fix(dashboard): exit edit mode when navigating away (#1037)

lib/page/dashboard/providers/dashboard_edit_mode_provider.dart

@@ -0,0 +1,111 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:privacy_gui/page/dashboard/models/usp_layout_preferences.dart';
+import 'package:privacy_gui/page/dashboard/providers/usp_layout_controller.dart';
+import 'package:privacy_gui/page/dashboard/providers/usp_layout_preferences_provider.dart';
+
+/// Manages dashboard edit mode state and layout snapshots for revert on cancel.
+///
+/// This provider centralizes edit mode state so it can be accessed from route
+/// guards (onExit) to handle navigation away during edit mode.
+final dashboardEditModeProvider =
+    NotifierProvider<DashboardEditModeNotifier, DashboardEditState>(
+  DashboardEditModeNotifier.new,
+);
+
+class DashboardEditState {
+  final bool isEditing;
+  final List<Map<String, dynamic>>? layoutSnapshot;
+  final UspLayoutPreferences? prefsSnapshot;
+
+  const DashboardEditState({
+    this.isEditing = false,
+    this.layoutSnapshot,
+    this.prefsSnapshot,
+  });
+
+  DashboardEditState copyWith({
+    bool? isEditing,
+    List<Map<String, dynamic>>? layoutSnapshot,
+    UspLayoutPreferences? prefsSnapshot,
+    bool clearSnapshots = false,
+  }) {
+    return DashboardEditState(
+      isEditing: isEditing ?? this.isEditing,
+      layoutSnapshot:
+          clearSnapshots ? null : (layoutSnapshot ?? this.layoutSnapshot),
+      prefsSnapshot:
+          clearSnapshots ? null : (prefsSnapshot ?? this.prefsSnapshot),
+    );
+  }
+}
+
+class DashboardEditModeNotifier extends Notifier<DashboardEditState> {
+  @override
+  DashboardEditState build() => const DashboardEditState();
+
+  /// Enter edit mode and capture snapshots for potential revert.
+  Future<void> enterEditMode() async {
+    // Re-entrant guard: a double-tap or gesture race must not re-capture the
+    // already-modified grid as the "original" snapshot.
+    if (state.isEditing) return;
+
+    // Claim the edit slot BEFORE the await so a route guard (onExit) firing in
+    // the async gap always observes isEditing=true and reverts correctly.
+    state = const DashboardEditState(isEditing: true);
+
+    await ref.read(uspLayoutPreferencesProvider.notifier).initialized;
+
+    // If we were cancelled during the await (e.g. navigation away), bail out
+    // instead of resuming and stranding the controller in edit mode.
+    if (!state.isEditing) return;
+
+    final controller = ref.read(uspSliverDashboardControllerProvider);
+    final layoutSnapshot = controller.exportLayout();
+    final prefsSnapshot = ref.read(uspLayoutPreferencesProvider);
+
+    state = DashboardEditState(
+      isEditing: true,
+      layoutSnapshot: layoutSnapshot,
+      prefsSnapshot: prefsSnapshot,
+    );
+
+    controller.setEditMode(true);
+  }
+
+  /// Exit edit mode, keeping the current layout (changes are already persisted
+  /// on each drag/resize, so committing is just clearing the edit flag).
+  Future<void> commitEditMode() => _exitEditMode(revert: false);
+
+  /// Exit edit mode and revert the layout/prefs to the pre-edit snapshots
+  /// captured in [enterEditMode].
+  Future<void> cancelEditMode() => _exitEditMode(revert: true);
+
+  /// Shared exit path for [commitEditMode] / [cancelEditMode].
+  ///
+  /// The edit flag and snapshots are always cleared in the `finally` block so
+  /// that a failure in [DashboardController.saveLayout] /
+  /// [UspLayoutPreferencesNotifier.restoreSnapshot] can never leave the
+  /// dashboard stuck in edit mode with stale state.
+  Future<void> _exitEditMode({required bool revert}) async {
+    final controller = ref.read(uspSliverDashboardControllerProvider);
+
+    try {
+      if (revert) {
+        if (state.layoutSnapshot != null) {
+          controller.importLayout(state.layoutSnapshot!);
+          await ref
+              .read(uspSliverDashboardControllerProvider.notifier)
+              .saveLayout();
+        }
+        if (state.prefsSnapshot != null) {
+          await ref
+              .read(uspLayoutPreferencesProvider.notifier)
+              .restoreSnapshot(state.prefsSnapshot!);
+        }
+      }
+    } finally {
+      controller.setEditMode(false);
+      state = const DashboardEditState();
+    }
+  }
+}

