music: back playlists with database

Finally persist playlists with a backing database.

app/src/main/java/org/oxycblt/auxio/detail/DetailViewModel.kt

@@ -299,8 +299,13 @@ constructor(
      */
     fun savePlaylistEdit() {
         val playlist = _currentPlaylist.value ?: return
-        val editedPlaylist = (_editedPlaylist.value ?: return).also { _editedPlaylist.value = null }
+        val editedPlaylist = _editedPlaylist.value ?: return
-        musicRepository.rewritePlaylist(playlist, editedPlaylist)
+        viewModelScope.launch {
+            musicRepository.rewritePlaylist(playlist, editedPlaylist)
+            // TODO: The user could probably press some kind of button if they were fast enough.
+            //  Think of a better way to handle this state.
+            _editedPlaylist.value = null
+        }
     }
 
     /**

app/src/main/java/org/oxycblt/auxio/music/MusicRepository.kt

@@ -116,7 +116,7 @@ interface MusicRepository {
      * @param name The name of the new [Playlist].
      * @param songs The songs to populate the new [Playlist] with.
      */
-    fun createPlaylist(name: String, songs: List<Song>)
+    suspend fun createPlaylist(name: String, songs: List<Song>)
 
     /**
      * Rename a [Playlist].
@@ -124,14 +124,14 @@ interface MusicRepository {
      * @param playlist The [Playlist] to rename.
      * @param name The name of the new [Playlist].
      */
-    fun renamePlaylist(playlist: Playlist, name: String)
+    suspend fun renamePlaylist(playlist: Playlist, name: String)
 
     /**
      * Delete a [Playlist].
      *
      * @param playlist The playlist to delete.
      */
-    fun deletePlaylist(playlist: Playlist)
+    suspend fun deletePlaylist(playlist: Playlist)
 
     /**
      * Add the given [Song]s to a [Playlist].
@@ -139,7 +139,7 @@ interface MusicRepository {
      * @param songs The [Song]s to add to the [Playlist].
      * @param playlist The [Playlist] to add to.
      */
-    fun addToPlaylist(songs: List<Song>, playlist: Playlist)
+    suspend fun addToPlaylist(songs: List<Song>, playlist: Playlist)
 
     /**
      * Update the [Song]s of a [Playlist].
@@ -147,7 +147,7 @@ interface MusicRepository {
      * @param playlist The [Playlist] to update.
      * @param songs The new [Song]s to be contained in the [Playlist].
      */
-    fun rewritePlaylist(playlist: Playlist, songs: List<Song>)
+    suspend fun rewritePlaylist(playlist: Playlist, songs: List<Song>)
 
     /**
      * Request that a music loading operation is started by the current [IndexingWorker]. Does
@@ -276,7 +276,7 @@ constructor(
         (deviceLibrary?.run { findSong(uid) ?: findAlbum(uid) ?: findArtist(uid) ?: findGenre(uid) }
             ?: userLibrary?.findPlaylist(uid))
 
-    override fun createPlaylist(name: String, songs: List<Song>) {
+    override suspend fun createPlaylist(name: String, songs: List<Song>) {
         val userLibrary = userLibrary ?: return
         userLibrary.createPlaylist(name, songs)
         for (listener in updateListeners) {
@@ -285,7 +285,7 @@ constructor(
         }
     }
 
-    override fun renamePlaylist(playlist: Playlist, name: String) {
+    override suspend fun renamePlaylist(playlist: Playlist, name: String) {
         val userLibrary = userLibrary ?: return
         userLibrary.renamePlaylist(playlist, name)
         for (listener in updateListeners) {
@@ -294,7 +294,7 @@ constructor(
         }
     }
 
-    override fun deletePlaylist(playlist: Playlist) {
+    override suspend fun deletePlaylist(playlist: Playlist) {
         val userLibrary = userLibrary ?: return
         userLibrary.deletePlaylist(playlist)
         for (listener in updateListeners) {
@@ -303,7 +303,7 @@ constructor(
         }
     }
 
-    override fun addToPlaylist(songs: List<Song>, playlist: Playlist) {
+    override suspend fun addToPlaylist(songs: List<Song>, playlist: Playlist) {
         val userLibrary = userLibrary ?: return
         userLibrary.addToPlaylist(playlist, songs)
         for (listener in updateListeners) {
@@ -312,7 +312,7 @@ constructor(
         }
     }
 
