release: cut v1.2.0 — event creation

Version bumped to 1.2.0 / 9. No code changes beyond the version — 1.2.0 is
the create slice: event form, "+" FAB on every view, last-used-calendar
preselect, provider-correct all-day storage. CHANGELOG [1.2.0] carries the
details; ROADMAP/STATE mark slice v1.2 shipped.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.gitea/workflows/ci.yaml

@@ -6,7 +6,11 @@ on:
       - '**'
     tags-ignore:
       - '**'
-  pull_request:
+
+# Cancel superseded runs on the same branch.
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
 
 jobs:
   ci:
@@ -26,30 +30,25 @@ jobs:
 
       - name: Setup Android SDK
         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
+        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: 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
         uses: actions/cache@v4
         with:
@@ -63,16 +62,19 @@ jobs:
       - name: Grant execute permission for gradlew
         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
+        run: ./gradlew lintDebug
 
       - name: Unit tests
-        run: ./gradlew testDebugUnitTest --no-daemon
+        run: ./gradlew testDebugUnitTest
 
       - name: Assemble debug APK
-        run: ./gradlew assembleDebug --no-daemon
+        run: ./gradlew assembleDebug
 
       - name: Trivy filesystem scan
+        if: github.ref == 'refs/heads/main'
         run: |
           set -e
           SUDO=""

.gitea/workflows/release.yaml

@@ -24,16 +24,33 @@ jobs:
 
       - name: Setup Android SDK
         uses: android-actions/setup-android@v3
+        with:
+          packages: ''
+
+      - 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: Grant execute permission for gradlew
         run: chmod +x ./gradlew
 
@@ -42,10 +59,10 @@ jobs:
       # any tag-resolved drift (e.g. version code substitution issues).
 
       - name: Unit tests
-        run: ./gradlew testDebugUnitTest --no-daemon
+        run: ./gradlew testDebugUnitTest
 
       - name: Assemble debug APK (sanity)
-        run: ./gradlew assembleDebug --no-daemon
+        run: ./gradlew assembleDebug
 
   build-and-deploy:
     needs: ci
@@ -65,16 +82,33 @@ jobs:
 
       - name: Setup Android SDK
         uses: android-actions/setup-android@v3
+        with:
+          packages: ''
+
+      - 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
@@ -121,7 +155,7 @@ jobs:
         run: chmod +x ./gradlew
 
       - name: Build release APK
-        run: ./gradlew assembleRelease --no-daemon
+        run: ./gradlew assembleRelease
 
       - name: Setup F-Droid Server Tools
         run: |

.planning/ROADMAP.md

@@ -53,11 +53,18 @@ after v0.6 (full event read) plus the onboarding-screen polish pass.
 - ~~Redesign the initial grant-access (permission) screen~~ — **done**
   (Material 3 Expressive onboarding, shipped in v0.6.0 / v1.0.0)
 
-## v2.0 — Write Support
+## v2.0 — Write Support (in progress)
 
-- Event create / edit / delete via `CalendarContract` writes
+Delivered in four releasable slices (plan:
-- Quick-add sheet
+`docs/superpowers/plans/2026-06-11-03-write-support.md`). The V1 spec is a
-- Conflict UX (event modified externally during edit)
+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) |
+| v1.3 | Edit event — shared form, series edit, reminders, simple recurrence picker | planned |
+| v2.0 | Quick-add, occurrence edit, conflict dialog, polish, release | planned |
 
 ## v3.0 — Power-User Features
 

.planning/STATE.md

@@ -4,10 +4,11 @@
 
 ## Status
 
-**Milestone:** v1.0.0 — First public release (shipped 2026-06-11)
+**Milestone:** v2.0 — Write support (milestone 2, in progress)
-**Phase:** V1 is complete and released. All screens done, the read model
+**Phase:** v1.2.0 shipped 2026-06-11 (create event), after v1.1.0 the same
-surfaces every readable `CalendarContract` field, and the onboarding screen
+day (write foundation + delete). Milestone 2 runs in four slices
-got its Material 3 Expressive polish pass. Next horizon is v2.0 (write support)
+(`docs/superpowers/plans/2026-06-11-03-write-support.md`); next up is v1.3
+(edit event).
 
 ## Progress
 
@@ -28,7 +29,22 @@ got its Material 3 Expressive polish pass. Next horizon is v2.0 (write support)
   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
+
 ## Next
 
-1. v1.0.0 released — monitor the F-Droid build/publish
+1. v1.3 — edit event: reuse the form, series edit, reminder edit, simple
-2. Plan v2.0 (write support: create / edit / delete, quick-add, conflict UX)
+   recurrence picker
+2. Monitor the F-Droid build/publish for v1.1.0 / v1.2.0

CHANGELOG.md

@@ -7,6 +7,49 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [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

app/build.gradle.kts

@@ -23,8 +23,8 @@ android {
         applicationId = "de.jeanlucmakiola.calendula"
         minSdk = 29
         targetSdk = 36
-        versionCode = 7
+        versionCode = 9
-        versionName = "1.0.0"
+        versionName = "1.2.0"
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
     }

app/src/main/AndroidManifest.xml

@@ -3,6 +3,7 @@
     xmlns:tools="http://schemas.android.com/tools">
 
     <uses-permission android:name="android.permission.READ_CALENDAR" />
+    <uses-permission android:name="android.permission.WRITE_CALENDAR" />
 
     <application
         android:name=".CalendulaApp"

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

@@ -2,6 +2,7 @@ package de.jeanlucmakiola.calendula.data.calendar
 
 import android.content.ContentResolver
 import android.content.ContentUris
+import android.content.ContentValues
 import android.content.Context
 import android.database.ContentObserver
 import android.database.Cursor
@@ -12,8 +13,10 @@ import dagger.hilt.android.qualifiers.ApplicationContext
 import de.jeanlucmakiola.calendula.domain.Attendee
 import de.jeanlucmakiola.calendula.domain.CalendarSource
 import de.jeanlucmakiola.calendula.domain.EventDetail
+import de.jeanlucmakiola.calendula.domain.EventForm
 import de.jeanlucmakiola.calendula.domain.EventInstance
 import de.jeanlucmakiola.calendula.domain.Reminder
+import java.time.ZoneId
 import javax.inject.Inject
 import javax.inject.Singleton
 
@@ -29,6 +32,19 @@ interface CalendarDataSource {
     fun calendars(): List<CalendarSource>
     fun instances(beginMillis: Long, endMillis: Long): List<EventInstance>
     fun eventDetail(eventId: Long): EventDetail?
+
+    /** Insert a new event; returns the new `Events._ID`. */
+    fun insertEvent(form: EventForm): Long
+
+    /** Delete the whole event (for recurring events: the entire series). */
+    fun deleteEvent(eventId: Long)
+
+    /**
+     * Cancel a single occurrence of a recurring event by inserting a
+     * cancelled exception at [beginMillis] (the occurrence's `Instances.BEGIN`).
+     */
+    fun deleteOccurrence(eventId: Long, beginMillis: Long)
+
     fun registerChangeListener(listener: () -> Unit)
     fun unregisterChangeListener(listener: () -> Unit)
 }
@@ -74,6 +90,50 @@ class AndroidCalendarDataSource @Inject constructor(
         }
     }
 
+    override fun insertEvent(form: EventForm): Long {
+        val times = form.toWriteTimes(ZoneId.systemDefault())
+        val values = ContentValues().apply {
+            put(
+                CalendarContract.Events.CALENDAR_ID,
+                requireNotNull(form.calendarId) { "EventForm.calendarId is required" },
+            )
+            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.DTEND, times.dtEndMillis)
+            put(CalendarContract.Events.EVENT_TIMEZONE, times.timezone)
+            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) }
+        }
+        val uri = resolver.insert(CalendarContract.Events.CONTENT_URI, values)
+            ?: throw WriteFailedException("insert event into calendar id=${form.calendarId}")
+        return ContentUris.parseId(uri)
+    }
+
+    override fun deleteEvent(eventId: Long) {
+        val deleted = resolver.delete(
+            ContentUris.withAppendedId(CalendarContract.Events.CONTENT_URI, eventId),
+            null, null,
+        )
+        if (deleted == 0) throw WriteFailedException("delete event id=$eventId")
+    }
+
+    override fun deleteOccurrence(eventId: Long, beginMillis: Long) {
+        // A cancelled exception row hides exactly this occurrence; the sync
+        // adapter turns it into an EXDATE/cancelled VEVENT upstream.
+        val values = ContentValues().apply {
+            put(CalendarContract.Events.ORIGINAL_INSTANCE_TIME, beginMillis)
+            put(CalendarContract.Events.STATUS, CalendarContract.Events.STATUS_CANCELED)
+        }
+        val uri = ContentUris.withAppendedId(
+            CalendarContract.Events.CONTENT_EXCEPTION_URI, eventId,
+        )
+        resolver.insert(uri, values)
+            ?: throw WriteFailedException("cancel occurrence event id=$eventId begin=$beginMillis")
+    }
+
     override fun registerChangeListener(listener: () -> Unit) {
         val obs = object : ContentObserver(Handler(Looper.getMainLooper())) {
             override fun onChange(selfChange: Boolean) {

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

@@ -1,5 +1,6 @@
 package de.jeanlucmakiola.calendula.data.calendar
 
+import android.provider.CalendarContract
 import de.jeanlucmakiola.calendula.domain.CalendarSource
 
 internal fun ColumnReader.toCalendarSource(): CalendarSource = CalendarSource(
@@ -10,4 +11,6 @@ internal fun ColumnReader.toCalendarSource(): CalendarSource = CalendarSource(
     accountType = getString(CalendarProjection.IDX_ACCOUNT_TYPE).orEmpty(),
     color = getInt(CalendarProjection.IDX_COLOR),
     isVisibleInSystem = getInt(CalendarProjection.IDX_VISIBLE) != 0,
+    canModifyContents = getInt(CalendarProjection.IDX_ACCESS_LEVEL) >=
+        CalendarContract.Calendars.CAL_ACCESS_CONTRIBUTOR,
 )

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

@@ -2,6 +2,7 @@ package de.jeanlucmakiola.calendula.data.calendar
 
 import de.jeanlucmakiola.calendula.domain.CalendarSource
 import de.jeanlucmakiola.calendula.domain.EventDetail
+import de.jeanlucmakiola.calendula.domain.EventForm
 import de.jeanlucmakiola.calendula.domain.EventInstance
 import kotlinx.coroutines.flow.Flow
 import kotlin.time.Instant
@@ -10,7 +11,20 @@ interface CalendarRepository {
     fun calendars(): Flow<List<CalendarSource>>
     fun instances(range: ClosedRange<Instant>): Flow<List<EventInstance>>
     suspend fun eventDetail(eventId: Long): EventDetail
+
+    /** Create a new event from a validated form; returns the new `Events._ID`. */
+    suspend fun createEvent(form: 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)
 }
 