lib/page/dashboard/views/usp_sliver_dashboard_view.dart

@@ -6,7 +6,7 @@ import 'package:privacy_gui/page/dashboard/views/components/effects/jiggle_shake
 import 'package:privacy_gui/page/dashboard/factories/usp_widget_factory.dart';
 import 'package:privacy_gui/constants/pref_key.dart';
 import 'package:privacy_gui/page/dashboard/models/usp_dashboard_preset.dart';
-import 'package:privacy_gui/page/dashboard/models/usp_layout_preferences.dart';
+import 'package:privacy_gui/page/dashboard/providers/dashboard_edit_mode_provider.dart';
 import 'package:privacy_gui/page/dashboard/models/package_widget_template.dart';
 import 'package:privacy_gui/page/dashboard/providers/package_widget_loader.dart';
 import 'package:privacy_gui/page/dashboard/widgets/package_widget_renderer.dart';
@@ -42,9 +42,6 @@ class UspSliverDashboardView extends ConsumerStatefulWidget {
 
 class _UspSliverDashboardViewState
     extends ConsumerState<UspSliverDashboardView> {
-  bool _isEditMode = false;
-  List<dynamic>? _initialLayoutSnapshot;
-  UspLayoutPreferences? _initialPrefsSnapshot;
   bool _presetDialogShown = false;
 
   @override
@@ -112,45 +109,15 @@ class _UspSliverDashboardViewState
   }
 
   void _enterEditMode() async {
-    // Ensure preferences have been loaded from SharedPreferences before
-    // capturing the snapshot. Without this, the snapshot may capture the
-    // default state (preset = null) if _loadFromPrefs hasn't completed yet.
-    await ref.read(uspLayoutPreferencesProvider.notifier).initialized;
-
-    final controller = ref.read(uspSliverDashboardControllerProvider);
-    _initialLayoutSnapshot = controller.exportLayout();
-    _initialPrefsSnapshot = ref.read(uspLayoutPreferencesProvider);
-
-    if (!mounted) return;
-    setState(() {
-      _isEditMode = true;
-    });
-    controller.setEditMode(true);
+    await ref.read(dashboardEditModeProvider.notifier).enterEditMode();
   }
 
-  void _exitEditMode({bool save = true}) async {
-    final controller = ref.read(uspSliverDashboardControllerProvider);
-
-    if (!save) {
-      if (_initialLayoutSnapshot != null) {
-        controller.importLayout(_initialLayoutSnapshot!);
-        await ref
-            .read(uspSliverDashboardControllerProvider.notifier)
-            .saveLayout();
-      }
-      if (_initialPrefsSnapshot != null) {
-        await ref
-            .read(uspLayoutPreferencesProvider.notifier)
-            .restoreSnapshot(_initialPrefsSnapshot!);
-      }
-    }
+  void _commitEditMode() async {
+    await ref.read(dashboardEditModeProvider.notifier).commitEditMode();
+  }
 
-    setState(() {
-      _isEditMode = false;
-      _initialLayoutSnapshot = null;
-      _initialPrefsSnapshot = null;
-    });
-    controller.setEditMode(false);
+  void _cancelEditMode() async {
+    await ref.read(dashboardEditModeProvider.notifier).cancelEditMode();
   }
 
   @override
@@ -205,14 +172,15 @@ class _UspSliverDashboardViewState
 
   Widget _buildHeader(BuildContext context) {
     final isRemoteMode = GlobalConfig.remote.isActive;
+    final isEditMode = ref.watch(dashboardEditModeProvider).isEditing;
 
     return Row(
       mainAxisAlignment: MainAxisAlignment.spaceBetween,
       children: [
         AppText.headlineSmall(loc(context).uspDashboard),
         Row(
           children: [
-            if (_isEditMode) ...[
+            if (isEditMode) ...[
               AppIconButton(
                 icon: AppIcon.font(Icons.auto_fix_high),
                 onTap: () {
@@ -240,12 +208,12 @@ class _UspSliverDashboardViewState
               AppGap.sm(),
               AppIconButton(
                 icon: AppIcon.font(Icons.close),
-                onTap: () => _exitEditMode(save: false),
+                onTap: _cancelEditMode,
               ),
               AppGap.sm(),
               AppIconButton(
                 icon: AppIcon.font(Icons.check),
-                onTap: () => _exitEditMode(save: true),
+                onTap: _commitEditMode,
               ),
             ] else ...[
               AppIconButton(
@@ -339,6 +307,7 @@ class _UspSliverDashboardViewState
   Widget _buildSliverDashboard(BuildContext context) {
     final controller = ref.watch(uspSliverDashboardControllerProvider);
     final factory = ref.watch(uspWidgetFactoryProvider);
+    final isEditMode = ref.watch(dashboardEditModeProvider).isEditing;
     final uiKitColumns = context.currentMaxColumns;
     final scrollController = ScrollController();
 
