feat(ui): unify child surfaces and show web task creation in a modal (#1633)

ui/flutter/lib/app/application/app_deep_link_controller.dart

@@ -13,9 +13,7 @@ import '../../api/model/install_extension.dart';
 import '../../api/model/request.dart';
 import '../../core/entry/app_startup_options.dart';
 import '../../core/utils/content_uri_resolver.dart';
-import '../../core/window/app_window_launcher.dart';
 import '../../features/extensions/application/pending_extension_install.dart';
-import '../../features/tasks/application/pending_create_task.dart';
 import '../../util/util.dart';
 import '../router/app_router.dart';
 import 'app_runtime_controller.dart';
@@ -118,18 +116,7 @@ class AppDeepLinkController extends AsyncNotifier<AppDeepLinkState> {
     await _go('/');
   }
 
-  Future<void> _openCreate(CreateTask? createTask) async {
-    if (Util.isDesktop()) {
-      final opened = await AppWindowLauncher.openCreateTaskWindow(createTask: createTask);
-      if (!opened) {
-        ref.read(pendingCreateTaskProvider.notifier).set(createTask);
-        await _go('/create');
-      }
-      return;
-    }
-    ref.read(pendingCreateTaskProvider.notifier).set(createTask);
-    await _go('/create');
-  }
+  Future<void> _openCreate(CreateTask? createTask) => AppRouter.openCreateTask(createTask: createTask);
 
   Future<void> _go(String route) async {
     if (Util.isDesktop()) {

ui/flutter/lib/app/application/app_platform_controller.dart

@@ -14,9 +14,7 @@ import '../../api/api.dart' as api;
 import '../../api/model/downloader_config.dart';
 import '../../core/libgopeed_boot.dart';
 import '../../core/capabilities/app_capabilities.dart';
-import '../../core/window/app_window_launcher.dart';
 import '../../core/window/window_capability_transport.dart';
-import '../../features/tasks/application/pending_create_task.dart';
 import '../../features/tasks/application/pending_update_task.dart';
 import '../../l10n/l10n.dart';
 import '../../util/package_info.dart';
@@ -211,11 +209,7 @@ class AppPlatformController extends AsyncNotifier<AppPlatformState> with WindowL
           await ref.read(gopeedServiceProvider).createTask(createTask);
           return;
         }
-        final opened = await AppWindowLauncher.openCreateTaskWindow(createTask: createTask);
-        if (!opened) {
-          ref.read(pendingCreateTaskProvider.notifier).set(createTask);
-          await _go('/create');
-        }
+        await AppRouter.openCreateTask(createTask: createTask);
       },
       onForward: ({required path, required method, data, query}) {
         return api.forward(path, method: method, data: data, queryParameters: query);
@@ -348,10 +342,7 @@ class AppPlatformController extends AsyncNotifier<AppPlatformState> with WindowL
 
   Future<void> _openCreateTask() async {
     await _showMainWindow();
-    final opened = await AppWindowLauncher.openCreateTaskWindow();
-    if (!opened) {
-      _go('/create');
-    }
+    await AppRouter.openCreateTask();
   }
 
   Future<void> _go(String route) async {

ui/flutter/lib/app/child_window_app.dart

@@ -1,13 +1,12 @@
 import 'package:flutter/widgets.dart';
 import 'package:shadcn_flutter/shadcn_flutter.dart' as shad;
 
-import '../api/model/create_task.dart';
 import '../app/application/app_appearance_controller.dart';
 import '../core/window/app_window_bootstrap.dart';
 import '../core/window/app_window_frame.dart';
 import '../core/window/app_window_payload.dart';
 import '../core/window/window_capability_transport.dart';
-import '../features/tasks/presentation/pages/create_task_window_page.dart';
+import 'router/app_window_content.dart';
 import '../l10n/l10n.dart';
 import '../shared/theme/app_component_themes.dart';
 import '../shared/theme/app_theme.dart';
@@ -82,10 +81,7 @@ class _ChildWindowAppState extends State<ChildWindowApp> with WidgetsBindingObse
 
   Widget _buildPage(BuildContext context) {
     return switch (widget.payload.type) {
-      AppWindowType.createTask => CreateTaskWindowPage(
-        windowController: widget.session.controller,
-        initialTask: widget.payload.createTask == null ? null : CreateTask.fromJson(widget.payload.createTask!),
-      ),
+      AppWindowType.createTask => AppWindowContent.build(widget.payload, windowController: widget.session.controller),
       _ => shad.Scaffold(child: Center(child: Text(context.l10n.unsupportedWindowPayload))),
     };
   }