-    override fun rewritePlaylist(playlist: Playlist, songs: List<Song>) {
+    override suspend fun rewritePlaylist(playlist: Playlist, songs: List<Song>) {
         val userLibrary = userLibrary ?: return
         userLibrary.rewritePlaylist(playlist, songs)
         for (listener in updateListeners) {

app/src/main/java/org/oxycblt/auxio/music/MusicViewModel.kt

@@ -19,10 +19,13 @@
 package org.oxycblt.auxio.music
 
 import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
 import javax.inject.Inject
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.launch
 import org.oxycblt.auxio.util.Event
 import org.oxycblt.auxio.util.MutableEvent
 
@@ -110,7 +113,7 @@ constructor(
      */
     fun createPlaylist(name: String? = null, songs: List<Song> = listOf()) {
         if (name != null) {
-            musicRepository.createPlaylist(name, songs)
+            viewModelScope.launch(Dispatchers.IO) { musicRepository.createPlaylist(name, songs) }
         } else {
             _newPlaylistSongs.put(songs)
         }
@@ -124,7 +127,7 @@ constructor(
      */
     fun renamePlaylist(playlist: Playlist, name: String? = null) {
         if (name != null) {
-            musicRepository.renamePlaylist(playlist, name)
+            viewModelScope.launch(Dispatchers.IO) { musicRepository.renamePlaylist(playlist, name) }
         } else {
             _playlistToRename.put(playlist)
         }
@@ -139,7 +142,7 @@ constructor(
      */
     fun deletePlaylist(playlist: Playlist, rude: Boolean = false) {
         if (rude) {
-            musicRepository.deletePlaylist(playlist)
+            viewModelScope.launch(Dispatchers.IO) { musicRepository.deletePlaylist(playlist) }
         } else {
             _playlistToDelete.put(playlist)
         }
@@ -193,7 +196,7 @@ constructor(
      */
     fun addToPlaylist(songs: List<Song>, playlist: Playlist? = null) {
         if (playlist != null) {
-            musicRepository.addToPlaylist(songs, playlist)
+            viewModelScope.launch(Dispatchers.IO) { musicRepository.addToPlaylist(songs, playlist) }
         } else {
             _songsToAdd.put(songs)
         }

app/src/main/java/org/oxycblt/auxio/music/user/RawPlaylist.kt

@@ -21,6 +21,10 @@ package org.oxycblt.auxio.music.user
 import androidx.room.*
 import org.oxycblt.auxio.music.Music
 
+/**
+ * Raw playlist information persisted to [UserMusicDatabase].
+ * @author Alexander Capehart (OxygenCobalt)
+ */
 data class RawPlaylist(
     @Embedded val playlistInfo: PlaylistInfo,
     @Relation(
@@ -30,12 +34,26 @@ data class RawPlaylist(
     val songs: List<PlaylistSong>
 )
 
+/**
+ * UID and name information corresponding to a [RawPlaylist] entry.
+ * @author Alexander Capehart (OxygenCobalt)
+ */
 @Entity data class PlaylistInfo(@PrimaryKey val playlistUid: Music.UID, val name: String)
 
+/**
+ * Song information corresponding to a [RawPlaylist] entry.
+ * @author Alexander Capehart (OxygenCobalt)
+ */
 @Entity data class PlaylistSong(@PrimaryKey val songUid: Music.UID)
 
-@Entity(primaryKeys = ["playlistUid", "songUid"])
+
+/**
+ * Links individual songs to a playlist entry.
+ * @author Alexander Capehart (OxygenCobalt)
+ */
+@Entity
 data class PlaylistSongCrossRef(
+    @PrimaryKey(autoGenerate = true) val id: Long = 0,
     val playlistUid: Music.UID,
-    @ColumnInfo(index = true) val songUid: Music.UID
+    val songUid: Music.UID
 )

