[mob][photos] Require Authentication on App Reopen from Guest View (#3131)

This PR introduces a security enhancement that requires authentication
when the app is reopened after being closed while in guest view.

mobile/lib/main.dart

@@ -112,7 +112,8 @@ Future<void> _runInForeground(AdaptiveThemeMode? savedThemeMode) async {
         builder: (args) =>
             EnteApp(_runBackgroundTask, _killBGTask, locale, savedThemeMode),
         lockScreen: const LockScreen(),
-        enabled: await Configuration.instance.shouldShowLockScreen(),
+        enabled: await Configuration.instance.shouldShowLockScreen() ||
+            localSettings.isOnGuestView(),
         locale: locale,
         lightTheme: lightThemeData,
         darkTheme: darkThemeData,

mobile/lib/ui/tools/lock_screen.dart

@@ -9,6 +9,7 @@ import 'package:logging/logging.dart';
 import "package:photos/core/configuration.dart";
 import "package:photos/generated/l10n.dart";
 import "package:photos/l10n/l10n.dart";
+import "package:photos/service_locator.dart";
 import "package:photos/services/user_service.dart";
 import "package:photos/theme/ente_theme.dart";
 import "package:photos/ui/components/buttons/icon_button_widget.dart";
@@ -346,6 +347,7 @@ class _LockScreenState extends State<LockScreen>
           lockedTimeInSeconds = 15;
           isTimerRunning = false;
         });
+        await localSettings.setOnGuestView(false);
       } else {
         if (!_hasPlacedAppInBackground) {
           if (_lockscreenSetting.getInvalidAttemptCount() > 4 &&

mobile/lib/ui/viewer/actions/file_selection_actions_widget.dart

@@ -21,6 +21,7 @@ import 'package:photos/models/gallery_type.dart';
 import "package:photos/models/metadata/common_keys.dart";
 import "package:photos/models/ml/face/person.dart";
 import 'package:photos/models/selected_files.dart';
+import "package:photos/service_locator.dart";
 import 'package:photos/services/collections_service.dart';
 import 'package:photos/services/hidden_service.dart';
 import 'package:photos/services/machine_learning/face_ml/feedback/cluster_feedback.dart';
@@ -581,6 +582,7 @@ class _FileSelectionActionsWidgetState
           "guest_view",
         ),
       );
+      await localSettings.setOnGuestView(true);
       routeToPage(context, page, forceCustomPageRoute: true).ignore();
       WidgetsBinding.instance.addPostFrameCallback((_) {
         Bus.instance.fire(GuestViewEvent(true, false));

mobile/lib/ui/viewer/file/detail_page.dart

@@ -15,6 +15,7 @@ import "package:photos/generated/l10n.dart";
 import "package:photos/models/file/extensions/file_props.dart";
 import 'package:photos/models/file/file.dart';
 import "package:photos/models/file/file_type.dart";
+import "package:photos/service_locator.dart";
 import "package:photos/services/local_authentication_service.dart";
 import "package:photos/ui/common/fast_scroll_physics.dart";
 import 'package:photos/ui/tools/editor/image_editor_page.dart';
@@ -156,6 +157,7 @@ class _DetailPageState extends State<DetailPage> {
           final authenticated = await _requestAuthentication();
           if (authenticated) {
             Bus.instance.fire(GuestViewEvent(false, false));
+            await localSettings.setOnGuestView(false);
           }
         }
       },

mobile/lib/ui/viewer/file/file_app_bar.dart

@@ -475,6 +475,7 @@ class FileAppBarState extends State<FileAppBar> {
   Future<void> _onTapGuestView() async {
     if (await LocalAuthentication().isDeviceSupported()) {
       Bus.instance.fire(GuestViewEvent(true, true));
+      await localSettings.setOnGuestView(true);
     } else {
       await showErrorDialog(
         context,
@@ -492,6 +493,7 @@ class FileAppBarState extends State<FileAppBar> {
     );
     if (hasAuthenticated) {
       Bus.instance.fire(GuestViewEvent(false, false));
+      await localSettings.setOnGuestView(false);
     }
   }
 }

mobile/lib/utils/local_settings.dart

@@ -15,6 +15,7 @@ class LocalSettings {
   static const kEnableMultiplePart = "ls.enable_multiple_part";
   static const kRateUsPromptThreshold = 2;
   static const shouldLoopVideoKey = "video.should_loop";
+  static const onGuestViewKey = "on_guest_view";
 
   final SharedPreferences _prefs;
 
@@ -91,4 +92,12 @@ class LocalSettings {
   bool shouldLoopVideo() {
     return _prefs.getBool(shouldLoopVideoKey) ?? true;
   }
+
+  Future<void> setOnGuestView(bool value) {
+    return _prefs.setBool(onGuestViewKey, value);
+  }
+
+  bool isOnGuestView() {
+    return _prefs.getBool(onGuestViewKey) ?? false;
+  }
 }