Added reliable media downloader

app/src/main/AndroidManifest.xml

@@ -7,6 +7,7 @@
     <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
     <uses-permission android:name="android.permission.FOREGROUND_SERVICE_MEDIA_PLAYBACK" />
     <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
+    <uses-permission android:name="android.permission.RUN_USER_INITIATED_JOBS" />
 
     <application
         android:name=".FurumiApplication"
@@ -30,6 +31,10 @@
                 <action android:name="android.intent.action.MEDIA_BUTTON" />
             </intent-filter>
         </service>
+        <service
+            android:name=".offline.OfflineDownloadJobService"
+            android:exported="false"
+            android:permission="android.permission.BIND_JOB_SERVICE" />
 
         <receiver android:name="androidx.media3.session.MediaButtonReceiver"
             android:exported="true">

app/src/main/java/cy/hexor/furumi/data/local/OfflineDownloadJobScheduler.kt

@@ -0,0 +1,55 @@
+package cy.hexor.furumi.data.local
+
+import android.app.job.JobInfo
+import android.app.job.JobScheduler
+import android.content.ComponentName
+import android.content.Context
+import android.os.Build
+import cy.hexor.furumi.domain.model.AuthException
+import cy.hexor.furumi.offline.OfflineDownloadJobService
+import dagger.hilt.android.qualifiers.ApplicationContext
+import javax.inject.Inject
+import javax.inject.Singleton
+
+@Singleton
+class OfflineDownloadJobScheduler @Inject constructor(
+    @param:ApplicationContext private val context: Context
+) {
+    private val jobScheduler = context.getSystemService(JobScheduler::class.java)
+
+    fun schedule(estimatedDownloadBytes: Long) {
+        if (jobScheduler.allPendingJobs.any { it.id == OFFLINE_DOWNLOAD_JOB_ID }) return
+
+        val result = jobScheduler.schedule(buildJobInfo(userInitiated = true, estimatedDownloadBytes))
+        if (result == JobScheduler.RESULT_SUCCESS) return
+
+        val fallbackResult = jobScheduler.schedule(buildJobInfo(userInitiated = false, estimatedDownloadBytes))
+        if (fallbackResult != JobScheduler.RESULT_SUCCESS) {
+            throw AuthException("Unable to schedule offline download")
+        }
+    }
+
+    private fun buildJobInfo(userInitiated: Boolean, estimatedDownloadBytes: Long): JobInfo {
+        val builder = JobInfo.Builder(
+            OFFLINE_DOWNLOAD_JOB_ID,
+            ComponentName(context, OfflineDownloadJobService::class.java)
+        )
+            .setRequiredNetworkType(JobInfo.NETWORK_TYPE_ANY)
+            .setRequiresStorageNotLow(true)
+
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P && estimatedDownloadBytes > 0L) {
+            builder.setEstimatedNetworkBytes(estimatedDownloadBytes, 0L)
+        }
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE &&
+            userInitiated &&
+            jobScheduler.canRunUserInitiatedJobs()
+        ) {
+            builder.setUserInitiated(true)
+        }
+        return builder.build()
+    }
+
+    companion object {
+        const val OFFLINE_DOWNLOAD_JOB_ID = 0x4675_0D1
+    }
+}

app/src/main/java/cy/hexor/furumi/data/local/OfflineDownloadQueueStore.kt

@@ -0,0 +1,49 @@
+package cy.hexor.furumi.data.local
+
+import cy.hexor.furumi.domain.model.OfflineDownloadQueueState
+import cy.hexor.furumi.domain.model.TrackCard
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import javax.inject.Inject
+import javax.inject.Singleton
+
+@Singleton
+class OfflineDownloadQueueStore @Inject constructor(
+    private val libraryStore: OfflineLibraryStore
+) {
+    private val _state = MutableStateFlow(libraryStore.offlineDownloadQueueState())
+
+    val state: StateFlow<OfflineDownloadQueueState> = _state.asStateFlow()
+
+    @Synchronized
+    fun enqueueDownloads(tracks: List<TrackCard>): OfflineDownloadQueueState {
+        _state.value = libraryStore.enqueueOfflineDownloadTracks(tracks)
+        return _state.value
+    }
+
+    @Synchronized
+    fun nextPendingDownloadTrack(): TrackCard? {
+        return libraryStore.nextPendingOfflineDownloadTrack()
+    }
+
+    @Synchronized
+    fun markRunning(trackId: Long) {
+        _state.value = libraryStore.markOfflineDownloadRunning(trackId)
+    }
+
+    @Synchronized
+    fun markCompleted(trackId: Long) {
+        _state.value = libraryStore.markOfflineDownloadCompleted(trackId)
+    }
+
+    @Synchronized
+    fun markFailed(trackId: Long, error: String?) {
+        _state.value = libraryStore.markOfflineDownloadFailed(trackId, error)
+    }
+
+    @Synchronized
+    fun refresh() {
+        _state.value = libraryStore.offlineDownloadQueueState()
+    }
+}