 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

@@ -4,6 +4,7 @@ import de.jeanlucmakiola.calendula.data.di.IoDispatcher
 import de.jeanlucmakiola.calendula.data.prefs.CalendarPrefs
 import de.jeanlucmakiola.calendula.domain.CalendarSource
 import de.jeanlucmakiola.calendula.domain.EventDetail
+import de.jeanlucmakiola.calendula.domain.EventForm
 import de.jeanlucmakiola.calendula.domain.EventInstance
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.flow.Flow
@@ -68,6 +69,18 @@ class CalendarRepositoryImpl @Inject constructor(
     override suspend fun eventDetail(eventId: Long): EventDetail = withContext(io) {
         dataSource.eventDetail(eventId) ?: throw NoSuchEventException(eventId)
     }
+
+    override suspend fun createEvent(form: EventForm): Long = withContext(io) {
+        dataSource.insertEvent(form)
+    }
+
+    override suspend fun deleteEvent(eventId: Long) = withContext(io) {
+        dataSource.deleteEvent(eventId)
+    }
+
+    override suspend fun deleteOccurrence(eventId: Long, beginMillis: Long) = withContext(io) {
+        dataSource.deleteOccurrence(eventId, beginMillis)
+    }
 }
 
 private fun <T> Flow<Unit>.reQuery(block: suspend () -> T): Flow<T> = flow {

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

@@ -0,0 +1,35 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import de.jeanlucmakiola.calendula.domain.EventForm
+import kotlinx.datetime.toJavaLocalDate
+import kotlinx.datetime.toJavaLocalDateTime
+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,
+    )
+}

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

@@ -10,6 +10,7 @@ internal object CalendarProjection {
         CalendarContract.Calendars.ACCOUNT_TYPE,
         CalendarContract.Calendars.CALENDAR_COLOR,
         CalendarContract.Calendars.VISIBLE,
+        CalendarContract.Calendars.CALENDAR_ACCESS_LEVEL,
     )
 
     const val IDX_ID = 0
@@ -18,6 +19,7 @@ internal object CalendarProjection {
     const val IDX_ACCOUNT_TYPE = 3
     const val IDX_COLOR = 4
     const val IDX_VISIBLE = 5
+    const val IDX_ACCESS_LEVEL = 6
 }
 
 internal object InstanceProjection {

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 +39,20 @@ class CalendarPrefs @Inject constructor(
         }
     }
 
+    /**
+     * 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 LAST_USED_CALENDAR_KEY = longPreferencesKey("last_used_calendar_id")
     }
 }

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

@@ -0,0 +1,35 @@
+package de.jeanlucmakiola.calendula.domain
+
+import kotlinx.datetime.LocalDateTime
+
+/**
+ * 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 = "",
+)
+
+enum class EventFormProblem {
+    /** No target calendar — none picked and no writable calendar exists. */
+    NoCalendar,
+    EndBeforeStart,
+}
+
+/**
+ * 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).
+ */
+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)
+}

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

@@ -9,6 +9,12 @@ 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,
 )
 
 data class EventInstance(

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

@@ -19,6 +19,7 @@ import de.jeanlucmakiola.calendula.ui.common.CalendarView
 import de.jeanlucmakiola.calendula.ui.common.rememberCalendarSlideSpec
 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.month.MonthScreen
 import de.jeanlucmakiola.calendula.ui.settings.SettingsScreen
 import de.jeanlucmakiola.calendula.ui.week.WeekScreen
@@ -66,6 +67,15 @@ fun CalendarHost(modifier: Modifier = Modifier) {
     var showSettings by rememberSaveable { mutableStateOf(false) }
     val onOpenSettings = { showSettings = true }
 
+    // Event form (v1.2 create) — same held-key pattern as the detail screen:
+    // [heldCreateIso] keeps the prefill date alive through the slide-out.
+    var createDateIso by rememberSaveable { mutableStateOf<String?>(null) }
+    var heldCreateIso by remember { mutableStateOf<String?>(null) }
+    val onCreateEvent: (LocalDate) -> Unit = { date ->
+        heldCreateIso = date.toString()
+        createDateIso = date.toString()
+    }
+
     val slideSpec = rememberCalendarSlideSpec()
 
     Box(modifier = modifier.fillMaxSize()) {
@@ -75,12 +85,14 @@ fun CalendarHost(modifier: Modifier = Modifier) {
                 onSelectView = onSelectView,
                 onEventClick = onEventClick,
                 onOpenSettings = onOpenSettings,
+                onCreateEvent = onCreateEvent,
             )
             CalendarView.Day -> DayScreen(
                 selectedView = view,
                 onSelectView = onSelectView,
                 onEventClick = onEventClick,
                 onOpenSettings = onOpenSettings,
+                onCreateEvent = onCreateEvent,
                 initialDateIso = pendingDayIso,
             )
             CalendarView.Month -> MonthScreen(
@@ -88,6 +100,7 @@ fun CalendarHost(modifier: Modifier = Modifier) {
                 onSelectView = onSelectView,
                 onOpenDay = onOpenDay,
                 onOpenSettings = onOpenSettings,
+                onCreateEvent = onCreateEvent,
             )
         }
 
@@ -108,6 +121,20 @@ fun CalendarHost(modifier: Modifier = Modifier) {
             }
         }
 
+        // 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,
+                    onClose = { createDateIso = null },
+                )
+            }
+        }
+
         // Settings (M4) — full-screen destination, slides over the calendar.
         AnimatedVisibility(
             visible = showSettings,

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

@@ -0,0 +1,55 @@
+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.ExtendedFloatingActionButton
+import androidx.compose.material3.FloatingActionButton
+import androidx.compose.material3.Icon
+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.
+ */
+@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(),
+            exit = scaleOut(),
+        ) {
+            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/day/DayScreen.kt

@@ -1,11 +1,8 @@
 package de.jeanlucmakiola.calendula.ui.day
 
 import androidx.compose.animation.AnimatedContent
-import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.animateColorAsState
 import androidx.compose.animation.core.animateDpAsState
-import androidx.compose.animation.scaleIn
-import androidx.compose.animation.scaleOut
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.gestures.detectHorizontalDragGestures
@@ -28,12 +25,10 @@ import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Menu
-import androidx.compose.material.icons.filled.Refresh
 import androidx.compose.material3.Card
 import androidx.compose.material3.CardDefaults
 import androidx.compose.material3.DrawerValue
 import androidx.compose.material3.ExperimentalMaterial3Api
-import androidx.compose.material3.ExtendedFloatingActionButton
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
@@ -72,6 +67,7 @@ import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import de.jeanlucmakiola.calendula.R
 import de.jeanlucmakiola.calendula.domain.EventInstance
 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.ViewSwitcherPill
@@ -108,6 +104,7 @@ fun DayScreen(
     onSelectView: (CalendarView) -> Unit,
     onEventClick: (EventInstance) -> Unit,
     onOpenSettings: () -> Unit,
+    onCreateEvent: (LocalDate) -> Unit,
     modifier: Modifier = Modifier,
     initialDateIso: String? = null,
     viewModel: DayViewModel = hiltViewModel(),
@@ -172,17 +169,12 @@ fun DayScreen(
                 )
             },
             floatingActionButton = {
-                AnimatedVisibility(
+                CalendarFabColumn(
-                    visible = !isOnToday,
+                    todayVisible = !isOnToday,
-                    enter = scaleIn(),
+                    todayText = stringResource(R.string.day_today_action),
-                    exit = scaleOut(),
+                    onToday = jumpToToday,
-                ) {
+                    onCreate = { onCreateEvent(date) },
-                    ExtendedFloatingActionButton(
+                )
-                        onClick = jumpToToday,
-                        icon = { Icon(Icons.Default.Refresh, contentDescription = null) },
-                        text = { Text(stringResource(R.string.day_today_action)) },
-                    )
-                }
             },
         ) { innerPadding ->
             DayContent(

app/src/main/java/de/jeanlucmakiola/calendula/ui/detail/EventDetailScreen.kt

@@ -1,11 +1,15 @@
 package de.jeanlucmakiola.calendula.ui.detail
 
+import android.Manifest
 import android.content.ActivityNotFoundException
 import android.content.Context
 import android.content.Intent
+import android.content.pm.PackageManager
 import android.icu.text.ListFormatter
 import android.net.Uri
 import androidx.activity.compose.BackHandler
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.isSystemInDarkTheme
@@ -24,6 +28,7 @@ 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.selection.selectable
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
@@ -31,31 +36,40 @@ import androidx.compose.material.icons.automirrored.filled.ArrowBack
 import androidx.compose.material.icons.automirrored.filled.Notes
 import androidx.compose.material.icons.filled.CalendarMonth
 import androidx.compose.material.icons.filled.Delete
-import androidx.compose.material.icons.filled.Edit
 import androidx.compose.material.icons.filled.Notifications
 import androidx.compose.material.icons.filled.People
 import androidx.compose.material.icons.filled.Place
 import androidx.compose.material.icons.filled.Public
 import androidx.compose.material.icons.filled.Repeat
 import androidx.compose.material.icons.filled.Schedule
+import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.RadioButton
 import androidx.compose.material3.Scaffold
+import androidx.compose.material3.SnackbarHost
+import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.Surface
 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.graphics.Color
 import androidx.compose.ui.graphics.vector.ImageVector
 import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.semantics.Role
+import androidx.core.content.ContextCompat
 import androidx.compose.ui.res.pluralStringResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.AnnotatedString
@@ -94,10 +108,10 @@ import kotlin.time.Duration.Companion.seconds
 import kotlin.time.Instant
 
 /**
- * Read-only full-screen event detail (spec S4, realised as a navigation
+ * Full-screen event detail (spec S4, realised as a navigation destination
- * destination rather than a bottom sheet — MD3 list→detail pattern). Back
+ * rather than a bottom sheet — MD3 list→detail pattern). Back gesture and the
- * gesture and the top-bar arrow both return to the calendar. The only action is
+ * top-bar arrow both return to the calendar. Events in writable calendars can
- * tapping the location to open a maps intent.
+ * be deleted from here (v1.1); edit follows in v1.3.
  */
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
@@ -112,10 +126,55 @@ fun EventDetailScreen(
         viewModel.open(eventId, beginMillis, endMillis)
     }
     val state by viewModel.state.collectAsStateWithLifecycle()
+    val deleteState by viewModel.deleteState.collectAsStateWithLifecycle()
 
     BackHandler(onBack = onBack)
 
