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())
 }

player/player.go

@@ -159,6 +159,14 @@ func (p *Player) Stop() error {
 	return err
 }
 
+// Clears the play queue, except for the currently playing file.
+func (p *Player) ClearPlayQueue() error {
+	if p.mpv == nil {
+		return ErrUnitialized
+	}
+	return p.mpv.Command([]string{"playlist-clear"})
+}
+
 // Seeks within the currently playing track.
 // See MPV seek command documentation for more details.
 func (p *Player) Seek(target string, mode SeekMode) error {

ui/browsing/browsingpane.go

@@ -76,16 +76,37 @@ func NewBrowsingPane(app *backend.App) *BrowsingPane {
 }
 
 func (b *BrowsingPane) SetPage(p Page) {
+	if p == nil {
+		b.doSetPage(&blankPage{})
+		return
+	}
 	oldPage := b.curPage
 	if b.doSetPage(p) && oldPage != nil {
 		b.addPageToHistory(oldPage, true)
 	}
 }
 
+func (b *BrowsingPane) ClearHistory() {
+	b.history = nil
+	b.historyIdx = 0
+}
+
 func (b *BrowsingPane) AddNavigationButton(iconRes fyne.Resource, action func()) {
 	b.navBtnsContainer.Add(widget.NewButtonWithIcon("", iconRes, action))
 }
 
+func (b *BrowsingPane) DisableNavigationButtons() {
+	for _, obj := range b.navBtnsContainer.Objects {
+		obj.(*widget.Button).Disable()
+	}
+}
+
+func (b *BrowsingPane) EnableNavigationButtons() {
+	for _, obj := range b.navBtnsContainer.Objects {
+		obj.(*widget.Button).Enable()
+	}
+}
+
 func (b *BrowsingPane) GetSearchBarIfAny() fyne.Focusable {
 	if s, ok := b.curPage.(Searchable); ok {
 		return s.SearchWidget()
@@ -162,3 +183,17 @@ func (b *BrowsingPane) Reload() {
 func (b *BrowsingPane) CreateRenderer() fyne.WidgetRenderer {
 	return widget.NewSimpleRenderer(b.container)
 }
+
+type blankPage struct {
+	layout.Spacer
+}
+
+var _ Page = (*blankPage)(nil)
+
+func (p *blankPage) Reload() {}
+
+func (p *blankPage) Route() Route { return Route{Page: Blank} }
+
+func (p *blankPage) Save() SavedPage { return p }
+
+func (p *blankPage) Restore() Page { return p }

ui/mainwindow.go

@@ -64,8 +64,15 @@ func NewMainWindow(fyneApp fyne.App, appName string, app *backend.App, size fyne
 		m.Window.SetTitle(song.Title)
 	})
 	app.ServerManager.OnServerConnected(func() {
+		m.BrowsingPane.EnableNavigationButtons()
 		m.Router.OpenRoute(HomePage)
 	})
+	app.ServerManager.OnLogout(func() {
+		m.BrowsingPane.DisableNavigationButtons()
+		m.BrowsingPane.SetPage(nil)
+		m.BrowsingPane.ClearHistory()
+		// TODO: show prompt for login
+	})
 	m.addNavigationButtons()
 	m.addShortcuts()
 	return m