app/src/main/java/cy/hexor/furumi/data/local/OfflineLibraryStore.kt

@@ -12,6 +12,7 @@ import cy.hexor.furumi.data.remote.model.OfflineManifestTrackResponse
 import cy.hexor.furumi.domain.model.ArtistCard
 import cy.hexor.furumi.domain.model.ArtistDetail
 import cy.hexor.furumi.domain.model.ArtistPage
+import cy.hexor.furumi.domain.model.OfflineDownloadQueueState
 import cy.hexor.furumi.domain.model.PlaylistCard
 import cy.hexor.furumi.domain.model.PlaylistDetail
 import cy.hexor.furumi.domain.model.ReleaseCard
@@ -510,6 +511,119 @@ class OfflineLibraryStore @Inject constructor(
         }
     }
 
+    fun enqueueOfflineDownloadTracks(tracks: List<TrackCard>): OfflineDownloadQueueState {
+        if (tracks.isEmpty()) return offlineDownloadQueueState()
+        val now = System.currentTimeMillis()
+        dbHelper.writableDatabase.transaction {
+            tracks.distinctBy { it.id }.forEach { track ->
+                upsertTrackLocked(this, track)
+                insertOrUpdate(TABLE_DOWNLOAD_QUEUE, COL_DOWNLOAD_TRACK_ID, track.id, ContentValues().apply {
+                    put(COL_DOWNLOAD_TRACK_ID, track.id)
+                    put(COL_DOWNLOAD_STATUS, STATUS_PENDING)
+                    putNull(COL_DOWNLOAD_ERROR)
+                    put(COL_DOWNLOAD_ENQUEUED_AT, now)
+                    put(COL_DOWNLOAD_UPDATED_AT, now)
+                })
+            }
+        }
+        return offlineDownloadQueueState()
+    }
+
+    fun nextPendingOfflineDownloadTrack(): TrackCard? {
+        val trackIds = dbHelper.readableDatabase.query(
+            TABLE_DOWNLOAD_QUEUE,
+            arrayOf(COL_DOWNLOAD_TRACK_ID),
+            "$COL_DOWNLOAD_STATUS IN (?, ?)",
+            arrayOf(STATUS_PENDING, STATUS_RUNNING),
+            null,
+            null,
+            "$COL_DOWNLOAD_ENQUEUED_AT ASC"
+        ).useCursor { cursor ->
+            buildList {
+                while (cursor.moveToNext()) add(cursor.getLong(COL_DOWNLOAD_TRACK_ID))
+            }
+        }
+
+        for (trackId in trackIds) {
+            getTrack(trackId, preferLocalMedia = false)?.let { return it }
+            markOfflineDownloadCompleted(trackId)
+        }
+        return null
+    }
+
+    fun markOfflineDownloadRunning(trackId: Long): OfflineDownloadQueueState {
+        return updateOfflineDownloadStatus(trackId, STATUS_RUNNING, error = null)
+    }
+
+    fun markOfflineDownloadCompleted(trackId: Long): OfflineDownloadQueueState {
+        dbHelper.writableDatabase.delete(
+            TABLE_DOWNLOAD_QUEUE,
+            "$COL_DOWNLOAD_TRACK_ID = ?",
+            arrayOf(trackId.toString())
+        )
+        return offlineDownloadQueueState()
+    }
+
+    fun markOfflineDownloadFailed(trackId: Long, error: String?): OfflineDownloadQueueState {
+        return updateOfflineDownloadStatus(trackId, STATUS_FAILED, error)
+    }
+
+    fun offlineDownloadQueueState(): OfflineDownloadQueueState {
+        return dbHelper.readableDatabase.query(
+            TABLE_DOWNLOAD_QUEUE,
+            arrayOf(COL_DOWNLOAD_TRACK_ID, COL_DOWNLOAD_STATUS, COL_DOWNLOAD_ERROR),
+            null,
+            null,
+            null,
+            null,
+            "$COL_DOWNLOAD_UPDATED_AT DESC"
+        ).useCursor { cursor ->
+            val activeTrackIds = mutableSetOf<Long>()
+            val failedTrackIds = mutableSetOf<Long>()
+            var lastError: String? = null
+            while (cursor.moveToNext()) {
+                val trackId = cursor.getLong(COL_DOWNLOAD_TRACK_ID)
+                when (cursor.getString(COL_DOWNLOAD_STATUS)) {
+                    STATUS_PENDING,
+                    STATUS_RUNNING -> activeTrackIds.add(trackId)
+                    STATUS_FAILED -> {
+                        failedTrackIds.add(trackId)
+                        if (lastError == null) {
+                            lastError = cursor.getStringOrNull(COL_DOWNLOAD_ERROR)
+                        }
+                    }
+                }
+            }
+            OfflineDownloadQueueState(
+                activeTrackIds = activeTrackIds,
+                failedTrackIds = failedTrackIds,
+                lastError = lastError
+            )
+        }
+    }
+
+    private fun updateOfflineDownloadStatus(
+        trackId: Long,
+        status: String,
+        error: String?
+    ): OfflineDownloadQueueState {
+        dbHelper.writableDatabase.update(
+            TABLE_DOWNLOAD_QUEUE,
+            ContentValues().apply {
+                put(COL_DOWNLOAD_STATUS, status)
+                if (error == null) {
+                    putNull(COL_DOWNLOAD_ERROR)
+                } else {
+                    put(COL_DOWNLOAD_ERROR, error)
+                }
+                put(COL_DOWNLOAD_UPDATED_AT, System.currentTimeMillis())
+            },
+            "$COL_DOWNLOAD_TRACK_ID = ?",
+            arrayOf(trackId.toString())
+        )
+        return offlineDownloadQueueState()
+    }
+
     private fun getAllTracks(preferLocalMedia: Boolean): List<TrackCard> {
         return dbHelper.readableDatabase.query(
             TABLE_TRACKS,
@@ -730,6 +844,7 @@ class OfflineLibraryStore @Inject constructor(
                 )
                 """.trimIndent()
             )
+            createDownloadQueueTable(db)
         }
 