+    val context = LocalContext.current
+    val snackbarHostState = remember { SnackbarHostState() }
+    var showDeleteDialog by rememberSaveable { mutableStateOf(false) }
+
+    // v1.0 installs only hold READ_CALENDAR; the first write asks for the
+    // upgrade in place. Granting continues straight into the confirm dialog.
+    val writePermissionLauncher = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.RequestPermission(),
+    ) { granted ->
+        if (granted) showDeleteDialog = true
+    }
+    val onDeleteClick = {
+        val granted = ContextCompat.checkSelfPermission(
+            context,
+            Manifest.permission.WRITE_CALENDAR,
+        ) == PackageManager.PERMISSION_GRANTED
+        if (granted) {
+            showDeleteDialog = true
+        } else {
+            writePermissionLauncher.launch(Manifest.permission.WRITE_CALENDAR)
+        }
+    }
+
+    val deleteFailedMessage = stringResource(R.string.event_delete_failed)
+    val writeDeniedMessage = stringResource(R.string.event_delete_write_denied)
+    LaunchedEffect(deleteState) {
+        when (deleteState) {
+            DeleteUiState.Deleted -> {
+                viewModel.consumeDeleteResult()
+                onBack()
+            }
+            DeleteUiState.Failed -> {
+                viewModel.consumeDeleteResult()
+                snackbarHostState.showSnackbar(deleteFailedMessage)
+            }
+            DeleteUiState.NeedsPermission -> {
+                viewModel.consumeDeleteResult()
+                snackbarHostState.showSnackbar(writeDeniedMessage)
+            }
+            DeleteUiState.Idle, DeleteUiState.Deleting -> Unit
+        }
+    }
+
     Scaffold(
+        snackbarHost = { SnackbarHost(snackbarHostState) },
         topBar = {
             TopAppBar(
                 title = {},
@@ -128,17 +187,19 @@ fun EventDetailScreen(
                     }
                 },
                 actions = {
-                    IconButton(onClick = { /* TODO: edit event (V2) */ }) {
+                    // Only writable calendars get actions — WebCal subscriptions,
-                        Icon(
+                    // birthday calendars etc. are read-only at the provider level.
-                            imageVector = Icons.Default.Edit,
+                    val s = state
-                            contentDescription = stringResource(R.string.event_detail_edit),
+                    if (s is EventDetailUiState.Success && s.canModify) {
-                        )
+                        IconButton(
-                    }
+                            onClick = onDeleteClick,
-                    IconButton(onClick = { /* TODO: delete event (V2) */ }) {
+                            enabled = deleteState != DeleteUiState.Deleting,
-                        Icon(
+                        ) {
-                            imageVector = Icons.Default.Delete,
+                            Icon(
-                            contentDescription = stringResource(R.string.event_detail_delete),
+                                imageVector = Icons.Default.Delete,
-                        )
+                                contentDescription = stringResource(R.string.event_detail_delete),
+                            )
+                        }
                     }
                 },
                 colors = TopAppBarDefaults.topAppBarColors(
@@ -159,6 +220,88 @@ fun EventDetailScreen(
             is EventDetailUiState.Success -> EventDetailContent(s, contentModifier)
         }
     }
+
+    val loaded = state
+    if (showDeleteDialog && loaded is EventDetailUiState.Success) {
+        DeleteEventDialog(
+            isRecurring = !loaded.detail.rrule.isNullOrBlank(),
+            onConfirm = { wholeSeries ->
+                showDeleteDialog = false
+                viewModel.delete(wholeSeries)
+            },
+            onDismiss = { showDeleteDialog = false },
+        )
+    }
+}
+
+/**
+ * Delete confirmation. Recurring events choose between cancelling just the
+ * tapped occurrence (default) and removing the whole series.
+ */
+@Composable
+private fun DeleteEventDialog(
+    isRecurring: Boolean,
+    onConfirm: (wholeSeries: Boolean) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    var wholeSeries by rememberSaveable { mutableStateOf(false) }
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = {
+            Text(
+                stringResource(
+                    if (isRecurring) R.string.event_delete_recurring_title
+                    else R.string.event_delete_title,
+                ),
+            )
+        },
+        text = {
+            if (isRecurring) {
+                Column {
+                    DeleteChoiceRow(
+                        selected = !wholeSeries,
+                        label = stringResource(R.string.event_delete_option_occurrence),
+                        onSelect = { wholeSeries = false },
+                    )
+                    DeleteChoiceRow(
+                        selected = wholeSeries,
+                        label = stringResource(R.string.event_delete_option_series),
+                        onSelect = { wholeSeries = true },
+                    )
+                }
+            } else {
+                Text(stringResource(R.string.event_delete_body))
+            }
+        },
+        confirmButton = {
+            TextButton(onClick = { onConfirm(if (isRecurring) wholeSeries else true) }) {
+                Text(
+                    text = stringResource(R.string.event_detail_delete),
+                    color = MaterialTheme.colorScheme.error,
+                )
+            }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) {
+                Text(stringResource(R.string.dialog_cancel))
+            }
+        },
+    )
+}
+
+@Composable
+private fun DeleteChoiceRow(selected: Boolean, label: String, onSelect: () -> Unit) {
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .selectable(selected = selected, role = Role.RadioButton, onClick = onSelect)
+            .padding(vertical = 8.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        RadioButton(selected = selected, onClick = null)
+        Spacer(Modifier.width(8.dp))
+        Text(label, style = MaterialTheme.typography.bodyLarge)
+    }
 }
 
 @Composable

app/src/main/java/de/jeanlucmakiola/calendula/ui/detail/EventDetailUiState.kt

@@ -4,7 +4,7 @@ import de.jeanlucmakiola.calendula.domain.EventDetail
 import de.jeanlucmakiola.calendula.domain.FailureReason
 
 /**
- * UI state for the event-detail bottom sheet (spec S4). Read-only in V1.
+ * UI state for the event-detail screen (spec S4).
  */
 sealed interface EventDetailUiState {
     data object Loading : EventDetailUiState
@@ -13,5 +13,20 @@ sealed interface EventDetailUiState {
         val detail: EventDetail,
         /** Display name of the owning calendar, null if it can't be resolved. */
         val calendarName: String?,
+        /** Whether the owning calendar allows modifying events (shows edit/delete). */
+        val canModify: Boolean = false,
     ) : EventDetailUiState
 }
+
+/**
+ * One-shot state of a delete request, separate from the screen state so a
+ * failed delete leaves the loaded detail visible.
+ */
+sealed interface DeleteUiState {
+    data object Idle : DeleteUiState
+    data object Deleting : DeleteUiState
+    data object Deleted : DeleteUiState
+    /** WRITE_CALENDAR was revoked between the tap and the provider call. */
+    data object NeedsPermission : DeleteUiState
+    data object Failed : DeleteUiState
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/detail/EventDetailViewModel.kt

@@ -12,6 +12,7 @@ import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.flatMapLatest
@@ -19,6 +20,7 @@ import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.flowOf
 import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
 import kotlin.coroutines.cancellation.CancellationException
 import kotlin.time.Instant
 import javax.inject.Inject
@@ -38,6 +40,9 @@ class EventDetailViewModel @Inject constructor(
     // Bumped by retry() to re-run the load for the same target.
     private val _reload = MutableStateFlow(0)
 
+    private val _deleteState = MutableStateFlow<DeleteUiState>(DeleteUiState.Idle)
+    val deleteState: StateFlow<DeleteUiState> = _deleteState.asStateFlow()
+
     val state: StateFlow<EventDetailUiState> =
         combine(_target, _reload) { target, _ -> target }
             .flatMapLatest { target ->
@@ -72,6 +77,38 @@ class EventDetailViewModel @Inject constructor(
         _reload.value += 1
     }
 
+    /**
+     * Delete the open event. [wholeSeries] is meaningful only for recurring
+     * events: false cancels just the tapped occurrence. Result lands in
+     * [deleteState]; the screen consumes it via [consumeDeleteResult].
+     */
+    fun delete(wholeSeries: Boolean) {
+        val target = _target.value ?: return
+        if (_deleteState.value == DeleteUiState.Deleting) return
+        viewModelScope.launch {
+            _deleteState.value = DeleteUiState.Deleting
+            _deleteState.value = try {
+                if (wholeSeries) {
+                    repository.deleteEvent(target.eventId)
+                } else {
+                    repository.deleteOccurrence(target.eventId, target.beginMillis)
+                }
+                DeleteUiState.Deleted
+            } catch (e: CancellationException) {
+                throw e
+            } catch (e: SecurityException) {
+                DeleteUiState.NeedsPermission
+            } catch (e: Exception) {
+                DeleteUiState.Failed
+            }
+        }
+    }
+
+    /** Reset [deleteState] after the screen handled a terminal result. */
+    fun consumeDeleteResult() {
+        _deleteState.value = DeleteUiState.Idle
+    }
+
     private suspend fun loadDetail(target: Target): EventDetailUiState = try {
         val detail = repository.eventDetail(target.eventId)
         // The Events row holds the series start; replace it with this
@@ -82,10 +119,13 @@ class EventDetailViewModel @Inject constructor(
                 end = Instant.fromEpochMilliseconds(target.endMillis),
             ),
         )
-        val calendarName = repository.calendars().first()
+        val calendar = repository.calendars().first()
             .firstOrNull { it.id == corrected.instance.calendarId }
-            ?.displayName
+        EventDetailUiState.Success(
-        EventDetailUiState.Success(corrected, calendarName)
+            detail = corrected,
+            calendarName = calendar?.displayName,
+            canModify = calendar?.canModifyContents == true,
+        )
     } catch (e: CancellationException) {
         throw e
     } catch (e: NoSuchEventException) {

