added support for multiple accounts with an account switcher in settings

lib/view/login/login.dart

@@ -1,12 +1,13 @@
 import 'dart:async';
+import 'dart:developer';
 
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 
 import '../../background/widget_background_task.dart';
 import '../../session/session_lifecycle.dart';
+import '../../session/session_manager.dart';
 import '../../state/app/modules/account/bloc/account_bloc.dart';
-import '../../state/app/modules/account/bloc/account_state.dart';
 import '../../state/app/modules/settings/bloc/settings_cubit.dart';
 import '../../storage/dev_tools_settings.dart';
 import '../../storage/settings.dart' as model;
@@ -20,7 +21,10 @@ import 'widgets/login_branding.dart';
 import 'widgets/login_card.dart';
 
 class Login extends StatefulWidget {
-  const Login({super.key});
+  /// Signs in another account while one is active; offers to go back.
+  final bool addingAccount;
+
+  const Login({super.key, this.addingAccount = false});
 
   @override
   State<Login> createState() => _LoginState();
@@ -65,59 +69,100 @@ class _LoginState extends State<Login> with SingleTickerProviderStateMixin {
     super.dispose();
   }
 
-  void _onLoginSuccess() {
+  Future<void> _onLoginSuccess() async {
     Haptics.heavyAccent();
+    final accountBloc = context.read<AccountBloc>();
+    // Fade the login content out before handing over to the post-login splash.
+    // Both share the red backdrop, so this reads as one continuous transition
+    // instead of an abrupt swap.
+    final finished = SessionLifecycle.finishLogin();
+    await _fade.reverse().orCancel.onError<TickerCanceled>((_, _) {});
+    String? accountId;
+    try {
+      accountId = await finished;
+    } on Object catch (e) {
+      log('Login: finishing failed: $e');
+      accountId = SessionManager().activeAccount?.id;
+    }
     // Re-register the periodic refresh (cancelAll runs on logout) and kick
     // off an immediate one-off so the widget populates within seconds
     // instead of waiting up to 30 minutes for the next periodic slot.
     unawaited(WidgetBackgroundTask.initialize());
     unawaited(WidgetBackgroundTask.requestImmediateRefresh());
-    // Fade the login content out before handing over to the post-login splash.
-    // Both share the red backdrop, so this reads as one continuous transition
-    // instead of an abrupt swap.
-    _fade.reverse().whenComplete(() {
-      if (!mounted) return;
-      context.read<AccountBloc>().setStatus(AccountStatus.loggedIn);
-    });
+    accountBloc.activated(accountId, freshLogin: true);
+  }
+
+  Future<void> _cancelAddAccount() async {
+    final accountBloc = context.read<AccountBloc>();
+    await SessionLifecycle.cancelAddAccount();
+    accountBloc.activated(SessionManager().activeAccount?.id);
   }
 
