style(icon): regenerate F-Droid icon.png to match launcher exactly

Re-render both locale catalog icons (512x512) from the same logo as the
Android adaptive launcher icon, baking in the foreground group transform
(scale 0.5, pivot 114,108, translate 2,8) over the slate background so the
F-Droid render is pixel-faithful to the on-device icon.

Add design/icon/calendula_launcher.svg as the composed full-bleed source
of truth for store/F-Droid renders.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.planning/REQUIREMENTS.md

@@ -10,8 +10,8 @@ See full design spec: `docs/superpowers/specs/2026-06-08-calendar-app-design.md`
 ### Active (V1)
 
 - [x] Foundation & CI infrastructure
-- [ ] Data Layer over `CalendarContract`
+- [x] Data Layer over `CalendarContract`
-- [ ] Permission flow (`READ_CALENDAR`)
+- [x] Permission flow (`READ_CALENDAR`)
 - [ ] Month view (S1)
 - [ ] Week view (S2)
 - [ ] Day view (S3)

.planning/ROADMAP.md

@@ -5,7 +5,7 @@
 | Version | Milestone | Status |
 |---|---|---|
 | v0.1 | Foundation & CI | complete |
-| v0.2 | Data Layer & Permission Flow | pending |
+| v0.2 | Data Layer & Permission Flow | complete |
 | v0.3 | Month view | pending |
 | v0.4 | Week view | pending |
 | v0.5 | Day view | pending |

.planning/STATE.md

@@ -4,19 +4,20 @@
 
 ## Status
 
-**Milestone:** v0.1 — Foundation & CI
+**Milestone:** v0.2 — Data Layer & Permission Flow
-**Phase:** Plan 01 complete; ready to start Plan 02
+**Phase:** Plan 02 complete; UI-design iteration pending before Plan 03
 
 ## Progress
 
 - [x] Design spec written and committed (`docs/superpowers/specs/2026-06-08-calendar-app-design.md`)
 - [x] V1 design decisions resolved (App name "Calendula", icon, seed color)
-- [x] Plan 01 written and executed (`docs/superpowers/plans/2026-06-08-01-foundation.md`)
+- [x] Plan 01 written and executed — foundation lands (theme, icon, i18n, Hilt, DataStore, CI green)
-- [x] Foundation lands: theme, icon, i18n, Hilt, DataStore, CI green
+- [x] Plan 02 written and executed — data layer + permission flow + debug screen
-- [ ] Plan 02 written (Data Layer & Permission Flow)
+- [ ] UI-design iteration (mockups for Month/Week/Day/Detail/Filter/Settings, all three states)
+- [ ] Plan 03 (Month view)
 
 ## Next
 
-1. Write Plan 02: Data Layer & Permission Flow
+1. Iterate on UI design (mockups per screen, all three states)
-2. Execute Plan 02
+2. Write Plan 03: Month view
-3. Iterate on UI design (mockups) before screens are built
+3. Execute Plan 03 — Debug screen gets replaced by month view

CHANGELOG.md

@@ -7,6 +7,37 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.2.1] — 2026-06-09
+
+### Changed
+- Regenerated the F-Droid catalog `icon.png` (512x512, both locales) so it
+  is pixel-faithful to the on-device adaptive launcher icon: same slate
+  background (`#5C6B7A`), off-white mark (`#FAF6F0`), and the foreground
+  group transform (`scale 0.5`, pivot `114,108`, translate `2,8`) baked in.
+- Added `design/icon/calendula_launcher.svg` — the composed full-bleed
+  icon (background + transformed mark) as the single source of truth for
+  store/F-Droid renders.
+
+## [0.2.0] — 2026-06-08
+
+### Added
+- Domain models for calendars, event instances, event detail, attendees
+- `CalendarContract`-backed `CalendarRepository` with `ContentObserver`-driven live updates
+- DataStore preference for app-side hidden-calendar visibility
+- `READ_CALENDAR` permission flow (rationale + denied recovery + system-settings shortcut)
+- Wegwerfbarer Debug-Screen: zeigt alle Kalender + die nächsten 50 Termine ab heute
+- Hilt-Wiring für Data-Layer (Repository, DataSource, DataStore, IO-Dispatcher)
+- Unit-Tests für Cursor-Mapping (alle §8-Defensiv-Cases), Repository-Flows mit Turbine, DataStore round-trip
+- Instrumented smoke test against the real CalendarContract provider
+
+### Changed
+- Redesigned launcher icon: line-art calendar with a stylized "1" inside
+  (kalendae reference) and a small calendula bloom badge in the
+  bottom-right corner. Replaces the simple "1"-only foreground from
+  v0.1.0. Source SVG checked in at `design/icon/calendula_mark.svg`,
+  also used to regenerate the F-Droid catalog `icon.png` (512x512)
+  per locale.
+
 ## [0.1.1] — 2026-06-08
 
 ### Fixed

app/build.gradle.kts

@@ -121,6 +121,7 @@ dependencies {
     androidTestImplementation(libs.androidx.junit)
     androidTestImplementation(libs.androidx.espresso.core)
     androidTestImplementation(libs.androidx.test.rules)
+    androidTestImplementation(libs.truth)
     androidTestImplementation(platform(libs.androidx.compose.bom))
     androidTestImplementation(libs.androidx.ui.test.junit4)
 }

app/src/androidTest/java/de/jeanlucmakiola/calendula/MainActivitySmokeTest.kt

@@ -4,23 +4,27 @@ import androidx.compose.ui.test.assertIsDisplayed
 import androidx.compose.ui.test.junit4.createAndroidComposeRule
 import androidx.compose.ui.test.onNodeWithText
 import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.platform.app.InstrumentationRegistry
 import org.junit.Rule
 import org.junit.Test
 import org.junit.runner.RunWith
 
+/**
+ * Smoke: launches MainActivity and asserts the permission rationale renders
+ * when calendar access has not yet been granted. Without GrantPermissionRule
+ * the system reports NOT_GRANTED on first launch so we land in PermissionScreen.
+ */
 @RunWith(AndroidJUnit4::class)
 class MainActivitySmokeTest {
 
     @get:Rule
     val composeTestRule = createAndroidComposeRule<MainActivity>()
 
-    @Test
+    private val res = InstrumentationRegistry.getInstrumentation().targetContext.resources
-    fun appName_isDisplayed_onLaunch() {
-        composeTestRule.onNodeWithText("Calendula").assertIsDisplayed()
-    }
 
     @Test
-    fun tagline_isDisplayed_onLaunch() {
+    fun permissionRationale_isDisplayed_onLaunch_withoutPermission() {
-        composeTestRule.onNodeWithText("A modern calendar.").assertIsDisplayed()
+        composeTestRule.onNodeWithText(res.getString(R.string.permission_rationale_title))
+            .assertIsDisplayed()
     }
 }

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

@@ -0,0 +1,45 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import android.Manifest
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.rule.GrantPermissionRule
+import com.google.common.truth.Truth.assertThat
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.runBlocking
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import kotlin.time.Instant
+
+@RunWith(AndroidJUnit4::class)
+class CalendarRepositorySmokeTest {
+
+    @get:Rule
+    val permissionRule: GrantPermissionRule =
+        GrantPermissionRule.grant(Manifest.permission.READ_CALENDAR)
+
+    private val context = InstrumentationRegistry.getInstrumentation().targetContext
+
+    private fun newRepo(): CalendarRepositoryImpl {
+        val dataSource = AndroidCalendarDataSource(context)
+        return CalendarRepositoryImpl(dataSource, Dispatchers.IO)
+    }
+
+    @Test
+    fun calendars_returnsListWithoutCrashing() = runBlocking {
+        val repo = newRepo()
+        val first = repo.calendars().first()
+        assertThat(first).isNotNull()
+    }
+
+    @Test
+    fun instances_returnsListWithoutCrashing() = runBlocking {
+        val repo = newRepo()
+        val now = Instant.fromEpochMilliseconds(System.currentTimeMillis())
+        val oneDayLater = Instant.fromEpochMilliseconds(System.currentTimeMillis() + 86_400_000L)
+        val first = repo.instances(now..oneDayLater).first()
+        assertThat(first).isNotNull()
+    }
+}

app/src/androidTest/java/de/jeanlucmakiola/calendula/ui/permission/PermissionScreenTest.kt

@@ -0,0 +1,31 @@
+package de.jeanlucmakiola.calendula.ui.permission
+
+import androidx.compose.ui.test.assertIsDisplayed
+import androidx.compose.ui.test.junit4.createComposeRule
+import androidx.compose.ui.test.onNodeWithText
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.platform.app.InstrumentationRegistry
+import de.jeanlucmakiola.calendula.R
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class PermissionScreenTest {
+
+    @get:Rule
+    val composeTestRule = createComposeRule()
+
+    private val res = InstrumentationRegistry.getInstrumentation().targetContext.resources
+
+    @Test
+    fun rationale_renders_title_and_button() {
+        composeTestRule.setContent {
+            PermissionScreen(onGranted = {})
+        }
+        composeTestRule.onNodeWithText(res.getString(R.string.permission_rationale_title))
+            .assertIsDisplayed()
+        composeTestRule.onNodeWithText(res.getString(R.string.permission_request_button))
+            .assertIsDisplayed()
+    }
+}

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

@@ -4,19 +4,10 @@ import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
-import androidx.compose.foundation.layout.Arrangement
-import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.foundation.layout.padding
-import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.Scaffold
-import androidx.compose.material3.Text
-import androidx.compose.runtime.Composable
-import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
-import androidx.compose.ui.res.stringResource
-import androidx.compose.ui.tooling.preview.Preview
 import dagger.hilt.android.AndroidEntryPoint
+import de.jeanlucmakiola.calendula.ui.RootScreen
 import de.jeanlucmakiola.calendula.ui.theme.CalendulaTheme
 
 @AndroidEntryPoint
@@ -26,34 +17,8 @@ class MainActivity : ComponentActivity() {
         enableEdgeToEdge()
         setContent {
             CalendulaTheme {
-                Scaffold(modifier = Modifier.fillMaxSize()) { innerPadding ->
+                RootScreen(modifier = Modifier.fillMaxSize())
-                    PlaceholderScreen(modifier = Modifier.padding(innerPadding))
-                }
             }
         }
     }
 }
-
-@Composable
-private fun PlaceholderScreen(modifier: Modifier = Modifier) {
-    Column(
-        modifier = modifier.fillMaxSize(),
-        verticalArrangement = Arrangement.Center,
-        horizontalAlignment = Alignment.CenterHorizontally,
-    ) {
-        Text(
-            text = stringResource(R.string.app_name),
-            style = MaterialTheme.typography.displayMedium,
-        )
-        Text(
-            text = stringResource(R.string.app_tagline),
-            style = MaterialTheme.typography.bodyLarge,
-        )
-    }
-}
-
-@Preview(showBackground = true)
-@Composable
-private fun PlaceholderPreview() {
-    CalendulaTheme { PlaceholderScreen() }
-}