app/src/main/java/de/jeanlucmakiola/calendula/ui/edit/EventEditScreen.kt

@@ -0,0 +1,550 @@
+package de.jeanlucmakiola.calendula.ui.edit
+
+import android.Manifest
+import android.content.pm.PackageManager
+import androidx.activity.compose.BackHandler
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Column
+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.selection.selectable
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.Notes
+import androidx.compose.material.icons.filled.CalendarMonth
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material.icons.filled.Place
+import androidx.compose.material.icons.filled.Schedule
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.Button
+import androidx.compose.material3.DatePicker
+import androidx.compose.material3.DatePickerDialog
+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.OutlinedTextField
+import androidx.compose.material3.RadioButton
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.SnackbarHost
+import androidx.compose.material3.SnackbarHostState
+import androidx.compose.material3.Switch
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.material3.TextField
+import androidx.compose.material3.TextFieldDefaults
+import androidx.compose.material3.TimePicker
+import androidx.compose.material3.TopAppBar
+import androidx.compose.material3.TopAppBarDefaults
+import androidx.compose.material3.rememberDatePickerState
+import androidx.compose.material3.rememberTimePickerState
+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.graphics.Color
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.semantics.Role
+import androidx.compose.ui.unit.dp
+import androidx.core.content.ContextCompat
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventFormProblem
+import de.jeanlucmakiola.calendula.ui.common.currentLocale
+import de.jeanlucmakiola.calendula.ui.common.pastelize
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toJavaLocalDate
+import kotlinx.datetime.toJavaLocalTime
+import kotlinx.datetime.toLocalDateTime
+import java.time.format.DateTimeFormatter
+import java.time.format.FormatStyle
+import java.util.Locale
+import kotlin.time.Clock
+
+/**
+ * Full-screen event form (v1.2: create only). Opens prefilled from the FAB's
+ * anchor date; Save validates, writes via the repository, and closes. The
+ * calendar picker offers only writable calendars.
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun EventEditScreen(
+    initialDateIso: String?,
+    onClose: () -> Unit,
+    viewModel: EventEditViewModel = hiltViewModel(),
+) {
+    LaunchedEffect(initialDateIso) {
+        val date = initialDateIso?.let { runCatching { LocalDate.parse(it) }.getOrNull() }
+            ?: Clock.System.now().toLocalDateTime(TimeZone.currentSystemDefault()).date
+        viewModel.openNew(date)
+    }
+    val state by viewModel.state.collectAsStateWithLifecycle()
+
+    // The form is intentionally forgotten on every close (cancel or save) so
+    // the next FAB tap starts clean; it survives rotation because openNew
+    // no-ops while a form is set.
+    val close = {
+        viewModel.reset()
+        onClose()
+    }
+    BackHandler(onBack = close)
+
+    val context = LocalContext.current
+    val snackbarHostState = remember { SnackbarHostState() }
+
+    // Contextual WRITE_CALENDAR upgrade for v1.0 installs, like delete.
+    val writePermissionLauncher = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.RequestPermission(),
+    ) { granted ->
+        if (granted) viewModel.save()
+    }
+    val onSaveClick = {
+        val granted = ContextCompat.checkSelfPermission(
+            context,
+            Manifest.permission.WRITE_CALENDAR,
+        ) == PackageManager.PERMISSION_GRANTED
+        if (granted) {
+            viewModel.save()
+        } else {
+            writePermissionLauncher.launch(Manifest.permission.WRITE_CALENDAR)
+        }
+    }
+
+    val saveFailedMessage = stringResource(R.string.event_edit_save_failed)
+    val writeDeniedMessage = stringResource(R.string.event_edit_write_denied)
+    LaunchedEffect(state?.saveState) {
+        when (state?.saveState) {
+            SaveUiState.Saved -> close()
+            SaveUiState.Failed -> {
+                viewModel.consumeSaveResult()
+                snackbarHostState.showSnackbar(saveFailedMessage)
+            }
+            SaveUiState.NeedsPermission -> {
+                viewModel.consumeSaveResult()
+                snackbarHostState.showSnackbar(writeDeniedMessage)
+            }
+            SaveUiState.Idle, SaveUiState.Saving, null -> Unit
+        }
+    }
+
+    Scaffold(
+        snackbarHost = { SnackbarHost(snackbarHostState) },
+        topBar = {
+            TopAppBar(
+                title = { Text(stringResource(R.string.event_edit_new_title)) },
+                navigationIcon = {
+                    IconButton(onClick = close) {
+                        Icon(
+                            imageVector = Icons.Default.Close,
+                            contentDescription = stringResource(R.string.event_edit_close),
+                        )
+                    }
+                },
+                actions = {
+                    Button(
+                        onClick = onSaveClick,
+                        enabled = state != null && state?.saveState != SaveUiState.Saving,
+                        modifier = Modifier.padding(end = 12.dp),
+                    ) {
+                        Text(stringResource(R.string.event_edit_save))
+                    }
+                },
+                colors = TopAppBarDefaults.topAppBarColors(
+                    containerColor = MaterialTheme.colorScheme.surface,
+                ),
+            )
+        },
+    ) { innerPadding ->
+        state?.let { s ->
+            EventEditContent(
+                state = s,
+                viewModel = viewModel,
+                modifier = Modifier
+                    .fillMaxSize()
+                    .padding(innerPadding),
+            )
+        }
+    }
+}
+
+private enum class PickerTarget { StartDate, StartTime, EndDate, EndTime }
+
+@Composable
+private fun EventEditContent(
+    state: EventEditUiState,
+    viewModel: EventEditViewModel,
+    modifier: Modifier = Modifier,
+) {
+    val form = state.form
+    val locale = currentLocale()
+    var picker by remember { mutableStateOf<PickerTarget?>(null) }
+    var showCalendarPicker by rememberSaveable { mutableStateOf(false) }
+
+    Column(
+        modifier = modifier
+            .verticalScroll(rememberScrollState())
+            .padding(start = 24.dp, end = 24.dp, top = 8.dp, bottom = 40.dp),
+    ) {
+        // Title: a large borderless field, MD3 "create" idiom.
+        TextField(
+            value = form.title,
+            onValueChange = viewModel::setTitle,
+            placeholder = {
+                Text(
+                    text = stringResource(R.string.event_edit_title_hint),
+                    style = MaterialTheme.typography.headlineSmall,
+                )
+            },
+            textStyle = MaterialTheme.typography.headlineSmall,
+            singleLine = true,
+            colors = TextFieldDefaults.colors(
+                focusedContainerColor = Color.Transparent,
+                unfocusedContainerColor = Color.Transparent,
+            ),
+            modifier = Modifier.fillMaxWidth(),
+        )
+
+        Spacer(Modifier.height(16.dp))
+        HorizontalDivider()
+        Spacer(Modifier.height(16.dp))
+
+        // All-day toggle.
+        Row(
+            verticalAlignment = Alignment.CenterVertically,
+            modifier = Modifier.fillMaxWidth(),
+        ) {
+            Icon(
+                imageVector = Icons.Default.Schedule,
+                contentDescription = null,
+                tint = MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = Modifier.size(24.dp),
+            )
+            Spacer(Modifier.width(16.dp))
+            Text(
+                text = stringResource(R.string.event_detail_all_day),
+                style = MaterialTheme.typography.bodyLarge,
+                modifier = Modifier.weight(1f),
+            )
+            Switch(checked = form.isAllDay, onCheckedChange = viewModel::setAllDay)
+        }
+
+        Spacer(Modifier.height(8.dp))
+
+        // Start / end rows: tappable date + (for timed events) time labels.
+        DateTimeRow(
+            label = stringResource(R.string.event_edit_starts),
+            dateTime = form.start,
+            isAllDay = form.isAllDay,
+            locale = locale,
+            onDateClick = { picker = PickerTarget.StartDate },
+            onTimeClick = { picker = PickerTarget.StartTime },
+        )
+        DateTimeRow(
+            label = stringResource(R.string.event_edit_ends),
+            dateTime = form.end,
+            isAllDay = form.isAllDay,
+            locale = locale,
+            onDateClick = { picker = PickerTarget.EndDate },
+            onTimeClick = { picker = PickerTarget.EndTime },
+            isError = EventFormProblem.EndBeforeStart in state.problems,
+        )
+        if (EventFormProblem.EndBeforeStart in state.problems) {
+            Text(
+                text = stringResource(R.string.event_edit_error_end_before_start),
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.error,
+                modifier = Modifier.padding(start = 40.dp, top = 2.dp),
+            )
+        }
+
+        Spacer(Modifier.height(16.dp))
+        HorizontalDivider()
+        Spacer(Modifier.height(16.dp))
+
+        // Calendar picker row.
+        val selectedCalendar = state.calendars.firstOrNull { it.id == form.calendarId }
+        val dark = isSystemInDarkTheme()
+        Row(
+            verticalAlignment = Alignment.CenterVertically,
+            modifier = Modifier
+                .fillMaxWidth()
+                .clickable(enabled = state.calendars.isNotEmpty()) { showCalendarPicker = true }
+                .padding(vertical = 8.dp),
+        ) {
+            Icon(
+                imageVector = Icons.Default.CalendarMonth,
+                contentDescription = stringResource(R.string.event_detail_calendar),
+                tint = selectedCalendar?.let { pastelize(it.color, dark) }
+                    ?: MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = Modifier.size(24.dp),
+            )
+            Spacer(Modifier.width(16.dp))
+            Column(modifier = Modifier.weight(1f)) {
+                Text(
+                    text = selectedCalendar?.displayName
+                        ?: stringResource(R.string.event_edit_error_no_calendar),
+                    style = MaterialTheme.typography.bodyLarge,
+                    color = if (selectedCalendar == null) {
+                        MaterialTheme.colorScheme.error
+                    } else {
+                        Color.Unspecified
+                    },
+                )
+                selectedCalendar?.accountName?.takeIf { it.isNotBlank() }?.let { account ->
+                    Text(
+                        text = account,
+                        style = MaterialTheme.typography.bodySmall,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    )
+                }
+            }
+        }
+
+        Spacer(Modifier.height(16.dp))
+        HorizontalDivider()
+        Spacer(Modifier.height(16.dp))
+
+        OutlinedTextField(
+            value = form.location,
+            onValueChange = viewModel::setLocation,
+            label = { Text(stringResource(R.string.event_detail_location)) },
+            leadingIcon = { Icon(Icons.Default.Place, contentDescription = null) },
+            singleLine = true,
+            modifier = Modifier.fillMaxWidth(),
+        )
+        Spacer(Modifier.height(12.dp))
+        OutlinedTextField(
+            value = form.description,
+            onValueChange = viewModel::setDescription,
+            label = { Text(stringResource(R.string.event_detail_description)) },
+            leadingIcon = { Icon(Icons.AutoMirrored.Filled.Notes, contentDescription = null) },
+            minLines = 3,
+            modifier = Modifier.fillMaxWidth(),
+        )
+    }
+
+    when (picker) {
+        PickerTarget.StartDate -> DatePickerAlert(
+            initial = form.start.date,
+            onConfirm = { viewModel.setStartDate(it); picker = null },
+            onDismiss = { picker = null },
+        )
+        PickerTarget.EndDate -> DatePickerAlert(
+            initial = form.end.date,
+            onConfirm = { viewModel.setEndDate(it); picker = null },
+            onDismiss = { picker = null },
+        )
+        PickerTarget.StartTime -> TimePickerAlert(
+            initial = form.start.time,
+            onConfirm = { viewModel.setStartTime(it); picker = null },
+            onDismiss = { picker = null },
+        )
+        PickerTarget.EndTime -> TimePickerAlert(
+            initial = form.end.time,
+            onConfirm = { viewModel.setEndTime(it); picker = null },
+            onDismiss = { picker = null },
+        )
+        null -> Unit
+    }
+
+    if (showCalendarPicker) {
+        CalendarPickerDialog(
+            calendars = state.calendars,
+            selectedId = form.calendarId,
+            onSelect = {
+                viewModel.setCalendar(it)
+                showCalendarPicker = false
+            },
+            onDismiss = { showCalendarPicker = false },
+        )
+    }
+}
+
+/** One schedule row: label, then tappable date and (unless all-day) time. */
+@Composable
+private fun DateTimeRow(
+    label: String,
+    dateTime: LocalDateTime,
+    isAllDay: Boolean,
+    locale: Locale,
+    onDateClick: () -> Unit,
+    onTimeClick: () -> Unit,
+    isError: Boolean = false,
+) {
+    val dateFormat = remember(locale) {
+        DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM).withLocale(locale)
+    }
+    val timeFormat = remember(locale) {
+        DateTimeFormatter.ofLocalizedTime(FormatStyle.SHORT).withLocale(locale)
+    }
+    val contentColor = if (isError) {
+        MaterialTheme.colorScheme.error
+    } else {
+        MaterialTheme.colorScheme.onSurface
+    }
+    Row(
+        verticalAlignment = Alignment.CenterVertically,
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(start = 40.dp, top = 8.dp, bottom = 8.dp),
+    ) {
+        Text(
+            text = label,
+            style = MaterialTheme.typography.bodyLarge,
+            modifier = Modifier.weight(1f),
+        )
+        Text(
+            text = dateFormat.format(dateTime.date.toJavaLocalDate()),
+            style = MaterialTheme.typography.bodyLarge,
+            color = contentColor,
+            modifier = Modifier
+                .clickable(onClick = onDateClick)
+                .padding(8.dp),
+        )
+        if (!isAllDay) {
+            Text(
+                text = timeFormat.format(dateTime.time.toJavaLocalTime()),
+                style = MaterialTheme.typography.bodyLarge,
+                color = contentColor,
+                modifier = Modifier
+                    .clickable(onClick = onTimeClick)
+                    .padding(8.dp),
+            )
+        }
+    }
+}
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+private fun DatePickerAlert(
+    initial: LocalDate,
+    onConfirm: (LocalDate) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    // DatePicker speaks UTC-midnight millis; epoch-day arithmetic keeps the
+    // conversion zone-proof in both directions.
+    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)
+    }
+}
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+private fun TimePickerAlert(
+    initial: LocalTime,
+    onConfirm: (LocalTime) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    val state = rememberTimePickerState(
+        initialHour = initial.hour,
+        initialMinute = initial.minute,
+    )
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        confirmButton = {
+            TextButton(onClick = { onConfirm(LocalTime(state.hour, state.minute)) }) {
+                Text(stringResource(R.string.dialog_ok))
+            }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) { Text(stringResource(R.string.dialog_cancel)) }
+        },
+        text = { TimePicker(state = state) },
+    )
+}
+
+@Composable
+private fun CalendarPickerDialog(
+    calendars: List<CalendarSource>,
+    selectedId: Long?,
+    onSelect: (Long) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    val dark = isSystemInDarkTheme()
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = { Text(stringResource(R.string.event_detail_calendar)) },
+        text = {
+            Column {
+                calendars.forEach { calendar ->
+                    Row(
+                        verticalAlignment = Alignment.CenterVertically,
+                        modifier = Modifier
+                            .fillMaxWidth()
+                            .selectable(
+                                selected = calendar.id == selectedId,
+                                role = Role.RadioButton,
+                                onClick = { onSelect(calendar.id) },
+                            )
+                            .padding(vertical = 8.dp),
+                    ) {
+                        RadioButton(selected = calendar.id == selectedId, onClick = null)
+                        Spacer(Modifier.width(8.dp))
+                        Icon(
+                            imageVector = Icons.Default.CalendarMonth,
+                            contentDescription = null,
+                            tint = pastelize(calendar.color, dark),
+                            modifier = Modifier.size(20.dp),
+                        )
+                        Spacer(Modifier.width(8.dp))
+                        Column {
+                            Text(calendar.displayName, style = MaterialTheme.typography.bodyLarge)
+                            if (calendar.accountName.isNotBlank()) {
+                                Text(
+                                    text = calendar.accountName,
+                                    style = MaterialTheme.typography.bodySmall,
+                                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                                )
+                            }
+                        }
+                    }
+                }
+            }
+        },
+        confirmButton = {
+            TextButton(onClick = onDismiss) { Text(stringResource(R.string.dialog_cancel)) }
+        },
+    )
+}
+
+private const val MILLIS_PER_DAY = 86_400_000L

