Fix

app/lib/main/sharezone_bloc_providers.dart

@@ -92,6 +92,7 @@ import 'package:sharezone/settings/src/subpages/imprint/bloc/imprint_bloc_factor
 import 'package:sharezone/settings/src/subpages/imprint/gateway/imprint_gateway.dart';
 import 'package:sharezone/settings/src/subpages/my_profile/change_type_of_user/change_type_of_user_analytics.dart';
 import 'package:sharezone/settings/src/subpages/my_profile/change_type_of_user/change_type_of_user_controller.dart';
+import 'package:sharezone/settings/src/subpages/my_profile/change_type_of_user/change_type_of_user_repository.dart';
 import 'package:sharezone/settings/src/subpages/timetable/bloc/timetable_settings_bloc_factory.dart';
 import 'package:sharezone/settings/src/subpages/timetable/time_picker_settings_cache.dart';
 import 'package:sharezone/sharezone_plus/page/sharezone_plus_page_controller.dart';
@@ -365,6 +366,9 @@ class _SharezoneBlocProvidersState extends State<SharezoneBlocProviders> {
       ),
       ChangeNotifierProvider(
         create: (context) => ChangeTypeOfUserController(
+          repository: ChangeTypeOfUserRepository(
+            functions: widget.blocDependencies.functions,
+          ),
           typeOfUserStream: typeOfUserStream,
           analytics: ChangeTypeOfUserAnalytics(analytics),
           userId: UserId(api.uID),

app/lib/settings/src/subpages/my_profile/change_type_of_user/change_type_of_user_controller.dart

@@ -1,14 +1,16 @@
 import 'dart:async';
 
+import 'package:cloud_functions/cloud_functions.dart';
 import 'package:common_domain_models/common_domain_models.dart';
 import 'package:flutter/material.dart';
 import 'package:sharezone/settings/src/subpages/my_profile/change_type_of_user/change_type_of_user_analytics.dart';
+import 'package:sharezone/settings/src/subpages/my_profile/change_type_of_user/change_type_of_user_repository.dart';
 import 'package:user/user.dart';
 
 class ChangeTypeOfUserController extends ChangeNotifier {
-  /// The user ID of the user whose type of user should be changed.
   final UserId userId;
   final ChangeTypeOfUserAnalytics analytics;
+  final ChangeTypeOfUserRepository repository;
   StreamSubscription<TypeOfUser?>? _typeOfUserSubscription;
 
   late ChangeTypeOfUserState state;
@@ -22,6 +24,7 @@ class ChangeTypeOfUserController extends ChangeNotifier {
   ChangeTypeOfUserController({
     required this.userId,
     required this.analytics,
+    required this.repository,
     required Stream<TypeOfUser?> typeOfUserStream,
   }) {
     state = const ChangeTypeOfUserInitial();
@@ -38,29 +41,27 @@ class ChangeTypeOfUserController extends ChangeNotifier {
   Future<void> changeTypeOfUser() async {
     final typeOfUser = selectedTypeOfUser;
     if (typeOfUser == null) {
-      state = const NoTypeOfUserSelectedException();
-      notifyListeners();
-      return;
+      throw const NoTypeOfUserSelectedException();
     }
 
     if (typeOfUser == initialTypeOfUser) {
-      state = const TypeUserOfUserHasNotChangedException();
-      notifyListeners();
-      return;
+      throw const TypeUserOfUserHasNotChangedException();
     }
 
     try {
-      // Call backend...
-      await Future.delayed(const Duration(seconds: 1));
+      await repository.changeTypeOfUser(typeOfUser);
 
       analytics.logChangedOrder(
         from: initialTypeOfUser,
         to: typeOfUser,
       );
       initialTypeOfUser = typeOfUser;
       state = const ChangedTypeOfUserSuccessfully();
+    } on FirebaseFunctionsException catch (e) {
+      throw ChangeTypeOfUserUnknownException(
+          '[${e.plugin}/${e.code}] ${e.message}');
     } catch (e) {
-      state = ChangeTypeOfUserUnknownException(e);
+      throw ChangeTypeOfUserUnknownException(e);
     } finally {
       notifyListeners();
     }
@@ -90,7 +91,7 @@ class ChangedTypeOfUserSuccessfully extends ChangeTypeOfUserState {
   const ChangedTypeOfUserSuccessfully();
 }
 
-sealed class ChangeTypeOfUserFailed extends ChangeTypeOfUserState {
+sealed class ChangeTypeOfUserFailed {
   const ChangeTypeOfUserFailed();
 }
 

app/lib/settings/src/subpages/my_profile/change_type_of_user/change_type_of_user_page.dart

@@ -45,6 +45,7 @@ class _SaveFab extends StatelessWidget {
         TypeUserOfUserHasNotChangedException() =>
           'Der Account-Typ hat sich nicht geändert.',
       },
+      context: context,
     );
   }
 
@@ -60,6 +61,7 @@ class _SaveFab extends StatelessWidget {
           await controller.changeTypeOfUser();
 
           if (context.mounted) {
+            ScaffoldMessenger.of(context).hideCurrentSnackBar();
             _showRestartDialog(context);
           }
         } on ChangeTypeOfUserFailed catch (e) {
@@ -112,7 +114,8 @@ class _ChangeTypeOfUser extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final controller = context.watch<ChangeTypeOfUserController>();
-    final selectedTypeOfUser = controller.selectedTypeOfUser;
+    final selectedTypeOfUser =
+        controller.selectedTypeOfUser ?? controller.initialTypeOfUser;
     return Column(
       children: [
         for (final typeOfUser in [

app/lib/settings/src/subpages/my_profile/change_type_of_user/change_type_of_user_repository.dart

@@ -0,0 +1,17 @@
+import 'package:cloud_functions/cloud_functions.dart';
+import 'package:user/user.dart';
+
+class ChangeTypeOfUserRepository {
+  final FirebaseFunctions _functions;
+
+  const ChangeTypeOfUserRepository({
+    required FirebaseFunctions functions,
+  }) : _functions = functions;
+
+  Future<void> changeTypeOfUser(TypeOfUser typeOfUser) async {
+    final callable = _functions.httpsCallable('changeTypeOfUser');
+    await callable.call({
+      'type': typeOfUser.name,
+    });
+  }
+}