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

@@ -0,0 +1,112 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import android.content.ContentResolver
+import android.content.ContentUris
+import android.content.Context
+import android.database.ContentObserver
+import android.database.Cursor
+import android.os.Handler
+import android.os.Looper
+import android.provider.CalendarContract
+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.EventInstance
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Domain-shaped seam over Android's ContentResolver. Returns parsed lists so
+ * the repository can be unit-tested without constructing Cursors or
+ * ContentObservers on the JVM.
+ *
+ * Cursor handling and the ContentObserver-to-listener bridge live entirely
+ * in AndroidCalendarDataSource.
+ */
+interface CalendarDataSource {
+    fun calendars(): List<CalendarSource>
+    fun instances(beginMillis: Long, endMillis: Long): List<EventInstance>
+    fun eventDetail(eventId: Long): EventDetail?
+    fun registerChangeListener(listener: () -> Unit)
+    fun unregisterChangeListener(listener: () -> Unit)
+}
+
+@Singleton
+class AndroidCalendarDataSource @Inject constructor(
+    @ApplicationContext private val context: Context,
+) : CalendarDataSource {
+
+    private val resolver: ContentResolver get() = context.contentResolver
+    private val observers = mutableMapOf<() -> Unit, ContentObserver>()
+
+    override fun calendars(): List<CalendarSource> = resolver.query(
+        CalendarContract.Calendars.CONTENT_URI,
+        CalendarProjection.COLUMNS,
+        null, null,
+        CalendarContract.Calendars.CALENDAR_DISPLAY_NAME + " ASC",
+    )?.use { it.mapAll(::toCalendarSource) } ?: emptyList()
+
+    override fun instances(beginMillis: Long, endMillis: Long): List<EventInstance> {
+        val uri = CalendarContract.Instances.CONTENT_URI.buildUpon().apply {
+            ContentUris.appendId(this, beginMillis)
+            ContentUris.appendId(this, endMillis)
+        }.build()
+        return resolver.query(
+            uri,
+            InstanceProjection.COLUMNS,
+            null, null,
+            CalendarContract.Instances.BEGIN + " ASC",
+        )?.use { c -> c.mapAllNotNull { CursorColumnReader(c).toEventInstance() } } ?: emptyList()
+    }
+
+    override fun eventDetail(eventId: Long): EventDetail? {
+        val attendees = queryAttendees(eventId)
+        return resolver.query(
+            ContentUris.withAppendedId(CalendarContract.Events.CONTENT_URI, eventId),
+            EventDetailProjection.COLUMNS,
+            null, null, null,
+        )?.use { c ->
+            if (!c.moveToFirst()) null
+            else CursorColumnReader(c).toEventDetailCore(attendees)
+        }
+    }
+
+    override fun registerChangeListener(listener: () -> Unit) {
+        val obs = object : ContentObserver(Handler(Looper.getMainLooper())) {
+            override fun onChange(selfChange: Boolean) {
+                listener()
+            }
+        }
+        observers[listener] = obs
+        resolver.registerContentObserver(
+            CalendarContract.CONTENT_URI,
+            /* notifyForDescendants = */ true,
+            obs,
+        )
+    }
+
+    override fun unregisterChangeListener(listener: () -> Unit) {
+        observers.remove(listener)?.let { resolver.unregisterContentObserver(it) }
+    }
+
+    private fun queryAttendees(eventId: Long): List<Attendee> = resolver.query(
+        CalendarContract.Attendees.CONTENT_URI,
+        AttendeeProjection.COLUMNS,
+        CalendarContract.Attendees.EVENT_ID + " = ?",
+        arrayOf(eventId.toString()),
+        null,
+    )?.use { c -> c.mapAll { CursorColumnReader(c).toAttendee() } } ?: emptyList()
+
+    private fun toCalendarSource(c: Cursor): CalendarSource = CursorColumnReader(c).toCalendarSource()
+
+    /** Iterate every row and map; skips nothing. */
+    private inline fun <T> Cursor.mapAll(mapper: (Cursor) -> T): List<T> = buildList {
+        while (moveToNext()) add(mapper(this@mapAll))
+    }
+
+    /** Iterate every row and map; drops nulls. */
+    private inline fun <T : Any> Cursor.mapAllNotNull(mapper: (Cursor) -> T?): List<T> = buildList {
+        while (moveToNext()) mapper(this@mapAllNotNull)?.let(::add)
+    }
+}

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

@@ -0,0 +1,13 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+
+internal fun ColumnReader.toCalendarSource(): CalendarSource = CalendarSource(
+    id = getLong(CalendarProjection.IDX_ID),
+    displayName = getString(CalendarProjection.IDX_DISPLAY_NAME)
+        ?: Fallbacks.UNNAMED_CALENDAR,
+    accountName = getString(CalendarProjection.IDX_ACCOUNT_NAME).orEmpty(),
+    accountType = getString(CalendarProjection.IDX_ACCOUNT_TYPE).orEmpty(),
+    color = getInt(CalendarProjection.IDX_COLOR),
+    isVisibleInSystem = getInt(CalendarProjection.IDX_VISIBLE) != 0,
+)

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

@@ -0,0 +1,16 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventDetail
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import kotlinx.coroutines.flow.Flow
+import kotlin.time.Instant
+
+interface CalendarRepository {
+    fun calendars(): Flow<List<CalendarSource>>
+    fun instances(range: ClosedRange<Instant>): Flow<List<EventInstance>>
+    suspend fun eventDetail(eventId: Long): EventDetail
+}
+
+class NoSuchEventException(eventId: Long) :
+    NoSuchElementException("No event with id=$eventId")

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

@@ -0,0 +1,62 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import de.jeanlucmakiola.calendula.data.di.IoDispatcher
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventDetail
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.flow.onStart
+import kotlinx.coroutines.withContext
+import kotlin.time.Instant
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * One ContentResolver-backed observer for the lifetime of the App process.
+ * Each public flow re-queries on subscribe and after every tick from the
+ * data source.
+ */
+@Singleton
+class CalendarRepositoryImpl @Inject constructor(
+    private val dataSource: CalendarDataSource,
+    @IoDispatcher private val io: CoroutineDispatcher,
+) : CalendarRepository {
+
+    private val ticks = MutableSharedFlow<Unit>(
+        replay = 0,
+        extraBufferCapacity = 1,
+    )
+
+    init {
+        dataSource.registerChangeListener { ticks.tryEmit(Unit) }
+    }
+
+    override fun calendars(): Flow<List<CalendarSource>> =
+        ticks
+            .onStart { emit(Unit) }
+            .reQuery { dataSource.calendars() }
+            .flowOn(io)
+
+    override fun instances(range: ClosedRange<Instant>): Flow<List<EventInstance>> =
+        ticks
+            .onStart { emit(Unit) }
+            .reQuery {
+                dataSource.instances(
+                    beginMillis = range.start.toEpochMillis(),
+                    endMillis = range.endInclusive.toEpochMillis(),
+                )
+            }
+            .flowOn(io)
+
+    override suspend fun eventDetail(eventId: Long): EventDetail = withContext(io) {
+        dataSource.eventDetail(eventId) ?: throw NoSuchEventException(eventId)
+    }
+}
+
+private fun <T> Flow<Unit>.reQuery(block: suspend () -> T): Flow<T> = flow {
+    collect { emit(block()) }
+}

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

@@ -0,0 +1,22 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import android.database.Cursor
+
+/**
+ * Read-only view over a single row's columns by index. Lets the mappers work
+ * on pure-Kotlin test fixtures (MapColumnReader) on the JVM, while the
+ * production path adapts an Android Cursor row via CursorColumnReader.
+ */
+internal interface ColumnReader {
+    fun getLong(index: Int): Long
+    fun getString(index: Int): String?
+    fun getInt(index: Int): Int
+    fun isNull(index: Int): Boolean
+}
+
+internal class CursorColumnReader(private val cursor: Cursor) : ColumnReader {
+    override fun getLong(index: Int): Long = cursor.getLong(index)
+    override fun getString(index: Int): String? = cursor.getString(index)
+    override fun getInt(index: Int): Int = cursor.getInt(index)
+    override fun isNull(index: Int): Boolean = cursor.isNull(index)
+}

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

@@ -0,0 +1,68 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import android.provider.CalendarContract
+import android.util.Log
+import de.jeanlucmakiola.calendula.domain.Attendee
+import de.jeanlucmakiola.calendula.domain.AttendeeStatus
+import de.jeanlucmakiola.calendula.domain.EventDetail
+import de.jeanlucmakiola.calendula.domain.EventInstance
+
+private const val TAG = "EventDetailMapper"
+
+internal fun ColumnReader.toEventDetailCore(attendees: List<Attendee>): EventDetail? {
+    val begin = getLong(EventDetailProjection.IDX_DTSTART)
+    val end = getLong(EventDetailProjection.IDX_DTEND)
+
+    if (begin < 0L) {
+        Log.w(TAG, "Dropping event with negative dtstart=$begin")
+        return null
+    }
+    if (end < begin) {
+        Log.w(TAG, "Dropping event with dtend=$end < dtstart=$begin")
+        return null
+    }
+
+    val rawTitle = getString(EventDetailProjection.IDX_TITLE)
+    val title = if (rawTitle.isNullOrEmpty()) Fallbacks.UNTITLED_EVENT else rawTitle
+
+    val color = if (isNull(EventDetailProjection.IDX_EVENT_COLOR)) {
+        getInt(EventDetailProjection.IDX_CALENDAR_COLOR)
+    } else {
+        getInt(EventDetailProjection.IDX_EVENT_COLOR)
+    }
+
+    val eventId = getLong(EventDetailProjection.IDX_EVENT_ID)
+    val instance = EventInstance(
+        instanceId = eventId,
+        eventId = eventId,
+        calendarId = getLong(EventDetailProjection.IDX_CALENDAR_ID),
+        title = title,
+        start = begin.toKotlinInstantFromEpochMillis(),
+        end = end.toKotlinInstantFromEpochMillis(),
+        isAllDay = getInt(EventDetailProjection.IDX_ALL_DAY) != 0,
+        color = color,
+        location = getString(EventDetailProjection.IDX_LOCATION),
+    )
+
+    return EventDetail(
+        instance = instance,
+        description = getString(EventDetailProjection.IDX_DESCRIPTION),
+        organizer = getString(EventDetailProjection.IDX_ORGANIZER),
+        attendees = attendees,
+        rrule = getString(EventDetailProjection.IDX_RRULE),
+    )
+}
+
+internal fun ColumnReader.toAttendee(): Attendee = Attendee(
+    name = getString(AttendeeProjection.IDX_NAME).orEmpty(),
+    email = getString(AttendeeProjection.IDX_EMAIL),
+    status = mapAttendeeStatus(getInt(AttendeeProjection.IDX_STATUS)),
+)
+
+internal fun mapAttendeeStatus(raw: Int): AttendeeStatus = when (raw) {
+    CalendarContract.Attendees.ATTENDEE_STATUS_ACCEPTED -> AttendeeStatus.Accepted
+    CalendarContract.Attendees.ATTENDEE_STATUS_DECLINED -> AttendeeStatus.Declined
+    CalendarContract.Attendees.ATTENDEE_STATUS_TENTATIVE -> AttendeeStatus.Tentative
+    CalendarContract.Attendees.ATTENDEE_STATUS_INVITED -> AttendeeStatus.NeedsAction
+    else -> AttendeeStatus.Unknown
+}

