cleanup history entries after db update

- delete history entries without album/artist
- fix #37

src/lib/system/datasources/moor/music_data_dao.dart

@@ -418,4 +418,41 @@ class MusicDataDao extends DatabaseAccessor<MoorDatabase>
       batch.deleteWhere<$BlockedFilesTable, dynamic>(blockedFiles, (tbl) => tbl.path.isIn(paths));
     });
   }
+
+  @override
+  Future<void> cleanupDatabase() async {
+    // get album history entries
+    final albumHistoryEntries = await (select(historyEntries)
+          ..where((tbl) => tbl.type.equals(PlayableType.album.toString())))
+        .get();
+
+    // delete history entries with missing album
+    for (final entry in albumHistoryEntries) {
+      if ((await (select(albums)..where((tbl) => tbl.id.equals(int.parse(entry.identifier)))).get())
+          .isEmpty) {
+        (delete(historyEntries)
+              ..where((tbl) =>
+                  tbl.type.equals(PlayableType.album.toString()) &
+                  tbl.identifier.equals(entry.identifier)))
+            .go();
+      }
+    }
+
+    // get album history entries
+    final artistHistoryEntries = await (select(historyEntries)
+          ..where((tbl) => tbl.type.equals(PlayableType.artist.toString())))
+        .get();
+
+    // delete history entries with missing album
+    for (final entry in artistHistoryEntries) {
+      if ((await (select(artists)..where((tbl) => tbl.id.equals(int.parse(entry.identifier)))).get())
+          .isEmpty) {
+        (delete(historyEntries)
+              ..where((tbl) =>
+                  tbl.type.equals(PlayableType.artist.toString()) &
+                  tbl.identifier.equals(entry.identifier)))
+            .go();
+      }
+    }
+  }
 }

src/lib/system/datasources/music_data_source_contract.dart

@@ -39,4 +39,6 @@ abstract class MusicDataSource {
   Stream<Set<String>> get blockedFilesStream;
   Future<void> addBlockedFiles(List<String> paths);
   Future<void> removeBlockedFiles(List<String> paths);
+
+  Future<void> cleanupDatabase();
 }

src/lib/system/repositories/music_data_repository_impl.dart

@@ -128,6 +128,8 @@ class MusicDataRepositoryImpl implements MusicDataRepository {
     await _updateAlbums(albums);
     await _musicDataSource.insertSongs(songs);
 
+    await _musicDataSource.cleanupDatabase();
+
     _log.d('updateDatabase finished');
 
     _updateHighlightStreams();