Merge pull request #667 from cake-tech/CW-271-fixed-rate-incorrect-amount

[Cw 271] fixed-rate incorrect amount

lib/exchange/changenow/changenow_exchange_provider.dart

@@ -11,7 +11,6 @@ import 'package:cake_wallet/exchange/trade_request.dart';
 import 'package:cake_wallet/exchange/trade_state.dart';
 import 'package:cake_wallet/exchange/changenow/changenow_request.dart';
 import 'package:cake_wallet/exchange/exchange_provider_description.dart';
-import 'package:cake_wallet/exchange/trade_not_created_exeption.dart';
 
 class ChangeNowExchangeProvider extends ExchangeProvider {
   ChangeNowExchangeProvider()
@@ -21,8 +20,7 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
                 .where((i) => i != CryptoCurrency.xhv)
                 .map((i) => CryptoCurrency.all
                     .where((i) => i != CryptoCurrency.xhv)
-                    .map((k) => ExchangePair(from: i, to: k, reverse: true))
+                    .map((k) => ExchangePair(from: i, to: k, reverse: true)))
-                    .where((c) => c != null))
                 .expand((i) => i)
                 .toList());
 
@@ -43,6 +41,9 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
   @override
   bool get isEnabled => true;
 
+  @override
+  bool get supportsFixedRate => true;
+
   @override
   ExchangeProviderDescription get description =>
       ExchangeProviderDescription.changeNow;
@@ -96,19 +97,30 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
       apiHeaderKey: apiKey,
       'Content-Type': 'application/json'};
     final flow = getFlow(isFixedRateMode);
+    final type = isFixedRateMode ? 'reverse' : 'direct';
     final body = <String, String>{
       'fromCurrency': normalizeCryptoCurrency(_request.from),
       'toCurrency': normalizeCryptoCurrency(_request.to),
       'fromNetwork': networkFor(_request.from),
       'toNetwork': networkFor(_request.to),
-      'fromAmount': _request.fromAmount,
+      if (!isFixedRateMode) 'fromAmount': _request.fromAmount,
-      'toAmount': _request.toAmount,
+      if (isFixedRateMode) 'toAmount': _request.toAmount,
       'address': _request.address,
       'flow': flow,
+      'type': type,
       'refundAddress': _request.refundAddress
     };
 
     if (isFixedRateMode) {
+      // since we schedule to calculate the rate every 5 seconds we need to ensure that
+      // we have the latest rate id with the given inputs before creating the trade
+      await fetchRate(
+        from: _request.from,
+        to: _request.to,
+        amount: double.tryParse(_request.toAmount) ?? 0,
+        isFixedRateMode: true,
+        isReceiveAmount: true,
+      );
       body['rateId'] = _lastUsedRateId;
     }
 
@@ -141,7 +153,7 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
         refundAddress: refundAddress,
         extraId: extraId,
         createdAt: DateTime.now(),
-        amount: _request.fromAmount,
+        amount: responseJSON['fromAmount']?.toString() ?? _request.fromAmount,
         state: TradeState.created);
   }
 
@@ -180,9 +192,7 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
     final extraId = responseJSON['payinExtraId'] as String;
     final outputTransaction = responseJSON['payoutHash'] as String;
     final expiredAtRaw = responseJSON['validUntil'] as String;
-    final expiredAt = expiredAtRaw != null
+    final expiredAt = DateTime.tryParse(expiredAtRaw)?.toLocal();
-        ? DateTime.parse(expiredAtRaw).toLocal()
-        : null;
 
     return Trade(
         id: id,
@@ -198,7 +208,7 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
   }
 
   @override
-  Future<double> calculateAmount(
+  Future<double> fetchRate(
       {required CryptoCurrency from,
       required CryptoCurrency to,
       required double amount,
@@ -214,10 +224,10 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
       final type = isReverse ? 'reverse' : 'direct';
       final flow = getFlow(isFixedRateMode);
       final params = <String, String>{
-        'fromCurrency': isReverse ? normalizeCryptoCurrency(to) : normalizeCryptoCurrency(from),
+        'fromCurrency': normalizeCryptoCurrency(from),
-        'toCurrency': isReverse ? normalizeCryptoCurrency(from) : normalizeCryptoCurrency(to),
+        'toCurrency': normalizeCryptoCurrency(to),
-        'fromNetwork': isReverse ? networkFor(to) : networkFor(from),
+        'fromNetwork': networkFor(from),
-        'toNetwork': isReverse ? networkFor(from) : networkFor(to),
+        'toNetwork': networkFor(to),
         'type': type,
         'flow': flow};
 
