WIP: feat: add "Play next" MenuItem

backend/app.go

@@ -324,7 +324,7 @@ func (a *App) LoadSavedPlayQueue() error {
 		return nil
 	}
 
-	if err := a.PlaybackManager.LoadTracks(queue.Tracks, false, false); err != nil {
+	if err := a.PlaybackManager.LoadTracks(queue.Tracks, Replace, false); err != nil {
 		return err
 	}
 	if queue.TrackIndex >= 0 {

backend/playbackengine.go

@@ -20,6 +20,14 @@ var (
 	ReplayGainAuto  = "Auto"
 )
 
+type InsertQueueMode int
+
+const (
+	Replace InsertQueueMode = iota
+	InsertNext
+	Append
+)
+
 // The playback loop mode (LoopNone, LoopAll, LoopOne).
 type LoopMode int
 
@@ -200,19 +208,24 @@ func (p *playbackEngine) Continue() error {
 
 // Load tracks into the play queue.
 // If replacing the current queue (!appendToQueue), playback will be stopped.
-func (p *playbackEngine) LoadTracks(tracks []*mediaprovider.Track, appendToQueue, shuffle bool) error {
-	if !appendToQueue {
+func (p *playbackEngine) LoadTracks(tracks []*mediaprovider.Track, insertQueueMode InsertQueueMode, shuffle bool) error {
+	if insertQueueMode == Replace {
 		p.player.Stop()
 		p.nowPlayingIdx = -1
 		p.playQueue = nil
 	}
-	needToSetNext := appendToQueue && len(tracks) > 0 && p.nowPlayingIdx == len(p.playQueue)-1
+	needToSetNext := len(tracks) > 0 && (insertQueueMode == InsertNext || (insertQueueMode == Append && p.nowPlayingIdx == len(p.playQueue)-1))
 
 	newTracks := p.deepCopyTrackSlice(tracks)
 	if shuffle {
 		rand.Shuffle(len(newTracks), func(i, j int) { newTracks[i], newTracks[j] = newTracks[j], newTracks[i] })
 	}
-	p.playQueue = append(p.playQueue, newTracks...)
+
+	insertIdx := len(p.playQueue)
+	if insertQueueMode == InsertNext {
+		insertIdx = p.nowPlayingIdx + 1
+	}
+	p.playQueue = append(p.playQueue[:insertIdx], append(newTracks, p.playQueue[insertIdx:]...)...)
 
 	if needToSetNext {
 		p.setNextTrack(p.nowPlayingIdx + 1)

backend/playbackmanager.go

@@ -100,27 +100,27 @@ func (p *PlaybackManager) OnPlaying(cb func()) {
 }
 
 // Loads the specified album into the play queue.
-func (p *PlaybackManager) LoadAlbum(albumID string, appendToQueue bool, shuffle bool) error {
+func (p *PlaybackManager) LoadAlbum(albumID string, insertQueueMode InsertQueueMode, shuffle bool) error {
 	album, err := p.engine.sm.Server.GetAlbum(albumID)
 	if err != nil {
 		return err
 	}
-	return p.LoadTracks(album.Tracks, appendToQueue, shuffle)
+	return p.LoadTracks(album.Tracks, insertQueueMode, shuffle)
 }
 
 // Loads the specified playlist into the play queue.
-func (p *PlaybackManager) LoadPlaylist(playlistID string, appendToQueue bool, shuffle bool) error {
+func (p *PlaybackManager) LoadPlaylist(playlistID string, insertQueueMode InsertQueueMode, shuffle bool) error {
 	playlist, err := p.engine.sm.Server.GetPlaylist(playlistID)
 	if err != nil {
 		return err
 	}
-	return p.LoadTracks(playlist.Tracks, appendToQueue, shuffle)
+	return p.LoadTracks(playlist.Tracks, insertQueueMode, shuffle)
 }
 
 // Load tracks into the play queue.
 // If replacing the current queue (!appendToQueue), playback will be stopped.
-func (p *PlaybackManager) LoadTracks(tracks []*mediaprovider.Track, appendToQueue, shuffle bool) error {
-	return p.engine.LoadTracks(tracks, appendToQueue, shuffle)
+func (p *PlaybackManager) LoadTracks(tracks []*mediaprovider.Track, insertQueueMode InsertQueueMode, shuffle bool) error {
+	return p.engine.LoadTracks(tracks, insertQueueMode, shuffle)
 }
 
 // Replaces the play queue with the given set of tracks.
@@ -131,7 +131,7 @@ func (p *PlaybackManager) UpdatePlayQueue(tracks []*mediaprovider.Track) error {
 }
 
 func (p *PlaybackManager) PlayAlbum(albumID string, firstTrack int, shuffle bool) error {
-	if err := p.LoadAlbum(albumID, false, shuffle); err != nil {
+	if err := p.LoadAlbum(albumID, Replace, shuffle); err != nil {
 		return err
 	}
 	if p.engine.replayGainCfg.Mode == ReplayGainAuto {
@@ -141,7 +141,7 @@ func (p *PlaybackManager) PlayAlbum(albumID string, firstTrack int, shuffle bool
 }
 
 func (p *PlaybackManager) PlayPlaylist(playlistID string, firstTrack int, shuffle bool) error {
-	if err := p.LoadPlaylist(playlistID, false, shuffle); err != nil {
+	if err := p.LoadPlaylist(playlistID, Replace, shuffle); err != nil {
 		return err
 	}
 	if p.engine.replayGainCfg.Mode == ReplayGainAuto {
@@ -155,7 +155,7 @@ func (p *PlaybackManager) PlayTrack(trackID string) error {
 	if err != nil {
 		return err
 	}
-	p.LoadTracks([]*mediaprovider.Track{tr}, false, false)
+	p.LoadTracks([]*mediaprovider.Track{tr}, Replace, false)
 	if p.engine.replayGainCfg.Mode == ReplayGainAuto {
 		p.SetReplayGainMode(player.ReplayGainTrack)
 	}
@@ -186,7 +186,7 @@ func (p *PlaybackManager) fetchAndPlayTracks(fetchFn func() ([]*mediaprovider.Tr
 	if songs, err := fetchFn(); err != nil {
 		log.Printf("error fetching tracks: %s", err.Error())
 	} else {
-		p.LoadTracks(songs, false, false)
+		p.LoadTracks(songs, Replace, false)
 		if p.engine.replayGainCfg.Mode == ReplayGainAuto {
 			p.SetReplayGainMode(player.ReplayGainTrack)
 		}