feat: Background download on iOS (#1442)

ui/flutter/lib/api/api.dart

@@ -99,6 +99,17 @@ void init(String network, String address, String apiToken) {
   _client = _Client(network, address, apiToken);
 }
 
+/// Used by LocationKeepAliveCoordinator to reconcile keep-alive
+void Function()? _onTaskChanged;
+
+void setTaskChangedListener(void Function() listener) {
+  _onTaskChanged = listener;
+}
+
+void _notifyTaskChanged() {
+  _onTaskChanged?.call();
+}
+
 Future<T> _parse<T>(
   Future<Response> Function() fetch,
   T Function(dynamic json)? fromJsonT,
@@ -130,15 +141,19 @@ Future<ResolveResult> resolve(ResolveTask resolveTask) async {
 }
 
 Future<String> createTask(CreateTask createTask) async {
-  return _parse<String>(
+  final result = await _parse<String>(
       () => _client.dio.post("api/v1/tasks", data: createTask),
       (data) => data as String);
+  _notifyTaskChanged();
+  return result;
 }
 
 Future<List<String>> createTaskBatch(CreateTaskBatch createTaskBatch) async {
-  return _parse<List<String>>(
+  final result = await _parse<List<String>>(
       () => _client.dio.post("api/v1/tasks/batch", data: createTaskBatch),
       (data) => (data as List).map((e) => e as String).toList());
+  _notifyTaskChanged();
+  return result;
 }
 
 Future<void> patchTask(String id, ResolveTask patchTask) async {
@@ -154,41 +169,47 @@ Future<List<Task>> getTasks(List<Status> statuses) async {
 }
 
 Future<void> pauseTask(String id) async {
-  return _parse(() => _client.dio.put("api/v1/tasks/$id/pause"), null);
+  await _parse(() => _client.dio.put("api/v1/tasks/$id/pause"), null);
+  _notifyTaskChanged();
 }
 
 Future<void> continueTask(String id) async {
-  return _parse(() => _client.dio.put("api/v1/tasks/$id/continue"), null);
+  await _parse(() => _client.dio.put("api/v1/tasks/$id/continue"), null);
+  _notifyTaskChanged();
 }
 
 Future<void> pauseAllTasks(List<String>? ids) async {
-  return _parse(
+  await _parse(
       () => _client.dio.put("api/v1/tasks/pause", queryParameters: {
             "id": ids,
           }),
       null);
+  _notifyTaskChanged();
 }
 
 Future<void> continueAllTasks(List<String>? ids) async {
-  return _parse(
+  await _parse(
       () => _client.dio.put("api/v1/tasks/continue", queryParameters: {
             "id": ids,
           }),
       null);
+  _notifyTaskChanged();
 }
 
 Future<void> deleteTask(String id, bool force) async {
-  return _parse(
+  await _parse(
       () => _client.dio.delete("api/v1/tasks/$id?force=$force"), null);
+  _notifyTaskChanged();
 }
 
 Future<void> deleteTasks(List<String>? ids, bool force) async {
-  return _parse(
+  await _parse(
       () => _client.dio.delete("api/v1/tasks", queryParameters: {
             "id": ids,
             "force": force,
           }),
       null);
+  _notifyTaskChanged();
 }
 
 Future<DownloaderConfig> getConfig() async {

ui/flutter/lib/api/model/downloader_config.dart

@@ -113,6 +113,7 @@ class ExtraConfig {
   bool notifyWhenNewVersion;
   bool autoStartTasks;
   bool desktopNotification;
+  bool backgroundLocationKeepAlive;
   List<DownloadCategory> downloadCategories;
 
   ExtraConfigBt bt = ExtraConfigBt();
@@ -127,6 +128,7 @@ class ExtraConfig {
     this.notifyWhenNewVersion = true,
     this.autoStartTasks = false,
     this.desktopNotification = true,
+    this.backgroundLocationKeepAlive = false,
     this.downloadCategories = const [],
   });
 

