add Logout, OnLogout to server manager and hook up OnLogout callbacks

backend/playbackmanager.go

@@ -78,6 +78,10 @@ func NewPlaybackManager(ctx context.Context, s *ServerManager, p *player.Player)
 		pm.startPollTimePos()
 	})
 
+	s.OnLogout(func() {
+		pm.StopAndClearPlayQueue()
+	})
+
 	return pm
 }
 
@@ -204,6 +208,12 @@ func (p *PlaybackManager) RemoveTracksFromQueue(trackIdxs []int) {
 	}
 }
 
+// Stop playback and clear the play queue.
+func (p *PlaybackManager) StopAndClearPlayQueue() {
+	p.player.Stop()
+	p.player.ClearPlayQueue()
+}
+
 func (p *PlaybackManager) checkScrobble(playDur time.Duration) {
 	if len(p.playQueue) == 0 || p.nowPlayingIdx < 0 {
 		return

backend/servermanager.go

@@ -13,6 +13,7 @@ type ServerManager struct {
 	Server   *subsonic.Client
 
 	onServerConnected []func()
+	onLogout          []func()
 }
 
 func NewServerManager() *ServerManager {
@@ -37,10 +38,25 @@ func (s *ServerManager) ConnectToServer(conf *ServerConfig, password string) err
 	return nil
 }
 
+func (s *ServerManager) Logout() {
+	if s.Server != nil {
+		keyring.Delete(AppName, s.ServerID.String())
+		for _, cb := range s.onLogout {
+			cb()
+		}
+		s.Server = nil
+		s.ServerID = uuid.UUID{}
+	}
+}
+
 func (s *ServerManager) OnServerConnected(cb func()) {
 	s.onServerConnected = append(s.onServerConnected, cb)
 }
 
+func (s *ServerManager) OnLogout(cb func()) {
+	s.onLogout = append(s.onLogout, cb)
+}
+
 func (s *ServerManager) GetServerPassword(server *ServerConfig) (string, error) {
 	return keyring.Get(AppName, server.ID.String())
 }