         override fun onUpgrade(db: SQLiteDatabase, oldVersion: Int, newVersion: Int) {
@@ -737,16 +852,35 @@ class OfflineLibraryStore @Inject constructor(
                 db.execSQL("ALTER TABLE $TABLE_TRACKS ADD COLUMN $COL_AUDIO_PINNED INTEGER NOT NULL DEFAULT 0")
                 db.execSQL("CREATE INDEX IF NOT EXISTS idx_offline_tracks_audio_pinned ON $TABLE_TRACKS($COL_AUDIO_PINNED)")
             }
+            if (oldVersion < 3) {
+                createDownloadQueueTable(db)
+            }
+        }
+
+        private fun createDownloadQueueTable(db: SQLiteDatabase) {
+            db.execSQL(
+                """
+                CREATE TABLE IF NOT EXISTS $TABLE_DOWNLOAD_QUEUE (
+                    $COL_DOWNLOAD_TRACK_ID INTEGER PRIMARY KEY,
+                    $COL_DOWNLOAD_STATUS TEXT NOT NULL,
+                    $COL_DOWNLOAD_ERROR TEXT,
+                    $COL_DOWNLOAD_ENQUEUED_AT INTEGER NOT NULL,
+                    $COL_DOWNLOAD_UPDATED_AT INTEGER NOT NULL
+                )
+                """.trimIndent()
+            )
+            db.execSQL("CREATE INDEX IF NOT EXISTS idx_offline_download_status ON $TABLE_DOWNLOAD_QUEUE($COL_DOWNLOAD_STATUS)")
         }
     }
 
     private companion object {
         const val DB_NAME = "furumi_offline.db"
-        const val DB_VERSION = 2
+        const val DB_VERSION = 3
 
         const val TABLE_TRACKS = "offline_tracks"
         const val TABLE_PLAYLISTS = "offline_playlists"
         const val TABLE_LIKES = "offline_likes"
+        const val TABLE_DOWNLOAD_QUEUE = "offline_download_queue"
 
         const val COL_TRACK_ID = "track_id"
         const val COL_TITLE = "title"
@@ -791,9 +925,18 @@ class OfflineLibraryStore @Inject constructor(
 
         const val COL_LIKE_TRACK_ID = "track_id"
 
