing
+  title, and each calendar shows a soft pastel-tinted calendar glyph rather
+  than a plain colour swatch
+- Redesigned the navigation drawer to match: a branded header, the
+  Month / Week / Day switch and your calendars as grouped cards (with the
+  active view highlighted), and the whole drawer now scrolls as one
+
+## [2.2.0] — 2026-06-16
+
+### Added
+- Tap an empty slot in the day or week view to create an event there: the
+  create form opens prefilled with that day and the tapped hour (snapped to
+  the hour, one hour long). Tapping an existing event still opens it
+- Local calendars: create and manage device-only calendars that live
+  entirely on this phone — no account, no sync — from a new "Calendars"
+  screen in Settings. Give each a name, a colour, and an optional
+  description; rename, recolour, or delete them later. Useful when you want
+  a calendar without setting up an account
+- The Calendars screen also lists your synced calendars (DAVx5, ICSx5, …)
+  grouped by account, each with a "Manage" button that opens the app the
+  calendar actually comes from, plus an "Add account" shortcut to the
+  system account settings. Calendula never touches a synced calendar's
+  server itself — that stays with its own app
+
+### Changed
+- Colour swatches in the calendar editor now preview the soft, pastel tone
+  a calendar is actually drawn with, instead of a bright raw colour
+- The calendar editor reuses the event form's field and button styling for
+  a consistent look
+
+## [2.1.0] — 2026-06-15
+
+### Added
+- The month view now shows real events in each day instead of coloured
+  dots: all-day and multi-day events render as continuous bars at the top
+  (a multi-day event is one connected bar across the days it spans, not a
+  chip per day), with single-day timed events as filled pills beneath.
+  Up to three rows show per day, then a "+N" dot indicator for the rest.
+  Each day keeps a rounded surface background, matching the week and day
+  views; today is marked with a filled circle on its number
+- The slide-out panel now has a "View" section to switch between Month,
+  Week, and Day, mirroring the top-bar switcher pill — tapping a view
+  selects it and closes the drawer. The current view is highlighted
+
+### Fixed
+- Typing in the event title, location, and description fields no longer
+  makes the cursor jump around: the form state's round-trip to the UI was
+  hopping to a background dispatcher, so the text field saw a lagging value
+  while typing. Only the calendar/preferences reads stay off the main
+  thread now; the keystroke path is synchronous again
+
+## [2.0.0] — 2026-06-11
+
+### Added
+- Conflict handling when saving an edit: if the event changed elsewhere
+  (sync, another device) while the form was open, saving now asks whether
+  to keep or discard your changes instead of silently overwriting the
+  edited fields — and tells you when the event was deleted in the meantime.
+  "Keep" still writes only the fields you touched; external changes to
+  untouched fields survive either way
+- F-Droid store screenshots (German + English), captured with demo data
+
+### Changed
+- F-Droid description and README no longer claim the app is read-only —
+  they now describe write support and reminder delivery
+
+### Fixed
+- `versionName`/`versionCode` bumped to 2.0.0 / 13 — closing out the
+  write-support milestone (v1.1 through v2.0)
+
+## [1.4.0] — 2026-06-11
+
+### Added
+- Reminder notifications (v1.4): Calendula now delivers event reminders as
+  notifications itself — the system schedules them but posts nothing, so a
+  calendar app must (essential when Calendula is the only one installed).
+  Due reminders appear on a dedicated "Event reminders" channel; tapping one
+  opens the event's detail screen. Email reminders are never posted (the
+  provider only schedules alert-type reminders)
+- A one-time onboarding step after the calendar grant introduces reminders,
+  requests the notification permission (Android 13+), and warns that a second
+  calendar app with notifications on will duplicate them. "Not now" leaves
+  the feature off
+- Settings gained a "Notifications" section mirroring the choice: an event-
+  reminders toggle (default on) with the duplicate-reminders hint; turning it
+  on re-requests the notification permission when missing
+
+### Fixed
+- `versionName`/`versionCode` bumped to 1.4.0 / 12
+
+## [1.3.0] — 2026-06-11
+
+### Added
+- Event editing: a pencil action on the detail screen (writable calendars
+  only) opens the event form prefilled with the event. Only fields you
+  actually changed are written back; saving an untouched form is a no-op.
+  Sections holding data are always shown, regardless of the form-field
+  defaults; the calendar itself can't be changed while editing
+- Recurring events — scoped writes, chosen when saving (Google model):
+  "only this event" (a modified-occurrence exception), "this and all
+  following" (the series is split at the occurrence), or "all events in
+  the series". Changing the recurrence rule rules out "only this event"
+- Deleting a recurring event gained the middle option too: "this and all
+  following events" ends the series just before the chosen occurrence
+- Recurrence picker (create and edit): one-tap daily/weekly/monthly/yearly
+  presets plus a custom step with interval + unit, weekday toggles for
+  weekly rules ("every week on Mon and Fri"), and an end condition (never /
+  on a date / after a number of times). Rules the picker can't express
+  (e.g. "second Thursday monthly") are shown humanized and preserved
+  verbatim unless replaced. Recurrence also joined the optional form
+  fields and their settings defaults
+- Validation: a repeat that would end before the event starts is flagged
+  (it would otherwise vanish from every view)
+
+### Changed
+- Editing reminders reconciles against the provider's actual rows:
+  reminders you didn't touch keep their method (e.g. email reminders on
+  synced events survive unrelated edits)
+- The contextual WRITE_CALENDAR upgrade for v1.0 installs covers the edit
+  action like delete
+
+### Fixed
+- Splitting a series ("this and following") sends the complete time-column
+  set in one update, so the provider regenerates its cached instances — an
+  RRULE-only update left a stale duplicate of the tapped occurrence on the
+  split day
+- RRULE UNTIL values are written as the local end of day expressed in UTC
+  (instead of a flat `T235959Z`), so recurrences can't leak an extra day in
+  timezones ahead of UTC
+- `versionName`/`versionCode` bumped to 1.3.0 / 11
+
+## [1.2.1] — 2026-06-11
+
+### Added
+- Optional event-form fields with user-controlled defaults: reminders,
+  availability (busy/free), and visibility (default/public/private/
+  confidential) joined location and description as form sections. Settings
+  gained a "New event form" section choosing which show by default; the rest
+  unfold via a "More fields" picker
+- Reminders editor: stacked rows with right-bound remove, full-width add
+  action; the picker offers one-tap presets and a custom amount + unit
+  (minutes/hours/days/weeks) step
+- `OptionCard` — the app's standard selection-dialog row (full-width tonal
+  card, optional icon + supporting line, highlighted selection). All dialogs
+  (calendar, visibility, more-fields, reminder presets, recurring-delete)
+  now use it; radio-row dialogs are retired
+
+### Changed
+- Event form redesigned onto the detail screen's design system: tonal cards
+  with gutter icons (top-aligned on tall cards), borderless inline text
+  fields, calendar-coloured accent bar under the title, no dividers, no
+  top-bar title; placeholders render clearly fainter than input
+- M3 Expressive motion: the theme now provides a MotionScheme
+  (`MaterialExpressiveTheme`, standard springs — expressive bounce reviewed
+  as overdone), the FAB stack and "more fields" reveals animate on theme
+  springs
+- The jump-to-today slide is direction-aware (future → today slides in from
+  the left, past → from the right)
+- `versionName`/`versionCode` bumped to 1.2.1 / 10
+
+### Fixed
+- The keyboard no longer pans the whole event form; the screen stays
+  anchored and the focused field scrolls into view (`adjustResize` +
+  `imePadding`)
+
+## [1.2.0] — 2026-06-11
+
+### Added
+- Create events (milestone 2, slice 2):
+  - A "+" FAB on the month, week, and day views opens a new full-screen event
+    form, prefilled with the visible day (today at the next full hour, or
+    09:00 on other days)
+  - The form covers title, all-day toggle, start/end with Material 3 date and
+    time pickers (moving the start drags the end along, preserving duration),
+    target calendar, location, and description
+  - The calendar picker offers only writable calendars and preselects the one
+    you last created an event in
+  - Validation on save ("ends before it starts", no writable calendar), with
+    the same contextual write-permission upgrade as delete
+  - All-day events are stored provider-correctly (UTC midnights, exclusive
+    end), timed events in the device time zone
+
+### Changed
+- The jump-to-today pill now stacks above the new "+" FAB instead of being
+  the only floating action
+- `versionName`/`versionCode` bumped to 1.2.0 / 9
+
+## [1.1.0] — 2026-06-11
+
+### Added
+- Write foundation (milestone 2, slice 1): Calendula can now **delete events**.
+  - Delete action on the event detail screen, with a confirmation dialog;
+    recurring events choose between "Only this event" (a cancelled exception,
+    so the rest of the series survives) and "All events in the series"
+  - `WRITE_CALENDAR` permission: onboarding asks for read+write in one system
+    dialog, but only read access is required — declining write keeps the app
+    fully usable read-only. Existing v1.0 installs are asked for the write
+    upgrade in place, on their first delete
+  - Read-only calendars (WebCal subscriptions, birthday calendars, …) are
+    detected via `CALENDAR_ACCESS_LEVEL` and show no edit/delete actions at all
+
+### Changed
+- Onboarding copy no longer claims "read-only"; it now says your data stays on
+  the device (still no internet permission, still zero telemetry)
+- The placeholder Edit button on the detail screen (a no-op since v0.4) is
+  removed until editing ships in a later slice
+- `versionName`/`versionCode` bumped to 1.1.0 / 8
+
+## [1.0.0] — 2026-06-11
+
+First public release. Calendula is a read-only, Material 3 Expressive calendar
+that lives entirely on top of Android's `CalendarContract` — every calendar
+synced to the device (CalDAV via DAVx5, Google, local, WebCal, …) shows up
+automatically, with zero telemetry and no internet permission.
+
+### Highlights (accumulated across v0.1 → v0.6)
+- Month, week, and day views with a view switcher, swipe navigation, and
+  Loading / Failure / Success states on every screen
+- Full-screen event detail surfacing every readable `CalendarContract` field —
+  times, recurrence (humanised), location, description (with tappable links),
+  attendees + roles + your own response, reminders, status, availability,
+  access level, and foreign time zones
+- Per-calendar visibility filter (grouped by account, persisted) and a Settings
+  screen (theme, Material You dynamic colour, week start, app language)
+- Material 3 Expressive first-run onboarding for calendar access
+- German + English localization throughout
+
+### Changed
+- `versionName`/`versionCode` bumped to 1.0.0 / 7
+
+## [0.6.0] — 2026-06-11
+
+### Added
+- Full event read (v0.6): the detail screen now surfaces every readable
+  `CalendarContract` field that V1 had been dropping —
+  - **Reminders** — each configured lead time, humanised ("10 minutes before",
+    "1 day before", "At time of event"), read from `CalendarContract.Reminders`
+  - **Status** — Tentative / Cancelled chip under the title; a cancelled event
+    also strikes through its title (Confirmed shows no chip)
+  - **Availability** — a "Free" pill pinned top-right of the title when the
+    event doesn't block your time (`Events.AVAILABILITY`, the iCal TRANSP
+    field); the default "Busy" is left implicit to avoid noise on every event
+  - **Access level** — a Private / Confidential chip when the event isn't public
+  - **Attendee role** — organizer / optional / resource badge under each
+    attendee, plus the device user's own response ("Your response: …") from
+    `Events.SELF_ATTENDEE_STATUS`
+  - **Time zone** — shown only for timed events pinned to a zone other than the
+    device's, so cross-zone events read unambiguously
+  - **Linked URLs** — http(s) links in the description are now tappable
+- Domain model rounded out with `Reminder`, `EventStatus`, `Availability`,
+  `AccessLevel`, `AttendeeRelationship`, `AttendeeType`, and the attendee/self
+  status fields; mappers + unit tests cover every new column's integer codes
+
+### Changed
+- Redesigned the first-run grant-access screen — the onboarding a new user
+  sees. Material 3 Expressive layout: branded launcher-mark hero, an app-name
+  eyebrow, a benefit-led headline, three trust rows (on-device, every calendar,
+  no tracking) with tonal icon chips, a full-width filled CTA with a trailing
+  arrow, and a "Read-only · no internet permission" footnote (the app declares
+  only `READ_CALENDAR`). The denied/recovery state shares the same shell with a
+  lock-badged hero and Open-settings / Try-again actions
+- `versionName`/`versionCode` bumped to 0.6.0 / 6
+
+### Notes
+- A dedicated event **URL** field was dropped from scope: `CalendarContract`
+  has no `Events.URL` column (only `CUSTOM_APP_URI`, an app deep-link), so URLs
+  are surfaced by linkifying the description instead
+
+## [0.5.0] — 2026-06-10
+
+### Added
+- Calendar filter (M3): the navigation drawer now hosts the calendar list
+  inline — every calendar grouped by account, each with a colour swatch and a
+  visibility switch. Hiding a calendar is persisted app-side (DataStore,
+  separate from the system VISIBLE flag) and applied centrally in the
+  repository, so month/week/day re-filter live the moment a switch flips.
+  The drawer was trimmed to just Today, the calendar filter, and Settings
+  (the stubbed jump-to-date entry was removed; jump-to-date was later cut
+  from scope entirely)
+- Settings (M4): a full-screen destination with
+  - **Appearance** — theme (System / Light / Dark), Material You dynamic colour
+    (auto-disabled below Android 12), week start (Automatic / Monday / Sunday)
+  - **Language** — app language (System / Deutsch / English) via per-app
+    locales, persisted across cold starts down to Android 10
+  - **About** — version, license, and a link to the source on Gitea
+- Week-start preference now drives the month grid and week view; "Automatic"
+  follows the active locale (Monday in DE, Sunday in en-US)
+
+### Changed
+- Theme is driven by one activity-scoped settings source, so a theme or
+  dynamic-colour change applies app-wide immediately
+- `versionName`/`versionCode` bumped to 0.5.0 / 5 (the in-repo version had
+  lagged behind the release tags); the About screen reads it directly
+
+## [0.4.0] — 2026-06-10
+
+### Added
+- Event detail (S4): full-screen destination (MD3 list→detail, not a bottom
+  sheet) opened by tapping an event in the week/day timeline — title with a
+  calendar-colour accent line, a card per field (when, calendar, location,
+  description, attendees, recurrence) with leading icons, location tap opens a
+  maps intent, Loading/Failure/Success states, slide-in/out over the calendar
+- Human-readable recurrence: RRULE rendered as e.g. "Every week on _Tue_ and
+  _Thu_ until 31 Dec 2026" (FREQ/INTERVAL/BYDAY/UNTIL/COUNT, abbreviated +
+  italicised day names, localized list formatting), with a generic fallback
+- Month → day navigation: tapping a day cell opens the day view on that date
+
+### Fixed
+- Recurring events failed to open in the detail view: the series row stores
+  DURATION instead of DTEND, so the mapper dropped it (EventNotFound). The
+  detail now keeps such events and shows the tapped occurrence's own times
+  (from CalendarContract.Instances) instead of the series start
+
+## [0.3.0] — 2026-06-10
+
+### Added
+- Month view (S1): Material 3 Expressive card-per-day grid (only the current
+  month's weeks; neighbouring days left blank), per-day event dots with "+N"
+  overflow, today emphasised via `primaryContainer`, spring-based press
+  feedback from the active motion scheme, swipe + drawer navigation,
+  Loading/Failure/Success states
+- Week view (S2): vertical time schedule with overlap-resolved lanes,
+  separate all-day strip, midnight-spanning events clipped per day, swipe
+  navigation, Loading/Failure/Success states
+- Day view (S3): single-column slice of the week schedule reusing its
+  overlap-lane layout, per-day swipe navigation, noon-centred scroll that
+  persists across swipes, animated all-day strip, compact top bar with the
+  full date, Loading/Failure/Success states
+- Functional view-switcher (M1) cycling Month ↔ Week ↔ Day
+- Shared calendar UI building blocks in `ui/common/` (navigation drawer,
+  failure screen, view-switcher pill, color pastelizer, observable locale)
+
+### Removed
+- Throwaway debug screen — superseded by the month view
+
+## [0.2.1] — 2026-06-09
+
+### Changed
+- Regenerated the F-Droid catalog `icon.png` (512x512, both locales) so it
+  is pixel-faithful to the on-device adaptive launcher icon: same slate
+  background (`#5C6B7A`), off-white mark (`#FAF6F0`), and the foreground
+  group transform (`scale 0.5`, pivot `114,108`, translate `2,8`) baked in.
+- Added `design/icon/calendula_launcher.svg` — the composed full-bleed
+  icon (background + transformed mark) as the single source of truth for
+  store/F-Droid renders.
 
 ## [0.2.0] — 2026-06-08
 
@@ -19,6 +748,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Unit-Tests für Cursor-Mapping (alle §8-Defensiv-Cases), Repository-Flows mit Turbine, DataStore round-trip
 - Instrumented smoke test against the real CalendarContract provider
 
+### Changed
+- Redesigned launcher icon: line-art calendar with a stylized "1" inside
+  (kalendae reference) and a small calendula bloom badge in the
+  bottom-right corner. Replaces the simple "1"-only foreground from
+  v0.1.0. Source SVG checked in at `design/icon/calendula_mark.svg`,
+  also used to regenerate the F-Droid catalog `icon.png` (512x512)
+  per locale.
+
 ## [0.1.1] — 2026-06-08
 
 ### Fixed
@@ -51,3 +788,25 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Gitea release workflow: signed release APK + F-Droid metadata sync to Hetzner
 - F-Droid metadata stubs (DE + EN short/full descriptions)
 - `.planning/` project-tracking documents
+
+[#1]: https://codeberg.org/jlmakiola/calendula/issues/1
+[#2]: https://codeberg.org/jlmakiola/calendula/issues/2
+[#3]: https://codeberg.org/jlmakiola/calendula/issues/3
+[#4]: https://codeberg.org/jlmakiola/calendula/issues/4
+[#5]: https://codeberg.org/jlmakiola/calendula/issues/5
+[#6]: https://codeberg.org/jlmakiola/calendula/issues/6
+[#7]: https://codeberg.org/jlmakiola/calendula/issues/7
+[#8]: https://codeberg.org/jlmakiola/calendula/issues/8
+[#9]: https://codeberg.org/jlmakiola/calendula/issues/9
+[#10]: https://codeberg.org/jlmakiola/calendula/issues/10
+[#12]: https://codeberg.org/jlmakiola/calendula/issues/12
+[#13]: https://codeberg.org/jlmakiola/calendula/issues/13
+[#14]: https://codeberg.org/jlmakiola/calendula/issues/14
+[#15]: https://codeberg.org/jlmakiola/calendula/issues/15
+[#16]: https://codeberg.org/jlmakiola/calendula/issues/16
+[#17]: https://codeberg.org/jlmakiola/calendula/issues/17
+[#18]: https://codeberg.org/jlmakiola/calendula/issues/18
+[#19]: https://codeberg.org/jlmakiola/calendula/issues/19
+[#20]: https://codeberg.org/jlmakiola/calendula/issues/20
+[#24]: https://codeberg.org/jlmakiola/calendula/issues/24
+[#29]: https://codeberg.org/jlmakiola/calendula/issues/29

README.md

@@ -1,43 +1,125 @@
-# Calendula
+<div align="center">
 
-A modern Material 3 Expressive calendar app for Android.
+<img src="fastlane/metadata/android/en-US/images/icon.png" width="112" alt="Calendula icon">
 
-Calendula is named after the flower of the same name, whose name comes from
-the Latin *kalendae* — the first day of the month — the same root as the
-word "calendar". Calendula reads from Android's built-in `CalendarContract`,
-so any calendar source synced to your device (CalDAV via DAVx5, Google,
-local, WebCal subscriptions, ...) is shown.
+<h1>Calendula</h1>
 
-## Features (V1)
+<p><strong>A modern Material 3 Expressive calendar for Android.</strong><br>
+Reads, writes, and reminds — on top of the system calendar, with zero network access.</p>
 
-- Month, Week, and Day views
-- Read-only event details (write support comes in V2)
-- Multi-calendar visibility toggle
-- Material You Dynamic Color (Android 12+)
-- Light/Dark theme follows system
-- German + English UI
+<p>
+<a href="https://gitea.jeanlucmakiola.de/makiolaj/calendula/actions"><img src="https://gitea.jeanlucmakiola.de/makiolaj/calendula/actions/workflows/ci.yaml/badge.svg?branch=main" alt="CI"></a>
+<img src="https://img.shields.io/badge/Android-10%2B-3DDC84?logo=android&logoColor=white" alt="Android 10+">
+<img src="https://img.shields.io/badge/Kotlin-Compose-7F52FF?logo=kotlin&logoColor=white" alt="Kotlin + Compose">
+<img src="https://img.shields.io/badge/Material%203-Expressive-4285F4" alt="Material 3 Expressive">
+<a href="LICENSE"><img src="https://img.shields.io/badge/License-MIT-green" alt="MIT License"></a>
+</p>
 
-## Building
+<p>
+<a href="https://f-droid.org/packages/de.jeanlucmakiola.calendula/"><img src="https://fdroid.gitlab.io/artwork/badge/get-it-on.png" alt="Get it on F-Droid" height="56"></a>
+&nbsp;
+<a href="https://ko-fi.com/jeanlucmakiola"><img src="https://storage.ko-fi.com/cdn/brandasset/v2/support_me_on_kofi_badge_beige.png" alt="Support me on Ko-fi" height="56"></a>
+</p>
 
-Requires Android SDK 36 and JDK 17. The Gradle wrapper is checked in, so no host Gradle install is needed:
+<p>
+<img src="fastlane/metadata/android/en-US/images/phoneScreenshots/01-week.png" width="19%" alt="Week view">&nbsp;
+<img src="fastlane/metadata/android/en-US/images/phoneScreenshots/02-month.png" width="19%" alt="Month view">&nbsp;
+<img src="fastlane/metadata/android/en-US/images/phoneScreenshots/04-detail.png" width="19%" alt="Event detail">&nbsp;
+<img src="fastlane/metadata/android/en-US/images/phoneScreenshots/05-edit.png" width="19%" alt="Event form">&nbsp;
+<img src="fastlane/metadata/android/en-US/images/phoneScreenshots/06-onboarding.png" width="19%" alt="Reminder onboarding">
+</p>
 
-```bash
-# Build debug APK
-./gradlew assembleDebug
+</div>
 
-# Run unit tests
-./gradlew test
+Calendula is named after the flower whose name — like the word *calendar* —
+comes from the Latin *kalendae*, the first day of the month. It lives
+entirely on top of Android's `CalendarContract`: any calendar synced to your
+device (CalDAV via DAVx5, Google, local, WebCal subscriptions, …) simply
+appears, and everything you create or edit syncs back the same way. No own
+database, no sync stack reinvented.
 
-# Run lint
-./gradlew lint
-```
+## ✨ Features
 
-If your default JDK is something other than 17, set `JAVA_HOME` explicitly:
+**Calendar**
 
-```bash
-JAVA_HOME=/path/to/jdk-17 ./gradlew assembleDebug
-```
+- Month, week, and day views with a one-tap view switcher
+- Full event details — attendees and their responses, reminders, recurrence
+  (humanized), availability, visibility, foreign time zones
+- Per-calendar visibility toggle, grouped by account
 
-## License
+**Editing**
+
+- Create, edit, and delete events — including recurring events with scoped
+  writes: *only this event*, *this and all following*, or *the whole series*
+- Recurrence picker with one-tap presets and custom rules (interval, weekday
+  toggles, end conditions); rules it can't express are preserved verbatim
+- Conflict-safe saves: if an event changed elsewhere while you were editing,
+  Calendula asks instead of silently overwriting
+- Read-only calendars (WebCal, birthdays) are detected and respected
+
+**Reminders**
+
+- Event reminders delivered by Calendula itself as notifications —
+  essential when it's your only calendar app, since Android delegates
+  reminder delivery to calendar apps
+- Tap a reminder to land on the event
+
+**Design & privacy**
+
+- Real Material 3 Expressive throughout — dynamic color (Android 12+),
+  expressive motion and shapes, light/dark theme
+- German and English UI, per-app language setting — and [open to community
+  translations](#-translations)
+- **Zero telemetry, zero analytics, no internet permission** — your data
+  never leaves the device
+
+## 📦 Install
+
+### F-Droid (recommended)
+
+Calendula is on the **official [F-Droid](https://f-droid.org) repository** —
+just search for **Calendula** in any F-Droid client, or
+[install it from f-droid.org](https://f-droid.org/packages/de.jeanlucmakiola.calendula/).
+
+### Self-hosted repo (latest builds)
+
+New versions are built, signed, and published to a self-hosted repository the
+moment each tag lands — usually a few days ahead of the official repo, which
+rebuilds on F-Droid's own schedule. Add it for the freshest builds:
+
+1. In your F-Droid client, open *Settings → Repositories → Add* (or open the
+   link below on your phone):
+
+   ```
+   https://apps.dev.jeanlucmakiola.de/dev/fdroid/repo?fingerprint=C2C0640402BF458FC0ED957AF0B37AA4C14022E72F89CE90B5965B458CF73425
+   ```
+
+   <sub>Repo: `https://apps.dev.jeanlucmakiola.de/dev/fdroid/repo` ·
+   fingerprint (SHA-256):
+   `C2C0 6404 02BF 458F C0ED 957A F0B3 7AA4 C140 22E7 2F89 CE90 B596 5B45 8CF7 3425`</sub>
+
+2. Refresh, search for **Calendula**, install.
+
+Both channels share the same signing key, so you can switch between them
+without reinstalling. Or build from source — see below.
+
+## 📚 Documentation
+
+- **[Building from source](docs/BUILDING.md)** — requirements and Gradle tasks
+- **[Architecture](docs/ARCHITECTURE.md)** — the layered design and key pipelines
+- **[Roadmap](.planning/ROADMAP.md)** — what's shipped and what's next
+
+## 🌍 Translations
+
+Calendula ships in German and English, and you're warmly invited to add your
+language. Translations are managed on a self-hosted **Weblate**:
+
+**→ [Help translate Calendula](https://weblate.dev.jeanlucmakiola.de/engage/calendula/)**
+
+No coding needed — register on the Weblate server, pick (or request) a language,
+and translate the strings in your browser. You can also reach this link in the
+app from the top of **Settings → App language**.
+
+## 📜 License
 
 [MIT](LICENSE) — Jean-Luc Makiola, 2026

app/build.gradle.kts

@@ -23,8 +23,13 @@ android {
         applicationId = "de.jeanlucmakiola.calendula"
         minSdk = 29
         targetSdk = 36
-        versionCode = 1
-        versionName = "0.1.0"
+        // These committed values ARE the source of truth for a release: merging
+        // a bumped versionName into main triggers .gitea/workflows/release.yaml,
+        // which builds this version and then creates the matching vX.Y.Z tag +
+        // release itself (versionCode is pinned to MAJOR*10000 + MINOR*100 +
+        // PATCH from versionName, e.g. 2.7.2 -> 20702). See docs/RELEASING.md.
+        versionCode = 21300
+        versionName = "2.13.0"
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
     }
@@ -42,6 +47,11 @@ android {
 
     buildTypes {
         release {
+            // Keep release builds reproducible for F-Droid: don't let AGP embed
+            // build-environment git metadata (META-INF/version-control-info.textproto),
+            // whose `revision`/path content varies by build machine and is the only
+            // thing that otherwise differs from a clean from-source rebuild.
+            vcsInfo { include = false }
             isMinifyEnabled = true
             isShrinkResources = true
             proguardFiles(
@@ -56,6 +66,21 @@ android {
             applicationIdSuffix = ".debug"
             isMinifyEnabled = false
         }
+        // A locally-installable twin of `release`: same R8 shrinking + obfuscation
+        // and resource shrinking, but debug-signed and given its own applicationId
+        // suffix so it installs alongside both the production app (signed with the
+        // real key) and the debug build. Used to smoke-test a release candidate on
+        // a real device before tagging — R8-only breakage and first-run/permission
+        // states don't surface in the unminified debug build, nor on a device that
+        // already holds the permission. Never published. See docs/RELEASING.md.
+        create("releaseTest") {
+            initWith(getByName("release"))
+            applicationIdSuffix = ".releasetest"
+            signingConfig = signingConfigs.getByName("debug")
+            isMinifyEnabled = true
+            isShrinkResources = true
+            matchingFallbacks += "release"
+        }
     }
 
     compileOptions {
@@ -65,6 +90,18 @@ android {
 
     buildFeatures {
         compose = true
+        // BuildConfig.DEBUG gates the in-app debug ribbon (see DebugRibbon).
+        buildConfig = true
+    }
+
+    // Don't embed AGP's dependency-metadata block in the APK signing block. It's
+    // a Play-oriented blob, and F-Droid's reproducible-build scanner rejects any
+    // "extra signing block" — so leaving it in blocks publishing to the official
+    // repo. It lives in the signing block, not the zip entries, so disabling it
+    // doesn't change the build output (reproducibility is unaffected).
+    dependenciesInfo {
+        includeInApk = false
+        includeInBundle = false
     }
 
     packaging {
@@ -73,6 +110,15 @@ android {
         }
     }
 
+    lint {
+        // Community translations are expected to be partial — a missing string
+        // falls back to the English base at runtime — so don't fail the build on
+        // it. Stale/extra keys (ExtraTranslation) stay fatal; scripts/
+        // check_translations.py guards the same invariants with clearer,
+        // translator-facing messages.
+        informational += "MissingTranslation"
+    }
+
     testOptions {
         unitTests {
             all { it.useJUnitPlatform() }
@@ -89,6 +135,7 @@ kotlin {
 
 dependencies {
     implementation(libs.androidx.core.ktx)
+    implementation(libs.androidx.appcompat)
     implementation(libs.androidx.lifecycle.runtime.ktx)
     implementation(libs.androidx.lifecycle.runtime.compose)
     implementation(libs.androidx.activity.compose)
@@ -98,6 +145,8 @@ dependencies {
     implementation(libs.androidx.ui.graphics)
     implementation(libs.androidx.ui.tooling.preview)
     implementation(libs.androidx.material3)
+    implementation(libs.androidx.compose.material.icons.core)
+    implementation(libs.androidx.compose.material.icons.extended)
 
     implementation(libs.hilt.android)
     implementation(libs.androidx.hilt.navigation.compose)
@@ -105,6 +154,12 @@ dependencies {
 
     implementation(libs.androidx.datastore.preferences)
 
+    implementation(libs.androidx.work.runtime.ktx)
+    implementation(libs.androidx.documentfile)
+
+    implementation(libs.androidx.glance.appwidget)
+    implementation(libs.androidx.glance.material3)
+
     implementation(libs.kotlinx.datetime)
     implementation(libs.kotlinx.coroutines.core)
 

app/proguard-rules.pro

@@ -4,3 +4,37 @@
 
 # Compose Compiler may keep its own; defaults are fine
 -dontwarn org.jetbrains.annotations.**
+
+# Room database implementations (pulled in transitively via
+# androidx.glance:glance-appwidget → androidx.work → androidx.room).
+# The widgets rely on Glance, whose WorkManager backend stores state in a Room
+# database. Under R8 full mode (AGP 9 default) the generated *_Impl subclasses
+# of RoomDatabase lose their usable no-arg constructor / are marked abstract,
+# so Room's reflective instantiation throws InstantiationException and the app
+# crashes at startup with "Failed to create an instance of ...WorkDatabase".
+# Keep the generated Room database implementations fully intact.
+-keep class * extends androidx.room.RoomDatabase { *; }
+-dontwarn androidx.room.paging.**
+
+# Glance runs an @Composable's `actionRunCallback<T>()` by persisting the
+# callback's fully-qualified class name into the click PendingIntent, then
+# reflectively instantiating it (Class.forName(name).newInstance()) when the tap
+# fires. Under R8 full mode (AGP 9 default) these ActionCallback classes — only
+# ever referenced reflectively — get renamed or have their no-arg constructor
+# stripped, so the lookup fails silently and the tap does nothing. In the month
+# and agenda widgets that broke every run-callback control (the prev/next/today
+# month arrows and the agenda refresh) in release builds while actionStartActivity
+# taps, which ride a PendingIntent and need no reflection, kept working. Keep
+# every ActionCallback's name and constructor intact.
+-keep class * implements androidx.glance.appwidget.action.ActionCallback { <init>(...); }
+
+# WorkManager instantiates an InputMerger reflectively (Class.newInstance) from
+# the fully-qualified class name persisted in the WorkSpec, so the class must
+# keep both its name and a no-arg constructor. Glance renders every widget
+# through a WorkManager worker (androidx.glance.session.SessionWorker) whose
+# default merger is androidx.work.OverwritingInputMerger. Under R8 full mode
+# (AGP 9 default) that unused no-arg constructor was stripped, so WorkManager
+# threw "OverwritingInputMerger has no zero argument constructor", the
+# SessionWorker never ran, and widgets were stuck on their loading layout
+# (a blank spinner) in release builds. Keep every InputMerger's name + ctor.
+-keep class * extends androidx.work.InputMerger { <init>(...); }

app/src/androidTest/java/de/jeanlucmakiola/calendula/data/calendar/CalendarRepositorySmokeTest.kt

@@ -1,10 +1,14 @@
 package de.jeanlucmakiola.calendula.data.calendar
 
 import android.Manifest
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.PreferenceDataStoreFactory
+import androidx.datastore.preferences.core.Preferences
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import androidx.test.platform.app.InstrumentationRegistry
 import androidx.test.rule.GrantPermissionRule
 import com.google.common.truth.Truth.assertThat
+import de.jeanlucmakiola.calendula.data.prefs.CalendarPrefs
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.runBlocking
@@ -24,7 +28,10 @@ class CalendarRepositorySmokeTest {
 
     private fun newRepo(): CalendarRepositoryImpl {
         val dataSource = AndroidCalendarDataSource(context)
-        return CalendarRepositoryImpl(dataSource, Dispatchers.IO)
+        val store: DataStore<Preferences> = PreferenceDataStoreFactory.create(
+            produceFile = { context.cacheDir.resolve("smoke_test_prefs.preferences_pb") },
+        )
+        return CalendarRepositoryImpl(dataSource, CalendarPrefs(store), Dispatchers.IO)
     }
 
     @Test

app/src/debug/res/values/colors.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+    Debug-only launcher-icon background. Production is slate (#5C6B7A); the
+    debug build paints the adaptive-icon background burnt orange instead, so the
+    debug icon reads at a glance as "not the real app" on the home screen. The
+    off-white foreground mark contrasts on both. See drawable/ic_launcher_background.
+-->
+<resources>
+    <color name="ic_launcher_background">#FFB23B00</color>
+</resources>

app/src/debug/res/values/strings.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+    Debug-build resource overrides. Merged on top of src/main for the `debug`
+    build type only (release/releaseTest keep the production values), so the
+    debug app is unmistakable on the launcher: its own label, alongside the
+    real app thanks to the `.debug` applicationId suffix.
+-->
+<resources>
+    <string name="app_name">Calendula Debug</string>
+</resources>

app/src/main/AndroidManifest.xml

@@ -3,26 +3,233 @@
     xmlns:tools="http://schemas.android.com/tools">
 
     <uses-permission android:name="android.permission.READ_CALENDAR" />
+    <uses-permission android:name="android.permission.WRITE_CALENDAR" />
+    <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
+    <!--
+      Optional and feature-gated: only the "Contact special dates" feature reads
+      contacts, and only after the user enables it and grants this at runtime
+      (never requested at startup). Everything stays offline — birthdays and
+      other contact dates are mirrored one-way into local calendars; contacts
+      are never written and nothing leaves the device (the app has no INTERNET
+      permission). See docs/design/contact-special-dates.md.
+    -->
+    <uses-permission android:name="android.permission.READ_CONTACTS" />
+    <!--
+      Lets the "Reliable delivery" setting open the direct system dialog to
+      exempt Calendula from battery optimisation (so reminder broadcasts aren't
+      delayed by Doze). Used only to launch that dialog; falls back to the
+      battery-optimisation list if the OS declines the direct intent.
+    -->
+    <uses-permission android:name="android.permission.REQUEST_IGNORE_BATTERY_OPTIMIZATIONS" />
+
+    <!--
+      Re-fire a snoozed reminder at an exact time (the calendar provider won't —
+      its alert is already fired). USE_EXACT_ALARM is auto-granted to calendar
+      apps on API 33+; SCHEDULE_EXACT_ALARM covers API 31–32 (user-revocable,
+      with an inexact fallback if withheld). F-Droid-clean: no Play allowlisting.
+    -->
+    <uses-permission
+        android:name="android.permission.SCHEDULE_EXACT_ALARM"
+        android:maxSdkVersion="32" />
+    <uses-permission android:name="android.permission.USE_EXACT_ALARM" />
+
+    <!-- Package visibility (Android 11+): without this, getLaunchIntentForPackage
+         returns null and the calendar manager's per-account "manage" button can't
+         open the source sync app (DAVx5, ICSx5, Google Calendar, …). The LAUNCHER
+         intent makes launchable apps visible so we can launch whichever app owns a
+         calendar account's authenticator. -->
+    <queries>
+        <intent>
+            <action android:name="android.intent.action.MAIN" />
+            <category android:name="android.intent.category.LAUNCHER" />
+        </intent>
+    </queries>
 
     <application
         android:name=".CalendulaApp"
         android:allowBackup="true"
+        android:enableOnBackInvokedCallback="true"
         android:dataExtractionRules="@xml/data_extraction_rules"
         android:fullBackupContent="@xml/backup_rules"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"
+        android:localeConfig="@xml/locales_config"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
         android:theme="@style/Theme.Calendula"
         tools:targetApi="35">
         <activity
             android:name=".MainActivity"
-            android:exported="true">
+            android:exported="true"
+            android:launchMode="singleTop"
+            android:windowSoftInputMode="adjustResize">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
+
+            <!-- Be selectable as the system calendar app. Android has no API for
+                 an app to make itself the default, so registering the filters
+                 launchers and the OS use is what lets the user pick Calendula
+                 from the system chooser when a date action fires (issue #9).
+                 APP_CALENDAR is the "open the calendar app" action; the VIEW
+                 filters below catch a tapped date. -->
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <category android:name="android.intent.category.APP_CALENDAR" />
+            </intent-filter>
+            <!-- A launcher/clock date tap fires ACTION_VIEW on the provider's
+                 time Uri (content://com.android.calendar/time/<epochMillis>);
+                 some surfaces use the time/epoch mime type. We open the day view
+                 on that date (MainActivity.calendarTimeDateOrNull). -->
+            <intent-filter>
+                <action android:name="android.intent.action.VIEW" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <data
+                    android:scheme="content"
+                    android:host="com.android.calendar"
+                    android:pathPrefix="/time" />
+            </intent-filter>
+            <intent-filter>
+                <action android:name="android.intent.action.VIEW" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <data android:mimeType="time/epoch" />
+            </intent-filter>
+
+            <!-- Open a .ics file (file manager / email attachment / browser). -->
+            <intent-filter>
+                <action android:name="android.intent.action.VIEW" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <category android:name="android.intent.category.BROWSABLE" />
+                <data android:scheme="content" android:mimeType="text/calendar" />
+                <data android:scheme="file" android:mimeType="text/calendar" />
+            </intent-filter>
+            <!-- Receive a .ics shared from another app. -->
+            <intent-filter>
+                <action android:name="android.intent.action.SEND" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <data android:mimeType="text/calendar" />
+            </intent-filter>
+
+            <!-- Launcher long-press shortcuts (e.g. "New event"). -->
+            <meta-data
+                android:name="android.app.shortcuts"
+                android:resource="@xml/shortcuts" />
         </activity>
+
+        <!-- Standalone surface for a captured crash report. MainActivity routes
+             here on a startup crash-loop, so it stays clear of the app's Hilt
+             graph and Compose content. Not exported: launched only by us. -->
+        <activity
+            android:name=".ui.crash.CrashReportActivity"
+            android:exported="false"
+            android:excludeFromRecents="true"
+            android:launchMode="singleTask" />
+
+        <!-- Quick Settings tile: a one-tap "New event" shortcut in the QS panel.
+             Exported with BIND_QUICK_SETTINGS_TILE so only the system QS host can
+             bind it; the action mirrors the launcher "New event" shortcut. -->
+        <service
+            android:name=".qs.NewEventTileService"
+            android:exported="true"
+            android:icon="@drawable/ic_qs_new_event"
+            android:label="@string/qs_tile_new_event_label"
+            android:permission="android.permission.BIND_QUICK_SETTINGS_TILE">
+            <intent-filter>
+                <action android:name="android.service.quicksettings.action.QS_TILE" />
+            </intent-filter>
+        </service>
+
+        <!-- The provider broadcasts EVENT_REMINDER at reminder time but posts
+             no notification itself — a calendar app must (v1.4, Etar model).
+             Exported: the broadcast arrives from the provider's process. -->
+        <receiver
+            android:name=".data.reminders.EventReminderReceiver"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.EVENT_REMINDER" />
+                <data
+                    android:host="com.android.calendar"
+                    android:scheme="content" />
+            </intent-filter>
+        </receiver>
+
+        <!-- Snooze / dismiss actions on a reminder notification, plus the snooze
+             re-show alarm. Not exported: only our own notification buttons and
+             AlarmManager PendingIntents target it. -->
+        <receiver
+            android:name=".data.reminders.ReminderActionReceiver"
+            android:exported="false" />
+
+        <!-- Home-screen widgets (Glance). Exported: the launcher/host binds them. -->
+        <receiver
+            android:name=".widget.agenda.AgendaWidgetReceiver"
+            android:label="@string/widget_agenda_label"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
+            </intent-filter>
+            <meta-data
+                android:name="android.appwidget.provider"
+                android:resource="@xml/appwidget_info_agenda" />
+        </receiver>
+
+        <receiver
+            android:name=".widget.month.MonthWidgetReceiver"
+            android:label="@string/widget_month_label"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
+            </intent-filter>
+            <meta-data
+                android:name="android.appwidget.provider"
+                android:resource="@xml/appwidget_info_month" />
+        </receiver>
+
+        <!-- Keeps both widgets fresh: the calendar provider broadcasts
+             PROVIDER_CHANGED on any data change (our writes and external sync),
+             and the system broadcasts the date/time ones at midnight / clock
+             changes so "today" highlighting rolls over. -->
+        <receiver
+            android:name=".widget.WidgetUpdateReceiver"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.PROVIDER_CHANGED" />
+                <data
+                    android:host="com.android.calendar"
+                    android:scheme="content" />
+            </intent-filter>
+            <intent-filter>
+                <action android:name="android.intent.action.DATE_CHANGED" />
+                <action android:name="android.intent.action.TIME_SET" />
+                <action android:name="android.intent.action.TIMEZONE_CHANGED" />
+            </intent-filter>
+        </receiver>
+
+        <!-- Hands .ics files we stage in the cache to other apps via a content
+             Uri (single-event share). Authority tracks applicationId so the
+             debug suffix doesn't break getUriForFile. -->
+        <provider
+            android:name="androidx.core.content.FileProvider"
+            android:authorities="${applicationId}.fileprovider"
+            android:exported="false"
+            android:grantUriPermissions="true">
+            <meta-data
+                android:name="android.support.FILE_PROVIDER_PATHS"
+                android:resource="@xml/file_paths" />
+        </provider>
+
+        <!-- Persists the per-app language (M4) on API < 33, where the platform
+             per-app-languages API is unavailable. On 33+ this is a no-op. -->
+        <service
+            android:name="androidx.appcompat.app.AppLocalesMetadataHolderService"
+            android:enabled="false"
+            android:exported="false">
+            <meta-data
+                android:name="autoStoreLocales"
+                android:value="true" />
+        </service>
     </application>
 
 </manifest>

app/src/main/java/de/jeanlucmakiola/calendula/CalendulaApp.kt

@@ -1,11 +1,67 @@
 package de.jeanlucmakiola.calendula
 
 import android.app.Application
+import dagger.hilt.android.EntryPointAccessors
 import dagger.hilt.android.HiltAndroidApp
+import de.jeanlucmakiola.calendula.data.backup.BackupScheduler
+import de.jeanlucmakiola.calendula.data.backup.BackupWorker
+import de.jeanlucmakiola.calendula.data.contacts.SpecialDatesScheduler
+import de.jeanlucmakiola.calendula.data.contacts.SpecialDatesSyncWorker
+import de.jeanlucmakiola.calendula.data.crash.CrashReporter
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.launch
 
 /**
  * Application entry point. Registered as android:name=".CalendulaApp"
  * in AndroidManifest.xml. Hilt initializes its component graph here.
  */
 @HiltAndroidApp
-class CalendulaApp : Application()
+class CalendulaApp : Application() {
+
+    override fun onCreate() {
+        super.onCreate()
+        // Install first thing so startup crashes are captured too (privacy-
+        // respecting, on-device; the user submits the report by hand).
+        CrashReporter.install(this)
+        reconcileAutoBackup()
+        reconcileSpecialDates()
+    }
+
+    /**
+     * Bring the scheduled auto-backup work back in line with the saved settings
+     * on every launch — re-arms it after a reinstall and, crucially, cancels any
+     * orphaned work once backup has been turned off.
+     */
+    private fun reconcileAutoBackup() {
+        val deps = EntryPointAccessors.fromApplication(this, BackupWorker.Deps::class.java)
+        CoroutineScope(SupervisorJob() + Dispatchers.Default).launch {
+            val prefs = deps.settingsPrefs()
+            BackupScheduler.apply(
+                context = this@CalendulaApp,
+                enabled = prefs.autoBackupEnabled.first(),
+                intervalMinutes = prefs.autoBackupIntervalMinutes.first(),
+                hasFolder = prefs.autoBackupFolderUri.first() != null,
+            )
+        }
+    }
+
+    /**
+     * Re-arm (or cancel) the daily special-dates reconcile from the saved
+     * settings on every launch — like [reconcileAutoBackup], this cancels
+     * orphaned work after the feature is turned off and re-schedules after a
+     * reinstall. The foreground trigger (RootScreen ON_RESUME) does the on-open
+     * refresh, so no immediate run is needed here.
+     */
+    private fun reconcileSpecialDates() {
+        val deps = EntryPointAccessors.fromApplication(this, SpecialDatesSyncWorker.Deps::class.java)
+        CoroutineScope(SupervisorJob() + Dispatchers.Default).launch {
+            SpecialDatesScheduler.apply(
+                context = this@CalendulaApp,
+                enabled = deps.settingsPrefs().specialDatesEnabled.first(),
+            )
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/MainActivity.kt

@@ -1,24 +1,351 @@
 package de.jeanlucmakiola.calendula
 
+import android.content.Context
+import android.content.Intent
+import android.net.Uri
 import android.os.Bundle
-import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
+import androidx.appcompat.app.AppCompatActivity
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.core.content.IntentCompat
+import androidx.core.net.toUri
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import dagger.hilt.android.AndroidEntryPoint
+import de.jeanlucmakiola.calendula.data.crash.CrashReporter
+import de.jeanlucmakiola.calendula.data.prefs.ThemeMode
+import de.jeanlucmakiola.calendula.data.prefs.is24Hour
 import de.jeanlucmakiola.calendula.ui.RootScreen
+import de.jeanlucmakiola.calendula.ui.common.LocalShowHourLines
+import de.jeanlucmakiola.calendula.ui.common.LocalUse24HourFormat
+import de.jeanlucmakiola.calendula.ui.WidgetNavRequest
+import de.jeanlucmakiola.calendula.ui.common.CalendarView
+import de.jeanlucmakiola.calendula.ui.common.DebugRibbon
+import de.jeanlucmakiola.calendula.ui.crash.CrashReportActivity
+import de.jeanlucmakiola.calendula.ui.crash.CrashReportDialog
+import de.jeanlucmakiola.calendula.ui.crash.submitCrashReport
+import de.jeanlucmakiola.calendula.domain.FontRole
+import de.jeanlucmakiola.calendula.ui.settings.SettingsViewModel
 import de.jeanlucmakiola.calendula.ui.theme.CalendulaTheme
+import de.jeanlucmakiola.calendula.ui.theme.calendulaTypography
+import de.jeanlucmakiola.calendula.ui.theme.resolveFontFamily
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Instant
 
 @AndroidEntryPoint
-class MainActivity : ComponentActivity() {
+class MainActivity : AppCompatActivity() {
+
+    // The occurrence a reminder notification was tapped for (eventId, begin,
+    // end — the detail screen's key shape). singleTop + onNewIntent route a
+    // tap into the running activity; CalendarHost consumes and clears it.
+    private var requestedDetailKey by mutableStateOf<LongArray?>(null)
+
+    // A navigation a home-screen widget asked for (open a date / start a
+    // create). Consumed once by CalendarHost, same pattern as the detail key.
+    private var requestedNav by mutableStateOf<WidgetNavRequest?>(null)
+
+    // An .ics file opened/shared into the app (ACTION_VIEW/SEND). Consumed once
+    // by CalendarHost's import flow.
+    private var requestedImportUri by mutableStateOf<Uri?>(null)
+
+    // A captured crash report awaiting the user's decision, surfaced as a dialog
+    // over the calendar on the next launch (the single-crash path). A startup
+    // crash-loop is handled out of band, before setContent — see below.
+    private var pendingCrashReport by mutableStateOf<String?>(null)
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
-        enableEdgeToEdge()
-        setContent {
-            CalendulaTheme {
-                RootScreen(modifier = Modifier.fillMaxSize())
+
+        // If the app keeps crashing as it starts, the main UI can't be trusted
+        // to come up — route to the standalone report screen instead of
+        // re-entering the crashing graph.
+        if (CrashReporter.isCrashLoop(this)) {
+            startActivity(
+                Intent(this, CrashReportActivity::class.java)
+                    .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK),
+            )
+            finish()
+            return
         }
+
+        enableEdgeToEdge()
+        requestedDetailKey = intent.detailKeyOrNull()
+        requestedNav = intent.navRequestOrNull()
+        requestedImportUri = intent.importUriOrNull()
+        if (CrashReporter.shouldPrompt(this)) pendingCrashReport = CrashReporter.pendingReport(this)
+        setContent {
+            // One activity-scoped SettingsViewModel drives both the theme here
+            // and the Settings screen, so a theme change applies app-wide at once.
+            val settingsViewModel: SettingsViewModel = hiltViewModel()
+            val settings by settingsViewModel.state.collectAsStateWithLifecycle()
+            val darkTheme = when (settings.themeMode) {
+                ThemeMode.SYSTEM -> isSystemInDarkTheme()
+                ThemeMode.LIGHT -> false
+                ThemeMode.DARK -> true
+            }
+            // The app-wide clock convention: the time-format preference resolved
+            // against the device's 24-hour system setting, provided once here so
+            // every time label reads it via LocalUse24HourFormat.
+            val context = LocalContext.current
+            val use24Hour = remember(settings.timeFormat, context) {
+                settings.timeFormat.is24Hour(android.text.format.DateFormat.is24HourFormat(context))
+            }
+            // The user's custom-font choice, resolved to a Material typography
+            // (issue #19). Recomputed only when a token — or the custom-font
+            // re-import stamp AppFontSettings carries, so replacing the file
+            // behind an active "custom" token still refreshes — changes;
+            // "system for both" returns the default scale untouched.
+            val fonts by settingsViewModel.fontState.collectAsStateWithLifecycle()
+            val typography = remember(fonts, context) {
+                calendulaTypography(
+                    brand = resolveFontFamily(fonts.brand, FontRole.BRAND, context),
+                    plain = resolveFontFamily(fonts.plain, FontRole.PLAIN, context),
+                )
+            }
+            CalendulaTheme(
+                darkTheme = darkTheme,
+                dynamicColor = settings.dynamicColor,
+                typography = typography,
+            ) {
+                Box(modifier = Modifier.fillMaxSize()) {
+                    CompositionLocalProvider(
+                        LocalUse24HourFormat provides use24Hour,
+                        LocalShowHourLines provides settings.showHourLines,
+                    ) {
+                        RootScreen(
+                            modifier = Modifier.fillMaxSize(),
+                            requestedDetailKey = requestedDetailKey,
+                            onDetailKeyConsumed = { requestedDetailKey = null },
+                            widgetNavRequest = requestedNav,
+                            onWidgetNavConsumed = { requestedNav = null },
+                            requestedImportUri = requestedImportUri,
+                            onImportConsumed = { requestedImportUri = null },
+                        )
+                    }
+                    // A persistent corner marker so a debug build is never
+                    // mistaken for the production app; compiled out of release.
+                    if (BuildConfig.DEBUG) DebugRibbon()
+                }
+                pendingCrashReport?.let { report ->
+                    CrashReportDialog(
+                        report = report,
+                        onSend = {
+                            submitCrashReport(this@MainActivity, report)
+                            CrashReporter.clearReport(this@MainActivity)
+                            pendingCrashReport = null
+                        },
+                        onDismiss = {
+                            // Keep the report (Settings can still reach it); just
+                            // stop it popping on every launch.
+                            CrashReporter.dismissPrompt(this@MainActivity)
+                            pendingCrashReport = null
+                        },
+                    )
+                }
+            }
+        }
+    }
+
+    override fun onResume() {
+        super.onResume()
+        // Reaching a running UI means startup succeeded; reset the loop trail.
+        CrashReporter.markHealthy(this)
+    }
+
+    override fun onNewIntent(intent: Intent) {
+        super.onNewIntent(intent)
+        intent.detailKeyOrNull()?.let { requestedDetailKey = it }
+        intent.navRequestOrNull()?.let { requestedNav = it }
+        intent.importUriOrNull()?.let { requestedImportUri = it }
+    }
+
+    /**
+     * The `.ics` Uri an external app asked us to open (file manager `ACTION_VIEW`)
+     * or share into us (`ACTION_SEND`). Restricted to content/file schemes so the
+     * app's own `calendula://` deep-links never match.
+     */
+    private fun Intent.importUriOrNull(): Uri? {
+        val uri = when (action) {
+            Intent.ACTION_VIEW -> data
+            Intent.ACTION_SEND -> IntentCompat.getParcelableExtra(this, Intent.EXTRA_STREAM, Uri::class.java)
+            else -> null
+        } ?: return null
+        // The calendar "view time" Uri (a date tap) is also ACTION_VIEW/content;
+        // it's a navigation, not a file to import, so [navRequestOrNull] owns it.
+        if (uri.host == CALENDAR_PROVIDER_HOST) return null
+        return uri.takeIf { it.scheme == "content" || it.scheme == "file" }
+    }
+
+    /**
+     * The date a launcher/clock date tap points at, parsed from the AOSP calendar
+     * "view time" intent: ACTION_VIEW on `content://com.android.calendar/time/
+     * <epochMillis>`. Null for any other intent. The matching manifest filter is
+     * what lets users pick Calendula from the system calendar chooser (issue #9).
+     */
+    private fun Intent.calendarTimeDateOrNull(): LocalDate? {
+        if (action != Intent.ACTION_VIEW) return null
+        val uri = data ?: return null
+        if (uri.host != CALENDAR_PROVIDER_HOST) return null
+        val segments = uri.pathSegments
+        if (segments.firstOrNull() != "time") return null
+        val millis = segments.getOrNull(1)?.toLongOrNull() ?: return null
+        return Instant.fromEpochMilliseconds(millis)
+            .toLocalDateTime(TimeZone.currentSystemDefault()).date
+    }
+
+    private fun Intent.navRequestOrNull(): WidgetNavRequest? {
+        // An external date tap (launcher/clock) has no widget source, so it opens
+        // the day view rooted over the default home view (OpenDate source = null).
+        calendarTimeDateOrNull()?.let { return WidgetNavRequest.OpenDate(it.toString(), source = null) }
+        // A widget header tap: open a top-level view with no date drill-in. The
+        // empty string carried by [openViewIntent] means "the default home view".
+        if (hasExtra(EXTRA_OPEN_VIEW)) {
+            val name = getStringExtra(EXTRA_OPEN_VIEW).orEmpty()
+            return WidgetNavRequest.OpenView(CalendarView.entries.firstOrNull { it.name == name })
+        }
+        val source = sourceViewOrNull()
+        val eventId = getLongExtra(EXTRA_EVENT_ID, -1L)
+        return when {
+            // Launcher long-press "New event" shortcut. Static shortcut intents
+            // can't carry typed extras, so the action alone signals create-on-today.
+            action == ACTION_NEW_EVENT -> WidgetNavRequest.Create(null)
+            getBooleanExtra(EXTRA_CREATE, false) ->
+                WidgetNavRequest.Create(getStringExtra(EXTRA_DATE_ISO))
+            // A widget event tap carries both the occurrence and its source view;
+            // reminders (no source) fall through to [detailKeyOrNull] instead.
+            source != null && eventId != -1L -> WidgetNavRequest.OpenEvent(
+                eventId = eventId,
+                beginMillis = getLongExtra(EXTRA_BEGIN_MILLIS, 0L),
+                endMillis = getLongExtra(EXTRA_END_MILLIS, 0L),
+                source = source,
+            )
+            source != null && getStringExtra(EXTRA_DATE_ISO) != null ->
+                WidgetNavRequest.OpenDate(getStringExtra(EXTRA_DATE_ISO)!!, source)
+            else -> null
+        }
+    }
+
+    /** The view the launching widget represents, if any (see [EXTRA_SOURCE_VIEW]). */
+    private fun Intent.sourceViewOrNull(): CalendarView? =
+        getStringExtra(EXTRA_SOURCE_VIEW)
+            ?.let { name -> CalendarView.entries.firstOrNull { it.name == name } }
+
+    private fun Intent.detailKeyOrNull(): LongArray? {
+        // A widget event tap (source present) is routed through [navRequestOrNull]
+        // so it can also set the base view; only sourceless reminder taps land here.
+        if (sourceViewOrNull() != null) return null
+        val eventId = getLongExtra(EXTRA_EVENT_ID, -1L)
+        if (eventId == -1L) return null
+        return longArrayOf(
+            eventId,
+            getLongExtra(EXTRA_BEGIN_MILLIS, 0L),
+            getLongExtra(EXTRA_END_MILLIS, 0L),
+        )
+    }
+
+    companion object {
+        // The calendar provider's authority/host. A date tap arrives as
+        // ACTION_VIEW on content://com.android.calendar/time/<epochMillis>.
+        private const val CALENDAR_PROVIDER_HOST = "com.android.calendar"
+
+        private const val EXTRA_EVENT_ID = "de.jeanlucmakiola.calendula.extra.EVENT_ID"
+        private const val EXTRA_BEGIN_MILLIS = "de.jeanlucmakiola.calendula.extra.BEGIN"
+        private const val EXTRA_END_MILLIS = "de.jeanlucmakiola.calendula.extra.END"
+        private const val EXTRA_DATE_ISO = "de.jeanlucmakiola.calendula.extra.DATE_ISO"
+        private const val EXTRA_CREATE = "de.jeanlucmakiola.calendula.extra.CREATE"
+
+        // A widget header tap asking to open a top-level view (no date drill-in).
+        // Its value is the target [CalendarView] name, or "" for the default view.
+        private const val EXTRA_OPEN_VIEW = "de.jeanlucmakiola.calendula.extra.OPEN_VIEW"
+
+        // The [CalendarView] (by name) of the widget a launch came from. Roots the
+        // in-app back stack in that view; absent for non-widget launches (reminders).
+        private const val EXTRA_SOURCE_VIEW = "de.jeanlucmakiola.calendula.extra.SOURCE_VIEW"
+
+        // Fired by the launcher long-press "New event" shortcut (res/xml/
+        // shortcuts.xml hardcodes this string — keep the two in sync).
+        const val ACTION_NEW_EVENT = "de.jeanlucmakiola.calendula.action.NEW_EVENT"
+
+        /**
+         * Intent opening the detail screen of one occurrence (reminder
+         * notifications). The synthetic data URI keys the intent so
+         * PendingIntents for different occurrences never collapse into one.
+         */
+        fun eventDetailIntent(
+            context: Context,
+            eventId: Long,
+            beginMillis: Long,
+            endMillis: Long,
+        ): Intent = Intent(context, MainActivity::class.java).apply {
+            data = "calendula://event/$eventId/$beginMillis".toUri()
+            putExtra(EXTRA_EVENT_ID, eventId)
+            putExtra(EXTRA_BEGIN_MILLIS, beginMillis)
+            putExtra(EXTRA_END_MILLIS, endMillis)
+            addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+        }
+
+        /**
+         * Open the day view anchored on [date], drilled in over the launching
+         * widget's [source] view (home-screen widgets). Backing out of the day
+         * returns to [source], then to the default home view.
+         */
+        fun openDateIntent(context: Context, date: LocalDate, source: CalendarView): Intent =
+            Intent(context, MainActivity::class.java).apply {
+                data = "calendula://date/$date".toUri()
+                putExtra(EXTRA_DATE_ISO, date.toString())
+                putExtra(EXTRA_SOURCE_VIEW, source.name)
+                addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+            }
+
+        /**
+         * Open one occurrence's detail from a widget event tap, rooting the back
+         * stack in the widget's [source] view. Same occurrence-key shape as
+         * [eventDetailIntent]; the [source] extra is what distinguishes a widget
+         * tap (sets the base view) from a reminder tap (leaves it untouched).
+         */
+        fun openEventIntent(
+            context: Context,
+            eventId: Long,
+            beginMillis: Long,
+            endMillis: Long,
+            source: CalendarView,
+        ): Intent = eventDetailIntent(context, eventId, beginMillis, endMillis).apply {
+            putExtra(EXTRA_SOURCE_VIEW, source.name)
+        }
+
+        /** Open the create-event form prefilled for [date] (home-screen widgets). */
+        fun openCreateIntent(context: Context, date: LocalDate): Intent =
+            Intent(context, MainActivity::class.java).apply {
+                data = "calendula://create/$date".toUri()
+                putExtra(EXTRA_CREATE, true)
+                putExtra(EXTRA_DATE_ISO, date.toString())
+                addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+            }
+
+        /**
+         * Open the app on a top-level [view] with no date drill-in — a widget
+         * header tap. A null [view] opens the user's default home view (the agenda
+         * widget's "Upcoming" title); a concrete view roots there over the default
+         * home (the month widget's month/year title → [CalendarView.Month]). The
+         * per-view data URI keeps distinct headers' PendingIntents from collapsing.
+         */
+        fun openViewIntent(context: Context, view: CalendarView?): Intent =
+            Intent(context, MainActivity::class.java).apply {
+                data = "calendula://view/${view?.name ?: "default"}".toUri()
+                putExtra(EXTRA_OPEN_VIEW, view?.name ?: "")
+                addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
             }
     }
 }

