redesigned payment page + a lot of fixes

frontend/pweb/lib/pages/loaders/account.dart

@@ -6,7 +6,9 @@ import 'package:pshared/models/auth/state.dart';
 import 'package:pshared/provider/account.dart';
 
 import 'package:pweb/app/router/pages.dart';
+import 'package:pweb/controllers/auth/account_loader.dart';
 import 'package:pweb/utils/error/snackbar.dart';
+import 'package:pweb/models/account/account_loader.dart';
 
 import 'package:pweb/generated/i18n/app_localizations.dart';
 
@@ -20,29 +22,29 @@ class AccountLoader extends StatefulWidget {
 }
 
 class _AccountLoaderState extends State<AccountLoader> {
-  AuthState? _handledState;
+  late final AccountLoaderController _controller;
 
   @override
   void initState() {
     super.initState();
+    _controller = AccountLoaderController()..addListener(_handleControllerAction);
     WidgetsBinding.instance.addPostFrameCallback((_) {
       if (!mounted) return;
       Provider.of<AccountProvider>(context, listen: false).restoreIfPossible();
     });
   }
 
-  void _handleSideEffects(AccountProvider provider) {
-    if (_handledState == provider.authState) return;
-    _handledState = provider.authState;
-
+  void _handleControllerAction() {
+    final action = _controller.consumeAction();
+    if (action == null) return;
     void goToLogin() {
       if (!mounted) return;
       navigateAndReplace(context, Pages.login);
     }
 
-    switch (provider.authState) {
-      case AuthState.error:
-        final error = provider.error ?? Exception('Authorization failed');
+    switch (action) {
+      case AccountLoaderAction.showErrorAndGoToLogin:
+        final error = _controller.error ?? Exception('Authorization failed');
         WidgetsBinding.instance.addPostFrameCallback((_) {
           if (!mounted) return;
           postNotifyUserOfErrorX(
@@ -53,18 +55,23 @@ class _AccountLoaderState extends State<AccountLoader> {
           goToLogin();
         });
         break;
-      case AuthState.empty:
+      case AccountLoaderAction.goToLogin:
         WidgetsBinding.instance.addPostFrameCallback((_) => goToLogin());
         break;
-      default:
-        break;
     }
   }
 
+  @override
+  void dispose() {
+    _controller.removeListener(_handleControllerAction);
+    _controller.dispose();
+    super.dispose();
+  }
+
   @override
   Widget build(BuildContext context) {
     return Consumer<AccountProvider>(builder: (context, provider, _) {
-      _handleSideEffects(provider);
+      _controller.update(provider);
       if (provider.authState == AuthState.ready && provider.account != null) {
         return widget.child;
       }