feat: manual stack assets (#4198)

mobile/lib/modules/asset_viewer/providers/asset_stack.provider.dart

@@ -0,0 +1,50 @@
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:immich_mobile/shared/models/asset.dart';
+import 'package:immich_mobile/shared/providers/db.provider.dart';
+import 'package:isar/isar.dart';
+
+class AssetStackNotifier extends StateNotifier<List<Asset>> {
+  final Asset _asset;
+  final Ref _ref;
+
+  AssetStackNotifier(
+    this._asset,
+    this._ref,
+  ) : super([]) {
+    fetchStackChildren();
+  }
+
+  void fetchStackChildren() async {
+    if (mounted) {
+      state = await _ref.read(assetStackProvider(_asset).future);
+    }
+  }
+
+  removeChild(int index) {
+    if (index < state.length) {
+      state.removeAt(index);
+    }
+  }
+}
+
+final assetStackStateProvider = StateNotifierProvider.autoDispose
+    .family<AssetStackNotifier, List<Asset>, Asset>(
+  (ref, asset) => AssetStackNotifier(asset, ref),
+);
+
+final assetStackProvider =
+    FutureProvider.autoDispose.family<List<Asset>, Asset>((ref, asset) async {
+  // Guard [local asset]
+  if (asset.remoteId == null) {
+    return [];
+  }
+
+  return await ref
+      .watch(dbProvider)
+      .assets
+      .filter()
+      .isArchivedEqualTo(false)
+      .isTrashedEqualTo(false)
+      .stackParentIdEqualTo(asset.remoteId)
+      .findAll();
+});