Fix load queue seeking

* Add method for mpvplayer to check if the player is allowed to seek

* Make the load queue functionality seek to the saved position when mpv is ready to seek

mpvplayer/player.go

@@ -151,6 +151,11 @@ func (p *Player) IsSongLoaded() (bool, error) {
 	return !idle, err
 }
 
+func (p *Player) IsSeekable() (bool, error) {
+	seekable, err := p.getPropertyBool("seekable")
+	return seekable, err
+}
+
 func (p *Player) IsPaused() (bool, error) {
 	pause, err := p.getPropertyBool("pause")
 	return pause, err

page_queue.go

@@ -127,10 +127,16 @@ func (ui *Ui) createQueuePage() *QueuePage {
 						if err := ui.player.Play(); err != nil {
 							queuePage.logger.Printf("error playing: %s", err)
 						}
+						_ = ui.player.Pause()
+						for {
+							if seekable, err := ui.player.IsSeekable(); err == nil && seekable {
+								break
+							}
+							time.Sleep(100 * time.Millisecond)
+						}
 						if err = ui.player.Seek(ssr.PlayQueue.Position); err != nil {
 							queuePage.logger.Printf("unable to seek to position %s: %s", time.Duration(ssr.PlayQueue.Position)*time.Second, err)
 						}
-						_ = ui.player.Pause()
 					}
 				}()