music: emulate old music loading process

app/src/main/java/org/oxycblt/auxio/home/HomeFragment.kt

@@ -360,13 +360,22 @@ class HomeFragment :
         binding.homeIndexingProgress.visibility = View.VISIBLE
         binding.homeIndexingActions.visibility = View.INVISIBLE
 
-        binding.homeIndexingStatus.setText(R.string.lng_indexing)
+        when (progress) {
-
+            is IndexingProgress.Indeterminate -> {
+                // In a query/initialization state, show a generic loading status.
+                binding.homeIndexingStatus.text = getString(R.string.lng_indexing)
+                binding.homeIndexingProgress.isIndeterminate = true
+            }
+            is IndexingProgress.Songs -> {
                 // Actively loading songs, show the current progress.
+                binding.homeIndexingStatus.text =
+                    getString(R.string.fmt_indexing, progress.loaded, progress.explored)
                 binding.homeIndexingProgress.apply {
                     isIndeterminate = false
                     max = progress.explored
-            this.progress = progress.interpreted
+                    this.progress = progress.loaded
+                }
+            }
         }
     }
 

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

@@ -61,6 +61,18 @@ class IndexingNotification(private val context: Context) :
      * @return true if the notification updated, false otherwise
      */
     fun updateIndexingState(progress: IndexingProgress): Boolean {
+        when (progress) {
+            is IndexingProgress.Indeterminate -> {
+                // Indeterminate state, use a vaguer description and in-determinate progress.
+                // These events are not very frequent, and thus we don't need to safeguard
+                // against rate limiting.
+                L.d("Updating state to $progress")
+                lastUpdateTime = -1
+                setContentText(context.getString(R.string.lng_indexing))
+                setProgress(0, 0, true)
+                return true
+            }
+            is IndexingProgress.Songs -> {
                 // Determinate state, show an active progress meter. Since these updates arrive
                 // highly rapidly, only update every 1.5 seconds to prevent notification rate
                 // limiting.
@@ -71,11 +83,13 @@ class IndexingNotification(private val context: Context) :
                 lastUpdateTime = SystemClock.elapsedRealtime()
                 L.d("Updating state to $progress")
                 setContentText(
-            context.getString(R.string.fmt_indexing, progress.interpreted, progress.explored))
+                    context.getString(R.string.fmt_indexing, progress.loaded, progress.explored))
-        setProgress(progress.explored, progress.interpreted, false)
+                setProgress(progress.loaded, progress.explored, false)
                 return true
             }
         }
+    }
+}
 
 /**
  * A static [ForegroundServiceNotification] that signals to the user that the app is currently

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

@@ -22,7 +22,9 @@ import android.net.Uri
 import javax.inject.Inject
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.buffer
+import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.flowOn
 import org.oxycblt.auxio.music.stack.explore.Explorer
 import org.oxycblt.auxio.music.stack.interpret.Interpretation
@@ -42,7 +44,11 @@ interface Indexer {
  *
  * @author Alexander Capehart (OxygenCobalt)
  */
-data class IndexingProgress(val interpreted: Int, val explored: Int)
+sealed interface IndexingProgress {
+    data class Songs(val loaded: Int, val explored: Int) : IndexingProgress
+
+    data object Indeterminate : IndexingProgress
+}
 
 class IndexerImpl
 @Inject
@@ -52,20 +58,25 @@ constructor(private val explorer: Explorer, private val interpreter: Interpreter
         interpretation: Interpretation,
         onProgress: suspend (IndexingProgress) -> Unit
     ) = coroutineScope {
-        var interpreted = 0
+        val files = explorer.explore(uris, onProgress)
-        var explored = 0
+        val audioFiles =
-        onProgress(IndexingProgress(interpreted, explored))
+            files.audios
-        val files =
+                .cap(
-            explorer.explore(uris) {
+                    start = { onProgress(IndexingProgress.Songs(0, 0)) },
-                explored++
+                    end = { onProgress(IndexingProgress.Indeterminate) })
-                onProgress(IndexingProgress(interpreted, explored))
+                .flowOn(Dispatchers.IO)
-            }
+                .buffer()
-        val audioFiles = files.audios.flowOn(Dispatchers.IO).buffer()
         val playlistFiles = files.playlists.flowOn(Dispatchers.IO).buffer()
+        interpreter.interpret(audioFiles, playlistFiles, interpretation)
+    }
 