app/src/main/java/de/jeanlucmakiola/calendula/ui/edit/EventEditUiState.kt

@@ -0,0 +1,29 @@
+package de.jeanlucmakiola.calendula.ui.edit
+
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventForm
+import de.jeanlucmakiola.calendula.domain.EventFormProblem
+
+/**
+ * UI state for the event form (v1.2: create; v1.3 reuses it for edit). Null
+ * form means the screen hasn't been opened yet.
+ */
+data class EventEditUiState(
+    /** The form with its calendar id resolved (picked > last used > first writable). */
+    val form: EventForm,
+    /** Calendars that accept writes — the only valid targets. */
+    val calendars: List<CalendarSource>,
+    /** Validation problems; empty until a save was attempted. */
+    val problems: Set<EventFormProblem>,
+    val saveState: SaveUiState,
+)
+
+/** One-shot state of a save request, mirroring DeleteUiState on the detail screen. */
+sealed interface SaveUiState {
+    data object Idle : SaveUiState
+    data object Saving : SaveUiState
+    data object Saved : SaveUiState
+    /** WRITE_CALENDAR was revoked between the tap and the provider call. */
+    data object NeedsPermission : SaveUiState
+    data object Failed : SaveUiState
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/edit/EventEditViewModel.kt

@@ -0,0 +1,160 @@
+package de.jeanlucmakiola.calendula.ui.edit
+
+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.CalendarPrefs
+import de.jeanlucmakiola.calendula.domain.EventForm
+import de.jeanlucmakiola.calendula.domain.problems
+import kotlinx.coroutines.CoroutineDispatcher
+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.flowOn
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toInstant
+import kotlinx.datetime.toLocalDateTime
+import kotlin.coroutines.cancellation.CancellationException
+import kotlin.time.Clock
+import kotlin.time.Duration.Companion.hours
+import kotlin.time.Instant
+import javax.inject.Inject
+
+/**
+ * Holds the event form being composed. The form's calendar id resolves to
+ * (user pick > last used > first writable); the resolved value is what the UI
+ * shows and what gets saved.
+ */
+@HiltViewModel
+class EventEditViewModel @Inject constructor(
+    private val repository: CalendarRepository,
+    private val prefs: CalendarPrefs,
+    @IoDispatcher private val io: CoroutineDispatcher,
+) : ViewModel() {
+
+    private val _form = MutableStateFlow<EventForm?>(null)
+    private val _saveState = MutableStateFlow<SaveUiState>(SaveUiState.Idle)
+    // Problems stay hidden until the first save attempt, so a half-filled
+    // form isn't already shouting errors.
+    private val _showProblems = MutableStateFlow(false)
+
+    val state: StateFlow<EventEditUiState?> = combine(
+        _form,
+        repository.calendars()
+            .map { calendars -> calendars.filter { it.canModifyContents } }
+            .catch { emit(emptyList()) },
+        prefs.lastUsedCalendarId,
+        _saveState,
+        _showProblems,
+    ) { form, writable, lastUsed, saveState, showProblems ->
+        if (form == null) return@combine null
+        val resolvedId = form.calendarId
+            ?: lastUsed?.takeIf { id -> writable.any { it.id == id } }
+            ?: writable.firstOrNull()?.id
+        val resolved = form.copy(calendarId = resolvedId)
+        EventEditUiState(
+            form = resolved,
+            calendars = writable,
+            problems = if (showProblems) resolved.problems() else emptySet(),
+            saveState = saveState,
+        )
+    }
+        .flowOn(io)
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5_000L),
+            initialValue = null,
+        )
+
+    /**
+     * Initialise a fresh form for a new event on [date]. No-op when a form is
+     * already open, so user input survives configuration changes; [reset]
+     * clears it when the screen closes.
+     */
+    fun openNew(date: LocalDate) {
+        if (_form.value != null) return
+        val zone = TimeZone.currentSystemDefault()
+        val now = Clock.System.now()
+        val start = if (date == now.toLocalDateTime(zone).date) {
+            // Today: the next full hour (may roll into tomorrow before midnight).
+            val hourMillis = 3_600_000L
+            val rounded = (now.toEpochMilliseconds() / hourMillis + 1) * hourMillis
+            Instant.fromEpochMilliseconds(rounded).toLocalDateTime(zone)
+        } else {
+            LocalDateTime(date, LocalTime(9, 0))
+        }
+        val end = (start.toInstant(zone) + 1.hours).toLocalDateTime(zone)
+        _form.value = EventForm(calendarId = null, start = start, end = end)
+    }
+
+    /** Forget the open form; the next [openNew] starts clean. */
+    fun reset() {
+        _form.value = null
+        _saveState.value = SaveUiState.Idle
+        _showProblems.value = false
+    }
+
+    fun setTitle(value: String) = update { it.copy(title = value) }
+    fun setLocation(value: String) = update { it.copy(location = value) }
+    fun setDescription(value: String) = update { it.copy(description = value) }
+    fun setAllDay(value: Boolean) = update { it.copy(isAllDay = value) }
+    fun setCalendar(id: Long) = update { it.copy(calendarId = id) }
+
+    /** Moving the start drags the end along, preserving the duration. */
+    fun setStartDate(date: LocalDate) = moveStart { LocalDateTime(date, it.time) }
+    fun setStartTime(time: LocalTime) = moveStart { LocalDateTime(it.date, time) }
+    fun setEndDate(date: LocalDate) = update { it.copy(end = LocalDateTime(date, it.end.time)) }
+    fun setEndTime(time: LocalTime) = update { it.copy(end = LocalDateTime(it.end.date, time)) }
+
+    /** Validate and write. Terminal results land in [saveState]. */
+    fun save() {
+        val current = state.value ?: return
+        if (current.saveState == SaveUiState.Saving) return
+        val form = current.form
+        if (form.problems().isNotEmpty()) {
+            _showProblems.value = true
+            return
+        }
+        viewModelScope.launch {
+            _saveState.value = SaveUiState.Saving
+            _saveState.value = try {
+                repository.createEvent(form)
+                prefs.setLastUsedCalendarId(requireNotNull(form.calendarId))
+                SaveUiState.Saved
+            } catch (e: CancellationException) {
+                throw e
+            } catch (e: SecurityException) {
+                SaveUiState.NeedsPermission
+            } catch (e: Exception) {
+                SaveUiState.Failed
+            }
+        }
+    }
+
+    /** Reset [saveState] after the screen handled a terminal result. */
+    fun consumeSaveResult() {
+        _saveState.value = SaveUiState.Idle
+    }
+
+    private fun moveStart(transform: (LocalDateTime) -> LocalDateTime) = update { form ->
+        val zone = TimeZone.currentSystemDefault()
+        val newStart = transform(form.start)
+        val duration = form.end.toInstant(zone) - form.start.toInstant(zone)
+        val newEnd = (newStart.toInstant(zone) + duration).toLocalDateTime(zone)
+        form.copy(start = newStart, end = newEnd)
+    }
+
+    private inline fun update(block: (EventForm) -> EventForm) {
+        _form.value = _form.value?.let(block)
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/month/MonthScreen.kt

@@ -1,10 +1,7 @@
 package de.jeanlucmakiola.calendula.ui.month
 
 import androidx.compose.animation.AnimatedContent
-import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.core.animateFloatAsState
-import androidx.compose.animation.scaleIn
-import androidx.compose.animation.scaleOut
 import androidx.compose.foundation.background
 import androidx.compose.foundation.gestures.detectHorizontalDragGestures
 import androidx.compose.foundation.interaction.MutableInteractionSource
@@ -23,13 +20,11 @@ import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Menu
-import androidx.compose.material.icons.filled.Refresh
 import androidx.compose.material3.Card
 import androidx.compose.material3.CardDefaults
 import androidx.compose.material3.DrawerValue
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
-import androidx.compose.material3.ExtendedFloatingActionButton
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
@@ -62,6 +57,7 @@ import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import de.jeanlucmakiola.calendula.R
 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.ViewSwitcherPill
@@ -74,8 +70,11 @@ import kotlinx.coroutines.launch
 import kotlinx.datetime.DateTimeUnit
 import kotlinx.datetime.DayOfWeek
 import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
 import kotlinx.datetime.YearMonth
 import kotlinx.datetime.plus
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Clock
 import java.time.format.TextStyle as JavaTextStyle
 import java.util.Locale
 
