🐛 | Fix prefetch bug (str vs int), move json import to module level, add missing type hints

player.py

@@ -414,6 +414,8 @@ class AudioPlayer(QObject):
         self._active_task_id: Optional[int] = None
         # The task ID of the in-progress prefetch (if any).
         self._prefetch_task_id: Optional[int] = None
+        # The video_id being prefetched (used to avoid duplicate prefetches).
+        self._prefetch_video_id: Optional[str] = None
         # Cache of prefetched results: video_id → resolved dict with _local_path.
         self._prefetch_cache: dict[str, dict] = {}
 
@@ -616,6 +618,7 @@ class AudioPlayer(QObject):
             self._worker.cancel_requested.emit()
         self._active_task_id = None
         self._prefetch_task_id = None
+        self._prefetch_video_id = None
 
     @Slot(int, dict)
     def _on_download_succeeded(self, task_id: int, song: dict) -> None:
@@ -647,6 +650,7 @@ class AudioPlayer(QObject):
         # ── Stale check for prefetch download ────────────────────────
         if task_id == self._prefetch_task_id:
             self._prefetch_task_id = None
+            self._prefetch_video_id = None
 
             vid = song.get("videoId") or song.get("video_id", "")
             # Only cache if the song is still in the active queue.
@@ -680,6 +684,7 @@ class AudioPlayer(QObject):
             self._try_next_song()
         elif task_id == self._prefetch_task_id:
             self._prefetch_task_id = None
+            self._prefetch_video_id = None
             log.debug("Prefetch failed for task %d (harmless)", task_id)
         else:
             log.debug("Ignoring stale download failure for task %d", task_id)
@@ -818,7 +823,7 @@ class AudioPlayer(QObject):
         # Already cached or already downloading.
         if vid in self._prefetch_cache:
             return
-        if vid == self._prefetch_task_id:
+        if vid == self._prefetch_video_id:
             return
         # Don't prefetch if it's already the active download target.
         if self._active_task_id is not None:
@@ -831,6 +836,7 @@ class AudioPlayer(QObject):
         task_id = self._next_task_id
         self._next_task_id += 1
         self._prefetch_task_id = task_id
+        self._prefetch_video_id = vid
 
         self._worker.download_requested.emit(task_id, next_song)