+        const val COL_DOWNLOAD_TRACK_ID = "track_id"
+        const val COL_DOWNLOAD_STATUS = "status"
+        const val COL_DOWNLOAD_ERROR = "error"
+        const val COL_DOWNLOAD_ENQUEUED_AT = "enqueued_at"
+        const val COL_DOWNLOAD_UPDATED_AT = "updated_at"
+
         const val STATUS_NONE = "none"
         const val STATUS_READY = "ready"
         const val STATUS_STALE = "stale"
+        const val STATUS_PENDING = "pending"
+        const val STATUS_RUNNING = "running"
+        const val STATUS_FAILED = "failed"
     }
 }
 

app/src/main/java/cy/hexor/furumi/data/local/OfflineMediaStore.kt

@@ -52,6 +52,10 @@ class OfflineMediaStore @Inject constructor(
         }
     }
 
+    suspend fun validateManualDownloadSize(tracks: List<TrackCard>) = withContext(Dispatchers.IO) {
+        ensureManualDownloadsCanFit(tracks.distinctBy { it.id })
+    }
+
     private suspend fun cacheTrackMediaBlocking(track: TrackCard, pinAudio: Boolean, requireAudio: Boolean) {
         libraryStore.upsertTracks(listOf(track))
         libraryStore.markTrackAccessed(track.id)

app/src/main/java/cy/hexor/furumi/data/repository/PlayerRepositoryImpl.kt

@@ -2,6 +2,8 @@ package cy.hexor.furumi.data.repository
 
 import cy.hexor.furumi.data.local.AuthSessionStorage
 import cy.hexor.furumi.data.local.ConnectedDeviceStorage
+import cy.hexor.furumi.data.local.OfflineDownloadJobScheduler
+import cy.hexor.furumi.data.local.OfflineDownloadQueueStore
 import cy.hexor.furumi.data.local.OfflineLibraryStore
 import cy.hexor.furumi.data.local.OfflineMediaStore
 import cy.hexor.furumi.data.local.OfflineSettingsStorage
@@ -34,6 +36,7 @@ import cy.hexor.furumi.domain.model.ConnectedDevicesState
 import cy.hexor.furumi.domain.model.ConnectedJamUser
 import cy.hexor.furumi.domain.model.ConnectedPlaybackState
 import cy.hexor.furumi.domain.model.ListeningHistoryPage
+import cy.hexor.furumi.domain.model.OfflineDownloadQueueState
 import cy.hexor.furumi.domain.model.OfflineState
 import cy.hexor.furumi.domain.model.OfflineSyncSummary
 import cy.hexor.furumi.domain.model.PlaylistCard
@@ -53,11 +56,19 @@ class PlayerRepositoryImpl @Inject constructor(
     private val offlineSettingsStorage: OfflineSettingsStorage,
     private val offlineLibraryStore: OfflineLibraryStore,
     private val offlineMediaStore: OfflineMediaStore,
+    private val offlineDownloadQueueStore: OfflineDownloadQueueStore,
+    private val offlineDownloadJobScheduler: OfflineDownloadJobScheduler,
     private val appClientInfo: AppClientInfo,
     private val playerEndpoints: PlayerEndpoints,
     private val errorParser: AuthApiErrorParser
 ) : PlayerRepository {
     override val offlineState: StateFlow<OfflineState> = offlineSettingsStorage.state
+    override val offlineDownloadQueueState: StateFlow<OfflineDownloadQueueState> = offlineDownloadQueueStore.state
+
+    init {
+        offlineMediaStore.publishStorageStats()
+        offlineDownloadQueueStore.refresh()
+    }
 
     override fun setOfflineModeEnabled(enabled: Boolean) {
         offlineSettingsStorage.setOfflineModeEnabled(enabled)
@@ -147,8 +158,10 @@ class PlayerRepositoryImpl @Inject constructor(
 