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

@@ -0,0 +1,41 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import android.util.Log
+import de.jeanlucmakiola.calendula.domain.EventInstance
+
+private const val TAG = "InstanceMapper"
+
+internal fun ColumnReader.toEventInstance(): EventInstance? {
+    val begin = getLong(InstanceProjection.IDX_BEGIN)
+    val end = getLong(InstanceProjection.IDX_END)
+
+    if (begin < 0L) {
+        Log.w(TAG, "Dropping row with negative begin=$begin")
+        return null
+    }
+    if (end < begin) {
+        Log.w(TAG, "Dropping row with end=$end < begin=$begin")
+        return null
+    }
+
+    val rawTitle = getString(InstanceProjection.IDX_TITLE)
+    val title = if (rawTitle.isNullOrEmpty()) Fallbacks.UNTITLED_EVENT else rawTitle
+
+    val color = if (isNull(InstanceProjection.IDX_EVENT_COLOR)) {
+        getInt(InstanceProjection.IDX_CALENDAR_COLOR)
+    } else {
+        getInt(InstanceProjection.IDX_EVENT_COLOR)
+    }
+
+    return EventInstance(
+        instanceId = getLong(InstanceProjection.IDX_INSTANCE_ID),
+        eventId = getLong(InstanceProjection.IDX_EVENT_ID),
+        calendarId = getLong(InstanceProjection.IDX_CALENDAR_ID),
+        title = title,
+        start = begin.toKotlinInstantFromEpochMillis(),
+        end = end.toKotlinInstantFromEpochMillis(),
+        isAllDay = getInt(InstanceProjection.IDX_ALL_DAY) != 0,
+        color = color,
+        location = getString(InstanceProjection.IDX_LOCATION),
+    )
+}

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

@@ -0,0 +1,54 @@
+package de.jeanlucmakiola.calendula.data.di
+
+import android.content.Context
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.preferencesDataStore
+import dagger.Binds
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.InstallIn
+import dagger.hilt.android.qualifiers.ApplicationContext
+import dagger.hilt.components.SingletonComponent
+import de.jeanlucmakiola.calendula.data.calendar.AndroidCalendarDataSource
+import de.jeanlucmakiola.calendula.data.calendar.CalendarDataSource
+import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
+import de.jeanlucmakiola.calendula.data.calendar.CalendarRepositoryImpl
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.Dispatchers
+import javax.inject.Singleton
+
+private val Context.calendulaDataStore: DataStore<Preferences> by preferencesDataStore(
+    name = "calendula_prefs",
+)
+
+@Module
+@InstallIn(SingletonComponent::class)
+abstract class DataBindModule {
+
+    @Binds
+    @Singleton
+    abstract fun bindCalendarDataSource(
+        impl: AndroidCalendarDataSource,
+    ): CalendarDataSource
+
+    @Binds
+    @Singleton
+    abstract fun bindCalendarRepository(
+        impl: CalendarRepositoryImpl,
+    ): CalendarRepository
+}
+
+@Module
+@InstallIn(SingletonComponent::class)
+object DataProvideModule {
+
+    @Provides
+    @Singleton
+    fun provideDataStore(@ApplicationContext context: Context): DataStore<Preferences> =
+        context.calendulaDataStore
+
+    @Provides
+    @IoDispatcher
+    fun provideIoDispatcher(): CoroutineDispatcher = Dispatchers.IO
+}

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

@@ -0,0 +1,7 @@
+package de.jeanlucmakiola.calendula.data.di
+
+import javax.inject.Qualifier
+
+@Qualifier
+@Retention(AnnotationRetention.BINARY)
+annotation class IoDispatcher

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

@@ -0,0 +1,44 @@
+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.stringPreferencesKey
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.map
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * App-side preference for "calendars the user has hidden in this app",
+ * separate from the system's per-calendar VISIBLE flag.
+ *
+ * Persisted as a comma-separated string of Long ids; non-numeric tokens are
+ * silently dropped (defensive — see CalendarPrefsTest).
+ */
+@Singleton
+class CalendarPrefs @Inject constructor(
+    private val store: DataStore<Preferences>,
+) {
+
+    val hiddenCalendarIds: Flow<Set<Long>> = store.data.map { prefs ->
+        prefs[HIDDEN_IDS_KEY].orEmpty()
+            .split(',')
+            .mapNotNull { it.trim().toLongOrNull() }
+            .toSet()
+    }
+
+    suspend fun setHiddenCalendarIds(ids: Set<Long>) {
+        store.edit { prefs ->
+            if (ids.isEmpty()) {
+                prefs.remove(HIDDEN_IDS_KEY)
+            } else {
+                prefs[HIDDEN_IDS_KEY] = ids.sorted().joinToString(",")
+            }
+        }
+    }
+
+    companion object {
+        internal val HIDDEN_IDS_KEY = stringPreferencesKey("hidden_calendar_ids")
+    }
+}

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

@@ -0,0 +1,55 @@
+package de.jeanlucmakiola.calendula.ui
+
+import android.Manifest
+import android.content.pm.PackageManager
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Scaffold
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.lifecycle.compose.LocalLifecycleOwner
+import androidx.core.content.ContextCompat
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleEventObserver
+import de.jeanlucmakiola.calendula.ui.debug.DebugScreen
+import de.jeanlucmakiola.calendula.ui.permission.PermissionScreen
+
+@Composable
+fun RootScreen(modifier: Modifier = Modifier) {
+    val context = LocalContext.current
+    var hasPermission by remember {
+        mutableStateOf(
+            ContextCompat.checkSelfPermission(context, Manifest.permission.READ_CALENDAR)
+                == PackageManager.PERMISSION_GRANTED
+        )
+    }
+
+    val lifecycle = LocalLifecycleOwner.current.lifecycle
+    DisposableEffect(lifecycle) {
+        val obs = LifecycleEventObserver { _, event ->
+            if (event == Lifecycle.Event.ON_RESUME) {
+                hasPermission = ContextCompat.checkSelfPermission(
+                    context, Manifest.permission.READ_CALENDAR
+                ) == PackageManager.PERMISSION_GRANTED
+            }
+        }
+        lifecycle.addObserver(obs)
+        onDispose { lifecycle.removeObserver(obs) }
+    }
+
+    Scaffold(modifier = modifier) { innerPadding ->
+        if (hasPermission) {
+            DebugScreen(modifier = Modifier.padding(innerPadding))
+        } else {
+            PermissionScreen(
+                onGranted = { hasPermission = true },
+                modifier = Modifier.padding(innerPadding),
+            )
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/debug/DebugScreen.kt

@@ -0,0 +1,164 @@
+package de.jeanlucmakiola.calendula.ui.debug
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.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.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.HorizontalDivider
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
+
+@Composable
+fun DebugScreen(
+    modifier: Modifier = Modifier,
+    viewModel: DebugViewModel = hiltViewModel(),
+) {
+    val state by viewModel.state.collectAsStateWithLifecycle()
+    Column(modifier = modifier.fillMaxSize()) {
+        DebugBanner()
+        when (val s = state) {
+            DebugUiState.Loading -> LoadingContent()
+            is DebugUiState.Failure -> FailureContent()
+            is DebugUiState.Success -> SuccessContent(s)
+        }
+    }
+}
+
+@Composable
+private fun DebugBanner() {
+    Box(
+        modifier = Modifier
+            .fillMaxWidth()
+            .background(MaterialTheme.colorScheme.tertiaryContainer)
+            .padding(horizontal = 16.dp, vertical = 8.dp),
+    ) {
+        Text(
+            text = stringResource(R.string.debug_banner),
+            style = MaterialTheme.typography.labelMedium,
+            color = MaterialTheme.colorScheme.onTertiaryContainer,
+        )
+    }
+}
+
+@Composable
+private fun LoadingContent() {
+    Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
+        CircularProgressIndicator()
+    }
+}
+
+@Composable
+private fun FailureContent() {
+    Box(modifier = Modifier.fillMaxSize().padding(24.dp), contentAlignment = Alignment.Center) {
+        Text(
+            text = stringResource(R.string.state_failure_provider),
+            style = MaterialTheme.typography.bodyLarge,
+        )
+    }
+}
+
+@Composable
+private fun SuccessContent(state: DebugUiState.Success) {
+    LazyColumn(
+        modifier = Modifier.fillMaxSize().padding(horizontal = 16.dp),
+        verticalArrangement = Arrangement.spacedBy(4.dp),
+    ) {
+        item { SectionHeader(stringResource(R.string.debug_calendars_header)) }
+        if (state.calendars.isEmpty()) {
+            item {
+                Text(
+                    text = stringResource(R.string.debug_no_calendars),
+                    style = MaterialTheme.typography.bodyMedium,
+                )
+            }
+        } else {
+            items(state.calendars, key = { "cal-${it.id}" }) { CalendarRow(it) }
+        }
+
+        item { Spacer(Modifier.height(16.dp)) }
+        item { SectionHeader(stringResource(R.string.debug_events_header)) }
+
+        if (state.nextEvents.isEmpty()) {
+            item {
+                Text(
+                    text = stringResource(R.string.debug_no_events),
+                    style = MaterialTheme.typography.bodyMedium,
+                )
+            }
+        } else {
+            items(
+                state.nextEvents,
+                // Recurring events share Instances._ID across occurrences, so
+                // include the start instant to keep the LazyColumn key unique.
+                key = { "evt-${it.instanceId}-${it.start.toEpochMilliseconds()}" },
+            ) { EventRow(it) }
+        }
+    }
+}
+
+@Composable
+private fun SectionHeader(text: String) {
+    Column(modifier = Modifier.padding(vertical = 8.dp)) {
+        Text(text = text, style = MaterialTheme.typography.titleMedium)
+        HorizontalDivider()
+    }
+}
+
+@Composable
+private fun CalendarRow(cal: CalendarSource) {
+    Row(
+        modifier = Modifier.fillMaxWidth().padding(vertical = 6.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Box(
+            modifier = Modifier
+                .size(12.dp)
+                .background(Color(cal.color), CircleShape),
+        )
+        Text(
+            text = "  ${cal.displayName}  (${cal.accountName})",
+            style = MaterialTheme.typography.bodyMedium,
+        )
+    }
+}
+
+@Composable
+private fun EventRow(event: EventInstance) {
+    val zone = TimeZone.currentSystemDefault()
+    val start = event.start.toLocalDateTime(zone)
+    Column(modifier = Modifier.fillMaxWidth().padding(vertical = 4.dp)) {
+        Text(text = event.title, style = MaterialTheme.typography.bodyMedium)
+        val date = "%04d-%02d-%02d".format(start.year, start.month.ordinal + 1, start.day)
+        val time = "%02d:%02d".format(start.hour, start.minute)
+        Text(
+            text = "$date  $time",
+            style = MaterialTheme.typography.bodySmall,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+        )
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/debug/DebugUiState.kt