-        interpreter.interpret(audioFiles, playlistFiles, interpretation) {
+    private fun <T> Flow<T>.cap(start: suspend () -> Unit, end: suspend () -> Unit): Flow<T> =
-            interpreted++
+        flow {
-            onProgress(IndexingProgress(interpreted, explored))
+            start()
+            try {
+                collect { emit(it) }
+            } finally {
+                end()
             }
         }
 }

app/src/main/java/org/oxycblt/auxio/music/stack/explore/Explorer.kt

@@ -34,13 +34,14 @@ import kotlinx.coroutines.flow.merge
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.flow.receiveAsFlow
 import kotlinx.coroutines.flow.withIndex
+import org.oxycblt.auxio.music.stack.IndexingProgress
 import org.oxycblt.auxio.music.stack.explore.cache.TagCache
 import org.oxycblt.auxio.music.stack.explore.extractor.TagExtractor
 import org.oxycblt.auxio.music.stack.explore.fs.DeviceFiles
 import org.oxycblt.auxio.music.stack.explore.playlists.StoredPlaylists
 
 interface Explorer {
-    fun explore(uris: List<Uri>, onExplored: suspend () -> Unit): Files
+    fun explore(uris: List<Uri>, onProgress: suspend (IndexingProgress.Songs) -> Unit): Files
 }
 
 data class Files(val audios: Flow<AudioFile>, val playlists: Flow<PlaylistFile>)
@@ -54,14 +55,18 @@ constructor(
     private val storedPlaylists: StoredPlaylists
 ) : Explorer {
     @OptIn(ExperimentalCoroutinesApi::class)
-    override fun explore(uris: List<Uri>, onExplored: suspend () -> Unit): Files {
+    override fun explore(
-        var discovered = 0
+        uris: List<Uri>,
+        onProgress: suspend (IndexingProgress.Songs) -> Unit
+    ): Files {
+        var loaded = 0
+        var explored = 0
         val deviceFiles =
             deviceFiles
                 .explore(uris.asFlow())
                 .onEach {
-                    discovered++
+                    explored++
-                    onExplored()
+                    onProgress(IndexingProgress.Songs(loaded, explored))
                 }
                 .flowOn(Dispatchers.IO)
                 .buffer()
@@ -73,8 +78,13 @@ constructor(
         //        val writtenAudioFiles =
         // tagCache.write(extractedAudioFiles).flowOn(Dispatchers.IO).buffer()
         //        val audioFiles = merge(cachedAudioFiles, writtenAudioFiles)
+        val audioFiles =
+            extractedAudioFiles.onEach {
+                loaded++
+                onProgress(IndexingProgress.Songs(loaded, explored))
+            }
         val playlistFiles = storedPlaylists.read()
-        return Files(extractedAudioFiles, playlistFiles)
+        return Files(audioFiles, playlistFiles)
     }
 
     /** Temporarily split a flow into 8 parallel threads and then */

app/src/main/java/org/oxycblt/auxio/music/stack/explore/fs/DeviceFiles.kt

@@ -32,6 +32,7 @@ import kotlinx.coroutines.flow.flatMapMerge
 import kotlinx.coroutines.flow.flattenMerge
 import kotlinx.coroutines.flow.flow
 import org.oxycblt.auxio.music.stack.explore.DeviceFile
+import timber.log.Timber
 
 interface DeviceFiles {
     fun explore(uris: Flow<Uri>): Flow<DeviceFile>

app/src/main/java/org/oxycblt/auxio/music/stack/interpret/Interpreter.kt

@@ -25,7 +25,6 @@ import kotlinx.coroutines.flow.asFlow
 import kotlinx.coroutines.flow.buffer
 import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.map
-import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.flow.toList
 import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.stack.explore.AudioFile
@@ -49,8 +48,7 @@ interface Interpreter {
     suspend fun interpret(
         audioFiles: Flow<AudioFile>,
         playlistFiles: Flow<PlaylistFile>,
-        interpretation: Interpretation,
+        interpretation: Interpretation
-        onInterpret: suspend () -> Unit
     ): MutableLibrary
 }
 
@@ -58,8 +56,7 @@ class InterpreterImpl @Inject constructor(private val preparer: Preparer) : Inte
     override suspend fun interpret(
         audioFiles: Flow<AudioFile>,
         playlistFiles: Flow<PlaylistFile>,
-        interpretation: Interpretation,
+        interpretation: Interpretation
-        onInterpret: suspend () -> Unit
     ): MutableLibrary {
         val preSongs =
             preparer.prepare(audioFiles, interpretation).flowOn(Dispatchers.Main).buffer()
@@ -69,11 +66,7 @@ class InterpreterImpl @Inject constructor(private val preparer: Preparer) : Inte
 
         val artistLinker = ArtistLinker()
         val artistLinkedSongs =
-            artistLinker
+            artistLinker.register(genreLinkedSongs).flowOn(Dispatchers.Main).toList()
-                .register(genreLinkedSongs)
-                .onEach { onInterpret() }
-                .flowOn(Dispatchers.Main)
-                .toList()
         // This is intentional. Song and album instances are dependent on artist
         // data, so we need to ensure that all of the linked artist data is resolved
         // before we go any further.