feat: import birthdays from Android Contacts

Mirror the iOS Contacts birthday importer: read the address book's birthday
events and reconcile them into the user's birthday calendar, scoped to this
device via external_uid 'contact:<deviceId>:<contactId>' (add/update/delete),
then report the device.

- READ_CONTACTS permission + ContactsReader (Event TYPE_BIRTHDAY, handles
  year/no-year date formats)
- API: GET /birthdays, POST /birthdays/sync-report; local-event create/update
  now carry external_uid (+ update carries rrule/birth_year)
- CalendarViewModel.syncContactBirthdays reconciles like iOS; device-local
  enable flag + stable device id in SettingsStore
- birthday dialog gains an 'Import from contacts' action (requests permission);
  auto-syncs on launch when enabled

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

app/src/main/java/com/scarriffle/calendarr/data/CalendarRepository.kt

@@ -355,9 +355,9 @@ class CalendarRepository @Inject constructor(
         calendarId: Int, title: String, start: Instant, end: Instant,
         isAllDay: Boolean, location: String, description: String, color: String?,
         isPrivate: Boolean = false, reminders: List<Int>? = null,
-        rrule: String? = null, birthYear: Int? = null,
+        rrule: String? = null, birthYear: Int? = null, externalUid: String? = null,
     ) = guarded {
-        api.createLocalEvent(eventBody(calendarId, title, start, end, isAllDay, location, description, color, isPrivate, reminders, rrule, birthYear))
+        api.createLocalEvent(eventBody(calendarId, title, start, end, isAllDay, location, description, color, isPrivate, reminders, rrule, birthYear, externalUid))
             .ensureSuccess()
     }
 
@@ -365,8 +365,9 @@ class CalendarRepository @Inject constructor(
         uid: String, title: String, start: Instant, end: Instant,
         isAllDay: Boolean, location: String, description: String, color: String?,
         isPrivate: Boolean = false, reminders: List<Int>? = null,
+        rrule: String? = null, birthYear: Int? = null, externalUid: String? = null,
     ) = guarded {
-        api.updateLocalEvent(uid, eventBody(null, title, start, end, isAllDay, location, description, color, isPrivate, reminders))
+        api.updateLocalEvent(uid, eventBody(null, title, start, end, isAllDay, location, description, color, isPrivate, reminders, rrule, birthYear, externalUid))
             .ensureSuccess()
     }
 
@@ -618,7 +619,7 @@ class CalendarRepository @Inject constructor(
         calendarId: Int?, title: String, start: Instant, end: Instant,
         isAllDay: Boolean, location: String, description: String, color: String?,
         isPrivate: Boolean = false, reminders: List<Int>? = null,
-        rrule: String? = null, birthYear: Int? = null,
+        rrule: String? = null, birthYear: Int? = null, externalUid: String? = null,
     ) = jsonBody(
         buildMap {
             calendarId?.let { put("calendar_id", it) }
@@ -633,6 +634,17 @@ class CalendarRepository @Inject constructor(
             if (reminders != null) put("reminders", org.json.JSONArray(reminders))
             if (!rrule.isNullOrBlank()) put("rrule", rrule)
             if (birthYear != null) put("birth_year", birthYear)
+            if (!externalUid.isNullOrBlank()) put("external_uid", externalUid)
         }
     )
+
+    // ---- Birthdays (Contacts import) ----
+
+    suspend fun getBirthdayEntries(calendarId: Int): List<com.scarriffle.calendarr.domain.model.BirthdayEntry> =
+        guarded { api.getBirthdays(calendarId) }
+
+    suspend fun reportBirthdaySync(deviceId: String, deviceName: String, count: Int) = guarded {
+        api.reportBirthdaySync(jsonBody("device_id" to deviceId, "device_name" to deviceName, "count" to count))
+            .ensureSuccess()
+    }
 }