   @override
-  Widget build(BuildContext context) => Scaffold(
-    backgroundColor: _marianumRed,
-    body: FadeTransition(
-      opacity: _fade,
-      child: SafeArea(
-        child: LayoutBuilder(
-          builder: (context, constraints) => SingleChildScrollView(
-            padding: const EdgeInsets.symmetric(horizontal: 24),
-            child: Center(
-              child: ConstrainedBox(
-                constraints: BoxConstraints(
-                  minHeight: constraints.maxHeight,
-                  maxWidth: 420,
+  Widget build(BuildContext context) => PopScope(
+    canPop: !widget.addingAccount,
+    onPopInvokedWithResult: (didPop, _) {
+      if (!didPop && !_busy) unawaited(_cancelAddAccount());
+    },
+    child: Scaffold(
+      backgroundColor: _marianumRed,
+      appBar: widget.addingAccount
+          ? AppBar(
+              backgroundColor: Colors.transparent,
+              foregroundColor: Colors.white,
+              elevation: 0,
+              leading: ListenableBuilder(
+                listenable: _controller,
+                builder: (context, _) => IconButton(
+                  icon: const Icon(Icons.close),
+                  tooltip: 'Abbrechen',
+                  onPressed: _busy ? null : _cancelAddAccount,
                 ),
-                // spaceBetween statt Spacer-in-IntrinsicHeight: Letzteres würde
-                // die Column bei Inhaltsänderungen im unteren Block auf die
-                // intrinsic-Höhe pinnen und ein paar Pixel Overflow erzeugen.
-                child: Column(
-                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
-                  children: [
-                    Column(
-                      children: [
-                        const LoginHeader(),
-                        const SizedBox(height: 28),
-                        LoginCard(
-                          controller: _controller,
-                          onSuccess: _onLoginSuccess,
-                        ),
-                        const SizedBox(height: 12),
-                      ],
-                    ),
-                    const Column(
-                      mainAxisSize: MainAxisSize.min,
-                      children: [_EndpointLink(), LoginFooter()],
-                    ),
-                  ],
+              ),
+              title: const Text('Konto hinzufügen'),
+            )
+          : null,
+      body: FadeTransition(
+        opacity: _fade,
+        child: SafeArea(
+          child: LayoutBuilder(
+            builder: (context, constraints) => SingleChildScrollView(
+              padding: const EdgeInsets.symmetric(horizontal: 24),
+              child: Center(
+                child: ConstrainedBox(
+                  constraints: BoxConstraints(
+                    minHeight: constraints.maxHeight,
+                    maxWidth: 420,
+                  ),
+                  // spaceBetween statt Spacer-in-IntrinsicHeight: Letzteres würde
+                  // die Column bei Inhaltsänderungen im unteren Block auf die
+                  // intrinsic-Höhe pinnen und ein paar Pixel Overflow erzeugen.
+                  child: Column(
+                    mainAxisAlignment: MainAxisAlignment.spaceBetween,
+                    children: [
+                      Column(
+                        children: [
+                          LoginHeader(addingAccount: widget.addingAccount),
+                          const SizedBox(height: 28),
+                          LoginCard(
+                            controller: _controller,
+                            onSuccess: _onLoginSuccess,
+                            addingAccount: widget.addingAccount,
+                          ),
+                          const SizedBox(height: 12),
+                        ],
+                      ),
+                      Column(
+                        mainAxisSize: MainAxisSize.min,
+                        children: [
+                          // The new account must live on the server the app
+                          // already talks to.
+                          if (!widget.addingAccount) const _EndpointLink(),
+                          const LoginFooter(),
+                        ],
+                      ),
+                    ],
+                  ),
                 ),
               ),
             ),
@@ -126,6 +171,8 @@ class _LoginState extends State<Login> with SingleTickerProviderStateMixin {
       ),
     ),
   );
+
+  bool get _busy => _controller.loading;
 }
 
 /// Subtle text link above the footer that surfaces the currently selected

lib/view/login/widgets/login_branding.dart

@@ -1,7 +1,10 @@
 import 'package:flutter/material.dart';
 
 class LoginHeader extends StatelessWidget {
-  const LoginHeader({super.key});
+  /// Signs in an additional account instead of the first one.
+  final bool addingAccount;
+
+  const LoginHeader({this.addingAccount = false, super.key});
 
   @override
   Widget build(BuildContext context) => Column(
@@ -29,7 +32,10 @@ class LoginHeader extends StatelessWidget {
       ),
       const SizedBox(height: 6),
       Text(
-        'Stundenplan, Talk, Dateien und mehr - alles an einem Ort für deinen Schulalltag am Marianum Fulda.',
+        addingAccount
+            ? 'Melde ein weiteres Konto an. In den Einstellungen kannst du '
+                  'danach jederzeit zwischen deinen Konten wechseln.'
+            : 'Stundenplan, Talk, Dateien und mehr - alles an einem Ort für deinen Schulalltag am Marianum Fulda.',
         textAlign: TextAlign.center,
         style: TextStyle(
           color: Colors.white.withValues(alpha: 0.85),

lib/view/login/widgets/login_card.dart

@@ -12,9 +12,13 @@ class LoginCard extends StatefulWidget {
   final LoginController controller;
   final VoidCallback onSuccess;
 
+  /// Signs in an additional account instead of the first one.
+  final bool addingAccount;
+
   const LoginCard({
     required this.controller,
     required this.onSuccess,
+    this.addingAccount = false,
     super.key,
   });
 
@@ -83,8 +87,11 @@ class _LoginCardState extends State<LoginCard> {
     return Form(
       key: _formKey,
       child: LoginCardFrame(
-        title: 'Anmelden',
-        hint: 'Melde dich mit deinen Marianum-Zugangsdaten an.',
+        title: widget.addingAccount ? 'Konto hinzufügen' : 'Anmelden',
+        hint: widget.addingAccount
+            ? 'Melde dich mit den Marianum-Zugangsdaten des Kontos an, das '
+                  'du hinzufügen möchtest.'
+            : 'Melde dich mit deinen Marianum-Zugangsdaten an.',
         children: [
           TextFormField(
             key: const Key('login-username-field'),
@@ -127,7 +134,7 @@ class _LoginCardState extends State<LoginCard> {
           const SizedBox(height: 20),
           LoginSubmitButton(
             key: const Key('login-submit-button'),
-            label: 'Anmelden',
+            label: widget.addingAccount ? 'Hinzufügen' : 'Anmelden',
             loading: loading,
             onPressed: _submit,
           ),