ui/flutter/lib/api/model/downloader_config.g.dart

@@ -111,6 +111,8 @@ ExtraConfig _$ExtraConfigFromJson(Map<String, dynamic> json) => ExtraConfig(
       notifyWhenNewVersion: json['notifyWhenNewVersion'] as bool? ?? true,
       autoStartTasks: json['autoStartTasks'] as bool? ?? false,
       desktopNotification: json['desktopNotification'] as bool? ?? true,
+      backgroundLocationKeepAlive:
+          json['backgroundLocationKeepAlive'] as bool? ?? false,
       downloadCategories: (json['downloadCategories'] as List<dynamic>?)
               ?.map((e) => DownloadCategory.fromJson(e as Map<String, dynamic>))
               .toList() ??
@@ -130,6 +132,7 @@ Map<String, dynamic> _$ExtraConfigToJson(ExtraConfig instance) =>
       'notifyWhenNewVersion': instance.notifyWhenNewVersion,
       'autoStartTasks': instance.autoStartTasks,
       'desktopNotification': instance.desktopNotification,
+      'backgroundLocationKeepAlive': instance.backgroundLocationKeepAlive,
       'downloadCategories':
           instance.downloadCategories.map((e) => e.toJson()).toList(),
       'bt': instance.bt.toJson(),

ui/flutter/lib/app/modules/setting/views/setting_view.dart

@@ -32,6 +32,8 @@ import '../../../views/outlined_button_loading.dart';
 import '../../../views/text_button_loading.dart';
 import '../../app/controllers/app_controller.dart';
 import '../controllers/setting_controller.dart';
+import '../../../services/location_keep_alive.dart';
+import '../../../services/location_keep_alive_coordinator.dart';
 
 const _padding = SizedBox(height: 10);
 final _divider = const Divider().paddingOnly(left: 10, right: 10);
@@ -521,6 +523,44 @@ class SettingView extends GetView<SettingController> {
             );
           });
 
+    final buildBackgroundLocationKeepAlive = !Platform.isIOS
+        ? () => const SizedBox.shrink()
+        : _buildConfigItem(
+            'backgroundLocationKeepAlive',
+            () {
+              return appController
+                      .downloaderConfig.value.extra.backgroundLocationKeepAlive
+                  ? 'on'.tr
+                  : 'off'.tr;
+            },
+            (Key key) {
+              return Container(
+                alignment: Alignment.centerLeft,
+                child: Switch(
+                  value: appController
+                      .downloaderConfig.value.extra.backgroundLocationKeepAlive,
+                  onChanged: (bool value) async {
+                    if (value) {
+                      final authorized =
+                        await LocationKeepAlive.requestPermission();
+
+                    if (!authorized) {
+                      return;
+                      }
+                    }
+
+                    appController.downloaderConfig.update((val) {
+                      val!.extra.backgroundLocationKeepAlive = value;
+                    });
+
+                    await debounceSave();
+                    await Get.find<LocationKeepAliveCoordinator>().reconcile();
+                  },
+                ),
+              );
+            },
+          );
+
     // http config items start
     final httpConfig = downloaderCfg.value.protocolConfig.http;
     final buildHttpUa =
@@ -1748,6 +1788,7 @@ class SettingView extends GetView<SettingController> {
                             buildAutoStartup(),
                             buildMenubarMode(),
                             buildDesktopNotification(),
+                            buildBackgroundLocationKeepAlive(),
                           ]),
                         )),
                         Text('archives'.tr),

ui/flutter/lib/app/modules/task/controllers/task_list_controller.dart

@@ -50,4 +50,5 @@ abstract class TaskListController extends GetxController {
     tasks.sort(compare);
     this.tasks.value = tasks;
   }
+
 }

ui/flutter/lib/app/services/location_keep_alive.dart

@@ -0,0 +1,32 @@
+//for ios
+import 'dart:io';
+
+import 'package:flutter/services.dart';
+
+class LocationKeepAlive {
+  static const _channel = MethodChannel('gopeed/location_keep_alive');
+
+  static Future<bool> requestPermission() async {
+    if (!Platform.isIOS) return false;
+
+    try {
+      final result = await _channel.invokeMethod<bool>('requestPermission');
+
+      return result ?? false;
+    } catch (_) {
+      return false;
+    }
+  }
+
+  static Future<void> start() async {
+    if (!Platform.isIOS) return;
+
+    await _channel.invokeMethod('start');
+  }
+
+  static Future<void> stop() async {
+    if (!Platform.isIOS) return;
+
+    await _channel.invokeMethod('stop');
+  }
+}