app/src/main/java/de/jeanlucmakiola/calendula/data/backup/AutoBackup.kt

@@ -0,0 +1,176 @@
+package de.jeanlucmakiola.calendula.data.backup
+
+import android.Manifest
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.app.PendingIntent
+import android.content.Context
+import android.content.pm.PackageManager
+import android.os.Build
+import android.util.Log
+import androidx.core.app.NotificationCompat
+import androidx.core.app.NotificationManagerCompat
+import androidx.core.content.ContextCompat
+import androidx.core.net.toUri
+import androidx.work.CoroutineWorker
+import androidx.work.ExistingPeriodicWorkPolicy
+import androidx.work.ExistingWorkPolicy
+import androidx.work.OneTimeWorkRequestBuilder
+import androidx.work.PeriodicWorkRequestBuilder
+import androidx.work.WorkManager
+import androidx.work.WorkerParameters
+import dagger.hilt.EntryPoint
+import dagger.hilt.InstallIn
+import dagger.hilt.android.EntryPointAccessors
+import dagger.hilt.components.SingletonComponent
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
+import de.jeanlucmakiola.calendula.data.ics.IcsExporter
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import de.jeanlucmakiola.calendula.domain.ics.IcsWriter
+import kotlinx.coroutines.flow.first
+import java.util.concurrent.TimeUnit
+import kotlin.time.Clock
+
+/**
+ * Schedules and runs the automatic periodic `.ics` backup of local calendars
+ * (issue #8). One-way export only — it mirrors the manual "Back up" into a
+ * user-chosen folder on an interval; it is not a sync. Stays INTERNET-free:
+ * everything is local provider reads + a local file write.
+ */
+object BackupScheduler {
+
+    private const val WORK_NAME = "auto-backup"
+    private const val WORK_NAME_NOW = "auto-backup-now"
+
+    /**
+     * Reconcile the scheduled work with the current settings: enqueue a unique
+     * periodic request when backup is on and a folder is set, otherwise cancel
+     * it. WorkManager persists the request across reboots on its own.
+     *
+     * The first run is delayed by one interval so it never overlaps an immediate
+     * [runNow] (two simultaneous writes would race and leave a "(1)" duplicate).
+     */
+    fun apply(context: Context, enabled: Boolean, intervalMinutes: Long, hasFolder: Boolean) {
+        val workManager = WorkManager.getInstance(context)
+        if (!enabled || !hasFolder) {
+            workManager.cancelUniqueWork(WORK_NAME)
+            // Also cancel any pending immediate run — otherwise a failing run-now
+            // keeps retrying after the user has turned backup off.
+            workManager.cancelUniqueWork(WORK_NAME_NOW)
+            return
+        }
+        // WorkManager's own floor is 15 min; the UI floors the user choice at 30.
+        val interval = intervalMinutes.coerceAtLeast(15L)
+        val request = PeriodicWorkRequestBuilder<BackupWorker>(interval, TimeUnit.MINUTES)
+            .setInitialDelay(interval, TimeUnit.MINUTES)
+            .build()
+        workManager.enqueueUniquePeriodicWork(
+            WORK_NAME,
+            ExistingPeriodicWorkPolicy.UPDATE,
+            request,
+        )
+    }
+
+    /**
+     * Run one export immediately (e.g. right after enabling or changing the
+     * folder) for instant feedback. Unique + REPLACE so rapid taps coalesce into
+     * a single run rather than racing each other.
+     */
+    fun runNow(context: Context) {
+        WorkManager.getInstance(context).enqueueUniqueWork(
+            WORK_NAME_NOW,
+            ExistingWorkPolicy.REPLACE,
+            OneTimeWorkRequestBuilder<BackupWorker>().build(),
+        )
+    }
+}
+
+/**
+ * Exports the local calendars to `calendula-backup.ics` in the configured folder,
+ * overwriting the previous file. Pulls its collaborators through a Hilt
+ * [EntryPoint] so it works under WorkManager's default (no-arg) worker factory —
+ * no custom factory / Application wiring needed. Records the outcome for the
+ * settings status line, and notifies after repeated failures.
+ */
+class BackupWorker(
+    appContext: Context,
+    params: WorkerParameters,
+) : CoroutineWorker(appContext, params) {
+
+    @EntryPoint
+    @InstallIn(SingletonComponent::class)
+    interface Deps {
+        fun settingsPrefs(): SettingsPrefs
+        fun repository(): CalendarRepository
+        fun exporter(): IcsExporter
+    }
+
+    override suspend fun doWork(): Result {
+        val deps = EntryPointAccessors.fromApplication(applicationContext, Deps::class.java)
+        val prefs = deps.settingsPrefs()
+        // Respect the toggle even for already-queued work: if backup was turned
+        // off, no-op (and don't retry) so a lingering run can't revive itself.
+        if (!prefs.autoBackupEnabled.first()) return Result.success()
+        val folder = prefs.autoBackupFolderUri.first()
+            ?: return Result.failure() // nothing to write to — leave scheduling to settings
+        val now = System.currentTimeMillis()
+        return try {
+            val events = deps.repository().exportEvents()
+            val content = IcsWriter().writeCalendar(events, Clock.System.now())
+            deps.exporter().writeToFolder(folder.toUri(), BACKUP_FILE_NAME, content)
+            prefs.recordAutoBackupRun(success = true, atMillis = now)
+            Result.success()
+        } catch (e: Exception) {
+            prefs.recordAutoBackupRun(success = false, atMillis = now)
+            if (prefs.autoBackupStatus.first().consecutiveFailures >= FAILURE_NOTIFY_THRESHOLD) {
+                notifyFailure(applicationContext)
+            }
+            Log.w(TAG, "Automatic backup failed", e)
+            Result.retry()
+        }
+    }
+
+    private fun notifyFailure(context: Context) {
+        val canPost = Build.VERSION.SDK_INT < Build.VERSION_CODES.TIRAMISU ||
+            ContextCompat.checkSelfPermission(context, Manifest.permission.POST_NOTIFICATIONS) ==
+            PackageManager.PERMISSION_GRANTED
+        if (!canPost) return
+        val manager = NotificationManagerCompat.from(context)
+        manager.createNotificationChannel(
+            NotificationChannel(
+                CHANNEL_ID,
+                context.getString(R.string.backup_channel_name),
+                NotificationManager.IMPORTANCE_LOW,
+            ).apply { description = context.getString(R.string.backup_channel_description) },
+        )
+        val launch = context.packageManager.getLaunchIntentForPackage(context.packageName)
+        val tap = launch?.let {
+            PendingIntent.getActivity(
+                context, 0, it,
+                PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE,
+            )
+        }
+        val notification = NotificationCompat.Builder(context, CHANNEL_ID)
+            .setSmallIcon(R.drawable.ic_notification)
+            .setContentTitle(context.getString(R.string.backup_failed_title))
+            .setContentText(context.getString(R.string.backup_failed_text))
+            .setCategory(NotificationCompat.CATEGORY_ERROR)
+            .setAutoCancel(true)
+            .apply { tap?.let(::setContentIntent) }
+            .build()
+        try {
+            manager.notify(NOTIFICATION_ID, notification)
+        } catch (e: SecurityException) {
+            Log.w(TAG, "Could not post backup-failure notification", e)
+        }
+    }
+
+    companion object {
+        const val BACKUP_FILE_NAME = "calendula-backup.ics"
+        private const val FAILURE_NOTIFY_THRESHOLD = 2
+        private const val CHANNEL_ID = "backup"
+        private const val NOTIFICATION_ID = 2
+        private const val TAG = "BackupWorker"
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/AllDayReminderEncoding.kt

@@ -0,0 +1,91 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import java.time.Instant
+import java.time.LocalDate
+import java.time.LocalTime
+import java.time.ZoneId
+import java.time.ZoneOffset
+import java.time.temporal.ChronoUnit
+
+/**
+ * Translates an all-day reminder between the **semantic** lead time the UI
+ * speaks (whole days before the event — "1 day before") and the **raw**
+ * `CalendarContract.Reminders.MINUTES` offset the provider stores.
+ *
+ * Calendula schedules no alarms itself: the provider fires a reminder at
+ * `DTSTART − MINUTES` (the Etar model). An all-day event's DTSTART is **UTC
+ * midnight** (see [EventWriteTimes]), so a raw `MINUTES = 1440` ("1 day") lands
+ * on UTC-midnight of the previous day — 02:00 local in CEST, not the morning.
+ *
+ * To fire at a chosen wall-clock time we encode that time *into* the offset:
+ * `MINUTES = UTC-midnight(startDate) − (localInstant of [timeOfDayMinutes] on the
+ * day [semanticMinutes] before)`. The single fixed offset can only be tuned for
+ * the event's own date, so a recurring all-day series or a post-creation
+ * timezone change drifts the fire time by the offset delta (±1h across DST) —
+ * an inherent limit of the provider model, shared by Etar.
+ */
+private const val MINUTES_PER_DAY = 1_440
+private const val MILLIS_PER_MINUTE = 60_000L
+
+/**
+ * Raw provider `MINUTES` for an all-day reminder set [semanticMinutes] before the
+ * event (a whole-day multiple; sub-day remainders are dropped), so it fires at
+ * [timeOfDayMinutes] (minutes from local midnight) in [zone]. The result may be
+ * **negative** — e.g. "at time of event" at 09:00 CEST encodes to −420, meaning
+ * the provider fires *after* DTSTART; this is valid and must not be clamped.
+ * A negative [semanticMinutes] is the "provider default" sentinel and passes
+ * through unchanged.
+ */
+internal fun toProviderAllDayMinutes(
+    semanticMinutes: Int,
+    startDate: LocalDate,
+    zone: ZoneId,
+    timeOfDayMinutes: Int,
+): Int {
+    if (semanticMinutes < 0) return semanticMinutes
+    val utcMidnight = startDate.atStartOfDay(ZoneOffset.UTC).toInstant().toEpochMilli()
+    val fire = startDate.minusDays((semanticMinutes / MINUTES_PER_DAY).toLong())
+        .atTime(LocalTime.of(timeOfDayMinutes / 60, timeOfDayMinutes % 60))
+        .atZone(zone).toInstant().toEpochMilli()
+    return ((utcMidnight - fire) / MILLIS_PER_MINUTE).toInt()
+}
+
+/**
+ * The next date on or after [today] carrying [month]/[day] — the date to sample
+ * a yearly all-day reminder's UTC offset at. A managed birthday's DTSTART is an
+ * ancient anchor (1972 for year-less dates), a year whose timezone rules
+ * (pre-DST offsets) differ from today's; sampling the offset there skews every
+ * modern occurrence by hours. Sampling at the upcoming occurrence makes the
+ * stored offset correct for it and its neighbours (only ±1h DST drift remains,
+ * the inherent limit). Feb-29 skips forward to the next leap year.
+ */
+internal fun nextYearlyOccurrence(month: Int, day: Int, today: LocalDate): LocalDate {
+    var year = today.year
+    // A Feb-29 date is valid only every ~4 years; 8 tries always reaches one.
+    repeat(8) {
+        val candidate = runCatching { LocalDate.of(year, month, day) }.getOrNull()
+        if (candidate != null && !candidate.isBefore(today)) return candidate
+        year++
+    }
+    // Unreachable for real month/day inputs; fall back to the raw anchor.
+    return LocalDate.of(today.year, month, day)
+}
+
+/**
+ * Recover the semantic whole-day lead time from a raw all-day reminder
+ * [rawMinutes]. Keys off the **local date** of the encoded fire instant, so it
+ * returns the right day count regardless of which [timeOfDayMinutes] wrote the
+ * row — including pre-feature rows (raw multiples of 1440, fired at UTC midnight)
+ * and rows written under a different timezone. A negative [rawMinutes] (fire
+ * after DTSTART) folds to day 0.
+ */
+internal fun fromProviderAllDayMinutes(
+    rawMinutes: Int,
+    startDate: LocalDate,
+    zone: ZoneId,
+): Int {
+    val utcMidnight = startDate.atStartOfDay(ZoneOffset.UTC).toInstant().toEpochMilli()
+    val fireLocalDate = Instant.ofEpochMilli(utcMidnight - rawMinutes * MILLIS_PER_MINUTE)
+        .atZone(zone).toLocalDate()
+    return ChronoUnit.DAYS.between(fireLocalDate, startDate).toInt() * MINUTES_PER_DAY
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/CalendarColorPalette.kt

@@ -0,0 +1,22 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+/**
+ * Google-Calendar-style palette; ARGB ints for a raw `CALENDAR_COLOR` /
+ * `EVENT_COLOR`. The named entries exist for callers that need one specific
+ * hue (the managed special-dates calendars), so they can't drift from the
+ * swatches offered in the colour picker.
+ */
+object CalendarColorPalette {
+    val Red = 0xFFD50000.toInt()
+    val Orange = 0xFFE67C00.toInt()
+    val Amber = 0xFFF6BF26.toInt()
+    val Green = 0xFF33B679.toInt()
+    val DarkGreen = 0xFF0B8043.toInt()
+    val Blue = 0xFF039BE5.toInt()
+    val Indigo = 0xFF3F51B5.toInt()
+    val Purple = 0xFF8E24AA.toInt()
+    val Graphite = 0xFF616161.toInt()
+
+    /** The full palette, in swatch-row order. */
+    val all: List<Int> = listOf(Red, Orange, Amber, Green, DarkGreen, Blue, Indigo, Purple, Graphite)
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/CalendarMapper.kt

@@ -1,13 +1,35 @@
 package de.jeanlucmakiola.calendula.data.calendar
 
+import android.provider.CalendarContract
 import de.jeanlucmakiola.calendula.domain.CalendarSource
 
-internal fun ColumnReader.toCalendarSource(): CalendarSource = CalendarSource(
+internal fun ColumnReader.toCalendarSource(): CalendarSource {
+    val accountType = getString(CalendarProjection.IDX_ACCOUNT_TYPE).orEmpty()
+    val isLocal = accountType == CalendarContract.ACCOUNT_TYPE_LOCAL
+    return CalendarSource(
         id = getLong(CalendarProjection.IDX_ID),
         displayName = getString(CalendarProjection.IDX_DISPLAY_NAME)
             ?: Fallbacks.UNNAMED_CALENDAR,
         accountName = getString(CalendarProjection.IDX_ACCOUNT_NAME).orEmpty(),
-    accountType = getString(CalendarProjection.IDX_ACCOUNT_TYPE).orEmpty(),
+        accountType = accountType,
         color = getInt(CalendarProjection.IDX_COLOR),
         isVisibleInSystem = getInt(CalendarProjection.IDX_VISIBLE) != 0,
-)
+        canModifyContents = getInt(CalendarProjection.IDX_ACCESS_LEVEL) >=
+            CalendarContract.Calendars.CAL_ACCESS_CONTRIBUTOR,
+        isLocal = isLocal,
+        // CAL_SYNC1 holds the sync token for synced rows, so only treat it as a
+        // user description on the local calendars the app owns.
+        description = if (isLocal) {
+            getString(CalendarProjection.IDX_DESCRIPTION)?.takeIf { it.isNotBlank() }
+        } else {
+            null
+        },
+        // A special-dates mirror calendar, recognised by its durable CAL_SYNC2
+        // marker (only meaningful on the local calendars the app owns). This is
+        // the source of truth for the editor lock — independent of any stored
+        // preference that a backup restore could have wiped.
+        isManaged = isLocal &&
+            getString(CalendarProjection.IDX_MANAGED_MARKER)
+                ?.startsWith(CalendarProjection.MANAGED_MARKER_PREFIX) == true,
+    )
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/CalendarRepository.kt

@@ -1,8 +1,13 @@
 package de.jeanlucmakiola.calendula.data.calendar
 
 import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventColorOption
 import de.jeanlucmakiola.calendula.domain.EventDetail
+import de.jeanlucmakiola.calendula.domain.EventForm
 import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.domain.ics.IcsEvent
+import de.jeanlucmakiola.calendula.domain.ics.IcsImportSummary
+import de.jeanlucmakiola.calendula.domain.ics.ParsedIcsEvent
 import kotlinx.coroutines.flow.Flow
 import kotlin.time.Instant
 
@@ -10,7 +15,81 @@ interface CalendarRepository {
     fun calendars(): Flow<List<CalendarSource>>
     fun instances(range: ClosedRange<Instant>): Flow<List<EventInstance>>
     suspend fun eventDetail(eventId: Long): EventDetail
+
+    /**
+     * Events whose title, description or location contains [query], with hidden
+     * calendars removed and newest first. Empty when [query] is blank. Searches
+     * the whole history/future (see [CalendarDataSource.searchEvents]).
+     */
+    suspend fun searchEvents(query: String): List<EventInstance>
+
+    /**
+     * The event-colour palette a calendar's account publishes; empty when it
+     * exposes none (see [CalendarDataSource.eventColorPalette]).
+     */
+    suspend fun eventColorPalette(calendarId: Long): List<EventColorOption>
+
+    /** Create a device-only (LOCAL) calendar the app owns; returns its id. */
+    suspend fun createLocalCalendar(displayName: String, color: Int, description: String?): Long
+
+    /** Update name, color and description of a local calendar the app owns. */
+    suspend fun updateCalendar(id: Long, displayName: String, color: Int, description: String?)
+
+    /** Permanently delete a local calendar the app owns, with all its events. */
+    suspend fun deleteCalendar(id: Long)
+
+    /**
+     * Every event of the writable local calendars, ready to serialise into a
+     * whole-calendar `.ics` backup (see [CalendarDataSource.exportableEvents]).
+     */
+    suspend fun exportEvents(): List<IcsEvent>
+
+    /**
+     * Bulk-import parsed `.ics` [events] into [targetCalendarId]. Events whose
+     * UID already exists in the target are skipped (idempotent restore); the
+     * rest are inserted. See [CalendarDataSource.insertImportedEvent].
+     */
+    suspend fun importEvents(targetCalendarId: Long, events: List<ParsedIcsEvent>): IcsImportSummary
+
+    /** Create a new event from a validated form; returns the new `Events._ID`. */
+    suspend fun createEvent(form: EventForm): Long
+
+    /**
+     * Update an event (recurring: the whole series) from a validated form.
+     * [original] is the prefilled form, used to write only what changed.
+     */
+    suspend fun updateEvent(eventId: Long, original: EventForm, updated: EventForm)
+
+    /**
+     * Change a single occurrence of a recurring event (exception row with the
+     * form's values); returns the exception's `Events._ID`.
+     */
+    suspend fun updateOccurrence(eventId: Long, beginMillis: Long, form: EventForm): Long
+
+    /**
+     * Change a recurring event from [beginMillis] onwards (series split);
+     * returns the new event's `Events._ID`.
+     */
+    suspend fun updateEventFromOccurrence(
+        eventId: Long,
+        beginMillis: Long,
+        original: EventForm,
+        updated: EventForm,
+    ): Long
+
+    /** Delete the whole event (for recurring events: the entire series). */
+    suspend fun deleteEvent(eventId: Long)
+
+    /** Cancel a single occurrence of a recurring event at its `Instances.BEGIN` time. */
+    suspend fun deleteOccurrence(eventId: Long, beginMillis: Long)
+
+    /** Delete a recurring event from the occurrence at [beginMillis] onwards. */
+    suspend fun deleteEventFromOccurrence(eventId: Long, beginMillis: Long)
 }
 
 class NoSuchEventException(eventId: Long) :
     NoSuchElementException("No event with id=$eventId")
+
+/** A ContentResolver write affected no rows or returned no URI. */
+class WriteFailedException(operation: String) :
+    RuntimeException("Calendar write failed: $operation")

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/CalendarRepositoryImpl.kt

@@ -1,12 +1,21 @@
 package de.jeanlucmakiola.calendula.data.calendar
 
 import de.jeanlucmakiola.calendula.data.di.IoDispatcher
+import de.jeanlucmakiola.calendula.data.prefs.CalendarPrefs
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
 import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventColorOption
 import de.jeanlucmakiola.calendula.domain.EventDetail
+import de.jeanlucmakiola.calendula.domain.EventForm
 import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.domain.ics.IcsImportSummary
+import de.jeanlucmakiola.calendula.domain.ics.ParsedIcsEvent
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.distinctUntilChanged
+import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.onStart
@@ -23,9 +32,15 @@ import javax.inject.Singleton
 @Singleton
 class CalendarRepositoryImpl @Inject constructor(
     private val dataSource: CalendarDataSource,
+    private val prefs: CalendarPrefs,
+    private val settingsPrefs: SettingsPrefs,
     @IoDispatcher private val io: CoroutineDispatcher,
 ) : CalendarRepository {
 
+    /** The configured wall-clock fire time for all-day reminders, read per write. */
+    private suspend fun allDayReminderTimeMinutes(): Int =
+        settingsPrefs.allDayReminderTimeMinutes.first()
+
     private val ticks = MutableSharedFlow<Unit>(
         replay = 0,
         extraBufferCapacity = 1,
@@ -41,7 +56,14 @@ class CalendarRepositoryImpl @Inject constructor(
             .reQuery { dataSource.calendars() }
             .flowOn(io)
 
+    // Instances are filtered by the app-side hidden ∪ disabled calendar sets
+    // (M3): an event is dropped whenever the user has hidden *or* disabled its
+    // calendar. Re-runs when the provider ticks *or* either set changes —
+    // toggling a calendar in the filter sheet or the calendar manager updates
+    // every view immediately. [calendars] stays unfiltered so those screens can
+    // list and re-enable hidden/disabled calendars.
     override fun instances(range: ClosedRange<Instant>): Flow<List<EventInstance>> =
+        combine(
             ticks
                 .onStart { emit(Unit) }
                 .reQuery {
@@ -49,12 +71,119 @@ class CalendarRepositoryImpl @Inject constructor(
                         beginMillis = range.start.toEpochMillis(),
                         endMillis = range.endInclusive.toEpochMillis(),
                     )
+                },
+            prefs.hiddenCalendarIds,
+            prefs.disabledCalendarIds,
+        ) { instances, hidden, disabled ->
+            val excluded = hidden + disabled
+            if (excluded.isEmpty()) instances
+            else instances.filterNot { it.calendarId in excluded }
         }
+            // hidden and disabled both derive from one DataStore, so toggling
+            // either makes both re-emit and combine briefly surfaces the same
+            // list twice — collapse the duplicate so views don't re-render for it.
+            .distinctUntilChanged()
             .flowOn(io)
 
     override suspend fun eventDetail(eventId: Long): EventDetail = withContext(io) {
         dataSource.eventDetail(eventId) ?: throw NoSuchEventException(eventId)
     }
+
+    override suspend fun searchEvents(query: String): List<EventInstance> = withContext(io) {
+        if (query.isBlank()) return@withContext emptyList()
+        val excluded = prefs.hiddenCalendarIds.first() + prefs.disabledCalendarIds.first()
+        dataSource.searchEvents(query)
+            .let { if (excluded.isEmpty()) it else it.filterNot { e -> e.calendarId in excluded } }
+    }
+
+    override suspend fun eventColorPalette(calendarId: Long): List<EventColorOption> =
+        withContext(io) { dataSource.eventColorPalette(calendarId) }
+
+    override suspend fun createLocalCalendar(
+        displayName: String,
+        color: Int,
+        description: String?,
+    ): Long = withContext(io) {
+        dataSource.createLocalCalendar(displayName, color, description)
+    }
+
+    override suspend fun updateCalendar(
+        id: Long,
+        displayName: String,
+        color: Int,
+        description: String?,
+    ) = withContext(io) { dataSource.updateCalendar(id, displayName, color, description) }
+
+    override suspend fun deleteCalendar(id: Long) =
+        withContext(io) { dataSource.deleteCalendar(id) }
+
+    override suspend fun exportEvents() = withContext(io) { dataSource.exportableEvents() }
+
+    override suspend fun importEvents(
+        targetCalendarId: Long,
+        events: List<ParsedIcsEvent>,
+    ): IcsImportSummary = withContext(io) {
+        val existing = dataSource.existingUids(targetCalendarId)
+        var imported = 0
+        var skipped = 0
+        for (event in events) {
+            // A known UID means the event is already in this calendar — skip,
+            // keeping a restore idempotent (no overwrite this pass).
+            if (event.uid != null && event.uid in existing) {
+                skipped++
+            } else {
+                dataSource.insertImportedEvent(event, targetCalendarId)
+                imported++
+            }
+        }
+        IcsImportSummary(imported = imported, skippedDuplicate = skipped)
+    }
+
+    override suspend fun createEvent(form: EventForm): Long = withContext(io) {
+        dataSource.insertEvent(form, allDayReminderTimeMinutes())
+    }
+
+    override suspend fun updateEvent(
+        eventId: Long,
+        original: EventForm,
+        updated: EventForm,
+    ) = withContext(io) {
+        dataSource.updateEvent(eventId, original, updated, allDayReminderTimeMinutes())
+    }
+
+    override suspend fun deleteEvent(eventId: Long) = withContext(io) {
+        dataSource.deleteEvent(eventId)
+    }
+
+    override suspend fun updateOccurrence(
+        eventId: Long,
+        beginMillis: Long,
+        form: EventForm,
+    ): Long = withContext(io) {
+        dataSource.updateOccurrence(eventId, beginMillis, form, allDayReminderTimeMinutes())
+    }
+
+    override suspend fun updateEventFromOccurrence(
+        eventId: Long,
+        beginMillis: Long,
+        original: EventForm,
+        updated: EventForm,
+    ): Long = withContext(io) {
+        dataSource.updateEventFromOccurrence(
+            eventId, beginMillis, original, updated, allDayReminderTimeMinutes(),
+        )
+    }
+
+    override suspend fun deleteOccurrence(eventId: Long, beginMillis: Long) = withContext(io) {
+        dataSource.deleteOccurrence(eventId, beginMillis)
+    }
+
+    override suspend fun deleteEventFromOccurrence(
+        eventId: Long,
+        beginMillis: Long,
+    ) = withContext(io) {
+        dataSource.deleteEventFromOccurrence(eventId, beginMillis)
+    }
 }
 
 private fun <T> Flow<Unit>.reQuery(block: suspend () -> T): Flow<T> = flow {

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/EventDetailMapper.kt

@@ -2,36 +2,69 @@ package de.jeanlucmakiola.calendula.data.calendar
 
 import android.provider.CalendarContract
 import android.util.Log
+import de.jeanlucmakiola.calendula.domain.AccessLevel
 import de.jeanlucmakiola.calendula.domain.Attendee
+import de.jeanlucmakiola.calendula.domain.AttendeeRelationship
 import de.jeanlucmakiola.calendula.domain.AttendeeStatus
+import de.jeanlucmakiola.calendula.domain.AttendeeType
+import de.jeanlucmakiola.calendula.domain.Availability
 import de.jeanlucmakiola.calendula.domain.EventDetail
 import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.domain.EventStatus
+import de.jeanlucmakiola.calendula.domain.Reminder
+import de.jeanlucmakiola.calendula.domain.ReminderMethod
+import java.time.Instant
+import java.time.ZoneId
+import java.time.ZoneOffset
 
 private const val TAG = "EventDetailMapper"
 
-internal fun ColumnReader.toEventDetailCore(attendees: List<Attendee>): EventDetail? {
+internal fun ColumnReader.toEventDetailCore(
+    attendees: List<Attendee>,
+    reminders: List<Reminder>,
+): EventDetail? {
+    // DTSTART is epoch millis in UTC, so a series anchored before 1970 (common
+    // for yearly birthdays/anniversaries synced over CalDAV) is legitimately
+    // negative — only an *absent* DTSTART marks a malformed row worth dropping.
+    // Dropping negatives made every occurrence of such a series un-openable
+    // (the detail loads the ancient series-master DTSTART), see issue #34.
+    if (isNull(EventDetailProjection.IDX_DTSTART)) {
+        Log.w(TAG, "Dropping event with missing dtstart")
+        return null
+    }
     val begin = getLong(EventDetailProjection.IDX_DTSTART)
-    val end = getLong(EventDetailProjection.IDX_DTEND)
 
-    if (begin < 0L) {
-        Log.w(TAG, "Dropping event with negative dtstart=$begin")
-        return null
-    }
-    if (end < begin) {
-        Log.w(TAG, "Dropping event with dtend=$end < dtstart=$begin")
-        return null
+    // Recurring events store DURATION instead of DTEND, so the series row's
+    // DTEND is null. Keep the event (end == begin); callers that opened a
+    // specific occurrence supply the real per-occurrence times from
+    // CalendarContract.Instances. A present-but-backwards DTEND is malformed,
+    // but dropping the row would make the event un-openable — the same trap as
+    // the pre-1970 DTSTART bug above (issue #34): it would surface as the
+    // generic error screen with no way to open the event and fix it. Clamp to a
+    // zero-length event instead (matching SearchMapper's coerceAtLeast).
+    val end = if (isNull(EventDetailProjection.IDX_DTEND)) {
+        begin
+    } else {
+        getLong(EventDetailProjection.IDX_DTEND).coerceAtLeast(begin)
     }
 
-    val rawTitle = getString(EventDetailProjection.IDX_TITLE)
-    val title = if (rawTitle.isNullOrEmpty()) Fallbacks.UNTITLED_EVENT else rawTitle
+    // Kept raw (no untitled fallback): the detail screen substitutes its own
+    // localized placeholder, and the edit form must prefill the true value.
+    val title = getString(EventDetailProjection.IDX_TITLE).orEmpty()
 
-    val color = if (isNull(EventDetailProjection.IDX_EVENT_COLOR)) {
-        getInt(EventDetailProjection.IDX_CALENDAR_COLOR)
+    // The event's own colour (null = inherits the calendar's) is kept apart
+    // from the resolved display colour: the edit form needs to tell the two
+    // cases apart, while the instance carries the calendar fallback for display.
+    val eventColor = if (isNull(EventDetailProjection.IDX_EVENT_COLOR)) {
+        null
     } else {
         getInt(EventDetailProjection.IDX_EVENT_COLOR)
     }
+    val eventColorKey = getString(EventDetailProjection.IDX_EVENT_COLOR_KEY)
+    val color = eventColor ?: getInt(EventDetailProjection.IDX_CALENDAR_COLOR)
 
     val eventId = getLong(EventDetailProjection.IDX_EVENT_ID)
+    val isAllDay = getInt(EventDetailProjection.IDX_ALL_DAY) != 0
     val instance = EventInstance(
         instanceId = eventId,
         eventId = eventId,
@@ -39,17 +72,47 @@ internal fun ColumnReader.toEventDetailCore(attendees: List<Attendee>): EventDet
         title = title,
         start = begin.toKotlinInstantFromEpochMillis(),
         end = end.toKotlinInstantFromEpochMillis(),
-        isAllDay = getInt(EventDetailProjection.IDX_ALL_DAY) != 0,
+        isAllDay = isAllDay,
         color = color,
         location = getString(EventDetailProjection.IDX_LOCATION),
     )
 
+    // All-day reminders are stored as a wall-clock-shifted offset (see
+    // AllDayReminderEncoding); decode back to the whole-day lead time the form
+    // and detail screen speak. DTSTART is UTC midnight for all-day events, so the
+    // event's date is its UTC date.
+    val displayReminders = if (isAllDay) {
+        val startDate = Instant.ofEpochMilli(begin).atZone(ZoneOffset.UTC).toLocalDate()
+        val zone = ZoneId.systemDefault()
+        reminders.map { it.copy(minutes = fromProviderAllDayMinutes(it.minutes, startDate, zone)) }
+    } else {
+        reminders
+    }
+
+    // STATUS shares its 0 value with STATUS_TENTATIVE, so a missing column must
+    // be distinguished from a present 0 — an absent status means "just confirmed".
+    val status = if (isNull(EventDetailProjection.IDX_STATUS)) {
+        EventStatus.Confirmed
+    } else {
+        mapEventStatus(getInt(EventDetailProjection.IDX_STATUS))
+    }
+
     return EventDetail(
         instance = instance,
         description = getString(EventDetailProjection.IDX_DESCRIPTION),
         organizer = getString(EventDetailProjection.IDX_ORGANIZER),
         attendees = attendees,
         rrule = getString(EventDetailProjection.IDX_RRULE),
+        reminders = displayReminders,
+        status = status,
+        // BUSY and DEFAULT are both 0, so a null column folds into the same
+        // default these mappers already return — no isNull guard needed.
+        availability = mapAvailability(getInt(EventDetailProjection.IDX_AVAILABILITY)),
+        accessLevel = mapAccessLevel(getInt(EventDetailProjection.IDX_ACCESS_LEVEL)),
+        eventTimezone = getString(EventDetailProjection.IDX_EVENT_TIMEZONE),
+        selfStatus = mapAttendeeStatus(getInt(EventDetailProjection.IDX_SELF_ATTENDEE_STATUS)),
+        eventColor = eventColor,
+        eventColorKey = eventColorKey,
     )
 }
 
@@ -57,6 +120,13 @@ internal fun ColumnReader.toAttendee(): Attendee = Attendee(
     name = getString(AttendeeProjection.IDX_NAME).orEmpty(),
     email = getString(AttendeeProjection.IDX_EMAIL),
     status = mapAttendeeStatus(getInt(AttendeeProjection.IDX_STATUS)),
+    relationship = mapAttendeeRelationship(getInt(AttendeeProjection.IDX_RELATIONSHIP)),
+    type = mapAttendeeType(getInt(AttendeeProjection.IDX_TYPE)),
+)
+
+internal fun ColumnReader.toReminder(): Reminder = Reminder(
+    minutes = getInt(ReminderProjection.IDX_MINUTES),
+    method = mapReminderMethod(getInt(ReminderProjection.IDX_METHOD)),
 )
 
 internal fun mapAttendeeStatus(raw: Int): AttendeeStatus = when (raw) {
@@ -66,3 +136,46 @@ internal fun mapAttendeeStatus(raw: Int): AttendeeStatus = when (raw) {
     CalendarContract.Attendees.ATTENDEE_STATUS_INVITED -> AttendeeStatus.NeedsAction
     else -> AttendeeStatus.Unknown
 }
+
+internal fun mapAttendeeRelationship(raw: Int): AttendeeRelationship = when (raw) {
+    CalendarContract.Attendees.RELATIONSHIP_ORGANIZER -> AttendeeRelationship.Organizer
+    CalendarContract.Attendees.RELATIONSHIP_PERFORMER -> AttendeeRelationship.Performer
+    CalendarContract.Attendees.RELATIONSHIP_SPEAKER -> AttendeeRelationship.Speaker
+    CalendarContract.Attendees.RELATIONSHIP_ATTENDEE -> AttendeeRelationship.Attendee
+    else -> AttendeeRelationship.None
+}
+
+internal fun mapAttendeeType(raw: Int): AttendeeType = when (raw) {
+    CalendarContract.Attendees.TYPE_REQUIRED -> AttendeeType.Required
+    CalendarContract.Attendees.TYPE_OPTIONAL -> AttendeeType.Optional
+    CalendarContract.Attendees.TYPE_RESOURCE -> AttendeeType.Resource
+    else -> AttendeeType.None
+}
+
+internal fun mapEventStatus(raw: Int): EventStatus = when (raw) {
+    CalendarContract.Events.STATUS_CONFIRMED -> EventStatus.Confirmed
+    CalendarContract.Events.STATUS_TENTATIVE -> EventStatus.Tentative
+    CalendarContract.Events.STATUS_CANCELED -> EventStatus.Cancelled
+    else -> EventStatus.Confirmed
+}
+
+internal fun mapAvailability(raw: Int): Availability = when (raw) {
+    CalendarContract.Events.AVAILABILITY_FREE -> Availability.Free
+    CalendarContract.Events.AVAILABILITY_TENTATIVE -> Availability.Tentative
+    else -> Availability.Busy
+}
+
+internal fun mapAccessLevel(raw: Int): AccessLevel = when (raw) {
+    CalendarContract.Events.ACCESS_CONFIDENTIAL -> AccessLevel.Confidential
+    CalendarContract.Events.ACCESS_PRIVATE -> AccessLevel.Private
+    CalendarContract.Events.ACCESS_PUBLIC -> AccessLevel.Public
+    else -> AccessLevel.Default
+}
+
+internal fun mapReminderMethod(raw: Int): ReminderMethod = when (raw) {
+    CalendarContract.Reminders.METHOD_EMAIL -> ReminderMethod.Email
+    CalendarContract.Reminders.METHOD_SMS -> ReminderMethod.Sms
+    CalendarContract.Reminders.METHOD_ALARM -> ReminderMethod.Alarm
+    CalendarContract.Reminders.METHOD_ALERT -> ReminderMethod.Alert
+    else -> ReminderMethod.Default
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/EventWriteMapper.kt

@@ -0,0 +1,231 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import android.provider.CalendarContract
+import de.jeanlucmakiola.calendula.domain.AccessLevel
+import de.jeanlucmakiola.calendula.domain.Availability
+import de.jeanlucmakiola.calendula.domain.EventForm
+import kotlinx.datetime.toJavaLocalDate
+import kotlinx.datetime.toJavaLocalDateTime
+import java.time.Instant
+import java.time.ZoneId
+import java.time.ZoneOffset
+
+/** Provider-ready DTSTART / DTEND / EVENT_TIMEZONE for an event write. */
+internal data class EventWriteTimes(
+    val dtStartMillis: Long,
+    val dtEndMillis: Long,
+    val timezone: String,
+)
+
+/**
+ * All-day events live at UTC midnights with an exclusive DTEND (the
+ * CalendarContract convention — a one-day event ends at the next midnight);
+ * timed events resolve their wall-clock values in [zone].
+ */
+internal fun EventForm.toWriteTimes(zone: ZoneId): EventWriteTimes = if (isAllDay) {
+    EventWriteTimes(
+        dtStartMillis = start.date.toJavaLocalDate()
+            .atStartOfDay(ZoneOffset.UTC).toInstant().toEpochMilli(),
+        dtEndMillis = end.date.toJavaLocalDate().plusDays(1)
+            .atStartOfDay(ZoneOffset.UTC).toInstant().toEpochMilli(),
+        timezone = "UTC",
+    )
+} else {
+    EventWriteTimes(
+        dtStartMillis = start.toJavaLocalDateTime().atZone(zone).toInstant().toEpochMilli(),
+        dtEndMillis = end.toJavaLocalDateTime().atZone(zone).toInstant().toEpochMilli(),
+        timezone = zone.id,
+    )
+}
+
+/**
+ * RFC 2445 duration for a recurring event's row (the provider requires
+ * DURATION instead of DTEND when an RRULE is set): whole days for all-day
+ * events, seconds otherwise.
+ */
+internal fun EventWriteTimes.toRfc2445Duration(isAllDay: Boolean): String = if (isAllDay) {
+    "P${(dtEndMillis - dtStartMillis) / MILLIS_PER_DAY}D"
+} else {
+    "P${(dtEndMillis - dtStartMillis) / 1_000L}S"
+}
+
+/**
+ * Column values for a brand-new Events row: identity, times (the provider's
+ * invariant — recurring rows carry RRULE+DURATION and no DTEND, one-off rows
+ * carry DTEND), availability/access level and trimmed optional text. Shared by
+ * the user-event and managed-event insert paths, which differ only in the
+ * [uid] they stamp; colour and attendees are user-event concerns the caller
+ * layers on top.
+ */
+internal fun buildEventInsertValues(
+    form: EventForm,
+    uid: String,
+    times: EventWriteTimes,
+): Map<String, Any?> = buildMap {
+    put(
+        CalendarContract.Events.CALENDAR_ID,
+        requireNotNull(form.calendarId) { "EventForm.calendarId is required" },
+    )
+    put(CalendarContract.Events.UID_2445, uid)
+    put(CalendarContract.Events.TITLE, form.title.trim())
+    put(CalendarContract.Events.ALL_DAY, if (form.isAllDay) 1 else 0)
+    put(CalendarContract.Events.DTSTART, times.dtStartMillis)
+    if (form.rrule == null) {
+        put(CalendarContract.Events.DTEND, times.dtEndMillis)
+    } else {
+        put(CalendarContract.Events.RRULE, form.rrule)
+        put(CalendarContract.Events.DURATION, times.toRfc2445Duration(form.isAllDay))
+    }
+    put(CalendarContract.Events.EVENT_TIMEZONE, times.timezone)
+    put(CalendarContract.Events.AVAILABILITY, form.availability.toProviderValue())
+    put(CalendarContract.Events.ACCESS_LEVEL, form.accessLevel.toProviderValue())
+    form.location.trim().takeIf { it.isNotEmpty() }
+        ?.let { put(CalendarContract.Events.EVENT_LOCATION, it) }
+    form.description.trim().takeIf { it.isNotEmpty() }
+        ?.let { put(CalendarContract.Events.DESCRIPTION, it) }
+}
+
+/**
+ * Dirty-checked column values for updating an existing Events row: only what
+ * the user actually changed is written, so untouched fields can't stomp
+ * concurrent external edits. Keys are `CalendarContract.Events` columns; a
+ * null value means "set the column to NULL". An empty map means nothing on
+ * the row changed.
+ *
+ * Time fields travel together (the provider validates them as a unit):
+ * - unchanged times, all-day flag and rrule → no time columns at all;
+ * - non-recurring result → DTSTART/DTEND, DURATION and RRULE cleared;
+ * - recurring result → the *series* DTSTART moves by the same delta the user
+ *   applied to the displayed occurrence ([seriesDtStartMillis] is the row's
+ *   current DTSTART), DURATION replaces DTEND, RRULE is written. This keeps
+ *   past occurrences intact when someone edits a later occurrence's time.
+ */
+internal fun buildEventUpdateValues(
+    original: EventForm,
+    updated: EventForm,
+    seriesDtStartMillis: Long,
+    zone: ZoneId,
+): Map<String, Any?> = buildMap {
+    if (updated.title.trim() != original.title.trim()) {
+        put(CalendarContract.Events.TITLE, updated.title.trim())
+    }
+    if (updated.location.trim() != original.location.trim()) {
+        put(CalendarContract.Events.EVENT_LOCATION, updated.location.trim().ifEmpty { null })
+    }
+    if (updated.description.trim() != original.description.trim()) {
+        put(CalendarContract.Events.DESCRIPTION, updated.description.trim().ifEmpty { null })
+    }
+    if (updated.availability != original.availability) {
+        put(CalendarContract.Events.AVAILABILITY, updated.availability.toProviderValue())
+    }
+    if (updated.accessLevel != original.accessLevel) {
+        put(CalendarContract.Events.ACCESS_LEVEL, updated.accessLevel.toProviderValue())
+    }
+    if (updated.colorKey != original.colorKey || updated.color != original.color) {
+        putAll(eventColorColumns(updated.colorKey, updated.color))
+    }
+
+    val timesChanged = updated.start != original.start ||
+        updated.end != original.end ||
+        updated.isAllDay != original.isAllDay ||
+        updated.rrule != original.rrule
+    if (!timesChanged) return@buildMap
+
+    val newTimes = updated.toWriteTimes(zone)
+    put(CalendarContract.Events.ALL_DAY, if (updated.isAllDay) 1 else 0)
+    put(CalendarContract.Events.EVENT_TIMEZONE, newTimes.timezone)
+    if (updated.rrule == null) {
+        put(CalendarContract.Events.DTSTART, newTimes.dtStartMillis)
+        put(CalendarContract.Events.DTEND, newTimes.dtEndMillis)
+        put(CalendarContract.Events.RRULE, null)
+        put(CalendarContract.Events.DURATION, null)
+    } else {
+        val startDelta = newTimes.dtStartMillis - original.toWriteTimes(zone).dtStartMillis
+        put(CalendarContract.Events.DTSTART, seriesDtStartMillis + startDelta)
+        put(CalendarContract.Events.DTEND, null)
+        put(CalendarContract.Events.RRULE, updated.rrule)
+        put(CalendarContract.Events.DURATION, newTimes.toRfc2445Duration(updated.isAllDay))
+    }
+}
+
+/**
+ * Column values for a modified-occurrence exception row ("edit only this
+ * event"): inserting them at `Events.CONTENT_EXCEPTION_URI/<id>` makes the
+ * provider clone the series row and apply these on top. Unlike the series
+ * update there is no dirty check — the exception is a fresh row, so every
+ * form-backed column is written (empty optionals as explicit NULLs, since the
+ * clone starts from the parent's values).
+ *
+ * The occurrence's length travels as DURATION, never DTEND: the provider
+ * rejects DTEND on an exception outright (`CalendarProvider2`:
+ * "Exceptions can't overwrite dtend") and derives the instance end from
+ * DTSTART + DURATION itself, clearing the inherited RRULE in the process. This
+ * matches how AOSP Calendar/Etar write exceptions; sending DTEND is what made
+ * "only this event" fail on-device (Codeberg #16).
+ */
+internal fun buildOccurrenceExceptionValues(
+    form: EventForm,
+    originalInstanceMillis: Long,
+    zone: ZoneId,
+): Map<String, Any?> = buildMap {
+    val times = form.toWriteTimes(zone)
+    put(CalendarContract.Events.ORIGINAL_INSTANCE_TIME, originalInstanceMillis)
+    put(CalendarContract.Events.TITLE, form.title.trim())
+    put(CalendarContract.Events.ALL_DAY, if (form.isAllDay) 1 else 0)
+    put(CalendarContract.Events.DTSTART, times.dtStartMillis)
+    put(CalendarContract.Events.DURATION, times.toRfc2445Duration(form.isAllDay))
+    put(CalendarContract.Events.EVENT_TIMEZONE, times.timezone)
+    put(CalendarContract.Events.AVAILABILITY, form.availability.toProviderValue())
+    put(CalendarContract.Events.ACCESS_LEVEL, form.accessLevel.toProviderValue())
+    put(CalendarContract.Events.EVENT_LOCATION, form.location.trim().ifEmpty { null })
+    put(CalendarContract.Events.DESCRIPTION, form.description.trim().ifEmpty { null })
+    putAll(eventColorColumns(form.colorKey, form.color))
+}
+
+/**
+ * The `EVENT_COLOR` / `EVENT_COLOR_KEY` columns for a colour selection. A
+ * [colorKey] writes the key alone (the provider derives `EVENT_COLOR` from the
+ * account's palette, so the colour round-trips through sync); a raw [color]
+ * writes `EVENT_COLOR` and clears any key; "no colour" clears both so the event
+ * falls back to its calendar's colour. The two are never written together —
+ * the provider rejects a raw colour on a calendar that publishes a palette,
+ * which is exactly why palette calendars only ever go through the key.
+ */
+internal fun eventColorColumns(colorKey: String?, color: Int?): Map<String, Any?> = when {
+    colorKey != null -> mapOf(CalendarContract.Events.EVENT_COLOR_KEY to colorKey)
+    color != null -> mapOf(
+        CalendarContract.Events.EVENT_COLOR_KEY to null,
+        CalendarContract.Events.EVENT_COLOR to color,
+    )
+    else -> mapOf(
+        CalendarContract.Events.EVENT_COLOR_KEY to null,
+        CalendarContract.Events.EVENT_COLOR to null,
+    )
+}
+
+/**
+ * UTC millis of the last second of the local day *before* the occurrence at
+ * [beginMillis] in [zone] — the cutoff for truncating a series with UNTIL.
+ * The provider's recurrence engine applies UNTIL coarsely (observed on a
+ * Pixel: an occurrence one second *after* UNTIL was still generated), so the
+ * series must end on the previous day, not one second before the occurrence.
+ * With no sub-daily frequencies that is semantically the same cut.
+ */
+internal fun previousLocalDayEndUtcMillis(beginMillis: Long, zone: ZoneId): Long =
+    Instant.ofEpochMilli(beginMillis).atZone(zone).toLocalDate()
+        .atStartOfDay(zone).toInstant().toEpochMilli() - 1_000L
+
+private const val MILLIS_PER_DAY = 86_400_000L
+
+internal fun Availability.toProviderValue(): Int = when (this) {
+    Availability.Busy -> CalendarContract.Events.AVAILABILITY_BUSY
+    Availability.Free -> CalendarContract.Events.AVAILABILITY_FREE
+    Availability.Tentative -> CalendarContract.Events.AVAILABILITY_TENTATIVE
+}
+
+internal fun AccessLevel.toProviderValue(): Int = when (this) {
+    AccessLevel.Default -> CalendarContract.Events.ACCESS_DEFAULT
+    AccessLevel.Confidential -> CalendarContract.Events.ACCESS_CONFIDENTIAL
+    AccessLevel.Private -> CalendarContract.Events.ACCESS_PRIVATE
+    AccessLevel.Public -> CalendarContract.Events.ACCESS_PUBLIC
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/IcsExportMapper.kt

@@ -0,0 +1,54 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import de.jeanlucmakiola.calendula.domain.EventStatus
+import de.jeanlucmakiola.calendula.domain.ics.IcsEvent
+import de.jeanlucmakiola.calendula.domain.ics.deriveIcsUid
+import de.jeanlucmakiola.calendula.domain.ics.parseRfc2445DurationMillis
+
+/**
+ * Map one Events row (read through [EventExportProjection]) into an [IcsEvent]
+ * for backup. [reminderMinutes] are the row's raw provider reminder offsets and
+ * [calendarName] the display name of its calendar (emitted as
+ * `X-CALENDULA-CALENDAR`). Pure given a [ColumnReader] — JVM-tested with
+ * MapColumnReader.
+ */
+internal fun ColumnReader.toIcsEvent(
+    reminderMinutes: List<Int>,
+    calendarName: String?,
+): IcsEvent {
+    val eventId = getLong(EventExportProjection.IDX_ID)
+    val dtStart = getLong(EventExportProjection.IDX_DTSTART)
+    val rrule = getString(EventExportProjection.IDX_RRULE)?.takeIf { it.isNotBlank() }
+
+    // Recurring rows store DURATION instead of DTEND; reconstruct the end from it
+    // so the writer can render DTEND. A missing/blank both means a zero-length event.
+    val end = when {
+        !isNull(EventExportProjection.IDX_DTEND) -> getLong(EventExportProjection.IDX_DTEND)
+        else -> dtStart + parseRfc2445DurationMillis(getString(EventExportProjection.IDX_DURATION))
+    }
+
+    // STATUS shares value 0 with TENTATIVE, so an absent column must read as Confirmed.
+    val status = if (isNull(EventExportProjection.IDX_STATUS)) {
+        EventStatus.Confirmed
+    } else {
+        mapEventStatus(getInt(EventExportProjection.IDX_STATUS))
+    }
+
+    return IcsEvent(
+        uid = deriveIcsUid(getString(EventExportProjection.IDX_UID), eventId, dtStart),
+        summary = getString(EventExportProjection.IDX_TITLE).orEmpty(),
+        start = dtStart.toKotlinInstantFromEpochMillis(),
+        end = end.toKotlinInstantFromEpochMillis(),
+        isAllDay = getInt(EventExportProjection.IDX_ALL_DAY) != 0,
+        zoneId = getString(EventExportProjection.IDX_EVENT_TIMEZONE)?.takeIf { it.isNotBlank() }
+            ?: "UTC",
+        recurrenceRule = rrule,
+        location = getString(EventExportProjection.IDX_LOCATION),
+        description = getString(EventExportProjection.IDX_DESCRIPTION),
+        reminderMinutes = reminderMinutes,
+        status = status,
+        availability = mapAvailability(getInt(EventExportProjection.IDX_AVAILABILITY)),
+        calendarName = calendarName,
+    )
+}
+

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/ManagedCalendar.kt

@@ -0,0 +1,24 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import de.jeanlucmakiola.calendula.domain.contacts.SpecialDateType
+
+/**
+ * One of the app's special-dates calendars, discovered by the marker stamped in
+ * its `CAL_SYNC2` column — so the mirror can re-adopt its calendars even if the
+ * stored ids in preferences were lost (e.g. an app-data wipe).
+ */
+data class ManagedCalendarRow(val id: Long, val type: SpecialDateType)
+
+/**
+ * A managed event as read back for the sync diff. [uid] is the deterministic
+ * `Events.UID_2445` (`contact-<type>:<lookupKey>@calendula`) the mirror keys on;
+ * [title], [dtStartMillis] and [rrule] are the managed columns compared against
+ * the desired state to decide whether a targeted update is needed.
+ */
+data class ManagedEventRow(
+    val eventId: Long,
+    val uid: String,
+    val title: String,
+    val dtStartMillis: Long,
+    val rrule: String?,
+)

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/Projections.kt

@@ -10,14 +10,32 @@ internal object CalendarProjection {
         CalendarContract.Calendars.ACCOUNT_TYPE,
         CalendarContract.Calendars.CALENDAR_COLOR,
         CalendarContract.Calendars.VISIBLE,
+        CalendarContract.Calendars.CALENDAR_ACCESS_LEVEL,
+        // CalendarContract has no description column; for the local calendars we
+        // own we stash one in CAL_SYNC1 (synced rows put their sync token here,
+        // so the mapper only reads it for local calendars).
+        DESCRIPTION_COLUMN,
+        // The special-dates marker (CAL_SYNC2) — the durable identity the app
+        // uses to recognise its own managed calendars, independent of any
+        // stored preference id (which a backup restore / data wipe can lose).
+        MANAGED_MARKER_COLUMN,
     )
 
+    const val DESCRIPTION_COLUMN: String = CalendarContract.Calendars.CAL_SYNC1
+    const val MANAGED_MARKER_COLUMN: String = CalendarContract.Calendars.CAL_SYNC2
+
+    /** Namespace prefix of every managed-calendar [MANAGED_MARKER_COLUMN] value. */
+    const val MANAGED_MARKER_PREFIX = "calendula.specialdates"
+
     const val IDX_ID = 0
     const val IDX_DISPLAY_NAME = 1
     const val IDX_ACCOUNT_NAME = 2
     const val IDX_ACCOUNT_TYPE = 3
     const val IDX_COLOR = 4
     const val IDX_VISIBLE = 5
+    const val IDX_ACCESS_LEVEL = 6
+    const val IDX_DESCRIPTION = 7
+    const val IDX_MANAGED_MARKER = 8
 }
 
 internal object InstanceProjection {
@@ -60,6 +78,12 @@ internal object EventDetailProjection {
         CalendarContract.Events.ALL_DAY,
         CalendarContract.Events.EVENT_LOCATION,
         CalendarContract.Events.CALENDAR_ID,
+        CalendarContract.Events.STATUS,
+        CalendarContract.Events.AVAILABILITY,
+        CalendarContract.Events.ACCESS_LEVEL,
+        CalendarContract.Events.EVENT_TIMEZONE,
+        CalendarContract.Events.SELF_ATTENDEE_STATUS,
+        CalendarContract.Events.EVENT_COLOR_KEY,
     )
 
     const val IDX_EVENT_ID = 0
@@ -74,6 +98,92 @@ internal object EventDetailProjection {
     const val IDX_ALL_DAY = 9
     const val IDX_LOCATION = 10
     const val IDX_CALENDAR_ID = 11
+    const val IDX_STATUS = 12
+    const val IDX_AVAILABILITY = 13
+    const val IDX_ACCESS_LEVEL = 14
+    const val IDX_EVENT_TIMEZONE = 15
+    const val IDX_SELF_ATTENDEE_STATUS = 16
+    const val IDX_EVENT_COLOR_KEY = 17
+}
+
+/**
+ * Master/one-off Events rows for a whole-calendar backup. Unlike
+ * [EventDetailProjection] this reads `UID_2445` (to keep a row's identity across
+ * backups) and `DURATION` (recurring rows carry it instead of DTEND). Modified-
+ * occurrence and cancelled-exception rows are filtered out by the query
+ * (`ORIGINAL_ID IS NULL`), so RECURRENCE-ID overrides and EXDATEs aren't
+ * exported yet — a documented v1 limit (import skips them too).
+ */
+internal object EventExportProjection {
+    val COLUMNS: Array<String> = arrayOf(
+        CalendarContract.Events._ID,
+        CalendarContract.Events.UID_2445,
+        CalendarContract.Events.TITLE,
+        CalendarContract.Events.DTSTART,
+        CalendarContract.Events.DTEND,
+        CalendarContract.Events.DURATION,
+        CalendarContract.Events.ALL_DAY,
+        CalendarContract.Events.EVENT_TIMEZONE,
+        CalendarContract.Events.RRULE,
+        CalendarContract.Events.EVENT_LOCATION,
+        CalendarContract.Events.DESCRIPTION,
+        CalendarContract.Events.STATUS,
+        CalendarContract.Events.AVAILABILITY,
+        CalendarContract.Events.CALENDAR_ID,
+    )
+
+    const val IDX_ID = 0
+    const val IDX_UID = 1
+    const val IDX_TITLE = 2
+    const val IDX_DTSTART = 3
+    const val IDX_DTEND = 4
+    const val IDX_DURATION = 5
+    const val IDX_ALL_DAY = 6
+    const val IDX_EVENT_TIMEZONE = 7
+    const val IDX_RRULE = 8
+    const val IDX_LOCATION = 9
+    const val IDX_DESCRIPTION = 10
+    const val IDX_STATUS = 11
+    const val IDX_AVAILABILITY = 12
+    const val IDX_CALENDAR_ID = 13
+}
+
+/**
+ * Master/one-off Events rows matched by a full-text search. Like
+ * [EventExportProjection] it reads the Events table directly (so the search is
+ * unbounded in time), carrying DURATION for recurring rows that have no DTEND.
+ * Colour folds the calendar fallback like [InstanceProjection].
+ */
+internal object SearchProjection {
+    val COLUMNS: Array<String> = arrayOf(
+        CalendarContract.Events._ID,
+        CalendarContract.Events.CALENDAR_ID,
+        CalendarContract.Events.TITLE,
+        CalendarContract.Events.DTSTART,
+        CalendarContract.Events.DTEND,
+        CalendarContract.Events.DURATION,
+        CalendarContract.Events.ALL_DAY,
+        CalendarContract.Events.EVENT_COLOR,
+        CalendarContract.Events.CALENDAR_COLOR,
+        CalendarContract.Events.EVENT_LOCATION,
+        // Recurrence markers: a non-empty RRULE or RDATE means the result should
+        // display its nearest occurrence, not the series-start DTSTART.
+        CalendarContract.Events.RRULE,
+        CalendarContract.Events.RDATE,
+    )
+
+    const val IDX_ID = 0
+    const val IDX_CALENDAR_ID = 1
+    const val IDX_TITLE = 2
+    const val IDX_DTSTART = 3
+    const val IDX_DTEND = 4
+    const val IDX_DURATION = 5
+    const val IDX_ALL_DAY = 6
+    const val IDX_EVENT_COLOR = 7
+    const val IDX_CALENDAR_COLOR = 8
+    const val IDX_LOCATION = 9
+    const val IDX_RRULE = 10
+    const val IDX_RDATE = 11
 }
 
 internal object AttendeeProjection {
@@ -81,11 +191,25 @@ internal object AttendeeProjection {
         CalendarContract.Attendees.ATTENDEE_NAME,
         CalendarContract.Attendees.ATTENDEE_EMAIL,
         CalendarContract.Attendees.ATTENDEE_STATUS,
+        CalendarContract.Attendees.ATTENDEE_RELATIONSHIP,
+        CalendarContract.Attendees.ATTENDEE_TYPE,
     )
 
     const val IDX_NAME = 0
     const val IDX_EMAIL = 1
     const val IDX_STATUS = 2
+    const val IDX_RELATIONSHIP = 3
+    const val IDX_TYPE = 4
+}
+
+internal object ReminderProjection {
+    val COLUMNS: Array<String> = arrayOf(
+        CalendarContract.Reminders.MINUTES,
+        CalendarContract.Reminders.METHOD,
+    )
+
+    const val IDX_MINUTES = 0
+    const val IDX_METHOD = 1
 }
 
 internal object Fallbacks {

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/SearchMapper.kt

@@ -0,0 +1,43 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.domain.ics.parseRfc2445DurationMillis
+
+/**
+ * Map an Events-table row (a search hit) to an [EventInstance]. Unlike the
+ * Instances query this reads the series master, so there is no instance id (the
+ * event id stands in as the list key) and recurring rows carry DURATION instead
+ * of DTEND — reconstruct the end the same way the `.ics` export does.
+ */
+internal fun ColumnReader.toSearchResult(): EventInstance? {
+    // A pre-1970 series anchor is a legitimately negative epoch-millis DTSTART
+    // (see EventDetailMapper / issue #34); drop only a genuinely absent one, so
+    // long-running birthdays/anniversaries still surface in search.
+    if (isNull(SearchProjection.IDX_DTSTART)) return null
+    val dtStart = getLong(SearchProjection.IDX_DTSTART)
+    val end = when {
+        !isNull(SearchProjection.IDX_DTEND) -> getLong(SearchProjection.IDX_DTEND)
+        else -> dtStart + parseRfc2445DurationMillis(getString(SearchProjection.IDX_DURATION))
+    }.coerceAtLeast(dtStart)
+
+    val rawTitle = getString(SearchProjection.IDX_TITLE)
+    val title = if (rawTitle.isNullOrEmpty()) Fallbacks.UNTITLED_EVENT else rawTitle
+    val color = if (isNull(SearchProjection.IDX_EVENT_COLOR)) {
+        getInt(SearchProjection.IDX_CALENDAR_COLOR)
+    } else {
+        getInt(SearchProjection.IDX_EVENT_COLOR)
+    }
+    val eventId = getLong(SearchProjection.IDX_ID)
+
+    return EventInstance(
+        instanceId = eventId,
+        eventId = eventId,
+        calendarId = getLong(SearchProjection.IDX_CALENDAR_ID),
+        title = title,
+        start = dtStart.toKotlinInstantFromEpochMillis(),
+        end = end.toKotlinInstantFromEpochMillis(),
+        isAllDay = getInt(SearchProjection.IDX_ALL_DAY) != 0,
+        color = color,
+        location = getString(SearchProjection.IDX_LOCATION),
+    )
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/contacts/AndroidSpecialDatesCalendarSpec.kt

