feat(mobile): add bulk download functionality (#18878)

* feat(mobile): add bulk download functionality and update UI messages

- Added `downloadAll` method to `IDownloadRepository` and its implementation in `DownloadRepository` to handle multiple asset downloads.
- Implemented `downloadAllAsset` in `DownloadStateNotifier` to trigger bulk downloads.
- Updated `DownloadService` to create download tasks for all selected assets.
- Enhanced UI with new download success and failure messages in `en.json`.
- Added download button to `ControlBottomAppBar` and integrated download functionality in `MultiselectGrid`.

* translations use i18n method t()

* Update mobile/lib/services/download.service.dart

Co-authored-by: shenlong <139912620+shenlong-tanwen@users.noreply.github.com>

* fix(mobile): update download logic in DownloadService

- Changed the download method to utilize downloadAll for handling multiple tasks.
- Simplified remoteId check by removing unnecessary condition.

* sort i18n keys

* remove the download signature from interface and logic as we use the downloadAll now

---------

Co-authored-by: shenlong <139912620+shenlong-tanwen@users.noreply.github.com>

i18n/en.json

@@ -463,6 +463,8 @@
   "assets_count": "{count, plural, one {# asset} other {# assets}}",
   "assets_deleted_permanently": "{count} asset(s) deleted permanently",
   "assets_deleted_permanently_from_server": "{count} asset(s) deleted permanently from the Immich server",
+  "assets_downloaded_failed": "{count, plural, one {Downloaded # file - {error} file failed} other {Downloaded # files - {error} files failed}}",
+  "assets_downloaded_successfully": "{count, plural, one {Downloaded # file successfully} other {Downloaded # files successfully}}",
   "assets_moved_to_trash_count": "Moved {count, plural, one {# asset} other {# assets}} to trash",
   "assets_permanently_deleted_count": "Permanently deleted {count, plural, one {# asset} other {# assets}}",
   "assets_removed_count": "Removed {count, plural, one {# asset} other {# assets}}",
@@ -1170,7 +1172,7 @@
   "look": "Look",
   "loop_videos": "Loop videos",
   "loop_videos_description": "Enable to automatically loop a video in the detail viewer.",
-  "main_branch_warning": "You’re using a development version; we strongly recommend using a release version!",
+  "main_branch_warning": "You're using a development version; we strongly recommend using a release version!",
   "main_menu": "Main menu",
   "make": "Make",
   "manage_shared_links": "Manage shared links",
@@ -1435,7 +1437,7 @@
   "purchase_lifetime_description": "Lifetime purchase",
   "purchase_option_title": "PURCHASE OPTIONS",
   "purchase_panel_info_1": "Building Immich takes a lot of time and effort, and we have full-time engineers working on it to make it as good as we possibly can. Our mission is for open-source software and ethical business practices to become a sustainable income source for developers and to create a privacy-respecting ecosystem with real alternatives to exploitative cloud services.",
-  "purchase_panel_info_2": "As we’re committed not to add paywalls, this purchase will not grant you any additional features in Immich. We rely on users like you to support Immich’s ongoing development.",
+  "purchase_panel_info_2": "As we're committed not to add paywalls, this purchase will not grant you any additional features in Immich. We rely on users like you to support Immich's ongoing development.",
   "purchase_panel_title": "Support the project",
   "purchase_per_server": "Per server",
   "purchase_per_user": "Per user",

mobile/lib/interfaces/download.interface.dart

@@ -7,7 +7,8 @@ abstract interface class IDownloadRepository {
   void Function(TaskProgressUpdate)? onTaskProgress;
 
   Future<List<TaskRecord>> getLiveVideoTasks();
-  Future<bool> download(DownloadTask task);
+  Future<List<bool>> downloadAll(List<DownloadTask> tasks);
+
   Future<bool> cancel(String id);
   Future<void> deleteAllTrackingRecords();
   Future<void> deleteRecordsWithIds(List<String> id);

mobile/lib/models/asset_selection_state.dart

@@ -35,7 +35,7 @@ class AssetSelectionState {
 
   @override
   String toString() =>
-      'SelectionAssetState(hasRemote: $hasRemote, hasMerged: $hasMerged, hasMerged: $hasMerged, selectedCount: $selectedCount)';
+      'SelectionAssetState(hasRemote: $hasRemote, hasLocal: $hasLocal, hasMerged: $hasMerged, selectedCount: $selectedCount)';
 