app/src/main/java/com/scarriffle/calendarr/data/ContactsReader.kt

@@ -0,0 +1,66 @@
+package com.scarriffle.calendarr.data
+
+import android.content.Context
+import android.provider.ContactsContract
+
+/** One birthday read from the address book. */
+data class ContactBirthday(
+    val contactId: String,
+    val name: String,
+    val month: Int,
+    val day: Int,
+    val year: Int?,
+)
+
+/** Reads birthdays from the system Contacts (requires READ_CONTACTS). */
+object ContactsReader {
+
+    fun readBirthdays(context: Context): List<ContactBirthday> {
+        val out = mutableListOf<ContactBirthday>()
+        val projection = arrayOf(
+            ContactsContract.Data.CONTACT_ID,
+            ContactsContract.CommonDataKinds.Event.START_DATE,
+            ContactsContract.Data.DISPLAY_NAME,
+        )
+        val selection = "${ContactsContract.Data.MIMETYPE} = ? AND ${ContactsContract.CommonDataKinds.Event.TYPE} = ?"
+        val args = arrayOf(
+            ContactsContract.CommonDataKinds.Event.CONTENT_ITEM_TYPE,
+            ContactsContract.CommonDataKinds.Event.TYPE_BIRTHDAY.toString(),
+        )
+        context.contentResolver.query(ContactsContract.Data.CONTENT_URI, projection, selection, args, null)
+            ?.use { c ->
+                val idIdx = c.getColumnIndexOrThrow(ContactsContract.Data.CONTACT_ID)
+                val dateIdx = c.getColumnIndexOrThrow(ContactsContract.CommonDataKinds.Event.START_DATE)
+                val nameIdx = c.getColumnIndexOrThrow(ContactsContract.Data.DISPLAY_NAME)
+                while (c.moveToNext()) {
+                    val raw = c.getString(dateIdx) ?: continue
+                    val name = c.getString(nameIdx)?.takeIf { it.isNotBlank() } ?: continue
+                    val id = c.getString(idIdx) ?: continue
+                    val ymd = parseDate(raw) ?: continue
+                    out.add(ContactBirthday(id, name, ymd.second, ymd.third, ymd.first))
+                }
+            }
+        // A contact could carry more than one birthday row — keep the first.
+        return out.distinctBy { it.contactId }
+    }
+
+    /** Returns (year?, month, day). Handles "yyyy-MM-dd", "--MM-dd" (no year),
+     *  and "yyyyMMdd". */
+    private fun parseDate(raw: String): Triple<Int?, Int, Int>? = try {
+        val s = raw.trim()
+        when {
+            s.startsWith("--") -> {
+                val p = s.removePrefix("--").split("-")
+                Triple(null, p[0].toInt(), p[1].toInt())
+            }
+            s.contains("-") -> {
+                val p = s.split("-")
+                if (p.size == 3) Triple(p[0].toIntOrNull()?.takeIf { it > 0 }, p[1].toInt(), p[2].toInt()) else null
+            }
+            s.length == 8 -> Triple(s.substring(0, 4).toInt().takeIf { it > 0 }, s.substring(4, 6).toInt(), s.substring(6, 8).toInt())
+            else -> null
+        }
+    } catch (e: Exception) {
+        null
+    }
+}

app/src/main/java/com/scarriffle/calendarr/data/SettingsStore.kt

@@ -164,6 +164,20 @@ class SettingsStore @Inject constructor(
         get() = prefs.getBoolean(K_HIDE_MENU, false)
         set(value) = prefs.edit().putBoolean(K_HIDE_MENU, value).apply()
 
+    /** Whether this device mirrors its Contacts birthdays into the birthday calendar. */
+    var birthdaysSyncEnabled: Boolean
+        get() = prefs.getBoolean(K_BDAY_ENABLED, false)
+        set(value) = prefs.edit().putBoolean(K_BDAY_ENABLED, value).apply()
+
+    /** Stable per-install id used to scope this device's contact-birthday rows. */
+    val birthdaysDeviceId: String
+        get() {
+            prefs.getString(K_BDAY_DEVICE, null)?.let { return it }
+            val id = java.util.UUID.randomUUID().toString()
+            prefs.edit().putString(K_BDAY_DEVICE, id).apply()
+            return id
+        }
+
     // --- Hidden calendars ("source:id") ---
 
     var hiddenCalendarKeys: Set<String>
@@ -219,6 +233,8 @@ class SettingsStore @Inject constructor(
         const val K_CACHE_MONTHS = "cache_months"
         const val K_MONTH_PAGED = "month_view_paged"
         const val K_HIDE_MENU = "hide_menu_button"
+        const val K_BDAY_ENABLED = "birthdays_sync_enabled"
+        const val K_BDAY_DEVICE = "birthdays_device_id"
         const val K_HIDDEN = "hidden_calendar_keys"
         const val K_BANISHED = "banished_calendar_keys"
         const val K_REMINDER_DISABLED = "reminder_disabled_calendar_keys"

app/src/main/java/com/scarriffle/calendarr/data/remote/CalendarrApi.kt

@@ -222,6 +222,12 @@ interface CalendarrApi {
     @DELETE("api/local/events/{uid}")
     suspend fun deleteLocalEvent(@Path("uid") uid: String): Response<ResponseBody>
 
