ui: add service/notification abstractions

Add additional abstractions for service foreground states and their
notifications.

app/src/main/java/org/oxycblt/auxio/music/system/IndexerNotifications.kt

@@ -17,34 +17,20 @@
  
 package org.oxycblt.auxio.music.system
 
-import android.app.NotificationChannel
 import android.app.NotificationManager
 import android.content.Context
-import android.os.Build
 import androidx.core.app.NotificationCompat
 import org.oxycblt.auxio.BuildConfig
 import org.oxycblt.auxio.IntegerTable
 import org.oxycblt.auxio.R
-import org.oxycblt.auxio.util.getSystemServiceSafe
+import org.oxycblt.auxio.ui.system.ServiceNotification
 import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.util.newMainPendingIntent
 
 /** The notification responsible for showing the indexer state. */
 class IndexingNotification(private val context: Context) :
-    NotificationCompat.Builder(context, CHANNEL_ID) {
+    ServiceNotification(context, INDEXER_CHANNEL) {
-    private val notificationManager = context.getSystemServiceSafe(NotificationManager::class)
-
     init {
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
-            val channel =
-                NotificationChannel(
-                    CHANNEL_ID,
-                    context.getString(R.string.info_indexer_channel_name),
-                    NotificationManager.IMPORTANCE_LOW)
-
-            notificationManager.createNotificationChannel(channel)
-        }
-
         setSmallIcon(R.drawable.ic_indexer_24)
         setCategory(NotificationCompat.CATEGORY_PROGRESS)
         setShowWhen(false)
@@ -56,9 +42,8 @@ class IndexingNotification(private val context: Context) :
         setProgress(0, 0, true)
     }
 
-    fun renotify() {
+    override val code: Int
-        notificationManager.notify(IntegerTable.INDEXER_NOTIFICATION_CODE, build())
+        get() = IntegerTable.INDEXER_NOTIFICATION_CODE
-    }
 
     fun updateIndexingState(indexing: Indexer.Indexing): Boolean {
         when (indexing) {
@@ -82,27 +67,11 @@ class IndexingNotification(private val context: Context) :
 
         return false
     }
-
-    companion object {
-        const val CHANNEL_ID = BuildConfig.APPLICATION_ID + ".channel.INDEXER"
-    }
 }
 
 /** The notification responsible for showing the indexer state. */
-class ObservingNotification(context: Context) : NotificationCompat.Builder(context, CHANNEL_ID) {
+class ObservingNotification(context: Context) : ServiceNotification(context, INDEXER_CHANNEL) {
-    private val notificationManager = context.getSystemServiceSafe(NotificationManager::class)
-
     init {
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
-            val channel =
-                NotificationChannel(
-                    CHANNEL_ID,
-                    context.getString(R.string.info_indexer_channel_name),
-                    NotificationManager.IMPORTANCE_LOW)
-
-            notificationManager.createNotificationChannel(channel)
-        }
-
         setSmallIcon(R.drawable.ic_indexer_24)
         setCategory(NotificationCompat.CATEGORY_SERVICE)
         setShowWhen(false)
@@ -113,11 +82,12 @@ class ObservingNotification(context: Context) : NotificationCompat.Builder(conte
         setContentText(context.getString(R.string.lbl_observing_desc))
     }
 
-    fun renotify() {
+    override val code: Int
-        notificationManager.notify(IntegerTable.INDEXER_NOTIFICATION_CODE, build())
+        get() = IntegerTable.INDEXER_NOTIFICATION_CODE
 }
 
-    companion object {
+private val INDEXER_CHANNEL =
-        const val CHANNEL_ID = BuildConfig.APPLICATION_ID + ".channel.INDEXER"
+    ServiceNotification.ChannelInfo(
-    }
+        id = BuildConfig.APPLICATION_ID + ".channel.INDEXER",
-}
+        R.string.info_indexer_channel_name,
+        NotificationManager.IMPORTANCE_LOW)

app/src/main/java/org/oxycblt/auxio/music/system/IndexerService.kt

@@ -17,7 +17,6 @@
  
 package org.oxycblt.auxio.music.system
 
-import android.app.Notification
 import android.app.Service
 import android.content.Intent
 import android.database.ContentObserver
@@ -25,17 +24,16 @@ import android.os.Handler
 import android.os.IBinder
 import android.os.Looper
 import android.provider.MediaStore
-import androidx.core.app.ServiceCompat
 import coil.imageLoader
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.launch
-import org.oxycblt.auxio.IntegerTable
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.playback.state.PlaybackStateManager
 import org.oxycblt.auxio.settings.Settings
+import org.oxycblt.auxio.ui.system.ForegroundManager
 import org.oxycblt.auxio.util.contentResolverSafe
 import org.oxycblt.auxio.util.logD
 