   @override
   bool operator ==(covariant AssetSelectionState other) {

mobile/lib/providers/asset_viewer/download.provider.dart

@@ -140,6 +140,10 @@ class DownloadStateNotifier extends StateNotifier<DownloadState> {
     });
   }
 
+  Future<List<bool>> downloadAllAsset(List<Asset> assets) async {
+    return await _downloadService.downloadAll(assets);
+  }
+
   void downloadAsset(Asset asset, BuildContext context) async {
     await _downloadService.download(asset);
   }

mobile/lib/repositories/download.repository.dart

@@ -39,8 +39,8 @@ class DownloadRepository implements IDownloadRepository {
   }
 
   @override
-  Future<bool> download(DownloadTask task) {
-    return FileDownloader().enqueue(task);
+  Future<List<bool>> downloadAll(List<DownloadTask> tasks) {
+    return FileDownloader().enqueueAll(tasks);
   }
 
   @override

mobile/lib/services/download.service.dart

@@ -159,9 +159,19 @@ class DownloadService {
     return await FileDownloader().cancelTaskWithId(id);
   }
 
+  Future<List<bool>> downloadAll(List<Asset> assets) async {
+    return await _downloadRepository
+        .downloadAll(assets.expand(_createDownloadTasks).toList());
+  }
+
   Future<void> download(Asset asset) async {
+    final tasks = _createDownloadTasks(asset);
+    await _downloadRepository.downloadAll(tasks);
+  }
+
+  List<DownloadTask> _createDownloadTasks(Asset asset) {
     if (asset.isImage && asset.livePhotoVideoId != null && Platform.isIOS) {
-      await _downloadRepository.download(
+      return [
         _buildDownloadTask(
           asset.remoteId!,
           asset.fileName,
@@ -171,9 +181,6 @@ class DownloadService {
             id: asset.remoteId!,
           ).toJson(),
         ),
-      );
-
-      await _downloadRepository.download(
         _buildDownloadTask(
           asset.livePhotoVideoId!,
           asset.fileName
@@ -185,16 +192,20 @@ class DownloadService {
             id: asset.remoteId!,
           ).toJson(),
         ),
-      );
-    } else {
-      await _downloadRepository.download(
-        _buildDownloadTask(
-          asset.remoteId!,
-          asset.fileName,
-          group: asset.isImage ? downloadGroupImage : downloadGroupVideo,
-        ),
-      );
+      ];
     }
+
+    if (asset.remoteId == null) {
+      return [];
+    }
+
+    return [
+      _buildDownloadTask(
+        asset.remoteId!,
+        asset.fileName,
+        group: asset.isImage ? downloadGroupImage : downloadGroupVideo,
+      ),
+    ];
   }
 
   DownloadTask _buildDownloadTask(

mobile/lib/widgets/asset_grid/control_bottom_app_bar.dart

@@ -39,6 +39,7 @@ class ControlBottomAppBar extends HookConsumerWidget {
   final void Function()? onEditLocation;
   final void Function()? onRemoveFromAlbum;
   final void Function()? onToggleLocked;
+  final void Function()? onDownload;
 