+    @GET("api/local/calendars/{id}/birthdays")
+    suspend fun getBirthdays(@Path("id") id: Int): List<com.scarriffle.calendarr.domain.model.BirthdayEntry>
+
+    @POST("api/birthdays/sync-report")
+    suspend fun reportBirthdaySync(@Body body: RequestBody): Response<ResponseBody>
+
     @POST("api/caldav/events")
     suspend fun createCalDAVEvent(@Body body: RequestBody): Response<ResponseBody>
 

app/src/main/java/com/scarriffle/calendarr/domain/model/Accounts.kt

@@ -101,6 +101,18 @@ data class UserProfile(
     @Json(name = "directory_hidden") val directoryHidden: Boolean = false,
 )
 
+/** One stored birthday (GET /api/local/calendars/{id}/birthdays). Contact-sourced
+ *  rows carry an external_uid ("contact:<deviceId>:<contactId>"); manual ones null. */
+@JsonClass(generateAdapter = false)
+data class BirthdayEntry(
+    val uid: String,
+    @Json(name = "external_uid") val externalUid: String? = null,
+    val title: String = "",
+    val month: Int? = null,
+    val day: Int? = null,
+    @Json(name = "birth_year") val birthYear: Int? = null,
+)
+
 /** A calendar the user can create events in (resolved from all writable sources). */
 data class WritableCalendar(
     val id: String,

app/src/main/java/com/scarriffle/calendarr/ui/L10n.kt

@@ -158,6 +158,7 @@ object L10n {
             "birthday.new" to "Neuer Geburtstag", "birthday.new_title" to "Neuen Geburtstag hinzufügen",
             "birthday.calendar_name" to "Geburtstage",
             "birthday.activate" to "Geburtstagskalender aktivieren",
+            "birthday.import_contacts" to "Aus Kontakten importieren",
             "birthday.activate_hint" to "Aktiviere den Geburtstagskalender, um Geburtstage anzulegen. Er erscheint als eigener Kalender in der Seitenleiste.",
             "birthday.is_calendar" to "Geburtstagskalender",
             "birthday.person" to "Name", "birthday.person_ph" to "Name der Person",
@@ -337,6 +338,7 @@ object L10n {
             "birthday.new" to "New birthday", "birthday.new_title" to "Add new birthday",
             "birthday.calendar_name" to "Birthdays",
             "birthday.activate" to "Enable birthday calendar",
+            "birthday.import_contacts" to "Import from contacts",
             "birthday.activate_hint" to "Enable the birthday calendar to add birthdays. It appears as its own calendar in the sidebar.",
             "birthday.is_calendar" to "Birthday calendar",
             "birthday.person" to "Name", "birthday.person_ph" to "Person's name",

app/src/main/java/com/scarriffle/calendarr/ui/calendar/BirthdayDialog.kt

@@ -40,6 +40,7 @@ fun BirthdayDialog(
     calendar: LocalCalendar?,
     onDismiss: () -> Unit,
     onActivate: () -> Unit,
+    onImportContacts: () -> Unit,
     onSave: (name: String, date: LocalDate, yearKnown: Boolean) -> Unit,
 ) {
     var name by remember { mutableStateOf("") }
@@ -70,6 +71,8 @@ fun BirthdayDialog(
                         selected = yearUnknown, onClick = { yearUnknown = !yearUnknown },
                         label = { Text(tr("birthday.year_unknown")) },
                     )
+                    Spacer(Modifier.size(4.dp))
+                    TextButton(onClick = onImportContacts) { Text(tr("birthday.import_contacts")) }
                 }
             }
         },

app/src/main/java/com/scarriffle/calendarr/ui/calendar/CalendarScreen.kt

@@ -130,6 +130,30 @@ fun CalendarScreen(
         onDispose { lifecycleOwner.lifecycle.removeObserver(observer) }
     }
 