@@ -86,6 +85,7 @@ fun MonthScreen(
     onSelectView: (CalendarView) -> Unit,
     onOpenDay: (LocalDate) -> Unit,
     onOpenSettings: () -> Unit,
+    onCreateEvent: (LocalDate) -> Unit,
     modifier: Modifier = Modifier,
     viewModel: MonthViewModel = hiltViewModel(),
 ) {
@@ -147,17 +147,20 @@ fun MonthScreen(
                 )
             },
             floatingActionButton = {
-                AnimatedVisibility(
+                CalendarFabColumn(
-                    visible = !isOnCurrentMonth,
+                    todayVisible = !isOnCurrentMonth,
-                    enter = scaleIn(),
+                    todayText = stringResource(R.string.month_today_action),
-                    exit = scaleOut(),
+                    onToday = jumpToToday,
-                ) {
+                    onCreate = {
-                    ExtendedFloatingActionButton(
+                        // Anchor on today when its month is shown, else the 1st.
-                        onClick = jumpToToday,
+                        val today = Clock.System.now()
-                        icon = { Icon(Icons.Default.Refresh, contentDescription = null) },
+                            .toLocalDateTime(TimeZone.currentSystemDefault()).date
-                        text = { Text(stringResource(R.string.month_today_action)) },
+                        onCreateEvent(
-                    )
+                            if (isOnCurrentMonth) today
-                }
+                            else LocalDate(month.year, month.month, 1),
+                        )
+                    },
+                )
             },
         ) { innerPadding ->
             Column(

app/src/main/java/de/jeanlucmakiola/calendula/ui/permission/PermissionScreen.kt

@@ -56,6 +56,11 @@ import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.compose.foundation.Image
 import de.jeanlucmakiola.calendula.R
 
+private val CALENDAR_PERMISSIONS = arrayOf(
+    Manifest.permission.READ_CALENDAR,
+    Manifest.permission.WRITE_CALENDAR,
+)
+
 // MD3 8dp spacing scale, scoped to this screen.
 private object Space {
     val xs = 8.dp
@@ -73,10 +78,17 @@ fun PermissionScreen(
 ) {
     val state by viewModel.state.collectAsStateWithLifecycle()
 
+    // READ and WRITE are requested together (one system dialog — same
+    // permission group), but only READ gates the app: declining write keeps
+    // Calendula usable read-only.
     val launcher = rememberLauncherForActivityResult(
-        contract = ActivityResultContracts.RequestPermission(),
+        contract = ActivityResultContracts.RequestMultiplePermissions(),
-    ) { granted ->
+    ) { results ->
-        if (granted) viewModel.onGranted() else viewModel.onDenied()
+        if (results[Manifest.permission.READ_CALENDAR] == true) {
+            viewModel.onGranted()
+        } else {
+            viewModel.onDenied()
+        }
     }
 
     LaunchedEffect(state) {
@@ -85,13 +97,13 @@ fun PermissionScreen(
 
     when (state) {
         is PermissionUiState.Rationale -> RationaleContent(
-            onRequest = { launcher.launch(Manifest.permission.READ_CALENDAR) },
+            onRequest = { launcher.launch(CALENDAR_PERMISSIONS) },
             modifier = modifier,
         )
         is PermissionUiState.Denied -> DeniedContent(
             onRetry = {
                 viewModel.onRetry()
-                launcher.launch(Manifest.permission.READ_CALENDAR)
+                launcher.launch(CALENDAR_PERMISSIONS)
             },
             modifier = modifier,
         )

app/src/main/java/de/jeanlucmakiola/calendula/ui/week/WeekScreen.kt

@@ -1,11 +1,8 @@
 package de.jeanlucmakiola.calendula.ui.week
 
 import androidx.compose.animation.AnimatedContent
-import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.animateColorAsState
 import androidx.compose.animation.core.animateDpAsState
-import androidx.compose.animation.scaleIn
-import androidx.compose.animation.scaleOut
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.gestures.detectHorizontalDragGestures
@@ -31,12 +28,10 @@ import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Menu
-import androidx.compose.material.icons.filled.Refresh
 import androidx.compose.material3.Card
 import androidx.compose.material3.CardDefaults
 import androidx.compose.material3.DrawerValue
 import androidx.compose.material3.ExperimentalMaterial3Api
-import androidx.compose.material3.ExtendedFloatingActionButton
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
@@ -77,6 +72,7 @@ import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import de.jeanlucmakiola.calendula.R
 import de.jeanlucmakiola.calendula.domain.EventInstance
 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.ViewSwitcherPill
@@ -88,7 +84,10 @@ import de.jeanlucmakiola.calendula.ui.common.pastelize
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.launch
 import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
 import kotlinx.datetime.plus
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Clock
 import java.time.format.TextStyle as JavaTextStyle
 import java.util.Locale
 import kotlin.math.roundToInt
@@ -113,6 +112,7 @@ fun WeekScreen(
     onSelectView: (CalendarView) -> Unit,
     onEventClick: (EventInstance) -> Unit,
     onOpenSettings: () -> Unit,
+    onCreateEvent: (LocalDate) -> Unit,
     modifier: Modifier = Modifier,
     viewModel: WeekViewModel = hiltViewModel(),
 ) {
@@ -174,17 +174,17 @@ fun WeekScreen(
                 )
             },
             floatingActionButton = {
-                AnimatedVisibility(
+                CalendarFabColumn(
-                    visible = !isOnCurrentWeek,
+                    todayVisible = !isOnCurrentWeek,
-                    enter = scaleIn(),
+                    todayText = stringResource(R.string.week_today_action),
-                    exit = scaleOut(),
+                    onToday = jumpToToday,
-                ) {
+                    onCreate = {
-                    ExtendedFloatingActionButton(
+                        // Anchor on today when it's in view, else the week's first day.
-                        onClick = jumpToToday,
+                        val today = Clock.System.now()
-                        icon = { Icon(Icons.Default.Refresh, contentDescription = null) },
+                            .toLocalDateTime(TimeZone.currentSystemDefault()).date
-                        text = { Text(stringResource(R.string.week_today_action)) },
+                        onCreateEvent(if (isOnCurrentWeek) today else weekStart)
-                    )
+                    },
-                }
+                )
             },
         ) { innerPadding ->
             WeekContent(

app/src/main/res/values-de/strings.xml

@@ -13,7 +13,7 @@
 
     <!-- Permission-Flow (F1) -->
     <string name="permission_rationale_title">Alle Termine, schön im Blick</string>
-    <string name="permission_rationale_body">Calendula braucht Lesezugriff auf deinen Kalender, um deine Termine zu zeigen. Mehr verlangt die App nie.</string>
+    <string name="permission_rationale_body">Calendula braucht Zugriff auf deinen Kalender, um deine Termine zu zeigen und zu verwalten. Mehr verlangt die App nie.</string>
     <string name="permission_request_button">Kalender-Zugriff erlauben</string>
     <string name="permission_denied_title">Kalender-Zugriff abgelehnt</string>
     <string name="permission_denied_body">Ohne Kalender-Zugriff kann Calendula keine Termine anzeigen. Du kannst den Zugriff in den System-Einstellungen wieder erlauben.</string>
@@ -25,7 +25,7 @@
     <string name="permission_benefit_sync_body">Google, CalDAV, lokal — alles, was synchronisiert ist, erscheint automatisch.</string>
     <string name="permission_benefit_privacy_title">Kein Tracking, niemals</string>
     <string name="permission_benefit_privacy_body">Keine Telemetrie, keine Analyse, keine Werbung.</string>
-    <string name="permission_privacy_footnote">Nur Lesezugriff · keine Internet-Berechtigung</string>
+    <string name="permission_privacy_footnote">Bleibt auf deinem Gerät · keine Internet-Berechtigung</string>
 
     <!-- Monatsansicht (S1) -->
     <string name="month_prev">Vorheriger Monat</string>
@@ -45,8 +45,28 @@
 
     <!-- Event-Detail-Screen (S4) -->
     <string name="event_detail_back">Zurück</string>
-    <string name="event_detail_edit">Bearbeiten</string>
     <string name="event_detail_delete">Löschen</string>
+    <string name="event_delete_title">Termin löschen?</string>
+    <string name="event_delete_body">Der Termin wird aus deinem Kalender und von allen synchronisierten Geräten entfernt.</string>
+    <string name="event_delete_recurring_title">Wiederkehrenden Termin löschen</string>
+    <string name="event_delete_option_occurrence">Nur dieser Termin</string>
+    <string name="event_delete_option_series">Alle Termine der Serie</string>
+    <string name="event_delete_failed">Termin konnte nicht gelöscht werden</string>
+    <string name="event_delete_write_denied">Calendula braucht Schreibzugriff, um Termine zu löschen</string>
+    <string name="dialog_cancel">Abbrechen</string>
+    <string name="dialog_ok">OK</string>
+
+    <!-- Termin-Formular (v1.2 Erstellen) -->
+    <string name="event_edit_new_title">Neuer Termin</string>
+    <string name="event_edit_close">Schließen</string>
+    <string name="event_edit_save">Speichern</string>
+    <string name="event_edit_title_hint">Titel hinzufügen</string>
+    <string name="event_edit_starts">Beginn</string>
+    <string name="event_edit_ends">Ende</string>
+    <string name="event_edit_error_end_before_start">Endet vor dem Beginn</string>
+    <string name="event_edit_error_no_calendar">Kein beschreibbarer Kalender verfügbar</string>
+    <string name="event_edit_save_failed">Termin konnte nicht gespeichert werden</string>
+    <string name="event_edit_write_denied">Calendula braucht Schreibzugriff, um Termine zu erstellen</string>
     <string name="event_detail_all_day">Ganztägig</string>
     <string name="event_detail_calendar">Kalender</string>
     <string name="event_detail_calendar_unknown">Unbekannter Kalender</string>

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

@@ -14,7 +14,7 @@
 
     <!-- Permission flow (F1) -->
     <string name="permission_rationale_title">See all your events, beautifully</string>
-    <string name="permission_rationale_body">Calendula needs to read your calendar to show your events. That\'s the only thing it ever asks for.</string>
+    <string name="permission_rationale_body">Calendula needs access to your calendar to show and manage your events. That\'s the only thing it ever asks for.</string>
     <string name="permission_request_button">Grant calendar access</string>
     <string name="permission_denied_title">Calendar access denied</string>
     <string name="permission_denied_body">Calendula cannot show events without calendar access. You can grant it again in the system settings.</string>
@@ -26,7 +26,7 @@
     <string name="permission_benefit_sync_body">Google, CalDAV, local — anything synced to the device just appears.</string>
     <string name="permission_benefit_privacy_title">No tracking, ever</string>
     <string name="permission_benefit_privacy_body">Zero telemetry, zero analytics, no ads.</string>
-    <string name="permission_privacy_footnote">Read-only · no internet permission</string>
+    <string name="permission_privacy_footnote">Stays on your device · no internet permission</string>
 
     <!-- Month view (S1) -->
     <string name="month_prev">Previous month</string>
@@ -46,8 +46,28 @@
 