ui/flutter/lib/app/router/app_router.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';
 import 'package:go_router/go_router.dart';
@@ -11,7 +13,13 @@ import '../../features/auth/application/web_auth_controller.dart';
 import '../../features/auth/presentation/pages/login_page.dart';
 import '../../features/home/presentation/pages/home_page.dart';
 import '../../features/settings/presentation/pages/settings_page.dart';
-import '../../features/tasks/presentation/pages/create_task_window_page.dart';
+import '../../api/model/create_task.dart';
+import '../../core/window/app_window_chrome.dart';
+import '../../core/window/app_window_launcher.dart';
+import '../../core/window/app_window_payload.dart';
+import '../../features/tasks/application/pending_create_task.dart';
+import 'app_window_content.dart';
+import 'app_window_page.dart';
 import '../../features/tasks/domain/task_record.dart';
 import '../../features/tasks/presentation/pages/task_details_page.dart';
 import '../../features/tasks/presentation/pages/task_files_page.dart';
@@ -22,6 +30,37 @@ import 'runtime_page.dart';
 class AppRouter {
   static final GlobalKey<NavigatorState> rootNavigatorKey = GlobalKey<NavigatorState>();
 
+  static bool get _isMobile =>
+      !kIsWeb && (defaultTargetPlatform == TargetPlatform.android || defaultTargetPlatform == TargetPlatform.iOS);
+
+  static Future<void> openCreateTask({CreateTask? createTask}) =>
+      openWindow(AppWindowPayload.createTask(createTask: createTask?.toJson()));
+
+  /// Opens a desktop child window, a Web modal, or a native mobile page.
+  /// Callers never need to choose a presentation or implement a fallback.
+  static Future<void> openWindow(AppWindowPayload payload) async {
+    final location = AppWindowContent.location(payload.type);
+    if (AppWindowChrome.isDesktopWindow && await AppWindowLauncher.open(payload)) return;
+    final context = rootNavigatorKey.currentContext;
+    if (context == null || !context.mounted) return;
+    final router = GoRouter.of(context);
+    if (router.state.uri.path == location) {
+      // Native share intents may arrive while the creation page is already open.
+      if (payload.type == AppWindowType.createTask && payload.createTask != null) {
+        ProviderScope.containerOf(
+          context,
+          listen: false,
+        ).read(pendingCreateTaskProvider.notifier).set(CreateTask.fromJson(payload.createTask!));
+      }
+      return;
+    }
+    if (_isMobile) {
+      router.go(location, extra: payload.toRaw());
+    } else {
+      unawaited(router.push<void>(location, extra: payload.toRaw()));
+    }
+  }
+
   static void showDownloadingTasks() {
     final context = rootNavigatorKey.currentContext;
     if (context == null || !context.mounted) return;
@@ -31,8 +70,7 @@ class AppRouter {
 
   static GoRouter build(WebAuthController webAuthController) {
     // Keep desktop and web sections as peers; native mobile retains home below them.
-    final isMobile =
-        !kIsWeb && (defaultTargetPlatform == TargetPlatform.android || defaultTargetPlatform == TargetPlatform.iOS);
+    final isMobile = _isMobile;
     final sectionRoutes = [
       GoRoute(
         path: isMobile ? 'extensions' : '/extensions',
@@ -83,7 +121,33 @@ class AppRouter {
               path: '/',
               builder: _runtimePage((context, state) => const HomePage()),
               routes: [
-                GoRoute(path: 'create', builder: _runtimePage((context, state) => const CreateTaskWindowPage())),
+                GoRoute(
+                  path: 'create',
+                  parentNavigatorKey: rootNavigatorKey,
+                  pageBuilder: (context, state) {
+                    final payload = state.extra is String
+                        ? AppWindowPayload.fromRaw(state.extra! as String)
+                        : AppWindowPayload.createTask();
+                    final child = RuntimePage(
+                      builder: (context) => AppWindowContent.build(
+                        payload,
+                        modal: !isMobile,
+                        onClose: (created) {
+                          if (created) {
+                            showDownloadingTasks();
+                          } else if (context.canPop()) {
+                            context.pop();
+                          } else {
+                            context.go('/');
+                          }
+                        },
+                      ),
+                    );
+                    return isMobile
+                        ? NoTransitionPage<void>(key: state.pageKey, child: child)
+                        : AppWindowPage<void>(key: state.pageKey, child: child);
+                  },
+                ),
                 GoRoute(
                   path: 'tasks/:id',
                   builder: _runtimePage(

ui/flutter/lib/app/router/app_window_content.dart

@@ -0,0 +1,29 @@
+import 'package:desktop_multi_window/desktop_multi_window.dart';
+import 'package:flutter/widgets.dart';
+
+import '../../api/model/create_task.dart';
+import '../../core/window/app_window_payload.dart';
+import '../../features/tasks/presentation/pages/create_task_window_page.dart';
+
+/// Shared destination registry for desktop child engines and in-app windows.
+abstract final class AppWindowContent {
+  static String location(AppWindowType type) => switch (type) {
+    AppWindowType.createTask => '/create',
+    AppWindowType.main => throw ArgumentError.value(type, 'type', 'Expected a child window'),
+  };
+
+  static Widget build(
+    AppWindowPayload payload, {
+    WindowController? windowController,
+    ValueChanged<bool>? onClose,
+    bool modal = false,
+  }) => switch (payload.type) {
+    AppWindowType.createTask => CreateTaskWindowPage(
+      windowController: windowController,
+      initialTask: payload.createTask == null ? null : CreateTask.fromJson(payload.createTask!),
+      onClose: onClose,
+      modal: modal,
+    ),
+    AppWindowType.main => throw ArgumentError.value(payload.type, 'payload.type', 'Expected a child window'),
+  };
+}

