music: use factory pattern in service components

app/src/main/java/org/oxycblt/auxio/AuxioService.kt

@@ -41,13 +41,14 @@ class AuxioService :
     MediaBrowserServiceCompat(), ForegroundListener, MusicServiceFragment.Invalidator {
     @Inject lateinit var playbackFragment: PlaybackServiceFragment
 
-    @Inject lateinit var musicFragment: MusicServiceFragment
+    @Inject lateinit var musicFragmentFactory: MusicServiceFragment.Factory
+    lateinit var musicFragment: MusicServiceFragment
 
     @SuppressLint("WrongConstant")
     override fun onCreate() {
         super.onCreate()
         sessionToken = playbackFragment.attach(this)
-        musicFragment.attach(this, this)
+        musicFragment = musicFragmentFactory.create(this, this, this)
     }
 
     override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {

app/src/main/java/org/oxycblt/auxio/music/service/Indexer.kt

@@ -36,10 +36,9 @@ import org.oxycblt.auxio.playback.state.PlaybackStateManager
 import org.oxycblt.auxio.util.getSystemServiceCompat
 import org.oxycblt.auxio.util.logD
 
-class Indexer
-@Inject
-constructor(
-    @ApplicationContext override val workerContext: Context,
+class Indexer private constructor(
+    override val workerContext: Context,
+    private val foregroundListener: ForegroundListener,
     private val playbackManager: PlaybackStateManager,
     private val musicRepository: MusicRepository,
     private val musicSettings: MusicSettings,
@@ -50,10 +49,21 @@ constructor(
     MusicRepository.IndexingListener,
     MusicRepository.UpdateListener,
     MusicSettings.Listener {
+    class Factory @Inject constructor(
+        private val playbackManager: PlaybackStateManager,
+        private val musicRepository: MusicRepository,
+        private val musicSettings: MusicSettings,
+        private val imageLoader: ImageLoader,
+        private val contentObserver: SystemContentObserver
+    ) {
+        fun create(context: Context, listener: ForegroundListener) =
+            Indexer(context, listener, playbackManager,
+                musicRepository, musicSettings, imageLoader, contentObserver)
+    }
+
     private val indexJob = Job()
     private val indexScope = CoroutineScope(indexJob + Dispatchers.IO)
     private var currentIndexJob: Job? = null
-    private var foregroundListener: ForegroundListener? = null
     private val indexingNotification = IndexingNotification(workerContext)
     private val observingNotification = ObservingNotification(workerContext)
     private val wakeLock =
@@ -62,8 +72,7 @@ constructor(
             .newWakeLock(
                 PowerManager.PARTIAL_WAKE_LOCK, BuildConfig.APPLICATION_ID + ":IndexingComponent")
 
-    fun attach(listener: ForegroundListener) {
-        foregroundListener = listener
+    init {
         musicSettings.registerListener(this)
         musicRepository.addUpdateListener(this)
         musicRepository.addIndexingListener(this)
@@ -77,7 +86,6 @@ constructor(
         musicRepository.addIndexingListener(this)
         musicRepository.addUpdateListener(this)
         musicRepository.removeIndexingListener(this)
-        foregroundListener = null
     }
 
     override fun requestIndex(withCache: Boolean) {
@@ -91,7 +99,7 @@ constructor(
     override val scope = indexScope
 
     override fun onIndexingStateChanged() {
-        foregroundListener?.updateForeground(ForegroundListener.Change.INDEXER)
+        foregroundListener.updateForeground(ForegroundListener.Change.INDEXER)
         val state = musicRepository.indexingState
         if (state is IndexingState.Indexing) {
             wakeLock.acquireSafe()
@@ -132,7 +140,7 @@ constructor(
         // the music loading process ends.
         if (musicRepository.indexingState == null) {
             logD("Not loading, updating idle session")
-            foregroundListener?.updateForeground(ForegroundListener.Change.INDEXER)
+            foregroundListener.updateForeground(ForegroundListener.Change.INDEXER)
         }
     }
 

app/src/main/java/org/oxycblt/auxio/music/service/MusicBrowser.kt

@@ -37,24 +37,31 @@ import org.oxycblt.auxio.music.Playlist
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.search.SearchEngine
 