     override suspend fun downloadTrackForOffline(track: TrackCard): Result<TrackCard> {
         return try {
-            offlineMediaStore.downloadTrackForOffline(track)
-            Result.success(offlineLibraryStore.getTrack(track.id, preferLocalMedia = true) ?: track)
+            offlineMediaStore.validateManualDownloadSize(listOf(track))
+            offlineDownloadQueueStore.enqueueDownloads(listOf(track))
+            offlineDownloadJobScheduler.schedule(estimatedDownloadBytes(listOf(track)))
+            Result.success(track)
         } catch (e: CancellationException) {
             throw e
         } catch (e: Exception) {
@@ -159,10 +172,11 @@ class PlayerRepositoryImpl @Inject constructor(
 
     override suspend fun downloadTracksForOffline(tracks: List<TrackCard>): Result<List<TrackCard>> {
         return try {
-            offlineMediaStore.downloadTracksForOffline(tracks)
-            Result.success(tracks.map { track ->
-                offlineLibraryStore.getTrack(track.id, preferLocalMedia = true) ?: track
-            })
+            val uniqueTracks = tracks.distinctBy { it.id }
+            offlineMediaStore.validateManualDownloadSize(uniqueTracks)
+            offlineDownloadQueueStore.enqueueDownloads(uniqueTracks)
+            offlineDownloadJobScheduler.schedule(estimatedDownloadBytes(uniqueTracks))
+            Result.success(uniqueTracks)
         } catch (e: CancellationException) {
             throw e
         } catch (e: Exception) {
@@ -927,6 +941,16 @@ class PlayerRepositoryImpl @Inject constructor(
         }
     }
 
+    private fun estimatedDownloadBytes(tracks: List<TrackCard>): Long {
+        return tracks.sumOf { track ->
+            if (track.isAudioCached) {
+                0L
+            } else {
+                track.audioSizeBytes ?: 0L
+            }
+        }
+    }
+
     private companion object {
         const val TRACKS_BY_IDS_CHUNK_SIZE = 500
     }

app/src/main/java/cy/hexor/furumi/domain/model/OfflineMode.kt

@@ -28,3 +28,12 @@ data class OfflineSyncSummary(
     val playlistCount: Int,
     val syncedAtMs: Long
 )
+
+data class OfflineDownloadQueueState(
+    val activeTrackIds: Set<Long> = emptySet(),
+    val failedTrackIds: Set<Long> = emptySet(),
+    val lastError: String? = null
+) {
+    val isDownloading: Boolean
+        get() = activeTrackIds.isNotEmpty()
+}

app/src/main/java/cy/hexor/furumi/domain/repository/PlayerRepository.kt

@@ -7,6 +7,7 @@ import cy.hexor.furumi.domain.model.ConnectedDevicesState
 import cy.hexor.furumi.domain.model.ConnectedJamUser
 import cy.hexor.furumi.domain.model.ConnectedPlaybackState
 import cy.hexor.furumi.domain.model.ListeningHistoryPage
+import cy.hexor.furumi.domain.model.OfflineDownloadQueueState
 import cy.hexor.furumi.domain.model.OfflineState
 import cy.hexor.furumi.domain.model.OfflineSyncSummary
 import cy.hexor.furumi.domain.model.PlaylistCard
@@ -18,6 +19,7 @@ import kotlinx.coroutines.flow.StateFlow
 
 interface PlayerRepository {
     val offlineState: StateFlow<OfflineState>
+    val offlineDownloadQueueState: StateFlow<OfflineDownloadQueueState>
 