ui/flutter/lib/app/services/location_keep_alive_coordinator.dart

@@ -0,0 +1,75 @@
+import 'dart:async';
+import 'package:get/get.dart';
+import '../../../api/api.dart' as api;
+import '../../../api/model/task.dart';
+import '../modules/app/controllers/app_controller.dart';
+import 'location_keep_alive.dart';
+
+class LocationKeepAliveCoordinator extends GetxService {
+  Timer? _pollTimer;
+  bool _reconciling = false;
+
+  /// Overridable for testing, defaults to reading from AppController.
+  bool Function() keepAliveEnabledProvider = () => Get.find<AppController>()
+      .downloaderConfig
+      .value
+      .extra
+      .backgroundLocationKeepAlive;
+
+  /// Overridable for testing so polling tests don't need to wait 10s.
+  Duration pollInterval = const Duration(seconds: 10);
+
+  bool get _keepAliveEnabled => keepAliveEnabledProvider();
+
+  @override
+  void onInit() {
+    super.onInit();
+    api.setTaskChangedListener(() {
+      reconcile();
+    });
+  }
+
+  Future<int> _fetchGlobalRunningCount() async {
+    try {
+      final tasks = await api.getTasks([Status.running]);
+      return tasks.length;
+    } catch (_) {
+      return -1;
+    }
+  }
+
+  Future<void> reconcile() async {
+    if (_reconciling) return;
+    _reconciling = true;
+    try {
+      if (!_keepAliveEnabled) {
+        await LocationKeepAlive.stop();
+        return;
+      }
+      final count = await _fetchGlobalRunningCount();
+      if (count < 0) return;
+      if (count > 0) {
+        await LocationKeepAlive.start();
+      } else {
+        await LocationKeepAlive.stop();
+      }
+    } finally {
+      _reconciling = false;
+    }
+  }
+
+  void startPolling() {
+    _pollTimer?.cancel();
+    _pollTimer = Timer.periodic(pollInterval, (_) => reconcile());
+  }
+
+  void stopPolling() {
+    _pollTimer?.cancel();
+  }
+
+  @override
+  void onClose() {
+    stopPolling();
+    super.onClose();
+  }
+}

ui/flutter/lib/i18n/langs/en_us.dart

@@ -226,6 +226,7 @@ const enUS = {
     'ed2kServerMetHint': 'Server.met URL or ed2k serverlist link, one per line',
     'ed2kNodesDatHint': 'nodes.dat path or URL, one per line',
     'desktopNotification': 'Desktop Notifications',
+    'backgroundLocationKeepAlive': 'Background Download Keep Alive',
     'notificationTaskDone': 'Task completed',
     'notificationTaskError': 'Task error',
   },

ui/flutter/lib/i18n/langs/zh_cn.dart

@@ -221,6 +221,7 @@ const zhCN = {
     'ed2kServerMetHint': '请输入 Server.met 地址或 ed2k 服务器列表链接，每行一条',
     'ed2kNodesDatHint': '请输入 nodes.dat 本地路径或 URL，每行一条',
     'desktopNotification': '桌面通知',
+    'backgroundLocationKeepAlive': '常驻后台',
     'notificationTaskDone': '任务完成',
     'notificationTaskError': '任务失败',
   }

ui/flutter/lib/main.dart

@@ -22,6 +22,7 @@ import 'util/package_info.dart';
 import 'util/scheme_register/scheme_register.dart';
 import 'util/updater.dart';
 import 'util/util.dart';
+import 'app/services/location_keep_alive_coordinator.dart';
 
 class StartupArgs {
   static const flagHidden = "hidden";
@@ -135,6 +136,17 @@ Future<void> init(StartupArgs args) async {
       logger.w("auto-start tasks fail", e);
     }
   }
+  
+  // iOS location keep-alive coordinator
+  if (Util.isIOS()) {
+    try {
+      await Get.putAsync(() async => LocationKeepAliveCoordinator());
+      await Get.find<LocationKeepAliveCoordinator>().reconcile();
+      Get.find<LocationKeepAliveCoordinator>().startPolling();
+    } catch (e) {
+      logger.e("location keep-alive coordinator init fail", e);
+    }
+  }
 
   () async {
     if (Util.isDesktop()) {