ui/flutter/lib/app/router/app_window_page.dart

@@ -0,0 +1,64 @@
+import 'package:shadcn_flutter/shadcn_flutter.dart';
+
+import '../../shared/theme/app_design_tokens.dart';
+import '../../shared/theme/app_palette.dart';
+import '../../core/utils/breakpoints.dart';
+
+/// A routed modal keeps its underlying page mounted and participates in Back.
+class AppWindowPage<T> extends Page<T> {
+  const AppWindowPage({super.key, required this.child, this.preferredSize = AppDesignTokens.childWindowSize});
+
+  final Widget child;
+  final Size preferredSize;
+
+  @override
+  Route<T> createRoute(BuildContext context) => DialogRoute<T>(
+    context: context,
+    settings: this,
+    barrierDismissible: false,
+    barrierColor: Theme.of(context).colorScheme.background.withValues(alpha: 0.6),
+    traversalEdgeBehavior: TraversalEdgeBehavior.closedLoop,
+    alignment: Alignment.center,
+    fullScreen: true,
+    transitionBuilder: (context, animation, secondaryAnimation, child) =>
+        FadeTransition(opacity: animation, child: child),
+    builder: (context) => Padding(
+      padding: EdgeInsets.only(bottom: MediaQuery.viewInsetsOf(context).bottom),
+      child: LayoutBuilder(
+        builder: (context, constraints) {
+          final page = ModalRoute.settingsOf(context)! as AppWindowPage<T>;
+          final palette = AppPalette.of(context);
+          return Padding(
+            padding: EdgeInsets.all(
+              constraints.maxWidth < Breakpoints.mobile ? AppDesignTokens.space12 : AppDesignTokens.space32,
+            ),
+            child: Center(
+              child: ConstrainedBox(
+                constraints: BoxConstraints(maxWidth: page.preferredSize.width, maxHeight: page.preferredSize.height),
+                child: ModalContainer(
+                  key: const ValueKey('app-window-modal'),
+                  padding: EdgeInsets.zero,
+                  filled: true,
+                  fillColor: palette.sideBg,
+                  borderColor: palette.border,
+                  borderRadius: BorderRadius.circular(AppDesignTokens.windowRadius),
+                  clipBehavior: Clip.antiAlias,
+                  child: MediaQuery.removeViewInsets(
+                    context: context,
+                    removeBottom: true,
+                    child: MediaQuery.removePadding(
+                      context: context,
+                      removeTop: true,
+                      removeBottom: true,
+                      child: page.child,
+                    ),
+                  ),
+                ),
+              ),
+            ),
+          );
+        },
+      ),
+    ),
+  );
+}

ui/flutter/lib/app/router/shells/main_shell.dart

@@ -3,7 +3,6 @@ import 'dart:async';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
-import 'package:go_router/go_router.dart';
 
 import '../../../api/model/create_task.dart';
 import '../../application/app_deep_link_controller.dart';
@@ -11,11 +10,10 @@ import '../../application/app_notification_controller.dart';
 import '../../application/app_runtime_controller.dart';
 import '../../application/app_platform_controller.dart';
 import '../../../features/settings/presentation/widgets/app_update_dialog.dart';
-import '../../../features/tasks/application/pending_create_task.dart';
 import '../../../features/tasks/application/pending_update_task.dart';
 import '../../../features/tasks/application/tasks_controller.dart';
 import '../../../features/tasks/presentation/widgets/pending_update_dialog.dart';
-import '../../../core/window/app_window_launcher.dart';
+import '../app_router.dart';
 import '../../../shared/widgets/app_toast.dart';
 
 class MainShell extends ConsumerStatefulWidget {
@@ -124,11 +122,5 @@ class _MainShellState extends ConsumerState<MainShell> {
     }
   }
 
-  Future<void> _openCapturedCreateTask(CreateTask createTask) async {
-    final opened = await AppWindowLauncher.openCreateTaskWindow(createTask: createTask);
-    if (!opened && mounted) {
-      ref.read(pendingCreateTaskProvider.notifier).set(createTask);
-      context.go('/create');
-    }
-  }
+  Future<void> _openCapturedCreateTask(CreateTask createTask) => AppRouter.openCreateTask(createTask: createTask);
 }