show warning if exchanging with slow fee (#579)

* show warning if exchanging with slow fee

* Update setDefaultTransactionPriority for return type void; update for use MoneroTransactionPriority.automatic instead of MoneroTransactionPriority.regular.

Co-authored-by: M <m@cakewallet.com>

lib/di.dart

@@ -494,6 +494,7 @@ Future setup(
       getIt.get<TradesStore>(),
       getIt.get<AppStore>().settingsStore,
       getIt.get<SharedPreferences>(),
+      getIt.get<SettingsViewModel>(),
   ));
 
   getIt.registerFactory(() => ExchangeTradeViewModel(

lib/src/screens/exchange/exchange_page.dart

@@ -111,6 +111,10 @@ class ExchangePage extends BasePage {
     WidgetsBinding.instance
         .addPostFrameCallback((_) => _setReactions(context, exchangeViewModel));
 
+    if (exchangeViewModel.isLowFee) {
+      _showFeeAlert(context);
+    }
+
     return KeyboardActions(
         disableScroll: true,
         config: KeyboardActionsConfig(
@@ -794,5 +798,23 @@ class ExchangePage extends BasePage {
     return address;
   }
 
+  void _showFeeAlert(BuildContext context) async {
+    await Future<void>.delayed(Duration(seconds: 1));
+    final confirmed = await showPopUp<bool>(
+        context: context,
+        builder: (dialogContext) {
+          return AlertWithTwoActions(
+              alertTitle: S.of(context).low_fee,
+              alertContent: S.of(context).low_fee_alert,
+              leftButtonText: S.of(context).ignor,
+              rightButtonText: S.of(context).use_suggested,
+              actionLeftButton: () => Navigator.of(context).pop(false),
+              actionRightButton: () => Navigator.of(context).pop(true));
+        }) ?? false;
+    if (confirmed) {
+      exchangeViewModel.setDefaultTransactionPriority();
+    }
+  }
+
   void disposeBestRateSync() => exchangeViewModel.bestRateSync?.cancel();
 }

lib/view_model/exchange/exchange_view_model.dart

@@ -6,6 +6,10 @@ import 'package:cake_wallet/entities/preferences_key.dart';
 import 'package:cake_wallet/exchange/sideshift/sideshift_exchange_provider.dart';
 import 'package:cake_wallet/exchange/sideshift/sideshift_request.dart';
 import 'package:cake_wallet/exchange/simpleswap/simpleswap_exchange_provider.dart';
+import 'package:cake_wallet/view_model/settings/settings_view_model.dart';
+import 'package:cw_bitcoin/bitcoin_transaction_priority.dart';
+import 'package:cw_core/monero_transaction_priority.dart';
+import 'package:cw_core/transaction_priority.dart';
 import 'package:cake_wallet/exchange/simpleswap/simpleswap_request.dart';
 import 'package:cw_core/wallet_base.dart';
 import 'package:cw_core/crypto_currency.dart';
@@ -40,7 +44,7 @@ class ExchangeViewModel = ExchangeViewModelBase with _$ExchangeViewModel;
 
 abstract class ExchangeViewModelBase with Store {
   ExchangeViewModelBase(this.wallet, this.trades, this._exchangeTemplateStore,
-      this.tradesStore, this._settingsStore, this.sharedPreferences)
+      this.tradesStore, this._settingsStore, this.sharedPreferences, this._settingsViewModel)
     : _cryptoNumberFormat = NumberFormat(),
       isReverse = false,
       isFixedRateMode = false,
@@ -192,6 +196,20 @@ abstract class ExchangeViewModelBase with Store {
 
   bool get isMoneroWallet  => wallet.type == WalletType.monero;
 
+  bool get isLowFee  {
+    switch (wallet.type) {
+      case WalletType.monero:
+      case WalletType.haven:
+        return _settingsViewModel.transactionPriority == MoneroTransactionPriority.slow;
+      case WalletType.bitcoin:
+        return _settingsViewModel.transactionPriority == BitcoinTransactionPriority.slow;
+      case WalletType.litecoin:
+        return _settingsViewModel.transactionPriority == LitecoinTransactionPriority.slow;
+      default:
+        return false;
+    }
+  }
+
   List<CryptoCurrency> receiveCurrencies;
 
   List<CryptoCurrency> depositCurrencies;
@@ -204,6 +222,8 @@ abstract class ExchangeViewModelBase with Store {
 
   final SettingsStore _settingsStore;
 
+  final SettingsViewModel _settingsViewModel;
+
   double _bestRate = 0.0;
 
   late Timer bestRateSync;
@@ -611,4 +631,22 @@ abstract class ExchangeViewModelBase with Store {
         selectedProviders
             .where((provider) => providersForCurrentPair().contains(provider)));
   }
+
+  @action
+  void setDefaultTransactionPriority() {
+    switch (wallet.type) {
+      case WalletType.monero:
+      case WalletType.haven:
+        _settingsStore.priority[wallet.type] = MoneroTransactionPriority.automatic;
+        break;
+      case WalletType.bitcoin:
+        _settingsStore.priority[wallet.type] = BitcoinTransactionPriority.medium;
+        break;
+      case WalletType.litecoin:
+        _settingsStore.priority[wallet.type] = LitecoinTransactionPriority.medium;
+        break;
+      default:
+        break;
+    }
+  }
 }