@@ -238,7 +248,7 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
         _lastUsedRateId = rateId;
       }
 
-      return isReverse ? fromAmount : toAmount;
+      return isReverse ? (amount / fromAmount) : (toAmount / amount);
     } catch(e) {
       print(e.toString());
       return 0.0;

lib/exchange/exchange_provider.dart

@@ -1,4 +1,3 @@
-import 'package:flutter/foundation.dart';
 import 'package:cw_core/crypto_currency.dart';
 import 'package:cake_wallet/exchange/trade_request.dart';
 import 'package:cake_wallet/exchange/exchange_pair.dart';
@@ -14,6 +13,7 @@ abstract class ExchangeProvider {
   ExchangeProviderDescription get description;
   bool get isAvailable;
   bool get isEnabled;
+  bool get supportsFixedRate;
 
   @override
   String toString() => title;
@@ -26,7 +26,7 @@ abstract class ExchangeProvider {
     required TradeRequest request,
     required bool isFixedRateMode});
   Future<Trade> findTradeById({required String id});
-  Future<double> calculateAmount({
+  Future<double> fetchRate({
     required CryptoCurrency from,
     required CryptoCurrency to,
     required double amount,

lib/exchange/morphtoken/morphtoken_exchange_provider.dart

@@ -66,6 +66,9 @@ class MorphTokenExchangeProvider extends ExchangeProvider {
   @override
   bool get isEnabled => true;
 
+  @override
+  bool get supportsFixedRate => false;
+
   @override
   ExchangeProviderDescription get description =>
       ExchangeProviderDescription.morphToken;
@@ -200,7 +203,7 @@ class MorphTokenExchangeProvider extends ExchangeProvider {
   }
 
   @override
-  Future<double> calculateAmount(
+  Future<double> fetchRate(
       {required CryptoCurrency from,
       required CryptoCurrency to,
       required double amount,

lib/exchange/sideshift/sideshift_exchange_provider.dart

@@ -12,7 +12,6 @@ import 'package:cw_core/crypto_currency.dart';
 import 'package:cake_wallet/exchange/trade_request.dart';
 import 'package:cake_wallet/exchange/trade.dart';
 import 'package:cake_wallet/exchange/limits.dart';
-import 'package:flutter/foundation.dart';
 import 'package:http/http.dart';
 
 class SideShiftExchangeProvider extends ExchangeProvider {
@@ -48,8 +47,7 @@ class SideShiftExchangeProvider extends ExchangeProvider {
 
     return supportedCurrencies
         .map((i) => supportedCurrencies
-            .map((k) => ExchangePair(from: i, to: k, reverse: true))
+            .map((k) => ExchangePair(from: i, to: k, reverse: true)))
-            .where((c) => c != null))
         .expand((i) => i)
         .toList();
   }
@@ -59,7 +57,7 @@ class SideShiftExchangeProvider extends ExchangeProvider {
       ExchangeProviderDescription.sideShift;
 
   @override
-  Future<double> calculateAmount(
+  Future<double> fetchRate(
       {required CryptoCurrency from,
       required CryptoCurrency to,
       required double amount,
@@ -81,9 +79,7 @@ class SideShiftExchangeProvider extends ExchangeProvider {
 
       if (amount > max) return 0.00;
 
-      final estimatedAmount = rate * amount;
+      return rate;
-
-      return estimatedAmount;
     } catch (_) {
       return 0.00;
     }
@@ -257,8 +253,7 @@ class SideShiftExchangeProvider extends ExchangeProvider {
     state = TradeState.deserialize(raw: status ?? 'created');
 
     final expiredAtRaw = responseJSON['expiresAtISO'] as String;
-    final expiredAt =
+    final expiredAt = DateTime.tryParse(expiredAtRaw)?.toLocal();
-        expiredAtRaw != null ? DateTime.parse(expiredAtRaw).toLocal() : null;
 
     return Trade(
       id: id,
@@ -278,6 +273,9 @@ class SideShiftExchangeProvider extends ExchangeProvider {
   @override
   bool get isEnabled => true;
 