@@ -0,0 +1,42 @@
+package de.jeanlucmakiola.calendula.data.contacts
+
+import android.content.Context
+import dagger.hilt.android.qualifiers.ApplicationContext
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.data.calendar.CalendarColorPalette
+import de.jeanlucmakiola.calendula.domain.contacts.SpecialDateType
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Resolves the localized calendar names/templates and per-type colours the
+ * mirror creates its calendars with. The colours are picked from the shared
+ * palette so managed calendars look native alongside user calendars.
+ */
+@Singleton
+class AndroidSpecialDatesCalendarSpec @Inject constructor(
+    @ApplicationContext private val context: Context,
+) : SpecialDatesCalendarSpec {
+
+    override fun displayName(type: SpecialDateType): String = context.getString(
+        when (type) {
+            SpecialDateType.Birthday -> R.string.special_dates_calendar_birthday
+            SpecialDateType.Anniversary -> R.string.special_dates_calendar_anniversary
+            SpecialDateType.Custom -> R.string.special_dates_calendar_custom
+        },
+    )
+
+    override fun defaultTitleTemplate(type: SpecialDateType): String = context.getString(
+        when (type) {
+            SpecialDateType.Birthday -> R.string.special_dates_default_title_birthday
+            SpecialDateType.Anniversary -> R.string.special_dates_default_title_anniversary
+            SpecialDateType.Custom -> R.string.special_dates_default_title_custom
+        },
+    )
+
+    override fun color(type: SpecialDateType): Int = when (type) {
+        SpecialDateType.Birthday -> CalendarColorPalette.Purple
+        SpecialDateType.Anniversary -> CalendarColorPalette.Red
+        SpecialDateType.Custom -> CalendarColorPalette.Blue
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/contacts/ContactSpecialDatesDataSource.kt

@@ -0,0 +1,105 @@
+package de.jeanlucmakiola.calendula.data.contacts
+
+import android.Manifest
+import android.content.Context
+import android.content.pm.PackageManager
+import android.provider.ContactsContract
+import android.provider.ContactsContract.CommonDataKinds.Event
+import android.util.Log
+import androidx.core.content.ContextCompat
+import dagger.hilt.android.qualifiers.ApplicationContext
+import de.jeanlucmakiola.calendula.domain.contacts.ContactSpecialDate
+import de.jeanlucmakiola.calendula.domain.contacts.SpecialDateType
+import de.jeanlucmakiola.calendula.domain.contacts.managedUid
+import de.jeanlucmakiola.calendula.domain.contacts.parseContactEventDate
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Reads the dated `Event` rows (birthdays, anniversaries, custom dates) of the
+ * device's contacts. Read-only and offline — the one-way source for the
+ * special-dates mirror. Requires `READ_CONTACTS`; returns an empty list when
+ * the permission is absent so the sync can degrade to a stalled state rather
+ * than crash.
+ */
+interface ContactSpecialDatesDataSource {
+    fun hasPermission(): Boolean
+
+    /** All usable contact special-dates, deduplicated per contact and type. */
+    fun readSpecialDates(): List<ContactSpecialDate>
+}
+
+/** Whether `READ_CONTACTS` is granted — the gate for every contacts read. */
+fun Context.hasContactsPermission(): Boolean =
+    ContextCompat.checkSelfPermission(this, Manifest.permission.READ_CONTACTS) ==
+        PackageManager.PERMISSION_GRANTED
+
+/** Map a `ContactsContract` event `TYPE` to our calendar bucket. */
+internal fun specialDateTypeForRawEventType(type: Int): SpecialDateType = when (type) {
+    Event.TYPE_BIRTHDAY -> SpecialDateType.Birthday
+    Event.TYPE_ANNIVERSARY -> SpecialDateType.Anniversary
+    else -> SpecialDateType.Custom
+}
+
+@Singleton
+class AndroidContactSpecialDatesDataSource @Inject constructor(
+    @ApplicationContext private val context: Context,
+) : ContactSpecialDatesDataSource {
+
+    override fun hasPermission(): Boolean = context.hasContactsPermission()
+
+    override fun readSpecialDates(): List<ContactSpecialDate> {
+        if (!hasPermission()) return emptyList()
+        val resolver = context.contentResolver
+        // A contact can carry the same date more than once (multiple raw contacts
+        // under one aggregate); dedup on the mirror's reconciliation key so exact
+        // duplicates collapse while genuinely distinct dates (two custom events on
+        // one contact) are all kept. Ordered by Data._ID so which of two truly
+        // conflicting rows wins is stable across syncs (no event ping-pong).
+        val seen = HashSet<String>()
+        val result = ArrayList<ContactSpecialDate>()
+        runCatching {
+            resolver.query(
+                ContactsContract.Data.CONTENT_URI,
+                PROJECTION,
+                "${ContactsContract.Data.MIMETYPE} = ?",
+                arrayOf(Event.CONTENT_ITEM_TYPE),
+                "${ContactsContract.Data._ID} ASC",
+            )?.use { c ->
+                val idxDate = c.getColumnIndexOrThrow(Event.START_DATE)
+                val idxType = c.getColumnIndexOrThrow(Event.TYPE)
+                val idxLabel = c.getColumnIndexOrThrow(Event.LABEL)
+                val idxLookup = c.getColumnIndexOrThrow(ContactsContract.Data.LOOKUP_KEY)
+                val idxName = c.getColumnIndexOrThrow(ContactsContract.Data.DISPLAY_NAME_PRIMARY)
+                while (c.moveToNext()) {
+                    val lookup = c.getString(idxLookup)?.takeIf { it.isNotEmpty() } ?: continue
+                    val parts = parseContactEventDate(c.getString(idxDate)) ?: continue
+                    val type = specialDateTypeForRawEventType(c.getInt(idxType))
+                    val date = ContactSpecialDate(
+                        lookupKey = lookup,
+                        displayName = c.getString(idxName)?.trim().orEmpty(),
+                        type = type,
+                        month = parts.month,
+                        day = parts.day,
+                        year = parts.year,
+                        label = c.getString(idxLabel)?.takeIf { it.isNotBlank() },
+                    )
+                    if (seen.add(date.managedUid())) result += date
+                }
+            }
+        }.onFailure { Log.w(TAG, "Reading contact special-dates failed", it) }
+        return result
+    }
+
+    private companion object {
+        const val TAG = "ContactSpecialDates"
+
+        val PROJECTION = arrayOf(
+            ContactsContract.Data.LOOKUP_KEY,
+            ContactsContract.Data.DISPLAY_NAME_PRIMARY,
+            Event.START_DATE,
+            Event.TYPE,
+            Event.LABEL,
+        )
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/contacts/SpecialDatesScheduler.kt

@@ -0,0 +1,135 @@
+package de.jeanlucmakiola.calendula.data.contacts
+
+import android.content.Context
+import android.util.Log
+import androidx.work.CoroutineWorker
+import androidx.work.Data
+import androidx.work.ExistingPeriodicWorkPolicy
+import androidx.work.ExistingWorkPolicy
+import androidx.work.OneTimeWorkRequestBuilder
+import androidx.work.PeriodicWorkRequestBuilder
+import androidx.work.WorkManager
+import androidx.work.WorkerParameters
+import dagger.hilt.EntryPoint
+import dagger.hilt.InstallIn
+import dagger.hilt.android.EntryPointAccessors
+import dagger.hilt.components.SingletonComponent
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import de.jeanlucmakiola.calendula.data.prefs.SpecialDatesStalledReason
+import kotlinx.coroutines.flow.first
+import java.util.concurrent.TimeUnit
+
+/**
+ * Schedules the contact special-dates mirror. Birthdays change rarely, so this
+ * is deliberately cheap: a **daily** periodic reconcile, plus an immediate run
+ * on enable / "Sync now" and a debounced one when the app is foregrounded. No
+ * ContentObserver — it would need the process alive and buys almost nothing for
+ * once-a-year events. Everything stays offline (local contacts → local calendar).
+ */
+object SpecialDatesScheduler {
+
+    private const val WORK_NAME = "special-dates-sync"
+    private const val WORK_NAME_NOW = "special-dates-sync-now"
+    private const val WORK_NAME_FOREGROUND = "special-dates-sync-foreground"
+    private const val KEY_FOREGROUND = "foreground"
+
+    /** Enqueue (or cancel) the daily periodic reconcile to match [enabled]. */
+    fun apply(context: Context, enabled: Boolean) {
+        val workManager = WorkManager.getInstance(context)
+        if (!enabled) {
+            workManager.cancelUniqueWork(WORK_NAME)
+            workManager.cancelUniqueWork(WORK_NAME_NOW)
+            workManager.cancelUniqueWork(WORK_NAME_FOREGROUND)
+            return
+        }
+        val request = PeriodicWorkRequestBuilder<SpecialDatesSyncWorker>(1, TimeUnit.DAYS)
+            // Delay the first periodic run so it never overlaps an immediate run.
+            .setInitialDelay(1, TimeUnit.DAYS)
+            .build()
+        workManager.enqueueUniquePeriodicWork(WORK_NAME, ExistingPeriodicWorkPolicy.UPDATE, request)
+    }
+
+    /**
+     * Run one reconcile immediately. [foreground] runs (the app resuming) are
+     * debounced inside the worker and use their own work name, so a frequent
+     * foreground resync can never REPLACE — and swallow — a pending enable /
+     * "Sync now" run, which always syncs. The engine serializes the two if they
+     * overlap.
+     */
+    fun runNow(context: Context, foreground: Boolean = false) {
+        val request = OneTimeWorkRequestBuilder<SpecialDatesSyncWorker>()
+            .setInputData(Data.Builder().putBoolean(KEY_FOREGROUND, foreground).build())
+            .build()
+        val name = if (foreground) WORK_NAME_FOREGROUND else WORK_NAME_NOW
+        WorkManager.getInstance(context)
+            .enqueueUniqueWork(name, ExistingWorkPolicy.REPLACE, request)
+    }
+
+    internal const val INPUT_FOREGROUND = KEY_FOREGROUND
+}
+
+/**
+ * Runs the [SpecialDatesSyncEngine]. Pulls its collaborators through a Hilt
+ * [EntryPoint] so it works under WorkManager's default worker factory. Records
+ * the run for the settings status line; a missing permission parks the feature
+ * in a stalled state (surfaced in settings) rather than retrying forever.
+ */
+class SpecialDatesSyncWorker(
+    appContext: Context,
+    params: WorkerParameters,
+) : CoroutineWorker(appContext, params) {
+
+    @EntryPoint
+    @InstallIn(SingletonComponent::class)
+    interface Deps {
+        fun settingsPrefs(): SettingsPrefs
+        fun syncEngine(): SpecialDatesSyncEngine
+    }
+
+    override suspend fun doWork(): Result {
+        val deps = EntryPointAccessors.fromApplication(applicationContext, Deps::class.java)
+        val prefs = deps.settingsPrefs()
+
+        val now = System.currentTimeMillis()
+        // A foreground resume can fire often — skip if we synced recently.
+        val foreground = inputData.getBoolean(SpecialDatesScheduler.INPUT_FOREGROUND, false)
+        if (foreground && now - prefs.specialDatesLastForegroundSync.first() < FOREGROUND_DEBOUNCE_MILLIS) {
+            return Result.success()
+        }
+
+        return try {
+            when (val result = deps.syncEngine().sync()) {
+                // The engine re-checks the toggle, so already-queued work never
+                // revives a disabled feature; don't record a run either.
+                SpecialDatesSyncResult.Disabled -> return Result.success()
+                else -> {
+                    val stalled = if (result == SpecialDatesSyncResult.PermissionMissing) {
+                        SpecialDatesStalledReason.PermissionRevoked
+                    } else {
+                        null
+                    }
+                    prefs.recordSpecialDatesRun(now, stalled)
+                }
+            }
+            if (foreground) prefs.setSpecialDatesLastForegroundSync(now)
+            Result.success()
+        } catch (e: SecurityException) {
+            // A revoked calendar/contacts permission won't fix itself on retry —
+            // park the feature in a stalled state (surfaced in settings) instead
+            // of retrying with backoff forever.
+            Log.w(TAG, "Special-dates sync lacks a required permission", e)
+            prefs.recordSpecialDatesRun(now, SpecialDatesStalledReason.PermissionRevoked)
+            Result.success()
+        } catch (e: Exception) {
+            Log.w(TAG, "Special-dates sync failed", e)
+            Result.retry()
+        }
+    }
+
+    companion object {
+        private const val TAG = "SpecialDatesSync"
+
+        /** Skip a foreground-triggered sync if one ran within this window (4h). */
+        private const val FOREGROUND_DEBOUNCE_MILLIS = 4L * 60 * 60 * 1000
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/contacts/SpecialDatesSyncEngine.kt

@@ -0,0 +1,304 @@
+package de.jeanlucmakiola.calendula.data.contacts
+
+import android.provider.CalendarContract
+import de.jeanlucmakiola.calendula.data.calendar.CalendarDataSource
+import de.jeanlucmakiola.calendula.data.calendar.ManagedEventRow
+import de.jeanlucmakiola.calendula.data.calendar.toWriteTimes
+import de.jeanlucmakiola.calendula.data.prefs.CalendarReminderOverride
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import de.jeanlucmakiola.calendula.domain.Availability
+import de.jeanlucmakiola.calendula.domain.EventForm
+import de.jeanlucmakiola.calendula.domain.RecurrenceFreq
+import de.jeanlucmakiola.calendula.domain.SimpleRecurrence
+import de.jeanlucmakiola.calendula.domain.contacts.ContactSpecialDate
+import de.jeanlucmakiola.calendula.domain.contacts.SpecialDateType
+import de.jeanlucmakiola.calendula.domain.contacts.anchorDate
+import de.jeanlucmakiola.calendula.domain.contacts.managedUid
+import de.jeanlucmakiola.calendula.domain.contacts.renderSpecialDateTitle
+import de.jeanlucmakiola.calendula.domain.toRRule
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
+import java.time.ZoneId
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/** Outcome of one mirror reconcile, reported back so the worker can record status. */
+enum class SpecialDatesSyncResult { Success, Disabled, PermissionMissing }
+
+/**
+ * Localized, per-type presentation the engine needs but can't derive purely
+ * (calendar display name, colour, and the default title template). Kept behind
+ * an interface so the engine's diff stays unit-testable without Android
+ * resources.
+ */
+interface SpecialDatesCalendarSpec {
+    fun displayName(type: SpecialDateType): String
+    fun color(type: SpecialDateType): Int
+    fun defaultTitleTemplate(type: SpecialDateType): String
+}
+
+/**
+ * The stored title template for [type], falling back to the localized default
+ * when blank/absent — the one resolution rule shared by the sync (what gets
+ * written) and the settings editor (what gets shown).
+ */
+fun SpecialDatesCalendarSpec.resolveTitleTemplate(
+    type: SpecialDateType,
+    stored: Map<SpecialDateType, String>,
+): String = stored[type]?.takeIf { it.isNotBlank() } ?: defaultTitleTemplate(type)
+
+/**
+ * Mirrors contact birthdays/anniversaries/custom dates into local calendars,
+ * one per type. Every reconcile is an idempotent diff keyed on the deterministic
+ * `UID_2445` ([managedEventUid]): new contacts are inserted (seeding user-owned
+ * fields once), changed contacts get a *targeted* managed-column update, and
+ * removed contacts are deleted — so a user's own edits (reminders, location,
+ * notes) are never clobbered. See docs/design/contact-special-dates.md.
+ */
+@Singleton
+class SpecialDatesSyncEngine @Inject constructor(
+    private val contacts: ContactSpecialDatesDataSource,
+    private val calendars: CalendarDataSource,
+    private val prefs: SettingsPrefs,
+    private val spec: SpecialDatesCalendarSpec,
+) {
+
+    // Serializes calendar-lifecycle work: two overlapping syncs (the daily job
+    // racing a "Sync now"/foreground run) would each see no managed calendar and
+    // both create one; a teardown racing an in-flight sync would delete calendars
+    // the sync then recreates. Holding this for the whole of sync()/teardown()
+    // makes those check-then-act sequences atomic, and — because sync() re-reads
+    // the enabled flag inside the lock — a teardown always wins the race.
+    private val lifecycleMutex = Mutex()
+
+    /**
+     * Reconcile every enabled type against the device's contacts. Returns why it
+     * stopped early (disabled / permission gone) or [SpecialDatesSyncResult.Success].
+     */
+    suspend fun sync(): SpecialDatesSyncResult = lifecycleMutex.withLock {
+        if (!prefs.specialDatesEnabled.first()) return SpecialDatesSyncResult.Disabled
+        if (!contacts.hasPermission()) return SpecialDatesSyncResult.PermissionMissing
+
+        val enabledTypes = prefs.specialDatesTypes.first()
+        val calendarByType = reconcileCalendars(enabledTypes)
+
+        val desiredByType = contacts.readSpecialDates().groupBy { it.type }
+        val reminderCtx = readReminderContext()
+        val templates = prefs.specialDatesTitleTemplates.first()
+        val showYear = prefs.specialDatesShowYear.first()
+
+        calendarByType.forEach { (type, calendarId) ->
+            val template = spec.resolveTitleTemplate(type, templates)
+            syncType(
+                calendarId = calendarId,
+                type = type,
+                contactsOfType = desiredByType[type].orEmpty(),
+                template = template,
+                showYear = showYear,
+                reminderCtx = reminderCtx,
+            )
+        }
+        SpecialDatesSyncResult.Success
+    }
+
+    /**
+     * Set the reminder default for a type's managed calendar and apply it to
+     * **all** its existing events too (not just future ones) — for managed
+     * calendars the reminder is a calendar-level setting. Persists the per-calendar
+     * all-day override so new events keep matching. No-op if the calendar for
+     * [type] doesn't exist yet.
+     */
+    suspend fun applyReminders(type: SpecialDateType, override: CalendarReminderOverride) {
+        val calendarId = prefs.specialDatesCalendars.first()[type] ?: return
+        prefs.setCalendarAllDayReminderOverride(calendarId, override)
+        val minutes = when (override) {
+            CalendarReminderOverride.Inherit -> prefs.defaultAllDayReminderMinutes.first()
+            CalendarReminderOverride.None -> emptyList()
+            is CalendarReminderOverride.Minutes -> override.minutes
+        }
+        calendars.applyManagedCalendarReminders(
+            calendarId = calendarId,
+            allDayReminderTimeMinutes = prefs.allDayReminderTimeMinutes.first(),
+            minutes = minutes,
+        )
+    }
+
+    /** Delete every managed calendar and forget its id — used when the feature is turned off. */
+    suspend fun teardown() = lifecycleMutex.withLock {
+        calendars.findManagedCalendars().forEach { calendars.deleteCalendar(it.id) }
+        SpecialDateType.entries.forEach { prefs.setSpecialDatesCalendarId(it, null) }
+    }
+
+    /**
+     * Ensure each enabled type has exactly one managed calendar (adopting an
+     * existing one, or the stored id if it still exists, else creating one) and
+     * that disabled types have none. Returns the calendar id per enabled type.
+     */
+    private suspend fun reconcileCalendars(enabledTypes: Set<SpecialDateType>): Map<SpecialDateType, Long> {
+        val foundByType = calendars.findManagedCalendars()
+            .groupBy({ it.type }, { it.id })
+            .mapValues { it.value.first() }
+        val stored = prefs.specialDatesCalendars.first()
+        val result = LinkedHashMap<SpecialDateType, Long>()
+        for (type in SpecialDateType.entries) {
+            // A stored id counts only if the calendar still exists (the user may
+            // have deleted it in system settings); otherwise adopt a found one.
+            val existingId = stored[type]?.takeIf { id -> foundByType.containsValue(id) }
+                ?: foundByType[type]
+            if (type in enabledTypes) {
+                val id = existingId ?: createCalendar(type)
+                if (stored[type] != id) prefs.setSpecialDatesCalendarId(type, id)
+                result[type] = id
+            } else {
+                if (existingId != null) calendars.deleteCalendar(existingId)
+                if (stored.containsKey(type)) prefs.setSpecialDatesCalendarId(type, null)
+            }
+        }
+        return result
+    }
+
+    private suspend fun createCalendar(type: SpecialDateType): Long {
+        // reconcileCalendars persists the id — the single place ids are recorded.
+        val id = calendars.createManagedCalendar(spec.displayName(type), spec.color(type), type)
+        // Seed a useful all-day reminder default (on the day + a week before), so
+        // birthdays get lead time out of the box. Per-calendar, user-adjustable —
+        // only set when the user hasn't already configured this calendar.
+        if (!prefs.perCalendarAllDayReminderOverride.first().containsKey(id)) {
+            prefs.setCalendarAllDayReminderOverride(
+                id,
+                CalendarReminderOverride.Minutes(DEFAULT_REMINDER_MINUTES),
+            )
+        }
+        return id
+    }
+
+    private suspend fun syncType(
+        calendarId: Long,
+        type: SpecialDateType,
+        contactsOfType: List<ContactSpecialDate>,
+        template: String,
+        showYear: Boolean,
+        reminderCtx: ReminderContext,
+    ) {
+        val built = contactsOfType.map { sd ->
+            buildManagedEvent(calendarId, type, sd, template, showYear, reminderCtx)
+        }
+        val diff = diffManagedEvents(built.map { it.desired }, calendars.queryManagedEvents(calendarId))
+        val formByUid = built.associate { it.desired.uid to it.form }
+        diff.insertUids.forEach { uid ->
+            calendars.insertManagedEvent(formByUid.getValue(uid), uid, reminderCtx.allDayTimeMinutes)
+        }
+        diff.updates.forEach { calendars.updateManagedFields(it.eventId, it.columns) }
+        diff.deleteEventIds.forEach { calendars.deleteEvent(it) }
+    }
+
+    private fun buildManagedEvent(
+        calendarId: Long,
+        type: SpecialDateType,
+        sd: ContactSpecialDate,
+        template: String,
+        showYear: Boolean,
+        reminderCtx: ReminderContext,
+    ): BuiltManagedEvent {
+        val anchor = sd.anchorDate()
+        val start = LocalDateTime(anchor, LocalTime(0, 0))
+        // The source year is static and correct on every occurrence (unlike age).
+        val year = if (showYear) sd.year else null
+        val title = renderSpecialDateTitle(template, sd.displayName, year)
+        val form = EventForm(
+            calendarId = calendarId,
+            title = title,
+            isAllDay = true,
+            start = start,
+            end = start,
+            reminders = reminderCtx.resolveAllDay(calendarId),
+            availability = Availability.Free,
+            rrule = YEARLY_RRULE,
+        )
+        val dtStartMillis = form.toWriteTimes(ZoneId.systemDefault()).dtStartMillis
+        return BuiltManagedEvent(
+            desired = ManagedEventDesired(
+                uid = sd.managedUid(),
+                title = title,
+                dtStartMillis = dtStartMillis,
+                rrule = YEARLY_RRULE,
+            ),
+            form = form,
+        )
+    }
+
+    // Managed events are always all-day, so only the all-day defaults apply.
+    private suspend fun readReminderContext(): ReminderContext = ReminderContext(
+        allDayGlobal = prefs.defaultAllDayReminderMinutes.first(),
+        allDayOverrides = prefs.perCalendarAllDayReminderOverride.first(),
+        allDayTimeMinutes = prefs.allDayReminderTimeMinutes.first(),
+    )
+
+    private data class ReminderContext(
+        val allDayGlobal: List<Int>,
+        val allDayOverrides: Map<Long, List<Int>>,
+        val allDayTimeMinutes: Int,
+    ) {
+        /** Same semantics as `resolveDefaultReminder`: present-empty = explicit none. */
+        fun resolveAllDay(calendarId: Long): List<Int> =
+            allDayOverrides[calendarId] ?: allDayGlobal
+    }
+
+    private data class BuiltManagedEvent(val desired: ManagedEventDesired, val form: EventForm)
+
+    private companion object {
+        /** "On the day" (0) + one week before (7 days), as all-day lead minutes. */
+        val DEFAULT_REMINDER_MINUTES = listOf(0, 7 * 24 * 60)
+        val YEARLY_RRULE = SimpleRecurrence(freq = RecurrenceFreq.Yearly).toRRule()
+    }
+}
+
+/** The managed columns of a desired event, compared against the existing row. */
+internal data class ManagedEventDesired(
+    val uid: String,
+    val title: String,
+    val dtStartMillis: Long,
+    val rrule: String?,
+)
+
+internal data class ManagedFieldUpdate(val eventId: Long, val columns: Map<String, Any?>)
+
+internal data class ManagedDiff(
+    val insertUids: List<String>,
+    val updates: List<ManagedFieldUpdate>,
+    val deleteEventIds: List<Long>,
+)
+
+/**
+ * The idempotent diff at the heart of the mirror, keyed on `UID_2445`:
+ * desired-not-existing → insert, existing-not-desired → delete, and for events
+ * in both only the *changed* managed columns (title/dtstart/rrule) are emitted —
+ * so a re-run with no contact changes produces nothing, and a managed update
+ * never touches user-owned columns or reminder rows. Pure, so it's unit-tested.
+ */
+internal fun diffManagedEvents(
+    desired: List<ManagedEventDesired>,
+    existing: List<ManagedEventRow>,
+): ManagedDiff {
+    val desiredByUid = desired.associateBy { it.uid }
+    val existingByUid = existing.associateBy { it.uid }
+    val insertUids = desired.filter { it.uid !in existingByUid }.map { it.uid }
+    val deleteEventIds = existing.filter { it.uid !in desiredByUid }.map { it.eventId }
+    val updates = buildList {
+        for (d in desired) {
+            val row = existingByUid[d.uid] ?: continue
+            val columns = buildMap<String, Any?> {
+                if (row.title != d.title) put(CalendarContract.Events.TITLE, d.title)
+                if (row.dtStartMillis != d.dtStartMillis) {
+                    put(CalendarContract.Events.DTSTART, d.dtStartMillis)
+                }
+                if (row.rrule != d.rrule) put(CalendarContract.Events.RRULE, d.rrule)
+            }
+            if (columns.isNotEmpty()) add(ManagedFieldUpdate(row.eventId, columns))
+        }
+    }
+    return ManagedDiff(insertUids, updates, deleteEventIds)
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/crash/CrashReporter.kt

@@ -0,0 +1,188 @@
+package de.jeanlucmakiola.calendula.data.crash
+
+import android.content.Context
+import android.content.pm.PackageInfo
+import android.os.Build
+import androidx.core.content.pm.PackageInfoCompat
+import java.io.File
+import java.io.PrintWriter
+import java.io.StringWriter
+import java.time.Instant
+import java.time.ZoneId
+import java.time.format.DateTimeFormatter
+import java.util.Locale
+
+/**
+ * Privacy-respecting crash capture (prod-readiness item 10). On an uncaught
+ * exception it writes a self-contained report to the app's private storage and
+ * then chains to the platform's default handler, so the process still dies
+ * normally (and the OS shows its own "stopped" dialog). Nothing is uploaded —
+ * the app holds no `INTERNET` permission. The user submits the report later,
+ * by hand, as a Gitea issue (see the ui/crash surfaces).
+ *
+ * The report is built from a fixed [CrashContext] allowlist — app/Android/device
+ * version, locale, time, and the stack trace — and **nothing else**: no device
+ * identifiers, no account names, no calendar/event content, no logcat. The user
+ * is always shown the full text before it leaves the device.
+ */
+object CrashReporter {
+
+    /**
+     * Install the handler. Called first thing in `CalendulaApp.onCreate()` so it
+     * also catches crashes during startup. The handler swallows nothing — it
+     * persists, then delegates to the previously-registered handler.
+     */
+    fun install(context: Context) {
+        val appContext = context.applicationContext
+        val previous = Thread.getDefaultUncaughtExceptionHandler()
+        Thread.setDefaultUncaughtExceptionHandler { thread, throwable ->
+            // Capturing must never mask the original crash, so guard every step.
+            runCatching {
+                val now = System.currentTimeMillis()
+                writeReport(appContext, buildCrashReport(CrashContext.from(appContext), throwable, now))
+                recordCrashTime(appContext, now)
+            }
+            previous?.uncaughtException(thread, throwable)
+        }
+    }
+
+    /** The persisted report from the last crash, or null if there is none. */
+    fun pendingReport(context: Context): String? {
+        val file = reportFile(context)
+        return if (file.exists()) runCatching { file.readText() }.getOrNull()?.takeIf { it.isNotBlank() } else null
+    }
+
+    /**
+     * Whether to surface the report unprompted (on the next launch): a report
+     * exists and the user hasn't already waved this one away. Settings reaches
+     * the report via [pendingReport] regardless, so "Not now" only stops the
+     * auto-prompt — it doesn't discard the report.
+     */
+    fun shouldPrompt(context: Context): Boolean =
+        reportFile(context).exists() && !dismissedFile(context).exists()
+
+    /** Stop auto-prompting for the current report without discarding it. */
+    fun dismissPrompt(context: Context) {
+        runCatching { dismissedFile(context).apply { parentFile?.mkdirs() }.writeText("") }
+    }
+
+    /** Drop the persisted report once the user has reported it (or from Settings). */
+    fun clearReport(context: Context) {
+        runCatching { reportFile(context).delete() }
+        runCatching { dismissedFile(context).delete() }
+    }
+
+    /**
+     * Whether the app appears to be in a startup crash-loop: at least
+     * [LOOP_THRESHOLD] crashes inside [LOOP_WINDOW_MS]. In that case the main UI
+     * can't be trusted to start, so the caller routes straight to the standalone
+     * report screen instead of re-entering the crashing graph.
+     */
+    fun isCrashLoop(context: Context): Boolean {
+        val times = readCrashTimes(context)
+        if (times.size < LOOP_THRESHOLD) return false
+        val recent = times.sortedDescending()
+        return recent[0] - recent[LOOP_THRESHOLD - 1] <= LOOP_WINDOW_MS
+    }
+
+    /**
+     * Mark the app as having started successfully, resetting the loop counter so
+     * an ordinary single crash much later never trips loop detection. The
+     * pending report itself is kept — only the timing trail is cleared.
+     */
+    fun markHealthy(context: Context) {
+        runCatching { timesFile(context).delete() }
+    }
+
+    // --- persistence -------------------------------------------------------
+
+    private fun writeReport(context: Context, report: String) {
+        val file = reportFile(context).apply { parentFile?.mkdirs() }
+        file.writeText(report.take(MAX_REPORT_CHARS))
+        // A fresh crash should prompt again, even if the previous one was waved away.
+        runCatching { dismissedFile(context).delete() }
+    }
+
+    private fun recordCrashTime(context: Context, nowMillis: Long) {
+        val kept = (readCrashTimes(context) + nowMillis).takeLast(MAX_TIMES)
+        timesFile(context).apply { parentFile?.mkdirs() }
+            .writeText(kept.joinToString("\n"))
+    }
+
+    private fun readCrashTimes(context: Context): List<Long> {
+        val file = timesFile(context)
+        if (!file.exists()) return emptyList()
+        return runCatching { file.readLines().mapNotNull { it.trim().toLongOrNull() } }.getOrDefault(emptyList())
+    }
+
+    private fun crashDir(context: Context) = File(context.filesDir, CRASH_DIR)
+    private fun reportFile(context: Context) = File(crashDir(context), REPORT_FILE)
+    private fun timesFile(context: Context) = File(crashDir(context), TIMES_FILE)
+    private fun dismissedFile(context: Context) = File(crashDir(context), DISMISSED_FILE)
+
+    private const val CRASH_DIR = "crash"
+    private const val REPORT_FILE = "last_crash.txt"
+    private const val TIMES_FILE = "crash_times.txt"
+    private const val DISMISSED_FILE = "dismissed"
+    private const val MAX_TIMES = 5
+    private const val MAX_REPORT_CHARS = 64 * 1024
+    private const val LOOP_THRESHOLD = 2
+    private const val LOOP_WINDOW_MS = 10_000L
+}
+
+/**
+ * The allowlist of non-personal facts that go into a crash report. Built from
+ * [Build] and the app's own [PackageInfo]; deliberately holds no identifiers.
+ */
+data class CrashContext(
+    val appVersionName: String,
+    val appVersionCode: Long,
+    val sdkInt: Int,
+    val androidRelease: String,
+    val manufacturer: String,
+    val model: String,
+    val locale: String,
+) {
+    companion object {
+        fun from(context: Context): CrashContext {
+            val pkg = runCatching {
+                context.packageManager.getPackageInfo(context.packageName, 0)
+            }.getOrNull()
+            return CrashContext(
+                appVersionName = pkg?.versionName ?: "?",
+                appVersionCode = pkg?.let { PackageInfoCompat.getLongVersionCode(it) } ?: 0L,
+                sdkInt = Build.VERSION.SDK_INT,
+                androidRelease = Build.VERSION.RELEASE ?: "?",
+                manufacturer = Build.MANUFACTURER ?: "?",
+                model = Build.MODEL ?: "?",
+                locale = Locale.getDefault().toLanguageTag(),
+            )
+        }
+    }
+}
+
+/**
+ * Render a crash report from the [ctx] allowlist, the [throwable]'s full stack
+ * trace, and the crash [nowMillis]. Pure (no Android, no I/O) so it is unit
+ * tested. The leading marker doubles as the file's sanity check in
+ * [CrashReporter.pendingReport].
+ */
+fun buildCrashReport(ctx: CrashContext, throwable: Throwable, nowMillis: Long): String {
+    val trace = StringWriter().also { throwable.printStackTrace(PrintWriter(it)) }.toString().trim()
+    val time = runCatching {
+        Instant.ofEpochMilli(nowMillis).atZone(ZoneId.systemDefault()).format(TIME_FORMAT)
+    }.getOrDefault(nowMillis.toString())
+    return buildString {
+        appendLine("Calendula crash report")
+        appendLine("App version: ${ctx.appVersionName} (${ctx.appVersionCode})")
+        appendLine("Android: ${ctx.androidRelease} (API ${ctx.sdkInt})")
+        appendLine("Device: ${ctx.manufacturer} ${ctx.model}")
+        appendLine("Locale: ${ctx.locale}")
+        appendLine("Time: $time")
+        appendLine()
+        appendLine("Stack trace:")
+        append(trace)
+    }
+}
+
+private val TIME_FORMAT = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")

app/src/main/java/de/jeanlucmakiola/calendula/data/di/DataModule.kt

@@ -14,6 +14,12 @@ import de.jeanlucmakiola.calendula.data.calendar.AndroidCalendarDataSource
 import de.jeanlucmakiola.calendula.data.calendar.CalendarDataSource
 import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
 import de.jeanlucmakiola.calendula.data.calendar.CalendarRepositoryImpl
+import de.jeanlucmakiola.calendula.data.contacts.AndroidContactSpecialDatesDataSource
+import de.jeanlucmakiola.calendula.data.contacts.AndroidSpecialDatesCalendarSpec
+import de.jeanlucmakiola.calendula.data.contacts.ContactSpecialDatesDataSource
+import de.jeanlucmakiola.calendula.data.contacts.SpecialDatesCalendarSpec
+import de.jeanlucmakiola.calendula.data.reminders.AndroidReminderAlertStore
+import de.jeanlucmakiola.calendula.data.reminders.ReminderAlertStore
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.Dispatchers
 import javax.inject.Singleton
@@ -37,6 +43,24 @@ abstract class DataBindModule {
     abstract fun bindCalendarRepository(
         impl: CalendarRepositoryImpl,
     ): CalendarRepository
+
+    @Binds
+    @Singleton
+    abstract fun bindReminderAlertStore(
+        impl: AndroidReminderAlertStore,
+    ): ReminderAlertStore
+
+    @Binds
+    @Singleton
+    abstract fun bindContactSpecialDatesDataSource(
+        impl: AndroidContactSpecialDatesDataSource,
+    ): ContactSpecialDatesDataSource
+
+    @Binds
+    @Singleton
+    abstract fun bindSpecialDatesCalendarSpec(
+        impl: AndroidSpecialDatesCalendarSpec,
+    ): SpecialDatesCalendarSpec
 }
 
 @Module

app/src/main/java/de/jeanlucmakiola/calendula/data/fonts/CustomFontStore.kt

@@ -0,0 +1,57 @@
+package de.jeanlucmakiola.calendula.data.fonts
+
+import android.content.Context
+import android.net.Uri
+import de.jeanlucmakiola.calendula.domain.FontRole
+import java.io.File
+import java.util.Locale
+import android.graphics.fonts.Font as PlatformFont
+
+/**
+ * Storage for user-loaded custom fonts (issue #19). A font a user picks via the
+ * system file picker is copied into the app's private storage — one file per
+ * [FontRole] — so the selection survives even if the original is later moved or
+ * deleted, and never leaves the app. The chosen file is validated as a real font
+ * before it replaces the previous one, so a bad pick can't wedge the app-wide
+ * typography.
+ */
+object CustomFontStore {
+
+    private fun dir(context: Context): File = File(context.filesDir, "fonts")
+
+    /** The stored font file for [role] (may not exist yet). */
+    fun file(context: Context, role: FontRole): File =
+        File(dir(context), "${role.name.lowercase(Locale.ROOT)}.ttf")
+
+    fun exists(context: Context, role: FontRole): Boolean =
+        file(context, role).let { it.exists() && it.length() > 0 }
+
+    /**
+     * Copy [uri] into per-role storage, first validating that it parses as a
+     * font. Returns true on success; on any failure the previous file is left
+     * untouched and false is returned (the caller keeps the old selection).
+     */
+    fun import(context: Context, role: FontRole, uri: Uri): Boolean {
+        val target = file(context, role)
+        target.parentFile?.mkdirs()
+        val tmp = File(target.parentFile, "${role.name.lowercase(Locale.ROOT)}.tmp")
+        return try {
+            context.contentResolver.openInputStream(uri)?.use { input ->
+                tmp.outputStream().use { output -> input.copyTo(output) }
+            } ?: return false
+            // Font.Builder throws IOException for anything that isn't a valid
+            // font file (API 29+, which is our minSdk) — a cheap, reliable check.
+            PlatformFont.Builder(tmp).build()
+            if (target.exists() && !target.delete()) return false
+            tmp.renameTo(target)
+        } catch (_: Exception) {
+            tmp.delete()
+            false
+        }
+    }
+
+    /** Forget the custom font for [role] (used when switching away from it). */
+    fun clear(context: Context, role: FontRole) {
+        file(context, role).delete()
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/ics/IcsExporter.kt

@@ -0,0 +1,78 @@
+package de.jeanlucmakiola.calendula.data.ics
+
+import android.content.Context
+import android.net.Uri
+import androidx.core.content.FileProvider
+import androidx.documentfile.provider.DocumentFile
+import dagger.hilt.android.qualifiers.ApplicationContext
+import java.io.File
+import java.io.IOException
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * The Android IO edge of `.ics` export: writes a serialised calendar to a
+ * SAF document (whole-calendar backup) or stages it in a cache file behind a
+ * `FileProvider` content Uri (single-event share). The serialisation itself is
+ * the pure `domain.ics.IcsWriter`; this class only moves bytes.
+ */
+@Singleton
+class IcsExporter @Inject constructor(
+    @ApplicationContext private val context: Context,
+) {
+
+    /** Write [content] to the SAF document at [uri] as UTF-8. Throws on failure. */
+    fun writeDocument(uri: Uri, content: String) {
+        context.contentResolver.openOutputStream(uri)?.use { out ->
+            out.write(content.toByteArray(Charsets.UTF_8))
+            // Only the scheme — the full Uri can embed the user's chosen filename.
+        } ?: throw IOException("Could not open output stream for export (scheme=${uri.scheme})")
+    }
+
+    /**
+     * Write [content] to [fileName] inside the persisted SAF tree [folder],
+     * overwriting it if it already exists (the automatic-backup destination).
+     * Requires a persisted write grant on [folder]. Throws on failure.
+     */
+    fun writeToFolder(folder: Uri, fileName: String, content: String) {
+        val dir = DocumentFile.fromTreeUri(context, folder)
+            ?: throw IOException("Backup folder is not accessible")
+        if (!dir.exists() || !dir.canWrite()) {
+            throw IOException("Backup folder is missing or not writable")
+        }
+        // Reuse the canonical file if present and clean up any "name (1).ics"
+        // duplicates SAF may have created if two runs ever raced — so we always
+        // converge on a single overwritten file.
+        val base = fileName.substringBeforeLast('.')
+        val ext = fileName.substringAfterLast('.', "")
+        var target: DocumentFile? = null
+        for (child in dir.listFiles()) {
+            val name = child.name ?: continue
+            when {
+                name == fileName -> target = child
+                name.startsWith("$base (") && name.endsWith(".$ext") -> child.delete()
+            }
+        }
+        val file = target
+            ?: dir.createFile(MIME_CALENDAR, fileName)
+            ?: throw IOException("Could not create backup file in the chosen folder")
+        writeDocument(file.uri, content)
+    }
+
+    /**
+     * Stage [content] in a private cache file and return a shareable content
+     * Uri for an `ACTION_SEND`. [fileName] is the suggested `.ics` name shown to
+     * the receiving app. The authority mirrors the manifest's `FileProvider`.
+     */
+    fun stageShareFile(fileName: String, content: String): Uri {
+        val dir = File(context.cacheDir, SHARE_DIR).apply { mkdirs() }
+        val file = File(dir, fileName)
+        file.writeText(content, Charsets.UTF_8)
+        return FileProvider.getUriForFile(context, "${context.packageName}.fileprovider", file)
+    }
+
+    private companion object {
+        const val SHARE_DIR = "shared_ics"
+        const val MIME_CALENDAR = "text/calendar"
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/ics/IcsImporter.kt

@@ -0,0 +1,21 @@
+package de.jeanlucmakiola.calendula.data.ics
+
+import android.content.Context
+import android.net.Uri
+import dagger.hilt.android.qualifiers.ApplicationContext
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Android IO edge of `.ics` import: reads the text of a received/opened
+ * document [Uri]. Parsing is the pure `domain.ics.IcsParser`; this class only
+ * pulls bytes off the ContentResolver. Returns null on any read failure.
+ */
+@Singleton
+class IcsImporter @Inject constructor(
+    @ApplicationContext private val context: Context,
+) {
+    fun readText(uri: Uri): String? = runCatching {
+        context.contentResolver.openInputStream(uri)?.use { it.readBytes().toString(Charsets.UTF_8) }
+    }.getOrNull()
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/prefs/CalendarPrefs.kt

@@ -3,6 +3,7 @@ package de.jeanlucmakiola.calendula.data.prefs
 import androidx.datastore.core.DataStore
 import androidx.datastore.preferences.core.Preferences
 import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.core.longPreferencesKey
 import androidx.datastore.preferences.core.stringPreferencesKey
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.map
@@ -38,7 +39,46 @@ class CalendarPrefs @Inject constructor(
         }
     }
 
+    /**
+     * App-side preference for "calendars the user has disabled in this app" — a
+     * heavier level than [hiddenCalendarIds]. A disabled calendar is removed from
+     * every surface (drawer filter, event-form picker, import picker) and its
+     * events never appear; it stays listed only in Settings → Calendars so it can
+     * be re-enabled. Stored exactly like the hidden set; never touches the
+     * system's VISIBLE/SYNC_EVENTS flags, so other calendar apps are unaffected.
+     */
+    val disabledCalendarIds: Flow<Set<Long>> = store.data.map { prefs ->
+        prefs[DISABLED_IDS_KEY].orEmpty()
+            .split(',')
+            .mapNotNull { it.trim().toLongOrNull() }
+            .toSet()
+    }
+
+    suspend fun setDisabledCalendarIds(ids: Set<Long>) {
+        store.edit { prefs ->
+            if (ids.isEmpty()) {
+                prefs.remove(DISABLED_IDS_KEY)
+            } else {
+                prefs[DISABLED_IDS_KEY] = ids.sorted().joinToString(",")
+            }
+        }
+    }
+
+    /**
+     * The calendar the user last created an event in; preselected in the
+     * event form. Null until the first event is created.
+     */
+    val lastUsedCalendarId: Flow<Long?> = store.data.map { prefs ->
+        prefs[LAST_USED_CALENDAR_KEY]
+    }
+
+    suspend fun setLastUsedCalendarId(id: Long) {
+        store.edit { prefs -> prefs[LAST_USED_CALENDAR_KEY] = id }
+    }
+
     companion object {
         internal val HIDDEN_IDS_KEY = stringPreferencesKey("hidden_calendar_ids")
+        internal val DISABLED_IDS_KEY = stringPreferencesKey("disabled_calendar_ids")
+        internal val LAST_USED_CALENDAR_KEY = longPreferencesKey("last_used_calendar_id")
     }
 }