-class MusicBrowser
-@Inject
-constructor(
-    @ApplicationContext private val context: Context,
+class MusicBrowser private constructor(
+    private val context: Context,
+    private val invalidator: Invalidator,
     private val musicRepository: MusicRepository,
     private val searchEngine: SearchEngine,
     private val listSettings: ListSettings,
     homeGeneratorFactory: HomeGenerator.Factory
 ) : MusicRepository.UpdateListener, HomeGenerator.Invalidator {
+
+    class Factory @Inject constructor(
+    private val musicRepository: MusicRepository,
+    private val searchEngine: SearchEngine,
+    private val listSettings: ListSettings,
+        private val homeGeneratorFactory: HomeGenerator.Factory
+    ) {
+        fun create(context: Context, invalidator: Invalidator): MusicBrowser =
+            MusicBrowser(context, invalidator, musicRepository, searchEngine, listSettings, homeGeneratorFactory)
+    }
     interface Invalidator {
         fun invalidateMusic(ids: Set<String>)
     }
 
     private val homeGenerator = homeGeneratorFactory.create(this)
-    private var invalidator: Invalidator? = null
 
-    fun attach(invalidator: Invalidator) {
-        this.invalidator = invalidator
+    init {
         musicRepository.addUpdateListener(this)
     }
 
@@ -64,7 +71,7 @@ constructor(
 
     override fun invalidateMusic(type: MusicType, instructions: UpdateInstructions) {
         val id = MediaSessionUID.Tab(TabNode.Home(type)).toString()
-        invalidator?.invalidateMusic(setOf(id))
+        invalidator.invalidateMusic(setOf(id))
     }
 
     override fun invalidateTabs() {
@@ -72,7 +79,7 @@ constructor(
             // TODO: Temporary bodge, move the amount parameter to a bundle extra
             val rootId = MediaSessionUID.Tab(TabNode.Root(i)).toString()
             val moreId = MediaSessionUID.Tab(TabNode.More(i)).toString()
-            invalidator?.invalidateMusic(setOf(rootId, moreId))
+            invalidator.invalidateMusic(setOf(rootId, moreId))
         }
     }
 

app/src/main/java/org/oxycblt/auxio/music/service/MusicServiceFragment.kt

@@ -39,35 +39,40 @@ import org.oxycblt.auxio.util.logW
 class MusicServiceFragment
 @Inject
 constructor(
-    @ApplicationContext private val context: Context,
-    private val indexer: Indexer,
-    private val musicBrowser: MusicBrowser,
+    private val context: Context,
+    foregroundListener: ForegroundListener,
+    private val invalidator: Invalidator,
+    indexerFactory: Indexer.Factory,
+    musicBrowserFactory: MusicBrowser.Factory,
     private val musicRepository: MusicRepository
 ) : MusicBrowser.Invalidator {
-    private var invalidator: Invalidator? = null
+    private val indexer = indexerFactory.create(context, foregroundListener)
+    private val musicBrowser = musicBrowserFactory.create(context, this)
     private val dispatchJob = Job()
     private val dispatchScope = CoroutineScope(dispatchJob + Dispatchers.Default)
 
-    interface Invalidator {
-        fun invalidateMusic(mediaId: String)
+    class Factory @Inject constructor(
+        private val indexerFactory: Indexer.Factory,
+        private val musicBrowserFactory: MusicBrowser.Factory,
+        private val musicRepository: MusicRepository
+    ) {
+        fun create(context: Context, foregroundListener: ForegroundListener, invalidator: Invalidator): MusicServiceFragment =
+            MusicServiceFragment(context, foregroundListener, invalidator, indexerFactory, musicBrowserFactory, musicRepository)
     }
 
-    fun attach(foregroundListener: ForegroundListener, invalidator: Invalidator) {
-        this.invalidator = invalidator
-        indexer.attach(foregroundListener)
-        musicBrowser.attach(this)
+    interface Invalidator {
+        fun invalidateMusic(mediaId: String)
     }
 
     fun release() {
         dispatchJob.cancel()
         musicBrowser.release()
         indexer.release()
-        invalidator = null
     }
 
     override fun invalidateMusic(ids: Set<String>) {
         ids.forEach { mediaId ->
-            requireNotNull(invalidator) { "Invalidator not available" }.invalidateMusic(mediaId)
+            invalidator.invalidateMusic(mediaId)
         }
     }