+  @override
+  bool get supportsFixedRate => true;
+
   @override
   String get title => 'SideShift';
 

lib/exchange/simpleswap/simpleswap_exchange_provider.dart

@@ -20,8 +20,7 @@ class SimpleSwapExchangeProvider extends ExchangeProvider {
                 .where((i) => i != CryptoCurrency.zaddr)
                 .map((i) => CryptoCurrency.all
                     .where((i) => i != CryptoCurrency.zaddr)
-                    .map((k) => ExchangePair(from: i, to: k, reverse: true))
+                    .map((k) => ExchangePair(from: i, to: k, reverse: true)))
-                    .where((c) => c != null))
                 .expand((i) => i)
                 .toList());
 
@@ -37,7 +36,7 @@ class SimpleSwapExchangeProvider extends ExchangeProvider {
       ExchangeProviderDescription.simpleSwap;
 
   @override
-  Future<double> calculateAmount(
+  Future<double> fetchRate(
       {required CryptoCurrency from,
       required CryptoCurrency to,
       required double amount,
@@ -59,9 +58,9 @@ class SimpleSwapExchangeProvider extends ExchangeProvider {
       final uri = Uri.https(apiAuthority, getEstimatePath, params);
       final response = await get(uri);
 
-      if (response.body == null || response.body == "null") return 0.00;
+      if (response.body == "null") return 0.00;
       final data = json.decode(response.body) as String;
-      return double.parse(data);
+      return double.parse(data) / amount;
     } catch (_) {
       return 0.00;
     }
@@ -210,6 +209,9 @@ class SimpleSwapExchangeProvider extends ExchangeProvider {
   @override
   bool get isEnabled => true;
 
+  @override
+  bool get supportsFixedRate => false;
+
   @override
   String get title => 'SimpleSwap';
 

lib/exchange/xmrto/xmrto_exchange_provider.dart

@@ -48,6 +48,9 @@ class XMRTOExchangeProvider extends ExchangeProvider {
   @override
   bool get isEnabled => true;
 
+  @override
+  bool get supportsFixedRate => false;
+
   @override
   ExchangeProviderDescription get description =>
       ExchangeProviderDescription.xmrto;
@@ -191,7 +194,7 @@ class XMRTOExchangeProvider extends ExchangeProvider {
   }
 
   @override
-  Future<double> calculateAmount(
+  Future<double> fetchRate(
       {required CryptoCurrency from,
       required CryptoCurrency to,
       required double amount,

lib/store/settings_store.dart

@@ -115,6 +115,11 @@ abstract class SettingsStoreBase with Store {
         (BalanceDisplayMode mode) => sharedPreferences.setInt(
             PreferencesKey.currentBalanceDisplayModeKey, mode.serialize()));
 
+    reaction(
+            (_) => disableExchange,
+            (bool disableExchange) => sharedPreferences.setBool(
+            PreferencesKey.disableExchangeKey, disableExchange));
+
     this
         .nodes
         .observe((change) { 

lib/view_model/exchange/exchange_view_model.dart

@@ -44,7 +44,6 @@ abstract class ExchangeViewModelBase with Store {
   ExchangeViewModelBase(this.wallet, this.trades, this._exchangeTemplateStore,
       this.tradesStore, this._settingsStore, this.sharedPreferences)
     : _cryptoNumberFormat = NumberFormat(),
-      isReverse = false,
       isFixedRateMode = false,
       isReceiveAmountEntered = false,
       depositAmount = '',
@@ -112,7 +111,11 @@ abstract class ExchangeViewModelBase with Store {
     loadLimits();
     reaction(
       (_) => isFixedRateMode,
-      (Object _) => loadLimits());
+      (Object _) {
+        loadLimits();
+        _bestRate = 0;
+        _calculateBestRate();
+      });
   }
 
   final WalletBase wallet;
@@ -227,8 +230,6 @@ abstract class ExchangeViewModelBase with Store {
 
