feat(push_notifications): issue-660, fix: issue-908

lib/features/menu/presentation/notification_settings_user_message.dart

@@ -0,0 +1,42 @@
+import 'package:dio/dio.dart';
+
+const notificationSettingsSaveFailedMessage =
+    'Не удалось сохранить настройки уведомлений';
+
+
+String notificationSettingsUpdateAlertMessage(Object error) {
+  final validationMessage = _validationMessage(error);
+  if (validationMessage != null) return validationMessage;
+  return notificationSettingsSaveFailedMessage;
+}
+
+String? _validationMessage(Object error) {
+  if (error is! DioException || error.response?.statusCode != 422) return null;
+
+  final data = error.response?.data;
+  if (data is! Map) return null;
+
+  final errors = data['errors'];
+  if (errors is Map) {
+    for (final value in errors.values) {
+      final text = _firstErrorText(value);
+      if (text != null) return text;
+    }
+  }
+
+  final message = data['message'];
+  if (message is String && message.trim().isNotEmpty) return message.trim();
+  return null;
+}
+
+String? _firstErrorText(Object? value) {
+  if (value is List) {
+    for (final item in value) {
+      final text = item.toString().trim();
+      if (text.isNotEmpty) return text;
+    }
+    return null;
+  }
+  if (value is String && value.trim().isNotEmpty) return value.trim();
+  return null;
+}