feat: prevent duplicate downloads by symlinking existing music tracks before spotDL runs

apps/musicseerr/tasks.py

@@ -227,6 +227,31 @@ def send_telegram_notification(chat_id: int, text: str):
         logger.error(f"Failed to send Telegram notification: {e}")
 
 
+def symlink_existing_tracks(temp_dir: str):
+    """
+    Finds all MP3 files recursively in /remote-music/music and creates symlinks to them
+    in the temp_dir so spotDL and yt-dlp skip downloading duplicates.
+    """
+    remote_base = "/remote-music/music"
+    if not os.path.isdir(remote_base):
+        return
+        
+    logger.info(f"Scanning {remote_base} to symlink existing tracks in {temp_dir}...")
+    count = 0
+    for root, dirs, files in os.walk(remote_base):
+        for file in files:
+            if file.endswith(".mp3"):
+                src_path = os.path.join(root, file)
+                dest_path = os.path.join(temp_dir, file)
+                if not os.path.exists(dest_path):
+                    try:
+                        os.symlink(src_path, dest_path)
+                        count += 1
+                    except Exception as e:
+                        logger.warning(f"Failed to create symlink for {file}: {e}")
+    logger.info(f"Created {count} symlinks for existing tracks.")
+
+
 def run_download_task(task_id: str, query: str, proxy_url: str, jobs_dict: dict, chat_id: int = None):
     """
     Core download manager task that runs in the background.
@@ -235,6 +260,7 @@ def run_download_task(task_id: str, query: str, proxy_url: str, jobs_dict: dict,
     
     temp_dir = f"/tmp/downloads/{task_id}"
     os.makedirs(temp_dir, exist_ok=True)
+    symlink_existing_tracks(temp_dir)
     
     # Resolve proxy hostname to IP address for spotDL compatibility (spotDL requires IP in proxy URL)
     resolved_proxy_url = proxy_url
@@ -389,17 +415,27 @@ def run_download_task(task_id: str, query: str, proxy_url: str, jobs_dict: dict,
             
         # Verify files and move to /remote-music/music
         downloaded_files = os.listdir(temp_dir)
-        if not downloaded_files:
+        actual_files = [f for f in downloaded_files if not os.path.islink(os.path.join(temp_dir, f))]
+        
+        if not actual_files:
+            if downloaded_files:
+                logger.info(f"[{task_id}] All tracks in this query were already downloaded (skipped duplicates).")
+                jobs_dict[task_id]["files"] = []
+                jobs_dict[task_id]["status"] = "completed"
+                if chat_id:
+                    send_telegram_notification(chat_id, f"✅ Successfully ingested request: '{query}'\n\n(All tracks already existed - skipped duplicates)")
+                return
+            else:
                 raise Exception("Ingestion finished but no files were found in local temp folder.")
             
         os.makedirs("/remote-music/music", exist_ok=True)
         moved_files = []
         
-        for file_name in downloaded_files:
+        for file_name in actual_files:
             src_file = os.path.join(temp_dir, file_name)
             dest_file = os.path.join("/remote-music/music", file_name)
             
-            logger.info(f"[{task_id}] Moving '{file_name}' to remote Seedbox directory")
+            logger.info(f"[{task_id}] Moving new file '{file_name}' to remote Seedbox directory")
             shutil.move(src_file, dest_file)
             moved_files.append(file_name)