@@ -360,18 +329,18 @@ class _UspSliverDashboardViewState
         controller: controller,
         scrollController: scrollController,
         itemBuilder: (context, item) {
-          return _buildItemWidget(context, item, _isEditMode, factory);
+          return _buildItemWidget(context, item, isEditMode, factory);
         },
         slotAspectRatio: ratio,
         mainAxisSpacing: AppSpacing.lg,
         crossAxisSpacing: AppSpacing.lg,
         padding: EdgeInsets.symmetric(horizontal: pageMargin),
-        gridStyle: _isEditMode ? editModeGridStyle : null,
+        gridStyle: isEditMode ? editModeGridStyle : null,
         onItemResizeEnd: (item) {
           _handleResizeEnd(context, item);
         },
         // Drag-to-trash for widget removal in edit mode.
-        trashBuilder: !_isEditMode
+        trashBuilder: !isEditMode
             ? null
             : (context, isHovered, isActive, activeItemId) {
                 return _buildTrashZone(context, isHovered, isActive);
@@ -388,13 +357,13 @@ class _UspSliverDashboardViewState
               padding: EdgeInsets.symmetric(horizontal: pageMargin),
               sliver: SliverDashboard(
                 itemBuilder: (context, item) {
-                  return _buildItemWidget(context, item, _isEditMode, factory);
+                  return _buildItemWidget(context, item, isEditMode, factory);
                 },
                 slotAspectRatio: ratio,
                 mainAxisSpacing: AppSpacing.lg,
                 crossAxisSpacing: AppSpacing.lg,
                 breakpoints: {0: uiKitColumns},
-                gridStyle: _isEditMode ? editModeGridStyle : null,
+                gridStyle: isEditMode ? editModeGridStyle : null,
               ),
             ),
             const SliverToBoxAdapter(
@@ -542,15 +511,11 @@ class _UspSliverDashboardViewState
       ),
     );
 
-    if ((result == 'reset' ||
-            result == 'toggle_off' ||
-            result == 'preset_changed') &&
-        mounted) {
-      setState(() {
-        _isEditMode = false;
-        _initialLayoutSnapshot = null;
-        _initialPrefsSnapshot = null;
-      });
+    if ((result == 'reset' || result == 'preset_changed') && mounted) {
+      // Commit (keep) the change — the settings panel already applied the
+      // reset/preset directly to the controller and prefs, so exiting must
+      // preserve it, not revert to the pre-edit snapshot.
+      await ref.read(dashboardEditModeProvider.notifier).commitEditMode();
     }
   }
 

lib/route/route_usp_dashboard.dart

@@ -19,6 +19,32 @@ final uspDashboardRoute = ShellRoute(
         });
         return const UspDashboardView();
       },
+      onExit: (context, state) async {
+        // Cancel edit mode when navigating away from dashboard (e.g., tab
+        // switch), reverting to the pre-edit snapshot.
+        //
+        // Intentional silent-discard policy: unlike the enableDirtyCheck routes
+        // below, the dashboard does NOT prompt with showUnsavedAlert. Layout
+        // edits are persisted on every drag/resize, so "cancel" means restoring
+        // the snapshot captured on edit-mode entry — there is no unsaved buffer
+        // to warn about, and a confirmation dialog on every tab switch would be
+        // noise. See #1037.
+        final container = ProviderScope.containerOf(context);
+        final editState = container.read(dashboardEditModeProvider);
+        if (editState.isEditing) {
+          try {
+            await container
+                .read(dashboardEditModeProvider.notifier)
+                .cancelEditMode();
+          } catch (e, s) {
+            // Never block navigation on a revert failure; cancelEditMode resets
+            // its own state in a finally block, so edit mode won't be stranded.
+            logger.e('[Route]: dashboard cancelEditMode failed on exit',
+                error: e, stackTrace: s);
+          }
+        }
+        return true;
+      },
     ),
     LinksysRoute(
       name: RouteNamed.uspMenu,

lib/route/router_provider.dart

@@ -24,6 +24,7 @@ import 'navigation_extra.dart';
 
 // USP dashboard imports
 import 'package:privacy_gui/page/_shared/providers/usp_bars_visible_provider.dart';
+import 'package:privacy_gui/page/dashboard/providers/dashboard_edit_mode_provider.dart';
 import 'package:privacy_gui/page/dashboard/views/usp_dashboard_view.dart';
 import 'package:privacy_gui/page/menu/views/usp_menu_view.dart';
 import 'package:privacy_gui/page/support/views/usp_support_view.dart';