lib/view/pages/settings/diagnostics_page.dart

@@ -16,7 +16,7 @@ import '../../../extensions/date_time.dart';
 import '../../../model/endpoint_data.dart';
 import '../../../push/push_registration_store.dart';
 import '../../../push/push_registration_type.dart';
-import '../../../session/session.dart';
+import '../../../session/account_codec.dart';
 import '../../../session/session_manager.dart';
 import '../../../state/app/modules/account/bloc/account_bloc.dart';
 import '../../../state/app/modules/settings/bloc/settings_cubit.dart';
@@ -103,10 +103,9 @@ class _DiagnosticsPageState extends State<DiagnosticsPage> {
         title: 'Sitzung',
         rows: await rows({
           'Status': () async => accountStatus.name,
-          'Benutzer': () async => switch (session) {
-            CredentialSession(:final username) => username,
-            null => null,
-          },
+          'Benutzer': () async =>
+              session == null ? null : identityOf(session).$2,
+          'Konten': () async => SessionManager().accounts.value.accounts.length,
           'Demo-Modus': () async => session?.isDemo ?? false,
           'Login Flow v2': () async => nextcloud?.usesLoginFlow ?? false,
           'App-Passwort (Dateien)': () async =>

lib/view/pages/settings/sections/account_section.dart

@@ -9,7 +9,7 @@ import '../../../../routing/app_routes.dart';
 import '../../../../session/session_lifecycle.dart';
 import '../../../../session/session_manager.dart';
 import '../../../../state/app/modules/account/bloc/account_bloc.dart';
-import '../../../../state/app/modules/account/bloc/account_state.dart';
+import '../../../../widget/account_switcher_sheet.dart';
 import '../../../../widget/app_progress_indicator.dart';
 import '../../../../widget/async_action_button.dart';
 import '../../../../widget/avatar_actions_sheet.dart';
@@ -17,34 +17,43 @@ import '../../../../widget/confirm_dialog.dart';
 import '../../../../widget/demo_restricted.dart';
 import '../../../../widget/user_avatar.dart';
 
-// Display-name is process-wide stable until the user logs out; cache it so
-// every Settings rebuild doesn't re-issue the OCS request.
+// Display-name is stable per account; cache it so every Settings rebuild
+// doesn't re-issue the OCS request.
 String? _cachedDisplayName;
+String? _cachedDisplayNameFor;
 
-class AccountSection extends StatefulWidget {
+class AccountSection extends StatelessWidget {
   const AccountSection({super.key});
 
   @override
-  State<AccountSection> createState() => _AccountSectionState();
+  Widget build(BuildContext context) => const _SchoolAccount();
 }
 
-class _AccountSectionState extends State<AccountSection> {
+class _SchoolAccount extends StatefulWidget {
+  const _SchoolAccount();
+
+  @override
+  State<_SchoolAccount> createState() => _SchoolAccountState();
+}
+
+class _SchoolAccountState extends State<_SchoolAccount> {
   int _avatarVersion = 0;
   bool _avatarBusy = false;
-  String? _displayName = _cachedDisplayName;
+  String? _displayName;
 
   @override
   void initState() {
     super.initState();
-    if (_displayName == null) _loadDisplayName();
+    final username = SessionManager().requireNextcloud().username;
+    if (_cachedDisplayNameFor == username) _displayName = _cachedDisplayName;
+    if (_displayName == null) _loadDisplayName(username);
   }
 
