playlists now save to files, can be restored from files

backend/library/library.go

@@ -63,13 +63,20 @@ type queueClearer interface {
 	Clear()
 }
 
+// playlistRestorer is a narrow interface for restoring playlists
+// from M3U8 files after a library rescan.
+type playlistRestorer interface {
+	RestoreAllPlaylists()
+}
+
 // Library manages scanning and querying the music collection.
 type Library struct {
-	ctx    context.Context
-	logger *slog.Logger
-	conf   *Config
-	db     *database.DB
-	queue  queueClearer
+	ctx              context.Context
+	logger           *slog.Logger
+	conf             *Config
+	db               *database.DB
+	queue            queueClearer
+	playlistRestorer playlistRestorer
 }
 
 // SetQueue provides the library with a reference to the queue so
@@ -79,6 +86,13 @@ func (l *Library) SetQueue(q queueClearer) {
 	l.queue = q
 }
 
+// SetPlaylistRestorer provides the library with a reference to
+// the playlist service so that FullRescan can restore playlists
+// from M3U8 files after wiping data.
+func (l *Library) SetPlaylistRestorer(p playlistRestorer) {
+	l.playlistRestorer = p
+}
+
 // NewLibrary creates a new library with the given configuration.
 // A nil config is permitted; the library will be inert until a valid
 // configuration is supplied via the LibraryConfigChanged event.

backend/library/rescan.go

@@ -68,6 +68,12 @@ func (l *Library) FullRescan() (*ScanMetrics, error) {
 			clearDBDur + clearFilesDur
 	}
 
+	// Restore playlists from M3U8 files now that the library
+	// has been rescanned and audio_files are populated again.
+	if l.playlistRestorer != nil {
+		l.playlistRestorer.RestoreAllPlaylists()
+	}
+
 	return metrics, err
 }