     suspend fun getArtists(
         page: Int = 1,

app/src/main/java/cy/hexor/furumi/offline/OfflineDownloadJobService.kt

@@ -0,0 +1,145 @@
+package cy.hexor.furumi.offline
+
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.app.PendingIntent
+import android.app.job.JobParameters
+import android.app.job.JobService
+import android.content.Context
+import android.content.Intent
+import android.os.Build
+import androidx.core.app.NotificationCompat
+import cy.hexor.furumi.MainActivity
+import cy.hexor.furumi.data.local.OfflineDownloadQueueStore
+import cy.hexor.furumi.data.local.OfflineMediaStore
+import dagger.hilt.android.AndroidEntryPoint
+import javax.inject.Inject
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.isActive
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+
+@AndroidEntryPoint
+class OfflineDownloadJobService : JobService() {
+    @Inject lateinit var downloadQueueStore: OfflineDownloadQueueStore
+    @Inject lateinit var offlineMediaStore: OfflineMediaStore
+
+    private val serviceScope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
+    private var activeJob: Job? = null
+    @Volatile private var stoppedBySystem = false
+
+    override fun onStartJob(params: JobParameters): Boolean {
+        stoppedBySystem = false
+        publishUserInitiatedJobNotification(params)
+        activeJob?.cancel()
+        activeJob = serviceScope.launch {
+            try {
+                runDownloadQueue()
+                if (!stoppedBySystem) {
+                    jobFinished(params, false)
+                }
+            } catch (_: CancellationException) {
+                if (!stoppedBySystem) {
+                    jobFinished(params, true)
+                }
+            }
+        }
+        return true
+    }
+
+    override fun onStopJob(params: JobParameters): Boolean {
+        stoppedBySystem = true
+        activeJob?.cancel()
+        return true
+    }
+
+    override fun onDestroy() {
+        activeJob?.cancel()
+        serviceScope.cancel()
+        super.onDestroy()
+    }
+
+    private suspend fun runDownloadQueue() = withContext(Dispatchers.IO) {
+        downloadQueueStore.refresh()
+        offlineMediaStore.publishStorageStats()
+
+        while (isActive) {
+            val track = downloadQueueStore.nextPendingDownloadTrack() ?: break
+            downloadQueueStore.markRunning(track.id)
+            try {
+                offlineMediaStore.downloadTrackForOffline(track)
+                downloadQueueStore.markCompleted(track.id)
+            } catch (e: CancellationException) {
+                throw e
+            } catch (e: Exception) {
+                downloadQueueStore.markFailed(track.id, e.message ?: "Unable to download track")
+            }
+            offlineMediaStore.publishStorageStats()
+        }
+
+        offlineMediaStore.publishStorageStats()
+    }
+
+    private fun publishUserInitiatedJobNotification(params: JobParameters) {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.UPSIDE_DOWN_CAKE || !params.isUserInitiatedJob) {
+            return
+        }
+
+        createNotificationChannel()
+        setNotification(
+            params,
+            NOTIFICATION_ID,
+            buildNotification(),
+            JOB_END_NOTIFICATION_POLICY_REMOVE
+        )
+    }
+
+    private fun buildNotification() =
+        NotificationCompat.Builder(this, CHANNEL_ID)
+            .setSmallIcon(android.R.drawable.stat_sys_download)
+            .setContentTitle("Downloading offline music")
+            .setContentText("Saving tracks for offline playback")
+            .setContentIntent(contentIntent())
+            .setCategory(NotificationCompat.CATEGORY_PROGRESS)
+            .setPriority(NotificationCompat.PRIORITY_LOW)
+            .setProgress(0, 0, true)
+            .setOnlyAlertOnce(true)
+            .setSilent(true)
+            .setOngoing(true)
+            .build()
+
+    private fun contentIntent(): PendingIntent =
+        PendingIntent.getActivity(
+            this,
+            0,
+            Intent(this, MainActivity::class.java),
+            PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT
+        )
+
+    private fun createNotificationChannel() {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O) return
+
+        val channel = NotificationChannel(
+            CHANNEL_ID,
+            "Offline downloads",
+            NotificationManager.IMPORTANCE_LOW
+        ).apply {
+            setShowBadge(false)
+            enableVibration(false)
+            enableLights(false)
+            setSound(null, null)
+        }
+        val notificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
+        notificationManager.createNotificationChannel(channel)
+    }
+
+    private companion object {
+        const val NOTIFICATION_ID = 1002
+        const val CHANNEL_ID = "furumi_offline_downloads"
+    }
+}

app/src/main/java/cy/hexor/furumi/ui/player/PlayerViewModel.kt

@@ -116,6 +116,7 @@ class PlayerViewModel @Inject constructor(
     private var searchJob: Job? = null
     private var jamInviteSearchJob: Job? = null
     private var offlineModeRefreshJob: Job? = null
+    private var offlineDownloadRefreshJob: Job? = null
     private val handledConnectedCommandIds = ArrayDeque<String>()
     private val handledConnectedCommandIdSet = mutableSetOf<String>()
     private var wasCurrentDeviceActive = false
@@ -144,6 +145,7 @@ class PlayerViewModel @Inject constructor(
     init {
         loadGlobalArtistsIfNeeded()
         observeOfflineState()
+        observeOfflineDownloadQueue()
         observePlayback()
         loadLikedTrackIds()
         startConnectedDevicesPolling()
@@ -762,7 +764,9 @@ class PlayerViewModel @Inject constructor(
     }
 