app/src/main/java/org/oxycblt/auxio/music/user/UserLibrary.kt

@@ -57,11 +57,12 @@ interface UserLibrary {
         /**
          * Create a new [UserLibrary].
          *
-         * @param deviceLibrary Asynchronously populated [DeviceLibrary] that can be obtained later.
+         * @param deviceLibraryChannel Asynchronously populated [DeviceLibrary] that can be obtained
-         *   This allows database information to be read before the actual instance is constructed.
+         *   later. This allows database information to be read before the actual instance is
+         *   constructed.
          * @return A new [MutableUserLibrary] with the required implementation.
          */
-        suspend fun read(deviceLibrary: Channel<DeviceLibrary>): MutableUserLibrary
+        suspend fun read(deviceLibraryChannel: Channel<DeviceLibrary>): MutableUserLibrary
     }
 }
 
@@ -78,7 +79,7 @@ interface MutableUserLibrary : UserLibrary {
      * @param name The name of the [Playlist].
      * @param songs The songs to place in the [Playlist].
      */
-    fun createPlaylist(name: String, songs: List<Song>)
+    suspend fun createPlaylist(name: String, songs: List<Song>)
 
     /**
      * Rename a [Playlist].
@@ -86,21 +87,21 @@ interface MutableUserLibrary : UserLibrary {
      * @param playlist The [Playlist] to rename.
      * @param name The name of the new [Playlist].
      */
-    fun renamePlaylist(playlist: Playlist, name: String)
+    suspend fun renamePlaylist(playlist: Playlist, name: String)
 
     /**
      * Delete a [Playlist].
      *
      * @param playlist The playlist to delete.
      */
-    fun deletePlaylist(playlist: Playlist)
+    suspend fun deletePlaylist(playlist: Playlist)
 
     /**
      * Add [Song]s to a [Playlist].
      *
      * @param playlist The [Playlist] to add to. Must currently exist.
      */
-    fun addToPlaylist(playlist: Playlist, songs: List<Song>)
+    suspend fun addToPlaylist(playlist: Playlist, songs: List<Song>)
 
     /**
      * Update the [Song]s of a [Playlist].
@@ -108,23 +109,32 @@ interface MutableUserLibrary : UserLibrary {
      * @param playlist The [Playlist] to update.
      * @param songs The new [Song]s to be contained in the [Playlist].
      */
-    fun rewritePlaylist(playlist: Playlist, songs: List<Song>)
+    suspend fun rewritePlaylist(playlist: Playlist, songs: List<Song>)
 }
 
 class UserLibraryFactoryImpl
 @Inject
 constructor(private val playlistDao: PlaylistDao, private val musicSettings: MusicSettings) :
     UserLibrary.Factory {
-    override suspend fun read(deviceLibrary: Channel<DeviceLibrary>): MutableUserLibrary =
+    override suspend fun read(deviceLibraryChannel: Channel<DeviceLibrary>): MutableUserLibrary {
-        UserLibraryImpl(playlistDao, deviceLibrary.receive(), musicSettings)
+        // While were waiting for the library, read our playlists out.
+        val rawPlaylists = playlistDao.readRawPlaylists()
+        val deviceLibrary = deviceLibraryChannel.receive()
+        // Convert the database playlist information to actual usable playlists.
+        val playlistMap = mutableMapOf<Music.UID, PlaylistImpl>()
+        for (rawPlaylist in rawPlaylists) {
+            val playlistImpl = PlaylistImpl.fromRaw(rawPlaylist, deviceLibrary, musicSettings)
+            playlistMap[playlistImpl.uid] = playlistImpl
+        }
+        return UserLibraryImpl(playlistDao, playlistMap, musicSettings)
+    }
 }
 
 private class UserLibraryImpl(
     private val playlistDao: PlaylistDao,
-    private val deviceLibrary: DeviceLibrary,
+    private val playlistMap: MutableMap<Music.UID, PlaylistImpl>,
     private val musicSettings: MusicSettings
 ) : MutableUserLibrary {
-    private val playlistMap = mutableMapOf<Music.UID, PlaylistImpl>()
     override val playlists: List<Playlist>
         get() = playlistMap.values.toList()
 
@@ -132,35 +142,41 @@ private class UserLibraryImpl(
 
     override fun findPlaylist(name: String) = playlistMap.values.find { it.name.raw == name }
 
