fix(mobile): show real error when an asset can't be added to an album

mobile/lib/domain/services/remote_album.service.dart

@@ -175,12 +175,12 @@ class RemoteAlbumService {
     return _repository.getAssets(albumId);
   }
 
-  Future<int> addAssets({required String albumId, required List<String> assetIds}) async {
+  Future<({int added, int failed})> addAssets({required String albumId, required List<String> assetIds}) async {
     final album = await _albumApiRepository.addAssets(albumId, assetIds);
 
     await _repository.addAssets(albumId, album.added);
 
-    return album.added.length;
+    return (added: album.added.length, failed: album.failed.length);
   }
 
   /// !TODO The name here is not clear as we have addAssets method above,
@@ -196,7 +196,7 @@ class RemoteAlbumService {
   }) async {
     int addedCount = 0;
     if (candidates.remoteAssetIds.isNotEmpty) {
-      addedCount += await addAssets(albumId: albumId, assetIds: candidates.remoteAssetIds);
+      addedCount += (await addAssets(albumId: albumId, assetIds: candidates.remoteAssetIds)).added;
     }
     if (candidates.localAssetsToUpload.isNotEmpty) {
       addedCount += await _uploadAndAddLocals(

mobile/lib/presentation/widgets/action_buttons/add_action_button.widget.dart

@@ -2,6 +2,7 @@ import 'package:easy_localization/easy_localization.dart';
 import 'package:flutter/material.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 import 'package:immich_mobile/extensions/build_context_extensions.dart';
+import 'package:immich_mobile/extensions/translate_extensions.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/base_action_button.widget.dart';
 import 'package:immich_mobile/presentation/widgets/action_buttons/unarchive_action_button.widget.dart';
 import 'package:immich_mobile/providers/asset_viewer/asset_viewer.provider.dart';
@@ -154,7 +155,13 @@ class _AddActionButtonState extends ConsumerState<AddActionButton> {
       return;
     }
 
-    if (result.count == 0) {
+    if (result.count == 0 && result.failedCount > 0) {
+      ImmichToast.show(
+        context: context,
+        msg: 'assets_cannot_be_added_to_album_count'.t(context: context, args: {'count': result.failedCount}),
+        toastType: ToastType.error,
+      );
+    } else if (result.count == 0) {
       ImmichToast.show(
         context: context,
         msg: 'add_to_album_bottom_sheet_already_exists'.tr(namedArgs: {'album': album.name}),

mobile/lib/presentation/widgets/bottom_sheet/favorite_bottom_sheet.widget.dart

@@ -41,7 +41,7 @@ class FavoriteBottomSheet extends ConsumerWidget {
       }
 
       final remoteAssets = selectedAssets.whereType<RemoteAsset>();
-      final addedCount = await ref
+      final result = await ref
           .read(remoteAlbumProvider.notifier)
           .addAssets(album.id, remoteAssets.map((e) => e.id).toList());
 
@@ -52,7 +52,13 @@ class FavoriteBottomSheet extends ConsumerWidget {
         );
       }
 
-      if (addedCount != remoteAssets.length) {
+      if (result.added == 0 && result.failed > 0) {
+        ImmichToast.show(
+          context: context,
+          msg: 'assets_cannot_be_added_to_album_count'.t(context: context, args: {'count': result.failed}),
+          toastType: ToastType.error,
+        );
+      } else if (result.added != remoteAssets.length) {
         ImmichToast.show(
           context: context,
           msg: 'add_to_album_bottom_sheet_already_exists'.t(args: {"album": album.name}),

mobile/lib/providers/infrastructure/action.provider.dart

@@ -37,11 +37,19 @@ class ActionResult {
   final bool success;
   final String? error;
   final List<String> remoteAssetIds;
+  final int failedCount;
 
-  const ActionResult({required this.count, required this.success, this.error, this.remoteAssetIds = const []});
+  const ActionResult({
+    required this.count,
+    required this.success,
+    this.error,
+    this.remoteAssetIds = const [],
+    this.failedCount = 0,
+  });
 
   @override
-  String toString() => 'ActionResult(count: $count, success: $success, error: $error, remoteAssetIds: $remoteAssetIds)';
+  String toString() =>
+      'ActionResult(count: $count, success: $success, error: $error, remoteAssetIds: $remoteAssetIds, failedCount: $failedCount)';
 }
 
 class ActionNotifier extends Notifier<void> {
@@ -393,9 +401,12 @@ class ActionNotifier extends Notifier<void> {
     final albumNotifier = ref.read(remoteAlbumProvider.notifier);
 
     int addedRemote = 0;
+    int failedRemote = 0;
     if (remoteIds.isNotEmpty) {
       try {
-        addedRemote = await albumNotifier.addAssets(album.id, remoteIds);
+        final result = await albumNotifier.addAssets(album.id, remoteIds);
+        addedRemote = result.added;
+        failedRemote = result.failed;
       } catch (error, stack) {
         _logger.severe('Failed to add assets to album ${album.id}', error, stack);
         return ActionResult(count: 0, success: false, error: error.toString());
@@ -409,7 +420,7 @@ class ActionNotifier extends Notifier<void> {
     }
 
