feat: Display warning banner on unverified devices

assets/l10n/intl_en.arb

@@ -2786,5 +2786,7 @@
     "placeholders": {
       "seconds": {}
     }
-  }
+  },
+  "oneOfYourDevicesIsNotVerified": "One of your devices is not verified",
+  "noticeChatBackupDeviceVerification": "Note: When you connect all your devices to the chat backup, they are automatically verified."
 }

lib/config/themes.dart

@@ -130,6 +130,9 @@ abstract class FluffyThemes {
           borderRadius: BorderRadius.circular(AppConfig.borderRadius / 2),
         ),
       ),
+      snackBarTheme: const SnackBarThemeData(
+        behavior: SnackBarBehavior.floating,
+      ),
       elevatedButtonTheme: ElevatedButtonThemeData(
         style: ElevatedButton.styleFrom(
           backgroundColor: colorScheme.secondaryContainer,

lib/pages/chat_list/chat_list.dart

@@ -820,6 +820,7 @@ class ChatListController extends State<ChatList>
   bool waitForFirstSync = false;
 
   Future<void> _waitForFirstSync() async {
+    final router = GoRouter.of(context);
     final client = Matrix.of(context).client;
     await client.roomsLoading;
     await client.accountDataLoading;
@@ -840,6 +841,33 @@ class ChatListController extends State<ChatList>
     setState(() {
       waitForFirstSync = true;
     });
+
+    if (client.userDeviceKeys[client.userID!]?.deviceKeys.values
+            .any((device) => !device.verified && !device.blocked) ??
+        false) {
+      late final ScaffoldFeatureController controller;
+      final theme = Theme.of(context);
+      controller = ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(
+          duration: const Duration(seconds: 15),
+          backgroundColor: theme.colorScheme.errorContainer,
+          content: Text(
+            L10n.of(context).oneOfYourDevicesIsNotVerified,
+            style: TextStyle(
+              color: theme.colorScheme.onErrorContainer,
+            ),
+          ),
+          action: SnackBarAction(
+            onPressed: () {
+              controller.close();
+              router.go('/rooms/settings/devices');
+            },
+            textColor: theme.colorScheme.onErrorContainer,
+            label: L10n.of(context).settings,
+          ),
+        ),
+      );
+    }
   }
 
   void cancelAction() {

lib/pages/device_settings/device_settings.dart

@@ -32,6 +32,28 @@ class DevicesSettingsController extends State<DevicesSettings> {
   bool loadingDeletingDevices = false;
   String? errorDeletingDevices;
 
+  bool? chatBackupEnabled;
+
+  @override
+  void initState() {
+    _checkChatBackup();
+    super.initState();
+  }
+
+  void _checkChatBackup() async {
+    final client = Matrix.of(context).client;
+    if (client.encryption?.keyManager.enabled == true) {
+      if (await client.encryption?.keyManager.isCached() == false ||
+          await client.encryption?.crossSigning.isCached() == false ||
+          client.isUnknownSession && !mounted) {
+        setState(() {
+          chatBackupEnabled = false;
+        });
+        return;
+      }
+    }
+  }
+
   void removeDevicesAction(List<Device> devices) async {
     if (await showOkCancelAlertDialog(
           context: context,

lib/pages/device_settings/device_settings_view.dart

@@ -48,6 +48,19 @@ class DevicesSettingsView extends StatelessWidget {
                   return Column(
                     mainAxisSize: MainAxisSize.min,
                     children: [
+                      if (controller.chatBackupEnabled == false)
+                        Padding(
+                          padding: const EdgeInsets.symmetric(horizontal: 8.0),
+                          child: ListTile(
+                            leading: const CircleAvatar(
+                              child: Icon(Icons.info_outlined),
+                            ),
+                            subtitle: Text(
+                              L10n.of(context)
+                                  .noticeChatBackupDeviceVerification,
+                            ),
+                          ),
+                        ),
                       if (controller.thisDevice != null) ...[
                         Container(
                           padding: const EdgeInsets.symmetric(

lib/widgets/fluffy_chat_app.dart

@@ -34,7 +34,10 @@ class FluffyChatApp extends StatelessWidget {
 
   // Router must be outside of build method so that hot reload does not reset
   // the current path.
-  static final GoRouter router = GoRouter(routes: AppRoutes.routes);
+  static final GoRouter router = GoRouter(
+    routes: AppRoutes.routes,
+    debugLogDiagnostics: true,
+  );
 
   @override
   Widget build(BuildContext context) {