redesigned payment page + a lot of fixes

frontend/pweb/lib/controllers/signup/confirmation_card.dart

@@ -1,12 +1,11 @@
-import 'dart:async';
-
 import 'package:flutter/foundation.dart';
 
 import 'package:pshared/provider/account.dart';
 
-import 'package:pweb/models/flow_status.dart';
-import 'package:pweb/models/resend/action_result.dart';
-import 'package:pweb/models/resend/avaliability.dart';
+import 'package:pweb/controllers/common/cooldown.dart';
+import 'package:pweb/models/state/flow_status.dart';
+import 'package:pweb/models/auth/resend/action_result.dart';
+import 'package:pweb/models/auth/resend/avaliability.dart';
 
 
 class SignupConfirmationCardController extends ChangeNotifier {
@@ -14,18 +13,17 @@ class SignupConfirmationCardController extends ChangeNotifier {
     required AccountProvider accountProvider,
     Duration defaultCooldown = const Duration(seconds: 60),
   }) : _accountProvider = accountProvider,
-       _defaultCooldown = defaultCooldown;
+       _defaultCooldown = defaultCooldown {
+    _cooldown = CooldownController(onTick: () => notifyListeners());
+  }
 
   final AccountProvider _accountProvider;
   final Duration _defaultCooldown;
-
-  Timer? _cooldownTimer;
-  DateTime? _cooldownUntil;
-  int _cooldownRemainingSeconds = 0;
+  late final CooldownController _cooldown;
   FlowStatus _resendState = FlowStatus.idle;
   String? _email;
 
-  int get cooldownRemainingSeconds => _cooldownRemainingSeconds;
+  int get cooldownRemainingSeconds => _cooldown.remainingSeconds;
   ResendAvailability get resendAvailability {
     final email = _email;
     if (email == null || email.isEmpty) {
@@ -34,7 +32,7 @@ class SignupConfirmationCardController extends ChangeNotifier {
     if (_resendState == FlowStatus.submitting) {
       return ResendAvailability.resending;
     }
-    if (_cooldownRemainingSeconds > 0) {
+    if (_cooldown.isActive) {
       return ResendAvailability.cooldown;
     }
     return ResendAvailability.available;
@@ -85,43 +83,12 @@ class SignupConfirmationCardController extends ChangeNotifier {
 
   @override
   void dispose() {
-    _cooldownTimer?.cancel();
+    _cooldown.dispose();
     super.dispose();
   }
 
   void _startCooldown(Duration duration) {
-    _cooldownTimer?.cancel();
-    _cooldownUntil = DateTime.now().add(duration);
-    _syncRemaining();
-
-    if (_cooldownRemainingSeconds <= 0) {
-      _cooldownUntil = null;
-      notifyListeners();
-      return;
-    }
-
-    _cooldownTimer = Timer.periodic(const Duration(seconds: 1), (timer) {
-      _syncRemaining();
-      if (_cooldownRemainingSeconds <= 0) {
-        timer.cancel();
-        _cooldownUntil = null;
-        notifyListeners();
-      }
-    });
-  }
-
-  void _syncRemaining() {
-    final remaining = _cooldownRemaining();
-    if (remaining == _cooldownRemainingSeconds) return;
-    _cooldownRemainingSeconds = remaining;
-    notifyListeners();
-  }
-
-  int _cooldownRemaining() {
-    final until = _cooldownUntil;
-    if (until == null) return 0;
-    final remaining = until.difference(DateTime.now()).inSeconds;
-    return remaining < 0 ? 0 : remaining;
+    _cooldown.start(duration);
   }
 
   void _setResendState(FlowStatus state) {