@@ -0,0 +1,14 @@
+package de.jeanlucmakiola.calendula.ui.debug
+
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.domain.FailureReason
+
+sealed interface DebugUiState {
+    data object Loading : DebugUiState
+    data class Failure(val reason: FailureReason) : DebugUiState
+    data class Success(
+        val calendars: List<CalendarSource>,
+        val nextEvents: List<EventInstance>,
+    ) : DebugUiState
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/debug/DebugViewModel.kt

@@ -0,0 +1,49 @@
+package de.jeanlucmakiola.calendula.ui.debug
+
+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.domain.FailureReason
+import kotlinx.coroutines.CoroutineDispatcher
+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.stateIn
+import kotlin.time.Duration.Companion.days
+import kotlin.time.Instant
+import javax.inject.Inject
+
+private const val MAX_DEBUG_EVENTS = 50
+private val DEBUG_WINDOW = 30.days
+
+@HiltViewModel
+class DebugViewModel @Inject constructor(
+    private val repository: CalendarRepository,
+    @IoDispatcher private val io: CoroutineDispatcher,
+) : ViewModel() {
+
+    val state: StateFlow<DebugUiState> = run {
+        val now = Instant.fromEpochMilliseconds(System.currentTimeMillis())
+        val range = now..(now + DEBUG_WINDOW)
+        combine(
+            repository.calendars(),
+            repository.instances(range),
+        ) { calendars, instances ->
+            DebugUiState.Success(
+                calendars = calendars,
+                nextEvents = instances.take(MAX_DEBUG_EVENTS),
+            ) as DebugUiState
+        }
+            .catch { emit(DebugUiState.Failure(FailureReason.ProviderUnavailable)) }
+            .flowOn(io)
+            .stateIn(
+                scope = viewModelScope,
+                started = SharingStarted.WhileSubscribed(5_000L),
+                initialValue = DebugUiState.Loading,
+            )
+    }
+}

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

@@ -0,0 +1,130 @@
+package de.jeanlucmakiola.calendula.ui.permission
+
+import android.Manifest
+import android.content.Intent
+import android.net.Uri
+import android.provider.Settings
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Button
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import de.jeanlucmakiola.calendula.R
+
+@Composable
+fun PermissionScreen(
+    onGranted: () -> Unit,
+    modifier: Modifier = Modifier,
+    viewModel: PermissionViewModel = hiltViewModel(),
+) {
+    val state by viewModel.state.collectAsStateWithLifecycle()
+
+    val launcher = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.RequestPermission(),
+    ) { granted ->
+        if (granted) viewModel.onGranted() else viewModel.onDenied()
+    }
+
+    LaunchedEffect(state) {
+        if (state == PermissionUiState.Granted) onGranted()
+    }
+
+    when (state) {
+        is PermissionUiState.Rationale -> RationaleContent(
+            onRequest = { launcher.launch(Manifest.permission.READ_CALENDAR) },
+            modifier = modifier,
+        )
+        is PermissionUiState.Denied -> DeniedContent(
+            onRetry = {
+                viewModel.onRetry()
+                launcher.launch(Manifest.permission.READ_CALENDAR)
+            },
+            modifier = modifier,
+        )
+        is PermissionUiState.Granted -> {
+            // Transient — LaunchedEffect above fires and parent replaces us.
+        }
+    }
+}
+
+@Composable
+private fun RationaleContent(
+    onRequest: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    Column(
+        modifier = modifier.fillMaxSize().padding(24.dp),
+        verticalArrangement = Arrangement.Center,
+        horizontalAlignment = Alignment.CenterHorizontally,
+    ) {
+        Text(
+            text = stringResource(R.string.permission_rationale_title),
+            style = MaterialTheme.typography.headlineMedium,
+        )
+        Spacer(Modifier.height(16.dp))
+        Text(
+            text = stringResource(R.string.permission_rationale_body),
+            style = MaterialTheme.typography.bodyLarge,
+        )
+        Spacer(Modifier.height(32.dp))
+        Button(onClick = onRequest) {
+            Text(stringResource(R.string.permission_request_button))
+        }
+    }
+}
+
+@Composable
+private fun DeniedContent(
+    onRetry: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    val context = LocalContext.current
+    Column(
+        modifier = modifier.fillMaxSize().padding(24.dp),
+        verticalArrangement = Arrangement.Center,
+        horizontalAlignment = Alignment.CenterHorizontally,
+    ) {
+        Text(
+            text = stringResource(R.string.permission_denied_title),
+            style = MaterialTheme.typography.headlineMedium,
+        )
+        Spacer(Modifier.height(16.dp))
+        Text(
+            text = stringResource(R.string.permission_denied_body),
+            style = MaterialTheme.typography.bodyLarge,
+        )
+        Spacer(Modifier.height(32.dp))
+        Button(onClick = onRetry) {
+            Text(stringResource(R.string.permission_retry_button))
+        }
+        Spacer(Modifier.height(12.dp))
+        OutlinedButton(
+            onClick = {
+                val intent = Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS).apply {
+                    data = Uri.fromParts("package", context.packageName, null)
+                    addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+                }
+                context.startActivity(intent)
+            },
+        ) {
+            Text(stringResource(R.string.permission_open_settings_button))
+        }
+    }
+}

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

@@ -0,0 +1,7 @@
+package de.jeanlucmakiola.calendula.ui.permission
+
+sealed interface PermissionUiState {
+    data object Rationale : PermissionUiState
+    data object Denied : PermissionUiState
+    data object Granted : PermissionUiState
+}

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

@@ -0,0 +1,27 @@
+package de.jeanlucmakiola.calendula.ui.permission
+
+import androidx.lifecycle.ViewModel
+import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import javax.inject.Inject
+
+@HiltViewModel
+class PermissionViewModel @Inject constructor() : ViewModel() {
+
+    private val _state = MutableStateFlow<PermissionUiState>(PermissionUiState.Rationale)
+    val state: StateFlow<PermissionUiState> = _state.asStateFlow()
+
+    fun onGranted() {
+        _state.value = PermissionUiState.Granted
+    }
+
+    fun onDenied() {
+        _state.value = PermissionUiState.Denied
+    }
+
+    fun onRetry() {
+        _state.value = PermissionUiState.Rationale
+    }
+}

