Validate swap amounts before creating trade (#3296)

lib/view_model/exchange/exchange_view_model.dart

@@ -1025,6 +1025,39 @@ abstract class ExchangeViewModelBase extends WalletChangeListenerViewModel with
 
   @action
   Future<void> createTrade() async {
+    final depositAmountValue =
+        double.tryParse(_depositAmount.replaceAll(',', '.')) ?? 0.0;
+
+    final receiveAmountValue =
+        double.tryParse(_receiveAmount.replaceAll(',', '.')) ?? 0.0;
+
+    if (depositAmountValue <= 0 || receiveAmountValue <= 0) {
+      ExchangeProviderLogger.logError(
+        provider: forcedProvider?.description ?? bestRateProvider?.description,
+        function: 'createTrade',
+        error: 'Invalid swap amount: deposit=$_depositAmount receive=$_receiveAmount',
+        requestData: {
+          'from': depositCurrency.title,
+          'to': receiveCurrency.title,
+          'fromAmount': _depositAmount,
+          'toAmount': _receiveAmount,
+          'isFixedRateMode': isFixedRateMode,
+          'forcedProvider': forcedProvider?.title,
+          'bestRateProvider': bestRateProvider?.title,
+        },
+      );
+
+      final invalidAmountError = depositAmountValue <= 0
+          ? '$depositAmountValue is not a valid amount for depositAmount'
+          : '$receiveAmountValue is not a valid amount for receiveAmount';
+
+      tradeState = TradeIsCreatedFailure(
+        title: S.current.trade_not_created,
+        error: invalidAmountError,
+      );
+      return;
+    }
+
     if (isSendAllEnabled) {
       await calculateDepositAllAmount();
       final amount = double.tryParse(_depositAmount);