-  Future<void> _loadDisplayName() async {
+  Future<void> _loadDisplayName(String username) async {
     try {
       final info = await GetUserInfo().run();
-      _cachedDisplayName = info.displayName.isEmpty
-          ? null
-          : info.displayName;
+      _cachedDisplayNameFor = username;
+      _cachedDisplayName = info.displayName.isEmpty ? null : info.displayName;
       if (!mounted) return;
       setState(() => _displayName = _cachedDisplayName);
     } catch (_) {
@@ -102,7 +111,7 @@ class _AccountSectionState extends State<AccountSection> {
       crossAxisAlignment: CrossAxisAlignment.stretch,
       children: [
         Padding(
-          padding: const EdgeInsets.fromLTRB(16, 20, 16, 16),
+          padding: const EdgeInsets.fromLTRB(16, 20, 8, 16),
           child: Row(
             children: [
               SizedBox(
@@ -113,8 +122,10 @@ class _AccountSectionState extends State<AccountSection> {
                   children: [
                     Center(
                       child: GestureDetector(
-                        onTap: () =>
-                            AppRoutes.openLargeProfilePicture(context, username),
+                        onTap: () => AppRoutes.openLargeProfilePicture(
+                          context,
+                          username,
+                        ),
                         child: UserAvatar(
                           key: ValueKey(_avatarVersion),
                           id: username,
@@ -134,7 +145,7 @@ class _AccountSectionState extends State<AccountSection> {
                   ],
                 ),
               ),
-              const SizedBox(width: 16),
+              const SizedBox(width: 12),
               Expanded(
                 child: Column(
                   crossAxisAlignment: CrossAxisAlignment.start,
@@ -167,12 +178,8 @@ class _AccountSectionState extends State<AccountSection> {
                   ],
                 ),
               ),
-              const SizedBox(width: 8),
-              TextButton.icon(
-                icon: const Icon(Icons.logout_outlined, size: 18),
-                label: const Text('Abmelden'),
-                onPressed: () => _showLogoutDialog(context),
-              ),
+              const SizedBox(width: 4),
+              const _AccountActions(),
             ],
           ),
         ),
@@ -183,9 +190,7 @@ class _AccountSectionState extends State<AccountSection> {
           AsyncListTile(
             leading: const Icon(Icons.cloud_sync_outlined),
             title: const Text('Nextcloud neu verbinden'),
-            subtitle: const Text(
-              'Bei Anmeldeproblemen in Talk oder Dateien',
-            ),
+            subtitle: const Text('Bei Anmeldeproblemen in Talk oder Dateien'),
             closeOnSuccess: false,
             onPressed: _reconnectNextcloud,
           ),
@@ -204,29 +209,49 @@ class _AccountSectionState extends State<AccountSection> {
       const SnackBar(content: Text('Nextcloud-Verbindung erneuert.')),
     );
   }
+}
 
-  Future<void> _showLogoutDialog(BuildContext context) async {
-    // Flip AccountBloc state only after the dialog fully closes: doing it from
-    // inside the sign-out (the previous approach) raced AsyncDialogAction's
-    // pop(true) against the listener's popUntil(isFirst) and could leave the
-    // navigator in an inconsistent state.
-    final confirmed = await showDialog<bool>(
-      context: context,
-      builder: (dialogContext) => ConfirmDialog(
-        title: 'Abmelden?',
-        content: 'Möchtest du dich wirklich abmelden?',
-        confirmButton: 'Abmelden',
-        onConfirmAsync: _performLogout,
+Future<void> _confirmLogout(BuildContext context) async {
+  final accountBloc = context.read<AccountBloc>();
+  final others = SessionManager().accounts.value.accounts.length - 1;
+  String? nextAccountId;
+  // Flip AccountBloc state only after the dialog fully closes: doing it from
+  // inside the sign-out (the previous approach) raced AsyncDialogAction's
+  // pop(true) against the navigator teardown of the account switch.
+  final confirmed = await showDialog<bool>(
+    context: context,
+    builder: (dialogContext) => ConfirmDialog(
+      title: 'Abmelden?',
+      content: others > 0
+          ? 'Möchtest du dich wirklich abmelden? Die App wechselt danach zu '
+                'einem deiner anderen Konten.'
+          : 'Möchtest du dich wirklich abmelden?',
+      confirmButton: 'Abmelden',
+      onConfirmAsync: () async =>
+          nextAccountId = await SessionLifecycle.signOut(),
+    ),
+  );
+  if (confirmed != true) return;
+  accountBloc.activated(nextAccountId);
+}
+
+class _AccountActions extends StatelessWidget {
+  const _AccountActions();
+
+  @override
+  Widget build(BuildContext context) => Column(
+    mainAxisSize: MainAxisSize.min,
+    crossAxisAlignment: CrossAxisAlignment.start,
+    children: [
+      TextButton.icon(
+        style: compactAccountButtonStyle,
+        icon: const Icon(Icons.logout_outlined, size: 18),
+        label: const Text('Abmelden'),
+        onPressed: () => _confirmLogout(context),
       ),
-    );
-    if (confirmed != true || !context.mounted) return;
-    context.read<AccountBloc>().setStatus(AccountStatus.loggedOut);
-  }
-
-  Future<void> _performLogout() async {
-    await SessionLifecycle.signOut();
-    _cachedDisplayName = null;
-  }
+      const AccountSwitchButton(),
+    ],
+  );
 }
 
 class _AvatarEditBadge extends StatelessWidget {
@@ -254,11 +279,7 @@ class _AvatarEditBadge extends StatelessWidget {
                     color: theme.colorScheme.onPrimary,
                   ),
                 )
-              : Icon(
-                  Icons.edit,
-                  size: 14,
-                  color: theme.colorScheme.onPrimary,
-                ),
+              : Icon(Icons.edit, size: 14, color: theme.colorScheme.onPrimary),
         ),
       ),
     );