app/src/main/java/de/jeanlucmakiola/calendula/data/prefs/SettingsPrefs.kt

@@ -0,0 +1,853 @@
+package de.jeanlucmakiola.calendula.data.prefs
+
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.core.booleanPreferencesKey
+import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.core.intPreferencesKey
+import androidx.datastore.preferences.core.longPreferencesKey
+import androidx.datastore.preferences.core.stringPreferencesKey
+import de.jeanlucmakiola.calendula.domain.EventFormField
+import de.jeanlucmakiola.calendula.domain.FontRole
+import de.jeanlucmakiola.calendula.domain.contacts.SpecialDateType
+import de.jeanlucmakiola.calendula.ui.agenda.AgendaRange
+import de.jeanlucmakiola.calendula.ui.agenda.parseAgendaRange
+import de.jeanlucmakiola.calendula.ui.agenda.storageValue
+import de.jeanlucmakiola.calendula.ui.common.CalendarView
+import de.jeanlucmakiola.calendula.ui.common.IMPLEMENTED_VIEWS
+import de.jeanlucmakiola.calendula.ui.common.QuickSwitchConfig
+import de.jeanlucmakiola.calendula.ui.theme.FONT_SYSTEM_TOKEN
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.map
+import kotlinx.datetime.DayOfWeek
+import java.time.temporal.WeekFields
+import java.util.Locale
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/** Light/dark override. SYSTEM follows the device setting. */
+enum class ThemeMode { SYSTEM, LIGHT, DARK }
+
+/**
+ * Week-start override. [Auto] derives the first day from the active locale;
+ * [Day] pins a specific weekday (any of the seven).
+ */
+sealed interface WeekStartPref {
+    data object Auto : WeekStartPref
+    data class Day(val day: DayOfWeek) : WeekStartPref
+}
+
+/**
+ * Clock convention for time-of-day labels. AUTO follows the device's 24-hour
+ * system setting; the others force a 12- or 24-hour clock app-wide.
+ */
+enum class TimeFormatPref { AUTO, TWELVE_HOUR, TWENTY_FOUR_HOUR }
+
+/**
+ * How the Agenda screen treats events that have already finished today: [SHOW]
+ * leaves them as-is (the historical behaviour), [DIM] fades them, [HIDE] drops
+ * them from the list entirely.
+ */
+enum class PastEventDisplay { SHOW, DIM, HIDE }
+
+/** Parse a stored [PastEventDisplay.name]; unknown/null falls back to [default]. */
+fun parsePastEventDisplay(
+    stored: String?,
+    default: PastEventDisplay = PastEventDisplay.SHOW,
+): PastEventDisplay = PastEventDisplay.entries.firstOrNull { it.name == stored } ?: default
+
+/**
+ * Resolve to a concrete 24-hour flag. AUTO defers to [systemIs24Hour] (the
+ * device's `DateFormat.is24HourFormat` value).
+ */
+fun TimeFormatPref.is24Hour(systemIs24Hour: Boolean): Boolean = when (this) {
+    TimeFormatPref.AUTO -> systemIs24Hour
+    TimeFormatPref.TWELVE_HOUR -> false
+    TimeFormatPref.TWENTY_FOUR_HOUR -> true
+}
+
+/**
+ * Resolve the preference to a concrete first-day-of-week. [WeekStartPref.Auto]
+ * reads the locale's convention (e.g. Monday in DE, Sunday in en-US).
+ */
+fun WeekStartPref.resolveFirstDay(locale: Locale): DayOfWeek = when (this) {
+    is WeekStartPref.Day -> day
+    // java.time.DayOfWeek.value is ISO 1..7 (Mon..Sun) — same numbering kotlinx uses.
+    WeekStartPref.Auto -> DayOfWeek(WeekFields.of(locale).firstDayOfWeek.value)
+}
+
+/**
+ * Display settings (M4) persisted app-side: theme override, Material You
+ * dynamic colour, and week start. Language is handled separately through
+ * AppCompatDelegate (which persists its own per-app locale).
+ *
+ * Enum prefs round-trip by [Enum.name]; an unknown/garbage stored value falls
+ * back to the default rather than throwing (see SettingsPrefsTest).
+ */
+@Singleton
+class SettingsPrefs @Inject constructor(
+    private val store: DataStore<Preferences>,
+) {
+
+    val themeMode: Flow<ThemeMode> = store.data.map { prefs ->
+        prefs[THEME_MODE_KEY].toEnum(ThemeMode.SYSTEM)
+    }
+
+    val dynamicColor: Flow<Boolean> = store.data.map { prefs ->
+        prefs[DYNAMIC_COLOR_KEY] ?: true
+    }
+
+    val weekStart: Flow<WeekStartPref> = store.data.map { prefs ->
+        parseWeekStart(prefs[WEEK_START_KEY])
+    }
+
+    suspend fun setThemeMode(mode: ThemeMode) {
+        store.edit { it[THEME_MODE_KEY] = mode.name }
+    }
+
+    suspend fun setDynamicColor(enabled: Boolean) {
+        store.edit { it[DYNAMIC_COLOR_KEY] = enabled }
+    }
+
+    /**
+     * Custom-font tokens per Material typeface role (issue #19). Stored as opaque
+     * strings — "system", "custom", or a bundled font's token — resolved to a
+     * FontFamily at the theme layer; an unknown token degrades to the default.
+     */
+    val brandFont: Flow<String> = store.data.map { prefs ->
+        prefs[BRAND_FONT_KEY] ?: FONT_SYSTEM_TOKEN
+    }
+
+    val plainFont: Flow<String> = store.data.map { prefs ->
+        prefs[PLAIN_FONT_KEY] ?: FONT_SYSTEM_TOKEN
+    }
+
+    suspend fun setBrandFont(token: String) {
+        store.edit { it[BRAND_FONT_KEY] = token }
+    }
+
+    suspend fun setPlainFont(token: String) {
+        store.edit { it[PLAIN_FONT_KEY] = token }
+    }
+
+    /**
+     * A per-role bump counter for the user-loaded custom font. Re-importing
+     * overwrites the same file under the same "custom" token, so the token alone
+     * can't signal the change; this stamp — carried into AppFontSettings — breaks
+     * value equality so the resolved FontFamily (and its previews) refresh. A
+     * missing key is 0 (existing installs); the first import bumps it to 1.
+     */
+    val brandFontStamp: Flow<Int> = store.data.map { prefs -> prefs[BRAND_FONT_STAMP_KEY] ?: 0 }
+
+    val plainFontStamp: Flow<Int> = store.data.map { prefs -> prefs[PLAIN_FONT_STAMP_KEY] ?: 0 }
+
+    /** Bump [role]'s custom-font stamp after a re-import so equality-keyed caches refresh. */
+    suspend fun bumpCustomFontStamp(role: FontRole) {
+        val key = when (role) {
+            FontRole.BRAND -> BRAND_FONT_STAMP_KEY
+            FontRole.PLAIN -> PLAIN_FONT_STAMP_KEY
+        }
+        store.edit { it[key] = (it[key] ?: 0) + 1 }
+    }
+
+    suspend fun setWeekStart(pref: WeekStartPref) {
+        store.edit { it[WEEK_START_KEY] = pref.storageValue() }
+    }
+
+    /** Clock convention for time-of-day labels (v2.11). Defaults to AUTO (system). */
+    val timeFormat: Flow<TimeFormatPref> = store.data.map { prefs ->
+        prefs[TIME_FORMAT_KEY].toEnum(TimeFormatPref.AUTO)
+    }
+
+    suspend fun setTimeFormat(pref: TimeFormatPref) {
+        store.edit { it[TIME_FORMAT_KEY] = pref.name }
+    }
+
+    /**
+     * Whether the week/day timeline draws a faint separator line at each hour
+     * (v2.11). Defaults to OFF — the historical clean look; users opt in.
+     */
+    val showHourLines: Flow<Boolean> = store.data.map { prefs ->
+        prefs[SHOW_HOUR_LINES_KEY] ?: false
+    }
+
+    suspend fun setShowHourLines(enabled: Boolean) {
+        store.edit { it[SHOW_HOUR_LINES_KEY] = enabled }
+    }
+
+    /**
+     * How the Agenda screen treats events that already ended today. Defaults to
+     * [PastEventDisplay.SHOW] — the historical behaviour; users opt into dimming
+     * or hiding.
+     */
+    val pastEventDisplay: Flow<PastEventDisplay> = store.data.map { prefs ->
+        prefs[PAST_EVENT_DISPLAY_KEY].toEnum(PastEventDisplay.SHOW)
+    }
+
+    suspend fun setPastEventDisplay(mode: PastEventDisplay) {
+        store.edit { it[PAST_EVENT_DISPLAY_KEY] = mode.name }
+    }
+
+    /**
+     * Whether the month/week grids fade events that have already finished.
+     * Defaults to OFF — independent of the Agenda's [pastEventDisplay].
+     */
+    val dimCompletedEvents: Flow<Boolean> = store.data.map { prefs ->
+        prefs[DIM_COMPLETED_EVENTS_KEY] ?: false
+    }
+
+    suspend fun setDimCompletedEvents(enabled: Boolean) {
+        store.edit { it[DIM_COMPLETED_EVENTS_KEY] = enabled }
+    }
+
+    /**
+     * How far ahead the in-app Agenda screen shows events (v2.11). Defaults to
+     * [AgendaRange.Month] — a month of upcoming events. Independent of the
+     * widget's [agendaWidgetRange].
+     */
+    val agendaScreenRange: Flow<AgendaRange> = store.data.map { prefs ->
+        parseAgendaRange(prefs[AGENDA_SCREEN_RANGE_KEY], AgendaRange.Month)
+    }
+
+    suspend fun setAgendaScreenRange(range: AgendaRange) {
+        store.edit { it[AGENDA_SCREEN_RANGE_KEY] = range.storageValue() }
+    }
+
+    /** How far ahead the agenda **widget** shows events (v2.11). Defaults to Month. */
+    val agendaWidgetRange: Flow<AgendaRange> = store.data.map { prefs ->
+        parseAgendaRange(prefs[AGENDA_WIDGET_RANGE_KEY], AgendaRange.Month)
+    }
+
+    suspend fun setAgendaWidgetRange(range: AgendaRange) {
+        store.edit { it[AGENDA_WIDGET_RANGE_KEY] = range.storageValue() }
+    }
+
+    /**
+     * Whether the agenda shows its top range bar — the "showing …" header and
+     * the session range switcher (v2.11). Default ON.
+     */
+    val agendaShowRangeBar: Flow<Boolean> = store.data.map { prefs ->
+        prefs[AGENDA_SHOW_RANGE_BAR_KEY] ?: true
+    }
+
+    suspend fun setAgendaShowRangeBar(enabled: Boolean) {
+        store.edit { it[AGENDA_SHOW_RANGE_BAR_KEY] = enabled }
+    }
+
+    /**
+     * The calendar view the app opens on (M1). Defaults to [CalendarView.Week] —
+     * the historical hard-coded startup view — so existing users see no change
+     * until they pick another. Also the bottom of the in-app view back stack, so
+     * back from any other view returns here before exiting.
+     */
+    val defaultView: Flow<CalendarView> = store.data.map { prefs ->
+        prefs[DEFAULT_VIEW_KEY].toEnum(CalendarView.Week)
+    }
+
+    suspend fun setDefaultView(view: CalendarView) {
+        store.edit { it[DEFAULT_VIEW_KEY] = view.name }
+    }
+
+    /**
+     * Quick-switch button customisation (#24): the ordered full view list plus
+     * which views are enabled in the cycle. Stored comma-joined by enum name, a
+     * "!" prefix marking a disabled view (e.g. "Month,Week,!Day,Agenda"). Missing
+     * views are appended enabled and unknown names dropped, so a future view
+     * defaults into the cycle. An absent key means [QuickSwitchConfig.Default].
+     */
+    val quickSwitchConfig: Flow<QuickSwitchConfig> = store.data.map { prefs ->
+        parseQuickSwitch(prefs[QUICK_SWITCH_VIEWS_KEY])
+    }
+
+    suspend fun setQuickSwitchConfig(config: QuickSwitchConfig) {
+        store.edit { it[QUICK_SWITCH_VIEWS_KEY] = serializeQuickSwitch(config) }
+    }
+
+    /**
+     * Atomic read-modify-write of the quick-switch config: [transform] sees the
+     * value currently stored, parsed inside the edit block, not the async-echoed
+     * UI snapshot. Two rapid intents (a toggle then a drag) therefore compose
+     * instead of each re-serialising a stale copy of the other field over it.
+     */
+    suspend fun updateQuickSwitch(transform: (QuickSwitchConfig) -> QuickSwitchConfig) {
+        store.edit { prefs ->
+            val current = parseQuickSwitch(prefs[QUICK_SWITCH_VIEWS_KEY])
+            prefs[QUICK_SWITCH_VIEWS_KEY] = serializeQuickSwitch(transform(current))
+        }
+    }
+
+    /**
+     * Navigation-drawer view order (#24). Comma-joined enum names; missing views
+     * are appended in default order and unknown names dropped. Absent key means
+     * [IMPLEMENTED_VIEWS] (the historical fixed order).
+     */
+    val drawerViewOrder: Flow<List<CalendarView>> = store.data.map { prefs ->
+        parseViewOrder(prefs[DRAWER_VIEW_ORDER_KEY])
+    }
+
+    suspend fun setDrawerViewOrder(order: List<CalendarView>) {
+        store.edit { it[DRAWER_VIEW_ORDER_KEY] = order.joinToString(",") { view -> view.name } }
+    }
+
+    /**
+     * Optional event-form fields shown by default (the rest hide behind
+     * "more fields"). Stored comma-joined by enum name: an absent key means
+     * the factory default, an empty string means "none". Unknown names are
+     * dropped defensively, like the other enum prefs.
+     */
+    val defaultFormFields: Flow<Set<EventFormField>> = store.data.map { prefs ->
+        parseFormFields(prefs[FORM_FIELDS_KEY])
+    }
+
+    suspend fun setFormFieldDefault(field: EventFormField, enabled: Boolean) {
+        store.edit { prefs ->
+            val current = parseFormFields(prefs[FORM_FIELDS_KEY])
+            val updated = if (enabled) current + field else current - field
+            prefs[FORM_FIELDS_KEY] = updated.joinToString(",") { it.name }
+        }
+    }
+
+    /**
+     * Whether opening the new-event form focuses the title field and raises the
+     * keyboard straight away (issue #10). Default ON — a new event almost always
+     * gets a title, so this saves a tap; users who set the time/calendar first
+     * can turn it off. Only the create form auto-focuses — editing never does.
+     */
+    val autofocusEventTitle: Flow<Boolean> = store.data.map { prefs ->
+        prefs[AUTOFOCUS_EVENT_TITLE_KEY] ?: true
+    }
+
+    suspend fun setAutofocusEventTitle(enabled: Boolean) {
+        store.edit { it[AUTOFOCUS_EVENT_TITLE_KEY] = enabled }
+    }
+
+    /**
+     * Whether Calendula posts reminder notifications (v1.4). Defaults to ON —
+     * for users whose only calendar app this is, reminders are essential; the
+     * onboarding step and Settings warn about duplicates from a second app.
+     */
+    val remindersEnabled: Flow<Boolean> = store.data.map { prefs ->
+        prefs[REMINDERS_ENABLED_KEY] ?: true
+    }
+
+    suspend fun setRemindersEnabled(enabled: Boolean) {
+        store.edit { it[REMINDERS_ENABLED_KEY] = enabled }
+    }
+
+    /**
+     * Whether to offer a custom event colour even on calendars that publish no
+     * colour palette (most local calendars handle it fine; synced calendars
+     * without a palette — some CalDAV — may drop or overwrite a raw colour on
+     * their next sync). Defaults to OFF: such calendars hide the colour picker
+     * until the user opts in, accepting the limitation. Local calendars and
+     * palette-backed calendars (Google, …) are unaffected by this flag.
+     */
+    val allowColorOnUnsupportedCalendars: Flow<Boolean> = store.data.map { prefs ->
+        prefs[ALLOW_COLOR_UNSUPPORTED_KEY] ?: false
+    }
+
+    suspend fun setAllowColorOnUnsupportedCalendars(enabled: Boolean) {
+        store.edit { it[ALLOW_COLOR_UNSUPPORTED_KEY] = enabled }
+    }
+
+    /**
+     * Whether the one-time reminder onboarding step (after the calendar
+     * grant) has been shown — also true for users who tapped "not now".
+     */
+    val reminderOnboardingDone: Flow<Boolean> = store.data.map { prefs ->
+        prefs[REMINDER_ONBOARDING_KEY] ?: false
+    }
+
+    suspend fun setReminderOnboardingDone() {
+        store.edit { it[REMINDER_ONBOARDING_KEY] = true }
+    }
+
+    /**
+     * The default reminder lead times (minutes before start) prefilled on new
+     * **timed** events. The empty list = no default reminder — the prior
+     * behaviour, kept as the factory default so existing users aren't surprised by
+     * reminders they never asked for. Stored as a comma-joined list of minutes, or
+     * "none"/empty for no reminder (also the unset state). A legacy single value
+     * ("30") parses transparently to a one-element list. Per-calendar overrides in
+     * [perCalendarReminderOverride] take precedence; all-day events instead use
+     * [defaultAllDayReminderMinutes]. Resolve with [resolveDefaultReminder].
+     */
+    val defaultReminderMinutes: Flow<List<Int>> = store.data.map { prefs ->
+        prefs[DEFAULT_REMINDER_KEY].toReminderList()
+    }
+
+    suspend fun setDefaultReminderMinutes(minutes: List<Int>) {
+        store.edit { it[DEFAULT_REMINDER_KEY] = minutes.toStoredReminders() }
+    }
+
+    /**
+     * The default reminder lead times prefilled on new **all-day** events, in
+     * minutes before the start of the day. All-day events want day-scale lead
+     * times ("1 day before"), so they have their own default rather than reusing
+     * the timed one. Empty list = no default. Per-calendar overrides do **not**
+     * apply to all-day events — they always use this global value.
+     */
+    val defaultAllDayReminderMinutes: Flow<List<Int>> = store.data.map { prefs ->
+        prefs[DEFAULT_ALLDAY_REMINDER_KEY].toReminderList()
+    }
+
+    suspend fun setDefaultAllDayReminderMinutes(minutes: List<Int>) {
+        store.edit { it[DEFAULT_ALLDAY_REMINDER_KEY] = minutes.toStoredReminders() }
+    }
+
+    /**
+     * Wall-clock time, as minutes from local midnight, at which **all-day**
+     * reminders fire. All-day events live at UTC midnight, so a raw "1 day
+     * before" would fire at an off hour (02:00 local in CEST); this time is
+     * encoded into the provider offset so the reminder lands at, e.g., 09:00 the
+     * day before instead. Global for every all-day reminder; default 09:00.
+     * Stored/clamped to a valid 0..1439 minute-of-day.
+     */
+    val allDayReminderTimeMinutes: Flow<Int> = store.data.map { prefs ->
+        (prefs[ALLDAY_REMINDER_TIME_KEY] ?: DEFAULT_ALLDAY_REMINDER_TIME)
+            .coerceIn(0, MINUTES_PER_DAY - 1)
+    }
+
+    suspend fun setAllDayReminderTimeMinutes(minutesOfDay: Int) {
+        store.edit { it[ALLDAY_REMINDER_TIME_KEY] = minutesOfDay.coerceIn(0, MINUTES_PER_DAY - 1) }
+    }
+
+    /**
+     * How long the notification "Snooze" action defers a reminder, in minutes.
+     * Tapping Snooze cancels the notification and re-posts it after this delay
+     * via an exact alarm (the calendar provider won't re-fire). Default 10 min;
+     * clamped to at least 1.
+     */
+    val snoozeMinutes: Flow<Int> = store.data.map { prefs ->
+        (prefs[SNOOZE_MINUTES_KEY] ?: DEFAULT_SNOOZE_MINUTES).coerceAtLeast(1)
+    }
+
+    suspend fun setSnoozeMinutes(minutes: Int) {
+        store.edit { it[SNOOZE_MINUTES_KEY] = minutes.coerceAtLeast(1) }
+    }
+
+    /**
+     * Per-calendar overrides of [defaultReminderMinutes] for **timed** events,
+     * keyed by calendar id. A calendar **present** in the map overrides the global
+     * timed default for its new events: an **empty** list means "no reminder", a
+     * non-empty list means those lead times. A calendar **absent** from the map
+     * inherits the global default. Serialised as `id=value;id=value`, where a value
+     * is a comma-joined minute list or `none` for an explicit no-reminder override.
+     * (All-day events ignore this and use [defaultAllDayReminderMinutes].)
+     */
+    val perCalendarReminderOverride: Flow<Map<Long, List<Int>>> = store.data.map { prefs ->
+        parseReminderOverrides(prefs[CALENDAR_REMINDER_OVERRIDE_KEY])
+    }
+
+    suspend fun setCalendarReminderOverride(calendarId: Long, override: CalendarReminderOverride) {
+        store.edit { prefs ->
+            val current = parseReminderOverrides(prefs[CALENDAR_REMINDER_OVERRIDE_KEY]).toMutableMap()
+            current.applyOverride(calendarId, override)
+            prefs[CALENDAR_REMINDER_OVERRIDE_KEY] = serializeReminderOverrides(current)
+        }
+    }
+
+    /**
+     * Per-calendar overrides of [defaultAllDayReminderMinutes] for **all-day**
+     * events, with the same semantics as [perCalendarReminderOverride] (absent =
+     * inherit the global all-day default; present null = no reminder).
+     */
+    val perCalendarAllDayReminderOverride: Flow<Map<Long, List<Int>>> = store.data.map { prefs ->
+        parseReminderOverrides(prefs[CALENDAR_ALLDAY_REMINDER_OVERRIDE_KEY])
+    }
+
+    suspend fun setCalendarAllDayReminderOverride(
+        calendarId: Long,
+        override: CalendarReminderOverride,
+    ) {
+        store.edit { prefs ->
+            val current =
+                parseReminderOverrides(prefs[CALENDAR_ALLDAY_REMINDER_OVERRIDE_KEY]).toMutableMap()
+            current.applyOverride(calendarId, override)
+            prefs[CALENDAR_ALLDAY_REMINDER_OVERRIDE_KEY] = serializeReminderOverrides(current)
+        }
+    }
+
+    // --- Automatic backup (issue #8) ------------------------------------
+
+    /** Whether periodic automatic `.ics` export of local calendars is on. Default OFF. */
+    val autoBackupEnabled: Flow<Boolean> = store.data.map { it[AUTO_BACKUP_ENABLED_KEY] ?: false }
+
+    suspend fun setAutoBackupEnabled(enabled: Boolean) {
+        store.edit { it[AUTO_BACKUP_ENABLED_KEY] = enabled }
+    }
+
+    /** Export interval in minutes. Default daily; floored at [MIN_BACKUP_INTERVAL]. */
+    val autoBackupIntervalMinutes: Flow<Long> = store.data.map { prefs ->
+        (prefs[AUTO_BACKUP_INTERVAL_KEY] ?: DEFAULT_BACKUP_INTERVAL).coerceAtLeast(MIN_BACKUP_INTERVAL)
+    }
+
+    suspend fun setAutoBackupIntervalMinutes(minutes: Long) {
+        store.edit { it[AUTO_BACKUP_INTERVAL_KEY] = minutes.coerceAtLeast(MIN_BACKUP_INTERVAL) }
+    }
+
+    /** Persisted SAF tree Uri of the destination folder, or null if unset. */
+    val autoBackupFolderUri: Flow<String?> = store.data.map { it[AUTO_BACKUP_FOLDER_KEY] }
+
+    suspend fun setAutoBackupFolderUri(uri: String?) {
+        store.edit { prefs ->
+            if (uri == null) prefs.remove(AUTO_BACKUP_FOLDER_KEY) else prefs[AUTO_BACKUP_FOLDER_KEY] = uri
+        }
+    }
+
+    /** Outcome of the last automatic run, for the settings status line. */
+    val autoBackupStatus: Flow<BackupStatus> = store.data.map { prefs ->
+        BackupStatus(
+            lastRun = prefs[AUTO_BACKUP_LAST_RUN_KEY] ?: 0L,
+            lastSuccess = prefs[AUTO_BACKUP_LAST_SUCCESS_KEY] ?: true,
+            consecutiveFailures = prefs[AUTO_BACKUP_FAILURES_KEY] ?: 0,
+        )
+    }
+
+    /** Record an automatic run's outcome; resets the failure streak on success. */
+    suspend fun recordAutoBackupRun(success: Boolean, atMillis: Long) {
+        store.edit { prefs ->
+            prefs[AUTO_BACKUP_LAST_RUN_KEY] = atMillis
+            prefs[AUTO_BACKUP_LAST_SUCCESS_KEY] = success
+            val failures = prefs[AUTO_BACKUP_FAILURES_KEY] ?: 0
+            prefs[AUTO_BACKUP_FAILURES_KEY] = if (success) 0 else failures + 1
+        }
+    }
+
+    // --- Contact special dates (issue #15) ------------------------------
+
+    /** Master switch for the contact special-dates mirror. Default OFF (opt-in). */
+    val specialDatesEnabled: Flow<Boolean> = store.data.map { it[SPECIAL_DATES_ENABLED_KEY] ?: false }
+
+    suspend fun setSpecialDatesEnabled(enabled: Boolean) {
+        store.edit { it[SPECIAL_DATES_ENABLED_KEY] = enabled }
+    }
+
+    /** The date types the user wants mirrored (default: all three). */
+    val specialDatesTypes: Flow<Set<SpecialDateType>> = store.data.map { prefs ->
+        SpecialDateType.entries.filterTo(mutableSetOf()) { prefs[typeEnabledKey(it)] ?: true }
+    }
+
+    suspend fun setSpecialDateTypeEnabled(type: SpecialDateType, enabled: Boolean) {
+        store.edit { it[typeEnabledKey(type)] = enabled }
+    }
+
+    /** The managed calendar id per type, for the ones that currently exist. */
+    val specialDatesCalendars: Flow<Map<SpecialDateType, Long>> = store.data.map { prefs ->
+        SpecialDateType.entries.mapNotNull { type ->
+            prefs[calendarIdKey(type)]?.let { type to it }
+        }.toMap()
+    }
+
+    /** Every managed calendar id — the editor locks title/date/recurrence for their events. */
+    val managedCalendarIds: Flow<Set<Long>> = specialDatesCalendars.map { it.values.toSet() }
+
+    suspend fun setSpecialDatesCalendarId(type: SpecialDateType, calendarId: Long?) {
+        store.edit { prefs ->
+            if (calendarId == null) prefs.remove(calendarIdKey(type)) else prefs[calendarIdKey(type)] = calendarId
+        }
+    }
+
+    /**
+     * The title template per type ("{name}'s birthday"); an empty string means
+     * unset, so the settings screen can seed the localized default. `{name}` is
+     * the contact name, `{age}` the age at the upcoming date (empty when the
+     * birth year is unknown or [specialDatesShowAge] is off).
+     */
+    val specialDatesTitleTemplates: Flow<Map<SpecialDateType, String>> = store.data.map { prefs ->
+        SpecialDateType.entries.associateWith { prefs[titleTemplateKey(it)].orEmpty() }
+    }
+
+    suspend fun setSpecialDatesTitleTemplate(type: SpecialDateType, template: String) {
+        store.edit { it[titleTemplateKey(type)] = template }
+    }
+
+    /** Whether `{year}` resolves in the title (only meaningful when the year is known). Default ON. */
+    val specialDatesShowYear: Flow<Boolean> = store.data.map { it[SPECIAL_DATES_SHOW_YEAR_KEY] ?: true }
+
+    suspend fun setSpecialDatesShowYear(enabled: Boolean) {
+        store.edit { it[SPECIAL_DATES_SHOW_YEAR_KEY] = enabled }
+    }
+
+    /** Outcome of the last mirror sync, for the settings status line. */
+    val specialDatesStatus: Flow<SpecialDatesStatus> = store.data.map { prefs ->
+        SpecialDatesStatus(
+            lastRun = prefs[SPECIAL_DATES_LAST_RUN_KEY] ?: 0L,
+            stalled = prefs[SPECIAL_DATES_STALLED_KEY]
+                ?.let { name -> SpecialDatesStalledReason.entries.firstOrNull { it.name == name } },
+        )
+    }
+
+    /** Record a sync outcome; [stalled] non-null marks the feature paused (e.g. permission revoked). */
+    suspend fun recordSpecialDatesRun(atMillis: Long, stalled: SpecialDatesStalledReason?) {
+        store.edit { prefs ->
+            prefs[SPECIAL_DATES_LAST_RUN_KEY] = atMillis
+            if (stalled == null) prefs.remove(SPECIAL_DATES_STALLED_KEY) else prefs[SPECIAL_DATES_STALLED_KEY] = stalled.name
+        }
+    }
+
+    /** Epoch millis of the last foreground-triggered sync, to debounce ON_RESUME. */
+    val specialDatesLastForegroundSync: Flow<Long> =
+        store.data.map { it[SPECIAL_DATES_LAST_FG_SYNC_KEY] ?: 0L }
+
+    suspend fun setSpecialDatesLastForegroundSync(atMillis: Long) {
+        store.edit { it[SPECIAL_DATES_LAST_FG_SYNC_KEY] = atMillis }
+    }
+
+    private fun typeEnabledKey(type: SpecialDateType) =
+        booleanPreferencesKey("special_dates_type_${type.name}")
+
+    private fun calendarIdKey(type: SpecialDateType) =
+        longPreferencesKey("special_dates_calendar_${type.name}")
+
+    private fun titleTemplateKey(type: SpecialDateType) =
+        stringPreferencesKey("special_dates_title_${type.name}")
+
+    private fun parseFormFields(stored: String?): Set<EventFormField> = when (stored) {
+        null -> DEFAULT_FORM_FIELDS
+        else -> stored.split(',')
+            .mapNotNull { name -> EventFormField.entries.firstOrNull { it.name == name.trim() } }
+            .toSet()
+    }
+
+    /** Parse a plain comma-joined view order, completed to every implemented view. */
+    private fun parseViewOrder(stored: String?): List<CalendarView> =
+        completeViewOrder(
+            stored?.split(',').orEmpty()
+                .mapNotNull { name -> CalendarView.entries.firstOrNull { it.name == name.trim() } },
+        )
+
+    /** Parse the quick-switch config; "!"-prefixed names are disabled. */
+    private fun parseQuickSwitch(stored: String?): QuickSwitchConfig {
+        if (stored == null) return QuickSwitchConfig.Default
+        val parsed = stored.split(',').mapNotNull { raw ->
+            val token = raw.trim()
+            val disabled = token.startsWith("!")
+            val name = if (disabled) token.drop(1) else token
+            CalendarView.entries.firstOrNull { it.name == name }?.let { it to disabled }
+        }
+        val order = completeViewOrder(parsed.map { it.first })
+        // Only views explicitly stored disabled are excluded; anything appended
+        // (a view added in a later release) defaults into the cycle.
+        val disabled = parsed.filter { it.second }.map { it.first }.toSet()
+        return QuickSwitchConfig(order, order.filterNot { it in disabled }.toSet())
+    }
+
+    private fun serializeQuickSwitch(config: QuickSwitchConfig): String =
+        completeViewOrder(config.order).joinToString(",") { view ->
+            if (view in config.enabled) view.name else "!${view.name}"
+        }
+
+    /** Keep the given order (de-duplicated), then append any views it omits. */
+    private fun completeViewOrder(seen: List<CalendarView>): List<CalendarView> {
+        val ordered = seen.distinct()
+        return ordered + IMPLEMENTED_VIEWS.filterNot { it in ordered }
+    }
+
+    companion object {
+        internal val THEME_MODE_KEY = stringPreferencesKey("theme_mode")
+        internal val DYNAMIC_COLOR_KEY = booleanPreferencesKey("dynamic_color")
+        internal val BRAND_FONT_KEY = stringPreferencesKey("brand_font")
+        internal val PLAIN_FONT_KEY = stringPreferencesKey("plain_font")
+        internal val BRAND_FONT_STAMP_KEY = intPreferencesKey("brand_font_stamp")
+        internal val PLAIN_FONT_STAMP_KEY = intPreferencesKey("plain_font_stamp")
+        internal val WEEK_START_KEY = stringPreferencesKey("week_start")
+        internal val AGENDA_SCREEN_RANGE_KEY = stringPreferencesKey("agenda_screen_range")
+        internal val AGENDA_WIDGET_RANGE_KEY = stringPreferencesKey("agenda_widget_range")
+        internal val AGENDA_SHOW_RANGE_BAR_KEY = booleanPreferencesKey("agenda_show_range_bar")
+        internal val TIME_FORMAT_KEY = stringPreferencesKey("time_format")
+        internal val SHOW_HOUR_LINES_KEY = booleanPreferencesKey("show_hour_lines")
+        internal val PAST_EVENT_DISPLAY_KEY = stringPreferencesKey("agenda_past_event_display")
+        internal val DIM_COMPLETED_EVENTS_KEY = booleanPreferencesKey("dim_completed_events")
+        internal val DEFAULT_VIEW_KEY = stringPreferencesKey("default_view")
+        internal val QUICK_SWITCH_VIEWS_KEY = stringPreferencesKey("quick_switch_views")
+        internal val DRAWER_VIEW_ORDER_KEY = stringPreferencesKey("drawer_view_order")
+        internal val FORM_FIELDS_KEY = stringPreferencesKey("event_form_default_fields")
+        internal val AUTOFOCUS_EVENT_TITLE_KEY = booleanPreferencesKey("autofocus_event_title")
+        internal val REMINDERS_ENABLED_KEY = booleanPreferencesKey("reminders_enabled")
+        internal val REMINDER_ONBOARDING_KEY = booleanPreferencesKey("reminder_onboarding_done")
+        internal val ALLOW_COLOR_UNSUPPORTED_KEY =
+            booleanPreferencesKey("allow_color_unsupported_calendars")
+        internal val DEFAULT_REMINDER_KEY = stringPreferencesKey("default_reminder_minutes")
+        internal val DEFAULT_ALLDAY_REMINDER_KEY =
+            stringPreferencesKey("default_allday_reminder_minutes")
+        internal val ALLDAY_REMINDER_TIME_KEY =
+            intPreferencesKey("allday_reminder_time_minutes")
+        /** 09:00 as minutes from midnight; the default all-day reminder fire time. */
+        internal const val DEFAULT_ALLDAY_REMINDER_TIME = 540
+        private const val MINUTES_PER_DAY = 1_440
+        internal val SNOOZE_MINUTES_KEY = intPreferencesKey("snooze_minutes")
+        /** Default snooze delay for the notification "Snooze" action. */
+        const val DEFAULT_SNOOZE_MINUTES = 10
+        internal val CALENDAR_REMINDER_OVERRIDE_KEY =
+            stringPreferencesKey("per_calendar_reminder_override")
+        internal val CALENDAR_ALLDAY_REMINDER_OVERRIDE_KEY =
+            stringPreferencesKey("per_calendar_allday_reminder_override")
+        internal val DEFAULT_FORM_FIELDS =
+            setOf(EventFormField.Location, EventFormField.Description)
+        internal val AUTO_BACKUP_ENABLED_KEY = booleanPreferencesKey("auto_backup_enabled")
+        internal val AUTO_BACKUP_INTERVAL_KEY = longPreferencesKey("auto_backup_interval_minutes")
+        internal val AUTO_BACKUP_FOLDER_KEY = stringPreferencesKey("auto_backup_folder_uri")
+        internal val AUTO_BACKUP_LAST_RUN_KEY = longPreferencesKey("auto_backup_last_run")
+        internal val AUTO_BACKUP_LAST_SUCCESS_KEY = booleanPreferencesKey("auto_backup_last_success")
+        internal val AUTO_BACKUP_FAILURES_KEY = intPreferencesKey("auto_backup_failures")
+        /** Default automatic-backup interval: daily. */
+        const val DEFAULT_BACKUP_INTERVAL = 1_440L
+        /** Floor for the automatic-backup interval (also above WorkManager's 15-min limit). */
+        const val MIN_BACKUP_INTERVAL = 30L
+
+        internal val SPECIAL_DATES_ENABLED_KEY = booleanPreferencesKey("special_dates_enabled")
+        internal val SPECIAL_DATES_SHOW_YEAR_KEY = booleanPreferencesKey("special_dates_show_year")
+        internal val SPECIAL_DATES_LAST_RUN_KEY = longPreferencesKey("special_dates_last_run")
+        internal val SPECIAL_DATES_STALLED_KEY = stringPreferencesKey("special_dates_stalled_reason")
+        internal val SPECIAL_DATES_LAST_FG_SYNC_KEY =
+            longPreferencesKey("special_dates_last_foreground_sync")
+    }
+}
+
+/** Snapshot of the special-dates mirror's last outcome (see [SettingsPrefs.specialDatesStatus]). */
+data class SpecialDatesStatus(
+    /** Epoch millis of the last sync, or 0 if it has never run. */
+    val lastRun: Long,
+    /** Non-null when the mirror is paused and why; null when healthy. */
+    val stalled: SpecialDatesStalledReason?,
+)
+
+/** Why the special-dates mirror is paused. */
+enum class SpecialDatesStalledReason {
+    /** READ_CONTACTS was revoked in system settings after the feature was enabled. */
+    PermissionRevoked,
+}
+
+/** Snapshot of the automatic backup's last outcome (see [SettingsPrefs.autoBackupStatus]). */
+data class BackupStatus(
+    /** Epoch millis of the last run, or 0 if it has never run. */
+    val lastRun: Long,
+    val lastSuccess: Boolean,
+    val consecutiveFailures: Int,
+)
+
+/** A calendar's reminder-default override (see [SettingsPrefs.perCalendarReminderOverride]). */
+sealed interface CalendarReminderOverride {
+    /** No override — the calendar uses the global default. */
+    data object Inherit : CalendarReminderOverride
+    /** Explicit "no reminder" for this calendar, regardless of the global default. */
+    data object None : CalendarReminderOverride
+    /** Specific lead times in minutes before the event start (non-empty). */
+    data class Minutes(val minutes: List<Int>) : CalendarReminderOverride
+}
+
+/**
+ * The stored override for [calendarId] in an override map, as a
+ * [CalendarReminderOverride] (absent → [CalendarReminderOverride.Inherit],
+ * empty → [CalendarReminderOverride.None]) — the inverse of how
+ * [SettingsPrefs.setCalendarReminderOverride] stores a choice.
+ */
+fun Map<Long, List<Int>>.choiceFor(calendarId: Long): CalendarReminderOverride = when {
+    !containsKey(calendarId) -> CalendarReminderOverride.Inherit
+    getValue(calendarId).isEmpty() -> CalendarReminderOverride.None
+    else -> CalendarReminderOverride.Minutes(getValue(calendarId))
+}
+
+/**
+ * The lead times to prefill on a new event: the matching per-calendar override
+ * if [calendarId] has one for this event kind, otherwise the global default for
+ * that kind. All-day events consult [allDayOverrides] / [allDayGlobal]; timed
+ * events consult [timedOverrides] / [timedGlobal]. The empty list = no reminder.
+ * Pure so it can be unit-tested.
+ */
+fun resolveDefaultReminder(
+    timedGlobal: List<Int>,
+    allDayGlobal: List<Int>,
+    timedOverrides: Map<Long, List<Int>>,
+    allDayOverrides: Map<Long, List<Int>>,
+    calendarId: Long?,
+    isAllDay: Boolean,
+): List<Int> {
+    val overrides = if (isAllDay) allDayOverrides else timedOverrides
+    val global = if (isAllDay) allDayGlobal else timedGlobal
+    return if (calendarId != null && overrides.containsKey(calendarId)) {
+        overrides.getValue(calendarId)
+    } else {
+        global
+    }
+}
+
+/**
+ * Apply a [CalendarReminderOverride] to an override map ([Inherit] removes the
+ * key; [None] and an empty [Minutes] both store the empty list).
+ */
+private fun MutableMap<Long, List<Int>>.applyOverride(
+    calendarId: Long,
+    override: CalendarReminderOverride,
+) {
+    when (override) {
+        CalendarReminderOverride.Inherit -> remove(calendarId)
+        CalendarReminderOverride.None -> put(calendarId, emptyList())
+        is CalendarReminderOverride.Minutes -> put(calendarId, override.minutes.normalizeReminders())
+    }
+}
+
+/** Sentinel stored for [WeekStartPref.Auto]; days store their [DayOfWeek.name]. */
+private const val WEEK_START_AUTO = "AUTO"
+
+private fun WeekStartPref.storageValue(): String = when (this) {
+    WeekStartPref.Auto -> WEEK_START_AUTO
+    is WeekStartPref.Day -> day.name
+}
+
+/**
+ * Parse the stored week-start value. "AUTO"/null/garbage → [WeekStartPref.Auto];
+ * a [DayOfWeek] name → [WeekStartPref.Day]. The legacy "MONDAY"/"SUNDAY" enum
+ * values migrate transparently, since both are valid day names.
+ */
+private fun parseWeekStart(stored: String?): WeekStartPref = when (stored) {
+    null, WEEK_START_AUTO -> WeekStartPref.Auto
+    else -> DayOfWeek.entries.firstOrNull { it.name == stored }
+        ?.let { WeekStartPref.Day(it) } ?: WeekStartPref.Auto
+}
+
+private const val NONE = "none"
+private const val ENTRY_SEP = ";"
+private const val KEY_VALUE_SEP = "="
+private const val LIST_SEP = ","
+
+/** Distinct, ascending lead times — the canonical form stored and resolved. */
+private fun List<Int>.normalizeReminders(): List<Int> = distinct().sorted()
+
+/**
+ * Parse a stored reminder value into lead times. `null`/empty/"none" → empty
+ * list; a comma-joined list → its minutes; a legacy single value ("30") → a
+ * one-element list. Non-numeric parts are dropped defensively.
+ */
+private fun String?.toReminderList(): List<Int> = when {
+    this == null || isEmpty() || this == NONE -> emptyList()
+    else -> split(LIST_SEP).mapNotNull { it.trim().toIntOrNull() }.normalizeReminders()
+}
+
+/** Serialise lead times for storage: "none" when empty, else comma-joined. */
+private fun List<Int>.toStoredReminders(): String =
+    if (isEmpty()) NONE else normalizeReminders().joinToString(LIST_SEP) { it.toString() }
+
+private fun parseReminderOverrides(stored: String?): Map<Long, List<Int>> {
+    if (stored.isNullOrBlank()) return emptyMap()
+    return stored.split(ENTRY_SEP).mapNotNull { entry ->
+        val parts = entry.split(KEY_VALUE_SEP).takeIf { it.size == 2 } ?: return@mapNotNull null
+        val id = parts[0].toLongOrNull() ?: return@mapNotNull null
+        // Only the deliberate "none" sentinel means an explicit no-reminder
+        // override (empty list); a non-sentinel value that parses to no valid
+        // minutes is garbage and drops the entry, so the calendar inherits the
+        // global default rather than silently reading as "no reminder".
+        when (val value = parts[1]) {
+            NONE -> id to emptyList()
+            else -> value.toReminderList().takeIf { it.isNotEmpty() }?.let { id to it }
+                ?: return@mapNotNull null
+        }
+    }.toMap()
+}
+
+private fun serializeReminderOverrides(map: Map<Long, List<Int>>): String =
+    map.entries.joinToString(ENTRY_SEP) { (id, minutes) -> "$id$KEY_VALUE_SEP${minutes.toStoredReminders()}" }
+
+private inline fun <reified E : Enum<E>> String?.toEnum(default: E): E =
+    this?.let { stored -> enumValues<E>().firstOrNull { it.name == stored } } ?: default

app/src/main/java/de/jeanlucmakiola/calendula/data/reminders/EventReminderReceiver.kt

@@ -0,0 +1,92 @@
+package de.jeanlucmakiola.calendula.data.reminders
+
+import android.Manifest
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import android.content.pm.PackageManager
+import android.provider.CalendarContract
+import androidx.core.content.ContextCompat
+import dagger.hilt.android.AndroidEntryPoint
+import de.jeanlucmakiola.calendula.data.prefs.CalendarPrefs
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.launch
+import javax.inject.Inject
+
+/**
+ * True when [this] alert belongs to a calendar the user disabled in-app, so its
+ * reminder must be suppressed (mirroring the event filtering in
+ * CalendarRepositoryImpl). Alerts whose calendar is unknown (id 0L — e.g. a
+ * pre-upgrade snooze PendingIntent minted before EXTRA_CALENDAR_ID existed) are
+ * never treated as disabled. This is the one predicate the disabled-calendar
+ * gate is built from: [postableAlerts] here and the choke point in
+ * [ReminderNotifier.post] both use it.
+ */
+internal fun ReminderAlert.isForDisabledCalendar(disabledCalendarIds: Set<Long>): Boolean =
+    calendarId != 0L && calendarId in disabledCalendarIds
+
+/**
+ * The due alerts that should actually surface as notifications: everything
+ * except alerts whose calendar the user has disabled in-app. The caller still
+ * marks the full due set fired, so suppressed alerts are not re-broadcast by the
+ * provider.
+ */
+internal fun postableAlerts(
+    due: List<ReminderAlert>,
+    disabledCalendarIds: Set<Long>,
+): List<ReminderAlert> = due.filterNot { it.isForDisabledCalendar(disabledCalendarIds) }
+
+/**
+ * Becomes the app that turns the calendar provider's reminder alarms into
+ * visible notifications (the Etar model — the provider broadcasts
+ * `EVENT_REMINDER` at reminder time but posts nothing itself).
+ *
+ * The broadcast's data URI only carries the alarm time, so it is ignored:
+ * we query every still-scheduled, due `CalendarAlerts` row ourselves, post
+ * them, and mark them fired. Posting happens before marking — a crash in
+ * between re-posts silently (same tag) rather than losing the reminder.
+ */
+@AndroidEntryPoint
+class EventReminderReceiver : BroadcastReceiver() {
+
+    @Inject lateinit var alertStore: ReminderAlertStore
+    @Inject lateinit var notifier: ReminderNotifier
+    @Inject lateinit var settingsPrefs: SettingsPrefs
+    @Inject lateinit var calendarPrefs: CalendarPrefs
+    @Inject lateinit var suppressedStore: SuppressedReminderStore
+
+    override fun onReceive(context: Context, intent: Intent) {
+        if (intent.action != CalendarContract.ACTION_EVENT_REMINDER) return
+        val readGranted = ContextCompat.checkSelfPermission(
+            context, Manifest.permission.READ_CALENDAR,
+        ) == PackageManager.PERMISSION_GRANTED
+        if (!readGranted || !notifier.canPost()) return
+
+        val pendingResult = goAsync()
+        CoroutineScope(SupervisorJob() + Dispatchers.IO).launch {
+            try {
+                if (settingsPrefs.remindersEnabled.first()) {
+                    val now = System.currentTimeMillis()
+                    val due = alertStore.dueAlerts(now)
+                    val disabled = calendarPrefs.disabledCalendarIds.first()
+                    val postable = postableAlerts(due, disabled)
+                    // Suppress reminders for disabled calendars, but still mark
+                    // every due alert fired so the provider stops re-broadcasting
+                    // the suppressed ones. Stash those suppressed alerts so
+                    // re-enabling their calendar can recover them (they would
+                    // otherwise stay STATE_FIRED forever with no re-scan).
+                    postable.forEach { notifier.post(it) }
+                    alertStore.markFired(due.map { it.alertId }, now)
+                    suppressedStore.stash(due - postable.toSet(), now)
+                    suppressedStore.purgeExpired(now)
+                }
+            } finally {
+                pendingResult.finish()
+            }
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/reminders/ReminderActionReceiver.kt

@@ -0,0 +1,127 @@
+package de.jeanlucmakiola.calendula.data.reminders
+
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import dagger.hilt.android.AndroidEntryPoint
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.launch
+import javax.inject.Inject
+
+/**
+ * Handles the "Snooze" and "Dismiss" actions on a reminder notification, plus
+ * the internal re-show when a snooze elapses. All three are app-internal
+ * intents (notification action buttons and our own [ReminderSnoozeScheduler]
+ * alarm), so the receiver is not exported.
+ *
+ * - **Dismiss** just cancels the notification — the `CalendarAlerts` row is
+ *   already fired, so nothing re-posts it.
+ * - **Snooze** cancels the notification and schedules an exact alarm to re-show
+ *   it after the user's snooze delay.
+ * - **Show** (the alarm) re-posts the same notification, so the user can snooze
+ *   or dismiss it again.
+ */
+@AndroidEntryPoint
+class ReminderActionReceiver : BroadcastReceiver() {
+
+    @Inject lateinit var notifier: ReminderNotifier
+    @Inject lateinit var scheduler: ReminderSnoozeScheduler
+    @Inject lateinit var settingsPrefs: SettingsPrefs
+
+    override fun onReceive(context: Context, intent: Intent) {
+        val alert = alertFrom(intent) ?: return
+        when (intent.action) {
+            ACTION_DISMISS -> notifier.cancel(alert)
+
+            ACTION_SNOOZE -> {
+                // Cancel now so the notification doesn't linger until the alarm;
+                // the snooze delay read is the only async work.
+                notifier.cancel(alert)
+                val pendingResult = goAsync()
+                CoroutineScope(SupervisorJob() + Dispatchers.IO).launch {
+                    try {
+                        val minutes = settingsPrefs.snoozeMinutes.first()
+                        val triggerAt = System.currentTimeMillis() + minutes * 60_000L
+                        scheduler.schedule(alert, triggerAt)
+                    } finally {
+                        pendingResult.finish()
+                    }
+                }
+            }
+
+            ACTION_SHOW -> {
+                val pendingResult = goAsync()
+                CoroutineScope(SupervisorJob() + Dispatchers.IO).launch {
+                    try {
+                        if (settingsPrefs.remindersEnabled.first() && notifier.canPost()) {
+                            notifier.post(alert)
+                        }
+                    } finally {
+                        pendingResult.finish()
+                    }
+                }
+            }
+        }
+    }
+
+    companion object {
+        const val ACTION_SNOOZE = "de.jeanlucmakiola.calendula.reminders.SNOOZE"
+        const val ACTION_DISMISS = "de.jeanlucmakiola.calendula.reminders.DISMISS"
+        const val ACTION_SHOW = "de.jeanlucmakiola.calendula.reminders.SHOW"
+
+        private const val EXTRA_ALERT_ID = "alert_id"
+        private const val EXTRA_EVENT_ID = "event_id"
+        private const val EXTRA_CALENDAR_ID = "calendar_id"
+        private const val EXTRA_BEGIN = "begin"
+        private const val EXTRA_END = "end"
+        private const val EXTRA_TITLE = "title"
+        private const val EXTRA_LOCATION = "location"
+        private const val EXTRA_ALL_DAY = "all_day"
+
+        /** An explicit intent to this receiver carrying [alert] as extras. */
+        fun intent(context: Context, action: String, alert: ReminderAlert): Intent =
+            Intent(context, ReminderActionReceiver::class.java).apply {
+                this.action = action
+                putExtra(EXTRA_ALERT_ID, alert.alertId)
+                putExtra(EXTRA_EVENT_ID, alert.eventId)
+                putExtra(EXTRA_CALENDAR_ID, alert.calendarId)
+                putExtra(EXTRA_BEGIN, alert.beginMillis)
+                putExtra(EXTRA_END, alert.endMillis)
+                putExtra(EXTRA_TITLE, alert.title)
+                putExtra(EXTRA_LOCATION, alert.location)
+                putExtra(EXTRA_ALL_DAY, alert.isAllDay)
+            }
+
+        /**
+         * A stable request code per (alert, action) so the three PendingIntents
+         * of one notification stay distinct and don't clobber each other.
+         */
+        fun requestCode(alert: ReminderAlert, action: String): Int {
+            val actionOffset = when (action) {
+                ACTION_SNOOZE -> 1
+                ACTION_DISMISS -> 2
+                ACTION_SHOW -> 3
+                else -> 0
+            }
+            return alert.alertId.toInt() * 8 + actionOffset
+        }
+
+        private fun alertFrom(intent: Intent): ReminderAlert? {
+            if (!intent.hasExtra(EXTRA_ALERT_ID)) return null
+            return ReminderAlert(
+                alertId = intent.getLongExtra(EXTRA_ALERT_ID, 0L),
+                eventId = intent.getLongExtra(EXTRA_EVENT_ID, 0L),
+                calendarId = intent.getLongExtra(EXTRA_CALENDAR_ID, 0L),
+                beginMillis = intent.getLongExtra(EXTRA_BEGIN, 0L),
+                endMillis = intent.getLongExtra(EXTRA_END, 0L),
+                title = intent.getStringExtra(EXTRA_TITLE).orEmpty(),
+                location = intent.getStringExtra(EXTRA_LOCATION),
+                isAllDay = intent.getBooleanExtra(EXTRA_ALL_DAY, false),
+            )
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/reminders/ReminderAlertStore.kt

@@ -0,0 +1,115 @@
+package de.jeanlucmakiola.calendula.data.reminders
+
+import android.content.ContentValues
+import android.content.Context
+import android.provider.CalendarContract
+import android.util.Log
+import dagger.hilt.android.qualifiers.ApplicationContext
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * One due row of the provider's `CalendarAlerts` table (a join with Events).
+ * Stays in the data layer: alerts feed the notification path only and never
+ * reach a screen, so there is no domain model for them.
+ */
+data class ReminderAlert(
+    val alertId: Long,
+    val eventId: Long,
+    val calendarId: Long,
+    val beginMillis: Long,
+    val endMillis: Long,
+    /** Raw event title; may be blank — the notifier substitutes "(no title)". */
+    val title: String,
+    val location: String?,
+    val isAllDay: Boolean,
+)
+
+/**
+ * Seam over the `CalendarAlerts` table so the receiver logic can be exercised
+ * without a ContentResolver. The provider creates these rows itself — only
+ * for `METHOD_ALERT` reminders (verified in AOSP `CalendarAlarmManager`), so
+ * email reminders never show up here.
+ */
+interface ReminderAlertStore {
+
+    /** Alerts that are due (`ALARM_TIME` has passed) and still unhandled. */
+    fun dueAlerts(nowMillis: Long): List<ReminderAlert>
+
+    /**
+     * Mark the given alerts handled (`STATE_FIRED`) so a later broadcast does
+     * not surface them again. Best effort: this write needs `WRITE_CALENDAR`,
+     * which the user may have declined — then re-broadcasts silently replace
+     * the already-posted notifications instead (same tag, alert-once).
+     */
+    fun markFired(alertIds: List<Long>, nowMillis: Long)
+}
+
+@Singleton
+class AndroidReminderAlertStore @Inject constructor(
+    @ApplicationContext private val context: Context,
+) : ReminderAlertStore {
+
+    override fun dueAlerts(nowMillis: Long): List<ReminderAlert> = context.contentResolver.query(
+        CalendarContract.CalendarAlerts.CONTENT_URI,
+        PROJECTION,
+        CalendarContract.CalendarAlerts.STATE + " = ? AND " +
+            CalendarContract.CalendarAlerts.ALARM_TIME + " <= ?",
+        arrayOf(
+            CalendarContract.CalendarAlerts.STATE_SCHEDULED.toString(),
+            nowMillis.toString(),
+        ),
+        CalendarContract.CalendarAlerts.BEGIN + " ASC",
+    )?.use { c ->
+        buildList {
+            while (c.moveToNext()) {
+                add(
+                    ReminderAlert(
+                        alertId = c.getLong(0),
+                        eventId = c.getLong(1),
+                        calendarId = c.getLong(2),
+                        beginMillis = c.getLong(3),
+                        endMillis = c.getLong(4),
+                        title = c.getString(5).orEmpty(),
+                        location = c.getString(6)?.takeIf { it.isNotBlank() },
+                        isAllDay = c.getInt(7) == 1,
+                    ),
+                )
+            }
+        }
+    } ?: emptyList()
+
+    override fun markFired(alertIds: List<Long>, nowMillis: Long) {
+        if (alertIds.isEmpty()) return
+        val values = ContentValues().apply {
+            put(CalendarContract.CalendarAlerts.STATE, CalendarContract.CalendarAlerts.STATE_FIRED)
+            put(CalendarContract.CalendarAlerts.RECEIVED_TIME, nowMillis)
+            put(CalendarContract.CalendarAlerts.NOTIFY_TIME, nowMillis)
+        }
+        try {
+            context.contentResolver.update(
+                CalendarContract.CalendarAlerts.CONTENT_URI,
+                values,
+                CalendarContract.CalendarAlerts._ID +
+                    " IN (" + alertIds.joinToString(",") + ")",
+                null,
+            )
+        } catch (e: SecurityException) {
+            Log.w(TAG, "Cannot mark alerts fired without WRITE_CALENDAR", e)
+        }
+    }
+
+    private companion object {
+        const val TAG = "ReminderAlertStore"
+        val PROJECTION = arrayOf(
+            CalendarContract.CalendarAlerts._ID,
+            CalendarContract.CalendarAlerts.EVENT_ID,
+            CalendarContract.CalendarAlerts.CALENDAR_ID,
+            CalendarContract.CalendarAlerts.BEGIN,
+            CalendarContract.CalendarAlerts.END,
+            CalendarContract.CalendarAlerts.TITLE,
+            CalendarContract.CalendarAlerts.EVENT_LOCATION,
+            CalendarContract.CalendarAlerts.ALL_DAY,
+        )
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/reminders/ReminderNotifier.kt

@@ -0,0 +1,138 @@
+package de.jeanlucmakiola.calendula.data.reminders
+
+import android.Manifest
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.app.PendingIntent
+import android.content.Context
+import android.content.pm.PackageManager
+import android.os.Build
+import android.util.Log
+import androidx.core.app.NotificationCompat
+import androidx.core.app.NotificationManagerCompat
+import androidx.core.content.ContextCompat
+import dagger.hilt.android.qualifiers.ApplicationContext
+import de.jeanlucmakiola.calendula.MainActivity
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.data.prefs.CalendarPrefs
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import de.jeanlucmakiola.calendula.data.prefs.is24Hour
+import kotlinx.coroutines.flow.first
+import java.time.ZoneId
+import java.util.Locale
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Posts one notification per due reminder alert on a dedicated channel.
+ * Tapping opens the event's detail screen; the tag is the alert id, so a
+ * re-broadcast of an alert we couldn't mark fired replaces its notification
+ * silently ([NotificationCompat.Builder.setOnlyAlertOnce]) instead of
+ * duplicating it.
+ */
+@Singleton
+class ReminderNotifier @Inject constructor(
+    @ApplicationContext private val context: Context,
+    private val settingsPrefs: SettingsPrefs,
+    private val calendarPrefs: CalendarPrefs,
+) {
+
+    /** False when the user declined `POST_NOTIFICATIONS` or muted the app. */
+    fun canPost(): Boolean {
+        val granted = Build.VERSION.SDK_INT < Build.VERSION_CODES.TIRAMISU ||
+            ContextCompat.checkSelfPermission(context, Manifest.permission.POST_NOTIFICATIONS) ==
+            PackageManager.PERMISSION_GRANTED
+        return granted && NotificationManagerCompat.from(context).areNotificationsEnabled()
+    }
+
+    suspend fun post(alert: ReminderAlert) {
+        // The single choke point for the disabled-calendar gate: it covers both
+        // the provider broadcast (EventReminderReceiver) and a snoozed re-show
+        // (ReminderActionReceiver), so a calendar disabled after a snooze no
+        // longer notifies — without either receiver duplicating the check.
+        if (alert.isForDisabledCalendar(calendarPrefs.disabledCalendarIds.first())) return
+        ensureChannel()
+        val title = alert.title.ifBlank { context.getString(R.string.event_untitled) }
+        val is24Hour = settingsPrefs.timeFormat.first()
+            .is24Hour(android.text.format.DateFormat.is24HourFormat(context))
+        val time = reminderTimeText(
+            beginMillis = alert.beginMillis,
+            endMillis = alert.endMillis,
+            isAllDay = alert.isAllDay,
+            zone = ZoneId.systemDefault(),
+            locale = Locale.getDefault(),
+            is24Hour = is24Hour,
+        )
+        val text = listOfNotNull(time, alert.location).joinToString(" · ")
+        val notification = NotificationCompat.Builder(context, CHANNEL_ID)
+            .setSmallIcon(R.drawable.ic_notification)
+            .setContentTitle(title)
+            .setContentText(text)
+            .setWhen(alert.beginMillis)
+            .setShowWhen(false)
+            .setCategory(NotificationCompat.CATEGORY_EVENT)
+            .setPriority(NotificationCompat.PRIORITY_HIGH)
+            .setAutoCancel(true)
+            .setOnlyAlertOnce(true)
+            .setContentIntent(detailIntent(alert))
+            .addAction(
+                R.drawable.ic_notification_snooze,
+                context.getString(R.string.reminder_action_snooze),
+                actionIntent(alert, ReminderActionReceiver.ACTION_SNOOZE),
+            )
+            .addAction(
+                R.drawable.ic_notification_dismiss,
+                context.getString(R.string.reminder_action_dismiss),
+                actionIntent(alert, ReminderActionReceiver.ACTION_DISMISS),
+            )
+            .build()
+        try {
+            NotificationManagerCompat.from(context)
+                .notify(alert.alertId.toString(), NOTIFICATION_ID, notification)
+        } catch (e: SecurityException) {
+            // POST_NOTIFICATIONS was revoked between canPost() and here.
+            Log.w(TAG, "Could not post reminder for event ${alert.eventId}", e)
+        }
+    }
+
+    /** Remove a posted reminder (snooze re-shows it later; dismiss is final). */
+    fun cancel(alert: ReminderAlert) {
+        NotificationManagerCompat.from(context).cancel(alert.alertId.toString(), NOTIFICATION_ID)
+    }
+
+    private fun actionIntent(alert: ReminderAlert, action: String): PendingIntent =
+        PendingIntent.getBroadcast(
+            context,
+            ReminderActionReceiver.requestCode(alert, action),
+            ReminderActionReceiver.intent(context, action, alert),
+            PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE,
+        )
+
+    private fun detailIntent(alert: ReminderAlert): PendingIntent = PendingIntent.getActivity(
+        context,
+        /* requestCode = */ alert.alertId.toInt(),
+        MainActivity.eventDetailIntent(context, alert.eventId, alert.beginMillis, alert.endMillis),
+        PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE,
+    )
+
+    /** Channel creation is idempotent; re-running refreshes the localized name. */
+    private fun ensureChannel() {
+        val channel = NotificationChannel(
+            CHANNEL_ID,
+            context.getString(R.string.reminder_channel_name),
+            NotificationManager.IMPORTANCE_HIGH,
+        ).apply {
+            description = context.getString(R.string.reminder_channel_description)
+        }
+        NotificationManagerCompat.from(context).createNotificationChannel(channel)
+    }
+
+    private companion object {
+        const val TAG = "ReminderNotifier"
+        const val CHANNEL_ID = "reminders"
+
+        // One id, distinct tags: the tag (alert id) already keys the
+        // notification, so a fixed id keeps cancellation/replacement simple.
+        const val NOTIFICATION_ID = 1
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/reminders/ReminderSnoozeScheduler.kt

@@ -0,0 +1,55 @@
+package de.jeanlucmakiola.calendula.data.reminders
+
+import android.app.AlarmManager
+import android.app.PendingIntent
+import android.content.Context
+import android.os.Build
+import androidx.core.content.getSystemService
+import dagger.hilt.android.qualifiers.ApplicationContext
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Schedules a one-off exact alarm that re-shows a snoozed reminder.
+ *
+ * The app otherwise relies entirely on the calendar provider's `EVENT_REMINDER`
+ * broadcast (the Etar model), but a snoozed reminder has no provider backing —
+ * its `CalendarAlerts` row is already fired — so we must re-fire it ourselves.
+ * A snooze that lands late is a broken snooze, hence an *exact* alarm; we fall
+ * back to an inexact allow-while-idle alarm only if the OS withholds the
+ * exact-alarm capability (API 31–32 where the user revoked it).
+ */
+@Singleton
+class ReminderSnoozeScheduler @Inject constructor(
+    @ApplicationContext private val context: Context,
+) {
+
+    fun schedule(alert: ReminderAlert, triggerAtMillis: Long) {
+        val alarmManager = context.getSystemService<AlarmManager>() ?: return
+        val pendingIntent = PendingIntent.getBroadcast(
+            context,
+            ReminderActionReceiver.requestCode(alert, ReminderActionReceiver.ACTION_SHOW),
+            ReminderActionReceiver.intent(context, ReminderActionReceiver.ACTION_SHOW, alert),
+            PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE,
+        )
+        if (canScheduleExact(alarmManager)) {
+            alarmManager.setExactAndAllowWhileIdle(
+                AlarmManager.RTC_WAKEUP, triggerAtMillis, pendingIntent,
+            )
+        } else {
+            // Exact alarms revoked (API 31–32): an inexact wake is the honest
+            // best we can do without nagging for SCHEDULE_EXACT_ALARM.
+            alarmManager.setAndAllowWhileIdle(
+                AlarmManager.RTC_WAKEUP, triggerAtMillis, pendingIntent,
+            )
+        }
+    }
+
+    /**
+     * True on API < 31 (no restriction), and on 31+ when the exact-alarm
+     * capability is held — auto-granted via `USE_EXACT_ALARM` on API 33+
+     * (Calendula is a calendar app), user-revocable on 31–32.
+     */
+    private fun canScheduleExact(alarmManager: AlarmManager): Boolean =
+        Build.VERSION.SDK_INT < Build.VERSION_CODES.S || alarmManager.canScheduleExactAlarms()
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/reminders/ReminderTimeText.kt

@@ -0,0 +1,60 @@
+package de.jeanlucmakiola.calendula.data.reminders
+
+import de.jeanlucmakiola.calendula.ui.common.timeOfDayFormatter
+import java.time.Instant
+import java.time.ZoneId
+import java.time.ZoneOffset
+import java.time.format.DateTimeFormatter
+import java.time.format.FormatStyle
+import java.util.Locale
+
+/**
+ * The one line of time context in a reminder notification. Pure so it can be
+ * JVM-tested:
+ *
+ * - timed, same day:      "09:30 – 10:00"
+ * - timed, crossing days: "11 Jun, 23:30 – 12 Jun, 00:30" (medium date + short time)
+ * - all-day, one day:     "11 Jun 2026"
+ * - all-day, multi-day:   "11 Jun 2026 – 12 Jun 2026"
+ *
+ * All-day instances store UTC midnights with an exclusive end, so they are
+ * read in UTC and the end day is the last *covered* day.
+ */
+fun reminderTimeText(
+    beginMillis: Long,
+    endMillis: Long,
+    isAllDay: Boolean,
+    zone: ZoneId,
+    locale: Locale,
+    is24Hour: Boolean,
+): String {
+    if (isAllDay) {
+        val dateFormat = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM).withLocale(locale)
+        // (atZone().toLocalDate() instead of LocalDate.ofInstant — API 34+)
+        val firstDay = Instant.ofEpochMilli(beginMillis).atZone(ZoneOffset.UTC).toLocalDate()
+        val lastDay = Instant.ofEpochMilli(endMillis).atZone(ZoneOffset.UTC).toLocalDate()
+            .minusDays(1)
+            .coerceAtLeast(firstDay)
+        return if (lastDay == firstDay) {
+            dateFormat.format(firstDay)
+        } else {
+            dateFormat.format(firstDay) + RANGE + dateFormat.format(lastDay)
+        }
+    }
+
+    val timeFormat = timeOfDayFormatter(is24Hour, locale)
+    val begin = Instant.ofEpochMilli(beginMillis).atZone(zone)
+    val end = Instant.ofEpochMilli(endMillis).atZone(zone)
+    return if (begin.toLocalDate() == end.toLocalDate()) {
+        timeFormat.format(begin) + RANGE + timeFormat.format(end)
+    } else {
+        // Cross-day: medium date + the chosen short time, joined per side. Built
+        // from the two formatters (not ofLocalizedDateTime) so the 12/24h choice
+        // applies to the time portion too.
+        val dateFormat = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM).withLocale(locale)
+        val dateTime = { z: java.time.ZonedDateTime -> "${dateFormat.format(z)}, ${timeFormat.format(z)}" }
+        dateTime(begin) + RANGE + dateTime(end)
+    }
+}
+
+private const val RANGE = " – "

app/src/main/java/de/jeanlucmakiola/calendula/data/reminders/SuppressedReminderStore.kt