     <!-- Event detail screen (S4) -->
     <string name="event_detail_back">Back</string>
-    <string name="event_detail_edit">Edit</string>
     <string name="event_detail_delete">Delete</string>
+    <string name="event_delete_title">Delete event?</string>
+    <string name="event_delete_body">The event is removed from your calendar and from every device it syncs to.</string>
+    <string name="event_delete_recurring_title">Delete recurring event</string>
+    <string name="event_delete_option_occurrence">Only this event</string>
+    <string name="event_delete_option_series">All events in the series</string>
+    <string name="event_delete_failed">Couldn\'t delete the event</string>
+    <string name="event_delete_write_denied">Calendula needs write access to delete events</string>
+    <string name="dialog_cancel">Cancel</string>
+    <string name="dialog_ok">OK</string>
+
+    <!-- Event form (v1.2 create) -->
+    <string name="event_edit_new_title">New event</string>
+    <string name="event_edit_close">Close</string>
+    <string name="event_edit_save">Save</string>
+    <string name="event_edit_title_hint">Add title</string>
+    <string name="event_edit_starts">Starts</string>
+    <string name="event_edit_ends">Ends</string>
+    <string name="event_edit_error_end_before_start">Ends before it starts</string>
+    <string name="event_edit_error_no_calendar">No writable calendar available</string>
+    <string name="event_edit_save_failed">Couldn\'t save the event</string>
+    <string name="event_edit_write_denied">Calendula needs write access to create events</string>
     <string name="event_detail_all_day">All day</string>
     <string name="event_detail_calendar">Calendar</string>
     <string name="event_detail_calendar_unknown">Unknown calendar</string>

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/CalendarMapperTest.kt

@@ -1,5 +1,6 @@
 package de.jeanlucmakiola.calendula.data.calendar
 
+import android.provider.CalendarContract
 import com.google.common.truth.Truth.assertThat
 import org.junit.jupiter.api.Test
 
@@ -12,6 +13,7 @@ class CalendarMapperTest {
         accountType: String? = "LOCAL",
         color: Int = 0,
         visible: Int = 1,
+        accessLevel: Int = CalendarContract.Calendars.CAL_ACCESS_OWNER,
     ): MapColumnReader = MapColumnReader(
         CalendarProjection.IDX_ID to id,
         CalendarProjection.IDX_DISPLAY_NAME to displayName,
@@ -19,6 +21,7 @@ class CalendarMapperTest {
         CalendarProjection.IDX_ACCOUNT_TYPE to accountType,
         CalendarProjection.IDX_COLOR to color,
         CalendarProjection.IDX_VISIBLE to visible,
+        CalendarProjection.IDX_ACCESS_LEVEL to accessLevel,
     )
 
     @Test
@@ -39,6 +42,7 @@ class CalendarMapperTest {
                 accountType = "com.google",
                 color = 0xFF112233.toInt(),
                 isVisibleInSystem = true,
+                canModifyContents = true,
             )
         )
     }
@@ -65,4 +69,25 @@ class CalendarMapperTest {
         assertThat(src.accountName).isEqualTo("")
         assertThat(src.accountType).isEqualTo("")
     }
+
+    @Test
+    fun `contributor access and above can modify contents`() {
+        val contributor = reader(accessLevel = CalendarContract.Calendars.CAL_ACCESS_CONTRIBUTOR)
+        val owner = reader(accessLevel = CalendarContract.Calendars.CAL_ACCESS_OWNER)
+        assertThat(contributor.toCalendarSource().canModifyContents).isTrue()
+        assertThat(owner.toCalendarSource().canModifyContents).isTrue()
+    }
+
+    @Test
+    fun `read access cannot modify contents`() {
+        val src = reader(accessLevel = CalendarContract.Calendars.CAL_ACCESS_READ)
+        assertThat(src.toCalendarSource().canModifyContents).isFalse()
+    }
+
+    @Test
+    fun `missing access level defaults to read-only`() {
+        // WebCal subscriptions on some providers report level 0 (CAL_ACCESS_NONE).
+        val src = reader(accessLevel = CalendarContract.Calendars.CAL_ACCESS_NONE)
+        assertThat(src.toCalendarSource().canModifyContents).isFalse()
+    }
 }

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/CalendarRepositoryImplTest.kt

@@ -7,8 +7,12 @@ import app.cash.turbine.test
 import com.google.common.truth.Truth.assertThat
 import de.jeanlucmakiola.calendula.data.prefs.CalendarPrefs
 import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventForm
 import de.jeanlucmakiola.calendula.domain.EventInstance
 import kotlinx.coroutines.Dispatchers
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.runTest
@@ -157,6 +161,80 @@ class CalendarRepositoryImplTest {
         }
     }
 
+    @Test
+    fun `createEvent delegates and returns the new id`(@TempDir tempDir: Path) = runTest {
+        val fake = FakeCalendarDataSource().apply { nextInsertId = 77L }
+        val repo = CalendarRepositoryImpl(fake, newPrefs(tempDir), Dispatchers.Unconfined)
+        val form = EventForm(
+            calendarId = 1L,
+            title = "Stand-up",
+            start = LocalDateTime(LocalDate(2026, 6, 12), LocalTime(9, 0)),
+            end = LocalDateTime(LocalDate(2026, 6, 12), LocalTime(9, 15)),
+        )
+
+        val id = repo.createEvent(form)
+
+        assertThat(id).isEqualTo(77L)
+        assertThat(fake.insertedForms).containsExactly(form)
+    }
+
+    @Test
+    fun `createEvent propagates write failures`(@TempDir tempDir: Path) = runTest {
+        val fake = FakeCalendarDataSource().apply {
+            writeError = WriteFailedException("insert event")
+        }
+        val repo = CalendarRepositoryImpl(fake, newPrefs(tempDir), Dispatchers.Unconfined)
+        val form = EventForm(
+            calendarId = 1L,
+            start = LocalDateTime(LocalDate(2026, 6, 12), LocalTime(9, 0)),
+            end = LocalDateTime(LocalDate(2026, 6, 12), LocalTime(10, 0)),
+        )
+
+        try {
+            repo.createEvent(form)
+            error("Expected WriteFailedException")
+        } catch (expected: WriteFailedException) {
+            assertThat(expected.message).contains("insert")
+        }
+    }
+
+    @Test
+    fun `deleteEvent delegates to the data source`(@TempDir tempDir: Path) = runTest {
+        val fake = FakeCalendarDataSource()
+        val repo = CalendarRepositoryImpl(fake, newPrefs(tempDir), Dispatchers.Unconfined)
+
+        repo.deleteEvent(eventId = 42L)
+
+        assertThat(fake.deletedEventIds).containsExactly(42L)
+        assertThat(fake.deletedOccurrences).isEmpty()
+    }
+
+    @Test
+    fun `deleteOccurrence forwards event id and begin time`(@TempDir tempDir: Path) = runTest {
+        val fake = FakeCalendarDataSource()
+        val repo = CalendarRepositoryImpl(fake, newPrefs(tempDir), Dispatchers.Unconfined)
+
+        repo.deleteOccurrence(eventId = 42L, beginMillis = 1_000L)
+
+        assertThat(fake.deletedOccurrences).containsExactly(42L to 1_000L)
+        assertThat(fake.deletedEventIds).isEmpty()
+    }
+
+    @Test
+    fun `deleteEvent propagates write failures`(@TempDir tempDir: Path) = runTest {
+        val fake = FakeCalendarDataSource().apply {
+            writeError = WriteFailedException("delete event id=42")
+        }
+        val repo = CalendarRepositoryImpl(fake, newPrefs(tempDir), Dispatchers.Unconfined)
+
+        try {
+            repo.deleteEvent(eventId = 42L)
+            error("Expected WriteFailedException")
+        } catch (expected: WriteFailedException) {
+            assertThat(expected.message).contains("42")
+        }
+    }
+
     @Test
     fun `eventDetail throws NoSuchEventException when data source returns null`(@TempDir tempDir: Path) = runTest {
         val fake = FakeCalendarDataSource().apply {

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/EventWriteMapperTest.kt

@@ -0,0 +1,49 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import com.google.common.truth.Truth.assertThat
+import de.jeanlucmakiola.calendula.domain.EventForm
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
+import org.junit.jupiter.api.Test
+import java.time.ZoneId
+
+class EventWriteMapperTest {
+
+    private val berlin: ZoneId = ZoneId.of("Europe/Berlin")
+
+    private fun form(
+        isAllDay: Boolean = false,
+        start: LocalDateTime = LocalDateTime(LocalDate(2026, 6, 11), LocalTime(10, 0)),
+        end: LocalDateTime = LocalDateTime(LocalDate(2026, 6, 11), LocalTime(11, 30)),
+    ): EventForm = EventForm(calendarId = 1L, isAllDay = isAllDay, start = start, end = end)
+
+    @Test
+    fun `timed event resolves wall clock in the given zone`() {
+        val times = form().toWriteTimes(berlin)
+        // 2026-06-11 is CEST (UTC+2): 10:00 local == 08:00Z.
+        assertThat(times.dtStartMillis).isEqualTo(1_781_164_800_000L)
+        assertThat(times.dtEndMillis - times.dtStartMillis).isEqualTo(90L * 60L * 1000L)
+        assertThat(times.timezone).isEqualTo("Europe/Berlin")
+    }
+
+    @Test
+    fun `all-day event lives at UTC midnights with exclusive end`() {
+        val times = form(isAllDay = true).toWriteTimes(berlin)
+        assertThat(times.timezone).isEqualTo("UTC")
+        assertThat(times.dtStartMillis % 86_400_000L).isEqualTo(0L)
+        // Single-day all-day event: DTEND is the NEXT UTC midnight.
+        assertThat(times.dtEndMillis - times.dtStartMillis).isEqualTo(86_400_000L)
+    }
+
+    @Test
+    fun `multi-day all-day event spans every covered day`() {
+        val times = form(
+            isAllDay = true,
+            start = LocalDateTime(LocalDate(2026, 6, 11), LocalTime(0, 0)),
+            end = LocalDateTime(LocalDate(2026, 6, 13), LocalTime(0, 0)),
+        ).toWriteTimes(berlin)
+        // 11th, 12th, 13th inclusive = 3 days.
+        assertThat(times.dtEndMillis - times.dtStartMillis).isEqualTo(3L * 86_400_000L)
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/FakeCalendarDataSource.kt

@@ -2,6 +2,7 @@ package de.jeanlucmakiola.calendula.data.calendar
 
 import de.jeanlucmakiola.calendula.domain.CalendarSource
 import de.jeanlucmakiola.calendula.domain.EventDetail
+import de.jeanlucmakiola.calendula.domain.EventForm
 import de.jeanlucmakiola.calendula.domain.EventInstance
 
 /**
@@ -13,6 +14,14 @@ internal class FakeCalendarDataSource : CalendarDataSource {
     var calendarsResult: List<CalendarSource> = emptyList()
     var instancesResult: (Long, Long) -> List<EventInstance> = { _, _ -> emptyList() }
     var eventDetailResult: (Long) -> EventDetail? = { null }
+    /** Set to make the next write call throw. */
+    var writeError: Exception? = null
+    /** Id returned by the next [insertEvent]. */
+    var nextInsertId: Long = 100L
+
+    val insertedForms = mutableListOf<EventForm>()
+    val deletedEventIds = mutableListOf<Long>()
+    val deletedOccurrences = mutableListOf<Pair<Long, Long>>()
 
     private val listeners = mutableListOf<() -> Unit>()
 
