changed color theme to be black and added the ability to enter the amount in the recipient’s currency

frontend/pweb/lib/controllers/payments/amount_field.dart

@@ -1,25 +1,56 @@
 import 'package:flutter/material.dart';
 
+import 'package:pshared/controllers/balance_mask/wallets.dart';
+import 'package:pshared/models/payment/settlement_mode.dart';
 import 'package:pshared/provider/payment/amount.dart';
 import 'package:pshared/utils/currency.dart';
 import 'package:pshared/utils/money.dart';
 
+import 'package:pweb/models/payment/amount/mode.dart';
 
 class PaymentAmountFieldController extends ChangeNotifier {
+  static const String _settlementCurrencyCode = 'RUB';
+
   final TextEditingController textController;
+  final FocusNode focusNode = FocusNode();
+
   PaymentAmountProvider? _provider;
+  WalletsController? _wallets;
   bool _isSyncingText = false;
+  PaymentAmountMode _mode = PaymentAmountMode.debit;
 
   PaymentAmountFieldController({required double initialAmount})
-      : textController = TextEditingController(
-          text: amountToString(initialAmount),
-        );
+    : textController = TextEditingController(
+        text: amountToString(initialAmount),
+      );
+
+  PaymentAmountMode get mode => _mode;
+  bool get isReverseModeAvailable {
+    final sourceCurrencyCode = _sourceCurrencyCode;
+    return sourceCurrencyCode != null &&
+        sourceCurrencyCode != _settlementCurrencyCode;
+  }
+
+  String? get activeCurrencyCode => switch (_mode) {
+    PaymentAmountMode.debit => _sourceCurrencyCode,
+    PaymentAmountMode.settlement => _settlementCurrencyCode,
+  };
+
+  void update(PaymentAmountProvider provider, WalletsController wallets) {
+    if (!identical(_provider, provider)) {
+      _provider?.removeListener(_handleProviderChanged);
+      _provider = provider;
+      _provider?.addListener(_handleProviderChanged);
+      _syncModeWithProvider(provider);
+    }
+
+    if (!identical(_wallets, wallets)) {
+      _wallets?.removeListener(_handleWalletsChanged);
+      _wallets = wallets;
+      _wallets?.addListener(_handleWalletsChanged);
+      _normalizeModeForWallet();
+    }
 
-  void update(PaymentAmountProvider provider) {
-    if (identical(_provider, provider)) return;
-    _provider?.removeListener(_handleProviderChanged);
-    _provider = provider;
-    _provider?.addListener(_handleProviderChanged);
     _syncTextWithAmount(provider.amount);
   }
 
@@ -31,12 +62,70 @@ class PaymentAmountFieldController extends ChangeNotifier {
     }
   }
 
+  void handleModeChanged(PaymentAmountMode value) {
+    if (value == _mode) return;
+    if (!isReverseModeAvailable && value == PaymentAmountMode.settlement) {
+      return;
+    }
+
+    _mode = value;
+    _provider?.setSettlementMode(_settlementModeFromMode(value));
+    notifyListeners();
+  }
+
   void _handleProviderChanged() {
     final provider = _provider;
     if (provider == null) return;
     _syncTextWithAmount(provider.amount);
+    final changed = _syncModeWithProvider(provider);
+    if (changed) {
+      _normalizeModeForWallet();
+      notifyListeners();
+    }
   }
 
+  void _handleWalletsChanged() {
+    final changed = _normalizeModeForWallet();
+    if (changed) {
+      notifyListeners();
+    }
+  }
+
+  bool _syncModeWithProvider(PaymentAmountProvider provider) {
+    final nextMode = _modeFromSettlementMode(provider.settlementMode);
+    if (nextMode == _mode) return false;
+    _mode = nextMode;
+    return true;
+  }
+
+  bool _normalizeModeForWallet() {
+    if (isReverseModeAvailable || _mode != PaymentAmountMode.settlement) {
+      return false;
+    }
+    _mode = PaymentAmountMode.debit;
+    _provider?.setSettlementMode(SettlementMode.fixSource);
+    return true;
+  }
+
+  String? get _sourceCurrencyCode {
+    final selectedWallet = _wallets?.selectedWallet;
+    if (selectedWallet == null) return null;
+    return currencyCodeToString(selectedWallet.currency);
+  }
+
+  PaymentAmountMode _modeFromSettlementMode(SettlementMode mode) =>
+      switch (mode) {
+        SettlementMode.fixReceived => PaymentAmountMode.settlement,
+        SettlementMode.fixSource ||
+        SettlementMode.unspecified => PaymentAmountMode.debit,
+      };
+
+  SettlementMode _settlementModeFromMode(PaymentAmountMode mode) =>
+      switch (mode) {
+        PaymentAmountMode.debit => SettlementMode.fixSource,
+        PaymentAmountMode.settlement => SettlementMode.fixReceived,
+      };
+
   double? _parseAmount(String value) {
     final parsed = parseMoneyAmount(
       value.replaceAll(',', '.'),
@@ -61,6 +150,8 @@ class PaymentAmountFieldController extends ChangeNotifier {
   @override
   void dispose() {
     _provider?.removeListener(_handleProviderChanged);
+    _wallets?.removeListener(_handleWalletsChanged);
+    focusNode.dispose();
     textController.dispose();
     super.dispose();
   }