@@ -0,0 +1,130 @@
+package de.jeanlucmakiola.calendula.data.reminders
+
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.MutablePreferences
+import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.core.stringSetPreferencesKey
+import java.util.Base64
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Still relevant while the event has not ended: a reminder for an event that is
+ * already over is pointless to re-surface. Falls back to the begin time when the
+ * end is unknown (0L). Used both to decide what to re-post and to purge the stash.
+ */
+internal fun ReminderAlert.isRelevantAt(nowMillis: Long): Boolean =
+    (endMillis.takeIf { it > 0L } ?: beginMillis) >= nowMillis
+
+/**
+ * Local stash of reminder alerts that fired while their calendar was disabled
+ * in-app. [EventReminderReceiver] marks every due alert `STATE_FIRED` regardless
+ * (so the provider stops re-broadcasting the suppressed ones), which would
+ * otherwise lose those reminders forever — there is no re-scan. Stashing lets
+ * [de.jeanlucmakiola.calendula.ui.calendars.CalendarsViewModel] re-post them if
+ * the user re-enables the calendar before the event is over.
+ *
+ * Persisted in the shared preferences DataStore as a set of self-describing
+ * strings (one per alert); the stash never reaches a screen, so there is no
+ * domain model. Entries whose event has already ended are dropped on the next
+ * stash/recover/purge, so the stash only ever holds a handful of pending alerts.
+ */
+@Singleton
+class SuppressedReminderStore @Inject constructor(
+    private val store: DataStore<Preferences>,
+) {
+
+    /** Add [alerts] to the stash, replacing any existing entry with the same id. */
+    suspend fun stash(alerts: List<ReminderAlert>, nowMillis: Long) {
+        if (alerts.isEmpty()) return
+        store.edit { prefs ->
+            val byId = decodeAll(prefs).associateByTo(mutableMapOf()) { it.alertId }
+            alerts.forEach { byId[it.alertId] = it }
+            prefs.putStash(byId.values.filter { it.isRelevantAt(nowMillis) })
+        }
+    }
+
+    /**
+     * Remove and return the still-relevant stashed alerts belonging to any of
+     * [calendarIds]; drops expired entries for every calendar in passing.
+     */
+    suspend fun recoverFor(calendarIds: Set<Long>, nowMillis: Long): List<ReminderAlert> {
+        val recovered = mutableListOf<ReminderAlert>()
+        store.edit { prefs ->
+            val kept = decodeAll(prefs).filter { alert ->
+                when {
+                    !alert.isRelevantAt(nowMillis) -> false // expired: drop
+                    alert.calendarId in calendarIds -> { recovered += alert; false }
+                    else -> true
+                }
+            }
+            prefs.putStash(kept)
+        }
+        return recovered
+    }
+
+    /** Drop entries whose event has already ended — cheap opportunistic cleanup. */
+    suspend fun purgeExpired(nowMillis: Long) {
+        store.edit { prefs ->
+            prefs.putStash(decodeAll(prefs).filter { it.isRelevantAt(nowMillis) })
+        }
+    }
+
+    private fun decodeAll(prefs: Preferences): List<ReminderAlert> =
+        prefs[KEY].orEmpty().mapNotNull { decodeStashEntry(it) }
+
+    private fun MutablePreferences.putStash(alerts: List<ReminderAlert>) {
+        val encoded = alerts.map { encodeStashEntry(it) }.toSet()
+        if (encoded.isEmpty()) remove(KEY) else set(KEY, encoded)
+    }
+
+    private companion object {
+        val KEY = stringSetPreferencesKey("suppressed_reminders")
+    }
+}
+
+// One stash entry as a delimited string. The '|' separator is safe because every
+// free-text field is Base64-encoded first (that alphabet never contains '|'), and
+// a null location is stored as a distinct sentinel that Base64 also never yields.
+private const val FIELD_SEP = "|"
+private const val NULL_LOCATION = "-"
+
+internal fun encodeStashEntry(alert: ReminderAlert): String = listOf(
+    alert.alertId.toString(),
+    alert.eventId.toString(),
+    alert.calendarId.toString(),
+    alert.beginMillis.toString(),
+    alert.endMillis.toString(),
+    if (alert.isAllDay) "1" else "0",
+    alert.title.toBase64(),
+    alert.location?.toBase64() ?: NULL_LOCATION,
+).joinToString(FIELD_SEP)
+
+/** Reverse of [encodeStashEntry]; returns null for a malformed entry (dropped). */
+internal fun decodeStashEntry(raw: String): ReminderAlert? {
+    val parts = raw.split(FIELD_SEP)
+    if (parts.size != 8) return null
+    return try {
+        ReminderAlert(
+            alertId = parts[0].toLong(),
+            eventId = parts[1].toLong(),
+            calendarId = parts[2].toLong(),
+            beginMillis = parts[3].toLong(),
+            endMillis = parts[4].toLong(),
+            title = parts[6].fromBase64(),
+            location = parts[7].takeIf { it != NULL_LOCATION }?.fromBase64(),
+            isAllDay = parts[5] == "1",
+        )
+    } catch (e: NumberFormatException) {
+        null
+    } catch (e: IllegalArgumentException) { // bad Base64
+        null
+    }
+}
+
+private fun String.toBase64(): String =
+    Base64.getEncoder().encodeToString(toByteArray(Charsets.UTF_8))
+
+private fun String.fromBase64(): String =
+    String(Base64.getDecoder().decode(this), Charsets.UTF_8)

app/src/main/java/de/jeanlucmakiola/calendula/domain/EventForm.kt

@@ -0,0 +1,205 @@
+package de.jeanlucmakiola.calendula.domain
+
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Instant
+
+/**
+ * User input for creating an event (and, from v1.3, editing one). Times are
+ * wall-clock values in the device zone; the data layer translates them to
+ * provider millis (all-day events normalise to UTC midnights there).
+ */
+data class EventForm(
+    val calendarId: Long?,
+    val title: String = "",
+    val isAllDay: Boolean = false,
+    val start: LocalDateTime,
+    val end: LocalDateTime,
+    val location: String = "",
+    val description: String = "",
+    /** Reminder lead times in minutes before the start, deduplicated. */
+    val reminders: List<Int> = emptyList(),
+    val availability: Availability = Availability.Busy,
+    val accessLevel: AccessLevel = AccessLevel.Default,
+    /**
+     * Bare RRULE value (`Events.RRULE` convention, no "RRULE:" prefix); null
+     * means a one-off event. May hold rules the simple picker can't express —
+     * those are kept verbatim until the user picks something else.
+     */
+    val rrule: String? = null,
+    /**
+     * The event's own colour, or null to inherit the calendar's colour.
+     * [colorKey] is a `Colors.COLOR_KEY` from the calendar account's published
+     * event palette (Google, some CalDAV) — written as `EVENT_COLOR_KEY` so it
+     * round-trips through sync. When it is null but [color] is set, [color] is
+     * a raw ARGB written as `EVENT_COLOR` (local calendars, or synced ones the
+     * user opted into despite no palette). [color] mirrors the key's swatch when
+     * [colorKey] is set, so the picker can highlight it.
+     */
+    val colorKey: String? = null,
+    val color: Int? = null,
+    /**
+     * Guests the user has added/kept on the event. Calendula only writes these
+     * `Attendees` rows — it has no INTERNET and never sends an invitation
+     * itself; whether a guest is notified is decided downstream by the
+     * calendar's backend (local: no one; CalDAV/Google: the server/account).
+     * Read-only rows the form doesn't model (the organizer, resources) are
+     * preserved by the data layer, not carried here.
+     */
+    val attendees: List<EventAttendee> = emptyList(),
+)
+
+/**
+ * One editable guest: the user controls the [email] (the identity we dedup and
+ * write on), an optional display [name], and whether they're [optional] rather
+ * than required. Response status and the organizer/resource distinction are not
+ * user-editable, so they aren't modelled here.
+ */
+data class EventAttendee(
+    val email: String,
+    val name: String = "",
+    val optional: Boolean = false,
+)
+
+/**
+ * The form's optional sections. Which ones show by default is a user setting;
+ * the rest unfold behind a "more fields" button.
+ */
+enum class EventFormField {
+    Location,
+    Description,
+    Reminders,
+    Recurrence,
+    Availability,
+    Visibility,
+    Color,
+    Attendees,
+}
+
+enum class EventFormProblem {
+    /** No target calendar — none picked and no writable calendar exists. */
+    NoCalendar,
+    EndBeforeStart,
+    /** The recurrence's UNTIL date lies before the event's first day. */
+    RecurrenceEndsBeforeStart,
+}
+
+/**
+ * Validation; an empty set means the form can be saved. A blank title is
+ * allowed (display falls back to "(No title)", matching the provider), and a
+ * zero-length timed event is allowed (spec §8: instant events exist).
+ */
+/**
+ * Prefill the edit form from a loaded event. [beginMillis]/[endMillis] are the
+ * tapped occurrence's own times (`Instances.BEGIN`/`END`), not the series
+ * start — the data layer later turns a time edit into a delta on the series.
+ *
+ * All-day provider times are UTC midnights with an exclusive end; the form
+ * shows the last covered day and keeps placeholder wall-clock times in case
+ * the user switches the event to timed.
+ */
+fun EventDetail.toEditForm(beginMillis: Long, endMillis: Long, zone: TimeZone): EventForm {
+    val (start, end) = if (instance.isAllDay) {
+        val startDate = Instant.fromEpochMilliseconds(beginMillis)
+            .toLocalDateTime(TimeZone.UTC).date
+        val endExclusive = Instant.fromEpochMilliseconds(endMillis)
+            .toLocalDateTime(TimeZone.UTC).date
+        val endDate = maxOf(startDate, LocalDate.fromEpochDays(endExclusive.toEpochDays() - 1))
+        LocalDateTime(startDate, LocalTime(9, 0)) to LocalDateTime(endDate, LocalTime(10, 0))
+    } else {
+        Instant.fromEpochMilliseconds(beginMillis).toLocalDateTime(zone) to
+            Instant.fromEpochMilliseconds(endMillis).toLocalDateTime(zone)
+    }
+    return EventForm(
+        calendarId = instance.calendarId,
+        title = instance.title,
+        isAllDay = instance.isAllDay,
+        start = start,
+        end = end,
+        location = instance.location.orEmpty(),
+        description = description.orEmpty(),
+        reminders = reminders.map { it.minutes }.distinct().sorted(),
+        availability = availability,
+        accessLevel = accessLevel,
+        rrule = rrule?.removePrefix("RRULE:")?.takeIf { it.isNotBlank() },
+        // The provider fills EVENT_COLOR from the key, so [color] is the
+        // swatch either way; a null colour means the event inherits its
+        // calendar's colour.
+        colorKey = eventColorKey,
+        color = eventColor,
+        // Only editable guests ride in the form: drop the organizer and
+        // resource rows (not user-editable) and any without an email (we key
+        // edits and dedup on the address). The data layer preserves the rows we
+        // don't carry here, so they're never clobbered on save.
+        attendees = attendees
+            .filter {
+                it.relationship != AttendeeRelationship.Organizer &&
+                    it.type != AttendeeType.Resource
+            }
+            .mapNotNull { a ->
+                a.email?.takeIf { it.isNotBlank() }?.let { email ->
+                    EventAttendee(
+                        email = email,
+                        name = a.name,
+                        optional = a.type == AttendeeType.Optional,
+                    )
+                }
+            },
+    )
+}
+
+/**
+ * What the edit form saw when it loaded — compared against a fresh read at
+ * save time to detect external changes (sync, another device) that landed
+ * while the form was open. The raw row times ride along because
+ * [toEditForm] derives the form's times from the *tapped occurrence*, so
+ * re-deriving with the same occurrence would mask an externally moved
+ * event. Guests are covered (the form writes editable attendees), so an
+ * external attendee change now also trips the conflict check. Still not
+ * covered: status, the user's own response, reminder methods, the
+ * organizer/resource rows, and a recurring event's duration.
+ */
+data class EditSnapshot(
+    val form: EventForm,
+    /** The raw Events-row times (for recurring events: the series anchor). */
+    val rowStart: Instant,
+    val rowEnd: Instant,
+)
+
+fun EventDetail.toEditSnapshot(beginMillis: Long, endMillis: Long, zone: TimeZone): EditSnapshot =
+    EditSnapshot(
+        form = toEditForm(beginMillis, endMillis, zone),
+        rowStart = instance.start,
+        rowEnd = instance.end,
+    )
+
+/**
+ * The optional sections that hold a value in [form] — when editing, these
+ * must be visible regardless of the user's default-fields setting, or the
+ * data they carry would be invisible (though still preserved).
+ */
+fun EventForm.populatedFields(): Set<EventFormField> = buildSet {
+    if (location.isNotBlank()) add(EventFormField.Location)
+    if (description.isNotBlank()) add(EventFormField.Description)
+    if (reminders.isNotEmpty()) add(EventFormField.Reminders)
+    if (rrule != null) add(EventFormField.Recurrence)
+    if (availability != Availability.Busy) add(EventFormField.Availability)
+    if (accessLevel != AccessLevel.Default) add(EventFormField.Visibility)
+    if (colorKey != null || color != null) add(EventFormField.Color)
+    if (attendees.isNotEmpty()) add(EventFormField.Attendees)
+}
+
+fun EventForm.problems(): Set<EventFormProblem> = buildSet {
+    if (calendarId == null) add(EventFormProblem.NoCalendar)
+    val endsTooEarly = if (isAllDay) end.date < start.date else end < start
+    if (endsTooEarly) add(EventFormProblem.EndBeforeStart)
+    // An UNTIL before the first day would make the provider generate zero
+    // occurrences — the event would silently vanish from every view.
+    val recurrenceEnd = rrule?.let(::parseSimpleRecurrence)?.end
+    if (recurrenceEnd is RecurrenceEnd.Until && recurrenceEnd.date < start.date) {
+        add(EventFormProblem.RecurrenceEndsBeforeStart)
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/domain/FontRole.kt

@@ -0,0 +1,8 @@
+package de.jeanlucmakiola.calendula.domain
+
+/**
+ * The two Material 3 typeface roles a user can set independently (issue #19):
+ * [BRAND] drives the display/headline styles (expression), [PLAIN] the
+ * title/body/label styles (readability). Each defaults to the system typeface.
+ */
+enum class FontRole { BRAND, PLAIN }

app/src/main/java/de/jeanlucmakiola/calendula/domain/Models.kt

@@ -9,6 +9,31 @@ data class CalendarSource(
     val accountType: String,
     val color: Int,
     val isVisibleInSystem: Boolean,
+    /**
+     * Whether events in this calendar can be created/edited/deleted
+     * (`Calendars.CALENDAR_ACCESS_LEVEL` >= contributor). False for WebCal
+     * subscriptions, birthday calendars and other read-only sources.
+     */
+    val canModifyContents: Boolean = false,
+    /**
+     * A device-only calendar the app itself owns (`ACCOUNT_TYPE_LOCAL`): it has
+     * no sync backend, so the app can rename / recolor / delete it. Synced
+     * calendars (Google, DAVx5, …) are managed in their own source app instead.
+     */
+    val isLocal: Boolean = false,
+    /**
+     * Free-text note for a local calendar (stored in `CAL_SYNC1`, which the app
+     * owns for its own calendars). Always null for synced calendars.
+     */
+    val description: String? = null,
+    /**
+     * A special-dates mirror calendar the app manages (birthdays/anniversaries
+     * from contacts). Its events' title/date/recurrence are owned by the sync,
+     * so it's hidden from the new-event calendar picker and its events lock those
+     * fields in the editor. Recognised by a durable provider marker, so it holds
+     * even after a backup restore clears the app's stored ids.
+     */
+    val isManaged: Boolean = false,
 )
 
 data class EventInstance(
@@ -23,18 +48,65 @@ data class EventInstance(
     val location: String?,
 )
 
+/**
+ * Whether this event has finished relative to [now] — its end is at or before
+ * the current instant. An in-progress event (already started but not yet ended)
+ * is *not* considered ended. All-day events end at the exclusive next-midnight,
+ * so they only count as ended once their day is fully over.
+ */
+fun EventInstance.hasEnded(now: Instant): Boolean = end <= now
+
 data class EventDetail(
     val instance: EventInstance,
     val description: String?,
     val organizer: String?,
     val attendees: List<Attendee>,
     val rrule: String?,
+    /** Reminders (VALARM) configured on the event, ascending lead time. */
+    val reminders: List<Reminder> = emptyList(),
+    /** Confirmed / Tentative / Cancelled (`Events.STATUS`). */
+    val status: EventStatus = EventStatus.Confirmed,
+    /** Busy / Free (`Events.AVAILABILITY`, the iCal TRANSP field). */
+    val availability: Availability = Availability.Busy,
+    /** Default / Private / Confidential / Public (`Events.ACCESS_LEVEL`). */
+    val accessLevel: AccessLevel = AccessLevel.Default,
+    /** Raw zone id (`Events.EVENT_TIMEZONE`), e.g. "Europe/Berlin"; null if unset. */
+    val eventTimezone: String? = null,
+    /** This device user's own response (`Events.SELF_ATTENDEE_STATUS`). */
+    val selfStatus: AttendeeStatus = AttendeeStatus.Unknown,
+    /**
+     * The event's own raw colour (`Events.EVENT_COLOR`), null when the event
+     * inherits its calendar's colour. Unlike [EventInstance.color] (which
+     * already folds in the calendar fallback for display) this stays null so
+     * the edit form can tell "has own colour" from "inherits".
+     */
+    val eventColor: Int? = null,
+    /** The event's `Events.EVENT_COLOR_KEY` (a calendar-palette key), or null. */
+    val eventColorKey: String? = null,
 )
 
+/**
+ * One selectable event colour published by a calendar's account
+ * (`CalendarContract.Colors`, `TYPE_EVENT`): [key] is the account-scoped
+ * `COLOR_KEY` written as `EVENT_COLOR_KEY` (so the colour survives sync),
+ * [argb] is the swatch it renders as.
+ */
+data class EventColorOption(val key: String, val argb: Int)
+
 data class Attendee(
     val name: String,
     val email: String?,
     val status: AttendeeStatus,
+    /** Organizer / performer / speaker / plain attendee (`ATTENDEE_RELATIONSHIP`). */
+    val relationship: AttendeeRelationship = AttendeeRelationship.None,
+    /** Required / optional / resource (`ATTENDEE_TYPE`). */
+    val type: AttendeeType = AttendeeType.None,
+)
+
+data class Reminder(
+    /** Lead time before the event start, in minutes. `-1` means the provider default. */
+    val minutes: Int,
+    val method: ReminderMethod,
 )
 
 enum class AttendeeStatus {
@@ -45,6 +117,58 @@ enum class AttendeeStatus {
     Unknown,
 }
 
+enum class AttendeeRelationship {
+    Organizer,
+    Attendee,
+    Performer,
+    Speaker,
+    None,
+}
+
+enum class AttendeeType {
+    Required,
+    Optional,
+    Resource,
+    None,
+}
+
+enum class ReminderMethod {
+    Alert,
+    Email,
+    Sms,
+    Alarm,
+    Default,
+}
+
+enum class EventStatus {
+    Confirmed,
+    Tentative,
+    Cancelled,
+}
+
+enum class Availability {
+    Busy,
+    Free,
+    Tentative,
+}
+
+enum class AccessLevel {
+    Default,
+    Public,
+    Private,
+    Confidential,
+}
+
+/**
+ * How far a write to a recurring event reaches. Non-recurring events always
+ * use [AllEvents] (there is only one).
+ */
+enum class RecurringWriteScope {
+    ThisEvent,
+    ThisAndFollowing,
+    AllEvents,
+}
+
 enum class FailureReason {
     PermissionRevoked,
     NoCalendarsConfigured,

app/src/main/java/de/jeanlucmakiola/calendula/domain/Recurrence.kt

@@ -0,0 +1,197 @@
+package de.jeanlucmakiola.calendula.domain
+
+import kotlinx.datetime.DayOfWeek
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.isoDayNumber
+import kotlinx.datetime.number
+import kotlinx.datetime.toInstant
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Instant
+
+/**
+ * The recurrence shapes the simple picker can express (v1.3): a frequency,
+ * an interval, weekly weekday picks, and an optional end. Anything beyond
+ * that (ordinal BYDAY like "2TH", BYMONTHDAY, EXDATE rules, …) stays a raw
+ * RRULE string the picker shows as "custom" and leaves untouched unless the
+ * user replaces it.
+ */
+data class SimpleRecurrence(
+    val freq: RecurrenceFreq,
+    val interval: Int = 1,
+    val end: RecurrenceEnd = RecurrenceEnd.Never,
+    /**
+     * Weekly only: the weekdays the rule fires on (RRULE BYDAY). Empty means
+     * no BYDAY part — the provider derives the day from DTSTART.
+     */
+    val byDays: Set<DayOfWeek> = emptySet(),
+)
+
+enum class RecurrenceFreq {
+    Daily,
+    Weekly,
+    Monthly,
+    Yearly,
+}
+
+sealed interface RecurrenceEnd {
+    data object Never : RecurrenceEnd
+
+    /** Last day on which an occurrence may fall (inclusive). */
+    data class Until(val date: LocalDate) : RecurrenceEnd
+
+    /** Total number of occurrences, counting the first. */
+    data class Count(val times: Int) : RecurrenceEnd
+}
+
+/**
+ * Parse an RRULE into the picker's simple shape, or null when the rule uses
+ * parts the picker can't represent (so the UI preserves the original string).
+ * Accepts an optional leading "RRULE:" and an ignored WKST part. A datetime
+ * UNTIL is converted from UTC into [zone] before its date is taken, mirroring
+ * [toRRule].
+ */
+fun parseSimpleRecurrence(
+    rrule: String,
+    zone: TimeZone = TimeZone.currentSystemDefault(),
+): SimpleRecurrence? {
+    val parts = rrule.removePrefix("RRULE:").split(';')
+        .filter { it.isNotBlank() }
+        .associate { token ->
+            val eq = token.indexOf('=')
+            if (eq <= 0) return null
+            token.substring(0, eq).uppercase() to token.substring(eq + 1)
+        }
+    if (parts.keys.any { it !in setOf("FREQ", "INTERVAL", "UNTIL", "COUNT", "WKST", "BYDAY") }) {
+        return null
+    }
+
+    val freq = when (parts["FREQ"]?.uppercase()) {
+        "DAILY" -> RecurrenceFreq.Daily
+        "WEEKLY" -> RecurrenceFreq.Weekly
+        "MONTHLY" -> RecurrenceFreq.Monthly
+        "YEARLY" -> RecurrenceFreq.Yearly
+        else -> return null
+    }
+    val interval = parts["INTERVAL"]?.let { it.toIntOrNull()?.takeIf { n -> n >= 1 } ?: return null } ?: 1
+
+    // BYDAY is simple only as plain weekday picks on a weekly rule; ordinal
+    // forms ("2TH" = second Thursday) and BYDAY on other frequencies are not.
+    val byDays = parts["BYDAY"]?.let { raw ->
+        if (freq != RecurrenceFreq.Weekly) return null
+        raw.split(',').map { token -> rruleDay(token.trim()) ?: return null }.toSet()
+    } ?: emptySet()
+
+    val until = parts["UNTIL"]
+    val count = parts["COUNT"]
+    if (until != null && count != null) return null
+    val end = when {
+        until != null -> RecurrenceEnd.Until(parseUntilDate(until, zone) ?: return null)
+        count != null -> RecurrenceEnd.Count(count.toIntOrNull()?.takeIf { it >= 1 } ?: return null)
+        else -> RecurrenceEnd.Never
+    }
+    return SimpleRecurrence(freq, interval, end, byDays)
+}
+
+/**
+ * Render as a provider-ready RRULE value (no "RRULE:" prefix —
+ * `CalendarContract.Events.RRULE` stores the bare value). UNTIL is written as
+ * the end of the chosen day *in [zone]*, expressed in UTC: the recurrence
+ * engine has been observed applying UNTIL coarsely after converting it into
+ * the event's timezone, so a plain `T235959Z` can leak one extra day for
+ * zones ahead of UTC.
+ */
+fun SimpleRecurrence.toRRule(zone: TimeZone = TimeZone.currentSystemDefault()): String = buildString {
+    append("FREQ=")
+    append(
+        when (freq) {
+            RecurrenceFreq.Daily -> "DAILY"
+            RecurrenceFreq.Weekly -> "WEEKLY"
+            RecurrenceFreq.Monthly -> "MONTHLY"
+            RecurrenceFreq.Yearly -> "YEARLY"
+        },
+    )
+    if (interval > 1) append(";INTERVAL=$interval")
+    if (freq == RecurrenceFreq.Weekly && byDays.isNotEmpty()) {
+        append(";BYDAY=")
+        append(
+            byDays.sortedBy { it.isoDayNumber }
+                .joinToString(",") { RRULE_DAY_CODES.getValue(it) },
+        )
+    }
+    when (val e = end) {
+        RecurrenceEnd.Never -> Unit
+        is RecurrenceEnd.Until -> {
+            val utc = LocalDateTime(e.date, LocalTime(23, 59, 59))
+                .toInstant(zone)
+                .toLocalDateTime(TimeZone.UTC)
+            append(
+                ";UNTIL=%04d%02d%02dT%02d%02d%02dZ".format(
+                    utc.year, utc.month.number, utc.day,
+                    utc.hour, utc.minute, utc.second,
+                ),
+            )
+        }
+        is RecurrenceEnd.Count -> append(";COUNT=${e.times}")
+    }
+}
+
+private val RRULE_DAY_CODES: Map<DayOfWeek, String> = mapOf(
+    DayOfWeek.MONDAY to "MO",
+    DayOfWeek.TUESDAY to "TU",
+    DayOfWeek.WEDNESDAY to "WE",
+    DayOfWeek.THURSDAY to "TH",
+    DayOfWeek.FRIDAY to "FR",
+    DayOfWeek.SATURDAY to "SA",
+    DayOfWeek.SUNDAY to "SU",
+)
+
+/** Exact two-letter BYDAY token → weekday; ordinal forms ("2TH") return null. */
+private fun rruleDay(token: String): DayOfWeek? =
+    RRULE_DAY_CODES.entries.firstOrNull { it.value == token.uppercase() }?.key
+
+/**
+ * End an arbitrary RRULE (simple or not) at [untilUtcMillis]: any existing
+ * UNTIL/COUNT is dropped, every other part (BYDAY, INTERVAL, …) survives.
+ * Used for "delete this and all following occurrences" — the caller passes a
+ * moment just before the first occurrence to remove.
+ */
+fun rruleTruncatedAt(rrule: String, untilUtcMillis: Long): String {
+    val kept = rrule.removePrefix("RRULE:").split(';')
+        .filter { it.isNotBlank() }
+        .filterNot { part ->
+            val key = part.substringBefore('=').trim().uppercase()
+            key == "UNTIL" || key == "COUNT"
+        }
+    val until = Instant.fromEpochMilliseconds(untilUtcMillis).toLocalDateTime(TimeZone.UTC)
+    val untilPart = "UNTIL=%04d%02d%02dT%02d%02d%02dZ".format(
+        until.year, until.month.number, until.day,
+        until.hour, until.minute, until.second,
+    )
+    return (kept + untilPart).joinToString(";")
+}
+
+/**
+ * Date of an RRULE UNTIL value ("20260801" or "20260801T215959Z"). Datetime
+ * forms are UTC (RFC 5545); the date is taken after converting into [zone] so
+ * a [toRRule]-rendered value round-trips to the day the user picked.
+ */
+private fun parseUntilDate(raw: String, zone: TimeZone): LocalDate? = runCatching {
+    val date = LocalDate(
+        raw.substring(0, 4).toInt(),
+        raw.substring(4, 6).toInt(),
+        raw.substring(6, 8).toInt(),
+    )
+    if (raw.length >= 15 && raw[8] == 'T') {
+        val time = LocalTime(
+            raw.substring(9, 11).toInt(),
+            raw.substring(11, 13).toInt(),
+            raw.substring(13, 15).toInt(),
+        )
+        LocalDateTime(date, time).toInstant(TimeZone.UTC).toLocalDateTime(zone).date
+    } else {
+        date
+    }
+}.getOrNull()

app/src/main/java/de/jeanlucmakiola/calendula/domain/contacts/ContactSpecialDate.kt

@@ -0,0 +1,122 @@
+package de.jeanlucmakiola.calendula.domain.contacts
+
+import java.time.LocalDate
+
+/**
+ * The kinds of contact "special date" Calendula mirrors into local calendars.
+ * Each kind gets its own local calendar, so it inherits per-calendar colour,
+ * visibility and reminder defaults for free. See
+ * docs/design/contact-special-dates.md.
+ */
+enum class SpecialDateType {
+    Birthday,
+    Anniversary,
+
+    /** Everything else — a contact "Event" that is neither birthday nor anniversary. */
+    Custom,
+}
+
+/**
+ * One dated event read from a device contact (a `ContactsContract` `Event`
+ * row). The [lookupKey] is the stable contact identity used to reconcile the
+ * mirror without duplicating; [year] is null when the contact stored the date
+ * without one (`--MM-dd`), in which case age can't be shown.
+ */
+data class ContactSpecialDate(
+    val lookupKey: String,
+    val displayName: String,
+    val type: SpecialDateType,
+    val month: Int,
+    val day: Int,
+    val year: Int?,
+    /** The contact's custom label for a [SpecialDateType.Custom] date, if any. */
+    val label: String? = null,
+)
+
+/** The parsed month/day (+ optional year) of a contact date. */
+data class ContactDateParts(val year: Int?, val month: Int, val day: Int)
+
+/**
+ * A fixed leap year to validate and anchor year-less dates against, so that a
+ * `--02-29` birthday is representable (and, once anchored, only recurs in leap
+ * years — matching how the calendar provider expands a yearly Feb-29 series).
+ */
+const val YEARLESS_ANCHOR_YEAR = 1972
+
+/**
+ * Parse a `ContactsContract.CommonDataKinds.Event.START_DATE` value into its
+ * calendar parts, or null if it isn't a usable date. Handles the three shapes
+ * seen in the wild:
+ * - full `yyyy-MM-dd` (year known),
+ * - year-less `--MM-dd` (year null),
+ * - compact `yyyyMMdd`.
+ *
+ * A date that names an impossible day (e.g. `1999-02-29`) is rejected. Pure, so
+ * it's unit-tested without a device.
+ */
+fun parseContactEventDate(raw: String?): ContactDateParts? {
+    val s = raw?.trim().orEmpty()
+    if (s.isEmpty()) return null
+
+    // Year-less: "--MM-dd" or "--MMdd".
+    if (s.startsWith("--")) {
+        val (m, d) = parseMonthDay(s.substring(2)) ?: return null
+        return validated(null, m, d)
+    }
+
+    if (s.contains('-')) {
+        val parts = s.split('-').filter { it.isNotEmpty() }
+        return when (parts.size) {
+            // "yyyy-MM-dd" — but a leading '-' would have dropped the empty
+            // first part, so require the first token to look like a year.
+            3 -> if (s.startsWith('-')) null else validated(
+                year = parts[0].toIntOrNull() ?: return null,
+                month = parts[1].toIntOrNull() ?: return null,
+                day = parts[2].toIntOrNull() ?: return null,
+            )
+            // Year-less "MM-dd" without the "--" prefix.
+            2 -> validated(
+                year = null,
+                month = parts[0].toIntOrNull() ?: return null,
+                day = parts[1].toIntOrNull() ?: return null,
+            )
+            else -> null
+        }
+    }
+
+    // Compact "yyyyMMdd".
+    if (s.length == 8 && s.all { it.isDigit() }) {
+        return validated(
+            year = s.substring(0, 4).toInt(),
+            month = s.substring(4, 6).toInt(),
+            day = s.substring(6, 8).toInt(),
+        )
+    }
+
+    return null
+}
+
+/** "MM-dd" or compact "MMdd". */
+private fun parseMonthDay(rest: String): Pair<Int, Int>? {
+    if (rest.contains('-')) {
+        val p = rest.split('-').filter { it.isNotEmpty() }
+        if (p.size != 2) return null
+        return (p[0].toIntOrNull() ?: return null) to (p[1].toIntOrNull() ?: return null)
+    }
+    if (rest.length == 4 && rest.all { it.isDigit() }) {
+        return rest.substring(0, 2).toInt() to rest.substring(2, 4).toInt()
+    }
+    return null
+}
+
+/**
+ * Confirm month/day form a real calendar date (validated against the actual
+ * year when known, otherwise the leap anchor so `02-29` survives).
+ */
+private fun validated(year: Int?, month: Int, day: Int): ContactDateParts? {
+    if (month !in 1..12 || day !in 1..31) return null
+    val checkYear = year ?: YEARLESS_ANCHOR_YEAR
+    return runCatching { LocalDate.of(checkYear, month, day) }
+        .map { ContactDateParts(year, month, day) }
+        .getOrNull()
+}

app/src/main/java/de/jeanlucmakiola/calendula/domain/contacts/SpecialDateFormatting.kt

@@ -0,0 +1,65 @@
+package de.jeanlucmakiola.calendula.domain.contacts
+
+import kotlinx.datetime.LocalDate
+
+/**
+ * Prefix of every managed-event `UID_2445`. Distinguishes mirror events from
+ * user-created ones (which carry a random `<uuid>@calendula` UID), so the sync
+ * only ever reconciles — and never deletes — events it actually owns.
+ */
+const val MANAGED_UID_PREFIX = "contact-"
+
+/**
+ * The deterministic `Events.UID_2445` that ties a mirrored event to its source
+ * contact date. Stable across syncs (the reconciliation key), namespaced by
+ * type so the same contact's birthday and anniversary never collide, and — when
+ * a [discriminator] is given — by it too, so two Custom dates on one contact
+ * (e.g. "Wedding" and "Graduation") get distinct events instead of clobbering
+ * each other.
+ */
+fun managedEventUid(type: SpecialDateType, lookupKey: String, discriminator: String? = null): String {
+    val disc = discriminator?.takeIf { it.isNotBlank() }?.let { ":$it" }.orEmpty()
+    return "$MANAGED_UID_PREFIX${type.name.lowercase()}:$lookupKey$disc@calendula"
+}
+
+/**
+ * The reconciliation key for this date's mirrored event. Birthdays/anniversaries
+ * are one-per-contact, so they key on the contact alone; a [SpecialDateType.Custom]
+ * date adds a discriminator (its label, else its month-day) so distinct custom
+ * dates on one contact don't collapse into a single event.
+ */
+fun ContactSpecialDate.managedUid(): String =
+    managedEventUid(type, lookupKey, customDiscriminator())
+
+private fun ContactSpecialDate.customDiscriminator(): String? =
+    if (type == SpecialDateType.Custom) {
+        label?.trim()?.lowercase()?.ifBlank { null } ?: "%02d-%02d".format(month, day)
+    } else {
+        null
+    }
+
+/**
+ * The all-day date the recurring `FREQ=YEARLY` series is anchored at: the real
+ * date when the year is known (so age can be derived), otherwise the month/day
+ * on a fixed leap anchor year so a `--02-29` date stays representable and the
+ * anchor never drifts between syncs.
+ */
+fun ContactSpecialDate.anchorDate(): LocalDate =
+    LocalDate(year ?: YEARLESS_ANCHOR_YEAR, month, day)
+
+/**
+ * Render a title [template] for a contact, substituting `{name}` and `{year}`
+ * (the source year — a birthday's birth year or an anniversary's start year;
+ * empty when [year] is null). Unlike an age, the year is static and correct on
+ * every occurrence of the yearly event. Collapses the whitespace an empty
+ * `{year}` may leave behind, so "{name}'s birthday ({year})" degrades cleanly to
+ * "Jane's birthday" when no year is known.
+ */
+fun renderSpecialDateTitle(template: String, name: String, year: Int?): String =
+    template
+        .replace("{name}", name)
+        .replace("{year}", year?.toString().orEmpty())
+        // Drop an empty "()" left by an unresolved {year}, then tidy spacing.
+        .replace(Regex("""\(\s*\)"""), "")
+        .replace(Regex("""\s+"""), " ")
+        .trim()

app/src/main/java/de/jeanlucmakiola/calendula/domain/ics/EventDetailIcs.kt

@@ -0,0 +1,29 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+import de.jeanlucmakiola.calendula.domain.EventDetail
+
+/**
+ * Build the [IcsEvent] for sharing a single event. We export the event the user
+ * is looking at as a **one-off** VEVENT (no RRULE): the detail screen shows one
+ * occurrence, so "share this event" should hand off exactly that instance, not
+ * a whole series anchored to a possibly-different DTSTART. Reminders are the
+ * already-decoded semantic lead times the detail screen holds.
+ */
+fun EventDetail.toShareIcsEvent(): IcsEvent {
+    val startMillis = instance.start.toEpochMilliseconds()
+    return IcsEvent(
+        uid = deriveIcsUid(existingUid = null, eventId = instance.eventId, dtStartMillis = startMillis),
+        summary = instance.title,
+        start = instance.start,
+        end = instance.end,
+        isAllDay = instance.isAllDay,
+        zoneId = eventTimezone?.takeIf { it.isNotBlank() } ?: "UTC",
+        recurrenceRule = null,
+        location = instance.location,
+        description = description,
+        reminderMinutes = reminders.map { it.minutes },
+        status = status,
+        availability = availability,
+        calendarName = null,
+    )
+}

app/src/main/java/de/jeanlucmakiola/calendula/domain/ics/IcsDuration.kt

@@ -0,0 +1,40 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+// Android's calendar provider (and Calendula's own writes) use the non-standard
+// single-unit forms P<n>S / P<n>D / P<n>W — seconds without the RFC-required
+// leading T. Matched first; anything else falls through to the general grammar.
+private val DURATION_SINGLE_UNIT = Regex("""([+-]?)P(\d+)([WDS])""")
+private val DURATION_GENERAL =
+    Regex("""([+-]?)P(?:(\d+)W)?(?:(\d+)D)?(?:T(?:(\d+)H)?(?:(\d+)M)?(?:(\d+)S)?)?""")
+
+/**
+ * Milliseconds of a DURATION (`P1D`, `P3600S`, `PT1H30M`, `-PT15M`, `P1W`, …),
+ * sign-aware. Calendula writes `P<days>D` / `P<seconds>S`, but the parser also
+ * accepts the general RFC 5545 grammar so backup `DURATION` rows and foreign
+ * `VALARM` triggers round-trip. Unparseable input is treated as zero.
+ */
+fun parseRfc2445DurationMillis(duration: String?): Long {
+    if (duration.isNullOrBlank()) return 0L
+    val s = duration.trim()
+
+    DURATION_SINGLE_UNIT.matchEntire(s)?.let { m ->
+        val unitSeconds = when (m.groupValues[3]) {
+            "W" -> 7L * 24 * 60 * 60
+            "D" -> 24L * 60 * 60
+            else -> 1L // S
+        }
+        return m.signum() * m.groupValues[2].toLong() * unitSeconds * 1_000L
+    }
+
+    val m = DURATION_GENERAL.matchEntire(s) ?: return 0L
+    val weeks = m.groupValues[2].toLongOrNull() ?: 0L
+    val days = m.groupValues[3].toLongOrNull() ?: 0L
+    val hours = m.groupValues[4].toLongOrNull() ?: 0L
+    val minutes = m.groupValues[5].toLongOrNull() ?: 0L
+    val seconds = m.groupValues[6].toLongOrNull() ?: 0L
+    val totalSeconds = ((((weeks * 7 + days) * 24 + hours) * 60 + minutes) * 60 + seconds)
+    return m.signum() * totalSeconds * 1_000L
+}
+
+/** Sign carried by group 1 (`-` → -1, otherwise +1) of a duration match. */
+private fun MatchResult.signum(): Long = if (groupValues[1] == "-") -1L else 1L

app/src/main/java/de/jeanlucmakiola/calendula/domain/ics/IcsEvent.kt

@@ -0,0 +1,43 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+import de.jeanlucmakiola.calendula.domain.Availability
+import de.jeanlucmakiola.calendula.domain.EventStatus
+import kotlin.time.Instant
+
+/**
+ * A single event ready to be serialised to a `VEVENT`, decoupled from the
+ * provider so [IcsWriter] stays pure-Kotlin and JVM-testable. [start]/[end] are
+ * absolute instants; [isAllDay] and [recurrenceRule] decide how they are
+ * rendered (see [IcsWriter]'s timezone rule).
+ */
+data class IcsEvent(
+    /** RFC 5545 UID — globally stable across exports (see [deriveIcsUid]). */
+    val uid: String,
+    val summary: String,
+    val start: Instant,
+    /** Exclusive end (for all-day: the next-day midnight, as the provider stores it). */
+    val end: Instant,
+    val isAllDay: Boolean,
+    /** IANA zone id (`Events.EVENT_TIMEZONE`); only used for recurring timed events. */
+    val zoneId: String,
+    /** Bare RRULE value (no `RRULE:` prefix), or null for a one-off event. */
+    val recurrenceRule: String? = null,
+    val location: String? = null,
+    val description: String? = null,
+    /** Reminder lead times in minutes before start (raw provider offsets). */
+    val reminderMinutes: List<Int> = emptyList(),
+    val status: EventStatus = EventStatus.Confirmed,
+    val availability: Availability = Availability.Busy,
+    /** Source calendar name, emitted as `X-CALENDULA-CALENDAR` so a combined backup can fan back out. */
+    val calendarName: String? = null,
+)
+
+/**
+ * The UID to export for a provider event. A row that already carries a UID
+ * (`Events.UID_2445`) keeps it; otherwise we synthesise a **stable** one from
+ * the event id and its DTSTART so the same legacy event yields the same UID
+ * across repeated backups — which keeps a later restore from duplicating it.
+ */
+fun deriveIcsUid(existingUid: String?, eventId: Long, dtStartMillis: Long): String =
+    existingUid?.trim()?.takeIf { it.isNotEmpty() }
+        ?: "$eventId-$dtStartMillis@calendula"

app/src/main/java/de/jeanlucmakiola/calendula/domain/ics/IcsParser.kt

@@ -0,0 +1,259 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+import de.jeanlucmakiola.calendula.domain.Availability
+import de.jeanlucmakiola.calendula.domain.EventStatus
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.atStartOfDayIn
+import kotlinx.datetime.toInstant
+import kotlin.time.Instant
+
+/**
+ * A `VEVENT` parsed from an `.ics` file — the read-side mirror of [IcsEvent],
+ * but [uid] is nullable (an incoming event may carry none; the insert layer
+ * then assigns one). Times are absolute instants; [isAllDay]/[zoneId] mirror
+ * how the writer encoded them.
+ */
+data class ParsedIcsEvent(
+    val uid: String?,
+    val summary: String,
+    val start: Instant,
+    val end: Instant,
+    val isAllDay: Boolean,
+    val zoneId: String,
+    val recurrenceRule: String? = null,
+    val location: String? = null,
+    val description: String? = null,
+    val reminderMinutes: List<Int> = emptyList(),
+    val status: EventStatus = EventStatus.Confirmed,
+    val availability: Availability = Availability.Busy,
+    val calendarName: String? = null,
+)
+
+/** Things the parser dropped rather than failing — surfaced in the import report. */
+enum class IcsParseWarning {
+    /** A `RECURRENCE-ID` override occurrence (not modelled; only masters import). */
+    ModifiedOccurrenceSkipped,
+
+    /** A `VEVENT` with no parseable `DTSTART`. */
+    EventWithoutStartSkipped,
+
+    /** `ATTENDEE` rows were present; Calendula doesn't import attendees. */
+    AttendeesIgnored,
+
+    /** A `TZID` couldn't be resolved against the device tz database (used local zone). */
+    UnknownTimezone,
+}
+
+data class IcsParseResult(
+    val events: List<ParsedIcsEvent>,
+    val warnings: Set<IcsParseWarning>,
+)
+
+/** Outcome of a bulk `.ics` import into one calendar. */
+data class IcsImportSummary(val imported: Int, val skippedDuplicate: Int)
+
+/**
+ * Hand-rolled RFC 5545 reader, the inverse of [IcsWriter]. Pure and
+ * JVM-testable. Liberal-in/strict-out: unknown properties are ignored, a single
+ * malformed `VEVENT` is skipped (not fatal), and unsupported constructs
+ * (`RECURRENCE-ID`, attendees, unresolved `TZID`) are reported as [warnings]
+ * rather than silently dropped. `VTIMEZONE` blocks are skipped — a `TZID` is
+ * resolved against the OS tz database instead ([deviceZone] is the fallback).
+ */
+class IcsParser(private val deviceZone: TimeZone = TimeZone.currentSystemDefault()) {
+
+    fun parse(text: String): IcsParseResult {
+        val lines = unfoldLines(text)
+        val events = mutableListOf<ParsedIcsEvent>()
+        val warnings = mutableSetOf<IcsParseWarning>()
+        var calendarName: String? = null
+
+        var i = 0
+        while (i < lines.size) {
+            val line = parseContentLine(lines[i])
+            if (line == null) { i++; continue }
+            when {
+                line.isBegin("VEVENT") -> {
+                    val end = indexOfEnd(lines, i + 1, "VEVENT")
+                    parseVevent(lines.subList(i + 1, end), calendarName, warnings)
+                        ?.let(events::add)
+                    i = end + 1
+                }
+                line.isBegin("VTIMEZONE") -> {
+                    // Skipped wholesale; TZIDs resolve against the OS tz database.
+                    i = indexOfEnd(lines, i + 1, "VTIMEZONE") + 1
+                }
+                line.name == "X-WR-CALNAME" -> {
+                    calendarName = unescapeText(line.value).trim().ifEmpty { null }
+                    i++
+                }
+                else -> i++
+            }
+        }
+        return IcsParseResult(events, warnings)
+    }
+
+    private fun parseVevent(
+        body: List<String>,
+        fileCalendarName: String?,
+        warnings: MutableSet<IcsParseWarning>,
+    ): ParsedIcsEvent? {
+        var uid: String? = null
+        var summary = ""
+        var dtStart: IcsDateTime? = null
+        var dtEnd: IcsDateTime? = null
+        var duration: String? = null
+        var rrule: String? = null
+        var location: String? = null
+        var description: String? = null
+        var status = EventStatus.Confirmed
+        var availability = Availability.Busy
+        var calendarName = fileCalendarName
+        val reminders = mutableListOf<Int>()
+        var skipAsOverride = false
+
+        var i = 0
+        while (i < body.size) {
+            val line = parseContentLine(body[i])
+            if (line == null) { i++; continue }
+            when (line.name) {
+                "BEGIN" -> if (line.value.trim().equals("VALARM", true)) {
+                    val end = indexOfEnd(body, i + 1, "VALARM")
+                    parseAlarmMinutes(body.subList(i + 1, end))?.let(reminders::add)
+                    i = end + 1
+                    continue
+                }
+                "UID" -> uid = line.value.trim().ifEmpty { null }
+                "SUMMARY" -> summary = unescapeText(line.value)
+                "DTSTART" -> dtStart = parseIcsDateTime(line, warnings)
+                "DTEND" -> dtEnd = parseIcsDateTime(line, warnings)
+                "DURATION" -> duration = line.value.trim()
+                "RRULE" -> rrule = line.value.trim().ifEmpty { null }
+                "LOCATION" -> location = unescapeText(line.value).ifEmpty { null }
+                "DESCRIPTION" -> description = unescapeText(line.value).ifEmpty { null }
+                "STATUS" -> status = mapIcsStatus(line.value)
+                "TRANSP" -> availability =
+                    if (line.value.trim().equals("TRANSPARENT", true)) Availability.Free
+                    else Availability.Busy
+                "RECURRENCE-ID" -> skipAsOverride = true
+                "ATTENDEE" -> warnings.add(IcsParseWarning.AttendeesIgnored)
+                "X-CALENDULA-CALENDAR" ->
+                    calendarName = unescapeText(line.value).trim().ifEmpty { calendarName }
+            }
+            i++
+        }
+
+        if (skipAsOverride) {
+            warnings.add(IcsParseWarning.ModifiedOccurrenceSkipped)
+            return null
+        }
+        val start = dtStart ?: run {
+            warnings.add(IcsParseWarning.EventWithoutStartSkipped)
+            return null
+        }
+        val end = dtEnd
+            ?: duration?.let {
+                start.copy(
+                    instant = Instant.fromEpochMilliseconds(
+                        start.instant.toEpochMilliseconds() + parseRfc2445DurationMillis(it),
+                    ),
+                )
+            }
+            ?: start
+        return ParsedIcsEvent(
+            uid = uid,
+            summary = summary,
+            start = start.instant,
+            end = end.instant,
+            isAllDay = start.isAllDay,
+            zoneId = start.zoneId,
+            recurrenceRule = rrule,
+            location = location,
+            description = description,
+            reminderMinutes = reminders.distinct(),
+            status = status,
+            availability = availability,
+            calendarName = calendarName,
+        )
+    }
+
+    /** A VALARM's lead time in minutes before start, or null if not a usable relative trigger. */
+    private fun parseAlarmMinutes(body: List<String>): Int? {
+        val trigger = body.asSequence()
+            .mapNotNull { parseContentLine(it) }
+            .firstOrNull { it.name == "TRIGGER" }
+            ?: return null
+        // Absolute (DATE-TIME) triggers can't be expressed as a lead time.
+        if (trigger.params["VALUE"].equals("DATE-TIME", true)) return null
+        val millis = parseRfc2445DurationMillis(trigger.value)
+        // Negative = before start (the normal case) → positive lead minutes.
+        return (-millis / 60_000L).toInt().coerceAtLeast(0)
+    }
+
+    private fun parseIcsDateTime(line: IcsContentLine, warnings: MutableSet<IcsParseWarning>): IcsDateTime? {
+        val raw = line.value.trim()
+        val isDate = line.params["VALUE"].equals("DATE", true) ||
+            (raw.length == 8 && !raw.contains('T'))
+        if (isDate) {
+            val date = parseBasicDate(raw) ?: return null
+            return IcsDateTime(date.atStartOfDayIn(TimeZone.UTC), isAllDay = true, zoneId = "UTC")
+        }
+        val isUtc = raw.endsWith("Z")
+        val ldt = parseBasicDateTime(raw.removeSuffix("Z")) ?: return null
+        if (isUtc) return IcsDateTime(ldt.toInstant(TimeZone.UTC), isAllDay = false, zoneId = "UTC")
+
+        val tzid = line.params["TZID"]
+        val resolved = tzid?.let { id -> runCatching { TimeZone.of(id) }.getOrNull()?.let { id to it } }
+        if (tzid != null && resolved == null) warnings.add(IcsParseWarning.UnknownTimezone)
+        val (zoneId, zone) = resolved ?: (deviceZone.id to deviceZone)
+        return IcsDateTime(ldt.toInstant(zone), isAllDay = false, zoneId = zoneId)
+    }
+
+    private data class IcsDateTime(val instant: Instant, val isAllDay: Boolean, val zoneId: String)
+
+    private companion object {
+        fun IcsContentLine.isBegin(component: String) =
+            name == "BEGIN" && value.trim().equals(component, true)
+
+        /** Index of the matching `END:<component>` at/after [from], or list end. */
+        fun indexOfEnd(lines: List<String>, from: Int, component: String): Int {
+            var i = from
+            while (i < lines.size) {
+                val line = parseContentLine(lines[i])
+                if (line != null && line.name == "END" &&
+                    line.value.trim().equals(component, true)
+                ) {
+                    return i
+                }
+                i++
+            }
+            return lines.size
+        }
+
+        fun mapIcsStatus(value: String): EventStatus = when (value.trim().uppercase()) {
+            "TENTATIVE" -> EventStatus.Tentative
+            "CANCELLED" -> EventStatus.Cancelled
+            else -> EventStatus.Confirmed
+        }
+
+        fun parseBasicDate(s: String): LocalDate? = runCatching {
+            LocalDate(s.substring(0, 4).toInt(), s.substring(4, 6).toInt(), s.substring(6, 8).toInt())
+        }.getOrNull()
+
+        fun parseBasicDateTime(s: String): LocalDateTime? = runCatching {
+            val date = LocalDate(
+                s.substring(0, 4).toInt(), s.substring(4, 6).toInt(), s.substring(6, 8).toInt(),
+            )
+            // Format is YYYYMMDD 'T' HHMMSS; seconds optional.
+            val time = LocalTime(
+                s.substring(9, 11).toInt(),
+                s.substring(11, 13).toInt(),
+                if (s.length >= 15) s.substring(13, 15).toInt() else 0,
+            )
+            LocalDateTime(date, time)
+        }.getOrNull()
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/domain/ics/IcsText.kt

@@ -0,0 +1,155 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+/**
+ * Low-level RFC 5545 text mechanics, kept separate from [IcsWriter] so the
+ * escaping and folding rules can be tested in isolation. Pure Kotlin — no
+ * Android, no time handling.
+ */
+
+/** iCalendar mandates CRLF line breaks, not the platform separator. */
+const val ICS_CRLF: String = "\r\n"
+
+/** RFC 5545 §3.1: content lines SHOULD be folded at 75 octets (excluding the break). */
+private const val MAX_OCTETS = 75
+
+/**
+ * Escape a TEXT value (SUMMARY, DESCRIPTION, LOCATION, …) per RFC 5545 §3.3.11:
+ * backslash, semicolon and comma are escaped, newlines become the literal `\n`.
+ * Backslash is handled first so it doesn't double-escape the others' markers.
+ */
+fun escapeText(value: String): String = buildString(value.length) {
+    for (ch in value) {
+        when (ch) {
+            '\\' -> append("\\\\")
+            ';' -> append("\\;")
+            ',' -> append("\\,")
+            '\n' -> append("\\n")
+            '\r' -> Unit // CR is dropped; a lone CRLF in source text folds to one \n
+            else -> append(ch)
+        }
+    }
+}
+
+/**
+ * Fold a single content line to ≤75 octets per physical line, inserting
+ * `CRLF + space` between segments (the space is part of the 75-octet budget of
+ * the continuation line, so its content caps at 74). Folding counts UTF-8
+ * octets, never splitting a multi-byte character across a boundary.
+ */
+fun foldLine(line: String): String {
+    if (line.toByteArray(Charsets.UTF_8).size <= MAX_OCTETS) return line
+    val out = StringBuilder()
+    var octetsThisLine = 0
+    var first = true
+    var i = 0
+    while (i < line.length) {
+        val cp = line.codePointAt(i)
+        val width = Character.charCount(cp)
+        val piece = line.substring(i, i + width)
+        val pieceOctets = piece.toByteArray(Charsets.UTF_8).size
+        // Continuation lines spend one octet on the leading space.
+        val budget = if (first) MAX_OCTETS else MAX_OCTETS - 1
+        if (octetsThisLine + pieceOctets > budget) {
+            out.append(ICS_CRLF).append(' ')
+            octetsThisLine = 0
+            first = false
+        }
+        out.append(piece)
+        octetsThisLine += pieceOctets
+        i += width
+    }
+    return out.toString()
+}
+
+/**
+ * Reverse of [escapeText]: turn `\n`/`\N` into newlines and unescape `\\`, `\;`,
+ * `\,`. A backslash before any other character is dropped, keeping the
+ * character (lenient — foreign files escape liberally).
+ */
+fun unescapeText(value: String): String = buildString(value.length) {
+    var i = 0
+    while (i < value.length) {
+        val c = value[i]
+        if (c == '\\' && i + 1 < value.length) {
+            when (val next = value[i + 1]) {
+                'n', 'N' -> append('\n')
+                else -> append(next) // \\, \;, \, and any other escaped char
+            }
+            i += 2
+        } else {
+            append(c)
+            i++
+        }
+    }
+}
+
+/**
+ * Reverse of [foldLine] across a whole document: split into physical lines on
+ * CRLF/LF/CR, then re-join any line that begins with a single space or tab onto
+ * the previous one (RFC 5545 unfolding). Returns the logical content lines.
+ */
+fun unfoldLines(text: String): List<String> {
+    val out = mutableListOf<String>()
+    for (physical in text.split("\r\n", "\n", "\r")) {
+        if (physical.isEmpty()) continue
+        val isContinuation = physical[0] == ' ' || physical[0] == '\t'
+        if (isContinuation && out.isNotEmpty()) {
+            out[out.lastIndex] = out.last() + physical.substring(1)
+        } else {
+            out.add(physical)
+        }
+    }
+    return out
+}
+
+/**
+ * One unfolded content line split into its property name, parameters and value:
+ * `SUMMARY;LANGUAGE=en:Lunch` → name `SUMMARY`, params `{LANGUAGE=en}`, value
+ * `Lunch`. The value is everything after the first colon that isn't inside a
+ * quoted parameter; param keys are upper-cased, quoted param values unquoted.
+ * Returns null for a line with no colon.
+ */
+data class IcsContentLine(val name: String, val params: Map<String, String>, val value: String)
+
+fun parseContentLine(line: String): IcsContentLine? {
+    var inQuote = false
+    var colon = -1
+    for (i in line.indices) {
+        when (line[i]) {
+            '"' -> inQuote = !inQuote
+            ':' -> if (!inQuote) { colon = i; break }
+        }
+    }
+    if (colon < 0) return null
+    val head = splitUnquoted(line.substring(0, colon), ';')
+    val name = head.firstOrNull()?.trim()?.uppercase().orEmpty()
+    if (name.isEmpty()) return null
+    val params = buildMap {
+        for (part in head.drop(1)) {
+            val eq = part.indexOf('=')
+            if (eq > 0) {
+                put(
+                    part.substring(0, eq).trim().uppercase(),
+                    part.substring(eq + 1).trim().removeSurrounding("\""),
+                )
+            }
+        }
+    }
+    return IcsContentLine(name, params, line.substring(colon + 1))
+}
+
+/** Split on [delimiter] except where it falls inside a double-quoted run. */
+private fun splitUnquoted(text: String, delimiter: Char): List<String> {
+    val parts = mutableListOf<String>()
+    val current = StringBuilder()
+    var inQuote = false
+    for (c in text) {
+        when {
+            c == '"' -> { inQuote = !inQuote; current.append(c) }
+            c == delimiter && !inQuote -> { parts.add(current.toString()); current.clear() }
+            else -> current.append(c)
+        }
+    }
+    parts.add(current.toString())
+    return parts
+}

app/src/main/java/de/jeanlucmakiola/calendula/domain/ics/IcsWriter.kt

@@ -0,0 +1,124 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+import de.jeanlucmakiola.calendula.domain.Availability
+import de.jeanlucmakiola.calendula.domain.EventStatus
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.number
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Instant
+
+/** Default `PRODID` advertising the writer that produced the file. */
+const val ICS_PROD_ID: String = "-//Jean-Luc Makiola//Calendula//EN"
+
+/**
+ * Hand-rolled RFC 5545 serialiser for the subset Calendula models. No iCal
+ * library: we stay on `kotlinx-datetime` and own the output, exactly as
+ * `domain/Recurrence.kt` owns RRULE. Pure and JVM-testable — the caller
+ * supplies [dtStamp] (the export moment) so the writer never reads a clock.
+ *
+ * Timezone rule (see plan 05, decision 1):
+ *  - all-day      → `VALUE=DATE`, no zone;
+ *  - timed one-off → UTC instant with a `Z` suffix (an instant is an instant);
+ *  - timed recurring → `TZID`-labelled local wall time, so the series stays
+ *    anchored to wall-clock across DST. No `VTIMEZONE` block is emitted; import
+ *    resolves the `TZID` against the OS tz database.
+ */
+class IcsWriter(private val prodId: String = ICS_PROD_ID) {
+
+    fun writeCalendar(events: List<IcsEvent>, dtStamp: Instant): String {
+        val lines = buildList {
+            add("BEGIN:VCALENDAR")
+            add("VERSION:2.0")
+            add("PRODID:$prodId")
+            add("CALSCALE:GREGORIAN")
+            events.forEach { appendEvent(it, dtStamp) }
+            add("END:VCALENDAR")
+        }
+        return lines.joinToString(ICS_CRLF, postfix = ICS_CRLF) { foldLine(it) }
+    }
+
+    private fun MutableList<String>.appendEvent(event: IcsEvent, dtStamp: Instant) {
+        add("BEGIN:VEVENT")
+        add("UID:${event.uid}")
+        add("DTSTAMP:${utcStamp(dtStamp)}")
+        add("SUMMARY:${escapeText(event.summary)}")
+        appendTimes(event)
+        event.recurrenceRule?.takeIf { it.isNotBlank() }
+            ?.let { add("RRULE:${it.removePrefix("RRULE:")}") }
+        event.location?.takeIf { it.isNotBlank() }
+            ?.let { add("LOCATION:${escapeText(it)}") }
+        event.description?.takeIf { it.isNotBlank() }
+            ?.let { add("DESCRIPTION:${escapeText(it)}") }
+        add("STATUS:${statusValue(event.status)}")
+        add("TRANSP:${transpValue(event.availability)}")
+        event.calendarName?.takeIf { it.isNotBlank() }
+            ?.let { add("X-CALENDULA-CALENDAR:${escapeText(it)}") }
+        event.reminderMinutes.filter { it >= 0 }.distinct().forEach { minutes ->
+            appendAlarm(minutes, event.summary)
+        }
+        add("END:VEVENT")
+    }
+
+    private fun MutableList<String>.appendTimes(event: IcsEvent) = when {
+        event.isAllDay -> {
+            add("DTSTART;VALUE=DATE:${utcDate(event.start)}")
+            add("DTEND;VALUE=DATE:${utcDate(event.end)}")
+        }
+        // Recurring: anchor to wall-clock in the event's own zone.
+        event.recurrenceRule?.isNotBlank() == true -> {
+            val zone = runCatching { TimeZone.of(event.zoneId) }.getOrNull()
+            if (zone != null) {
+                add("DTSTART;TZID=${event.zoneId}:${localStamp(event.start, zone)}")
+                add("DTEND;TZID=${event.zoneId}:${localStamp(event.end, zone)}")
+            } else {
+                // Unknown zone id → fall back to plain UTC instants.
+                add("DTSTART:${utcStamp(event.start)}")
+                add("DTEND:${utcStamp(event.end)}")
+            }
+        }
+        else -> {
+            add("DTSTART:${utcStamp(event.start)}")
+            add("DTEND:${utcStamp(event.end)}")
+        }
+    }
+
+    private fun MutableList<String>.appendAlarm(minutes: Int, summary: String) {
+        add("BEGIN:VALARM")
+        add("ACTION:DISPLAY")
+        add("DESCRIPTION:${escapeText(summary.ifBlank { "Reminder" })}")
+        add("TRIGGER:${triggerValue(minutes)}")
+        add("END:VALARM")
+    }
+
+    private companion object {
+        fun statusValue(status: EventStatus): String = when (status) {
+            EventStatus.Confirmed -> "CONFIRMED"
+            EventStatus.Tentative -> "TENTATIVE"
+            EventStatus.Cancelled -> "CANCELLED"
+        }
+
+        // iCal TRANSP is binary; only an explicitly free event is TRANSPARENT.
+        fun transpValue(availability: Availability): String =
+            if (availability == Availability.Free) "TRANSPARENT" else "OPAQUE"
+
+        // A lead time of 0 fires at start (PT0M); anything positive is "before".
+        fun triggerValue(minutes: Int): String =
+            if (minutes <= 0) "PT0M" else "-PT${minutes}M"
+
+        fun utcStamp(instant: Instant): String =
+            basic(instant.toLocalDateTime(TimeZone.UTC)) + "Z"
+
+        fun localStamp(instant: Instant, zone: TimeZone): String =
+            basic(instant.toLocalDateTime(zone))
+
+        fun utcDate(instant: Instant): String {
+            val dt = instant.toLocalDateTime(TimeZone.UTC)
+            return "%04d%02d%02d".format(dt.year, dt.month.number, dt.day)
+        }
+
+        fun basic(dt: LocalDateTime): String = "%04d%02d%02dT%02d%02d%02d".format(
+            dt.year, dt.month.number, dt.day, dt.hour, dt.minute, dt.second,
+        )
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/domain/ics/ParsedIcsForm.kt

@@ -0,0 +1,38 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+import de.jeanlucmakiola.calendula.domain.EventForm
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
+
+/**
+ * Prefill the create form from a single parsed `.ics` event (the "open one
+ * event" path). [calendarId] is left null so the form preselects the last-used
+ * calendar, exactly like a fresh create — the user confirms the target and
+ * reviews everything before saving. Mirrors `EventDetail.toEditForm`'s all-day
+ * handling (provider all-day times are UTC midnights with an exclusive end).
+ */
+fun ParsedIcsEvent.toEventForm(zone: TimeZone): EventForm {
+    val (start, end) = if (isAllDay) {
+        val startDate = this.start.toLocalDateTime(TimeZone.UTC).date
+        val endExclusive = this.end.toLocalDateTime(TimeZone.UTC).date
+        val endDate = maxOf(startDate, LocalDate.fromEpochDays(endExclusive.toEpochDays() - 1))
+        LocalDateTime(startDate, LocalTime(9, 0)) to LocalDateTime(endDate, LocalTime(10, 0))
+    } else {
+        this.start.toLocalDateTime(zone) to this.end.toLocalDateTime(zone)
+    }
+    return EventForm(
+        calendarId = null,
+        title = summary,
+        isAllDay = isAllDay,
+        start = start,
+        end = end,
+        location = location.orEmpty(),
+        description = description.orEmpty(),
+        reminders = reminderMinutes.distinct().sorted(),
+        availability = availability,
+        rrule = recurrenceRule?.removePrefix("RRULE:")?.takeIf { it.isNotBlank() },
+    )
+}

app/src/main/java/de/jeanlucmakiola/calendula/qs/NewEventTileService.kt

@@ -0,0 +1,43 @@
+package de.jeanlucmakiola.calendula.qs
+
+import android.app.PendingIntent
+import android.os.Build
+import android.service.quicksettings.TileService
+import de.jeanlucmakiola.calendula.MainActivity
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Clock
+
+/**
+ * Quick Settings tile: tapping it opens the create-event form on today — the
+ * same action as the launcher "New event" shortcut and the agenda widget's "+".
+ * A stateless action tile, so there is no on/off state to keep in sync.
+ */
+class NewEventTileService : TileService() {
+
+    // The pre-34 branch intentionally uses the deprecated Intent overload: it is
+    // the only form available below UpsideDownCake, and is reached only there.
+    @Suppress("DEPRECATION", "StartActivityAndCollapseDeprecated")
+    override fun onClick() {
+        super.onClick()
+        val today = Clock.System.now()
+            .toLocalDateTime(TimeZone.currentSystemDefault()).date
+        val intent = MainActivity.openCreateIntent(this, today)
+        // Launch only once the device is unlocked: creating an event behind the
+        // keyguard makes no sense, and the shade can't start an activity over a
+        // locked screen anyway.
+        unlockAndRun {
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE) {
+                val pending = PendingIntent.getActivity(
+                    this,
+                    0,
+                    intent,
+                    PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT,
+                )
+                startActivityAndCollapse(pending)
+            } else {
+                startActivityAndCollapse(intent)
+            }
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/CalendarHost.kt

