Implemented Deezspot-compliant error reporting on the backend

routes/utils/celery_queue_manager.py

@@ -83,6 +83,89 @@ def get_config_params():
         }
 
 
+def get_existing_task_id(url, download_type=None):
+    """
+    Check if an active task with the same URL (and optionally, type) already exists.
+    This function ignores tasks that are in a terminal state (e.g., completed, cancelled, or failed).
+
+    Args:
+        url (str): The URL to check for duplicates.
+        download_type (str, optional): The type of download to check. Defaults to None.
+
+    Returns:
+        str | None: The task ID of the existing active task, or None if no active duplicate is found.
+    """
+    logger.debug(f"GET_EXISTING_TASK_ID: Checking for URL='{url}', type='{download_type}'")
+    if not url:
+        logger.debug("GET_EXISTING_TASK_ID: No URL provided, returning None.")
+        return None
+
+    # Define terminal states. Tasks in these states are considered inactive and will be ignored.
+    TERMINAL_STATES = {
+        ProgressState.COMPLETE,
+        ProgressState.DONE,
+        ProgressState.CANCELLED,
+        ProgressState.ERROR,
+        ProgressState.ERROR_RETRIED,
+        ProgressState.ERROR_AUTO_CLEANED,
+    }
+    logger.debug(f"GET_EXISTING_TASK_ID: Terminal states defined as: {TERMINAL_STATES}")
+
+    all_existing_tasks_summary = get_all_tasks() # This function already filters by default based on its own TERMINAL_STATES
+    logger.debug(f"GET_EXISTING_TASK_ID: Found {len(all_existing_tasks_summary)} tasks from get_all_tasks(). Iterating...")
+
+    for task_summary in all_existing_tasks_summary:
+        existing_task_id = task_summary.get("task_id")
+        if not existing_task_id:
+            logger.debug("GET_EXISTING_TASK_ID: Skipping summary with no task_id.")
+            continue
+        
+        logger.debug(f"GET_EXISTING_TASK_ID: Processing existing task_id='{existing_task_id}' from summary.")
+
+        # First, check the status of the task directly from its latest status record.
+        # get_all_tasks() might have its own view of terminal, but we re-check here for absolute certainty.
+        existing_last_status_obj = get_last_task_status(existing_task_id)
+        if not existing_last_status_obj:
+            logger.debug(f"GET_EXISTING_TASK_ID: No last status object for task_id='{existing_task_id}'. Skipping.")
+            continue
+        
+        existing_status = existing_last_status_obj.get("status")
+        logger.debug(f"GET_EXISTING_TASK_ID: Task_id='{existing_task_id}', last_status_obj='{existing_last_status_obj}', extracted status='{existing_status}'.")
+
+        # If the task is in a terminal state, ignore it and move to the next one.
+        if existing_status in TERMINAL_STATES:
+            logger.debug(f"GET_EXISTING_TASK_ID: Task_id='{existing_task_id}' has terminal status='{existing_status}'. Skipping.")
+            continue
+        
+        logger.debug(f"GET_EXISTING_TASK_ID: Task_id='{existing_task_id}' has ACTIVE status='{existing_status}'. Proceeding to check URL/type.")
+
+        # If the task is active, then check if its URL and type match.
+        existing_task_info = get_task_info(existing_task_id)
+        if not existing_task_info:
+            logger.debug(f"GET_EXISTING_TASK_ID: No task info for active task_id='{existing_task_id}'. Skipping.")
+            continue
+
+        existing_url = existing_task_info.get("url")
+        logger.debug(f"GET_EXISTING_TASK_ID: Task_id='{existing_task_id}', info_url='{existing_url}'. Comparing with target_url='{url}'.")
+        if existing_url != url:
+            logger.debug(f"GET_EXISTING_TASK_ID: Task_id='{existing_task_id}' URL mismatch. Skipping.")
+            continue
+
+        if download_type:
+            existing_type = existing_task_info.get("download_type")
+            logger.debug(f"GET_EXISTING_TASK_ID: Task_id='{existing_task_id}', info_type='{existing_type}'. Comparing with target_type='{download_type}'.")
+            if existing_type != download_type:
+                logger.debug(f"GET_EXISTING_TASK_ID: Task_id='{existing_task_id}' type mismatch. Skipping.")
+                continue
+
+        # Found an active task that matches the criteria.
+        logger.info(f"GET_EXISTING_TASK_ID: Found ACTIVE duplicate: task_id='{existing_task_id}' for URL='{url}', type='{download_type}'. Returning this ID.")
+        return existing_task_id
+
+    logger.debug(f"GET_EXISTING_TASK_ID: No active duplicate found for URL='{url}', type='{download_type}'. Returning None.")
+    return None
+
+
 class CeleryDownloadQueueManager:
     """
     Manages a queue of download tasks using Celery.
@@ -125,14 +208,14 @@ class CeleryDownloadQueueManager:
                     "Task being added with no URL. Duplicate check might be unreliable."
                 )
 
-            NON_BLOCKING_STATES = [
+            TERMINAL_STATES = {  # Renamed and converted to a set for consistency
                 ProgressState.COMPLETE,
                 ProgressState.DONE,
                 ProgressState.CANCELLED,
                 ProgressState.ERROR,
                 ProgressState.ERROR_RETRIED,
                 ProgressState.ERROR_AUTO_CLEANED,
-            ]
+            }
 
             all_existing_tasks_summary = get_all_tasks()
             if incoming_url:
@@ -154,7 +237,7 @@ class CeleryDownloadQueueManager:
                     if (
                         existing_url == incoming_url
                         and existing_type == incoming_type
-                        and existing_status not in NON_BLOCKING_STATES
+                        and existing_status not in TERMINAL_STATES
                     ):
                         message = f"Duplicate download: URL '{incoming_url}' (type: {incoming_type}) is already being processed by task {existing_task_id} (status: {existing_status})."
                         logger.warning(message)