active source switching and reactivity

lib/database/dao/library_dao.dart

@@ -0,0 +1,63 @@
+import 'package:drift/drift.dart';
+
+import '../../sources/models.dart' as models;
+import '../database.dart';
+
+part 'library_dao.g.dart';
+
+@DriftAccessor(include: {'../tables.drift'})
+class LibraryDao extends DatabaseAccessor<SubtracksDatabase>
+    with _$LibraryDaoMixin {
+  LibraryDao(super.db);
+
+  Future<List<models.Album>> listAlbums({
+    required int limit,
+    required int offset,
+  }) {
+    final query = albums.select()
+      ..where(
+        (f) => f.sourceId.equalsExp(
+          subqueryExpression(db.sourcesDao.activeSourceId()),
+        ),
+      )
+      ..limit(limit, offset: offset);
+
+    return query.get();
+  }
+
+  Future<List<({models.Artist artist, int albumCount})>> listArtists({
+    required int limit,
+    required int offset,
+  }) async {
+    final albumCount = albums.id.count();
+
+    final query =
+        artists.select().join([
+            leftOuterJoin(
+              albums,
+              albums.artistId.equalsExp(artists.id),
+            ),
+          ])
+          ..addColumns([albumCount])
+          ..where(
+            artists.sourceId.equalsExp(
+                  subqueryExpression(db.sourcesDao.activeSourceId()),
+                ) &
+                albums.sourceId.equalsExp(
+                  subqueryExpression(db.sourcesDao.activeSourceId()),
+                ),
+          )
+          ..groupBy([artists.sourceId, artists.id])
+          ..orderBy([OrderingTerm.asc(artists.name)])
+          ..limit(limit, offset: offset);
+
+    return (await query.get())
+        .map(
+          (row) => (
+            artist: row.readTable(artists),
+            albumCount: row.read(albumCount) ?? 0,
+          ),
+        )
+        .toList();
+  }
+}