@@ -0,0 +1,433 @@
+package de.jeanlucmakiola.calendula.ui
+
+import androidx.activity.compose.BackHandler
+import androidx.compose.animation.AnimatedContent
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.fadeOut
+import androidx.compose.animation.slideInHorizontally
+import androidx.compose.animation.slideOutHorizontally
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.listSaver
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import de.jeanlucmakiola.calendula.domain.EventForm
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.ui.agenda.AgendaScreen
+import de.jeanlucmakiola.calendula.ui.calendars.CalendarsScreen
+import de.jeanlucmakiola.calendula.ui.common.calendarFadeThrough
+import de.jeanlucmakiola.calendula.ui.common.CalendarView
+import de.jeanlucmakiola.calendula.ui.common.drillToDay
+import de.jeanlucmakiola.calendula.ui.common.rememberCalendarSlideSpec
+import de.jeanlucmakiola.calendula.ui.common.selectView
+import de.jeanlucmakiola.calendula.ui.common.viewBaseStack
+import de.jeanlucmakiola.calendula.ui.day.DayScreen
+import de.jeanlucmakiola.calendula.ui.detail.EventDetailScreen
+import de.jeanlucmakiola.calendula.ui.edit.EventEditScreen
+import de.jeanlucmakiola.calendula.ui.imports.ImportScreen
+import de.jeanlucmakiola.calendula.ui.month.MonthScreen
+import de.jeanlucmakiola.calendula.ui.search.SearchScreen
+import de.jeanlucmakiola.calendula.ui.settings.SettingsScreen
+import de.jeanlucmakiola.calendula.ui.week.WeekScreen
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Clock
+
+/**
+ * Holds the top-level view back stack (spec M1) and swaps between the calendar
+ * screens. Each screen owns its own ViewModel and date anchor; the view-switcher
+ * pill in their top bars writes back here via [onSelectView].
+ *
+ * The stack's bottom is the user's [CalendarHostViewModel.defaultView] home view.
+ * A lateral switch (pill / drawer) builds a visit history so back retraces it
+ * (see [selectView]); a widget launch resets the stack to its own view; a date
+ * tap drills the day view on top. Pressing back pops one level, and the
+ * base-level [BackHandler] hands off to the system to exit once only the home
+ * view remains. So back from a widget-opened screen returns to that widget's
+ * view, then home; and back through pill switches walks the views in reverse.
+ *
+ * [requestedDetailKey] is an externally requested occurrence (a tapped
+ * reminder notification routed through MainActivity): it opens the detail
+ * overlay exactly like an event tap and is cleared via [onDetailKeyConsumed]
+ * so a later recomposition can't re-open it. (A widget event tap instead arrives
+ * as [WidgetNavRequest.OpenEvent], which also roots the back stack in the
+ * widget's view.)
+ */
+@Composable
+fun CalendarHost(
+    modifier: Modifier = Modifier,
+    requestedDetailKey: LongArray? = null,
+    onDetailKeyConsumed: () -> Unit = {},
+    widgetNavRequest: WidgetNavRequest? = null,
+    onWidgetNavConsumed: () -> Unit = {},
+    requestedImportUri: android.net.Uri? = null,
+    onImportConsumed: () -> Unit = {},
+    viewModel: CalendarHostViewModel = hiltViewModel(),
+) {
+    // Wait for the persisted default view before seeding the stack, so the app
+    // opens straight on the user's choice instead of flashing a placeholder and
+    // correcting it. Brief blank first frame, matching the onboarding gate above.
+    val defaultView = viewModel.defaultView.collectAsStateWithLifecycle().value ?: return
+
+    // View customisation (#24): the quick-switch cycle and drawer order. Both have
+    // sensible non-empty initial values, so they're ready before the first frame.
+    val quickSwitchViews = viewModel.quickSwitchViews.collectAsStateWithLifecycle().value
+    val drawerViewOrder = viewModel.drawerViewOrder.collectAsStateWithLifecycle().value
+
+    var viewStack by rememberSaveable(stateSaver = viewStackSaver) {
+        mutableStateOf(listOf(defaultView))
+    }
+    val view = viewStack.last()
+    val onSelectView: (CalendarView) -> Unit = { viewStack = viewStack.selectView(it) }
+
+    // Tapping a day in the month grid opens the day view anchored to that date.
+    var pendingDayIso by rememberSaveable { mutableStateOf<String?>(null) }
+    val onOpenDay: (LocalDate) -> Unit = { date ->
+        pendingDayIso = date.toString()
+        viewStack = viewStack.drillToDay()
+    }
+
+    // The event-detail screen (S4) is a full-screen destination hoisted here so
+    // it overlays whichever calendar view is active. We forward the tapped
+    // occurrence's own times (eventId + begin + end, packed as a saveable
+    // long[]) so recurring events show the correct date, not the series start.
+    // [heldKey] keeps the last shown key alive through the slide-out (when
+    // [detailKey] is cleared); it is set in the tap callback — never a [0,0,0]
+    // placeholder — so the destination never loads a bogus id=0 on first frame.
+    var detailKey by rememberSaveable { mutableStateOf<LongArray?>(null) }
+    var heldKey by remember { mutableStateOf<LongArray?>(null) }
+    val onEventClick: (EventInstance) -> Unit = { event ->
+        val key = longArrayOf(
+            event.eventId,
+            event.start.toEpochMilliseconds(),
+            event.end.toEpochMilliseconds(),
+        )
+        heldKey = key
+        detailKey = key
+    }
+
+    // A tapped reminder notification asks for a specific occurrence.
+    LaunchedEffect(requestedDetailKey) {
+        if (requestedDetailKey != null) {
+            heldKey = requestedDetailKey
+            detailKey = requestedDetailKey
+            onDetailKeyConsumed()
+        }
+    }
+
+    // Settings (M4) is hoisted here so it overlays whichever calendar view is
+    // active and survives view switches. (The calendar filter now lives inline
+    // in the navigation drawer, so no overlay state is needed for it.)
+    var showSettings by rememberSaveable { mutableStateOf(false) }
+    val onOpenSettings = { showSettings = true }
+
+    // Full-text search — its own overlay, opened from each calendar screen's
+    // top bar. Sits below the detail/edit overlays so tapping a result reveals
+    // the detail on top and backing out returns to the results.
+    var showSearch by rememberSaveable { mutableStateOf(false) }
+    val onOpenSearch = { showSearch = true }
+
+    // Calendar manager (reached from Settings) — its own overlay so it slides
+    // over Settings and survives view switches.
+    var showCalendars by rememberSaveable { mutableStateOf(false) }
+
+    // Event form (v1.2 create) — same held-key pattern as the detail screen:
+    // [heldCreateIso] keeps the prefill date alive through the slide-out.
+    // [createStartMinutes] is the tapped slot's start (minutes from midnight)
+    // when the form is opened from a day/week grid tap; null from the FAB.
+    var createDateIso by rememberSaveable { mutableStateOf<String?>(null) }
+    var heldCreateIso by remember { mutableStateOf<String?>(null) }
+    var createStartMinutes by rememberSaveable { mutableStateOf<Int?>(null) }
+    var heldCreateMinutes by remember { mutableStateOf<Int?>(null) }
+    val onCreateEvent: (LocalDate, Int?) -> Unit = { date, startMinutes ->
+        heldCreateIso = date.toString()
+        createDateIso = date.toString()
+        heldCreateMinutes = startMinutes
+        createStartMinutes = startMinutes
+    }
+
+    // Edit form (v1.3) — reuses the detail screen's occurrence key; for
+    // recurring events the form itself asks for the write scope at save
+    // time. A saved edit closes the detail screen too: the occurrence the
+    // user tapped may not exist anymore (time moved, recurrence changed), so
+    // falling back to the auto-refreshing calendar is the only honest
+    // destination.
+    var editKey by rememberSaveable { mutableStateOf<LongArray?>(null) }
+    var heldEditKey by remember { mutableStateOf<LongArray?>(null) }
+
+    // An opened/received .ics file. [ImportScreen] parses it and either opens
+    // the prefilled create form (one event → [importForm]) or its own bulk
+    // picker (many). A plain conditional overlay (no slide) — it's transient.
+    var importUri by remember { mutableStateOf<android.net.Uri?>(null) }
+    var importForm by remember { mutableStateOf<EventForm?>(null) }
+    LaunchedEffect(requestedImportUri) {
+        if (requestedImportUri != null) {
+            importUri = requestedImportUri
+            onImportConsumed()
+        }
+    }
+
+    // Close every overlay that can sit over the calendar, so an externally
+    // requested destination (a widget/shortcut/QS-tile launch) is revealed on
+    // top instead of underneath whatever the user had open.
+    fun dismissCoveringOverlays() {
+        showSettings = false
+        showCalendars = false
+        detailKey = null
+        editKey = null
+        importUri = null
+        importForm = null
+    }
+
+    // A home-screen widget launch asks to open a date (→ day view), open an
+    // event's detail, or start a create. Handled once and cleared, mirroring
+    // [requestedDetailKey]. Date/event opens root the stack in the widget's own
+    // view so backing out returns there (then home), not to the default.
+    LaunchedEffect(widgetNavRequest) {
+        when (val req = widgetNavRequest) {
+            is WidgetNavRequest.OpenDate -> {
+                // Drill the day view in over the widget's view: drop any overlay
+                // that would cover it, so the open doesn't land under Settings/form.
+                dismissCoveringOverlays()
+                createDateIso = null
+                pendingDayIso = req.dateIso
+                // No widget source (an external date tap) roots over the default
+                // home view, so backing out of the day returns home then exits.
+                viewStack = viewBaseStack(defaultView, req.source ?: defaultView).drillToDay()
+                onWidgetNavConsumed()
+            }
+            is WidgetNavRequest.OpenEvent -> {
+                // Root the stack in the widget's view, then open the occurrence
+                // detail over it (same key shape as a tapped event / reminder).
+                dismissCoveringOverlays()
+                createDateIso = null
+                viewStack = viewBaseStack(defaultView, req.source)
+                val key = longArrayOf(req.eventId, req.beginMillis, req.endMillis)
+                heldKey = key
+                detailKey = key
+                onWidgetNavConsumed()
+            }
+            is WidgetNavRequest.OpenView -> {
+                // A widget header tap: land on a top-level view with no date
+                // drill-in. Reveal it by dropping any covering overlay, then root
+                // the stack on the target (null → the default home) over the
+                // default home — so backing out returns to the default, then exits.
+                dismissCoveringOverlays()
+                createDateIso = null
+                pendingDayIso = null
+                viewStack = viewBaseStack(defaultView, req.view ?: defaultView)
+                onWidgetNavConsumed()
+            }
+            is WidgetNavRequest.Create -> {
+                // External "new event" entries (QS tile / launcher shortcut /
+                // widget) must land on top of whatever is open — the form overlay
+                // sits below Settings/calendars in the Box, so without this it
+                // would open hidden underneath them.
+                dismissCoveringOverlays()
+                val iso = req.dateIso ?: Clock.System.now()
+                    .toLocalDateTime(TimeZone.currentSystemDefault()).date.toString()
+                heldCreateIso = iso
+                createDateIso = iso
+                heldCreateMinutes = null
+                createStartMinutes = null
+                onWidgetNavConsumed()
+            }
+            null -> {}
+        }
+    }
+
+    val slideSpec = rememberCalendarSlideSpec()
+
+    // Base-level back: pop the view stack while no overlay covers it (each overlay
+    // owns its own BackHandler and takes precedence). Disabled at the home view,
+    // so back there falls through to the system and exits the app.
+    val anyOverlayVisible = showSearch || detailKey != null || createDateIso != null ||
+        editKey != null || showSettings || showCalendars || importUri != null ||
+        importForm != null
+    BackHandler(enabled = !anyOverlayVisible && viewStack.size > 1) {
+        viewStack = viewStack.dropLast(1)
+    }
+
+    Box(modifier = modifier.fillMaxSize()) {
+        // Switching between the peer views (month/week/day/agenda) is lateral
+        // navigation, so it fades through rather than sliding — paging *within* a
+        // view keeps the directional slide. AnimatedContent keyed on the view type.
+        val viewSwitch = calendarFadeThrough()
+        AnimatedContent(
+            targetState = view,
+            transitionSpec = { viewSwitch },
+            label = "view-switch",
+        ) { currentView ->
+            when (currentView) {
+                CalendarView.Week -> WeekScreen(
+                    selectedView = currentView,
+                    onSelectView = onSelectView,
+                    onEventClick = onEventClick,
+                    onOpenSettings = onOpenSettings,
+                    onOpenSearch = onOpenSearch,
+                    onCreateEvent = onCreateEvent,
+                    quickSwitchViews = quickSwitchViews,
+                    drawerViewOrder = drawerViewOrder,
+                )
+                CalendarView.Day -> DayScreen(
+                    selectedView = currentView,
+                    onSelectView = onSelectView,
+                    onEventClick = onEventClick,
+                    onOpenSettings = onOpenSettings,
+                    onOpenSearch = onOpenSearch,
+                    onCreateEvent = onCreateEvent,
+                    initialDateIso = pendingDayIso,
+                    quickSwitchViews = quickSwitchViews,
+                    drawerViewOrder = drawerViewOrder,
+                )
+                CalendarView.Month -> MonthScreen(
+                    selectedView = currentView,
+                    onSelectView = onSelectView,
+                    onOpenDay = onOpenDay,
+                    onOpenSettings = onOpenSettings,
+                    onOpenSearch = onOpenSearch,
+                    onCreateEvent = onCreateEvent,
+                    quickSwitchViews = quickSwitchViews,
+                    drawerViewOrder = drawerViewOrder,
+                )
+                CalendarView.Agenda -> AgendaScreen(
+                    selectedView = currentView,
+                    onSelectView = onSelectView,
+                    onEventClick = onEventClick,
+                    onOpenSettings = onOpenSettings,
+                    onOpenSearch = onOpenSearch,
+                    onCreateEvent = onCreateEvent,
+                    quickSwitchViews = quickSwitchViews,
+                    drawerViewOrder = drawerViewOrder,
+                )
+            }
+        }
+
+        // Search overlay — below detail/edit in the Box so a tapped result's
+        // detail screen draws on top, and closing it returns to the results.
+        AnimatedVisibility(
+            visible = showSearch,
+            enter = slideInHorizontally(slideSpec) { it } + fadeIn(),
+            exit = slideOutHorizontally(slideSpec) { it } + fadeOut(),
+        ) {
+            SearchScreen(
+                onBack = { showSearch = false },
+                onEventClick = onEventClick,
+            )
+        }
+
+        // Prefer the live key; fall back to the held one only while sliding out.
+        val activeKey = detailKey ?: heldKey
+        AnimatedVisibility(
+            visible = detailKey != null,
+            enter = slideInHorizontally(slideSpec) { it } + fadeIn(),
+            exit = slideOutHorizontally(slideSpec) { it } + fadeOut(),
+        ) {
+            activeKey?.let { key ->
+                EventDetailScreen(
+                    eventId = key[0],
+                    beginMillis = key[1],
+                    endMillis = key[2],
+                    onBack = { detailKey = null },
+                    onEdit = {
+                        heldEditKey = key
+                        editKey = key
+                    },
+                )
+            }
+        }
+
+        // Event form (v1.2) — full-screen destination, slides over the calendar.
+        AnimatedVisibility(
+            visible = createDateIso != null,
+            enter = slideInHorizontally(slideSpec) { it } + fadeIn(),
+            exit = slideOutHorizontally(slideSpec) { it } + fadeOut(),
+        ) {
+            (createDateIso ?: heldCreateIso)?.let { iso ->
+                EventEditScreen(
+                    initialDateIso = iso,
+                    initialStartMinutes = createStartMinutes ?: heldCreateMinutes,
+                    onClose = { createDateIso = null },
+                    onSaved = { createDateIso = null },
+                )
+            }
+        }
+
+        // Edit form (v1.3) — slides over the detail screen.
+        AnimatedVisibility(
+            visible = editKey != null,
+            enter = slideInHorizontally(slideSpec) { it } + fadeIn(),
+            exit = slideOutHorizontally(slideSpec) { it } + fadeOut(),
+        ) {
+            (editKey ?: heldEditKey)?.let { key ->
+                EventEditScreen(
+                    initialDateIso = null,
+                    editKey = key,
+                    onClose = { editKey = null },
+                    onSaved = {
+                        editKey = null
+                        detailKey = null
+                    },
+                )
+            }
+        }
+
+        // Settings (M4) — full-screen destination, slides over the calendar.
+        AnimatedVisibility(
+            visible = showSettings,
+            enter = slideInHorizontally(slideSpec) { it } + fadeIn(),
+            exit = slideOutHorizontally(slideSpec) { it } + fadeOut(),
+        ) {
+            SettingsScreen(
+                onBack = { showSettings = false },
+                onManageCalendars = { showCalendars = true },
+            )
+        }
+
+        // Calendar manager — slides over Settings.
+        AnimatedVisibility(
+            visible = showCalendars,
+            enter = slideInHorizontally(slideSpec) { it } + fadeIn(),
+            exit = slideOutHorizontally(slideSpec) { it } + fadeOut(),
+        ) {
+            CalendarsScreen(onBack = { showCalendars = false })
+        }
+
+        // Import flow for an opened/received .ics file. A single event routes
+        // into the create form (prefilled, for review); many open the picker.
+        importUri?.let { uri ->
+            ImportScreen(
+                uri = uri,
+                onClose = { importUri = null },
+                onOpenSingle = { form ->
+                    importUri = null
+                    importForm = form
+                },
+            )
+        }
+        importForm?.let { form ->
+            EventEditScreen(
+                initialDateIso = null,
+                initialForm = form,
+                onClose = { importForm = null },
+                onSaved = { importForm = null },
+            )
+        }
+    }
+}
+
+/** Persists the view back stack across config change / process death by ordinal. */
+private val viewStackSaver = listSaver<List<CalendarView>, Int>(
+    save = { stack -> stack.map(CalendarView::ordinal) },
+    restore = { ordinals -> ordinals.map { CalendarView.entries[it] } },
+)

app/src/main/java/de/jeanlucmakiola/calendula/ui/CalendarHostViewModel.kt

@@ -0,0 +1,48 @@
+package de.jeanlucmakiola.calendula.ui
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import dagger.hilt.android.lifecycle.HiltViewModel
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import de.jeanlucmakiola.calendula.ui.common.CalendarView
+import de.jeanlucmakiola.calendula.ui.common.IMPLEMENTED_VIEWS
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.stateIn
+import javax.inject.Inject
+
+/**
+ * Supplies [CalendarHost] with the user's default startup view (M1). Held as a
+ * nullable [StateFlow] so the host can wait for DataStore's first emission before
+ * seeding its view back stack — rendering nothing for that first frame rather
+ * than flashing the old hard-coded Week view and then correcting it.
+ */
+@HiltViewModel
+class CalendarHostViewModel @Inject constructor(
+    prefs: SettingsPrefs,
+) : ViewModel() {
+
+    val defaultView: StateFlow<CalendarView?> = prefs.defaultView.stateIn(
+        scope = viewModelScope,
+        started = SharingStarted.WhileSubscribed(5_000L),
+        initialValue = null,
+    )
+
+    /** Views the top-bar quick-switch pill cycles through, in the user's order (#24). */
+    val quickSwitchViews: StateFlow<List<CalendarView>> = prefs.quickSwitchConfig
+        .map { it.cycle }
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5_000L),
+            initialValue = IMPLEMENTED_VIEWS,
+        )
+
+    /** Order of the views in the navigation drawer (#24); every view always shown. */
+    val drawerViewOrder: StateFlow<List<CalendarView>> = prefs.drawerViewOrder
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5_000L),
+            initialValue = IMPLEMENTED_VIEWS,
+        )
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/RootScreen.kt

@@ -2,25 +2,40 @@ package de.jeanlucmakiola.calendula.ui
 
 import android.Manifest
 import android.content.pm.PackageManager
-import androidx.compose.foundation.layout.padding
-import androidx.compose.material3.Scaffold
+import androidx.compose.animation.Crossfade
+import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
+import androidx.compose.material3.MaterialTheme
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.DisposableEffect
-import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
+import androidx.compose.runtime.getValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
+import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.LocalLifecycleOwner
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.core.content.ContextCompat
 import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.LifecycleEventObserver
-import de.jeanlucmakiola.calendula.ui.debug.DebugScreen
+import de.jeanlucmakiola.calendula.data.contacts.SpecialDatesScheduler
+import de.jeanlucmakiola.calendula.data.contacts.hasContactsPermission
 import de.jeanlucmakiola.calendula.ui.permission.PermissionScreen
+import de.jeanlucmakiola.calendula.ui.permission.ReminderOnboardingScreen
+import de.jeanlucmakiola.calendula.ui.permission.ReminderOnboardingViewModel
 
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
 @Composable
-fun RootScreen(modifier: Modifier = Modifier) {
+fun RootScreen(
+    modifier: Modifier = Modifier,
+    requestedDetailKey: LongArray? = null,
+    onDetailKeyConsumed: () -> Unit = {},
+    widgetNavRequest: WidgetNavRequest? = null,
+    onWidgetNavConsumed: () -> Unit = {},
+    requestedImportUri: android.net.Uri? = null,
+    onImportConsumed: () -> Unit = {},
+) {
     val context = LocalContext.current
     var hasPermission by remember {
         mutableStateOf(
@@ -36,19 +51,51 @@ fun RootScreen(modifier: Modifier = Modifier) {
                 hasPermission = ContextCompat.checkSelfPermission(
                     context, Manifest.permission.READ_CALENDAR
                 ) == PackageManager.PERMISSION_GRANTED
+                // Refresh the contact special-dates mirror on foreground (the
+                // worker is debounced and no-ops when the feature is off). Gated
+                // on the permission so users without the opt-in never enqueue it.
+                if (context.hasContactsPermission()) {
+                    SpecialDatesScheduler.runNow(context, foreground = true)
+                }
             }
         }
         lifecycle.addObserver(obs)
         onDispose { lifecycle.removeObserver(obs) }
     }
 
-    Scaffold(modifier = modifier) { innerPadding ->
-        if (hasPermission) {
-            DebugScreen(modifier = Modifier.padding(innerPadding))
+    // Cross-fade the one-time onboarding gates so granting permission / finishing
+    // onboarding eases into the next screen instead of snapping. A fade carries no
+    // spatial motion, so it stays appropriate under "remove animations" too.
+    val gateSpec = MaterialTheme.motionScheme.fastEffectsSpec<Float>()
+    Crossfade(targetState = hasPermission, animationSpec = gateSpec, label = "permissionGate") { granted ->
+        if (granted) {
+            // Second onboarding gate (v1.4, one-time): reminder notifications.
+            // Null until DataStore's first emission — render nothing for that
+            // frame instead of flashing the wrong screen.
+            val reminderOnboarding: ReminderOnboardingViewModel = hiltViewModel()
+            val onboardingDone by reminderOnboarding.onboardingDone.collectAsStateWithLifecycle()
+            Crossfade(targetState = onboardingDone, animationSpec = gateSpec, label = "onboardingGate") { done ->
+                when (done) {
+                    true -> CalendarHost(
+                        modifier = modifier,
+                        requestedDetailKey = requestedDetailKey,
+                        onDetailKeyConsumed = onDetailKeyConsumed,
+                        widgetNavRequest = widgetNavRequest,
+                        onWidgetNavConsumed = onWidgetNavConsumed,
+                        requestedImportUri = requestedImportUri,
+                        onImportConsumed = onImportConsumed,
+                    )
+                    false -> ReminderOnboardingScreen(
+                        onFinished = reminderOnboarding::finish,
+                        modifier = modifier,
+                    )
+                    null -> {}
+                }
+            }
         } else {
             PermissionScreen(
                 onGranted = { hasPermission = true },
-                modifier = Modifier.padding(innerPadding),
+                modifier = modifier,
             )
         }
     }

app/src/main/java/de/jeanlucmakiola/calendula/ui/WidgetNavRequest.kt

@@ -0,0 +1,43 @@
+package de.jeanlucmakiola.calendula.ui
+
+import de.jeanlucmakiola.calendula.ui.common.CalendarView
+
+/**
+ * A navigation a home-screen widget asked the app to perform when launched.
+ * Parsed from the launch intent in MainActivity and consumed once by
+ * [CalendarHost]. Every request carries the [source] view of the widget it came
+ * from (the agenda widget → [CalendarView.Agenda], the month widget →
+ * [CalendarView.Month]) so the in-app back stack roots itself in that view:
+ * backing out of the opened date/event returns to the widget's own view, not the
+ * default home. (Reminder notifications are not widgets — they keep the separate
+ * detail-key channel and leave the base view untouched.)
+ */
+sealed interface WidgetNavRequest {
+    /**
+     * Open the day view anchored on [dateIso] (an ISO `yyyy-MM-dd` date), over
+     * [source]. A null [source] means the request came from outside the app (a
+     * launcher/clock date tap, issue #9) rather than a widget, so it roots over
+     * the default home view instead of a widget's view.
+     */
+    data class OpenDate(val dateIso: String, val source: CalendarView?) : WidgetNavRequest
+
+    /** Open one occurrence's detail (an agenda-widget event tap), over [source]. */
+    data class OpenEvent(
+        val eventId: Long,
+        val beginMillis: Long,
+        val endMillis: Long,
+        val source: CalendarView,
+    ) : WidgetNavRequest
+
+    /** Open the create-event form prefilled for [dateIso] (today when null). */
+    data class Create(val dateIso: String?) : WidgetNavRequest
+
+    /**
+     * Open the app rooted on a top-level [view] with no date drill-in — a widget
+     * header tap. A null [view] means "the user's default home view" (the agenda
+     * widget's "Upcoming" title, issue #20); a concrete view roots there over the
+     * default home (the month widget's month/year title → [CalendarView.Month],
+     * issue #18), so backing out returns to the default view, then exits.
+     */
+    data class OpenView(val view: CalendarView?) : WidgetNavRequest
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/agenda/AgendaRange.kt

@@ -0,0 +1,111 @@
+package de.jeanlucmakiola.calendula.ui.agenda
+
+import kotlinx.datetime.DayOfWeek
+import kotlinx.datetime.LocalDate
+import java.time.YearMonth
+import java.time.format.DateTimeFormatter
+import java.time.format.FormatStyle
+import java.util.Locale
+
+/**
+ * How far ahead the agenda (screen or widget) shows events, starting at today.
+ *
+ * Two flavours:
+ * - **Rolling** windows of a fixed length: [Day] (today), [Week] (7 days),
+ *   [Month] (30 days), [Custom] (1–365 days). These never degenerate.
+ * - **Calendar-aligned** windows that end at a period boundary: [ThisWeek] runs
+ *   through the end of the current week (respecting the week-start preference —
+ *   a Monday start means "everything before next Monday"); [ThisMonth] runs
+ *   through the last day of the current month. These shrink as the period ends.
+ */
+sealed interface AgendaRange {
+    data object Day : AgendaRange
+    data object Week : AgendaRange
+    data object Month : AgendaRange
+    data object ThisWeek : AgendaRange
+    data object ThisMonth : AgendaRange
+    data class Custom(val days: Int) : AgendaRange
+
+    companion object {
+        /** Allowed bounds for a [Custom] day count. */
+        const val MIN_CUSTOM_DAYS = 1
+        const val MAX_CUSTOM_DAYS = 365
+    }
+}
+
+private const val DAYS_PER_WEEK = 7
+
+/**
+ * Inclusive number of days the window spans, starting at (and including)
+ * [anchor]. The calendar-aligned ranges depend on the anchor day and, for
+ * [AgendaRange.ThisWeek], the [weekStart] preference.
+ */
+fun AgendaRange.dayCount(anchor: LocalDate, weekStart: DayOfWeek): Int = when (this) {
+    AgendaRange.Day -> 1
+    AgendaRange.Week -> DAYS_PER_WEEK
+    AgendaRange.Month -> 30
+    AgendaRange.ThisWeek -> {
+        // Days elapsed since the week's first day (0 when today *is* the start),
+        // so the window is the rest of the week through the day before it repeats.
+        val sinceWeekStart = ((anchor.dayOfWeek.ordinal - weekStart.ordinal) + DAYS_PER_WEEK) % DAYS_PER_WEEK
+        DAYS_PER_WEEK - sinceWeekStart
+    }
+    AgendaRange.ThisMonth -> {
+        val daysInMonth = YearMonth.of(anchor.year, anchor.month.ordinal + 1).lengthOfMonth()
+        daysInMonth - anchor.day + 1
+    }
+    is AgendaRange.Custom -> days.coerceIn(AgendaRange.MIN_CUSTOM_DAYS, AgendaRange.MAX_CUSTOM_DAYS)
+}
+
+/** Stored representation: a fixed token, or `CUSTOM:<days>`. */
+fun AgendaRange.storageValue(): String = when (this) {
+    AgendaRange.Day -> "DAY"
+    AgendaRange.Week -> "WEEK"
+    AgendaRange.Month -> "MONTH"
+    AgendaRange.ThisWeek -> "THIS_WEEK"
+    AgendaRange.ThisMonth -> "THIS_MONTH"
+    is AgendaRange.Custom -> "$CUSTOM_PREFIX$days"
+}
+
+/** Parse a stored value; unknown/garbage falls back to [default]. */
+fun parseAgendaRange(stored: String?, default: AgendaRange): AgendaRange = when {
+    stored == "DAY" -> AgendaRange.Day
+    stored == "WEEK" -> AgendaRange.Week
+    stored == "MONTH" -> AgendaRange.Month
+    stored == "THIS_WEEK" -> AgendaRange.ThisWeek
+    stored == "THIS_MONTH" -> AgendaRange.ThisMonth
+    stored != null && stored.startsWith(CUSTOM_PREFIX) -> {
+        val days = stored.removePrefix(CUSTOM_PREFIX).toIntOrNull()
+        if (days != null) {
+            AgendaRange.Custom(days.coerceIn(AgendaRange.MIN_CUSTOM_DAYS, AgendaRange.MAX_CUSTOM_DAYS))
+        } else {
+            default
+        }
+    }
+    else -> default
+}
+
+/**
+ * The concrete span the range covers, starting at [start] through [end]
+ * (inclusive), for a human-readable header:
+ * - [AgendaRange.Day] → a single medium date ("27 Jun 2026")
+ * - [AgendaRange.ThisMonth] → month and year ("June 2026")
+ * - everything else → "start – end" ("27 Jun – 3 Jul 2026")
+ */
+fun agendaRangeWindowSummary(
+    range: AgendaRange,
+    start: LocalDate,
+    end: LocalDate,
+    locale: Locale,
+): String {
+    val javaStart = java.time.LocalDate.of(start.year, start.month.ordinal + 1, start.day)
+    val javaEnd = java.time.LocalDate.of(end.year, end.month.ordinal + 1, end.day)
+    val medium = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM).withLocale(locale)
+    return when (range) {
+        AgendaRange.Day -> medium.format(javaStart)
+        AgendaRange.ThisMonth -> DateTimeFormatter.ofPattern("LLLL yyyy", locale).format(javaStart)
+        else -> "${DateTimeFormatter.ofPattern("d MMM", locale).format(javaStart)} – ${medium.format(javaEnd)}"
+    }
+}
+
+private const val CUSTOM_PREFIX = "CUSTOM:"

app/src/main/java/de/jeanlucmakiola/calendula/ui/agenda/AgendaScreen.kt

@@ -0,0 +1,515 @@
+package de.jeanlucmakiola.calendula.ui.agenda
+
+import androidx.compose.foundation.ExperimentalFoundationApi
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.itemsIndexed
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Coffee
+import androidx.compose.material.icons.filled.DateRange
+import androidx.compose.material.icons.filled.Menu
+import androidx.compose.material.icons.filled.Search
+import androidx.compose.material3.DrawerValue
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.ModalNavigationDrawer
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TopAppBar
+import androidx.compose.material3.TopAppBarDefaults
+import androidx.compose.material3.TopAppBarScrollBehavior
+import androidx.compose.material3.rememberDrawerState
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.alpha
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.input.nestedscroll.nestedScroll
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.data.prefs.PastEventDisplay
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.domain.hasEnded
+import de.jeanlucmakiola.calendula.ui.common.AgendaRangePicker
+import de.jeanlucmakiola.calendula.ui.common.agendaRangeLabel
+import de.jeanlucmakiola.calendula.ui.common.calendarAnimateItem
+import de.jeanlucmakiola.calendula.ui.common.CalendarDrawer
+import de.jeanlucmakiola.calendula.ui.common.CalendarFabColumn
+import de.jeanlucmakiola.calendula.ui.common.CalendarFailure
+import de.jeanlucmakiola.calendula.ui.common.CalendarView
+import de.jeanlucmakiola.calendula.ui.common.IMPLEMENTED_VIEWS
+import de.jeanlucmakiola.calendula.ui.common.EventDimAlpha
+import de.jeanlucmakiola.calendula.ui.common.GroupedRow
+import de.jeanlucmakiola.calendula.ui.common.Position
+import de.jeanlucmakiola.calendula.ui.common.ViewSwitcherPill
+import de.jeanlucmakiola.calendula.ui.common.next
+import de.jeanlucmakiola.calendula.ui.common.pastelize
+import de.jeanlucmakiola.calendula.ui.common.positionOf
+import de.jeanlucmakiola.calendula.ui.common.rememberCurrentMinute
+import de.jeanlucmakiola.calendula.ui.common.currentLocale
+import de.jeanlucmakiola.calendula.ui.common.LocalUse24HourFormat
+import de.jeanlucmakiola.calendula.ui.common.formatTimeOfDay
+import kotlinx.coroutines.launch
+import kotlinx.datetime.DateTimeUnit
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.plus
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Instant
+import java.time.format.TextStyle as JavaTextStyle
+import java.util.Locale
+
+private val zone = TimeZone.currentSystemDefault()
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun AgendaScreen(
+    selectedView: CalendarView,
+    onSelectView: (CalendarView) -> Unit,
+    onEventClick: (EventInstance) -> Unit,
+    onOpenSettings: () -> Unit,
+    onOpenSearch: () -> Unit,
+    onCreateEvent: (LocalDate, Int?) -> Unit,
+    quickSwitchViews: List<CalendarView> = IMPLEMENTED_VIEWS,
+    drawerViewOrder: List<CalendarView> = IMPLEMENTED_VIEWS,
+    modifier: Modifier = Modifier,
+    viewModel: AgendaViewModel = hiltViewModel(),
+) {
+    val state by viewModel.state.collectAsStateWithLifecycle()
+    val anchor by viewModel.anchor.collectAsStateWithLifecycle()
+    val pastDisplay by viewModel.pastEventDisplay.collectAsStateWithLifecycle()
+
+    val scrollBehavior = TopAppBarDefaults.pinnedScrollBehavior()
+    val drawerState = rememberDrawerState(DrawerValue.Closed)
+    val scope = rememberCoroutineScope()
+    var showRangePicker by remember { mutableStateOf(false) }
+
+    val isOnToday = when (val s = state) {
+        is AgendaUiState.Success -> s.anchor == s.today
+        else -> true
+    }
+    val successState = state as? AgendaUiState.Success
+
+    ModalNavigationDrawer(
+        drawerState = drawerState,
+        drawerContent = {
+            CalendarDrawer(
+                currentView = selectedView,
+                currentDate = anchor,
+                viewOrder = drawerViewOrder,
+                onSelectView = { view ->
+                    onSelectView(view)
+                    scope.launch { drawerState.close() }
+                },
+                onJumpToDate = { target ->
+                    viewModel.goToDate(target)
+                    scope.launch { drawerState.close() }
+                },
+                onSettings = {
+                    onOpenSettings()
+                    scope.launch { drawerState.close() }
+                },
+            )
+        },
+    ) {
+        Scaffold(
+            modifier = modifier.nestedScroll(scrollBehavior.nestedScrollConnection),
+            topBar = {
+                AgendaTopBar(
+                    selectedView = selectedView,
+                    onCycleView = { onSelectView(selectedView.next(quickSwitchViews)) },
+                    onOpenDrawer = { scope.launch { drawerState.open() } },
+                    onOpenSearch = onOpenSearch,
+                    scrollBehavior = scrollBehavior,
+                )
+            },
+            floatingActionButton = {
+                CalendarFabColumn(
+                    todayVisible = !isOnToday,
+                    todayText = stringResource(R.string.agenda_today_action),
+                    onToday = viewModel::goToToday,
+                    onCreate = { onCreateEvent(anchor, null) },
+                )
+            },
+        ) { innerPadding ->
+            Column(
+                modifier = Modifier
+                    .fillMaxSize()
+                    .padding(innerPadding),
+            ) {
+                // One bar at the top: the "showing …" header on the left and the
+                // session range switcher on the right (one settings toggle).
+                successState?.takeIf { it.showRangeBar }?.let { s ->
+                    Row(
+                        verticalAlignment = Alignment.CenterVertically,
+                        modifier = Modifier
+                            .fillMaxWidth()
+                            .padding(start = 28.dp, end = 16.dp, top = 8.dp, bottom = 8.dp),
+                    ) {
+                        AgendaRangeBanner(
+                            range = s.range,
+                            start = s.anchor,
+                            end = s.rangeEnd,
+                            modifier = Modifier.weight(1f),
+                        )
+                        AgendaRangePill(
+                            range = s.range,
+                            isOverride = s.rangeIsOverride,
+                            onClick = { showRangePicker = true },
+                        )
+                    }
+                }
+                AgendaContent(
+                    state = state,
+                    pastDisplay = pastDisplay,
+                    onRetry = viewModel::goToToday,
+                    onEventClick = onEventClick,
+                    modifier = Modifier
+                        .weight(1f)
+                        .fillMaxWidth(),
+                )
+            }
+        }
+    }
+
+    if (showRangePicker) {
+        AgendaRangePicker(
+            title = stringResource(R.string.settings_agenda_range),
+            description = stringResource(R.string.agenda_range_override_hint),
+            selected = successState?.range ?: AgendaRange.Month,
+            onSelect = viewModel::setRangeOverride,
+            onDismiss = { showRangePicker = false },
+        )
+    }
+}
+
+/**
+ * A compact tonal pill showing the agenda's current range. Tapping it opens the
+ * range picker as a session-only override. Filled with the primary container
+ * while an override is active, so the temporary state is obvious.
+ */
+@Composable
+private fun AgendaRangePill(
+    range: AgendaRange,
+    isOverride: Boolean,
+    onClick: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    val container = if (isOverride) {
+        MaterialTheme.colorScheme.primaryContainer
+    } else {
+        MaterialTheme.colorScheme.surfaceContainerHigh
+    }
+    val content = if (isOverride) {
+        MaterialTheme.colorScheme.onPrimaryContainer
+    } else {
+        MaterialTheme.colorScheme.onSurfaceVariant
+    }
+    Surface(
+        color = container,
+        contentColor = content,
+        shape = RoundedCornerShape(50),
+        modifier = modifier.clickable(onClick = onClick),
+    ) {
+        Row(
+            verticalAlignment = Alignment.CenterVertically,
+            modifier = Modifier.padding(horizontal = 16.dp, vertical = 10.dp),
+        ) {
+            Icon(
+                imageVector = Icons.Filled.DateRange,
+                contentDescription = null,
+                modifier = Modifier.size(18.dp),
+            )
+            Spacer(Modifier.width(8.dp))
+            Text(
+                text = agendaRangeLabel(range),
+                style = MaterialTheme.typography.labelLarge,
+            )
+        }
+    }
+}
+
+/**
+ * A header naming the concrete window currently shown, e.g. "Showing all events
+ * for · Today, 27 Jun 2026" / "This week, 27 Jun – 3 Jul" / "This month, June 2026".
+ */
+@Composable
+private fun AgendaRangeBanner(
+    range: AgendaRange,
+    start: LocalDate,
+    end: LocalDate,
+    modifier: Modifier = Modifier,
+) {
+    val locale = currentLocale()
+    val window = agendaRangeWindowSummary(range, start, end, locale)
+    Column(modifier = modifier) {
+        Text(
+            text = stringResource(R.string.agenda_range_showing_label),
+            style = MaterialTheme.typography.labelMedium,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+        )
+        Text(
+            text = "${agendaRangeLabel(range)}, $window",
+            style = MaterialTheme.typography.titleMedium,
+            color = MaterialTheme.colorScheme.onSurface,
+        )
+    }
+}
+
+@Composable
+private fun AgendaContent(
+    state: AgendaUiState,
+    pastDisplay: PastEventDisplay,
+    onRetry: () -> Unit,
+    onEventClick: (EventInstance) -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    when (state) {
+        AgendaUiState.Loading -> Box(modifier)
+        is AgendaUiState.Failure -> Box(modifier) {
+            CalendarFailure(reason = state.reason, onRetry = onRetry)
+        }
+        is AgendaUiState.Success -> {
+            val now by rememberCurrentMinute()
+            // Hiding drops finished events — and any day they leave empty; dimming
+            // keeps them but fades the row. Recomputed each minute so events fall
+            // away (or fade) as they end while the screen stays open.
+            val days = if (pastDisplay == PastEventDisplay.HIDE) {
+                state.days.mapNotNull { day ->
+                    val remaining = day.events.filterNot { it.hasEnded(now) }
+                    if (remaining.isEmpty()) null else day.copy(events = remaining)
+                }
+            } else {
+                state.days
+            }
+            if (days.isEmpty()) {
+                AgendaEmpty(modifier)
+            } else {
+                AgendaList(
+                    days = days,
+                    today = state.today,
+                    dimPast = pastDisplay == PastEventDisplay.DIM,
+                    now = now,
+                    onEventClick = onEventClick,
+                    modifier = modifier,
+                )
+            }
+        }
+    }
+}
+
+@OptIn(ExperimentalFoundationApi::class)
+@Composable
+private fun AgendaList(
+    days: List<AgendaDay>,
+    today: LocalDate,
+    dimPast: Boolean,
+    now: Instant,
+    onEventClick: (EventInstance) -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    LazyColumn(
+        modifier = modifier,
+        // Bottom inset clears the FAB stack so the last row stays tappable.
+        contentPadding = PaddingValues(top = 8.dp, bottom = 96.dp),
+    ) {
+        days.forEach { day ->
+            stickyHeader(key = "header-${day.date}") {
+                AgendaDayHeader(date = day.date, today = today)
+            }
+            itemsIndexed(
+                items = day.events,
+                key = { _, event -> event.instanceId },
+            ) { index, event ->
+                AgendaEventRow(
+                    event = event,
+                    position = positionOf(index, day.events.size),
+                    dimmed = dimPast && event.hasEnded(now),
+                    modifier = calendarAnimateItem(),
+                    onClick = { onEventClick(event) },
+                )
+            }
+            item(key = "gap-${day.date}") { Spacer(Modifier.height(8.dp)) }
+        }
+    }
+}
+
+@Composable
+private fun AgendaDayHeader(date: LocalDate, today: LocalDate) {
+    Surface(
+        color = MaterialTheme.colorScheme.surface,
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Text(
+            text = agendaDayLabel(date, today),
+            style = MaterialTheme.typography.titleSmall,
+            color = if (date == today) {
+                MaterialTheme.colorScheme.primary
+            } else {
+                MaterialTheme.colorScheme.onSurfaceVariant
+            },
+            modifier = Modifier.padding(start = 28.dp, end = 28.dp, top = 16.dp, bottom = 8.dp),
+        )
+    }
+}
+
+@Composable
+private fun AgendaEventRow(
+    event: EventInstance,
+    position: Position,
+    dimmed: Boolean,
+    modifier: Modifier = Modifier,
+    onClick: () -> Unit,
+) {
+    val dark = isSystemInDarkTheme()
+    val title = event.title.ifBlank { stringResource(R.string.event_untitled) }
+    GroupedRow(
+        modifier = if (dimmed) modifier.alpha(EventDimAlpha) else modifier,
+        title = title,
+        summary = agendaTimeSummary(event),
+        position = position,
+        minHeight = 64.dp,
+        leading = {
+            Box(
+                modifier = Modifier
+                    .size(width = 6.dp, height = 36.dp)
+                    .clip(RoundedCornerShape(3.dp))
+                    .background(pastelize(event.color, dark)),
+            )
+        },
+        onClick = onClick,
+    )
+}
+
+@Composable
+private fun AgendaEmpty(modifier: Modifier = Modifier) {
+    Column(
+        modifier = modifier.padding(32.dp),
+        verticalArrangement = Arrangement.Center,
+        horizontalAlignment = Alignment.CenterHorizontally,
+    ) {
+        Icon(
+            imageVector = Icons.Filled.Coffee,
+            contentDescription = null,
+            tint = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.size(48.dp),
+        )
+        Spacer(Modifier.height(16.dp))
+        Text(
+            text = stringResource(R.string.agenda_empty_title),
+            style = MaterialTheme.typography.titleMedium,
+            textAlign = TextAlign.Center,
+        )
+    }
+}
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+private fun AgendaTopBar(
+    selectedView: CalendarView,
+    onCycleView: () -> Unit,
+    onOpenDrawer: () -> Unit,
+    onOpenSearch: () -> Unit,
+    scrollBehavior: TopAppBarScrollBehavior,
+) {
+    TopAppBar(
+        title = {
+            Text(
+                text = stringResource(R.string.view_agenda),
+                style = MaterialTheme.typography.titleLarge,
+            )
+        },
+        navigationIcon = {
+            IconButton(onClick = onOpenDrawer) {
+                Icon(
+                    imageVector = Icons.Default.Menu,
+                    contentDescription = stringResource(R.string.month_open_menu),
+                )
+            }
+        },
+        actions = {
+            IconButton(onClick = onOpenSearch) {
+                Icon(
+                    imageVector = Icons.Default.Search,
+                    contentDescription = stringResource(R.string.search_action),
+                )
+            }
+            ViewSwitcherPill(
+                current = selectedView,
+                onCycle = onCycleView,
+                modifier = Modifier.padding(end = 8.dp),
+            )
+        },
+        colors = TopAppBarDefaults.topAppBarColors(
+            containerColor = MaterialTheme.colorScheme.surface,
+            scrolledContainerColor = MaterialTheme.colorScheme.surfaceContainer,
+        ),
+        scrollBehavior = scrollBehavior,
+    )
+}
+
+/** "Today · Wed, 17. Jun 2026" — relative word for today/tomorrow, else the date. */
+@Composable
+private fun agendaDayLabel(date: LocalDate, today: LocalDate): String {
+    val relative = when (date) {
+        today -> stringResource(R.string.agenda_header_today)
+        today.plus(1, DateTimeUnit.DAY) -> stringResource(R.string.agenda_header_tomorrow)
+        else -> null
+    }
+    val formatted = formatAgendaDate(date)
+    return if (relative != null) "$relative · $formatted" else formatted
+}
+
+/** Time line under the title: "09:00 – 10:00 · Location", "All day", etc. */
+@Composable
+private fun agendaTimeSummary(event: EventInstance): String {
+    val time = if (event.isAllDay) {
+        stringResource(R.string.event_detail_all_day)
+    } else {
+        val is24Hour = LocalUse24HourFormat.current
+        val locale = currentLocale()
+        "${formatTime(event.start, is24Hour, locale)} – ${formatTime(event.end, is24Hour, locale)}"
+    }
+    val location = event.location?.takeIf { it.isNotBlank() }
+    return if (location != null) "$time · $location" else time
+}
+
+private fun formatTime(instant: Instant, is24Hour: Boolean, locale: Locale): String {
+    val t = instant.toLocalDateTime(zone).time
+    return formatTimeOfDay(t.hour, t.minute, is24Hour, locale)
+}
+
+private fun formatAgendaDate(date: LocalDate): String {
+    val locale = Locale.getDefault()
+    val java = java.time.LocalDate.of(date.year, date.month.ordinal + 1, date.day)
+    val weekday = java.dayOfWeek.getDisplayName(JavaTextStyle.SHORT, locale)
+    val monthName = java.month.getDisplayName(JavaTextStyle.SHORT, locale)
+    return "$weekday, ${date.day}. $monthName ${date.year}"
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/agenda/AgendaUiState.kt

@@ -0,0 +1,65 @@
+package de.jeanlucmakiola.calendula.ui.agenda
+
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.domain.FailureReason
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
+
+/** One calendar day with at least one event, for the agenda list. */
+data class AgendaDay(
+    val date: LocalDate,
+    /** Events on this day, all-day first then ascending by start time. */
+    val events: List<EventInstance>,
+)
+
+/**
+ * Group flat [instances] into forward-looking [AgendaDay]s (only days that
+ * actually carry events). An event that began before [anchor] (ongoing or
+ * multi-day) is clamped to the anchor day so it still surfaces on top. Within a
+ * day, all-day events sort first, then ascending by start time, then title.
+ *
+ * Shared by the Agenda screen and the agenda home-screen widget so both group
+ * and order identically.
+ */
+fun groupAgendaDays(
+    anchor: LocalDate,
+    instances: List<EventInstance>,
+    zone: TimeZone,
+): List<AgendaDay> =
+    instances
+        .groupBy { it.start.toLocalDateTime(zone).date.coerceAtLeast(anchor) }
+        .toSortedMap()
+        .map { (date, dayEvents) ->
+            AgendaDay(
+                date = date,
+                events = dayEvents.sortedWith(
+                    compareByDescending<EventInstance> { it.isAllDay }
+                        .thenBy { it.start }
+                        .thenBy { it.title },
+                ),
+            )
+        }
+
+/**
+ * State for the Agenda view: a flat, forward-looking list of upcoming events
+ * grouped by day (only days that actually have events appear).
+ */
+sealed interface AgendaUiState {
+    data object Loading : AgendaUiState
+    data class Failure(val reason: FailureReason) : AgendaUiState
+    data class Success(
+        /** First day of the loaded window (today, or a jumped-to date). */
+        val anchor: LocalDate,
+        val today: LocalDate,
+        val days: List<AgendaDay>,
+        /** The range currently in effect — the saved default or a session override. */
+        val range: AgendaRange,
+        /** True when [range] is a temporary in-view override of the saved default. */
+        val rangeIsOverride: Boolean,
+        /** Last day the current [range] covers (inclusive), for the range header. */
+        val rangeEnd: LocalDate,
+        /** Whether to show the top range bar — header + switcher (toggle, on by default). */
+        val showRangeBar: Boolean,
+    ) : AgendaUiState
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/agenda/AgendaViewModel.kt

@@ -0,0 +1,171 @@
+package de.jeanlucmakiola.calendula.ui.agenda
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import dagger.hilt.android.lifecycle.HiltViewModel
+import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
+import de.jeanlucmakiola.calendula.data.di.IoDispatcher
+import de.jeanlucmakiola.calendula.data.prefs.PastEventDisplay
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import de.jeanlucmakiola.calendula.data.prefs.resolveFirstDay
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.domain.FailureReason
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.catch
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.datetime.DateTimeUnit
+import kotlinx.datetime.DayOfWeek
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import java.util.Locale
+import kotlinx.datetime.atStartOfDayIn
+import kotlinx.datetime.atTime
+import kotlinx.datetime.plus
+import kotlinx.datetime.toInstant
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Clock
+import kotlin.time.Instant
+import javax.inject.Inject
+
+@OptIn(ExperimentalCoroutinesApi::class)
+@HiltViewModel
+class AgendaViewModel @Inject constructor(
+    private val repository: CalendarRepository,
+    settingsPrefs: SettingsPrefs,
+    @IoDispatcher private val io: CoroutineDispatcher,
+) : ViewModel() {
+
+    // The saved agenda range plus the range-bar visibility toggle.
+    private val agendaSettings = combine(
+        settingsPrefs.agendaScreenRange,
+        settingsPrefs.agendaShowRangeBar,
+    ) { range, showBar -> AgendaSettings(range, showBar) }
+
+    // First day of the week, for the calendar-aligned "this week" range.
+    private val weekStartDay = settingsPrefs.weekStart
+        .map { it.resolveFirstDay(Locale.getDefault()) }
+
+    /**
+     * How to treat events that already ended today (show / dim / hide). A display
+     * concern only, so it rides alongside the data state rather than re-querying;
+     * the screen combines it with a per-minute "now" to fade or drop past rows.
+     */
+    val pastEventDisplay: StateFlow<PastEventDisplay> = settingsPrefs.pastEventDisplay
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5_000L),
+            initialValue = PastEventDisplay.SHOW,
+        )
+
+    private val zone = TimeZone.currentSystemDefault()
+
+    private val todayDate: LocalDate
+        get() = Clock.System.now().toLocalDateTime(zone).date
+
+    private val _anchor = MutableStateFlow(todayDate)
+    val anchor: StateFlow<LocalDate> = _anchor
+
+    // A transient, in-view override of the saved agenda range. Held in memory
+    // (not persisted), so it survives view switches and rotation within the
+    // session but resets to the saved default when the app is relaunched.
+    private val _rangeOverride = MutableStateFlow<AgendaRange?>(null)
+
+    val state: StateFlow<AgendaUiState> =
+        combine(_anchor, agendaSettings, _rangeOverride, weekStartDay) { anchor, settings, override, weekStart ->
+            AgendaParams(
+                anchor = anchor,
+                range = override ?: settings.range,
+                rangeIsOverride = override != null && override != settings.range,
+                weekStart = weekStart,
+                showRangeBar = settings.showBar,
+            )
+        }
+        .flatMapLatest { params ->
+            val window = agendaRange(
+                params.anchor,
+                params.range.dayCount(params.anchor, params.weekStart) - 1,
+                zone,
+            )
+            combine(
+                repository.calendars(),
+                repository.instances(window),
+            ) { calendars, instances ->
+                buildState(params, calendars, instances)
+            }
+        }
+        .catch { emit(AgendaUiState.Failure(FailureReason.ProviderUnavailable)) }
+        .flowOn(io)
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5_000L),
+            initialValue = AgendaUiState.Loading,
+        )
+
+    fun goToToday() {
+        _anchor.value = todayDate
+    }
+
+    /** Jump the agenda window to start on a specific date (drawer jump-to-date). */
+    fun goToDate(date: LocalDate) {
+        _anchor.value = date
+    }
+
+    /** Temporarily override the agenda range for this session (the bottom-left pill). */
+    fun setRangeOverride(range: AgendaRange) {
+        _rangeOverride.value = range
+    }
+
+    private data class AgendaSettings(
+        val range: AgendaRange,
+        val showBar: Boolean,
+    )
+
+    private data class AgendaParams(
+        val anchor: LocalDate,
+        val range: AgendaRange,
+        val rangeIsOverride: Boolean,
+        val weekStart: DayOfWeek,
+        val showRangeBar: Boolean,
+    )
+
+    private fun buildState(
+        params: AgendaParams,
+        calendars: List<CalendarSource>,
+        instances: List<EventInstance>,
+    ): AgendaUiState {
+        if (calendars.isEmpty()) {
+            return AgendaUiState.Failure(FailureReason.NoCalendarsConfigured)
+        }
+        val anchor = params.anchor
+        val days = groupAgendaDays(anchor, instances, zone)
+        val rangeEnd = anchor.plus(
+            params.range.dayCount(anchor, params.weekStart) - 1,
+            DateTimeUnit.DAY,
+        )
+        return AgendaUiState.Success(
+            anchor = anchor,
+            today = todayDate,
+            days = days,
+            range = params.range,
+            rangeIsOverride = params.rangeIsOverride,
+            rangeEnd = rangeEnd,
+            showRangeBar = params.showRangeBar,
+        )
+    }
+}
+
+/** Inclusive instant range from the start of [anchor] through [days] days ahead. */
+internal fun agendaRange(anchor: LocalDate, days: Int, zone: TimeZone): ClosedRange<Instant> {
+    val from = anchor.atStartOfDayIn(zone)
+    val to = anchor.plus(days, DateTimeUnit.DAY).atTime(23, 59, 59).toInstant(zone)
+    return from..to
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/calendars/CalendarsScreen.kt