     fun downloadTrackForOffline(track: TrackCard) {
-        if (track.isAudioCached || _uiState.value.offlineDownloadingTrackIds.contains(track.id)) {
+        if (_uiState.value.isDownloadedForOffline(track) ||
+            _uiState.value.isDownloadingForOffline(track)
+        ) {
             return
         }
         if (_uiState.value.offlineState.isOfflineActive) {
@@ -770,24 +774,16 @@ class PlayerViewModel @Inject constructor(
             return
         }
 
-        _uiState.value = _uiState.value.copy(
-            offlineDownloadingTrackIds = _uiState.value.offlineDownloadingTrackIds + track.id,
-            offlineDownloadError = null
-        )
         viewModelScope.launch {
             playerRepository.downloadTrackForOffline(track)
-                .onSuccess { downloadedTrack ->
-                    applyDownloadedOfflineTracks(listOf(downloadedTrack))
-                    _messageEvent.tryEmit("Downloaded for offline")
+                .onSuccess {
+                    _messageEvent.tryEmit("Download queued")
                 }
                 .onFailure { error ->
                     val message = error.message ?: "Unable to download track"
                     _uiState.value = _uiState.value.copy(offlineDownloadError = message)
                     _messageEvent.tryEmit(message)
                 }
-            _uiState.value = _uiState.value.copy(
-                offlineDownloadingTrackIds = _uiState.value.offlineDownloadingTrackIds - track.id
-            )
         }
     }
 
@@ -800,32 +796,27 @@ class PlayerViewModel @Inject constructor(
             return
         }
 
-        val tracks = detail.tracks.filter { !it.isAudioCached }
+        val currentState = _uiState.value
+        val tracks = detail.tracks.filter {
+            !currentState.isDownloadedForOffline(it) && !currentState.isDownloadingForOffline(it)
+        }
         if (tracks.isEmpty()) {
             _messageEvent.tryEmit("Playlist is already downloaded")
             return
         }
-        val trackIds = tracks.map { it.id }.toSet()
-        _uiState.value = _uiState.value.copy(
-            offlineDownloadingPlaylistIds = _uiState.value.offlineDownloadingPlaylistIds + playlistId,
-            offlineDownloadingTrackIds = _uiState.value.offlineDownloadingTrackIds + trackIds,
-            offlineDownloadError = null
-        )
         viewModelScope.launch {
             playerRepository.downloadTracksForOffline(tracks)
-                .onSuccess { downloadedTracks ->
-                    applyDownloadedOfflineTracks(downloadedTracks)
-                    _messageEvent.tryEmit("Playlist downloaded for offline")
+                .onSuccess {
+                    _uiState.value = _uiState.value.copy(
+                        offlineDownloadingPlaylistIds = _uiState.value.offlineDownloadingPlaylistIds + playlistId
+                    )
+                    _messageEvent.tryEmit("Playlist download queued")
                 }
                 .onFailure { error ->
                     val message = error.message ?: "Unable to download playlist"
                     _uiState.value = _uiState.value.copy(offlineDownloadError = message)
                     _messageEvent.tryEmit(message)
                 }
-            _uiState.value = _uiState.value.copy(
-                offlineDownloadingPlaylistIds = _uiState.value.offlineDownloadingPlaylistIds - playlistId,
-                offlineDownloadingTrackIds = _uiState.value.offlineDownloadingTrackIds - trackIds
-            )
         }
     }
 
@@ -1135,6 +1126,35 @@ class PlayerViewModel @Inject constructor(
         }
     }
 