-    @Synchronized
+    override suspend fun createPlaylist(name: String, songs: List<Song>) {
-    override fun createPlaylist(name: String, songs: List<Song>) {
         val playlistImpl = PlaylistImpl.from(name, songs, musicSettings)
-        playlistMap[playlistImpl.uid] = playlistImpl
+        synchronized(this) { playlistMap[playlistImpl.uid] = playlistImpl }
+        val rawPlaylist =
+            RawPlaylist(
+                PlaylistInfo(playlistImpl.uid, playlistImpl.name.raw),
+                playlistImpl.songs.map { PlaylistSong(it.uid) })
+        playlistDao.insertPlaylist(rawPlaylist)
     }
 
-    @Synchronized
+    override suspend fun renamePlaylist(playlist: Playlist, name: String) {
-    override fun renamePlaylist(playlist: Playlist, name: String) {
         val playlistImpl =
             requireNotNull(playlistMap[playlist.uid]) { "Cannot rename invalid playlist" }
-        playlistMap[playlist.uid] = playlistImpl.edit(name, musicSettings)
+        synchronized(this) { playlistMap[playlist.uid] = playlistImpl.edit(name, musicSettings) }
+        playlistDao.replacePlaylistInfo(PlaylistInfo(playlist.uid, name))
     }
 
-    @Synchronized
+    override suspend fun deletePlaylist(playlist: Playlist) {
-    override fun deletePlaylist(playlist: Playlist) {
+        synchronized(this) {
-        requireNotNull(playlistMap.remove(playlist.uid)) { "Cannot remove invalid playlist" }
+            requireNotNull(playlistMap.remove(playlist.uid)) { "Cannot remove invalid playlist" }
+        }
+        playlistDao.deletePlaylist(playlist.uid)
     }
 
-    @Synchronized
+    override suspend fun addToPlaylist(playlist: Playlist, songs: List<Song>) {
-    override fun addToPlaylist(playlist: Playlist, songs: List<Song>) {
         val playlistImpl =
             requireNotNull(playlistMap[playlist.uid]) { "Cannot add to invalid playlist" }
-        playlistMap[playlist.uid] = playlistImpl.edit { addAll(songs) }
+        synchronized(this) { playlistMap[playlist.uid] = playlistImpl.edit { addAll(songs) } }
+        playlistDao.insertPlaylistSongs(playlist.uid, songs.map { PlaylistSong(it.uid) })
     }
 
-    @Synchronized
+    override suspend fun rewritePlaylist(playlist: Playlist, songs: List<Song>) {
-    override fun rewritePlaylist(playlist: Playlist, songs: List<Song>) {
         val playlistImpl =
             requireNotNull(playlistMap[playlist.uid]) { "Cannot rewrite invalid playlist" }
-        playlistMap[playlist.uid] = playlistImpl.edit(songs)
+        synchronized(this) { playlistMap[playlist.uid] = playlistImpl.edit(songs) }
+        playlistDao.replacePlaylistSongs(playlist.uid, songs.map { PlaylistSong(it.uid) })
     }
 }

app/src/main/java/org/oxycblt/auxio/music/user/UserModule.kt

@@ -30,7 +30,7 @@ import dagger.hilt.components.SingletonComponent
 @Module
 @InstallIn(SingletonComponent::class)
 interface UserModule {
-    @Binds fun userLibaryFactory(factory: UserLibraryFactoryImpl): UserLibrary.Factory
+    @Binds fun userLibraryFactory(factory: UserLibraryFactoryImpl): UserLibrary.Factory
 }
 
 @Module

app/src/main/java/org/oxycblt/auxio/music/user/UserMusicDatabase.kt

@@ -21,16 +21,112 @@ package org.oxycblt.auxio.music.user
 import androidx.room.*
 import org.oxycblt.auxio.music.Music
 
+/**
+ * Allows persistence of all user-created music information.
+ * @author Alexander Capehart (OxygenCobalt)
+ */
 @Database(
     entities = [PlaylistInfo::class, PlaylistSong::class, PlaylistSongCrossRef::class],
-    version = 28,
+    version = 30,
     exportSchema = false)
 @TypeConverters(Music.UID.TypeConverters::class)
 abstract class UserMusicDatabase : RoomDatabase() {
     abstract fun playlistDao(): PlaylistDao
 }
 