@@ -49,8 +47,6 @@ import org.oxycblt.auxio.util.logD
  * boilerplate you skip is not worth the insanity of androidx.
  *
  * @author OxygenCobalt
- *
- * TODO: Add abstractions for services. notifications, and generations
  */
 class IndexerService : Service(), Indexer.Controller, Settings.Callback {
     private val indexer = Indexer.getInstance()
@@ -63,19 +59,20 @@ class IndexerService : Service(), Indexer.Controller, Settings.Callback {
     private val playbackManager = PlaybackStateManager.getInstance()
     private lateinit var settings: Settings
 
-    private var isForeground = false
+    private lateinit var foregroundManager: ForegroundManager
     private lateinit var indexingNotification: IndexingNotification
     private lateinit var observingNotification: ObservingNotification
 
     override fun onCreate() {
         super.onCreate()
 
-        settings = Settings(this, this)
+        foregroundManager = ForegroundManager(this)
-        indexerContentObserver = SystemContentObserver()
-
         indexingNotification = IndexingNotification(this)
         observingNotification = ObservingNotification(this)
 
+        settings = Settings(this, this)
+        indexerContentObserver = SystemContentObserver()
+
         indexer.registerController(this)
         if (musicStore.library == null && indexer.isIndeterminate) {
             logD("No library present and no previous response, indexing music now")
@@ -92,6 +89,8 @@ class IndexerService : Service(), Indexer.Controller, Settings.Callback {
     override fun onDestroy() {
         super.onDestroy()
 
+        foregroundManager.release()
+
         // De-initialize the components first to prevent stray reloading events
         settings.release()
         indexerContentObserver.release()
@@ -162,9 +161,9 @@ class IndexerService : Service(), Indexer.Controller, Settings.Callback {
         // notification when initially starting, we will not update the notification
         // unless it indicates that we have changed it.
         val changed = indexingNotification.updateIndexingState(state)
-        if (!tryStartForeground(indexingNotification.build()) && changed) {
+        if (!foregroundManager.tryStartForeground(indexingNotification) && changed) {
             logD("Notification changed, re-posting notification")
-            indexingNotification.renotify()
+            indexingNotification.post()
         }
     }
 
@@ -176,34 +175,14 @@ class IndexerService : Service(), Indexer.Controller, Settings.Callback {
             // we can go foreground later.
             // 2. If a non-foreground service is killed, the app will probably still be alive,
             // and thus the music library will not be updated at all.
-            if (!tryStartForeground(observingNotification.build())) {
+            if (!foregroundManager.tryStartForeground(observingNotification)) {
-                observingNotification.renotify()
+                observingNotification.post()
             }
         } else {
-            tryStopForeground()
+            foregroundManager.tryStopForeground()
         }
     }
 
-    private fun tryStartForeground(notification: Notification): Boolean {
-        if (isForeground) {
-            return false
-        }
-
-        startForeground(IntegerTable.INDEXER_NOTIFICATION_CODE, notification)
-        isForeground = true
-
-        return true
-    }
-
-    private fun tryStopForeground() {
-        if (!isForeground) {
-            return
-        }
-
-        ServiceCompat.stopForeground(this, ServiceCompat.STOP_FOREGROUND_REMOVE)
-        isForeground = false
-    }
-
     // --- SETTING CALLBACKS ---
 
     override fun onSettingChanged(key: String) {

app/src/main/java/org/oxycblt/auxio/playback/state/PlaybackStateManager.kt

@@ -423,9 +423,11 @@ class PlaybackStateManager private constructor() {
         isPlaying = false
         notifyNewPlayback()
 
+        if (index > -1) {
             // Controller may have reloaded the media item, re-seek to the previous position
             seekTo(oldPosition)
         }
+    }
 
     private fun makeStateImpl() =
         PlaybackStateDatabase.SavedState(

app/src/main/java/org/oxycblt/auxio/playback/system/MediaSessionComponent.kt

@@ -43,6 +43,9 @@ import org.oxycblt.auxio.util.logD
  * using something like MediaSessionConnector is more or less impossible.
  *
  * @author OxygenCobalt
+ *
+ * TODO: Update textual metadata first, then cover metadata later. Janky, yes, but also resolves
+ *  some coherency issues.
  */
 class MediaSessionComponent(
     private val context: Context,
@@ -54,12 +57,13 @@ class MediaSessionComponent(
     PlaybackStateManager.Callback,
     Settings.Callback {
     interface Callback {
-        fun onPostNotification(notification: NotificationComponent)
+        fun onPostNotification(notification: NotificationComponent?)
     }
 