+    private fun observeOfflineDownloadQueue() {
+        viewModelScope.launch {
+            var previousActiveTrackIds = playerRepository.offlineDownloadQueueState.value.activeTrackIds
+            playerRepository.offlineDownloadQueueState.collect { queueState ->
+                val completedTrackIds = (previousActiveTrackIds - queueState.activeTrackIds) -
+                    queueState.failedTrackIds
+                val playlistDetail = _uiState.value.playlistDetail
+                val activePlaylistIds = if (playlistDetail != null &&
+                    playlistDetail.tracks.any { it.id in queueState.activeTrackIds }
+                ) {
+                    setOf(playlistDetail.playlist.id)
+                } else {
+                    emptySet()
+                }
+
+                _uiState.value = _uiState.value.copy(
+                    offlineDownloadedTrackIds = _uiState.value.offlineDownloadedTrackIds + completedTrackIds,
+                    offlineDownloadingTrackIds = queueState.activeTrackIds,
+                    offlineDownloadingPlaylistIds = activePlaylistIds,
+                    offlineDownloadError = queueState.lastError
+                )
+                if (completedTrackIds.isNotEmpty()) {
+                    scheduleOfflineDownloadRefresh()
+                }
+                previousActiveTrackIds = queueState.activeTrackIds
+            }
+        }
+    }
+
     private fun startConnectedDevicesPolling() {
         viewModelScope.launch {
             while (true) {
@@ -1649,6 +1669,14 @@ class PlayerViewModel @Inject constructor(
         }
     }
 
+    private fun scheduleOfflineDownloadRefresh() {
+        offlineDownloadRefreshJob?.cancel()
+        offlineDownloadRefreshJob = viewModelScope.launch {
+            delay(350L)
+            refreshAfterOfflineLibraryChange()
+        }
+    }
+
     private fun refreshAfterOfflineLibraryChange() {
         clearModeSensitiveCaches()
         _uiState.value = _uiState.value.copy(
@@ -1666,29 +1694,6 @@ class PlayerViewModel @Inject constructor(
         _uiState.value.selectedRelease?.id?.let(::loadReleaseDetail)
     }
 
-    private fun applyDownloadedOfflineTracks(downloadedTracks: List<TrackCard>) {
-        if (downloadedTracks.isEmpty()) return
-        val replacements = downloadedTracks.associateBy { it.id }
-        artistDetailCache.keys.toList().forEach { key ->
-            artistDetailCache[key] = artistDetailCache.getValue(key).withReplacedTracks(replacements)
-        }
-        releaseDetailCache.keys.toList().forEach { key ->
-            releaseDetailCache[key] = releaseDetailCache.getValue(key).withReplacedTracks(replacements)
-        }
-        playlistDetailCache.keys.toList().forEach { key ->
-            playlistDetailCache[key] = playlistDetailCache.getValue(key).withReplacedTracks(replacements)
-        }
-
-        val state = _uiState.value
-        _uiState.value = state.copy(
-            offlineDownloadedTrackIds = state.offlineDownloadedTrackIds + replacements.keys,
-            searchResults = state.searchResults?.withReplacedTracks(replacements),
-            artistDetail = state.artistDetail?.withReplacedTracks(replacements),
-            releaseDetail = state.releaseDetail?.withReplacedTracks(replacements),
-            playlistDetail = state.playlistDetail?.withReplacedTracks(replacements)
-        )
-    }
-
     private companion object {
         const val ARTIST_PAGE_SIZE = 60
         const val SEARCH_DEBOUNCE_MS = 300L
@@ -1746,29 +1751,6 @@ private fun PlaylistDetail.previewCoverUrls(): List<String> {
     }.take(PLAYLIST_PREVIEW_IMAGE_LIMIT)
 }
 
-private fun ArtistDetail.withReplacedTracks(replacements: Map<Long, TrackCard>): ArtistDetail {
-    return copy(
-        topTracks = topTracks.withReplacedTracks(replacements),
-        featuredTracks = featuredTracks.withReplacedTracks(replacements)
-    )
-}
-
-private fun ReleaseDetail.withReplacedTracks(replacements: Map<Long, TrackCard>): ReleaseDetail {
-    return copy(tracks = tracks.withReplacedTracks(replacements))
-}
-
-private fun PlaylistDetail.withReplacedTracks(replacements: Map<Long, TrackCard>): PlaylistDetail {
-    return copy(tracks = tracks.withReplacedTracks(replacements))
-}
-
-private fun SearchResults.withReplacedTracks(replacements: Map<Long, TrackCard>): SearchResults {
-    return copy(tracks = tracks.withReplacedTracks(replacements))
-}
-
-private fun List<TrackCard>.withReplacedTracks(replacements: Map<Long, TrackCard>): List<TrackCard> {
-    return map { track -> replacements[track.id] ?: track }
-}
-
 private fun SearchResults.withArtistCards(artistCards: Map<Long, ArtistCard>): SearchResults {
     if (artistCards.isEmpty()) return this
     return copy(