@@ -0,0 +1,943 @@
+package de.jeanlucmakiola.calendula.ui.calendars
+
+import android.accounts.AccountManager
+import android.content.Context
+import android.content.Intent
+import android.provider.Settings
+import android.text.format.DateUtils
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.background
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.ColumnScope
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material.icons.automirrored.filled.Notes
+import androidx.compose.material.icons.automirrored.filled.OpenInNew
+import androidx.compose.material.icons.filled.Add
+import androidx.compose.material.icons.filled.CalendarMonth
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material.icons.filled.Cloud
+import androidx.compose.material.icons.filled.Delete
+import androidx.compose.material.icons.filled.FileDownload
+import androidx.compose.material.icons.filled.MoreVert
+import androidx.compose.material.icons.filled.Palette
+import androidx.compose.material.icons.filled.PhoneAndroid
+import androidx.compose.material.icons.filled.Schedule
+import androidx.compose.material.icons.filled.Visibility
+import androidx.compose.material.icons.filled.VisibilityOff
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.Button
+import androidx.compose.material3.DropdownMenu
+import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.HorizontalDivider
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.SnackbarHost
+import androidx.compose.material3.SnackbarHostState
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Switch
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.material3.TopAppBar
+import androidx.compose.material3.TopAppBarDefaults
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.alpha
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.ImageBitmap
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.pluralStringResource
+import androidx.compose.ui.res.stringArrayResource
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.semantics.contentDescription
+import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.text.input.KeyboardCapitalization
+import androidx.compose.ui.unit.dp
+import androidx.core.graphics.drawable.toBitmap
+import androidx.core.net.toUri
+import androidx.documentfile.provider.DocumentFile
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.data.prefs.BackupStatus
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.data.calendar.CalendarColorPalette
+import de.jeanlucmakiola.calendula.ui.common.CalendarColorChip
+import de.jeanlucmakiola.calendula.ui.common.DialogAmountField
+import de.jeanlucmakiola.calendula.ui.common.DialogUnitDropdown
+import de.jeanlucmakiola.calendula.ui.common.calendarCollapseExit
+import de.jeanlucmakiola.calendula.ui.common.calendarExpandEnter
+import de.jeanlucmakiola.calendula.ui.common.predictiveBack
+import de.jeanlucmakiola.calendula.ui.common.CollapsingScaffold
+import de.jeanlucmakiola.calendula.ui.common.ColorSwatchRow
+import de.jeanlucmakiola.calendula.ui.common.GroupedRow
+import de.jeanlucmakiola.calendula.ui.common.InlineTextField
+import de.jeanlucmakiola.calendula.ui.common.Position
+import de.jeanlucmakiola.calendula.ui.common.pastelize
+import java.time.LocalDate
+
+/** Sentinel [editorId] meaning "the editor is composing a new calendar". */
+private const val NEW_CALENDAR_ID = Long.MIN_VALUE
+
+/**
+ * Calendar manager (reached from Settings). Lists the app's own device-only
+ * calendars with create / rename / recolor / delete (via a full-screen editor),
+ * and lists synced calendars read-only with a per-account "manage in the source
+ * app" deep-link — the app never touches a synced calendar's server. A
+ * full-screen destination; [onBack] pops it.
+ */
+@Composable
+fun CalendarsScreen(
+    onBack: () -> Unit,
+    viewModel: CalendarsViewModel = hiltViewModel(),
+) {
+    val calendars by viewModel.calendars.collectAsStateWithLifecycle()
+    val disabledIds by viewModel.disabledCalendarIds.collectAsStateWithLifecycle()
+    val error by viewModel.error.collectAsStateWithLifecycle()
+    val backupResult by viewModel.backupResult.collectAsStateWithLifecycle()
+    val autoBackup by viewModel.autoBackup.collectAsStateWithLifecycle()
+
+    // null = list; NEW_CALENDAR_ID = create; any other id = edit that calendar.
+    // [editorSession] bumps on every open so the editor's field state resets for
+    // a fresh open while still surviving configuration changes within one open.
+    var editorId by rememberSaveable { mutableStateOf<Long?>(null) }
+    var editorSession by rememberSaveable { mutableStateOf(0) }
+
+    if (editorId != null) {
+        val editing = calendars.firstOrNull { it.id == editorId }
+        CalendarEditor(
+            sessionKey = editorSession,
+            isNew = editorId == NEW_CALENDAR_ID,
+            initialName = editing?.displayName.orEmpty(),
+            initialColor = editing?.color ?: CalendarColorPalette.all.first(),
+            initialDescription = editing?.description.orEmpty(),
+            onSave = { name, color, description ->
+                val id = editorId
+                if (id == null || id == NEW_CALENDAR_ID) {
+                    viewModel.createCalendar(name, color, description)
+                } else {
+                    viewModel.updateCalendar(id, name, color, description)
+                }
+                editorId = null
+            },
+            onDelete = {
+                editorId?.takeIf { it != NEW_CALENDAR_ID }?.let(viewModel::deleteCalendar)
+                editorId = null
+            },
+            onClose = { editorId = null },
+        )
+    } else {
+        CalendarsList(
+            local = calendars.filter { it.isLocal },
+            synced = calendars.filterNot { it.isLocal },
+            disabledIds = disabledIds,
+            error = error,
+            onConsumeError = viewModel::consumeError,
+            backupResult = backupResult,
+            onExportBackup = viewModel::exportBackup,
+            onConsumeBackupResult = viewModel::consumeBackupResult,
+            autoBackup = autoBackup,
+            onSetAutoBackupEnabled = viewModel::setAutoBackupEnabled,
+            onSetAutoBackupInterval = viewModel::setAutoBackupIntervalMinutes,
+            onSetAutoBackupFolder = viewModel::setAutoBackupFolder,
+            onBack = onBack,
+            onAdd = { editorSession++; editorId = NEW_CALENDAR_ID },
+            onEdit = { calendar -> editorSession++; editorId = calendar.id },
+            onSetDisabled = viewModel::setDisabled,
+            onSetAccountDisabled = viewModel::setAccountDisabled,
+        )
+    }
+}
+
+@Composable
+private fun CalendarsList(
+    local: List<CalendarSource>,
+    synced: List<CalendarSource>,
+    disabledIds: Set<Long>,
+    error: Boolean,
+    onConsumeError: () -> Unit,
+    backupResult: BackupResult?,
+    onExportBackup: (android.net.Uri) -> Unit,
+    onConsumeBackupResult: () -> Unit,
+    autoBackup: AutoBackupUiState,
+    onSetAutoBackupEnabled: (Boolean) -> Unit,
+    onSetAutoBackupInterval: (Long) -> Unit,
+    onSetAutoBackupFolder: (android.net.Uri) -> Unit,
+    onBack: () -> Unit,
+    onAdd: () -> Unit,
+    onEdit: (CalendarSource) -> Unit,
+    onSetDisabled: (Long, Boolean) -> Unit,
+    onSetAccountDisabled: (Collection<Long>, Boolean) -> Unit,
+) {
+    val context = LocalContext.current
+    val snackbarHostState = remember { SnackbarHostState() }
+    // Accounts the user has folded shut; empty = all expanded (keeps every
+    // calendar visible by default, the section is collapsible for tidiness).
+    var collapsedAccounts by remember { mutableStateOf(emptySet<String>()) }
+    var localExpanded by remember { mutableStateOf(true) }
+    val writeErrorText = stringResource(R.string.calendars_write_error)
+
+    LaunchedEffect(error) {
+        if (error) {
+            snackbarHostState.showSnackbar(writeErrorText)
+            onConsumeError()
+        }
+    }
+
+    // SAF "create document" target for the backup file. The picked Uri is handed
+    // to the VM to stream the .ics into.
+    val createBackup = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.CreateDocument("text/calendar"),
+    ) { uri -> uri?.let(onExportBackup) }
+
+    // SAF folder picker for the automatic-backup destination; the VM persists the
+    // write grant so background runs can keep writing to it.
+    val pickFolder = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.OpenDocumentTree(),
+    ) { uri -> uri?.let(onSetAutoBackupFolder) }
+    var showInterval by remember { mutableStateOf(false) }
+
+    val backupFailedText = stringResource(R.string.calendars_backup_failed)
+    LaunchedEffect(backupResult) {
+        when (val r = backupResult) {
+            is BackupResult.Success -> {
+                snackbarHostState.showSnackbar(
+                    context.resources.getQuantityString(
+                        R.plurals.calendars_backup_done, r.eventCount, r.eventCount,
+                    ),
+                )
+                onConsumeBackupResult()
+            }
+            BackupResult.Failure -> {
+                snackbarHostState.showSnackbar(backupFailedText)
+                onConsumeBackupResult()
+            }
+            null -> Unit
+        }
+    }
+
+    CollapsingScaffold(
+        title = stringResource(R.string.calendars_title),
+        onBack = onBack,
+        snackbarHost = { SnackbarHost(snackbarHostState) },
+    ) {
+        // What the per-calendar / per-account switches below actually do.
+        HintText(stringResource(R.string.calendars_disable_hint))
+
+        // Local (device-only) calendars — one collapsible group. The header's
+        // "+" adds a calendar; the switch enables/disables them all at once;
+        // tapping a calendar row opens its editor.
+        val localDisabled = local.isNotEmpty() && local.all { it.id in disabledIds }
+        CalendarGroup(
+            title = stringResource(R.string.calendars_local_header),
+            expanded = localExpanded,
+            bodyHasRows = local.isNotEmpty(),
+            headerDisabled = localDisabled,
+            leading = { Box(dimIf(localDisabled)) { LeadingAvatar(Icons.Default.PhoneAndroid) } },
+            manageIcon = Icons.Default.Add,
+            manageLabel = stringResource(R.string.calendars_add),
+            onManage = onAdd,
+            onToggleExpand = { localExpanded = !localExpanded },
+            showToggleAll = local.isNotEmpty(),
+            allEnabled = local.none { it.id in disabledIds },
+            onToggleAll = { enabled -> onSetAccountDisabled(local.map { it.id }, !enabled) },
+        ) {
+            if (local.isEmpty()) {
+                HintText(stringResource(R.string.calendars_local_empty))
+            } else {
+                local.forEachIndexed { index, calendar ->
+                    val disabled = calendar.id in disabledIds
+                    GroupedRow(
+                        title = calendar.displayName,
+                        summary = calendar.description,
+                        position = if (index == local.lastIndex) Position.Bottom else Position.Middle,
+                        container = MaterialTheme.colorScheme.surfaceContainerHighest,
+                        dimmed = disabled,
+                        leading = { CalendarColorChip(calendar.color, dimIf(disabled)) },
+                        trailing = {
+                            EnableSwitch(
+                                calendarName = calendar.displayName,
+                                enabled = !disabled,
+                                onToggle = { enabled -> onSetDisabled(calendar.id, !enabled) },
+                            )
+                        },
+                        onClick = { onEdit(calendar) },
+                    )
+                }
+            }
+        }
+
+        // Backup — local calendars have no sync, so a .ics export is their only
+        // safety net. Offered only when there is something to back up.
+        if (local.isNotEmpty()) {
+            Spacer(Modifier.height(16.dp))
+            SectionHeader(stringResource(R.string.calendars_backup_header))
+            HintText(stringResource(R.string.calendars_backup_hint))
+            // One connected card: the one-time export on top, then automatic
+            // backup (and its folder/interval rows when on).
+            GroupedRow(
+                title = stringResource(R.string.calendars_backup_action),
+                position = Position.Top,
+                leading = { LeadingAvatar(Icons.Default.FileDownload) },
+                onClick = {
+                    runCatching { createBackup.launch("calendula-backup-${LocalDate.now()}.ics") }
+                },
+            )
+            GroupedRow(
+                title = stringResource(R.string.calendars_auto_backup),
+                summary = stringResource(R.string.calendars_auto_backup_hint),
+                position = if (autoBackup.enabled) Position.Middle else Position.Bottom,
+                leading = { LeadingAvatar(Icons.Default.Schedule) },
+                trailing = {
+                    Switch(checked = autoBackup.enabled, onCheckedChange = onSetAutoBackupEnabled)
+                },
+                onClick = { onSetAutoBackupEnabled(!autoBackup.enabled) },
+            )
+            if (autoBackup.enabled) {
+                GroupedRow(
+                    title = stringResource(R.string.calendars_auto_backup_folder),
+                    summary = rememberFolderName(autoBackup.folderUri)
+                        ?: stringResource(R.string.calendars_auto_backup_folder_unset),
+                    position = Position.Middle,
+                    onClick = { runCatching { pickFolder.launch(null) } },
+                )
+                GroupedRow(
+                    title = stringResource(R.string.calendars_auto_backup_interval),
+                    summary = backupIntervalLabel(autoBackup.intervalMinutes),
+                    position = Position.Bottom,
+                    onClick = { showInterval = true },
+                )
+                HintText(backupStatusText(autoBackup.status))
+            }
+        }
+
+        Spacer(Modifier.height(16.dp))
+
+        // Synced calendars — read-only, grouped by account. Each account is a
+        // collapsible group whose header opens the source app (icon) and toggles
+        // all of its calendars at once (switch).
+        SectionHeader(stringResource(R.string.calendars_synced_header))
+        HintText(stringResource(R.string.calendars_synced_hint))
+        synced
+            .groupBy { it.accountName.ifBlank { it.accountType } }
+            .forEach { (account, cals) ->
+                val expanded = account !in collapsedAccounts
+                val accountType = cals.first().accountType
+                val accountDisabled = cals.all { it.id in disabledIds }
+                Spacer(Modifier.height(16.dp))
+                CalendarGroup(
+                    title = account,
+                    expanded = expanded,
+                    bodyHasRows = true,
+                    headerDisabled = accountDisabled,
+                    leading = { Box(dimIf(accountDisabled)) { SourceLogo(accountType) } },
+                    manageIcon = Icons.AutoMirrored.Filled.OpenInNew,
+                    manageLabel = stringResource(R.string.calendars_manage_in_app),
+                    onManage = {
+                        runCatching { context.startActivity(sourceAppIntent(context, accountType)) }
+                    },
+                    onToggleExpand = {
+                        collapsedAccounts = if (expanded) {
+                            collapsedAccounts + account
+                        } else {
+                            collapsedAccounts - account
+                        }
+                    },
+                    showToggleAll = true,
+                    allEnabled = cals.none { it.id in disabledIds },
+                    onToggleAll = { enabled -> onSetAccountDisabled(cals.map { it.id }, !enabled) },
+                ) {
+                    cals.forEachIndexed { index, calendar ->
+                        val disabled = calendar.id in disabledIds
+                        GroupedRow(
+                            title = calendar.displayName,
+                            position = if (index == cals.lastIndex) Position.Bottom else Position.Middle,
+                            container = MaterialTheme.colorScheme.surfaceContainerHighest,
+                            dimmed = disabled,
+                            leading = { CalendarColorChip(calendar.color, dimIf(disabled)) },
+                            trailing = {
+                                EnableSwitch(
+                                    calendarName = calendar.displayName,
+                                    enabled = !disabled,
+                                    onToggle = { enabled -> onSetDisabled(calendar.id, !enabled) },
+                                )
+                            },
+                        )
+                    }
+                }
+            }
+    }
+
+    if (showInterval) {
+        BackupIntervalDialog(
+            currentMinutes = autoBackup.intervalMinutes,
+            onConfirm = onSetAutoBackupInterval,
+            onDismiss = { showInterval = false },
+        )
+    }
+}
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+private fun CalendarEditor(
+    sessionKey: Int,
+    isNew: Boolean,
+    initialName: String,
+    initialColor: Int,
+    initialDescription: String,
+    onSave: (name: String, color: Int, description: String?) -> Unit,
+    onDelete: () -> Unit,
+    onClose: () -> Unit,
+) {
+    var name by rememberSaveable(sessionKey) { mutableStateOf(initialName) }
+    var color by rememberSaveable(sessionKey) { mutableStateOf(initialColor) }
+    var description by rememberSaveable(sessionKey) { mutableStateOf(initialDescription) }
+    var confirmDelete by remember { mutableStateOf(false) }
+    val dark = isSystemInDarkTheme()
+
+    Scaffold(
+        modifier = Modifier
+            .predictiveBack(onBack = onClose)
+            .fillMaxSize()
+            .background(MaterialTheme.colorScheme.surface),
+        topBar = {
+            TopAppBar(
+                title = {
+                    Text(
+                        stringResource(
+                            if (isNew) R.string.calendars_new_title
+                            else R.string.calendars_edit_title,
+                        ),
+                    )
+                },
+                navigationIcon = {
+                    IconButton(onClick = onClose) {
+                        Icon(
+                            Icons.Default.Close,
+                            contentDescription = stringResource(R.string.event_edit_close),
+                        )
+                    }
+                },
+                actions = {
+                    if (!isNew) {
+                        IconButton(onClick = { confirmDelete = true }) {
+                            Icon(
+                                Icons.Default.Delete,
+                                contentDescription = stringResource(R.string.event_detail_delete),
+                                tint = MaterialTheme.colorScheme.error,
+                            )
+                        }
+                    }
+                    // Filled save button, matching the event editor's top bar.
+                    Button(
+                        onClick = {
+                            onSave(name.trim(), color, description.trim().ifEmpty { null })
+                        },
+                        enabled = name.isNotBlank(),
+                        modifier = Modifier.padding(end = 12.dp),
+                    ) {
+                        Text(stringResource(R.string.event_edit_save))
+                    }
+                },
+                colors = TopAppBarDefaults.topAppBarColors(
+                    containerColor = MaterialTheme.colorScheme.surface,
+                ),
+            )
+        },
+    ) { innerPadding ->
+        Column(
+            modifier = Modifier
+                .padding(innerPadding)
+                .fillMaxSize()
+                .verticalScroll(rememberScrollState())
+                .padding(horizontal = 16.dp, vertical = 8.dp),
+            verticalArrangement = Arrangement.spacedBy(12.dp),
+        ) {
+            EditorCard(icon = Icons.Default.CalendarMonth, iconTint = pastelize(color, dark)) {
+                InlineTextField(
+                    value = name,
+                    onValueChange = { name = it },
+                    placeholder = stringResource(R.string.calendars_name_label),
+                    textStyle = MaterialTheme.typography.titleLarge,
+                    capitalization = KeyboardCapitalization.Sentences,
+                )
+            }
+            EditorCard(
+                icon = Icons.Default.Palette,
+                iconTint = MaterialTheme.colorScheme.onSurfaceVariant,
+                iconAtTop = true,
+            ) {
+                Text(
+                    text = stringResource(R.string.calendars_color_label),
+                    style = MaterialTheme.typography.labelLarge,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+                Spacer(Modifier.height(12.dp))
+                ColorSwatchRow(
+                    colors = CalendarColorPalette.all,
+                    selected = color,
+                    onSelect = { color = it },
+                    dark = dark,
+                )
+            }
+            EditorCard(
+                icon = Icons.AutoMirrored.Filled.Notes,
+                iconTint = MaterialTheme.colorScheme.onSurfaceVariant,
+                iconAtTop = true,
+            ) {
+                InlineTextField(
+                    value = description,
+                    onValueChange = { description = it },
+                    placeholder = stringResource(R.string.calendars_description_hint),
+                    singleLine = false,
+                    minLines = 2,
+                    capitalization = KeyboardCapitalization.Sentences,
+                )
+            }
+        }
+    }
+
+    if (confirmDelete) {
+        AlertDialog(
+            onDismissRequest = { confirmDelete = false },
+            title = { Text(stringResource(R.string.calendars_delete_confirm_title)) },
+            text = {
+                Text(stringResource(R.string.calendars_delete_confirm_message, initialName))
+            },
+            confirmButton = {
+                TextButton(onClick = {
+                    confirmDelete = false
+                    onDelete()
+                }) {
+                    Text(
+                        stringResource(R.string.event_detail_delete),
+                        color = MaterialTheme.colorScheme.error,
+                    )
+                }
+            },
+            dismissButton = {
+                TextButton(onClick = { confirmDelete = false }) {
+                    Text(stringResource(R.string.dialog_cancel))
+                }
+            },
+        )
+    }
+}
+
+/**
+ * The per-row enable/disable control. Checked = the calendar is shown in the
+ * app; unchecking disables it (events, filters and pickers all drop it) without
+ * touching any provider data. Carries its own content description so the toggle
+ * is self-describing to screen readers even on a dimmed row.
+ */
+@Composable
+private fun EnableSwitch(
+    calendarName: String,
+    enabled: Boolean,
+    onToggle: (Boolean) -> Unit,
+) {
+    val label = stringResource(R.string.calendars_show_in_app_a11y, calendarName)
+    Switch(
+        checked = enabled,
+        onCheckedChange = onToggle,
+        modifier = Modifier.semantics { contentDescription = label },
+    )
+}
+
+/** Fade a leading element to the M3 disabled emphasis when [disabled]. */
+private fun dimIf(disabled: Boolean): Modifier =
+    if (disabled) Modifier.alpha(0.38f) else Modifier
+
+/** Tonal field card matching the event editor's design (icon + content). */
+@Composable
+private fun EditorCard(
+    icon: ImageVector,
+    iconTint: Color,
+    iconAtTop: Boolean = false,
+    content: @Composable () -> Unit,
+) {
+    Surface(
+        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+        shape = RoundedCornerShape(16.dp),
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Row(
+            modifier = Modifier.padding(16.dp),
+            verticalAlignment = if (iconAtTop) Alignment.Top else Alignment.CenterVertically,
+        ) {
+            Icon(
+                imageVector = icon,
+                contentDescription = null,
+                tint = iconTint,
+                modifier = Modifier
+                    .padding(top = if (iconAtTop) 2.dp else 0.dp)
+                    .size(24.dp),
+            )
+            Spacer(Modifier.width(16.dp))
+            Column(modifier = Modifier.weight(1f)) { content() }
+        }
+    }
+}
+
+/**
+ * One collapsible calendar group rendered as a connected card. The header row is
+ * the card's top (tap to expand/collapse): a [leading] source mark (the account
+ * app's logo, or a device chip for local), the group [title] and a trailing
+ * overflow (⋮) menu holding the account-level actions — enable/disable every
+ * calendar at once (when [showToggleAll]) and the manage/add action
+ * ([manageIcon] / [manageLabel] → [onManage]). The group's calendars render as
+ * the rows below via [body].
+ *
+ * The header keeps the standard row colour; the calendars it reveals sit one tone
+ * darker, so the group reads as a header over nested content. Once [headerDisabled]
+ * (every calendar switched off) the header fades to the disabled emphasis so the
+ * whole group reads as off — not just via the menu. [bodyHasRows] is false when no
+ * calendar rows follow (e.g. an empty local group), so the header stays a
+ * standalone card rather than a top edge with nothing beneath it.
+ */
+@Composable
+private fun CalendarGroup(
+    title: String,
+    expanded: Boolean,
+    bodyHasRows: Boolean,
+    headerDisabled: Boolean,
+    leading: @Composable () -> Unit,
+    manageIcon: ImageVector,
+    manageLabel: String,
+    onManage: () -> Unit,
+    onToggleExpand: () -> Unit,
+    showToggleAll: Boolean,
+    allEnabled: Boolean,
+    onToggleAll: (Boolean) -> Unit,
+    body: @Composable ColumnScope.() -> Unit,
+) {
+    GroupedRow(
+        title = title,
+        position = if (expanded && bodyHasRows) Position.Top else Position.Alone,
+        dimmed = headerDisabled,
+        leading = leading,
+        trailing = {
+            CalendarGroupMenu(
+                title = title,
+                showToggleAll = showToggleAll,
+                allEnabled = allEnabled,
+                onToggleAll = onToggleAll,
+                manageIcon = manageIcon,
+                manageLabel = manageLabel,
+                onManage = onManage,
+            )
+        },
+        onClick = onToggleExpand,
+    )
+    AnimatedVisibility(
+        visible = expanded,
+        enter = calendarExpandEnter(),
+        exit = calendarCollapseExit(),
+    ) {
+        Column(content = body)
+    }
+}
+
+/**
+ * The account header's overflow (⋮) menu: the two account-level actions that
+ * don't fit on one line — "Enable/Disable all" (when [showToggleAll]) and the
+ * manage/add action. A rounded, tonal dropdown matching the app's surfaces, with
+ * the two actions divided for clear separation.
+ */
+@Composable
+private fun CalendarGroupMenu(
+    title: String,
+    showToggleAll: Boolean,
+    allEnabled: Boolean,
+    onToggleAll: (Boolean) -> Unit,
+    manageIcon: ImageVector,
+    manageLabel: String,
+    onManage: () -> Unit,
+) {
+    var open by remember { mutableStateOf(false) }
+    Box {
+        IconButton(onClick = { open = true }) {
+            Icon(
+                Icons.Default.MoreVert,
+                contentDescription = stringResource(R.string.calendars_account_menu_a11y, title),
+            )
+        }
+        DropdownMenu(
+            expanded = open,
+            onDismissRequest = { open = false },
+            shape = RoundedCornerShape(20.dp),
+            // A distinct tone + a lifted shadow so the menu reads as floating
+            // above the cards (which sit at surfaceContainerHigh) rather than
+            // blending into them.
+            containerColor = MaterialTheme.colorScheme.surfaceContainerLowest,
+            tonalElevation = 0.dp,
+            shadowElevation = 6.dp,
+        ) {
+            if (showToggleAll) {
+                DropdownMenuItem(
+                    text = {
+                        Text(
+                            stringResource(
+                                if (allEnabled) R.string.calendars_disable_all
+                                else R.string.calendars_enable_all,
+                            ),
+                        )
+                    },
+                    leadingIcon = {
+                        Icon(
+                            if (allEnabled) Icons.Default.VisibilityOff else Icons.Default.Visibility,
+                            contentDescription = null,
+                        )
+                    },
+                    onClick = {
+                        open = false
+                        onToggleAll(!allEnabled)
+                    },
+                )
+                HorizontalDivider(Modifier.padding(horizontal = 12.dp, vertical = 4.dp))
+            }
+            DropdownMenuItem(
+                text = { Text(manageLabel) },
+                leadingIcon = { Icon(manageIcon, contentDescription = null) },
+                onClick = {
+                    open = false
+                    onManage()
+                },
+            )
+        }
+    }
+}
+
+/**
+ * The source app's launcher icon (Google Calendar, DAVx5, Nextcloud, …) as a
+ * round 40dp chip, so each synced account is recognisable at a glance. We load
+ * whatever app owns the account from [PackageManager] rather than bundling brand
+ * logos — always accurate, nothing to license. Falls back to a neutral cloud
+ * chip when no installed app resolves for the account.
+ */
+@Composable
+private fun SourceLogo(accountType: String) {
+    val context = LocalContext.current
+    val logo = remember(accountType) { sourceAppLogo(context, accountType) }
+    if (logo != null) {
+        Image(
+            bitmap = logo,
+            contentDescription = null,
+            contentScale = ContentScale.Crop,
+            modifier = Modifier
+                .size(40.dp)
+                .clip(CircleShape),
+        )
+    } else {
+        LeadingAvatar(Icons.Default.Cloud)
+    }
+}
+
+/** The launcher icon of the app backing [accountType], preferring the human-facing app. */
+private fun sourceAppLogo(context: Context, accountType: String): ImageBitmap? {
+    val pm = context.packageManager
+    val candidates = buildList {
+        curatedSourcePackage(accountType)?.let { add(it) }
+        AccountManager.get(context).authenticatorTypes
+            .firstOrNull { it.type.equals(accountType, ignoreCase = true) }
+            ?.packageName
+            ?.let { add(it) }
+    }
+    for (pkg in candidates) {
+        val bitmap = runCatching { pm.getApplicationIcon(pkg).toBitmap() }.getOrNull()
+        if (bitmap != null) return bitmap.asImageBitmap()
+    }
+    return null
+}
+
+/** Neutral circular chip carrying an arbitrary icon (e.g. the local-device mark). */
+@Composable
+private fun LeadingAvatar(icon: ImageVector) {
+    Box(
+        modifier = Modifier
+            .size(40.dp)
+            .clip(CircleShape)
+            .background(MaterialTheme.colorScheme.surfaceContainerHighest),
+        contentAlignment = Alignment.Center,
+    ) {
+        Icon(
+            icon,
+            contentDescription = null,
+            tint = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.size(22.dp),
+        )
+    }
+}
+
+@Composable
+private fun SectionHeader(text: String) {
+    Text(
+        text = text,
+        style = MaterialTheme.typography.labelLarge,
+        color = MaterialTheme.colorScheme.primary,
+        modifier = Modifier.padding(start = 24.dp, end = 24.dp, top = 16.dp, bottom = 4.dp),
+    )
+}
+
+@Composable
+private fun HintText(text: String) {
+    Text(
+        text = text,
+        style = MaterialTheme.typography.bodySmall,
+        color = MaterialTheme.colorScheme.onSurfaceVariant,
+        modifier = Modifier.padding(horizontal = 24.dp, vertical = 4.dp),
+    )
+}
+
+/** Readable name of the persisted backup folder, resolved from its tree Uri. */
+@Composable
+private fun rememberFolderName(uriString: String?): String? {
+    val context = LocalContext.current
+    return remember(uriString) {
+        uriString?.let {
+            runCatching { DocumentFile.fromTreeUri(context, it.toUri())?.name }.getOrNull()
+        }
+    }
+}
+
+/** "Every 30 minutes" / "Every 2 hours" / "Every day" — the interval in its largest whole unit. */
+@Composable
+private fun backupIntervalLabel(minutes: Long): String {
+    val duration = when {
+        minutes % MINUTES_PER_WEEK == 0L ->
+            pluralStringResource(R.plurals.duration_weeks, (minutes / MINUTES_PER_WEEK).toInt(), (minutes / MINUTES_PER_WEEK).toInt())
+        minutes % MINUTES_PER_DAY == 0L ->
+            pluralStringResource(R.plurals.duration_days, (minutes / MINUTES_PER_DAY).toInt(), (minutes / MINUTES_PER_DAY).toInt())
+        minutes % 60L == 0L ->
+            pluralStringResource(R.plurals.duration_hours, (minutes / 60L).toInt(), (minutes / 60L).toInt())
+        else ->
+            pluralStringResource(R.plurals.duration_minutes, minutes.toInt(), minutes.toInt())
+    }
+    return stringResource(R.string.calendars_auto_backup_every, duration)
+}
+
+/** "Last backup: 5 minutes ago" / "… failed" / "No automatic backup yet". */
+@Composable
+private fun backupStatusText(status: BackupStatus): String {
+    if (status.lastRun == 0L) return stringResource(R.string.calendars_auto_backup_status_never)
+    val relative = DateUtils.getRelativeTimeSpanString(
+        status.lastRun, System.currentTimeMillis(), DateUtils.MINUTE_IN_MILLIS,
+    ).toString()
+    return if (status.lastSuccess) {
+        stringResource(R.string.calendars_auto_backup_status_ok, relative)
+    } else {
+        stringResource(R.string.calendars_auto_backup_status_failed, relative)
+    }
+}
+
+/** Amount + unit picker for the backup interval (floored at 30 minutes). */
+@Composable
+private fun BackupIntervalDialog(
+    currentMinutes: Long,
+    onConfirm: (Long) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    // minutes-per-unit for each entry; pick the largest unit the current value divides into.
+    val unitMinutes = remember { listOf(1L, 60L, MINUTES_PER_DAY, MINUTES_PER_WEEK) }
+    val units = stringArrayResource(R.array.backup_interval_units).toList()
+    val initialUnit = unitMinutes.indexOfLast { currentMinutes % it == 0L }.coerceAtLeast(0)
+    var amount by rememberSaveable { mutableStateOf((currentMinutes / unitMinutes[initialUnit]).toString()) }
+    var unitIndex by rememberSaveable { mutableStateOf(initialUnit) }
+
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = { Text(stringResource(R.string.calendars_auto_backup_interval)) },
+        text = {
+            Column {
+                Row(verticalAlignment = Alignment.CenterVertically) {
+                    DialogAmountField(value = amount, onValueChange = { amount = it }, placeholder = "1")
+                    Spacer(Modifier.width(12.dp))
+                    DialogUnitDropdown(label = units[unitIndex], entries = units) { unitIndex = it }
+                }
+                Spacer(Modifier.height(8.dp))
+                Text(
+                    text = stringResource(R.string.calendars_auto_backup_interval_min),
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+            }
+        },
+        confirmButton = {
+            TextButton(onClick = {
+                val value = amount.toLongOrNull()?.coerceAtLeast(1L) ?: 1L
+                onConfirm((value * unitMinutes[unitIndex]).coerceAtLeast(SettingsPrefs.MIN_BACKUP_INTERVAL))
+                onDismiss()
+            }) { Text(stringResource(R.string.reminder_custom_set)) }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) { Text(stringResource(R.string.dialog_cancel)) }
+        },
+    )
+}
+
+private const val MINUTES_PER_DAY = 1_440L
+private const val MINUTES_PER_WEEK = 10_080L
+
+/**
+ * Pick the app to open for managing a synced calendar's account. The account's
+ * own authenticator package (resolved from [AccountManager], no permission
+ * needed) handles any sync provider — DAVx5, ICSx5, Nextcloud, … — and a small
+ * curated map redirects the few cases where the authenticator isn't the app to
+ * open (Google's authenticator is Play Services, but users want the Calendar
+ * app). Falls back to the system account settings when nothing launchable is
+ * found, so the button always lands somewhere sensible.
+ */
+private fun sourceAppIntent(context: Context, accountType: String): Intent {
+    val pm = context.packageManager
+    val candidates = buildList {
+        AccountManager.get(context).authenticatorTypes
+            .firstOrNull { it.type.equals(accountType, ignoreCase = true) }
+            ?.packageName
+            ?.let { add(it) }
+        curatedSourcePackage(accountType)?.let { add(it) }
+    }
+    for (pkg in candidates) {
+        pm.getLaunchIntentForPackage(pkg)?.let { return it }
+    }
+    return Intent(Settings.ACTION_SYNC_SETTINGS)
+}
+
+/** Preferred app for account types whose authenticator isn't the app to open. */
+private fun curatedSourcePackage(accountType: String): String? = when {
+    accountType.equals("com.google", ignoreCase = true) -> "com.google.android.calendar"
+    else -> null
+}
+

app/src/main/java/de/jeanlucmakiola/calendula/ui/calendars/CalendarsViewModel.kt

@@ -0,0 +1,262 @@
+package de.jeanlucmakiola.calendula.ui.calendars
+
+import android.content.Context
+import android.content.Intent
+import android.net.Uri
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import dagger.hilt.android.lifecycle.HiltViewModel
+import dagger.hilt.android.qualifiers.ApplicationContext
+import de.jeanlucmakiola.calendula.data.backup.BackupScheduler
+import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
+import de.jeanlucmakiola.calendula.data.di.IoDispatcher
+import de.jeanlucmakiola.calendula.data.ics.IcsExporter
+import de.jeanlucmakiola.calendula.data.prefs.BackupStatus
+import de.jeanlucmakiola.calendula.data.prefs.CalendarPrefs
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import de.jeanlucmakiola.calendula.data.reminders.ReminderNotifier
+import de.jeanlucmakiola.calendula.data.reminders.SuppressedReminderStore
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.ics.IcsWriter
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.catch
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import kotlin.coroutines.cancellation.CancellationException
+import kotlin.time.Clock
+import javax.inject.Inject
+
+/**
+ * Backs the calendar manager: lists every calendar (the screen splits them into
+ * the app's own local calendars and read-only/synced ones) and creates,
+ * renames, recolors or deletes the local calendars the app owns. Write failures
+ * flip [error] so the screen can surface a one-shot message.
+ */
+@HiltViewModel
+class CalendarsViewModel @Inject constructor(
+    @ApplicationContext private val context: Context,
+    private val repository: CalendarRepository,
+    private val icsExporter: IcsExporter,
+    private val prefs: CalendarPrefs,
+    private val settingsPrefs: SettingsPrefs,
+    private val suppressedStore: SuppressedReminderStore,
+    private val notifier: ReminderNotifier,
+    @IoDispatcher private val io: CoroutineDispatcher,
+) : ViewModel() {
+
+    val calendars: StateFlow<List<CalendarSource>> =
+        repository.calendars()
+            .catch { emit(emptyList()) }
+            .flowOn(io)
+            .stateIn(
+                scope = viewModelScope,
+                started = SharingStarted.WhileSubscribed(5_000L),
+                initialValue = emptyList(),
+            )
+
+    /**
+     * Calendars the user has disabled in the app. This screen is the only
+     * surface that lists them, so it both reads the set (to dim the rows) and
+     * toggles it. Every other surface simply excludes these ids.
+     */
+    val disabledCalendarIds: StateFlow<Set<Long>> =
+        prefs.disabledCalendarIds
+            .flowOn(io)
+            .stateIn(
+                scope = viewModelScope,
+                started = SharingStarted.WhileSubscribed(5_000L),
+                initialValue = emptySet(),
+            )
+
+    /** Automatic-backup settings + last-run status, for the Backup section UI. */
+    val autoBackup: StateFlow<AutoBackupUiState> = combine(
+        settingsPrefs.autoBackupEnabled,
+        settingsPrefs.autoBackupIntervalMinutes,
+        settingsPrefs.autoBackupFolderUri,
+        settingsPrefs.autoBackupStatus,
+    ) { enabled, interval, folder, status ->
+        AutoBackupUiState(enabled, interval, folder, status)
+    }
+        .flowOn(io)
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5_000L),
+            initialValue = AutoBackupUiState(),
+        )
+
+    private val _error = MutableStateFlow(false)
+    val error: StateFlow<Boolean> = _error.asStateFlow()
+
+    fun consumeError() { _error.value = false }
+
+    private val _backupResult = MutableStateFlow<BackupResult?>(null)
+    val backupResult: StateFlow<BackupResult?> = _backupResult.asStateFlow()
+
+    fun consumeBackupResult() { _backupResult.value = null }
+
+    /**
+     * Serialise every event of the writable local calendars into the chosen SAF
+     * document [uri] as one `VCALENDAR`. Result (event count, or failure) lands
+     * in [backupResult] for a one-shot message.
+     */
+    fun exportBackup(uri: Uri) {
+        viewModelScope.launch {
+            _backupResult.value = try {
+                val count = withContext(io) {
+                    val events = repository.exportEvents()
+                    icsExporter.writeDocument(
+                        uri = uri,
+                        content = IcsWriter().writeCalendar(events, Clock.System.now()),
+                    )
+                    events.size
+                }
+                BackupResult.Success(count)
+            } catch (e: CancellationException) {
+                throw e
+            } catch (e: Exception) {
+                BackupResult.Failure
+            }
+        }
+    }
+
+    fun createCalendar(displayName: String, color: Int, description: String?) = write {
+        repository.createLocalCalendar(displayName, color, description)
+    }
+
+    fun updateCalendar(id: Long, displayName: String, color: Int, description: String?) = write {
+        repository.updateCalendar(id, displayName, color, description)
+    }
+
+    fun deleteCalendar(id: Long) = write {
+        repository.deleteCalendar(id)
+    }
+
+    /**
+     * Enable or disable a calendar app-side. Disabling removes it from every
+     * surface but Settings → Calendars (and hides its events) without touching
+     * provider data — purely a reversible Calendula-local view choice.
+     */
+    fun setDisabled(id: Long, disabled: Boolean) {
+        viewModelScope.launch {
+            val current = prefs.disabledCalendarIds.first()
+            val next = if (disabled) current + id else current - id
+            if (next != current) {
+                prefs.setDisabledCalendarIds(next)
+                if (!disabled) recoverReminders(setOf(id))
+            }
+        }
+    }
+
+    /**
+     * Enable or disable every calendar of one account in a single write — the
+     * "toggle all" affordance on an account header. Done as one set update so the
+     * per-calendar [setDisabled] calls can't race each other.
+     */
+    fun setAccountDisabled(ids: Collection<Long>, disabled: Boolean) {
+        viewModelScope.launch {
+            val current = prefs.disabledCalendarIds.first()
+            val next = if (disabled) current + ids else current - ids.toSet()
+            if (next != current) {
+                prefs.setDisabledCalendarIds(next)
+                if (!disabled) recoverReminders(current intersect ids.toSet())
+            }
+        }
+    }
+
+    /**
+     * Re-post the reminders that fired while [reEnabledIds] were disabled and are
+     * still relevant (event not yet over), then drop them from the stash. Runs
+     * after the disabled set is written, so the notifier's own disabled gate lets
+     * them through. Best-effort at re-enable time: it mirrors the receiver gates
+     * (reminders on + postable), and there is no later re-scan, so alerts left
+     * unposted because those gates are closed are simply released.
+     */
+    private suspend fun recoverReminders(reEnabledIds: Set<Long>) {
+        if (reEnabledIds.isEmpty()) return
+        val recovered = suppressedStore.recoverFor(reEnabledIds, System.currentTimeMillis())
+        if (recovered.isNotEmpty() &&
+            settingsPrefs.remindersEnabled.first() &&
+            notifier.canPost()
+        ) {
+            recovered.forEach { notifier.post(it) }
+        }
+    }
+
+    // --- Automatic backup (issue #8) ------------------------------------
+
+    fun setAutoBackupEnabled(enabled: Boolean) {
+        viewModelScope.launch {
+            settingsPrefs.setAutoBackupEnabled(enabled)
+            reschedule()
+            // Give immediate feedback when turning it on with a folder already set.
+            if (enabled && settingsPrefs.autoBackupFolderUri.first() != null) {
+                BackupScheduler.runNow(context)
+            }
+        }
+    }
+
+    fun setAutoBackupIntervalMinutes(minutes: Long) {
+        viewModelScope.launch {
+            settingsPrefs.setAutoBackupIntervalMinutes(minutes)
+            reschedule()
+        }
+    }
+
+    /** Persist the chosen destination folder (taking a durable write grant) and run once. */
+    fun setAutoBackupFolder(uri: Uri) {
+        viewModelScope.launch {
+            runCatching {
+                context.contentResolver.takePersistableUriPermission(
+                    uri,
+                    Intent.FLAG_GRANT_READ_URI_PERMISSION or Intent.FLAG_GRANT_WRITE_URI_PERMISSION,
+                )
+            }
+            settingsPrefs.setAutoBackupFolderUri(uri.toString())
+            reschedule()
+            if (settingsPrefs.autoBackupEnabled.first()) BackupScheduler.runNow(context)
+        }
+    }
+
+    private suspend fun reschedule() {
+        BackupScheduler.apply(
+            context = context,
+            enabled = settingsPrefs.autoBackupEnabled.first(),
+            intervalMinutes = settingsPrefs.autoBackupIntervalMinutes.first(),
+            hasFolder = settingsPrefs.autoBackupFolderUri.first() != null,
+        )
+    }
+
+    private inline fun write(crossinline block: suspend () -> Unit) {
+        viewModelScope.launch {
+            try {
+                block()
+            } catch (e: CancellationException) {
+                throw e
+            } catch (e: Exception) {
+                _error.value = true
+            }
+        }
+    }
+}
+
+/** Automatic-backup settings + last-run status for the Backup section. */
+data class AutoBackupUiState(
+    val enabled: Boolean = false,
+    val intervalMinutes: Long = SettingsPrefs.DEFAULT_BACKUP_INTERVAL,
+    val folderUri: String? = null,
+    val status: BackupStatus = BackupStatus(lastRun = 0L, lastSuccess = true, consecutiveFailures = 0),
+)
+
+/** Outcome of a whole-calendar backup, surfaced once to the screen. */
+sealed interface BackupResult {
+    data class Success(val eventCount: Int) : BackupResult
+    data object Failure : BackupResult
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/CalendarColors.kt

@@ -0,0 +1,55 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.CalendarMonth
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.unit.dp
+
+/**
+ * Soften a raw calendar color toward a pastel that fits the active theme.
+ *  - Keeps the hue (so users still recognise their calendars)
+ *  - Caps saturation so harsh provider colors stop screaming
+ *  - Pins value/brightness to a band that reads on both light and dark surfaces
+ */
+fun pastelize(rawArgb: Int, dark: Boolean): Color {
+    val hsv = FloatArray(3)
+    android.graphics.Color.colorToHSV(rawArgb, hsv)
+    hsv[1] = (hsv[1] * 0.6f).coerceIn(0.25f, 0.65f)
+    hsv[2] = if (dark) 0.82f else 0.72f
+    return Color(android.graphics.Color.HSVToColor(hsv))
+}
+
+/**
+ * Leading avatar for a calendar: a neutral chip holding a calendar glyph tinted
+ * in the calendar's (pastelised) colour. Shared by the calendar manager and the
+ * visibility filter so they read identically.
+ */
+@Composable
+fun CalendarColorChip(color: Int, modifier: Modifier = Modifier) {
+    val dark = isSystemInDarkTheme()
+    Box(
+        modifier = modifier
+            .size(40.dp)
+            .clip(CircleShape)
+            .background(MaterialTheme.colorScheme.surfaceContainerHighest),
+        contentAlignment = Alignment.Center,
+    ) {
+        Icon(
+            Icons.Filled.CalendarMonth,
+            contentDescription = null,
+            tint = pastelize(color, dark),
+            modifier = Modifier.size(22.dp),
+        )
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/CalendarDatePickerDialog.kt

@@ -0,0 +1,52 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.material3.DatePicker
+import androidx.compose.material3.DatePickerDialog
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.material3.rememberDatePickerState
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.res.stringResource
+import de.jeanlucmakiola.calendula.R
+import kotlinx.datetime.LocalDate
+
+/** One UTC day in milliseconds — the unit the M3 [DatePicker] speaks. */
+const val MILLIS_PER_DAY: Long = 86_400_000L
+
+/**
+ * The app's standard Material 3 date picker, opened on [initial] and reporting
+ * the chosen day through [onConfirm]. Shared by the event form (start/end date,
+ * RRULE until) and the drawer's jump-to-date action.
+ *
+ * DatePicker speaks UTC-midnight millis; epoch-day arithmetic keeps the
+ * conversion zone-proof in both directions.
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun CalendarDatePickerDialog(
+    initial: LocalDate,
+    onConfirm: (LocalDate) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    val state = rememberDatePickerState(
+        initialSelectedDateMillis = initial.toEpochDays() * MILLIS_PER_DAY,
+    )
+    DatePickerDialog(
+        onDismissRequest = onDismiss,
+        confirmButton = {
+            TextButton(
+                onClick = {
+                    state.selectedDateMillis?.let { millis ->
+                        onConfirm(LocalDate.fromEpochDays((millis / MILLIS_PER_DAY).toInt()))
+                    }
+                },
+            ) { Text(stringResource(R.string.dialog_ok)) }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) { Text(stringResource(R.string.dialog_cancel)) }
+        },
+    ) {
+        DatePicker(state = state)
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/CalendarDrawer.kt

@@ -0,0 +1,166 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.requiredSize
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.DateRange
+import androidx.compose.material.icons.filled.Settings
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.ModalDrawerSheet
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.res.colorResource
+import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.ui.filter.CalendarFilterList
+import kotlinx.datetime.LocalDate
+
+/**
+ * Navigation drawer shared by every top-level calendar screen.
+ *
+ * Uses the app's grouped-card design system (see [GroupedRow]): a branded
+ * header, the View switcher as a grouped card (the active view highlighted),
+ * a jump-to-date action, the per-calendar visibility filter (M3) inline, and a
+ * pinned Settings row. The "View" section mirrors the top-bar switcher pill —
+ * tapping a view here selects it (and closes the drawer) rather than cycling.
+ * The host screen owns the drawer state.
+ *
+ * [currentDate] seeds the jump-to-date picker (the visible day/week-start/month
+ * anchor); [onJumpToDate] navigates the active view to the chosen day.
+ */
+@Composable
+fun CalendarDrawer(
+    currentView: CalendarView,
+    currentDate: LocalDate,
+    onSelectView: (CalendarView) -> Unit,
+    onJumpToDate: (LocalDate) -> Unit,
+    onSettings: () -> Unit,
+    viewOrder: List<CalendarView> = IMPLEMENTED_VIEWS,
+) {
+    var showDatePicker by remember { mutableStateOf(false) }
+
+    ModalDrawerSheet {
+        // The whole sidebar scrolls as one — header, views, the calendar filter
+        // and Settings all flow in a single scroll container.
+        Column(
+            Modifier
+                .fillMaxHeight()
+                .verticalScroll(rememberScrollState()),
+        ) {
+            DrawerHeader()
+
+            DrawerSectionHeader(stringResource(R.string.view_section))
+            viewOrder.forEachIndexed { index, view ->
+                GroupedRow(
+                    title = stringResource(view.labelRes),
+                    position = positionOf(index, viewOrder.size),
+                    selected = view == currentView,
+                    minHeight = 56.dp,
+                    leading = { Icon(view.icon, contentDescription = null) },
+                    onClick = { onSelectView(view) },
+                )
+            }
+
+            Spacer(Modifier.height(16.dp))
+            GroupedRow(
+                title = stringResource(R.string.drawer_jump_to_date),
+                position = Position.Alone,
+                minHeight = 56.dp,
+                leading = { Icon(Icons.Filled.DateRange, contentDescription = null) },
+                onClick = { showDatePicker = true },
+            )
+
+            Spacer(Modifier.height(16.dp))
+
+            DrawerSectionHeader(stringResource(R.string.filter_title))
+            CalendarFilterList()
+
+            Spacer(Modifier.height(16.dp))
+            GroupedRow(
+                title = stringResource(R.string.month_action_settings),
+                position = Position.Alone,
+                minHeight = 56.dp,
+                leading = { Icon(Icons.Filled.Settings, contentDescription = null) },
+                onClick = onSettings,
+            )
+            Spacer(Modifier.height(8.dp))
+        }
+    }
+
+    if (showDatePicker) {
+        CalendarDatePickerDialog(
+            initial = currentDate,
+            onConfirm = {
+                showDatePicker = false
+                onJumpToDate(it)
+            },
+            onDismiss = { showDatePicker = false },
+        )
+    }
+}
+
+/** Branded header: the app-icon chip beside the app name. */
+@Composable
+private fun DrawerHeader() {
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(start = 28.dp, end = 28.dp, top = 24.dp, bottom = 16.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Box(
+            modifier = Modifier
+                .size(44.dp)
+                .clip(RoundedCornerShape(14.dp))
+                .background(colorResource(R.color.ic_launcher_background)),
+            contentAlignment = Alignment.Center,
+        ) {
+            Image(
+                painter = painterResource(R.drawable.ic_launcher_foreground),
+                contentDescription = null,
+                modifier = Modifier.requiredSize(66.dp),
+            )
+        }
+        Spacer(Modifier.width(16.dp))
+        Text(
+            text = stringResource(R.string.app_name),
+            style = MaterialTheme.typography.titleLarge,
+        )
+    }
+}
+
+/** Top-level grouping label in the drawer. Text only, so it never reads as a
+ *  tappable nav item. */
+@Composable
+private fun DrawerSectionHeader(text: String) {
+    Text(
+        text = text,
+        style = MaterialTheme.typography.titleSmall,
+        color = MaterialTheme.colorScheme.primary,
+        modifier = Modifier.padding(start = 28.dp, end = 28.dp, top = 16.dp, bottom = 8.dp),
+    )
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/CalendarFabColumn.kt

@@ -0,0 +1,58 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.scaleIn
+import androidx.compose.animation.scaleOut
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Add
+import androidx.compose.material.icons.filled.Refresh
+import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
+import androidx.compose.material3.ExtendedFloatingActionButton
+import androidx.compose.material3.FloatingActionButton
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import de.jeanlucmakiola.calendula.R
+
+/**
+ * The FAB stack shared by the three calendar views: a persistent "+" to
+ * create an event, with the jump-to-today pill appearing above it whenever
+ * the view isn't anchored on today.
+ */
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
+@Composable
+fun CalendarFabColumn(
+    todayVisible: Boolean,
+    todayText: String,
+    onToday: () -> Unit,
+    onCreate: () -> Unit,
+) {
+    Column(
+        horizontalAlignment = Alignment.End,
+        verticalArrangement = Arrangement.spacedBy(16.dp),
+    ) {
+        AnimatedVisibility(
+            visible = todayVisible,
+            enter = scaleIn(MaterialTheme.motionScheme.fastSpatialSpec()),
+            exit = scaleOut(MaterialTheme.motionScheme.fastSpatialSpec()),
+        ) {
+            ExtendedFloatingActionButton(
+                onClick = onToday,
+                icon = { Icon(Icons.Default.Refresh, contentDescription = null) },
+                text = { Text(todayText) },
+            )
+        }
+        FloatingActionButton(onClick = onCreate) {
+            Icon(
+                imageVector = Icons.Default.Add,
+                contentDescription = stringResource(R.string.event_edit_new_title),
+            )
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/CalendarFailure.kt

@@ -0,0 +1,56 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.FilledTonalButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.domain.FailureReason
+
+/**
+ * Full-screen failure state shared by every calendar screen (spec §7).
+ * One explanation line + one recovery action, never a toast.
+ */
+@Composable
+fun CalendarFailure(reason: FailureReason, onRetry: () -> Unit) {
+    val titleRes = when (reason) {
+        FailureReason.PermissionRevoked -> R.string.state_failure_permission
+        FailureReason.NoCalendarsConfigured -> R.string.state_failure_no_calendars
+        FailureReason.ProviderUnavailable -> R.string.state_failure_provider
+        FailureReason.Unknown,
+        FailureReason.EventNotFound -> R.string.state_failure_unknown
+    }
+    val actionRes = when (reason) {
+        FailureReason.NoCalendarsConfigured -> R.string.state_failure_no_calendars_action
+        FailureReason.PermissionRevoked -> R.string.state_failure_permission_action
+        else -> R.string.state_retry
+    }
+    Column(
+        modifier = Modifier
+            .fillMaxSize()
+            .padding(32.dp),
+        verticalArrangement = Arrangement.Center,
+        horizontalAlignment = Alignment.CenterHorizontally,
+    ) {
+        Text(
+            text = stringResource(titleRes),
+            style = MaterialTheme.typography.headlineSmall,
+            textAlign = TextAlign.Center,
+        )
+        Spacer(Modifier.height(24.dp))
+        FilledTonalButton(onClick = onRetry) {
+            Text(stringResource(actionRes))
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/CalendarTransitions.kt

@@ -0,0 +1,225 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import android.provider.Settings
+import androidx.activity.BackEventCompat
+import androidx.activity.compose.PredictiveBackHandler
+import androidx.compose.animation.ContentTransform
+import androidx.compose.animation.EnterTransition
+import androidx.compose.animation.ExitTransition
+import androidx.compose.animation.core.Animatable
+import androidx.compose.animation.core.FastOutSlowInEasing
+import androidx.compose.animation.core.FiniteAnimationSpec
+import androidx.compose.animation.expandVertically
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.fadeOut
+import androidx.compose.animation.shrinkVertically
+import androidx.compose.animation.slideInHorizontally
+import androidx.compose.animation.slideInVertically
+import androidx.compose.animation.slideOutHorizontally
+import androidx.compose.animation.togetherWith
+import androidx.compose.foundation.lazy.LazyItemScope
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.unit.IntOffset
+import androidx.compose.ui.unit.dp
+import kotlin.coroutines.cancellation.CancellationException
+
+/**
+ * Whether the user has asked the system to remove animations (Settings →
+ * Accessibility → "Remove animations", which sets the global animator duration
+ * scale to 0). Compose animations do *not* honour this platform flag on their
+ * own, so the shared motion helpers in this file check it and fall back to a
+ * quick cross-fade — opacity only, no spatial movement — to respect the
+ * vestibular intent of the setting while keeping state changes legible.
+ *
+ * Read once at composition; the scale changes rarely and only takes full effect
+ * after a process restart anyway.
+ */
+@Composable
+fun rememberReduceMotion(): Boolean {
+    val resolver = LocalContext.current.contentResolver
+    return remember(resolver) {
+        Settings.Global.getFloat(resolver, Settings.Global.ANIMATOR_DURATION_SCALE, 1f) == 0f
+    }
+}
+
+/**
+ * The M3 Expressive spatial spring used for the month/week slide: the *fast*
+ * spring-physics spec from the active motion scheme — snappy with a subtle
+ * springy settle, rather than a fixed easing curve.
+ *
+ * Read it in a composable scope (this helper) so it can be captured by the
+ * non-composable `AnimatedContent` transitionSpec lambda.
+ */
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
+@Composable
+fun rememberCalendarSlideSpec(): FiniteAnimationSpec<IntOffset> =
+    MaterialTheme.motionScheme.fastSpatialSpec()
+
+/**
+ * The fast effects spec from the active motion scheme, for opacity (fade)
+ * transitions. Captured in composable scope alongside [rememberCalendarSlideSpec]
+ * for use in non-composable transition lambdas and as the reduced-motion fallback.
+ */
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
+@Composable
+fun rememberCalendarFadeSpec(): FiniteAnimationSpec<Float> =
+    MaterialTheme.motionScheme.fastEffectsSpec()
+
+/**
+ * Horizontal slide for navigating between adjacent months/weeks/days.
+ *
+ * @param slideDir     +1 = forward (incoming from the right), -1 = back, 0 = jump
+ *                     (e.g. "today"); a jump reuses the forward direction.
+ * @param spec         spatial animation spec, typically [rememberCalendarSlideSpec].
+ * @param fadeSpec     effects spec for the reduced-motion fade, typically
+ *                     [rememberCalendarFadeSpec].
+ * @param reduceMotion when true, swap the directional slide for a plain cross-fade.
+ */
+fun calendarSlideTransition(
+    slideDir: Int,
+    spec: FiniteAnimationSpec<IntOffset>,
+    fadeSpec: FiniteAnimationSpec<Float>,
+    reduceMotion: Boolean,
+): ContentTransform {
+    if (reduceMotion) {
+        return fadeIn(fadeSpec).togetherWith(fadeOut(fadeSpec))
+    }
+    val dir = if (slideDir == 0) 1 else slideDir
+    return slideInHorizontally(spec) { w -> dir * w }
+        .togetherWith(slideOutHorizontally(spec) { w -> -dir * w })
+}
+
+/**
+ * Cross-fade [ContentTransform] for swapping whole screens or content blocks
+ * where there is no meaningful spatial direction (e.g. onboarding gates). Pure
+ * opacity, so it doubles as its own reduced-motion form.
+ */
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
+@Composable
+fun calendarFadeThrough(): ContentTransform {
+    val fade = MaterialTheme.motionScheme.fastEffectsSpec<Float>()
+    return fadeIn(fade).togetherWith(fadeOut(fade))
+}
+
+/**
+ * Enter transition for a vertically-revealed section (expandable rows, inline
+ * fields): height grows from the top while fading in. Under reduced motion the
+ * height growth is dropped, leaving a quick fade.
+ *
+ * Pair with [calendarCollapseExit]. This is the promoted form of the pattern
+ * originally inlined in the event edit form, so every expandable surface in the
+ * app reveals the same way.
+ */
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
+@Composable
+fun calendarExpandEnter(reduceMotion: Boolean = rememberReduceMotion()): EnterTransition {
+    val fade = fadeIn(MaterialTheme.motionScheme.fastEffectsSpec())
+    return if (reduceMotion) {
+        fade
+    } else {
+        expandVertically(MaterialTheme.motionScheme.fastSpatialSpec()) + fade
+    }
+}
+
+/** Exit counterpart to [calendarExpandEnter]: shrink + fade, or fade only under reduced motion. */
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
+@Composable
+fun calendarCollapseExit(reduceMotion: Boolean = rememberReduceMotion()): ExitTransition {
+    val fade = fadeOut(MaterialTheme.motionScheme.fastEffectsSpec())
+    return if (reduceMotion) {
+        fade
+    } else {
+        shrinkVertically(MaterialTheme.motionScheme.fastSpatialSpec()) + fade
+    }
+}
+
+/**
+ * Enter transition for content revealed by an `AnimatedContent`/`AnimatedVisibility`
+ * (e.g. search results once a query resolves): a gentle rise + fade. Reduced
+ * motion keeps the fade only.
+ */
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
+@Composable
+fun calendarItemEnter(reduceMotion: Boolean = rememberReduceMotion()): EnterTransition {
+    val fade = fadeIn(MaterialTheme.motionScheme.fastEffectsSpec())
+    return if (reduceMotion) {
+        fade
+    } else {
+        fade + slideInVertically(MaterialTheme.motionScheme.fastSpatialSpec()) { h -> h / 6 }
+    }
+}
+
+/**
+ * Shared [LazyItemScope.animateItem] wiring so list rows fade/relocate with the
+ * app's motion scheme instead of Compose's default spring. Returns a bare
+ * [Modifier] under reduced motion so rows snap into place. Requires the list to
+ * supply stable item keys.
+ */
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
+@Composable
+fun LazyItemScope.calendarAnimateItem(reduceMotion: Boolean = rememberReduceMotion()): Modifier =
+    if (reduceMotion) {
+        Modifier
+    } else {
+        Modifier.animateItem(
+            fadeInSpec = MaterialTheme.motionScheme.fastEffectsSpec(),
+            placementSpec = MaterialTheme.motionScheme.fastSpatialSpec(),
+            fadeOutSpec = MaterialTheme.motionScheme.fastEffectsSpec(),
+        )
+    }
+
+/**
+ * Standard Android predictive-back transform for a full-screen overlay: as the
+ * back gesture is dragged, the surface scales toward ~90%, shifts toward the
+ * swiped edge and rounds its corners, previewing what's behind. Completing the
+ * gesture invokes [onBack]; cancelling springs it back.
+ *
+ * A drop-in replacement for a screen's own `BackHandler(onBack)` — register it
+ * once and apply the returned [Modifier] to that screen's root so the preview
+ * respects the same back semantics. Under reduced motion the visual preview is
+ * skipped (the back still works); on API < 34 the system delivers no progress,
+ * so it degrades to a plain back.
+ */
+@Composable
+fun Modifier.predictiveBack(
+    onBack: () -> Unit,
+    enabled: Boolean = true,
+    reduceMotion: Boolean = rememberReduceMotion(),
+): Modifier {
+    val progress = remember { Animatable(0f) }
+    var fromLeftEdge by remember { mutableStateOf(true) }
+
+    PredictiveBackHandler(enabled = enabled) { events ->
+        try {
+            events.collect { event ->
+                fromLeftEdge = event.swipeEdge == BackEventCompat.EDGE_LEFT
+                progress.snapTo(FastOutSlowInEasing.transform(event.progress))
+            }
+            onBack()
+            progress.snapTo(0f)
+        } catch (_: CancellationException) {
+            progress.animateTo(0f)
+        }
+    }
+
+    if (reduceMotion) return this
+    return this.graphicsLayer {
+        val p = progress.value
+        val scale = 1f - 0.1f * p
+        scaleX = scale
+        scaleY = scale
+        translationX = (if (fromLeftEdge) 1f else -1f) * 24.dp.toPx() * p
+        shape = RoundedCornerShape(32.dp.toPx() * p)
+        clip = p > 0f
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/CalendarView.kt

@@ -0,0 +1,107 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.annotation.StringRes
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.CalendarViewDay
+import androidx.compose.material.icons.filled.CalendarViewMonth
+import androidx.compose.material.icons.filled.CalendarViewWeek
+import androidx.compose.material.icons.filled.ViewAgenda
+import androidx.compose.ui.graphics.vector.ImageVector
+import de.jeanlucmakiola.calendula.R
+
+/** The top-level calendar views the user can switch between (spec M1). */
+enum class CalendarView {
+    Month,
+    Week,
+    Day,
+    Agenda,
+}
+
+/** Switcher label, shared by the top-bar pill and the drawer's View section. */
+@get:StringRes
+val CalendarView.labelRes: Int
+    get() = when (this) {
+        CalendarView.Month -> R.string.view_month
+        CalendarView.Week -> R.string.view_week
+        CalendarView.Day -> R.string.view_day
+        CalendarView.Agenda -> R.string.view_agenda
+    }
+
+/** Leading icon for the view in the drawer's View section. */
+val CalendarView.icon: ImageVector
+    get() = when (this) {
+        CalendarView.Month -> Icons.Filled.CalendarViewMonth
+        CalendarView.Week -> Icons.Filled.CalendarViewWeek
+        CalendarView.Day -> Icons.Filled.CalendarViewDay
+        CalendarView.Agenda -> Icons.Filled.ViewAgenda
+    }
+
+/**
+ * Views that actually have a screen today. The view-switcher pill cycles
+ * through these in order.
+ */
+val IMPLEMENTED_VIEWS: List<CalendarView> =
+    listOf(CalendarView.Month, CalendarView.Week, CalendarView.Day, CalendarView.Agenda)
+
+/** Next view in [available], wrapping around. Falls back to Month if absent. */
+fun CalendarView.next(available: List<CalendarView> = IMPLEMENTED_VIEWS): CalendarView {
+    if (available.isEmpty()) return this
+    val i = available.indexOf(this)
+    if (i < 0) return available.first()
+    return available[(i + 1) % available.size]
+}
+
+/**
+ * The user's customisation of the top-bar quick-switch button (#24): which views
+ * it cycles through ([enabled]) and in what [order]. [order] always lists every
+ * implemented view — the settings screen reorders the whole set — while [cycle]
+ * is the subset the pill actually steps through, in [order]. The navigation
+ * drawer keeps its own separate order and always lists every view, so a view
+ * disabled here stays reachable there.
+ */
+data class QuickSwitchConfig(
+    val order: List<CalendarView>,
+    val enabled: Set<CalendarView>,
+) {
+    /** Views the pill steps through, in [order]. */
+    val cycle: List<CalendarView> get() = order.filter { it in enabled }
+
+    companion object {
+        /** All views, in default order, all enabled. */
+        val Default = QuickSwitchConfig(IMPLEMENTED_VIEWS, IMPLEMENTED_VIEWS.toSet())
+
+        /**
+         * Fewest views that keep the switch meaningful — a "switch" needs at
+         * least two targets, so the settings screen blocks disabling below this.
+         */
+        const val MIN_ENABLED = 2
+    }
+}
+
+/**
+ * The top-level view back stack (bottom → top): the [default] home view always
+ * sits at the bottom. Pressing back pops one level until only the home view
+ * remains, then the system exits the app. Three operations move it:
+ *
+ * - [selectView] — a lateral switch (the pill or the drawer). It keeps a visit
+ *   history so back retraces it: switching to a not-yet-visited view pushes it on
+ *   top; switching to one already in the stack pops back to it (collapsing the
+ *   loop, so the depth stays bounded by the number of distinct views). Selecting
+ *   the home view collapses to just `[default]`.
+ * - [viewBaseStack] — the stack a widget launch resets to: just `[default]` when
+ *   the widget's view is the home view, else `[default, source]`. A widget entry
+ *   starts a fresh context rather than extending in-app history.
+ * - [drillToDay] — pushes the day view on top (a date tap from the month grid or
+ *   a widget), unless the day view is already current.
+ */
+fun List<CalendarView>.selectView(target: CalendarView): List<CalendarView> {
+    val existing = indexOf(target)
+    return if (existing >= 0) take(existing + 1) else this + target
+}
+
+fun viewBaseStack(default: CalendarView, source: CalendarView): List<CalendarView> =
+    if (source == default) listOf(default) else listOf(default, source)
+
+/** Push the day view as a drill-in over the current stack (no-op if already on it). */
+fun List<CalendarView>.drillToDay(): List<CalendarView> =
+    if (lastOrNull() == CalendarView.Day) this else this + CalendarView.Day