+    val mediaSession = MediaSessionCompat(context, context.packageName).apply { isActive = true }
+
     private val playbackManager = PlaybackStateManager.getInstance()
     private val settings = Settings(context, this)
-    val mediaSession = MediaSessionCompat(context, context.packageName).apply { isActive = true }
     private val notification = NotificationComponent(context, mediaSession.sessionToken)
     private val provider = BitmapProvider(context)
 
@@ -98,6 +102,7 @@ class MediaSessionComponent(
     private fun updateMediaMetadata(song: Song?, parent: MusicParent?) {
         if (song == null) {
             mediaSession.setMetadata(emptyMetadata)
+            callback.onPostNotification(null)
             return
         }
 

app/src/main/java/org/oxycblt/auxio/playback/system/NotificationComponent.kt

@@ -18,7 +18,6 @@
 package org.oxycblt.auxio.playback.system
 
 import android.annotation.SuppressLint
-import android.app.NotificationChannel
 import android.app.NotificationManager
 import android.content.Context
 import android.os.Build
@@ -31,7 +30,7 @@ import org.oxycblt.auxio.BuildConfig
 import org.oxycblt.auxio.IntegerTable
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.playback.state.RepeatMode
-import org.oxycblt.auxio.util.getSystemServiceSafe
+import org.oxycblt.auxio.ui.system.ServiceNotification
 import org.oxycblt.auxio.util.newBroadcastPendingIntent
 import org.oxycblt.auxio.util.newMainPendingIntent
 
@@ -43,20 +42,8 @@ import org.oxycblt.auxio.util.newMainPendingIntent
  */
 @SuppressLint("RestrictedApi")
 class NotificationComponent(private val context: Context, sessionToken: MediaSessionCompat.Token) :
-    NotificationCompat.Builder(context, CHANNEL_ID) {
+    ServiceNotification(context, CHANNEL_INFO) {
-    private val notificationManager = context.getSystemServiceSafe(NotificationManager::class)
-
     init {
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
-            val channel =
-                NotificationChannel(
-                    CHANNEL_ID,
-                    context.getString(R.string.info_playback_channel_name),
-                    NotificationManager.IMPORTANCE_DEFAULT)
-
-            notificationManager.createNotificationChannel(channel)
-        }
-
         setSmallIcon(R.drawable.ic_auxio_24)
         setCategory(NotificationCompat.CATEGORY_TRANSPORT)
         setShowWhen(false)
@@ -75,9 +62,8 @@ class NotificationComponent(private val context: Context, sessionToken: MediaSes
         setStyle(MediaStyle().setMediaSession(sessionToken).setShowActionsInCompactView(1, 2, 3))
     }
 
-    fun renotify() {
+    override val code: Int
-        notificationManager.notify(IntegerTable.PLAYBACK_NOTIFICATION_CODE, build())
+        get() = IntegerTable.PLAYBACK_NOTIFICATION_CODE
-    }
 
     // --- STATE FUNCTIONS ---
 
@@ -164,6 +150,10 @@ class NotificationComponent(private val context: Context, sessionToken: MediaSes
     }
 
     companion object {
-        const val CHANNEL_ID = BuildConfig.APPLICATION_ID + ".channel.PLAYBACK"
+        val CHANNEL_INFO =
+            ChannelInfo(
+                id = BuildConfig.APPLICATION_ID + ".channel.PLAYBACK",
+                nameRes = R.string.info_playback_channel_name,
+                importance = NotificationManager.IMPORTANCE_LOW)
     }
 }

app/src/main/java/org/oxycblt/auxio/playback/system/PlaybackService.kt

@@ -24,7 +24,6 @@ import android.content.Intent
 import android.content.IntentFilter
 import android.media.AudioManager
 import android.os.IBinder
-import androidx.core.app.ServiceCompat
 import com.google.android.exoplayer2.C
 import com.google.android.exoplayer2.ExoPlayer
 import com.google.android.exoplayer2.MediaItem
@@ -45,7 +44,6 @@ import kotlinx.coroutines.Job
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
 import org.oxycblt.auxio.BuildConfig
-import org.oxycblt.auxio.IntegerTable
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.playback.replaygain.ReplayGainAudioProcessor
@@ -53,6 +51,7 @@ import org.oxycblt.auxio.playback.state.PlaybackStateDatabase
 import org.oxycblt.auxio.playback.state.PlaybackStateManager
 import org.oxycblt.auxio.playback.state.RepeatMode
 import org.oxycblt.auxio.settings.Settings
+import org.oxycblt.auxio.ui.system.ForegroundManager
 import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.widgets.WidgetComponent
 import org.oxycblt.auxio.widgets.WidgetProvider
@@ -93,7 +92,7 @@ class PlaybackService :
     private lateinit var settings: Settings
 
     // State
-    private var isForeground = false
+    private lateinit var foregroundManager: ForegroundManager
     private var hasPlayed = false
 
