added guardian letters with chat and multiple answer functionalities

lib/notification/notification_controller.dart

@@ -5,7 +5,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 
 import '../push/push_message_handler.dart';
-import '../routing/app_routes.dart';
+import '../push/push_target.dart';
 import '../state/app/modules/chat/bloc/chat_bloc.dart';
 import '../widget/debug/debug_tile.dart';
 import '../widget/debug/json_viewer.dart';
@@ -42,18 +42,15 @@ class NotificationController {
     RemoteMessage message,
     BuildContext context,
   ) async {
-    final newsletterId = _extractNewsletterId(message);
-    if (newsletterId != null) {
-      AppRoutes.openNewsletterById(
+    final target = resolvePushTarget(message.data);
+    if (target != null) {
+      NotificationTasks.openPushTarget(
         context,
-        id: newsletterId,
+        target,
         title: message.notification?.title,
       );
     } else {
-      NotificationTasks.navigateToTalk(
-        context,
-        chatToken: _extractChatToken(message),
-      );
+      NotificationTasks.navigateToTalk(context);
     }
     NotificationTasks.updateProviders(context);
     unawaited(NotificationTasks.refreshBadge());
@@ -68,17 +65,4 @@ class NotificationController {
       );
     });
   }
-
-  static String? _extractChatToken(RemoteMessage message) {
-    for (final key in const ['chatToken', 'token', 'roomToken']) {
-      final value = message.data[key];
-      if (value is String && value.isNotEmpty) return value;
-    }
-    return null;
-  }
-
-  static String? _extractNewsletterId(RemoteMessage message) {
-    final value = message.data['newsletterId'];
-    return value is String && value.isNotEmpty ? value : null;
-  }
 }

lib/notification/notification_tasks.dart

@@ -7,10 +7,13 @@ import 'package:flutter_app_badge/flutter_app_badge.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 
 import '../push/chat_thread_store.dart';
+import '../push/push_renderer.dart';
+import '../push/push_target.dart';
 import '../routing/app_routes.dart';
 import '../session/session_manager.dart';
 import '../state/app/modules/app_modules.dart';
 import '../state/app/modules/chat_list/bloc/chat_list_bloc.dart';
+import '../state/app/modules/parent_letters/bloc/parent_letters_bloc.dart';
 import 'notification_service.dart';
 
 class NotificationTasks {
@@ -72,6 +75,41 @@ class NotificationTasks {
   /// even if the user has already left.
   static void updateProviders(BuildContext context) {
     context.read<ChatListBloc>().refresh();
+    context.read<ParentLettersBloc>().refresh(silent: true);
+  }
+
+  /// [title] is the notification title, when the tap came with one.
+  static void openPushTarget(
+    BuildContext context,
+    PushTarget target, {
+    String? title,
+  }) {
+    switch (target) {
+      case ParentLetterTarget(:final letterId):
+        if (AppModule.isAvailableFor(
+          Modules.parentLetters,
+          SessionManager().current,
+        )) {
+          AppRoutes.openParentLetter(context, id: letterId);
+        }
+      case NewsletterTarget(:final newsletterId):
+        AppRoutes.openNewsletterById(context, id: newsletterId, title: title);
+      case ChatTarget(:final chatToken):
+        navigateToTalk(context, chatToken: chatToken);
+    }
+  }
+
+  /// Removes the letter's tray notification (Android; iOS alerts are posted by
+  /// the system and cannot be addressed by id).
+  static Future<void> clearParentLetterNotification(String letterId) async {
+    try {
+      await NotificationService().flutterLocalNotificationsPlugin.cancel(
+        id: PushRenderer.parentLetterNotificationId(letterId),
+      );
+      await refreshBadge();
+    } on Object catch (e) {
+      log('Parent letter notification cleanup failed: $e');
+    }
   }
 
   /// Switches to the Talk tab. If [chatToken] is provided, also schedules