app/src/main/res/drawable/ic_launcher_foreground.xml

@@ -1,16 +1,95 @@
 <?xml version="1.0" encoding="utf-8"?>
+<!--
+    Calendula launcher icon foreground.
+
+    Converted from design/icon/calendula_mark.svg (232x232 viewport).
+    Composition: rounded line-art calendar with a stylized "1" inside
+    (referencing kalendae, the Latin word for the first day of the month
+    that is the etymological root of both "calendar" and "calendula"),
+    plus a small Calendula bloom as a badge in the bottom-right corner.
+
+    Strokes render in off-white (#FAF6F0) over the slate background
+    drawable (drawable/ic_launcher_background.xml = @color/ic_launcher_background).
+    The same vector is reused as the <monochrome> slot in the adaptive icon
+    so Android 13+ themed-icon launchers can recolor it from wallpaper.
+-->
 <vector xmlns:android="http://schemas.android.com/apk/res/android"
     android:width="108dp"
     android:height="108dp"
-    android:viewportWidth="108"
+    android:viewportWidth="232"
-    android:viewportHeight="108">
+    android:viewportHeight="232">
     <!--
-        Stylized "1" centered in the 108x108 viewport.
+        Android adaptive icon spec: 108dp canvas.
-        Reference: kalendae (the first day of the month) - etymological root
+
-        of both "Calendar" and "Calendula".
+        Centering Logic:
-        Color is off-white for high contrast on the slate background.
+        - The calendar body is a 142x142 square centered at (114, 108).
+        - The viewport center is (116, 116).
+        - We use pivot (114, 108) and translate by (2, 8) to align the
+          calendar's geometric center perfectly with the canvas center,
+          ignoring the visual weight of the bloom badge.
+
+        Scale:
+        - Scaled by 0.50 to provide significant padding, preventing a
+          "zoomed in" look on home screens and splash screens.
     -->
+    <group
+        android:pivotX="114"
+        android:pivotY="108"
+        android:scaleX="0.50"
+        android:scaleY="0.50"
+        android:translateX="2"
+        android:translateY="8">
+    <!-- Calendar body (rounded square with horizontal header divider) -->
+    <path
+        android:strokeColor="#FFFAF6F0"
+        android:strokeWidth="12"
+        android:strokeLineCap="round"
+        android:strokeLineJoin="round"
+        android:strokeMiterLimit="12"
+        android:pathData="M43,69H185M185,115V63C185,48.64 173.359,37 159,37H69C54.64,37 43,48.64 43,63V153C43,167.359 54.64,179 69,179H124" />
+    <!-- Numeral "1" inside the calendar body -->
+    <path
+        android:strokeColor="#FFFAF6F0"
+        android:strokeWidth="12"
+        android:strokeLineCap="round"
+        android:strokeLineJoin="round"
+        android:pathData="M103,110L113.999,99V142.428" />
+    <!-- Calendula bloom: 8 petals around a filled center -->
+    <path
+        android:strokeColor="#FFFAF6F0"
+        android:strokeWidth="8"
+        android:pathData="M163.072,136.714C163.072,142.886 168.214,153.429 170.786,157.929C173.357,153.429 178.5,142.886 178.5,136.714C178.5,130.543 173.357,129 170.786,129C168.214,129 163.072,130.543 163.072,136.714Z" />
+    <path
+        android:strokeColor="#FFFAF6F0"
+        android:strokeWidth="8"
+        android:pathData="M178.5,186.857C178.5,180.686 173.357,170.143 170.786,165.643C168.214,170.143 163.072,180.686 163.072,186.857C163.072,193.029 168.214,194.572 170.786,194.572C173.357,194.572 178.5,193.029 178.5,186.857Z" />
+    <path
+        android:strokeColor="#FFFAF6F0"
+        android:strokeWidth="8"
+        android:pathData="M195.857,154.072C189.686,154.072 179.143,159.214 174.643,161.786C179.143,164.357 189.686,169.5 195.857,169.5C202.029,169.5 203.572,164.357 203.572,161.786C203.572,159.214 202.029,154.072 195.857,154.072Z" />
+    <path
+        android:strokeColor="#FFFAF6F0"
+        android:strokeWidth="8"
+        android:pathData="M145.714,170.008C151.886,170.008 162.429,164.865 166.929,162.294C162.429,159.722 151.886,154.58 145.714,154.58C139.543,154.58 138,159.722 138,162.294C138,164.865 139.543,170.008 145.714,170.008Z" />
+    <path
+        android:strokeColor="#FFFAF6F0"
+        android:strokeWidth="8"
+        android:pathData="M194.768,174.858C190.404,170.494 179.312,166.676 174.312,165.312C175.676,170.312 179.494,181.404 183.858,185.768C188.222,190.132 192.949,187.586 194.768,185.768C196.586,183.949 199.132,179.222 194.768,174.858Z" />
+    <path
+        android:strokeColor="#FFFAF6F0"
+        android:strokeWidth="8"
+        android:pathData="M146.804,149.222C151.168,153.586 162.259,157.404 167.26,158.768C165.896,153.767 162.077,142.676 157.714,138.312C153.35,133.948 148.622,136.494 146.804,138.312C144.986,140.13 142.44,144.858 146.804,149.222Z" />
+    <path
+        android:strokeColor="#FFFAF6F0"
+        android:strokeWidth="8"
+        android:pathData="M183.858,138.312C179.494,142.676 175.676,153.767 174.312,158.768C179.312,157.404 190.404,153.586 194.768,149.222C199.132,144.858 196.586,140.13 194.768,138.312C192.949,136.494 188.222,133.948 183.858,138.312Z" />
+    <path
+        android:strokeColor="#FFFAF6F0"
+        android:strokeWidth="8"
+        android:pathData="M157.714,185.768C162.077,181.404 165.896,170.312 167.26,165.312C162.259,166.676 151.168,170.494 146.804,174.858C142.44,179.222 144.986,183.949 146.804,185.768C148.622,187.586 153.35,190.132 157.714,185.768Z" />
+    <!-- Calendula center disc -->
     <path
         android:fillColor="#FFFAF6F0"
-        android:pathData="M51.5,38 L51.5,38 C49.5,40 46.5,41.5 43,42.5 L43,49 C46.2,48.2 49,47 51.5,45.5 L51.5,72 L43.5,72 L43.5,76 L65.5,76 L65.5,72 L57.5,72 L57.5,38 Z" />
+        android:pathData="M170.786,169C174.77,169 178,165.77 178,161.786C178,157.802 174.77,154.572 170.786,154.572C166.802,154.572 163.572,157.802 163.572,161.786C163.572,165.77 166.802,169 170.786,169Z" />
+    </group>
 </vector>

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

@@ -10,4 +10,20 @@
     <string name="state_failure_no_calendars">Keine Kalender eingerichtet.</string>
     <string name="state_failure_no_calendars_action">System-Kalender-Einstellungen öffnen</string>
     <string name="state_failure_provider">Kalender konnte nicht gelesen werden.</string>
+
+    <!-- Permission-Flow (F1) -->
+    <string name="permission_rationale_title">Kalender-Zugriff</string>
+    <string name="permission_rationale_body">Calendula liest nur deinen Gerätekalender — keine Daten verlassen das Gerät.</string>
+    <string name="permission_request_button">Weiter</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>
+    <string name="permission_open_settings_button">System-Einstellungen öffnen</string>
+    <string name="permission_retry_button">Erneut versuchen</string>
+
+    <!-- Debug-Screen (wegwerfbar — entfällt mit Plan 03) -->
+    <string name="debug_banner">DEBUG — wird mit Plan 03 durch die Monatsansicht ersetzt</string>
+    <string name="debug_calendars_header">Kalender</string>
+    <string name="debug_events_header">Nächste 50 Termine</string>
+    <string name="debug_no_calendars">Keine Kalender eingerichtet. Füge einen über DAVx5 oder die System-Einstellungen hinzu.</string>
+    <string name="debug_no_events">Keine anstehenden Termine in den nächsten 30 Tagen.</string>
 </resources>

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

@@ -11,4 +11,20 @@
     <string name="state_failure_no_calendars">No calendars configured.</string>
     <string name="state_failure_no_calendars_action">Open system calendar settings</string>
     <string name="state_failure_provider">Could not read the calendar.</string>
+
+    <!-- Permission flow (F1) -->
+    <string name="permission_rationale_title">Calendar access</string>
+    <string name="permission_rationale_body">Calendula reads only your device calendar — no data leaves your device.</string>
+    <string name="permission_request_button">Continue</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>
+    <string name="permission_open_settings_button">Open system settings</string>
+    <string name="permission_retry_button">Try again</string>
+
+    <!-- Debug screen (wegwerfbar — entfällt mit Plan 03) -->
+    <string name="debug_banner">DEBUG — replaced by month view in Plan 03</string>
+    <string name="debug_calendars_header">Calendars</string>
+    <string name="debug_events_header">Next 50 events</string>
+    <string name="debug_no_calendars">No calendars configured. Add one via DAVx5 or system settings.</string>
+    <string name="debug_no_events">No upcoming events in the next 30 days.</string>
 </resources>

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

@@ -0,0 +1,68 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class CalendarMapperTest {
+
+    private fun reader(
+        id: Long = 1L,
+        displayName: String? = "Cal",
+        accountName: String? = "x@y",
+        accountType: String? = "LOCAL",
+        color: Int = 0,
+        visible: Int = 1,
+    ): MapColumnReader = MapColumnReader(
+        CalendarProjection.IDX_ID to id,
+        CalendarProjection.IDX_DISPLAY_NAME to displayName,
+        CalendarProjection.IDX_ACCOUNT_NAME to accountName,
+        CalendarProjection.IDX_ACCOUNT_TYPE to accountType,
+        CalendarProjection.IDX_COLOR to color,
+        CalendarProjection.IDX_VISIBLE to visible,
+    )
+
+    @Test
+    fun `happy path maps all six columns`() {
+        val src = reader(
+            id = 42L,
+            displayName = "Work",
+            accountName = "x@y",
+            accountType = "com.google",
+            color = 0xFF112233.toInt(),
+            visible = 1,
+        ).toCalendarSource()
+        assertThat(src).isEqualTo(
+            de.jeanlucmakiola.calendula.domain.CalendarSource(
+                id = 42L,
+                displayName = "Work",
+                accountName = "x@y",
+                accountType = "com.google",
+                color = 0xFF112233.toInt(),
+                isVisibleInSystem = true,
+            )
+        )
+    }
+
+    @Test
+    fun `null displayName falls back to placeholder`() {
+        val src = reader(displayName = null).toCalendarSource()
+        assertThat(src.displayName).isEqualTo(Fallbacks.UNNAMED_CALENDAR)
+    }
+
+    @Test
+    fun `visible flag 0 maps to false`() {
+        assertThat(reader(visible = 0).toCalendarSource().isVisibleInSystem).isFalse()
+    }
+
+    @Test
+    fun `visible flag 1 maps to true`() {
+        assertThat(reader(visible = 1).toCalendarSource().isVisibleInSystem).isTrue()
+    }
+
+    @Test
+    fun `null accountName and accountType coerce to empty string`() {
+        val src = reader(accountName = null, accountType = null).toCalendarSource()
+        assertThat(src.accountName).isEqualTo("")
+        assertThat(src.accountType).isEqualTo("")
+    }
+}

