fix: add_tracks_to_collection ignores tracks that are already in the …

…collection

src/nendo/library/sqlalchemy_library.py

@@ -2208,6 +2208,23 @@ def add_tracks_to_collection(
                     "Tracks do not exist: ",
                     missing_ids,
                 )
+
+            # only add relationships that do not already exist
+            rc_rel_db = model.TrackCollectionRelationshipDB
+            existing_relationships = (
+                session.query(rc_rel_db)
+                .filter(
+                    rc_rel_db.source_id.in_(track_ids),
+                    rc_rel_db.target_id == collection_id,
+                )
+                .all()
+            )
+            existing_relationship_track_ids = [
+                rel.source_id for rel in existing_relationships
+            ]
+            track_ids = [
+                tid for tid in track_ids if tid not in existing_relationship_track_ids
+            ]
 
             # append all tracks to the end of the collection
             last_postition = (

tests/test_library.py

@@ -448,10 +448,15 @@ def test_add_tracks_to_collection(self):
             track_ids=[test_track_1.id, test_track_2.id],
             collection_id=test_collection.id,
         )
-        retrieved_test_collection = nd.library.get_collection(
+        test_collection.refresh()
+        self.assertEqual(len(test_collection), 2)
+        nd.library.add_tracks_to_collection(
+            track_ids=[test_track_1.id, test_track_2.id],
             collection_id=test_collection.id,
         )
-        self.assertEqual(len(retrieved_test_collection), 2)
+        test_collection.refresh()
+        self.assertEqual(len(test_collection), 2)
+
 
     def test_find_collections_by_empty_value(self):
         """Test finding collections by empty search value."""