playback: hack around paused seeking issue

Hack around an issue where the notification position will not update if
one seeked while the player was paused.

This is the best implementation I can do that will not result in the
notification getting excessively rate-limited.

CHANGELOG.md

@@ -13,9 +13,13 @@ at the cost of longer loading times
 - Search now takes sort tags and file names in account [#184]
 - Added option to clear playback state in settings
 
+#### What's Improved
+- App now exposes an (immutable) queue.
+
 #### What's Fixed
 - Fixed default material theme being used before app shows up
 - Fixed shuffle shortcut and file opening not working on startup on some devices
+- Fixed issue where the notification position would not match if one seeked when paused
 
 #### What's Changed
 - Play and skip icons are filled again

app/src/main/java/org/oxycblt/auxio/playback/system/MediaSessionComponent.kt

@@ -241,6 +241,15 @@ class MediaSessionComponent(
         reason: Int
     ) {
         invalidateSessionState()
+
+        if (!playbackManager.isPlaying) {
+            // Hack around issue where the position won't update after a seek (but only when it's
+            // paused). Apparently this can be fixed by re-posting the notification, but not always
+            // when we invalidate the state (that will cause us to be rate-limited), and also not
+            // always when we seek (that will also cause us to be rate-limited). Someone looked at
+            // this system and said it was well-designed.
+            callback.onPostNotification(notification, "position discontinuity")
+        }
     }
 
     // --- MEDIASESSION CALLBACKS ---