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

@@ -0,0 +1,111 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import app.cash.turbine.test
+import com.google.common.truth.Truth.assertThat
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.UnconfinedTestDispatcher
+import kotlinx.coroutines.test.runTest
+import kotlin.time.Instant
+import org.junit.jupiter.api.Test
+
+@OptIn(ExperimentalCoroutinesApi::class)
+class CalendarRepositoryImplTest {
+
+    private fun makeCal(id: Long, name: String = "Cal $id"): CalendarSource =
+        CalendarSource(id, name, "x@y", "LOCAL", 0xFF112233.toInt(), true)
+
+    private fun makeEvent(id: Long, title: String = "E $id"): EventInstance = EventInstance(
+        instanceId = id, eventId = id, calendarId = 1L,
+        title = title,
+        start = Instant.fromEpochMilliseconds(1_000_000_000L),
+        end = Instant.fromEpochMilliseconds(1_000_003_600L),
+        isAllDay = false, color = 0xFF000000.toInt(), location = null,
+    )
+
+    @Test
+    fun `calendars emits initial query result on subscribe`() = runTest {
+        val fake = FakeCalendarDataSource().apply {
+            calendarsResult = listOf(makeCal(1L), makeCal(2L))
+        }
+        val repo = CalendarRepositoryImpl(fake, UnconfinedTestDispatcher(testScheduler))
+
+        repo.calendars().test {
+            val first = awaitItem()
+            assertThat(first.map { it.id }).containsExactly(1L, 2L).inOrder()
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
+    @Test
+    fun `calendars re-emits after change listener tick`() = runTest {
+        val fake = FakeCalendarDataSource().apply {
+            calendarsResult = listOf(makeCal(1L))
+        }
+        val repo = CalendarRepositoryImpl(fake, UnconfinedTestDispatcher(testScheduler))
+
+        repo.calendars().test {
+            assertThat(awaitItem().map { it.id }).containsExactly(1L)
+
+            fake.calendarsResult = listOf(makeCal(1L), makeCal(2L))
+            fake.tick()
+
+            assertThat(awaitItem().map { it.id }).containsExactly(1L, 2L).inOrder()
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
+    @Test
+    fun `instances forwards epoch-millis bounds to data source`() = runTest {
+        var observedBegin: Long? = null
+        var observedEnd: Long? = null
+        val fake = FakeCalendarDataSource().apply {
+            instancesResult = {b, e ->
+                observedBegin = b
+                observedEnd = e
+                listOf(makeEvent(10L))
+            }
+        }
+        val repo = CalendarRepositoryImpl(fake, UnconfinedTestDispatcher(testScheduler))
+
+        val range = Instant.fromEpochMilliseconds(1_000L)..Instant.fromEpochMilliseconds(2_000L)
+        repo.instances(range).test {
+            awaitItem()
+            cancelAndIgnoreRemainingEvents()
+        }
+        assertThat(observedBegin).isEqualTo(1_000L)
+        assertThat(observedEnd).isEqualTo(2_000L)
+    }
+
+    @Test
+    fun `instances passes-through whatever the data source returns`() = runTest {
+        val fake = FakeCalendarDataSource().apply {
+            instancesResult = {_, _ -> listOf(makeEvent(10L, "Good")) }
+        }
+        val repo = CalendarRepositoryImpl(fake, UnconfinedTestDispatcher(testScheduler))
+
+        val range = Instant.fromEpochMilliseconds(0)..Instant.fromEpochMilliseconds(10_000L)
+        repo.instances(range).test {
+            val first = awaitItem()
+            assertThat(first.map { it.title }).containsExactly("Good")
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
+    @Test
+    fun `eventDetail throws NoSuchEventException when data source returns null`() = runTest {
+        val fake = FakeCalendarDataSource().apply {
+            eventDetailResult = { null }
+        }
+        val repo = CalendarRepositoryImpl(fake, Dispatchers.Unconfined)
+
+        try {
+            repo.eventDetail(eventId = 999L)
+            error("Expected NoSuchEventException")
+        } catch (expected: NoSuchEventException) {
+            assertThat(expected.message).contains("999")
+        }
+    }
+}

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

@@ -0,0 +1,107 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import com.google.common.truth.Truth.assertThat
+import de.jeanlucmakiola.calendula.domain.AttendeeStatus
+import org.junit.jupiter.api.Test
+
+class EventDetailMapperTest {
+
+    private fun detailReader(
+        eventId: Long = 1L,
+        title: String? = "Meet",
+        description: String? = "Body",
+        organizer: String? = "x@y",
+        rrule: String? = null,
+        eventColor: Any? = null,
+        calendarColor: Int = 0xFFAABBCC.toInt(),
+        dtstart: Long = 1_000_000_000L,
+        dtend: Long = 1_000_003_600L,
+        allDay: Int = 0,
+        location: String? = "Berlin",
+        calendarId: Long = 7L,
+    ): MapColumnReader = MapColumnReader(
+        EventDetailProjection.IDX_EVENT_ID to eventId,
+        EventDetailProjection.IDX_TITLE to title,
+        EventDetailProjection.IDX_DESCRIPTION to description,
+        EventDetailProjection.IDX_ORGANIZER to organizer,
+        EventDetailProjection.IDX_RRULE to rrule,
+        EventDetailProjection.IDX_EVENT_COLOR to eventColor,
+        EventDetailProjection.IDX_CALENDAR_COLOR to calendarColor,
+        EventDetailProjection.IDX_DTSTART to dtstart,
+        EventDetailProjection.IDX_DTEND to dtend,
+        EventDetailProjection.IDX_ALL_DAY to allDay,
+        EventDetailProjection.IDX_LOCATION to location,
+        EventDetailProjection.IDX_CALENDAR_ID to calendarId,
+    )
+
+    private fun attendeeReader(name: String?, email: String?, status: Int): MapColumnReader =
+        MapColumnReader(
+            AttendeeProjection.IDX_NAME to name,
+            AttendeeProjection.IDX_EMAIL to email,
+            AttendeeProjection.IDX_STATUS to status,
+        )
+
+    @Test
+    fun `happy path detail maps all fields and embeds matching EventInstance`() {
+        val detail = detailReader().toEventDetailCore(attendees = emptyList())
+        assertThat(detail).isNotNull()
+        assertThat(detail!!.description).isEqualTo("Body")
+        assertThat(detail.organizer).isEqualTo("x@y")
+        assertThat(detail.instance.title).isEqualTo("Meet")
+        assertThat(detail.instance.location).isEqualTo("Berlin")
+        assertThat(detail.attendees).isEmpty()
+    }
+
+    @Test
+    fun `event color falls back to calendar color when null`() {
+        val detail = detailReader(eventColor = null, calendarColor = 0xFF112233.toInt())
+            .toEventDetailCore(attendees = emptyList())
+        assertThat(detail!!.instance.color).isEqualTo(0xFF112233.toInt())
+    }
+
+    @Test
+    fun `dtend before dtstart drops detail`() {
+        val detail = detailReader(dtstart = 2000L, dtend = 1000L)
+            .toEventDetailCore(attendees = emptyList())
+        assertThat(detail).isNull()
+    }
+
+    @Test
+    fun `rrule passes through when present`() {
+        val detail = detailReader(rrule = "FREQ=WEEKLY;BYDAY=MO")
+            .toEventDetailCore(attendees = emptyList())
+        assertThat(detail!!.rrule).isEqualTo("FREQ=WEEKLY;BYDAY=MO")
+    }
+
+    // Raw CalendarContract.Attendees status integer constants from the Android
+    // source (kept inline so the test doesn't depend on the mockable.jar's
+    // possibly-stubbed constants):
+    // ACCEPTED=1, DECLINED=2, INVITED=3, TENTATIVE=4, NONE=0
+    @Test
+    fun `attendee status maps known integer codes`() {
+        assertThat(attendeeReader("A", "a@x", 1).toAttendee().status)
+            .isEqualTo(AttendeeStatus.Accepted)
+        assertThat(attendeeReader("B", "b@x", 2).toAttendee().status)
+            .isEqualTo(AttendeeStatus.Declined)
+        assertThat(attendeeReader("C", "c@x", 4).toAttendee().status)
+            .isEqualTo(AttendeeStatus.Tentative)
+        assertThat(attendeeReader("D", "d@x", 3).toAttendee().status)
+            .isEqualTo(AttendeeStatus.NeedsAction)
+        assertThat(attendeeReader("E", "e@x", 0).toAttendee().status)
+            .isEqualTo(AttendeeStatus.Unknown)
+        assertThat(attendeeReader("F", "f@x", 99).toAttendee().status)
+            .isEqualTo(AttendeeStatus.Unknown)
+    }
+
+    @Test
+    fun `attendee with null name maps to empty string`() {
+        val a = attendeeReader(null, "alice@x", 1).toAttendee()
+        assertThat(a.name).isEqualTo("")
+    }
+
+    @Test
+    fun `attendee email passes through nullably`() {
+        assertThat(attendeeReader("A", null, 1).toAttendee().email).isNull()
+        assertThat(attendeeReader("A", "x@y", 1).toAttendee().email).isEqualTo("x@y")
+    }
+}

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

@@ -0,0 +1,33 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventDetail
+import de.jeanlucmakiola.calendula.domain.EventInstance
+
+/**
+ * Test-only fake. Tunable via the three `var` properties; `tick()` simulates
+ * a provider change so the repository re-queries.
+ */
+internal class FakeCalendarDataSource : CalendarDataSource {
+
+    var calendarsResult: List<CalendarSource> = emptyList()
+    var instancesResult: (Long, Long) -> List<EventInstance> = { _, _ -> emptyList() }
+    var eventDetailResult: (Long) -> EventDetail? = { null }
+
+    private val listeners = mutableListOf<() -> Unit>()
+
+    override fun calendars(): List<CalendarSource> = calendarsResult
+    override fun instances(beginMillis: Long, endMillis: Long): List<EventInstance> =
+        instancesResult(beginMillis, endMillis)
+    override fun eventDetail(eventId: Long): EventDetail? = eventDetailResult(eventId)
+    override fun registerChangeListener(listener: () -> Unit) {
+        listeners += listener
+    }
+    override fun unregisterChangeListener(listener: () -> Unit) {
+        listeners -= listener
+    }
+
+    fun tick() {
+        listeners.forEach { it() }
+    }
+}