     if (localAssets.isEmpty) {
-      return ActionResult(count: addedRemote, success: true);
+      return ActionResult(count: addedRemote, success: true, failedCount: failedRemote);
     }
 
     final uploadResult = await upload(
@@ -424,6 +435,7 @@ class ActionNotifier extends Notifier<void> {
       count: addedRemote + uploadResult.count,
       success: uploadResult.success,
       error: uploadResult.error,
+      failedCount: failedRemote,
     );
   }
 

mobile/lib/providers/infrastructure/remote_album.provider.dart

@@ -200,12 +200,12 @@ class RemoteAlbumNotifier extends Notifier<RemoteAlbumState> {
     return _remoteAlbumService.getAssets(albumId);
   }
 
-  Future<int> addAssets(String albumId, List<String> assetIds) async {
-    final added = await _remoteAlbumService.addAssets(albumId: albumId, assetIds: assetIds);
-    if (added > 0) {
+  Future<({int added, int failed})> addAssets(String albumId, List<String> assetIds) async {
+    final result = await _remoteAlbumService.addAssets(albumId: albumId, assetIds: assetIds);
+    if (result.added > 0) {
       await _refreshAlbumInState(albumId);
     }
-    return added;
+    return result;
   }
 
   /// Links a freshly-uploaded local asset to an album using its new remote ID,

mobile/lib/repositories/drift_album_api_repository.dart

@@ -59,7 +59,7 @@ class DriftAlbumApiRepository extends ApiRepository {
     for (final dto in response) {
       if (dto.success) {
         added.add(dto.id);
-      } else {
+      } else if (dto.error.orElse(null) != BulkIdErrorReason.duplicate) {
         failed.add(dto.id);
       }
     }

mobile/test/repositories/drift_album_api_repository_test.dart

@@ -0,0 +1,82 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:immich_mobile/repositories/drift_album_api_repository.dart';
+import 'package:mocktail/mocktail.dart';
+import 'package:openapi/api.dart';
+
+class _MockAlbumsApi extends Mock implements AlbumsApi {}
+
+void main() {
+  late _MockAlbumsApi api;
+  late DriftAlbumApiRepository repo;
+
+  setUpAll(() {
+    registerFallbackValue(BulkIdsDto(ids: const []));
+  });
+
+  setUp(() {
+    api = _MockAlbumsApi();
+    repo = DriftAlbumApiRepository(api);
+  });
+
+  void stubResponse(List<BulkIdResponseDto> response) {
+    when(
+      () => api.addAssetsToAlbum(any(), any(), abortTrigger: any(named: 'abortTrigger')),
+    ).thenAnswer((_) async => response);
+  }
+
+  test('no_permission failure surfaces as failed, not added (the #22342 bug)', () async {
+    stubResponse([
+      BulkIdResponseDto(id: 'a1', success: false, error: const Optional.present(BulkIdErrorReason.noPermission)),
+    ]);
+
+    final result = await repo.addAssets('album1', ['a1']);
+
+    expect(result.added, isEmpty);
+    expect(result.failed, ['a1']);
+  });
+
+  test('duplicate is neither added nor failed (genuinely already in album)', () async {
+    stubResponse([
+      BulkIdResponseDto(id: 'a1', success: false, error: const Optional.present(BulkIdErrorReason.duplicate)),
+    ]);
+
+    final result = await repo.addAssets('album1', ['a1']);
+
+    expect(result.added, isEmpty);
+    expect(result.failed, isEmpty);
+  });
+
+  test('success is added', () async {
+    stubResponse([BulkIdResponseDto(id: 'a1', success: true)]);
+
+    final result = await repo.addAssets('album1', ['a1']);
+
+    expect(result.added, ['a1']);
+    expect(result.failed, isEmpty);
+  });
+
+  test('not_found and unknown count as failures', () async {
+    stubResponse([
+      BulkIdResponseDto(id: 'a1', success: false, error: const Optional.present(BulkIdErrorReason.notFound)),
+      BulkIdResponseDto(id: 'a2', success: false, error: const Optional.present(BulkIdErrorReason.unknown)),
+    ]);
+
+    final result = await repo.addAssets('album1', ['a1', 'a2']);
+
+    expect(result.added, isEmpty);
+    expect(result.failed, ['a1', 'a2']);
+  });
+
+  test('mixed: added kept, no_permission failed, duplicate dropped', () async {
+    stubResponse([
+      BulkIdResponseDto(id: 'ok', success: true),
+      BulkIdResponseDto(id: 'perm', success: false, error: const Optional.present(BulkIdErrorReason.noPermission)),
+      BulkIdResponseDto(id: 'dup', success: false, error: const Optional.present(BulkIdErrorReason.duplicate)),
+    ]);
+
+    final result = await repo.addAssets('album1', ['ok', 'perm', 'dup']);
+
+    expect(result.added, ['ok']);
+    expect(result.failed, ['perm']);
+  });
+}