+    // Contacts birthday import (mirrors iOS): request permission on demand; sync
+    // this device's contact birthdays into the birthday calendar.
+    val deviceName = android.os.Build.MODEL ?: "Android"
+    fun runBirthdayImport() {
+        vm.birthdaysSyncEnabled = true
+        vm.syncContactBirthdays(com.scarriffle.calendarr.data.ContactsReader.readBirthdays(context), deviceName)
+    }
+    val contactsPermLauncher = androidx.activity.compose.rememberLauncherForActivityResult(
+        androidx.activity.result.contract.ActivityResultContracts.RequestPermission()
+    ) { granted -> if (granted) runBirthdayImport() }
+    fun startBirthdayImport() {
+        if (androidx.core.content.ContextCompat.checkSelfPermission(
+                context, android.Manifest.permission.READ_CONTACTS
+            ) == android.content.pm.PackageManager.PERMISSION_GRANTED
+        ) runBirthdayImport() else contactsPermLauncher.launch(android.Manifest.permission.READ_CONTACTS)
+    }
+    androidx.compose.runtime.LaunchedEffect(Unit) {
+        if (vm.birthdaysSyncEnabled &&
+            androidx.core.content.ContextCompat.checkSelfPermission(
+                context, android.Manifest.permission.READ_CONTACTS
+            ) == android.content.pm.PackageManager.PERMISSION_GRANTED
+        ) runBirthdayImport()
+    }
+
     var viewMenuOpen by remember { mutableStateOf(false) }
     var showMenu by remember { mutableStateOf(false) }
     var detailEvent by remember { mutableStateOf<CalEvent?>(null) }
@@ -304,6 +328,7 @@ fun CalendarScreen(
             calendar = birthdayCal,
             onDismiss = { showBirthday = false },
             onActivate = { birthdayScope.launch { birthdayCal = vm.ensureBirthdayCalendar(birthdayCalName) } },
+            onImportContacts = { showBirthday = false; startBirthdayImport() },
             onSave = { name, date, yearKnown ->
                 birthdayCal?.let { vm.createBirthday(it.id, name, date, yearKnown) {} }
                 showBirthday = false

app/src/main/java/com/scarriffle/calendarr/ui/calendar/CalendarViewModel.kt

@@ -145,6 +145,64 @@ class CalendarViewModel @Inject constructor(
     val calendarOrder: List<String> get() = settingsStore.calendarOrder
     fun setCalendarOrder(keys: List<String>) { settingsStore.calendarOrder = keys }
 
+    // ---- Contacts birthday import (mirrors the iOS BirthdaysImporter) ----
+
+    var birthdaysSyncEnabled: Boolean
+        get() = settingsStore.birthdaysSyncEnabled
+        set(value) { settingsStore.birthdaysSyncEnabled = value }
+
+    /** Mirror this device's contact birthdays into the (existing) birthday
+     *  calendar: reconcile rows scoped to this device's external_uid prefix
+     *  (add / update / delete), then report the device. No-op if disabled or
+     *  the birthday calendar hasn't been created. */
+    fun syncContactBirthdays(contacts: List<com.scarriffle.calendarr.data.ContactBirthday>, deviceName: String) {
+        if (!settingsStore.birthdaysSyncEnabled) return
+        viewModelScope.launch {
+            runCatching {
+                val cal = repository.getLocalCalendars().firstOrNull { it.isBirthday && it.owned }
+                    ?: return@runCatching
+                val existing = repository.getBirthdayEntries(cal.id)
+                val deviceId = settingsStore.birthdaysDeviceId
+                val prefix = "contact:$deviceId:"
+                val byExt = existing.filter { it.externalUid?.startsWith(prefix) == true }
+                    .associateBy { it.externalUid!! }
+                val seen = mutableSetOf<String>()
+                for (c in contacts) {
+                    val ext = prefix + c.contactId
+                    seen.add(ext)
+                    val (start, end) = birthdayRange(c.month, c.day, c.year)
+                    val match = byExt[ext]
+                    if (match != null) {
+                        val changed = match.title != c.name || match.month != c.month ||
+                            match.day != c.day || match.birthYear != c.year
+                        if (changed) repository.updateLocalEvent(
+                            uid = match.uid, title = c.name, start = start, end = end,
+                            isAllDay = true, location = "", description = "", color = null,
+                            rrule = "FREQ=YEARLY", birthYear = c.year, externalUid = ext,
+                        )
+                    } else {
+                        repository.createLocalEvent(
+                            calendarId = cal.id, title = c.name, start = start, end = end,
+                            isAllDay = true, location = "", description = "", color = null,
+                            rrule = "FREQ=YEARLY", birthYear = c.year, externalUid = ext,
+                        )
+                    }
+                }
+                byExt.filterKeys { it !in seen }.values.forEach { repository.deleteLocalEvent(it.uid) }
+                repository.reportBirthdaySync(deviceId, deviceName, contacts.size)
+            }
+            loadVisible(force = true)
+        }
+    }
+
+    private fun birthdayRange(month: Int, day: Int, year: Int?): Pair<Instant, Instant> {
+        val anchor = year ?: 2000 // leap-safe anchor for Feb 29 with unknown year
+        val date = LocalDate.of(anchor, month, day)
+        val start = date.atTime(12, 0).atZone(zone).toInstant()
+        val end = date.plusDays(1).atTime(12, 0).atZone(zone).toInstant()
+        return start to end
+    }
+
     /** Default duration (minutes) for a new event's end time. */
     val defaultEventDurationMinutes: Int get() = settingsStore.loadSettings().defaultEventDurationMinutes