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

@@ -0,0 +1,93 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import com.google.common.truth.Truth.assertThat
+import kotlin.time.Instant
+import org.junit.jupiter.api.Test
+
+class InstanceMapperTest {
+
+    private fun reader(
+        instanceId: Long = 10L,
+        eventId: Long = 1L,
+        calendarId: Long = 1L,
+        title: String? = "Meet",
+        begin: Long = 1_000_000_000L,
+        end: Long = 1_000_003_600L,
+        allDay: Int = 0,
+        eventColor: Any? = null,
+        calendarColor: Int = 0xFFAABBCC.toInt(),
+        location: String? = null,
+    ): MapColumnReader = MapColumnReader(
+        InstanceProjection.IDX_INSTANCE_ID to instanceId,
+        InstanceProjection.IDX_EVENT_ID to eventId,
+        InstanceProjection.IDX_CALENDAR_ID to calendarId,
+        InstanceProjection.IDX_TITLE to title,
+        InstanceProjection.IDX_BEGIN to begin,
+        InstanceProjection.IDX_END to end,
+        InstanceProjection.IDX_ALL_DAY to allDay,
+        InstanceProjection.IDX_EVENT_COLOR to eventColor,
+        InstanceProjection.IDX_CALENDAR_COLOR to calendarColor,
+        InstanceProjection.IDX_LOCATION to location,
+    )
+
+    @Test
+    fun `happy path - non-allday event`() {
+        val inst = reader().toEventInstance()
+        assertThat(inst).isNotNull()
+        assertThat(inst!!.title).isEqualTo("Meet")
+        assertThat(inst.isAllDay).isFalse()
+        assertThat(inst.start).isEqualTo(Instant.fromEpochMilliseconds(1_000_000_000L))
+        assertThat(inst.end).isEqualTo(Instant.fromEpochMilliseconds(1_000_003_600L))
+    }
+
+    @Test
+    fun `event color falls back to calendar color when null`() {
+        val inst = reader(eventColor = null, calendarColor = 0xFF112233.toInt()).toEventInstance()
+        assertThat(inst!!.color).isEqualTo(0xFF112233.toInt())
+    }
+
+    @Test
+    fun `event color wins over calendar color when present`() {
+        val inst = reader(
+            eventColor = 0xFFDEADBE.toInt(),
+            calendarColor = 0xFF112233.toInt(),
+        ).toEventInstance()
+        assertThat(inst!!.color).isEqualTo(0xFFDEADBE.toInt())
+    }
+
+    @Test
+    fun `null title falls back to placeholder`() {
+        val inst = reader(title = null).toEventInstance()
+        assertThat(inst!!.title).isEqualTo(Fallbacks.UNTITLED_EVENT)
+    }
+
+    @Test
+    fun `empty title falls back to placeholder`() {
+        val inst = reader(title = "").toEventInstance()
+        assertThat(inst!!.title).isEqualTo(Fallbacks.UNTITLED_EVENT)
+    }
+
+    @Test
+    fun `dtend before dtstart drops the row`() {
+        val inst = reader(begin = 2000L, end = 1000L).toEventInstance()
+        assertThat(inst).isNull()
+    }
+
+    @Test
+    fun `dtstart before unix epoch drops the row`() {
+        val inst = reader(begin = -1L, end = 1000L).toEventInstance()
+        assertThat(inst).isNull()
+    }
+
+    @Test
+    fun `all-day flag 1 maps to true`() {
+        val inst = reader(allDay = 1).toEventInstance()
+        assertThat(inst!!.isAllDay).isTrue()
+    }
+
+    @Test
+    fun `location passes through when present`() {
+        val inst = reader(location = "Berlin").toEventInstance()
+        assertThat(inst!!.location).isEqualTo("Berlin")
+    }
+}

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

@@ -0,0 +1,29 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+/**
+ * Test-only ColumnReader. Backed by a Map<Int, Any?>; any missing index is
+ * treated as null. Numeric getters coerce via toLong/toInt; non-numeric values
+ * yield zero (matching Android Cursor behavior for type-mismatched reads).
+ */
+internal class MapColumnReader(values: Map<Int, Any?>) : ColumnReader {
+
+    private val data: Map<Int, Any?> = values
+
+    constructor(vararg pairs: Pair<Int, Any?>) : this(pairs.toMap())
+
+    override fun getLong(index: Int): Long = when (val v = data[index]) {
+        is Number -> v.toLong()
+        is String -> v.toLongOrNull() ?: 0L
+        else -> 0L
+    }
+
+    override fun getString(index: Int): String? = data[index]?.toString()
+
+    override fun getInt(index: Int): Int = when (val v = data[index]) {
+        is Number -> v.toInt()
+        is String -> v.toIntOrNull() ?: 0
+        else -> 0
+    }
+
+    override fun isNull(index: Int): Boolean = data[index] == null
+}

app/src/test/java/de/jeanlucmakiola/calendula/data/prefs/CalendarPrefsTest.kt

@@ -0,0 +1,53 @@
+package de.jeanlucmakiola.calendula.data.prefs
+
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.PreferenceDataStoreFactory
+import androidx.datastore.preferences.core.Preferences
+import com.google.common.truth.Truth.assertThat
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.test.runTest
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.io.TempDir
+import java.nio.file.Path
+
+class CalendarPrefsTest {
+
+    private fun newDataStore(tempDir: Path): DataStore<Preferences> =
+        PreferenceDataStoreFactory.create(
+            produceFile = { tempDir.resolve("test_prefs.preferences_pb").toFile() },
+        )
+
+    @Test
+    fun `hiddenCalendarIds defaults to empty when unset`(@TempDir tempDir: Path) = runTest {
+        val prefs = CalendarPrefs(newDataStore(tempDir))
+        assertThat(prefs.hiddenCalendarIds.first()).isEmpty()
+    }
+
+    @Test
+    fun `setHiddenCalendarIds round-trips through DataStore`(@TempDir tempDir: Path) = runTest {
+        val store = newDataStore(tempDir)
+        val prefs = CalendarPrefs(store)
+        prefs.setHiddenCalendarIds(setOf(1L, 42L, 7L))
+        assertThat(prefs.hiddenCalendarIds.first()).isEqualTo(setOf(1L, 42L, 7L))
+    }
+
+    @Test
+    fun `setting empty set clears storage`(@TempDir tempDir: Path) = runTest {
+        val prefs = CalendarPrefs(newDataStore(tempDir))
+        prefs.setHiddenCalendarIds(setOf(1L))
+        prefs.setHiddenCalendarIds(emptySet())
+        assertThat(prefs.hiddenCalendarIds.first()).isEmpty()
+    }
+
+    @Test
+    fun `garbage stored string is parsed defensively`(@TempDir tempDir: Path) = runTest {
+        val store = newDataStore(tempDir)
+        val prefs = CalendarPrefs(store)
+        store.updateData { p ->
+            val mutable = p.toMutablePreferences()
+            mutable[CalendarPrefs.HIDDEN_IDS_KEY] = "1,abc,3"
+            mutable
+        }
+        assertThat(prefs.hiddenCalendarIds.first()).isEqualTo(setOf(1L, 3L))
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/ui/debug/DebugViewModelTest.kt

@@ -0,0 +1,114 @@
+package de.jeanlucmakiola.calendula.ui.debug
+
+import app.cash.turbine.test
+import com.google.common.truth.Truth.assertThat
+import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
+import de.jeanlucmakiola.calendula.data.calendar.NoSuchEventException
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventDetail
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.test.UnconfinedTestDispatcher
+import kotlinx.coroutines.test.resetMain
+import kotlinx.coroutines.test.runTest
+import kotlinx.coroutines.test.setMain
+import kotlin.time.Instant
+import org.junit.jupiter.api.AfterEach
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+
+@OptIn(ExperimentalCoroutinesApi::class)
+class DebugViewModelTest {
+
+    private val testDispatcher = UnconfinedTestDispatcher()
+
+    @BeforeEach
+    fun setUp() {
+        Dispatchers.setMain(testDispatcher)
+    }
+
+    @AfterEach
+    fun tearDown() {
+        Dispatchers.resetMain()
+    }
+
+    private class FakeRepo(
+        val calendarsFlow: MutableStateFlow<List<CalendarSource>> = MutableStateFlow(emptyList()),
+        val instancesFlow: MutableStateFlow<List<EventInstance>> = MutableStateFlow(emptyList()),
+    ) : CalendarRepository {
+        override fun calendars(): Flow<List<CalendarSource>> = calendarsFlow
+        override fun instances(range: ClosedRange<Instant>): Flow<List<EventInstance>> = instancesFlow
+        override suspend fun eventDetail(eventId: Long): EventDetail =
+            throw NoSuchEventException(eventId)
+    }
+
+    private fun makeCal(id: Long, name: String = "C $id"): CalendarSource =
+        CalendarSource(id, name, "x@y", "LOCAL", 0xFF112233.toInt(), true)
+
+    private fun makeEvent(id: Long, title: String = "E $id") = EventInstance(
+        instanceId = id, eventId = id, calendarId = 1L,
+        title = title,
+        start = Instant.fromEpochMilliseconds(0L),
+        end = Instant.fromEpochMilliseconds(60_000L),
+        isAllDay = false, color = 0xFF000000.toInt(), location = null,
+    )
+
+    @Test
+    fun `initial state value is Loading before any subscriber`() {
+        val repo = FakeRepo()
+        val vm = DebugViewModel(repo, testDispatcher)
+        assertThat(vm.state.value).isEqualTo(DebugUiState.Loading)
+    }
+
+    @Test
+    fun `Success contains calendars and capped events after subscription`() = runTest {
+        val repo = FakeRepo(
+            calendarsFlow = MutableStateFlow(listOf(makeCal(1L))),
+            instancesFlow = MutableStateFlow(listOf(makeEvent(10L, "X"))),
+        )
+        val vm = DebugViewModel(repo, testDispatcher)
+        vm.state.test {
+            val success = awaitItem() as DebugUiState.Success
+            assertThat(success.calendars.map { it.id }).containsExactly(1L)
+            assertThat(success.nextEvents.map { it.title }).containsExactly("X")
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
+    @Test
+    fun `instances are capped at 50`() = runTest {
+        val repo = FakeRepo(
+            calendarsFlow = MutableStateFlow(listOf(makeCal(1L))),
+            instancesFlow = MutableStateFlow((1L..100L).map { makeEvent(it, "E$it") }),
+        )
+        val vm = DebugViewModel(repo, testDispatcher)
+        vm.state.test {
+            val success = awaitItem() as DebugUiState.Success
+            assertThat(success.nextEvents).hasSize(50)
+            assertThat(success.nextEvents.first().instanceId).isEqualTo(1L)
+            assertThat(success.nextEvents.last().instanceId).isEqualTo(50L)
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
+    @Test
+    fun `state updates when repository emits new data`() = runTest {
+        val repo = FakeRepo()
+        val vm = DebugViewModel(repo, testDispatcher)
+        vm.state.test {
+            // Empty initial: combine fires once because both StateFlows have initial empty value
+            val empty = awaitItem() as DebugUiState.Success
+            assertThat(empty.calendars).isEmpty()
+            assertThat(empty.nextEvents).isEmpty()
+
+            repo.calendarsFlow.value = listOf(makeCal(1L), makeCal(2L))
+            val updated = awaitItem() as DebugUiState.Success
+            assertThat(updated.calendars.map { it.id }).containsExactly(1L, 2L).inOrder()
+
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+}

