CAKE-278 | fixed calculating estimated amount when receive amount is entered; fixed applyTemplate() method in the exchange_page.dart and reset() method in the exchange_view_model.dart

lib/exchange/changenow/changenow_exchange_provider.dart

@@ -173,8 +173,32 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
       double amount,
       bool isFixedRateMode,
       bool isReceiveAmount}) async {
-    final url = isFixedRateMode
-        ? apiUri +
+    if (isReceiveAmount && isFixedRateMode) {
+      final url = apiUri + _marketInfoUriSufix + _fixedRateUriSufix + apiKey;
+      final response = await get(url);
+      final responseJSON = json.decode(response.body) as List<dynamic>;
+      var rate = 0.0;
+      var fee = 0.0;
+
+      for (var elem in responseJSON) {
+        final elemFrom = elem["from"] as String;
+        final elemTo = elem["to"] as String;
+
+        if ((elemFrom == to.toString().toLowerCase()) &&
+            (elemTo == from.toString().toLowerCase())) {
+          rate = elem["rate"] as double;
+          fee = elem["minerFee"] as double;
+          break;
+        }
+      }
+
+      final estimatedAmount = (amount == 0.0)||(rate == 0.0) ? 0.0
+          : (amount + fee)/rate;
+
+      return estimatedAmount;
+    } else {
+      final url = isFixedRateMode
+          ? apiUri +
           _exchangeAmountUriSufix +
           _fixedRateUriSufix +
           amount.toString() +
@@ -183,17 +207,18 @@ class ChangeNowExchangeProvider extends ExchangeProvider {
           '_' +
           to.toString() +
           '?api_key=' + apiKey
-        : apiUri +
+          : apiUri +
           _exchangeAmountUriSufix +
           amount.toString() +
           '/' +
           from.toString() +
           '_' +
           to.toString();
-    final response = await get(url);
-    final responseJSON = json.decode(response.body) as Map<String, dynamic>;
-    final estimatedAmount = responseJSON['estimatedAmount'] as double;
+      final response = await get(url);
+      final responseJSON = json.decode(response.body) as Map<String, dynamic>;
+      final estimatedAmount = responseJSON['estimatedAmount'] as double;
 
-    return estimatedAmount;
+      return estimatedAmount;
+    }
   }
 }

lib/src/screens/exchange/exchange_page.dart

@@ -480,17 +480,9 @@ class ExchangePage extends BasePage {
         currency: CryptoCurrency.fromString(template.receiveCurrency));
 
     switch (template.provider) {
-      case 'XMR.TO':
-        exchangeViewModel.changeProvider(
-            provider: exchangeViewModel.providerList[0]);
-        break;
       case 'ChangeNOW':
         exchangeViewModel.changeProvider(
-            provider: exchangeViewModel.providerList[1]);
-        break;
-      case 'MorphToken':
-        exchangeViewModel.changeProvider(
-            provider: exchangeViewModel.providerList[2]);
+            provider: exchangeViewModel.providerList[0]);
         break;
     }
 
@@ -498,6 +490,7 @@ class ExchangePage extends BasePage {
     exchangeViewModel.depositAddress = template.depositAddress;
     exchangeViewModel.receiveAddress = template.receiveAddress;
     exchangeViewModel.isReceiveAmountEntered = false;
+    exchangeViewModel.isFixedRateMode = false;
   }
 
   void _setReactions(
@@ -670,12 +663,11 @@ class ExchangePage extends BasePage {
             builder: (BuildContext context) {
               return AlertWithTwoActions(
                   alertTitle: S.of(context).exchange,
-                  alertContent: 'You will be able to enter receive amount when fixed rate is checked. Do you want to check fixed rate?', //FIXME
+                  alertContent: 'You will be able to enter receive amount when fixed rate mode is checked. Do you want to switch to fixed rate mode?', //FIXME
                   leftButtonText: S.of(context).cancel,
                   rightButtonText: S.of(context).ok,
                   actionLeftButton: () {
                     FocusScope.of(context).unfocus();
-                    receiveAmountController.text = '';
                     Navigator.of(context).pop();
                   },
                   actionRightButton: () {

lib/view_model/exchange/exchange_view_model.dart

@@ -301,11 +301,10 @@ abstract class ExchangeViewModelBase with Store {
 
   @action
   void reset() {
+    _initialPairBasedOnWallet();
     isReceiveAmountEntered = false;
     depositAmount = '';
     receiveAmount = '';
-    depositCurrency = CryptoCurrency.xmr;
-    receiveCurrency = CryptoCurrency.btc;
     depositAddress = depositCurrency == wallet.currency ? wallet.address : '';
     receiveAddress = receiveCurrency == wallet.currency ? wallet.address : '';
     isDepositAddressEnabled = !(depositCurrency == wallet.currency);