     // Coroutines
@@ -106,6 +105,8 @@ class PlaybackService :
     override fun onCreate() {
         super.onCreate()
 
+        foregroundManager = ForegroundManager(this)
+
         // --- PLAYER SETUP ---
 
         replayGainProcessor = ReplayGainAudioProcessor(this)
@@ -163,8 +164,7 @@ class PlaybackService :
     override fun onDestroy() {
         super.onDestroy()
 
-        ServiceCompat.stopForeground(this, ServiceCompat.STOP_FOREGROUND_REMOVE)
+        foregroundManager.release()
-        isForeground = false
 
         // Pause just in case this destruction was unexpected.
         playbackManager.isPlaying = false
@@ -272,14 +272,17 @@ class PlaybackService :
         player.playWhenReady = isPlaying
     }
 
-    override fun onPostNotification(notification: NotificationComponent) {
+    override fun onPostNotification(notification: NotificationComponent?) {
-        if (hasPlayed && playbackManager.song != null) {
+        if (notification == null) {
-            if (!isForeground) {
+            // This case is only here if I ever need to move foreground stopping from
-                startForeground(IntegerTable.PLAYBACK_NOTIFICATION_CODE, notification.build())
+            // the player code to the notification code.
-                isForeground = true
+            logD("No notification, ignoring")
-            } else {
+            return
-                // If we are already in foreground just update the notification
+        }
-                notification.renotify()
+
+        if (hasPlayed) {
+            if (!foregroundManager.tryStartForeground(notification)) {
+                notification.post()
             }
         }
     }
@@ -329,12 +332,13 @@ class PlaybackService :
 
     /** Stop the foreground state and hide the notification */
     private fun stopAndSave() {
-        ServiceCompat.stopForeground(this, ServiceCompat.STOP_FOREGROUND_REMOVE)
+        if (foregroundManager.tryStopForeground()) {
-        isForeground = false
+            logD("Saving playback state")
             saveScope.launch {
                 playbackManager.saveState(PlaybackStateDatabase.getInstance(this@PlaybackService))
             }
         }
+    }
 
     /** A [BroadcastReceiver] for receiving general playback events from the system. */
     private inner class PlaybackReceiver : BroadcastReceiver() {

app/src/main/java/org/oxycblt/auxio/ui/system/ForegroundManager.kt

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2022 Auxio Project
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+ 
+package org.oxycblt.auxio.ui.system
+
+import android.app.Service
+import androidx.core.app.ServiceCompat
+import org.oxycblt.auxio.util.logD
+
+/**
+ * Wrapper to create consistent behavior regarding a service's foreground state.
+ * @author OxygenCobalt
+ */
+class ForegroundManager(private val service: Service) {
+    private var isForeground = false
+
+    fun release() {
+        tryStopForeground()
+    }
+
+    /**
+     * Try to enter a foreground state. Returns false if already in foreground, returns true
+     * if state was entered.
+     */
+    fun tryStartForeground(notification: ServiceNotification): Boolean {
+        if (isForeground) {
+            return false
+        }
+
+        logD("Starting foreground state")
+
+        service.startForeground(notification.code, notification.build())
+        isForeground = true
+
+        return true
+    }
+
+    /**
+     * Try to stop a foreground state. Returns false if already in backend, returns true
+     * if state was stopped.
+     */
+    fun tryStopForeground(): Boolean {
+        if (!isForeground) {
+            return false
+        }
+
+        logD("Stopping foreground state")
+
+        ServiceCompat.stopForeground(service, ServiceCompat.STOP_FOREGROUND_REMOVE)
+        isForeground = false
+
+        return true
+    }
+}

app/src/main/java/org/oxycblt/auxio/ui/system/ServiceNotification.kt

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2022 Auxio Project
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+ 
+package org.oxycblt.auxio.ui.system
+
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.content.Context
+import android.os.Build
+import androidx.annotation.StringRes
+import androidx.core.app.NotificationCompat
+import org.oxycblt.auxio.util.getSystemServiceSafe
+
+/**
+ * Wrapper around [NotificationCompat.Builder] that automates parts of the notification setup.
+ * @author OxygenCobalt
+ */
+abstract class ServiceNotification(context: Context, info: ChannelInfo) :
+    NotificationCompat.Builder(context, info.id) {
+    private val notificationManager = context.getSystemServiceSafe(NotificationManager::class)
+
+    init {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+
+            val channel =
+                NotificationChannel(info.id, context.getString(info.nameRes), info.importance)
+
+            notificationManager.createNotificationChannel(channel)
+        }
+    }
+
+    abstract val code: Int
+
+    fun post() {
+        notificationManager.notify(code, build())
+    }
+
+    data class ChannelInfo(val id: String, @StringRes val nameRes: Int, val importance: Int)
+}