design/icon/calendula_launcher.svg

@@ -0,0 +1,34 @@
+<svg width="232" height="232" viewBox="0 0 232 232" xmlns="http://www.w3.org/2000/svg">
+<!--
+    Composed Calendula launcher icon (full-bleed), generated to exactly match the
+    Android adaptive icon defined by:
+      - drawable/ic_launcher_background.xml  (solid @color/ic_launcher_background = #5C6B7A)
+      - drawable/ic_launcher_foreground.xml  (off-white #FAF6F0 mark from calendula_mark.svg)
+
+    The adaptive foreground group transform (scaleX/Y=0.50, pivot 114,108,
+    translate 2,8) is reproduced here as the SVG transform "translate(59,62) scale(0.5)"
+    because Android applies it as:  p' = scale*p + pivot*(1-scale) + translate
+      x' = 0.5*x + 114*0.5 + 2 = 0.5*x + 59
+      y' = 0.5*y + 108*0.5 + 8 = 0.5*y + 62
+
+    This is the single source of truth for the F-Droid / store icon.png renders.
+-->
+<rect x="0" y="0" width="232" height="232" fill="#5C6B7A"/>
+<g transform="translate(59,62) scale(0.5)" fill="none" stroke="#FAF6F0">
+  <!-- Calendar body (rounded square with horizontal header divider) -->
+  <path d="M43 69H185M185 115V63C185 48.64 173.359 37 159 37H69C54.64 37 43 48.64 43 63V153C43 167.359 54.64 179 69 179H124" stroke-width="12" stroke-miterlimit="12" stroke-linecap="round" stroke-linejoin="round"/>
+  <!-- Numeral "1" inside the calendar body -->
+  <path d="M103 110L113.999 99V142.428" stroke-width="12" stroke-linecap="round" stroke-linejoin="round"/>
+  <!-- Calendula bloom: 8 petals around a filled center -->
+  <path d="M163.072 136.714C163.072 142.886 168.214 153.429 170.786 157.929C173.357 153.429 178.5 142.886 178.5 136.714C178.5 130.543 173.357 129 170.786 129C168.214 129 163.072 130.543 163.072 136.714Z" stroke-width="8"/>
+  <path d="M178.5 186.857C178.5 180.686 173.357 170.143 170.786 165.643C168.214 170.143 163.072 180.686 163.072 186.857C163.072 193.029 168.214 194.572 170.786 194.572C173.357 194.572 178.5 193.029 178.5 186.857Z" stroke-width="8"/>
+  <path d="M195.857 154.072C189.686 154.072 179.143 159.214 174.643 161.786C179.143 164.357 189.686 169.5 195.857 169.5C202.029 169.5 203.572 164.357 203.572 161.786C203.572 159.214 202.029 154.072 195.857 154.072Z" stroke-width="8"/>
+  <path d="M145.714 170.008C151.886 170.008 162.429 164.865 166.929 162.294C162.429 159.722 151.886 154.58 145.714 154.58C139.543 154.58 138 159.722 138 162.294C138 164.865 139.543 170.008 145.714 170.008Z" stroke-width="8"/>
+  <path d="M194.768 174.858C190.404 170.494 179.312 166.676 174.312 165.312C175.676 170.312 179.494 181.404 183.858 185.768C188.222 190.132 192.949 187.586 194.768 185.768C196.586 183.949 199.132 179.222 194.768 174.858Z" stroke-width="8"/>
+  <path d="M146.804 149.222C151.168 153.586 162.259 157.404 167.26 158.768C165.896 153.767 162.077 142.676 157.714 138.312C153.35 133.948 148.622 136.494 146.804 138.312C144.986 140.13 142.44 144.858 146.804 149.222Z" stroke-width="8"/>
+  <path d="M183.858 138.312C179.494 142.676 175.676 153.767 174.312 158.768C179.312 157.404 190.404 153.586 194.768 149.222C199.132 144.858 196.586 140.13 194.768 138.312C192.949 136.494 188.222 133.948 183.858 138.312Z" stroke-width="8"/>
+  <path d="M157.714 185.768C162.077 181.404 165.896 170.312 167.26 165.312C162.259 166.676 151.168 170.494 146.804 174.858C142.44 179.222 144.986 183.949 146.804 185.768C148.622 187.586 153.35 190.132 157.714 185.768Z" stroke-width="8"/>
+  <!-- Calendula center disc (filled, matches foreground <fillColor> slot) -->
+  <path d="M170.786 169C174.77 169 178 165.77 178 161.786C178 157.802 174.77 154.572 170.786 154.572C166.802 154.572 163.572 157.802 163.572 161.786C163.572 165.77 166.802 169 170.786 169Z" fill="#FAF6F0" stroke="none"/>
+</g>
+</svg>

design/icon/calendula_mark.svg

@@ -0,0 +1,13 @@
+<svg width="232" height="232" viewBox="0 0 232 232" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M43 69H185M185 115V63C185 48.64 173.359 37 159 37H69C54.64 37 43 48.64 43 63V153C43 167.359 54.64 179 69 179H124" stroke="black" stroke-width="12" stroke-miterlimit="12" stroke-linecap="round" stroke-linejoin="round"/>
+<path d="M103 110L113.999 99V142.428" stroke="black" stroke-width="12" stroke-linecap="round" stroke-linejoin="round"/>
+<path d="M163.072 136.714C163.072 142.886 168.214 153.429 170.786 157.929C173.357 153.429 178.5 142.886 178.5 136.714C178.5 130.543 173.357 129 170.786 129C168.214 129 163.072 130.543 163.072 136.714Z" stroke="black" stroke-width="8"/>
+<path d="M178.5 186.857C178.5 180.686 173.357 170.143 170.786 165.643C168.214 170.143 163.072 180.686 163.072 186.857C163.072 193.029 168.214 194.572 170.786 194.572C173.357 194.572 178.5 193.029 178.5 186.857Z" stroke="black" stroke-width="8"/>
+<path d="M195.857 154.072C189.686 154.072 179.143 159.214 174.643 161.786C179.143 164.357 189.686 169.5 195.857 169.5C202.029 169.5 203.572 164.357 203.572 161.786C203.572 159.214 202.029 154.072 195.857 154.072Z" stroke="black" stroke-width="8"/>
+<path d="M145.714 170.008C151.886 170.008 162.429 164.865 166.929 162.294C162.429 159.722 151.886 154.58 145.714 154.58C139.543 154.58 138 159.722 138 162.294C138 164.865 139.543 170.008 145.714 170.008Z" stroke="black" stroke-width="8"/>
+<path d="M194.768 174.858C190.404 170.494 179.312 166.676 174.312 165.312C175.676 170.312 179.494 181.404 183.858 185.768C188.222 190.132 192.949 187.586 194.768 185.768C196.586 183.949 199.132 179.222 194.768 174.858Z" stroke="black" stroke-width="8"/>
+<path d="M146.804 149.222C151.168 153.586 162.259 157.404 167.26 158.768C165.896 153.767 162.077 142.676 157.714 138.312C153.35 133.948 148.622 136.494 146.804 138.312C144.986 140.13 142.44 144.858 146.804 149.222Z" stroke="black" stroke-width="8"/>
+<path d="M183.858 138.312C179.494 142.676 175.676 153.767 174.312 158.768C179.312 157.404 190.404 153.586 194.768 149.222C199.132 144.858 196.586 140.13 194.768 138.312C192.949 136.494 188.222 133.948 183.858 138.312Z" stroke="black" stroke-width="8"/>
+<path d="M157.714 185.768C162.077 181.404 165.896 170.312 167.26 165.312C162.259 166.676 151.168 170.494 146.804 174.858C142.44 179.222 144.986 183.949 146.804 185.768C148.622 187.586 153.35 190.132 157.714 185.768Z" stroke="black" stroke-width="8"/>
+<path d="M170.786 169C174.77 169 178 165.77 178 161.786C178 157.802 174.77 154.572 170.786 154.572C166.802 154.572 163.572 157.802 163.572 161.786C163.572 165.77 166.802 169 170.786 169Z" fill="black" stroke="black"/>
+</svg>

gradle/gradle-daemon-jvm.properties

@@ -0,0 +1,13 @@
+#This file is generated by updateDaemonJvm
+toolchainUrl.FREE_BSD.AARCH64=https\://api.foojay.io/disco/v3.0/ids/491f83666ae7f4d6ebb28fee72ebb035/redirect
+toolchainUrl.FREE_BSD.X86_64=https\://api.foojay.io/disco/v3.0/ids/0d1a1acdc708062093673f65aa9aba4b/redirect
+toolchainUrl.LINUX.AARCH64=https\://api.foojay.io/disco/v3.0/ids/491f83666ae7f4d6ebb28fee72ebb035/redirect
+toolchainUrl.LINUX.X86_64=https\://api.foojay.io/disco/v3.0/ids/0d1a1acdc708062093673f65aa9aba4b/redirect
+toolchainUrl.MAC_OS.AARCH64=https\://api.foojay.io/disco/v3.0/ids/7083b89563e7ce20943037b8cd2b8cc2/redirect
+toolchainUrl.MAC_OS.X86_64=https\://api.foojay.io/disco/v3.0/ids/060bbb778a1f55ea705fdebd2ccfeab9/redirect
+toolchainUrl.UNIX.AARCH64=https\://api.foojay.io/disco/v3.0/ids/491f83666ae7f4d6ebb28fee72ebb035/redirect
+toolchainUrl.UNIX.X86_64=https\://api.foojay.io/disco/v3.0/ids/0d1a1acdc708062093673f65aa9aba4b/redirect
+toolchainUrl.WINDOWS.AARCH64=https\://api.foojay.io/disco/v3.0/ids/d09679dc60fe5aa05ef7d03efdefac20/redirect
+toolchainUrl.WINDOWS.X86_64=https\://api.foojay.io/disco/v3.0/ids/ed4e3bf2f5e7c5d9aabc4cbd8acd555e/redirect
+toolchainVendor=JETBRAINS
+toolchainVersion=21

gradle/libs.versions.toml

@@ -1,5 +1,5 @@
 [versions]
-agp = "9.1.1"
+agp = "9.2.1"
 kotlin = "2.3.21"
 ksp = "2.3.9"
 hilt = "2.59.2"

settings.gradle.kts

@@ -11,6 +11,9 @@ pluginManagement {
         gradlePluginPortal()
     }
 }
+plugins {
+    id("org.gradle.toolchains.foojay-resolver-convention") version "1.0.0"
+}
 
 dependencyResolutionManagement {
     repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)