   Limits limits;
 
-  bool isReverse;
-
   NumberFormat _cryptoNumberFormat;
 
   final SettingsStore _settingsStore;
@@ -258,7 +259,6 @@ abstract class ExchangeViewModelBase with Store {
   @action
   Future<void> changeReceiveAmount({required String amount}) async {
     receiveAmount = amount;
-    isReverse = true;
 
     if (amount.isEmpty) {
       depositAmount = '';
@@ -283,7 +283,6 @@ abstract class ExchangeViewModelBase with Store {
   @action
   Future<void> changeDepositAmount({required String amount}) async {
     depositAmount = amount;
-    isReverse = false;
 
     if (amount.isEmpty) {
       depositAmount = '';
@@ -311,12 +310,13 @@ abstract class ExchangeViewModelBase with Store {
 
     final result = await Future.wait<double>(
         _tradeAvailableProviders
-            .map((element) => element.calculateAmount(
+            .where((element) => !isFixedRateMode || element.supportsFixedRate)
+            .map((element) => element.fetchRate(
                 from: depositCurrency,
                 to: receiveCurrency,
                 amount: amount,
                 isFixedRateMode: isFixedRateMode,
-                isReceiveAmount: false))
+                isReceiveAmount: isFixedRateMode))
     );
 
     _sortedAvailableProviders.clear();
@@ -324,7 +324,7 @@ abstract class ExchangeViewModelBase with Store {
     for (int i=0;i<result.length;i++) {
       if (result[i] != 0) {
         /// add this provider as its valid for this trade
-        _sortedAvailableProviders[result[i] / amount] = _tradeAvailableProviders[i];
+        _sortedAvailableProviders[result[i]] = _tradeAvailableProviders[i];
       }
     }
     if (_sortedAvailableProviders.isNotEmpty) {
@@ -401,7 +401,7 @@ abstract class ExchangeViewModelBase with Store {
             settleAddress: receiveAddress,
             refundAddress: depositAddress,
           );
-          amount = depositAmount;
+          amount = isFixedRateMode ? receiveAmount : depositAmount;
         }
 
         if (provider is SimpleSwapExchangeProvider) {
@@ -412,7 +412,7 @@ abstract class ExchangeViewModelBase with Store {
             address: receiveAddress,
             refundAddress: depositAddress,
           );
-          amount = depositAmount;
+          amount = isFixedRateMode ? receiveAmount : depositAmount;
         }
 
         if (provider is XMRTOExchangeProvider) {
@@ -424,7 +424,7 @@ abstract class ExchangeViewModelBase with Store {
               address: receiveAddress,
               refundAddress: depositAddress,
               isBTCRequest: isReceiveAmountEntered);
-          amount = depositAmount;
+          amount = isFixedRateMode ? receiveAmount : depositAmount;
         }
 
         if (provider is ChangeNowExchangeProvider) {
@@ -435,8 +435,8 @@ abstract class ExchangeViewModelBase with Store {
               toAmount: receiveAmount.replaceAll(',', '.'),
               refundAddress: depositAddress,
               address: receiveAddress,
-              isReverse: isReverse);
+              isReverse: isFixedRateMode);
-          amount = isReverse ? receiveAmount : depositAmount;
+          amount = isFixedRateMode ? receiveAmount : depositAmount;
         }
 
         if (provider is MorphTokenExchangeProvider) {
@@ -446,13 +446,13 @@ abstract class ExchangeViewModelBase with Store {
               amount: depositAmount.replaceAll(',', '.'),
               refundAddress: depositAddress,
               address: receiveAddress);
-          amount = depositAmount;
+          amount = isFixedRateMode ? receiveAmount : depositAmount;
         }
 
         amount = amount.replaceAll(',', '.');
 
         if (limitsState is LimitsLoadedSuccessfully) {
-          if (double.parse(amount) < limits.min!) {
+          if (limits.max != null && double.parse(amount) < limits.min!) {
             continue;
           } else if (limits.max != null && double.parse(amount) > limits.max!) {
             continue;