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/ColorSwatchRow.kt

@@ -0,0 +1,69 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.border
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.ExperimentalLayoutApi
+import androidx.compose.foundation.layout.FlowRow
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Check
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.unit.dp
+
+/**
+ * A wrapping row of round colour swatches; the one matching [selected] is
+ * ringed and checked. Shared by the calendar editor and the event-colour
+ * picker so both pick a colour the same way. Swatches render through
+ * [pastelize] — the softened colour the app actually paints, not the raw hue.
+ */
+@OptIn(ExperimentalLayoutApi::class)
+@Composable
+fun ColorSwatchRow(
+    colors: List<Int>,
+    selected: Int?,
+    onSelect: (Int) -> Unit,
+    dark: Boolean,
+    modifier: Modifier = Modifier,
+) {
+    FlowRow(modifier = modifier, horizontalArrangement = Arrangement.spacedBy(12.dp)) {
+        colors.forEach { argb ->
+            val isSelected = argb == selected
+            Box(
+                contentAlignment = Alignment.Center,
+                modifier = Modifier
+                    .padding(vertical = 4.dp)
+                    .size(40.dp)
+                    .clip(CircleShape)
+                    .background(pastelize(argb, dark))
+                    .then(
+                        if (isSelected) {
+                            Modifier.border(2.dp, MaterialTheme.colorScheme.onSurface, CircleShape)
+                        } else {
+                            Modifier
+                        },
+                    )
+                    .clickable { onSelect(argb) },
+            ) {
+                if (isSelected) {
+                    Icon(
+                        Icons.Default.Check,
+                        contentDescription = null,
+                        tint = Color.Black.copy(alpha = 0.7f),
+                        modifier = Modifier.size(20.dp),
+                    )
+                }
+            }
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/DebugRibbon.kt

@@ -0,0 +1,50 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.BoxScope
+import androidx.compose.foundation.layout.offset
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.width
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.rotate
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import androidx.compose.ui.zIndex
+
+/**
+ * A Flutter-style "DEBUG" corner ribbon, drawn across the top-right corner of
+ * the app. Deliberately a stark, un-themed marker (not a product component) so a
+ * debug build is unmistakable at a glance — gate it on `BuildConfig.DEBUG` at the
+ * call site so it never reaches a release build. Non-interactive: it's a plain
+ * label with no pointer handler, so taps fall through to whatever is beneath it.
+ *
+ * Drop it in as the last child of a full-screen [androidx.compose.foundation.layout.Box]
+ * so it overlays the UI.
+ */
+@Composable
+fun BoxScope.DebugRibbon() {
+    Text(
+        text = "DEBUG",
+        color = Color.White,
+        fontSize = 10.sp,
+        fontWeight = FontWeight.Bold,
+        letterSpacing = 1.sp,
+        textAlign = TextAlign.Center,
+        modifier = Modifier
+            .align(Alignment.TopEnd)
+            .zIndex(1f)
+            // Push the band out so its midline crosses the very corner, then
+            // rotate it to the classic 45° ribbon.
+            .offset(x = 36.dp, y = 24.dp)
+            .rotate(45f)
+            .background(Color(0xFFB23B00))
+            .width(140.dp)
+            .padding(vertical = 2.dp),
+    )
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/DialogControls.kt

@@ -0,0 +1,94 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.ArrowDropDown
+import androidx.compose.material3.DropdownMenu
+import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.unit.dp
+
+/**
+ * Tonal 3-digit number input shared by the custom reminder/recurrence steps and
+ * the reminder pickers — the app's [InlineTextField] over a tonal surface, so it
+ * matches the card/grouped-row design language (not Material's outlined field).
+ */
+@Composable
+fun DialogAmountField(
+    value: String,
+    onValueChange: (String) -> Unit,
+    placeholder: String,
+) {
+    // surfaceContainerHighest — the picker/dialog sits on surfaceContainerHigh,
+    // so anything lower vanishes.
+    Surface(
+        color = MaterialTheme.colorScheme.surfaceContainerHighest,
+        shape = RoundedCornerShape(12.dp),
+    ) {
+        InlineTextField(
+            value = value,
+            onValueChange = { text ->
+                if (text.length <= 3 && text.all(Char::isDigit)) onValueChange(text)
+            },
+            placeholder = placeholder,
+            textStyle = MaterialTheme.typography.titleMedium,
+            keyboardType = KeyboardType.Number,
+            modifier = Modifier
+                .width(72.dp)
+                .padding(horizontal = 14.dp, vertical = 12.dp),
+        )
+    }
+}
+
+/** Tonal dropdown trigger + menu shared by the custom reminder/recurrence steps and pickers. */
+@Composable
+fun DialogUnitDropdown(
+    label: String,
+    entries: List<String>,
+    onPick: (Int) -> Unit,
+) {
+    var open by remember { mutableStateOf(false) }
+    Box {
+        Surface(
+            color = MaterialTheme.colorScheme.surfaceContainerHighest,
+            shape = RoundedCornerShape(12.dp),
+            onClick = { open = true },
+        ) {
+            Row(
+                verticalAlignment = Alignment.CenterVertically,
+                modifier = Modifier.padding(start = 14.dp, end = 8.dp, top = 12.dp, bottom = 12.dp),
+            ) {
+                Text(text = label, style = MaterialTheme.typography.titleMedium)
+                Spacer(Modifier.width(4.dp))
+                Icon(imageVector = Icons.Default.ArrowDropDown, contentDescription = null)
+            }
+        }
+        DropdownMenu(expanded = open, onDismissRequest = { open = false }) {
+            entries.forEachIndexed { index, entry ->
+                DropdownMenuItem(
+                    text = { Text(entry) },
+                    onClick = {
+                        onPick(index)
+                        open = false
+                    },
+                )
+            }
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/EventFormFieldVisuals.kt

@@ -0,0 +1,44 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.annotation.StringRes
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.Notes
+import androidx.compose.material.icons.filled.EventAvailable
+import androidx.compose.material.icons.filled.Lock
+import androidx.compose.material.icons.filled.Notifications
+import androidx.compose.material.icons.filled.Palette
+import androidx.compose.material.icons.filled.People
+import androidx.compose.material.icons.filled.Place
+import androidx.compose.material.icons.filled.Repeat
+import androidx.compose.ui.graphics.vector.ImageVector
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.domain.EventFormField
+
+/**
+ * The shared label and icon for each optional [EventFormField]. Both the event
+ * editor (which shows these fields) and the settings screen (which toggles their
+ * defaults) draw from this one mapping, so a field reads the same wherever it
+ * appears.
+ */
+@StringRes
+fun eventFormFieldLabel(field: EventFormField): Int = when (field) {
+    EventFormField.Location -> R.string.event_detail_location
+    EventFormField.Description -> R.string.event_detail_description
+    EventFormField.Reminders -> R.string.event_detail_reminders
+    EventFormField.Recurrence -> R.string.event_detail_recurrence
+    EventFormField.Availability -> R.string.event_edit_availability
+    EventFormField.Visibility -> R.string.event_edit_visibility
+    EventFormField.Color -> R.string.event_edit_color
+    EventFormField.Attendees -> R.string.event_edit_attendees
+}
+
+fun eventFormFieldIcon(field: EventFormField): ImageVector = when (field) {
+    EventFormField.Location -> Icons.Default.Place
+    EventFormField.Description -> Icons.AutoMirrored.Filled.Notes
+    EventFormField.Reminders -> Icons.Default.Notifications
+    EventFormField.Recurrence -> Icons.Default.Repeat
+    EventFormField.Availability -> Icons.Default.EventAvailable
+    EventFormField.Visibility -> Icons.Default.Lock
+    EventFormField.Color -> Icons.Default.Palette
+    EventFormField.Attendees -> Icons.Default.People
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/GroupedList.kt

@@ -0,0 +1,245 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.animation.core.animateDpAsState
+import androidx.compose.foundation.background
+import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.interaction.collectIsPressedAsState
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.ColumnScope
+import androidx.compose.foundation.layout.RowScope
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.consumeWindowInsets
+import androidx.compose.foundation.layout.heightIn
+import androidx.compose.foundation.layout.imePadding
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.LargeTopAppBar
+import androidx.compose.material3.ListItem
+import androidx.compose.material3.ListItemDefaults
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TopAppBar
+import androidx.compose.material3.TopAppBarDefaults
+import androidx.compose.material3.rememberTopAppBarState
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.input.nestedscroll.nestedScroll
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+import de.jeanlucmakiola.calendula.R
+
+/**
+ * Position of a row within a grouped list, after the Android-15 settings
+ * pattern: a run of rows shares one rounded container, with full corners at the
+ * group's outer edges and small corners between, separated by small gaps.
+ */
+enum class Position { Top, Middle, Bottom, Alone }
+
+/** Maps an index within a group of [count] rows to its [Position]. */
+fun positionOf(index: Int, count: Int): Position = when {
+    count <= 1 -> Position.Alone
+    index == 0 -> Position.Top
+    index == count - 1 -> Position.Bottom
+    else -> Position.Middle
+}
+
+/**
+ * The app's standard full-screen list scaffold. By default a collapsing
+ * [LargeTopAppBar] whose title shrinks into the bar (next to the back button) as
+ * the content scrolls — used by Settings and the calendar manager, where the
+ * large header sets the page. Content is a scrollable column that feeds the
+ * toolbar via nested scroll.
+ *
+ * Set [largeTopBar] to false for a pinned, single-line [TopAppBar] instead: the
+ * title sits in the bar from the start, with no expanded header to scroll past.
+ * Preferred for selection pickers, where the tall header is just wasted space
+ * above the options.
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun CollapsingScaffold(
+    title: String,
+    onBack: () -> Unit,
+    modifier: Modifier = Modifier,
+    largeTopBar: Boolean = true,
+    snackbarHost: @Composable () -> Unit = {},
+    actions: @Composable RowScope.() -> Unit = {},
+    content: @Composable ColumnScope.() -> Unit,
+) {
+    val scrollBehavior = if (largeTopBar) {
+        TopAppBarDefaults.exitUntilCollapsedScrollBehavior(rememberTopAppBarState())
+    } else {
+        TopAppBarDefaults.pinnedScrollBehavior(rememberTopAppBarState())
+    }
+    Scaffold(
+        modifier = modifier
+            .predictiveBack(onBack = onBack)
+            .fillMaxSize()
+            .background(MaterialTheme.colorScheme.surface)
+            .nestedScroll(scrollBehavior.nestedScrollConnection),
+        topBar = {
+            val navigationIcon = @Composable {
+                IconButton(onClick = onBack) {
+                    Icon(
+                        Icons.AutoMirrored.Filled.ArrowBack,
+                        contentDescription = stringResource(R.string.settings_back),
+                    )
+                }
+            }
+            val colors = TopAppBarDefaults.topAppBarColors(
+                scrolledContainerColor = MaterialTheme.colorScheme.surface,
+            )
+            if (largeTopBar) {
+                LargeTopAppBar(
+                    title = { Text(title) },
+                    navigationIcon = navigationIcon,
+                    actions = actions,
+                    scrollBehavior = scrollBehavior,
+                    colors = colors,
+                )
+            } else {
+                TopAppBar(
+                    title = { Text(title) },
+                    navigationIcon = navigationIcon,
+                    actions = actions,
+                    scrollBehavior = scrollBehavior,
+                    colors = colors,
+                )
+            }
+        },
+        snackbarHost = snackbarHost,
+    ) { innerPadding ->
+        Column(
+            modifier = Modifier
+                .padding(innerPadding)
+                // Mark the scaffold's system-bar insets as consumed so the
+                // imePadding below adds only the keyboard height beyond them
+                // (max, not sum) — otherwise the nav-bar inset double-counts and
+                // leaves an empty strip above the keyboard.
+                .consumeWindowInsets(innerPadding)
+                .fillMaxSize()
+                // Paint the surface across the full area before imePadding carves
+                // into it, so any sliver above the keyboard reads as surface — not
+                // the dialog window's black — during the IME animation.
+                .background(MaterialTheme.colorScheme.surface)
+                // Shrink the scroll viewport by the keyboard inset so a focused
+                // field (e.g. the custom-reminder amount) can scroll into view.
+                .imePadding()
+                .verticalScroll(rememberScrollState())
+                .padding(top = 8.dp, bottom = 24.dp),
+            content = content,
+        )
+    }
+}
+
+/**
+ * One row in a grouped list: an M3 [ListItem] over a tonal [Surface] whose
+ * corner radii come from its [position] (so a run of rows reads as a single
+ * rounded card). Corners round further on press. A null [onClick] makes the
+ * row non-interactive (e.g. read-only entries). [dimmed] fades the headline and
+ * summary to the M3 disabled emphasis while leaving the [trailing] control at
+ * full opacity — for rows that are present but switched off.
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun GroupedRow(
+    title: String,
+    position: Position,
+    modifier: Modifier = Modifier,
+    summary: String? = null,
+    selected: Boolean = false,
+    dimmed: Boolean = false,
+    container: Color? = null,
+    minHeight: Dp = 72.dp,
+    // The 2.dp separation between rows in a run. Suppressed by the reorderable
+    // list, which owns uniform spacing itself so every slot has the same pitch.
+    gapBelow: Boolean = true,
+    leading: @Composable (() -> Unit)? = null,
+    trailing: @Composable (() -> Unit)? = null,
+    onClick: (() -> Unit)? = null,
+) {
+    val interaction = remember { MutableInteractionSource() }
+    val pressed by interaction.collectIsPressedAsState()
+    val full by animateDpAsState(if (pressed) 36.dp else 22.dp, label = "fullCorner")
+    val small by animateDpAsState(if (pressed) 36.dp else 6.dp, label = "smallCorner")
+    val shape = when (position) {
+        Position.Alone -> RoundedCornerShape(full)
+        Position.Top -> RoundedCornerShape(
+            topStart = full, topEnd = full, bottomStart = small, bottomEnd = small,
+        )
+        Position.Middle -> RoundedCornerShape(small)
+        Position.Bottom -> RoundedCornerShape(
+            topStart = small, topEnd = small, bottomStart = full, bottomEnd = full,
+        )
+    }
+    val gap = when {
+        !gapBelow -> Modifier
+        position == Position.Top || position == Position.Middle -> Modifier.padding(bottom = 2.dp)
+        else -> Modifier
+    }
+    val itemColors = if (selected) {
+        ListItemDefaults.colors(
+            containerColor = Color.Transparent,
+            headlineColor = MaterialTheme.colorScheme.onSecondaryContainer,
+            leadingIconColor = MaterialTheme.colorScheme.onSecondaryContainer,
+            supportingColor = MaterialTheme.colorScheme.onSecondaryContainer,
+            trailingIconColor = MaterialTheme.colorScheme.onSecondaryContainer,
+        )
+    } else if (dimmed) {
+        // M3 disabled emphasis (0.38α) on the text/leading; the trailing control
+        // stays full-opacity so the toggle reads as live even on a faded row.
+        val muted = MaterialTheme.colorScheme.onSurface.copy(alpha = 0.38f)
+        ListItemDefaults.colors(
+            containerColor = Color.Transparent,
+            headlineColor = muted,
+            leadingIconColor = muted,
+            supportingColor = muted,
+        )
+    } else {
+        ListItemDefaults.colors(containerColor = Color.Transparent)
+    }
+    val item: @Composable () -> Unit = {
+        ListItem(
+            headlineContent = { Text(title) },
+            supportingContent = summary?.let { text -> { Text(text) } },
+            leadingContent = leading,
+            trailingContent = trailing,
+            colors = itemColors,
+            modifier = Modifier.heightIn(min = minHeight),
+        )
+    }
+    val base = modifier
+        .fillMaxWidth()
+        .padding(horizontal = 16.dp)
+        .then(gap)
+    val containerColor = when {
+        selected -> MaterialTheme.colorScheme.secondaryContainer
+        container != null -> container
+        else -> MaterialTheme.colorScheme.surfaceContainerHigh
+    }
+    if (onClick != null) {
+        Surface(
+            onClick = onClick,
+            color = containerColor,
+            shape = shape,
+            interactionSource = interaction,
+            modifier = base,
+        ) { item() }
+    } else {
+        Surface(color = containerColor, shape = shape, modifier = base) { item() }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/HourLines.kt

@@ -0,0 +1,38 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.runtime.staticCompositionLocalOf
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.drawBehind
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.graphics.Color
+
+/**
+ * Whether the week/day timeline draws an hour separator line, from the
+ * `showHourLines` preference. Provided once at the app root (like
+ * [LocalUse24HourFormat]) so the timeline reads it without ViewModel plumbing.
+ * Defaults to off — the historical clean look.
+ */
+val LocalShowHourLines = staticCompositionLocalOf { false }
+
+/**
+ * Draw a faint separator line at the top of each hour (1..23) when [show] is
+ * true. Applied to a day column's content so each line sits over the column's
+ * background but beneath the event blocks. [hourHeightPx] is one hour's pixel
+ * height; [color] is resolved by the caller from the theme.
+ */
+fun Modifier.hourSeparatorLines(show: Boolean, hourHeightPx: Float, color: Color): Modifier =
+    if (!show) {
+        this
+    } else {
+        drawBehind {
+            for (hour in 1 until 24) {
+                val y = hour * hourHeightPx
+                drawLine(
+                    color = color,
+                    start = Offset(0f, y),
+                    end = Offset(size.width, y),
+                    strokeWidth = 1f,
+                )
+            }
+        }
+    }

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/InlineTextField.kt

@@ -0,0 +1,86 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.text.BasicTextField
+import androidx.compose.foundation.text.KeyboardActions
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.SolidColor
+import androidx.compose.ui.graphics.isSpecified
+import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.text.input.ImeAction
+import androidx.compose.ui.text.input.KeyboardCapitalization
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.unit.dp
+
+/**
+ * The app's borderless text input: no underline, no outline, just the tonal
+ * card behind it. This is the standard input across the app — we deliberately
+ * don't use Material's outlined/filled text fields, so anything that takes text
+ * (the event form, the calendar manager, dialogs) uses this inside a tonal
+ * [androidx.compose.material3.Surface].
+ */
+@Composable
+fun InlineTextField(
+    value: String,
+    onValueChange: (String) -> Unit,
+    placeholder: String,
+    modifier: Modifier = Modifier
+        .fillMaxWidth()
+        .padding(vertical = 4.dp),
+    textStyle: TextStyle = MaterialTheme.typography.titleMedium,
+    singleLine: Boolean = true,
+    minLines: Int = 1,
+    enabled: Boolean = true,
+    keyboardType: KeyboardType = KeyboardType.Text,
+    capitalization: KeyboardCapitalization = KeyboardCapitalization.None,
+    imeAction: ImeAction = ImeAction.Default,
+    /** Invoked when the IME action key (e.g. Done) is pressed. */
+    onImeAction: (() -> Unit)? = null,
+) {
+    val resolvedStyle = textStyle.copy(
+        color = when {
+            // A disabled field reads as dimmed, like a locked value.
+            !enabled -> MaterialTheme.colorScheme.onSurfaceVariant
+            textStyle.color.isSpecified -> textStyle.color
+            else -> MaterialTheme.colorScheme.onSurface
+        },
+    )
+    BasicTextField(
+        value = value,
+        onValueChange = onValueChange,
+        enabled = enabled,
+        textStyle = resolvedStyle,
+        singleLine = singleLine,
+        minLines = minLines,
+        keyboardOptions = KeyboardOptions(
+            keyboardType = keyboardType,
+            capitalization = capitalization,
+            imeAction = imeAction,
+        ),
+        keyboardActions = onImeAction?.let { action ->
+            KeyboardActions(onAny = { action() })
+        } ?: KeyboardActions.Default,
+        cursorBrush = SolidColor(MaterialTheme.colorScheme.primary),
+        decorationBox = { innerTextField ->
+            Box {
+                if (value.isEmpty()) {
+                    // Clearly fainter than typed text, so a hint never reads as
+                    // prefilled content.
+                    Text(
+                        text = placeholder,
+                        style = resolvedStyle,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = 0.5f),
+                    )
+                }
+                innerTextField()
+            }
+        },
+        modifier = modifier,
+    )
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/LocaleSupport.kt

@@ -0,0 +1,20 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.compose.ui.platform.LocalConfiguration
+import androidx.core.os.ConfigurationCompat
+import java.util.Locale
+
+/**
+ * Current display [Locale], read observably from [LocalConfiguration] so the UI
+ * recomposes after a locale change (lint: NonObservableLocale). Used for
+ * weekday/month name formatting.
+ */
+@Composable
+fun currentLocale(): Locale {
+    val configuration = LocalConfiguration.current
+    return remember(configuration) {
+        ConfigurationCompat.getLocales(configuration).get(0) ?: Locale.getDefault()
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/NowLine.kt

@@ -0,0 +1,90 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.offset
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.State
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+import kotlinx.coroutines.delay
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Clock
+import kotlin.time.Instant
+
+private val DotSize = 8.dp
+private val LineThickness = 2.dp
+
+/**
+ * Current wall-clock instant that updates once a minute, re-aligning to each
+ * minute boundary (rather than ticking a fixed 60 s) so it never drifts toward
+ * the middle of a minute. Drives the "now" line in the day/week grids.
+ */
+@Composable
+fun rememberCurrentMinute(): State<Instant> {
+    val instant = remember { mutableStateOf(Clock.System.now()) }
+    LaunchedEffect(Unit) {
+        while (true) {
+            val now = Clock.System.now()
+            instant.value = now
+            delay(60_000L - now.toEpochMilliseconds() % 60_000L)
+        }
+    }
+    return instant
+}
+
+/**
+ * A thin "current time" indicator — a leading dot plus a line — drawn across a
+ * day column. Positioned on the same [hourHeight] scale the event blocks use so
+ * it lines up with the grid, and refreshed each minute. Renders nothing unless
+ * the wall clock is on [date]; callers mount it only for the column showing
+ * today, so the per-minute tick runs on a single column.
+ */
+@Composable
+fun NowLine(
+    date: LocalDate,
+    hourHeight: Dp,
+    modifier: Modifier = Modifier,
+) {
+    val now by rememberCurrentMinute()
+    val local = now.toLocalDateTime(TimeZone.currentSystemDefault())
+    if (local.date != date) return
+
+    val minutes = local.hour * 60 + local.minute
+    val top = hourHeight * (minutes / 60f)
+    val color = MaterialTheme.colorScheme.primary
+    Box(
+        modifier = modifier
+            .fillMaxWidth()
+            .height(DotSize)
+            .offset(y = top - DotSize / 2),
+        contentAlignment = Alignment.CenterStart,
+    ) {
+        Box(
+            modifier = Modifier
+                .fillMaxWidth()
+                .height(LineThickness)
+                .background(color),
+        )
+        // The dot anchors the line to the gutter edge, mirroring the standard
+        // calendar "now" marker; drawn after the line so it sits on top.
+        Box(
+            modifier = Modifier
+                .size(DotSize)
+                .background(color, CircleShape),
+        )
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/OptionCard.kt

@@ -0,0 +1,94 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.isSpecified
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.unit.dp
+
+/**
+ * The app's standard pick in a selection dialog: a full-width tonal card,
+ * optionally with a leading icon and a supporting line; the selected option
+ * is highlighted. Stack with 8dp gaps inside an AlertDialog — this is the
+ * only sanctioned selection-modal style (no radio rows, no bare text lists).
+ */
+@Composable
+fun OptionCard(
+    label: String,
+    onClick: () -> Unit,
+    modifier: Modifier = Modifier,
+    icon: ImageVector? = null,
+    /** Icon tint override, e.g. a calendar colour; unspecified follows selection. */
+    iconTint: Color = Color.Unspecified,
+    supportingText: String? = null,
+    selected: Boolean = false,
+    /** Label colour override, e.g. primary for an emphasised "Custom" entry. */
+    labelColor: Color = Color.Unspecified,
+) {
+    val contentColor = if (selected) {
+        MaterialTheme.colorScheme.onSecondaryContainer
+    } else {
+        MaterialTheme.colorScheme.onSurface
+    }
+    Surface(
+        onClick = onClick,
+        color = if (selected) {
+            MaterialTheme.colorScheme.secondaryContainer
+        } else {
+            MaterialTheme.colorScheme.surfaceContainerHighest
+        },
+        shape = RoundedCornerShape(12.dp),
+        modifier = modifier.fillMaxWidth(),
+    ) {
+        Row(
+            verticalAlignment = Alignment.CenterVertically,
+            modifier = Modifier.padding(horizontal = 16.dp, vertical = 14.dp),
+        ) {
+            if (icon != null) {
+                Icon(
+                    imageVector = icon,
+                    contentDescription = null,
+                    tint = when {
+                        iconTint.isSpecified -> iconTint
+                        selected -> MaterialTheme.colorScheme.onSecondaryContainer
+                        else -> MaterialTheme.colorScheme.onSurfaceVariant
+                    },
+                    modifier = Modifier.size(20.dp),
+                )
+                Spacer(Modifier.width(12.dp))
+            }
+            Column {
+                Text(
+                    text = label,
+                    style = MaterialTheme.typography.titleMedium,
+                    color = if (labelColor.isSpecified) labelColor else contentColor,
+                )
+                if (supportingText != null) {
+                    Text(
+                        text = supportingText,
+                        style = MaterialTheme.typography.bodySmall,
+                        color = if (selected) {
+                            MaterialTheme.colorScheme.onSecondaryContainer.copy(alpha = 0.8f)
+                        } else {
+                            MaterialTheme.colorScheme.onSurfaceVariant
+                        },
+                    )
+                }
+            }
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/PastEvents.kt

@@ -0,0 +1,16 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.runtime.compositionLocalOf
+import kotlin.time.Instant
+
+/**
+ * The cut-off instant before which a calendar event counts as "completed" and is
+ * drawn dimmed in the month/week grids — i.e. the current wall-clock minute when
+ * the "dim completed events" setting is on, or `null` when it is off (nothing
+ * dims). Provided per grid screen so only the event chips that read it recompose
+ * as the minute ticks, mirroring [LocalShowHourLines] / [LocalUse24HourFormat].
+ */
+val LocalDimCutoff = compositionLocalOf<Instant?> { null }
+
+/** Opacity applied to a completed/past event chip when it is dimmed. */
+const val EventDimAlpha = 0.4f

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/Picker.kt

@@ -0,0 +1,504 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.ColumnScope
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Check
+import androidx.compose.material3.Checkbox
+import androidx.compose.material3.FilledTonalButton
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.SegmentedButton
+import androidx.compose.material3.SegmentedButtonDefaults
+import androidx.compose.material3.SingleChoiceSegmentedButtonRow
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import android.view.WindowManager
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.SideEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalView
+import androidx.compose.ui.res.pluralStringResource
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.window.Dialog
+import androidx.compose.ui.window.DialogProperties
+import androidx.compose.ui.window.DialogWindowProvider
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.data.prefs.CalendarReminderOverride
+import de.jeanlucmakiola.calendula.ui.agenda.AgendaRange
+
+/**
+ * Shared full-screen scaffold for selection pickers: a full-bleed [Dialog] that
+ * reuses the app's [CollapsingScaffold] (back button + full width), but with a
+ * pinned single-line title rather than the large collapsing header — a picker is
+ * a short list, so the tall header would only be empty space to scroll past.
+ * [content] places the connected grouped rows; selecting one calls [onDismiss].
+ */
+@Composable
+fun FullScreenPicker(
+    title: String,
+    onDismiss: () -> Unit,
+    content: @Composable ColumnScope.() -> Unit,
+) {
+    Dialog(
+        onDismissRequest = onDismiss,
+        properties = DialogProperties(
+            usePlatformDefaultWidth = false,
+            decorFitsSystemWindows = false,
+        ),
+    ) {
+        // The dialog window pans by default when the keyboard opens, which —
+        // combined with the content's own imePadding — leaves a fixed black gap
+        // above the keyboard. Switch it to ADJUST_NOTHING so the window stays
+        // full-screen and imePadding alone lifts the focused field.
+        val view = LocalView.current
+        SideEffect {
+            (view.parent as? DialogWindowProvider)?.window
+                ?.setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_NOTHING)
+        }
+        CollapsingScaffold(
+            title = title,
+            onBack = onDismiss,
+            largeTopBar = false,
+            content = content,
+        )
+    }
+}
+
+/**
+ * General single-select picker, full-screen: each option is a connected grouped
+ * row and the current one carries a check. Drop-in for the former dialog
+ * (theme, week start, language, …).
+ */
+@Composable
+fun <T> OptionPicker(
+    title: String,
+    options: List<T>,
+    selected: T,
+    label: @Composable (T) -> String,
+    onSelect: (T) -> Unit,
+    onDismiss: () -> Unit,
+    header: (@Composable ColumnScope.() -> Unit)? = null,
+) {
+    FullScreenPicker(title = title, onDismiss = onDismiss) {
+        header?.invoke(this)
+        options.forEachIndexed { index, option ->
+            val isSelected = option == selected
+            GroupedRow(
+                title = label(option),
+                position = positionOf(index, options.size),
+                selected = isSelected,
+                trailing = if (isSelected) {
+                    { SelectedCheck() }
+                } else {
+                    null
+                },
+                onClick = {
+                    onSelect(option)
+                    onDismiss()
+                },
+            )
+        }
+    }
+}
+
+/**
+ * Reminder-default picker, full-screen and **multi-select**: each [presets]
+ * lead time (plus any chosen custom value) is a checkbox row that toggles
+ * independently, so a default can carry several reminders ("1 week before" *and*
+ * "on the day"). Two exclusive checkmark rows sit above the list: an explicit
+ * "No reminder" (both pickers, so the empty state stays visible and reachable)
+ * and, for a per-calendar picker ([allowInherit]), "Use default reminder", which
+ * defers to the global default. Clearing the last checked time reverts to "Use
+ * default" on a per-calendar picker (so an accidental toggle-undo can't silently
+ * wipe the calendar's default) and to explicit [CalendarReminderOverride.None]
+ * on the global default (where empty legitimately means no reminder). A "Custom"
+ * row expands an inline number field plus a unit selector to add an arbitrary
+ * lead time to the set. Changes apply live via [onSelect]; the user leaves via
+ * back.
+ */
+@Composable
+fun ReminderDefaultPicker(
+    title: String,
+    presets: List<Int>,
+    selected: CalendarReminderOverride,
+    allowInherit: Boolean,
+    onSelect: (CalendarReminderOverride) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    // Optimistic local state: once the user edits, the chosen override is
+    // authoritative while the picker is open, so quick successive toggles compose
+    // on each other instead of racing the round-trip through the settings flow
+    // (which would drop a toggle made before the previous write echoes back).
+    var current by remember { mutableStateOf(selected) }
+    // Whether the user has toggled anything yet. Until then, [current] keeps
+    // mirroring [selected]: a picker that first composed against the settings
+    // flow's initialValue (empty — reachable after process-death restore straight
+    // onto the Notifications page, before the CalendarProvider-gated combine
+    // resolves) then adopts the real stored default instead of persisting empty
+    // on the first tap. After the first edit, local state is authoritative.
+    var userEdited by remember { mutableStateOf(false) }
+    LaunchedEffect(selected) {
+        if (!userEdited) current = selected
+    }
+    val inherits = current is CalendarReminderOverride.Inherit
+    val isNone = current is CalendarReminderOverride.None
+    val selectedMinutes = (current as? CalendarReminderOverride.Minutes)?.minutes.orEmpty()
+    // Custom (non-preset) lead times seen this session, so unchecking one keeps
+    // its row (unchecked) until the picker closes instead of vanishing mid-tap,
+    // which would strand a hand-entered value with no way to re-check it.
+    val seenCustom = remember { mutableSetOf<Int>() }
+    seenCustom += selectedMinutes.filter { it !in presets }
+    // Presets plus every custom value seen this session, each as its own row.
+    val rows = presets + seenCustom.sorted()
+
+    var customExpanded by rememberSaveable { mutableStateOf(false) }
+    var amountText by rememberSaveable { mutableStateOf("") }
+    var unit by rememberSaveable { mutableStateOf(ReminderUnit.Minutes) }
+
+    fun apply(override: CalendarReminderOverride) {
+        userEdited = true
+        current = override
+        onSelect(override)
+    }
+    fun emit(minutes: List<Int>) = apply(reminderOverrideForMinutes(minutes, allowInherit))
+    fun toggle(minute: Int) =
+        emit(if (minute in selectedMinutes) selectedMinutes - minute else selectedMinutes + minute)
+
+    FullScreenPicker(title = title, onDismiss = onDismiss) {
+        // Exclusive choices in their own group above the multi-select list, since
+        // each is mutually exclusive with picking specific times: "use default"
+        // (per-calendar only) and an explicit "no reminder" (both pickers, so the
+        // empty state stays visible and deliberately reachable).
+        if (allowInherit) {
+            GroupedRow(
+                title = stringResource(R.string.reminder_use_default),
+                position = Position.Top,
+                selected = inherits,
+                trailing = if (inherits) {
+                    { SelectedCheck() }
+                } else {
+                    null
+                },
+                onClick = { apply(CalendarReminderOverride.Inherit) },
+            )
+        }
+        GroupedRow(
+            title = stringResource(R.string.reminder_none),
+            position = if (allowInherit) Position.Bottom else Position.Alone,
+            selected = isNone,
+            trailing = if (isNone) {
+                { SelectedCheck() }
+            } else {
+                null
+            },
+            onClick = { apply(CalendarReminderOverride.None) },
+        )
+        Spacer(Modifier.height(24.dp))
+        val rowCount = rows.size + 1 // + the custom row
+        rows.forEachIndexed { index, minute ->
+            val checked = minute in selectedMinutes
+            GroupedRow(
+                title = reminderLeadTimeLabel(minute),
+                position = positionOf(index, rowCount),
+                selected = checked,
+                trailing = { Checkbox(checked = checked, onCheckedChange = { toggle(minute) }) },
+                onClick = { toggle(minute) },
+            )
+        }
+        // When expanded, the Custom row connects downward into the editor card
+        // so the two read as one grouped container (the per-calendar pattern).
+        GroupedRow(
+            title = stringResource(R.string.event_edit_reminder_custom),
+            position = if (customExpanded) Position.Top else positionOf(rows.size, rowCount),
+            onClick = { customExpanded = !customExpanded },
+        )
+        AnimatedVisibility(
+            visible = customExpanded,
+            enter = calendarExpandEnter(),
+            exit = calendarCollapseExit(),
+        ) {
+            CustomReminderEditor(
+                amountText = amountText,
+                onAmountChange = { amountText = it },
+                unit = unit,
+                onUnitChange = { unit = it },
+                onConfirm = { minutes ->
+                    emit(selectedMinutes + minutes)
+                    amountText = ""
+                    customExpanded = false
+                },
+            )
+        }
+    }
+}
+
+/**
+ * The override a lead-time set maps to when emitted from [ReminderDefaultPicker].
+ * A non-empty set is [CalendarReminderOverride.Minutes]; an empty set (the last
+ * time was unchecked) reverts to [CalendarReminderOverride.Inherit] on a
+ * per-calendar picker ([allowInherit]) so an accidental toggle-undo can't
+ * silently wipe the calendar's default, and to explicit
+ * [CalendarReminderOverride.None] on the global default (where empty legitimately
+ * means no reminder). Pure so it can be unit-tested.
+ */
+internal fun reminderOverrideForMinutes(
+    minutes: List<Int>,
+    allowInherit: Boolean,
+): CalendarReminderOverride {
+    val norm = minutes.distinct().sorted()
+    return when {
+        norm.isNotEmpty() -> CalendarReminderOverride.Minutes(norm)
+        allowInherit -> CalendarReminderOverride.Inherit
+        else -> CalendarReminderOverride.None
+    }
+}
+
+/**
+ * The expanded "Custom" lead-time editor: a tonal card connected to the Custom
+ * row above it (matching the grouped-row system, so the two read as one
+ * container). An amount field with a live preview of the resulting lead time, a
+ * single-choice unit toggle, and a tonal confirm enabled only for a valid
+ * 1–999 amount. [onConfirm] receives the final lead time in minutes.
+ */
+@Composable
+private fun CustomReminderEditor(
+    amountText: String,
+    onAmountChange: (String) -> Unit,
+    unit: ReminderUnit,
+    onUnitChange: (ReminderUnit) -> Unit,
+    onConfirm: (Int) -> Unit,
+) {
+    val amount = amountText.toIntOrNull()?.takeIf { it in 1..999 }
+    Surface(
+        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+        // A Position.Bottom shape: tight top corners meeting the row, full bottom.
+        shape = RoundedCornerShape(topStart = 6.dp, topEnd = 6.dp, bottomStart = 22.dp, bottomEnd = 22.dp),
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(horizontal = 16.dp),
+    ) {
+        Column(
+            modifier = Modifier.padding(16.dp),
+            verticalArrangement = Arrangement.spacedBy(16.dp),
+        ) {
+            // Unit toggle first so it stays visible above the keyboard once the
+            // amount field (the bottom row) is focused and scrolled into view.
+            SingleChoiceSegmentedButtonRow(modifier = Modifier.fillMaxWidth()) {
+                ReminderUnit.entries.forEachIndexed { index, entry ->
+                    SegmentedButton(
+                        selected = unit == entry,
+                        onClick = { onUnitChange(entry) },
+                        shape = SegmentedButtonDefaults.itemShape(index, ReminderUnit.entries.size),
+                        label = { Text(stringResource(reminderUnitLabel(entry))) },
+                    )
+                }
+            }
+            // Amount, a live preview of the lead time it resolves to, and Set —
+            // all on one row, sitting just above the keyboard.
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                DialogAmountField(
+                    value = amountText,
+                    onValueChange = onAmountChange,
+                    placeholder = "10",
+                )
+                Spacer(Modifier.width(16.dp))
+                Text(
+                    text = amount?.let { reminderLeadTimeLabel(it * unit.minutesFactor) }
+                        ?: stringResource(R.string.reminder_custom_amount),
+                    style = MaterialTheme.typography.bodyLarge,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    modifier = Modifier.weight(1f),
+                )
+                Spacer(Modifier.width(16.dp))
+                FilledTonalButton(
+                    onClick = { amount?.let { onConfirm(it * unit.minutesFactor) } },
+                    enabled = amount != null,
+                ) {
+                    Text(stringResource(R.string.reminder_custom_set))
+                }
+            }
+        }
+    }
+}
+
+/** A short explanatory paragraph shown under a picker's title, above the rows. */
+@Composable
+private fun PickerDescription(text: String) {
+    Text(
+        text = text,
+        style = MaterialTheme.typography.bodyMedium,
+        color = MaterialTheme.colorScheme.onSurfaceVariant,
+        modifier = Modifier.padding(horizontal = 16.dp, vertical = 8.dp),
+    )
+}
+
+@Composable
+private fun SelectedCheck() {
+    Icon(
+        imageVector = Icons.Default.Check,
+        contentDescription = null,
+        tint = MaterialTheme.colorScheme.primary,
+    )
+}
+
+/**
+ * Agenda-range picker, full-screen. Two grouped lists — the calendar-aligned
+ * options (today / this week / this month) and the rolling windows (next 7 / 30
+ * days), with a "Custom" row that expands an inline day-count editor (1–365).
+ * Mirrors [ReminderDefaultPicker]'s custom-expand pattern.
+ */
+@Composable
+fun AgendaRangePicker(
+    title: String,
+    description: String,
+    selected: AgendaRange,
+    onSelect: (AgendaRange) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    val calendarAligned = listOf(AgendaRange.Day, AgendaRange.ThisWeek, AgendaRange.ThisMonth)
+    val rolling = listOf(AgendaRange.Week, AgendaRange.Month)
+    val rollingRowCount = rolling.size + 1 // + the custom row
+    val customSelected = selected is AgendaRange.Custom
+
+    var customExpanded by rememberSaveable { mutableStateOf(false) }
+    var amountText by rememberSaveable {
+        mutableStateOf((selected as? AgendaRange.Custom)?.days?.toString() ?: "")
+    }
+
+    val rangeRow: @Composable (AgendaRange, Position) -> Unit = { option, position ->
+        val isSelected = option == selected
+        GroupedRow(
+            title = agendaRangeLabel(option),
+            position = position,
+            selected = isSelected,
+            trailing = if (isSelected) {
+                { SelectedCheck() }
+            } else {
+                null
+            },
+            onClick = {
+                onSelect(option)
+                onDismiss()
+            },
+        )
+    }
+
+    FullScreenPicker(title = title, onDismiss = onDismiss) {
+        PickerDescription(description)
+
+        // Calendar-aligned windows.
+        calendarAligned.forEachIndexed { index, option ->
+            rangeRow(option, positionOf(index, calendarAligned.size))
+        }
+
+        Spacer(Modifier.height(12.dp))
+
+        // Rolling windows + custom.
+        rolling.forEachIndexed { index, option ->
+            rangeRow(option, positionOf(index, rollingRowCount))
+        }
+        GroupedRow(
+            title = if (customSelected) {
+                agendaRangeLabel(selected)
+            } else {
+                stringResource(R.string.agenda_range_custom)
+            },
+            position = if (customExpanded) Position.Top else positionOf(rolling.size, rollingRowCount),
+            selected = customSelected,
+            trailing = if (customSelected) {
+                { SelectedCheck() }
+            } else {
+                null
+            },
+            onClick = { customExpanded = !customExpanded },
+        )
+        AnimatedVisibility(
+            visible = customExpanded,
+            enter = calendarExpandEnter(),
+            exit = calendarCollapseExit(),
+        ) {
+            CustomDaysEditor(
+                amountText = amountText,
+                onAmountChange = { amountText = it },
+                onConfirm = { days ->
+                    onSelect(AgendaRange.Custom(days))
+                    onDismiss()
+                },
+            )
+        }
+    }
+}
+
+/** The expanded "Custom" day-count editor: an amount field (1–365) and Set. */
+@Composable
+private fun CustomDaysEditor(
+    amountText: String,
+    onAmountChange: (String) -> Unit,
+    onConfirm: (Int) -> Unit,
+) {
+    val days = amountText.toIntOrNull()
+        ?.takeIf { it in AgendaRange.MIN_CUSTOM_DAYS..AgendaRange.MAX_CUSTOM_DAYS }
+    Surface(
+        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+        shape = RoundedCornerShape(topStart = 6.dp, topEnd = 6.dp, bottomStart = 22.dp, bottomEnd = 22.dp),
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(horizontal = 16.dp),
+    ) {
+        Row(
+            modifier = Modifier.padding(16.dp),
+            verticalAlignment = Alignment.CenterVertically,
+        ) {
+            DialogAmountField(
+                value = amountText,
+                onValueChange = onAmountChange,
+                placeholder = "30",
+            )
+            Spacer(Modifier.width(16.dp))
+            Text(
+                text = days?.let { pluralStringResource(R.plurals.agenda_range_days, it, it) }
+                    ?: stringResource(R.string.agenda_range_custom_hint),
+                style = MaterialTheme.typography.bodyLarge,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = Modifier.weight(1f),
+            )
+            Spacer(Modifier.width(16.dp))
+            FilledTonalButton(
+                onClick = { days?.let(onConfirm) },
+                enabled = days != null,
+            ) {
+                Text(stringResource(R.string.reminder_custom_set))
+            }
+        }
+    }
+}
+
+/** Human label for an [AgendaRange] (used by the picker rows and settings summary). */
+@Composable
+fun agendaRangeLabel(range: AgendaRange): String = when (range) {
+    AgendaRange.Day -> stringResource(R.string.agenda_range_day)
+    AgendaRange.ThisWeek -> stringResource(R.string.agenda_range_this_week)
+    AgendaRange.ThisMonth -> stringResource(R.string.agenda_range_this_month)
+    AgendaRange.Week -> stringResource(R.string.agenda_range_week)
+    AgendaRange.Month -> stringResource(R.string.agenda_range_month)
+    is AgendaRange.Custom -> pluralStringResource(R.plurals.agenda_range_days, range.days, range.days)
+}
+

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/RecurrenceText.kt

@@ -0,0 +1,126 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import android.icu.text.ListFormatter
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.AnnotatedString
+import androidx.compose.ui.text.SpanStyle
+import androidx.compose.ui.text.buildAnnotatedString
+import androidx.compose.ui.text.font.FontStyle
+import de.jeanlucmakiola.calendula.R
+import java.time.DayOfWeek
+import java.time.format.DateTimeFormatter
+import java.time.format.FormatStyle
+import java.time.format.TextStyle as JavaTextStyle
+import java.util.Locale
+
+/**
+ * Humanise an RFC 5545 RRULE into a localized phrase, e.g.
+ * "Every week on Tue and Thu until 31 Dec 2026" or "Every day, 10 times".
+ * Falls back to a generic label for rules we don't render in full (ordinal
+ * monthly/yearly BYDAY, etc.). Shared by the detail screen and the edit
+ * form's repeat card.
+ */
+@Composable
+fun recurrenceText(rrule: String, locale: Locale): AnnotatedString {
+    val parts = rrule.removePrefix("RRULE:").split(';').mapNotNull { token ->
+        val eq = token.indexOf('=')
+        if (eq <= 0) null else token.substring(0, eq).uppercase() to token.substring(eq + 1)
+    }.toMap()
+
+    val freq = parts["FREQ"]?.uppercase()
+    val interval = parts["INTERVAL"]?.toIntOrNull() ?: 1
+    val base = when (freq) {
+        "DAILY" -> if (interval == 1) stringResource(R.string.recurrence_daily)
+        else stringResource(R.string.recurrence_every_n_days, interval)
+        "WEEKLY" -> if (interval == 1) stringResource(R.string.recurrence_weekly)
+        else stringResource(R.string.recurrence_every_n_weeks, interval)
+        "MONTHLY" -> if (interval == 1) stringResource(R.string.recurrence_monthly)
+        else stringResource(R.string.recurrence_every_n_months, interval)
+        "YEARLY" -> if (interval == 1) stringResource(R.string.recurrence_yearly)
+        else stringResource(R.string.recurrence_every_n_years, interval)
+        else -> return AnnotatedString(stringResource(R.string.event_detail_recurring))
+    }
+
+    // Weekly + BYDAY → "<base> on <days>"; other BYDAY forms keep just the base.
+    // The day names + their joined block are tracked so only the names (not the
+    // commas/conjunction) can be italicised in the final string.
+    val byDay = parts["BYDAY"]
+    var dayNames: List<String>? = null
+    var joinedDays: String? = null
+    val main = if (freq == "WEEKLY" && !byDay.isNullOrBlank()) {
+        val days = byDay.split(',').mapNotNull { rruleDayName(it.trim(), locale) }
+        if (days.isNotEmpty()) {
+            val joined = ListFormatter.getInstance(locale).format(days)
+            dayNames = days
+            joinedDays = joined
+            stringResource(R.string.recurrence_on_days, base, joined)
+        } else {
+            base
+        }
+    } else {
+        base
+    }
+
+    // End bound: UNTIL (a date) takes precedence over COUNT (a number of times).
+    val until = parts["UNTIL"]?.let { parseUntilDate(it, locale) }
+    val count = parts["COUNT"]?.toIntOrNull()
+    val full = when {
+        until != null -> stringResource(R.string.recurrence_with_until, main, until)
+        count != null -> stringResource(R.string.recurrence_with_count, main, count)
+        else -> main
+    }
+
+    return buildAnnotatedString {
+        append(full)
+        val names = dayNames
+        val joined = joinedDays
+        if (names != null && joined != null) {
+            // Italicise each day name within the joined block only — leaving the
+            // separators and conjunction ("und"/"and") in the regular style.
+            val regionStart = full.indexOf(joined)
+            if (regionStart >= 0) {
+                val regionEnd = regionStart + joined.length
+                var cursor = regionStart
+                for (name in names) {
+                    val at = full.indexOf(name, cursor)
+                    if (at in regionStart until regionEnd) {
+                        addStyle(SpanStyle(fontStyle = FontStyle.Italic), at, at + name.length)
+                        cursor = at + name.length
+                    }
+                }
+            }
+        }
+    }
+}
+
+/** Map an RRULE BYDAY token (e.g. "TU" or "2TH") to a localized short weekday name. */
+private fun rruleDayName(token: String, locale: Locale): String? {
+    val dow = when (token.takeLast(2).uppercase()) {
+        "MO" -> DayOfWeek.MONDAY
+        "TU" -> DayOfWeek.TUESDAY
+        "WE" -> DayOfWeek.WEDNESDAY
+        "TH" -> DayOfWeek.THURSDAY
+        "FR" -> DayOfWeek.FRIDAY
+        "SA" -> DayOfWeek.SATURDAY
+        "SU" -> DayOfWeek.SUNDAY
+        else -> return null
+    }
+    return dow.getDisplayName(JavaTextStyle.SHORT, locale)
+}
+
+/** Parse an RRULE UNTIL value ("20261231" or "20261231T235959Z") to a localized date. */
+private fun parseUntilDate(raw: String, locale: Locale): String? {
+    val digits = raw.takeWhile { it.isDigit() }
+    if (digits.length < 8) return null
+    return try {
+        val date = java.time.LocalDate.of(
+            digits.substring(0, 4).toInt(),
+            digits.substring(4, 6).toInt(),
+            digits.substring(6, 8).toInt(),
+        )
+        DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM).withLocale(locale).format(date)
+    } catch (e: Exception) {
+        null
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/ReminderFormatting.kt

@@ -0,0 +1,46 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.annotation.StringRes
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.res.pluralStringResource
+import androidx.compose.ui.res.stringResource
+import de.jeanlucmakiola.calendula.R
+
+/** Common reminder lead times offered as quick picks in the form and settings. */
+val REMINDER_PRESETS = listOf(0, 10, 30, 60, 1_440)
+
+/** The unit of a custom reminder lead time; [minutesFactor] converts to minutes. */
+enum class ReminderUnit(val minutesFactor: Int) {
+    Minutes(1),
+    Hours(60),
+    Days(1_440),
+    Weeks(10_080),
+}
+
+@StringRes
+fun reminderUnitLabel(unit: ReminderUnit): Int = when (unit) {
+    ReminderUnit.Minutes -> R.string.reminder_unit_minutes
+    ReminderUnit.Hours -> R.string.reminder_unit_hours
+    ReminderUnit.Days -> R.string.reminder_unit_days
+    ReminderUnit.Weeks -> R.string.reminder_unit_weeks
+}
+
+/**
+ * Humanise a reminder lead time (minutes before the event start) into one
+ * line: "Default reminder" (negative = the provider default), "At time of
+ * event" (0), "10 minutes before", "1 hour before", … Shared by the detail
+ * screen, the event form and the default-reminder settings so the wording
+ * never drifts.
+ */
+@Composable
+fun reminderLeadTimeLabel(minutes: Int): String = when {
+    minutes < 0 -> stringResource(R.string.reminder_default)
+    minutes == 0 -> stringResource(R.string.reminder_at_time)
+    minutes % 10_080 == 0 ->
+        pluralStringResource(R.plurals.reminder_weeks, minutes / 10_080, minutes / 10_080)
+    minutes % 1_440 == 0 ->
+        pluralStringResource(R.plurals.reminder_days, minutes / 1_440, minutes / 1_440)
+    minutes % 60 == 0 ->
+        pluralStringResource(R.plurals.reminder_hours, minutes / 60, minutes / 60)
+    else -> pluralStringResource(R.plurals.reminder_minutes, minutes, minutes)
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/ReorderableColumn.kt

@@ -0,0 +1,183 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.animation.core.Animatable
+import androidx.compose.animation.core.Spring
+import androidx.compose.animation.core.animateFloatAsState
+import androidx.compose.animation.core.snap
+import androidx.compose.animation.core.spring
+import androidx.compose.animation.core.tween
+import androidx.compose.foundation.gestures.detectDragGestures
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.derivedStateOf
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableFloatStateOf
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.zIndex
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.launch
+import kotlin.math.roundToInt
+
+/** Uniform row height for [ReorderableColumn]; a fixed pitch keeps drag maths exact. */
+val ReorderableRowHeight: Dp = 64.dp
+private val RowGap: Dp = 2.dp
+
+/**
+ * A vertical list whose rows can be dragged into a new order by their handle.
+ *
+ * Built for the short, fixed grouped-card lists in Settings (#24) — no external
+ * dependency and no [androidx.compose.foundation.lazy.LazyColumn] (the settings
+ * screens are a single [androidx.compose.foundation.verticalScroll] column, which
+ * can't nest a scrolling list). Rows are a fixed [ReorderableRowHeight] with a
+ * uniform gap, so a row's target slot is simply how many whole pitches it has
+ * been dragged. The held row follows the finger while the others slide out of
+ * its way (animated); on release the order is committed immediately with a
+ * single [onReorder] call, then the held row eases into its new slot as a
+ * purely visual settle — safe to interrupt with another drag, since the
+ * commit itself never waits on it.
+ *
+ * [rowContent] receives the [Position] for the row's place in the order (to reuse
+ * [GroupedRow]'s card shaping — pass `gapBelow = false` there, this owns spacing)
+ * and a `dragHandle` [Modifier] to attach to the element that starts a drag.
+ */
+@Composable
+fun <T> ReorderableColumn(
+    items: List<T>,
+    keyOf: (T) -> Any,
+    onReorder: (List<T>) -> Unit,
+    modifier: Modifier = Modifier,
+    rowContent: @Composable (item: T, position: Position, dragHandle: Modifier, isDragging: Boolean) -> Unit,
+) {
+    val pitchPx = with(LocalDensity.current) { (ReorderableRowHeight + RowGap).toPx() }
+    val scope = rememberCoroutineScope()
+
+    // Local working copy; re-seeded when the incoming list changes (including the
+    // echo of our own committed order).
+    var order by remember(items) { mutableStateOf(items) }
+    var draggedKey by remember { mutableStateOf<Any?>(null) }
+    // Live translation of the held row from its slot (px); also drives the
+    // release settle — re-based onto the row's new slot once the order commits
+    // (see onDragEnd), then eased down to zero.
+    var dragOffset by remember { mutableFloatStateOf(0f) }
+    // The running release/cancel settle, cancelled if a new drag pre-empts it.
+    // Purely visual — the order commit (see onDragEnd) never depends on it.
+    var settleJob by remember { mutableStateOf<Job?>(null) }
+
+    val draggedIndex = draggedKey?.let { key -> order.indexOfFirst { keyOf(it) == key }.takeIf { it >= 0 } }
+    // Whole slots dragged → the slot the held row currently hovers over. Derived
+    // so recomposition only fires when the *target slot* actually changes, not on
+    // every dragged pixel: dragOffset moves every frame during a drag, but the
+    // held row's own translation is already applied in the draw phase via
+    // graphicsLayer below, so only the neighbours' shift (which depends on this)
+    // needs to recompose, and only when a slot boundary is actually crossed.
+    // (Read as a plain val, not `by`, below: a delegated property has a custom
+    // getter and Kotlin won't smart-cast it in the `when` over `targetIndex` in
+    // the loop, so the derived value is captured into a real local instead.)
+    val targetIndex = remember(items, pitchPx) {
+        derivedStateOf {
+            val idx = draggedKey?.let { key -> order.indexOfFirst { keyOf(it) == key }.takeIf { it >= 0 } }
+            idx?.let { (it + (dragOffset / pitchPx).roundToInt()).coerceIn(0, order.lastIndex) }
+        }
+    }.value
+
+    Column(modifier, verticalArrangement = Arrangement.spacedBy(RowGap)) {
+        order.forEachIndexed { index, item ->
+            val key = keyOf(item)
+            val isDragged = key == draggedKey
+
+            // Slide neighbours by one pitch to open the gap the held row will drop
+            // into. Snap (not animate) once idle, so committing the new order — which
+            // moves each row's slot — doesn't visibly fight a lingering animation.
+            val shift = when {
+                draggedIndex == null || targetIndex == null || isDragged -> 0f
+                index in (draggedIndex + 1)..targetIndex -> -pitchPx
+                index in targetIndex until draggedIndex -> pitchPx
+                else -> 0f
+            }
+            val animatedShift by animateFloatAsState(
+                targetValue = shift,
+                animationSpec = if (draggedKey != null) spring(stiffness = Spring.StiffnessMediumLow) else snap(),
+                label = "reorderShift",
+            )
+
+            val dragHandle = Modifier.pointerInput(key) {
+                detectDragGestures(
+                    onDragStart = {
+                        settleJob?.cancel()
+                        draggedKey = key
+                        dragOffset = 0f
+                    },
+                    onDrag = { change, amount ->
+                        change.consume()
+                        dragOffset += amount.y
+                    },
+                    onDragEnd = {
+                        val from = order.indexOfFirst { keyOf(it) == key }
+                        if (from < 0) return@detectDragGestures
+                        val to = (from + (dragOffset / pitchPx).roundToInt()).coerceIn(0, order.lastIndex)
+                        if (to != from) {
+                            // Commit synchronously and unconditionally, before the settle
+                            // animation below runs — the commit must not depend on that
+                            // coroutine reaching its end, or a new drag starting within the
+                            // ~160ms settle window would cancel it and silently revert an
+                            // already-finished reorder.
+                            order = order.toMutableList().apply { add(to, removeAt(from)) }
+                            onReorder(order)
+                            // The row now lays out at slot `to` instead of `from`; re-base
+                            // the live offset onto that new slot (same visual position,
+                            // expressed relative to the new one) so the settle below eases
+                            // it the rest of the way instead of jumping.
+                            dragOffset -= (to - from) * pitchPx
+                        }
+                        settleJob = scope.launch {
+                            // Purely visual from here: ease the held row onto its slot, then
+                            // release the drag state. Safe to cancel — the order was already
+                            // committed above.
+                            Animatable(dragOffset).animateTo(0f, tween(160)) { dragOffset = value }
+                            draggedKey = null
+                            dragOffset = 0f
+                        }
+                    },
+                    onDragCancel = {
+                        settleJob = scope.launch {
+                            Animatable(dragOffset).animateTo(0f, tween(160)) { dragOffset = value }
+                            draggedKey = null
+                            dragOffset = 0f
+                        }
+                    },
+                )
+            }
+
+            Box(
+                Modifier
+                    .height(ReorderableRowHeight)
+                    .zIndex(if (isDragged) 1f else 0f)
+                    .graphicsLayer {
+                        translationY = if (isDragged) dragOffset else animatedShift
+                        if (isDragged) {
+                            scaleX = 1.02f
+                            scaleY = 1.02f
+                            shadowElevation = 8.dp.toPx()
+                            shape = RoundedCornerShape(20.dp)
+                            clip = false
+                        }
+                    },
+            ) {
+                rowContent(item, positionOf(index, order.size), dragHandle, isDragged)
+            }
+        }
+    }
+}