better lifecycle visibility implementation.

backend/app/api/subscriptions.py

@@ -7,6 +7,7 @@ from sqlalchemy.orm import selectinload
 
 from app.models.subscription import Subscription
 from app.models.source import Source
+from app.models.download import Download, DownloadStatus
 from app.tasks.downloads import download_source
 from app.api.settings import get_setting_value
 
@@ -303,16 +304,46 @@ async def trigger_subscription_check(subscription_id: int):
 
         enabled_sources = [s for s in subscription.sources if s.enabled]
 
-        # Queue Celery tasks for each enabled source
-        task_ids = []
-        for source in enabled_sources:
-            task = download_source.delay(source.id)
-            task_ids.append(task.id)
+        # Get source IDs that already have a queued or running download
+        active_result = await session.execute(
+            select(Download.source_id).where(
+                Download.source_id.in_([s.id for s in enabled_sources]),
+                Download.status.in_([DownloadStatus.QUEUED, DownloadStatus.RUNNING])
+            )
+        )
+        active_source_ids = set(active_result.scalars().all())
 
-        current_app.logger.info(f"Triggered check for subscription: {subscription.name} ({len(enabled_sources)} sources)")
+        # Create download records and queue Celery tasks for each eligible source
+        task_ids = []
+        download_ids = []
+        skipped = 0
+        for source in enabled_sources:
+            if source.id in active_source_ids:
+                skipped += 1
+                continue
+
+            download = Download(
+                source_id=source.id,
+                url=source.url,
+                status=DownloadStatus.QUEUED,
+            )
+            session.add(download)
+            await session.commit()
+            await session.refresh(download)
+
+            task = download_source.delay(source.id, download_id=download.id)
+            task_ids.append(task.id)
+            download_ids.append(download.id)
+
+        current_app.logger.info(
+            f"Triggered check for subscription: {subscription.name} "
+            f"({len(download_ids)} queued, {skipped} already active)"
+        )
         return jsonify({
             "message": "Checks queued",
             "subscription_id": subscription_id,
-            "source_count": len(enabled_sources),
+            "source_count": len(download_ids),
+            "skipped_active": skipped,
             "task_ids": task_ids,
+            "download_ids": download_ids,
         }), 202