+// TODO: Handle playlist defragmentation? I really don't want dead songs to accumulate in this
+//  database.
+
+/**
+ * The DAO for persisted playlist information.
+ * @author Alexander Capehart (OxygenCobalt)
+ */
 @Dao
 interface PlaylistDao {
-    @Transaction @Query("SELECT * FROM PlaylistInfo") fun readRawPlaylists(): List<RawPlaylist>
+    /**
+     * Read out all playlists stored in the database.
+     * @return A list of [RawPlaylist] representing each playlist stored.
+     */
+    @Transaction
+    @Query("SELECT * FROM PlaylistInfo")
+    suspend fun readRawPlaylists(): List<RawPlaylist>
+
+    /**
+     * Create a new playlist.
+     * @param rawPlaylist The [RawPlaylist] to create.
+     */
+    @Transaction
+    suspend fun insertPlaylist(rawPlaylist: RawPlaylist) {
+        insertInfo(rawPlaylist.playlistInfo)
+        insertSongs(rawPlaylist.songs)
+        insertRefs(
+            rawPlaylist.songs.map {
+                PlaylistSongCrossRef(
+                    playlistUid = rawPlaylist.playlistInfo.playlistUid, songUid = it.songUid)
+            })
+    }
+
+    /**
+     * Replace the currently-stored [PlaylistInfo] for a playlist entry.
+     * @param playlistInfo The new [PlaylistInfo] to store.
+     */
+    @Transaction
+    suspend fun replacePlaylistInfo(playlistInfo: PlaylistInfo) {
+        deleteInfo(playlistInfo.playlistUid)
+        insertInfo(playlistInfo)
+    }
+
+    /**
+     * Delete a playlist entry's [PlaylistInfo] and [PlaylistSong].
+     * @param playlistUid The [Music.UID] of the playlist to delete.
+     */
+    @Transaction
+    suspend fun deletePlaylist(playlistUid: Music.UID) {
+        deleteInfo(playlistUid)
+        deleteRefs(playlistUid)
+    }
+
+    /**
+     * Insert new song entries into a playlist.
+     * @param playlistUid The [Music.UID] of the playlist to insert into.
+     * @param songs The [PlaylistSong] representing each song to put into the playlist.
+     */
+    @Transaction
+    suspend fun insertPlaylistSongs(playlistUid: Music.UID, songs: List<PlaylistSong>) {
+        insertSongs(songs)
+        insertRefs(
+            songs.map { PlaylistSongCrossRef(playlistUid = playlistUid, songUid = it.songUid) })
+    }
+
+    /**
+     * Replace the currently-stored [Song]s of the current playlist entry.
+     * @param playlistUid The [Music.UID] of the playlist to update.
+     * @param songs The [PlaylistSong] representing the new list of songs to be placed in the playlist.
+     */
+    @Transaction
+    suspend fun replacePlaylistSongs(playlistUid: Music.UID, songs: List<PlaylistSong>) {
+        deleteRefs(playlistUid)
+        insertSongs(songs)
+        insertRefs(
+            songs.map { PlaylistSongCrossRef(playlistUid = playlistUid, songUid = it.songUid) })
+    }
+
+    /** Internal, do not use. */
+    @Insert(onConflict = OnConflictStrategy.ABORT) suspend fun insertInfo(info: PlaylistInfo)
+
+    /** Internal, do not use. */
+    @Query("DELETE FROM PlaylistInfo where playlistUid = :playlistUid")
+    suspend fun deleteInfo(playlistUid: Music.UID)
+
+    /** Internal, do not use. */
+    @Insert(onConflict = OnConflictStrategy.IGNORE)
+    suspend fun insertSongs(songs: List<PlaylistSong>)
+
+    /** Internal, do not use. */
+    @Insert(onConflict = OnConflictStrategy.ABORT)
+    suspend fun insertRefs(refs: List<PlaylistSongCrossRef>)
+
+    /** Internal, do not use. */
+    @Query("DELETE FROM PlaylistSongCrossRef where playlistUid = :playlistUid")
+    suspend fun deleteRefs(playlistUid: Music.UID)
 }