   final bool enabled;
   final bool unfavorite;
@@ -56,6 +57,7 @@ class ControlBottomAppBar extends HookConsumerWidget {
     required this.onAddToAlbum,
     required this.onCreateNewAlbum,
     required this.onUpload,
+    this.onDownload,
     this.onStack,
     this.onEditTime,
     this.onEditLocation,
@@ -158,6 +160,15 @@ class ControlBottomAppBar extends HookConsumerWidget {
             label: (unfavorite ? "unfavorite" : "favorite").tr(),
             onPressed: enabled ? onFavorite : null,
           ),
+        if (hasRemote && onDownload != null)
+          ConstrainedBox(
+            constraints: const BoxConstraints(maxWidth: 90),
+            child: ControlBoxButton(
+              iconData: Icons.download,
+              label: "download".tr(),
+              onPressed: onDownload,
+            ),
+          ),
         if (hasLocal && hasRemote && onDelete != null && !isInLockedView)
           ConstrainedBox(
             constraints: const BoxConstraints(maxWidth: 90),

mobile/lib/widgets/asset_grid/multiselect_grid.dart

@@ -14,6 +14,7 @@ import 'package:immich_mobile/extensions/collection_extensions.dart';
 import 'package:immich_mobile/models/asset_selection_state.dart';
 import 'package:immich_mobile/providers/album/album.provider.dart';
 import 'package:immich_mobile/providers/asset.provider.dart';
+import 'package:immich_mobile/providers/asset_viewer/download.provider.dart';
 import 'package:immich_mobile/providers/backup/manual_upload.provider.dart';
 import 'package:immich_mobile/providers/multiselect.provider.dart';
 import 'package:immich_mobile/providers/routes.provider.dart';
@@ -23,6 +24,7 @@ import 'package:immich_mobile/services/album.service.dart';
 import 'package:immich_mobile/services/stack.service.dart';
 import 'package:immich_mobile/utils/immich_loading_overlay.dart';
 import 'package:immich_mobile/utils/selection_handlers.dart';
+import 'package:immich_mobile/utils/translation.dart';
 import 'package:immich_mobile/widgets/asset_grid/asset_grid_data_structure.dart';
 import 'package:immich_mobile/widgets/asset_grid/control_bottom_app_bar.dart';
 import 'package:immich_mobile/widgets/asset_grid/immich_asset_grid.dart';
@@ -44,6 +46,7 @@ class MultiselectGrid extends HookConsumerWidget {
     this.editEnabled = false,
     this.unarchive = false,
     this.unfavorite = false,
+    this.downloadEnabled = true,
     this.emptyIndicator,
   });
 
@@ -57,6 +60,7 @@ class MultiselectGrid extends HookConsumerWidget {
   final bool archiveEnabled;
   final bool unarchive;
   final bool deleteEnabled;
+  final bool downloadEnabled;
   final bool favoriteEnabled;
   final bool unfavorite;
   final bool editEnabled;
@@ -239,6 +243,39 @@ class MultiselectGrid extends HookConsumerWidget {
       }
     }
 
+    void onDownload() async {
+      processing.value = true;
+      try {
+        final toDownload = selection.value.toList();
+
+        final results = await ref
+            .read(downloadStateProvider.notifier)
+            .downloadAllAsset(toDownload);
+
+        final totalCount = toDownload.length;
+        final successCount = results.where((e) => e).length;
+        final failedCount = totalCount - successCount;
+
+        final msg = failedCount > 0
+            ? t('assets_downloaded_failed', {
+                'count': successCount,
+                'error': failedCount,
+              })
+            : t('assets_downloaded_successfully', {
+                'count': successCount,
+              });
+
+        ImmichToast.show(
+          context: context,
+          msg: msg,
+          gravity: ToastGravity.BOTTOM,
+        );
+      } finally {
+        processing.value = false;
+        selectionEnabledHook.value = false;
+      }
+    }
+
     void onDeleteRemote([bool shouldDeletePermanently = false]) async {
       processing.value = true;
       try {
@@ -474,6 +511,7 @@ class MultiselectGrid extends HookConsumerWidget {
               onArchive: archiveEnabled ? onArchiveAsset : null,
               onDelete: deleteEnabled ? onDelete : null,
               onDeleteServer: deleteEnabled ? onDeleteRemote : null,
+              onDownload: downloadEnabled ? onDownload : null,
 
               /// local file deletion is allowed irrespective of [deleteEnabled] since it has
               /// nothing to do with the state of the asset in the Immich server