Add smart-skip to sync playlist node for efficient scheduled syncing

Sync now compares current discovered track count against last sync's
matched count. Skips when all discovered tracks are already on the server.
Re-syncs when wishlist may have downloaded missing tracks since last sync.
Saves matched/discovered/total counts to sync status after each run.

Enables putting sync on a schedule without wasting resources — it skips
instantly when nothing changed and only runs when there's something new.

web_server.py

@@ -713,7 +713,8 @@ def _register_automation_handlers():
 
     def _auto_sync_playlist(config):
         """Sync a mirrored playlist to media server.
-        Uses discovered metadata when available, skips undiscovered tracks."""
+        Uses discovered metadata when available, skips undiscovered tracks.
+        When triggered on a schedule, skips if nothing changed since last sync."""
         auto_id = config.get('_automation_id')
         playlist_id = config.get('playlist_id')
         if not playlist_id:
@@ -728,6 +729,44 @@ def _register_automation_handlers():
         if not tracks:
             return {'status': 'error', 'reason': 'No tracks in playlist'}
 
+        # Count currently discovered tracks for smart-skip check
+        current_discovered = 0
+        for t in tracks:
+            extra = {}
+            if t.get('extra_data'):
+                try:
+                    extra = json.loads(t['extra_data']) if isinstance(t['extra_data'], str) else t['extra_data']
+                except (json.JSONDecodeError, TypeError):
+                    pass
+            if extra.get('discovered') and extra.get('matched_data'):
+                current_discovered += 1
+
+        # Smart skip: only re-sync if something could have changed
+        # Skip when: same discovered count, same total, AND last sync already matched all discovered tracks
+        # Re-sync when: new tracks discovered, tracks added/removed, or last sync had unmatched tracks
+        #   (unmatched = discovered but not on server — wishlist may have downloaded them since)
+        sync_id_key = f"auto_mirror_{playlist_id}"
+        try:
+            sync_statuses = _load_sync_status_file()
+            last_status = sync_statuses.get(sync_id_key, {})
+            last_matched = last_status.get('matched_tracks', -1)
+            last_discovered = last_status.get('discovered_tracks', -1)
+            last_total = last_status.get('total_tracks', -1)
+
+            if (last_discovered == current_discovered and
+                last_total == len(tracks) and
+                last_matched >= current_discovered):
+                # All discovered tracks were already matched on server last time — nothing to do
+                _update_automation_progress(auto_id,
+                    log_line=f'All {current_discovered} tracks already synced — skipping',
+                    log_type='skip')
+                return {
+                    'status': 'skipped',
+                    'reason': f'All {current_discovered} tracks already synced',
+                }
+        except Exception:
+            pass  # If we can't read last status, just run the sync
+
         # Convert mirrored tracks to format expected by _run_sync_task
         # Use discovered metadata when available, skip undiscovered tracks
         tracks_json = []
@@ -23985,21 +24024,26 @@ def _save_sync_status_file(sync_statuses):
     except Exception as e:
         print(f"❌ Error saving sync status: {e}")
 
-def _update_and_save_sync_status(playlist_id, playlist_name, playlist_owner, snapshot_id):
+def _update_and_save_sync_status(playlist_id, playlist_name, playlist_owner, snapshot_id, **kwargs):
     """Updates the sync status for a given playlist and saves to file (same logic as GUI)."""
     try:
         # Load existing sync statuses
         sync_statuses = _load_sync_status_file()
-        
+
         # Update this playlist's sync status
         from datetime import datetime
         now = datetime.now()
-        sync_statuses[playlist_id] = {
+        status = {
             'name': playlist_name,
             'owner': playlist_owner,
             'snapshot_id': snapshot_id,
             'last_synced': now.isoformat()
         }
+        # Store match counts for smart-skip on scheduled syncs
+        for key in ('matched_tracks', 'total_tracks', 'discovered_tracks'):
+            if key in kwargs:
+                status[key] = kwargs[key]
+        sync_statuses[playlist_id] = status
         
         # Save to file
         _save_sync_status_file(sync_statuses)
@@ -29236,10 +29280,12 @@ def _run_sync_task(playlist_id, playlist_name, tracks_json, automation_id=None):
         except Exception:
             pass
 
-        # Save sync status to storage/sync_status.json (same as GUI)
-        # Handle snapshot_id safely - may not exist in all playlist objects
+        # Save sync status with match counts for smart-skip on next scheduled sync
         snapshot_id = getattr(playlist, 'snapshot_id', None)
-        _update_and_save_sync_status(playlist_id, playlist_name, playlist.owner, snapshot_id)
+        _update_and_save_sync_status(playlist_id, playlist_name, playlist.owner, snapshot_id,
+            matched_tracks=getattr(result, 'matched_tracks', 0),
+            total_tracks=getattr(result, 'total_tracks', 0),
+            discovered_tracks=len(tracks_json))
 
     except Exception as e:
         print(f"❌ SYNC FAILED for {playlist_id}: {e}")