@@ -20,6 +29,22 @@ internal class FakeCalendarDataSource : CalendarDataSource {
     override fun instances(beginMillis: Long, endMillis: Long): List<EventInstance> =
         instancesResult(beginMillis, endMillis)
     override fun eventDetail(eventId: Long): EventDetail? = eventDetailResult(eventId)
+
+    override fun insertEvent(form: EventForm): Long {
+        writeError?.let { throw it }
+        insertedForms += form
+        return nextInsertId
+    }
+
+    override fun deleteEvent(eventId: Long) {
+        writeError?.let { throw it }
+        deletedEventIds += eventId
+    }
+
+    override fun deleteOccurrence(eventId: Long, beginMillis: Long) {
+        writeError?.let { throw it }
+        deletedOccurrences += eventId to beginMillis
+    }
     override fun registerChangeListener(listener: () -> Unit) {
         listeners += listener
     }

app/src/test/java/de/jeanlucmakiola/calendula/domain/EventFormTest.kt

@@ -0,0 +1,72 @@
+package de.jeanlucmakiola.calendula.domain
+
+import com.google.common.truth.Truth.assertThat
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
+import org.junit.jupiter.api.Test
+
+class EventFormTest {
+
+    private fun form(
+        calendarId: Long? = 1L,
+        isAllDay: Boolean = false,
+        start: LocalDateTime = LocalDateTime(LocalDate(2026, 6, 11), LocalTime(10, 0)),
+        end: LocalDateTime = LocalDateTime(LocalDate(2026, 6, 11), LocalTime(11, 0)),
+    ): EventForm = EventForm(calendarId = calendarId, isAllDay = isAllDay, start = start, end = end)
+
+    @Test
+    fun `valid timed form has no problems`() {
+        assertThat(form().problems()).isEmpty()
+    }
+
+    @Test
+    fun `missing calendar is a problem`() {
+        assertThat(form(calendarId = null).problems())
+            .containsExactly(EventFormProblem.NoCalendar)
+    }
+
+    @Test
+    fun `timed end before start is a problem`() {
+        val bad = form(end = LocalDateTime(LocalDate(2026, 6, 11), LocalTime(9, 0)))
+        assertThat(bad.problems()).containsExactly(EventFormProblem.EndBeforeStart)
+    }
+
+    @Test
+    fun `zero-length timed event is allowed`() {
+        val instant = form(end = LocalDateTime(LocalDate(2026, 6, 11), LocalTime(10, 0)))
+        assertThat(instant.problems()).isEmpty()
+    }
+
+    @Test
+    fun `all-day single day is allowed even though times match`() {
+        val allDay = form(
+            isAllDay = true,
+            start = LocalDateTime(LocalDate(2026, 6, 11), LocalTime(0, 0)),
+            end = LocalDateTime(LocalDate(2026, 6, 11), LocalTime(0, 0)),
+        )
+        assertThat(allDay.problems()).isEmpty()
+    }
+
+    @Test
+    fun `all-day end date before start date is a problem`() {
+        val bad = form(
+            isAllDay = true,
+            start = LocalDateTime(LocalDate(2026, 6, 11), LocalTime(0, 0)),
+            end = LocalDateTime(LocalDate(2026, 6, 10), LocalTime(0, 0)),
+        )
+        assertThat(bad.problems()).containsExactly(EventFormProblem.EndBeforeStart)
+    }
+
+    @Test
+    fun `problems accumulate`() {
+        val bad = form(
+            calendarId = null,
+            end = LocalDateTime(LocalDate(2026, 6, 11), LocalTime(9, 0)),
+        )
+        assertThat(bad.problems()).containsExactly(
+            EventFormProblem.NoCalendar,
+            EventFormProblem.EndBeforeStart,
+        )
+    }
+}

docs/superpowers/plans/2026-06-11-03-write-support.md

@@ -0,0 +1,109 @@
+# Calendula - Plan 03: Write Support (Milestone 2 / v2.0)
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** Calendula kann Events anlegen, bearbeiten und löschen — direkt über
+`CalendarContract`-Writes, ohne eigene DB. Der V1-Spec dient als Leitplanke,
+nicht als Gesetz: Ausgeliefert wird in vier Slices (v1.1 → v2.0), jeder Slice
+ist für sich releasebar und lässt `./gradlew lint test assembleDebug` grün.
+
+**Architecture:** Writes laufen durch dieselbe Schichtung wie Reads:
+`ui/` → `CalendarRepository` (Interface) → `CalendarDataSource` →
+`ContentResolver.insert/update/delete`. Kein neuer Layer, keine Transaktions-
+Abstraktion — der Provider notified nach jedem Write selbst, der bestehende
+`ContentObserver`-Tick aktualisiert alle Views automatisch (F3 gilt unverändert).
+Domain bleibt pure Kotlin.
+
+**Leitentscheidungen (Abweichungen / Präzisierungen ggü. Spec §2 "V2"):**
+
+1. **Permission-Strategie:** `WRITE_CALENDAR` kommt ins Manifest. Das Onboarding
+   fragt READ+WRITE zusammen an (eine System-Dialog-Gruppe), zwingend bleibt
+   nur READ — wer Write ablehnt, nutzt die App weiter read-only.
+   v1.0-Upgrader (haben nur READ) bekommen den WRITE-Request kontextuell beim
+   ersten Schreib-Versuch. Onboarding-Footnote verliert die "Nur Lesezugriff"-
+   Behauptung (wäre mit Manifest-Eintrag gelogen).
+2. **Read-only-Kalender respektieren:** `Calendars.CALENDAR_ACCESS_LEVEL` wird
+   mitgelesen (`canModifyContents` = Level ≥ `CAL_ACCESS_CONTRIBUTOR`).
+   Edit/Delete-Actions erscheinen gar nicht erst für WebCal-Subscriptions,
+   Geburtstags- und andere read-only-Kalender.
+3. **Recurring Events:** Löschen bietet "Nur dieser Termin" (Exception-Insert
+   via `Events.CONTENT_EXCEPTION_URI` mit `STATUS_CANCELED` +
+   `ORIGINAL_INSTANCE_TIME`) vs. "Ganze Serie" (Delete der Events-Row).
+   Bearbeiten startet mit "ganze Serie"; Occurrence-Edit (Exception mit neuen
+   Werten) folgt erst, wenn das Serien-Edit stabil ist.
+4. **Kein RRULE-Editor in v1.2:** Create startet ohne Wiederholungs-UI
+   (einmalige Events). Ein einfacher Recurrence-Picker (täglich/wöchentlich/
+   monatlich/jährlich + Ende) kommt mit v1.3/v2.0.
+5. **Conflict UX (Spec V2 "event modified externally during edit"):** kein
+   Locking. Beim Speichern wird gegen die beim Laden gemerkte Row verglichen
+   (Dirty-Check auf den editierten Feldern); bei externem Konflikt Dialog
+   "Überschreiben / Verwerfen". Mehr ist YAGNI.
+
+---
+
+## Slices
+
+| Slice | Inhalt | Status |
+|---|---|---|
+| v1.1 | Write-Fundament: `WRITE_CALENDAR`, `canModifyContents`, Delete (Serie + einzelnes Vorkommen) | ausgeliefert (v1.1.0, 2026-06-11) |
+| v1.2 | Create: Event-Formular (Titel, Kalender, ganztägig, Start/Ende, Ort, Beschreibung), FAB, Default-Kalender-Pref | ausgeliefert (v1.2.0, 2026-06-11) |
+| v1.3 | Edit: Formular wiederverwendet, Serien-Edit, Reminder-Edit, einfacher Recurrence-Picker | offen |
+| v2.0 | Quick-Add, Occurrence-Edit, Konflikt-Dialog, Polish-Pass, Release | offen |
+
+## v1.1 — Write-Fundament + Delete
+
+**Build/Manifest:**
+- [x] `AndroidManifest.xml`: `WRITE_CALENDAR` ergänzen
+
+**Data layer:**
+- [x] `Projections.kt`: `CALENDAR_ACCESS_LEVEL` in `CalendarProjection`
+- [x] `Models.kt`: `CalendarSource.canModifyContents: Boolean` (Default `false`).
+      Kein neuer `FailureReason` — Delete-Fehler sind ein Snackbar-Fall, kein
+      Full-Screen-Failure
+- [x] `CalendarMapper.kt`: Access-Level → `canModifyContents`
+- [x] `CalendarDataSource`: `deleteEvent(eventId)`, `deleteOccurrence(eventId, beginMillis)`
+      — Impl in `AndroidCalendarDataSource` (`delete` auf Events-URI bzw.
+      Exception-Insert), `WriteFailedException` bei 0 rows / null-Uri
+- [x] `CalendarRepository(+Impl)`: beide Methoden durchreichen, auf `io`
+
+**UI:**
+- [x] `EventDetailUiState.Success.canModify` (Kalender-Lookup im ViewModel)
+- [x] `EventDetailViewModel`: `delete(mode)` mit eigenem One-Shot-State
+      (Idle/Deleting/Deleted/Failed); `SecurityException` → kontextueller
+      WRITE-Request statt Failure-Screen
+- [x] `EventDetailScreen`: Edit/Delete nur wenn `canModify`; Delete →
+      Confirm-Dialog (recurring: "Nur dieser Termin" / "Ganze Serie"),
+      Erfolg → zurück, Fehler → Snackbar
+- [x] Onboarding (`PermissionScreen`): `RequestMultiplePermissions` READ+WRITE,
+      Gate bleibt READ; Copy-Anpassung (Footnote, Rationale-Body) DE+EN
+
+**Tests:**
+- [x] `FakeCalendarDataSource`: Write-Ops aufnehmen
+- [x] `CalendarRepositoryImplTest`: delete-Pfade (Erfolg, Fehler)
+- [x] `CalendarMapperTest`: Access-Level-Mapping
+
+## v1.2 — Create
+
+- [x] `EventForm`-Domain-Modell + Validierung (`problems()`: EndBeforeStart,
+      NoCalendar; leerer Titel und Instant-Events erlaubt)
+- [x] `EventEditScreen` (ein Formular, ab v1.3 auch für Edit), M3-Date/Time-Picker
+- [x] FAB-Stack auf allen drei Hauptansichten (`CalendarFabColumn`: "+" immer,
+      Heute-Pill darüber), vorbelegt mit dem sichtbaren Tag
+- [x] Kalender-Vorauswahl: explizit > zuletzt benutzt
+      (`CalendarPrefs.lastUsedCalendarId` statt Settings-Eintrag) > erster
+      beschreibbarer; Picker bietet nur beschreibbare Kalender an
+- [x] `insertEvent(form): Long` im DataSource; `EventWriteMapper` (JVM-testbar)
+      normalisiert all-day auf UTC-Mitternächte mit exklusivem DTEND
+
+## v1.3 — Edit (Skizze)
+
+- Formular lädt `EventDetail`, Dirty-Check, `update` auf Events-Row
+- Reminder hinzufügen/entfernen (`Reminders`-Insert/Delete)
+- Einfacher Recurrence-Picker (FREQ + INTERVAL + UNTIL/COUNT)
+
+## v2.0 — Abschluss (Skizze)
+
+- Quick-Add-Sheet (Titel + Zeit, Rest Defaults)
+- Occurrence-Edit (Exception mit geänderten Werten)
+- Konflikt-Dialog beim Speichern
+- Changelog, F-Droid-Metadaten, Release-Tag