implement MPRIS SetVolume

backend/mpris.go

@@ -59,6 +59,11 @@ func NewMPRISHandler(playerName string, p *player.Player, pm *PlaybackManager) *
 			m.evt.Player.OnTitle()
 		}
 	})
+	m.pm.OnVolumeChange(func(vol int) {
+		if m.connErr == nil {
+			m.evt.Player.OnVolume()
+		}
+	})
 	emitPlayStatus := func() {
 		if m.connErr == nil {
 			m.evt.Player.OnPlayPause()
@@ -253,8 +258,8 @@ func (m *MPRISHandler) Volume() (float64, error) {
 	return float64(m.p.GetVolume()) / 100, nil
 }
 
-func (m *MPRISHandler) SetVolume(float64) error {
-	return errNotImplemented
+func (m *MPRISHandler) SetVolume(v float64) error {
+	return m.pm.SetVolume(int(v * 100))
 }
 
 func (m *MPRISHandler) Position() (int64, error) {

backend/playbackmanager.go

@@ -49,6 +49,7 @@ type PlaybackManager struct {
 	onSongChange     []func(nowPlaying, justScrobbledIfAny *mediaprovider.Track)
 	onPlayTimeUpdate []func(float64, float64)
 	onLoopModeChange []func(LoopMode)
+	onVolumeChange   []func(int)
 }
 
 func NewPlaybackManager(
@@ -142,6 +143,11 @@ func (p *PlaybackManager) OnLoopModeChange(cb func(LoopMode)) {
 	p.onLoopModeChange = append(p.onLoopModeChange, cb)
 }
 
+// Registers a callback that is notified whenever the volume changes.
+func (p *PlaybackManager) OnVolumeChange(cb func(int)) {
+	p.onVolumeChange = append(p.onVolumeChange, cb)
+}
+
 // Loads the specified album into the play queue.
 func (p *PlaybackManager) LoadAlbum(albumID string, appendToQueue bool, shuffle bool) error {
 	album, err := p.sm.Server.GetAlbum(albumID)
@@ -335,6 +341,21 @@ func (p *PlaybackManager) LoopMode() LoopMode {
 	return LoopMode(p.player.GetLoopMode())
 }
 
+func (p *PlaybackManager) SetVolume(vol int) error {
+	vol = clamp(vol, 0, 100)
+	if err := p.player.SetVolume(vol); err != nil {
+		return err
+	}
+	for _, cb := range p.onVolumeChange {
+		cb(vol)
+	}
+	return nil
+}
+
+func (p *PlaybackManager) Volume() int {
+	return p.player.GetVolume()
+}
+
 // call BEFORE updating p.nowPlayingIdx
 func (p *PlaybackManager) checkScrobble() {
 	if !p.scrobbleCfg.Enabled || len(p.playQueue) == 0 || p.nowPlayingIdx < 0 {