added support for multiple accounts with an account switcher in settings

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),
         ),
       ),
     );