Fix transaction amount conversions

cw_ethereum/lib/ethereum_client.dart

@@ -97,6 +97,7 @@ class EthereumClient {
     required int gas,
     required EthereumTransactionPriority priority,
     required CryptoCurrency currency,
+    required int exponent,
     String? contractAddress,
   }) async {
     assert(currency == CryptoCurrency.eth || contractAddress != null);
@@ -115,7 +116,7 @@ class EthereumClient {
 
     final signedTransaction = await _client!.signTransaction(privateKey, transaction);
 
-    final estimatedGas;
+    final BigInt estimatedGas;
     final Function _sendTransaction;
 
     if (_isEthereum) {
@@ -129,14 +130,10 @@ class EthereumClient {
         address: EthereumAddress.fromHex(contractAddress!),
       );
 
-      final originalAmount = BigInt.parse(amount) / BigInt.from(pow(10, 18));
-      final int exponent = (await erc20.decimals()).toInt();
-      final _amount = BigInt.from(originalAmount * pow(10, exponent));
-
       _sendTransaction = () async {
         await erc20.transfer(
           EthereumAddress.fromHex(toAddress),
-          _amount,
+          BigInt.parse(amount),
           credentials: privateKey,
         );
       };
@@ -147,6 +144,7 @@ class EthereumClient {
       amount: amount,
       fee: estimatedGas * price.getInWei,
       sendTransaction: _sendTransaction,
+      exponent: exponent,
     );
   }
 

cw_ethereum/lib/ethereum_exceptions.dart

@@ -1,8 +1,10 @@
+import 'package:cw_core/crypto_currency.dart';
+
 class EthereumTransactionCreationException implements Exception {
   final String exceptionMessage;
 
-  EthereumTransactionCreationException(
-      {this.exceptionMessage = 'Wrong balance. Not enough Ether on your balance.'});
+  EthereumTransactionCreationException(CryptoCurrency currency) :
+    this.exceptionMessage = 'Wrong balance. Not enough ${currency.title} on your balance.';
 
   @override
   String toString() => exceptionMessage;

cw_ethereum/lib/ethereum_formatter.dart

@@ -1,5 +1,3 @@
-import 'dart:math';
-
 import 'package:intl/intl.dart';
 
 const ethereumAmountLength = 12;
@@ -17,10 +15,9 @@ class EthereumFormatter {
     }
   }
 
-  static int parseEthereumBigIntAmount(BigInt amount) {
+  static double parseEthereumAmountToDouble(int amount) {
     try {
-      double result = amount / BigInt.from(pow(10, 18 - ethereumAmountLength));
-      return result.toInt();
+      return amount / ethereumAmountDivider;
     } catch (_) {
       return 0;
     }

cw_ethereum/lib/ethereum_wallet.dart

@@ -147,30 +147,33 @@ abstract class EthereumWalletBase
     final hasMultiDestination = outputs.length > 1;
     final _erc20Balance = balance[_credentials.currency]!;
     BigInt totalAmount = BigInt.zero;
-    BigInt amountToEthereumMultiplier = BigInt.from(pow(10, 18 - ethereumAmountLength));
+    int exponent =
+        _credentials.currency is Erc20Token ? (_credentials.currency as Erc20Token).decimal : 18;
+    BigInt amountToEthereumMultiplier = BigInt.from(pow(10, exponent));
 
     if (hasMultiDestination) {
       if (outputs.any((item) => item.sendAll || (item.formattedCryptoAmount ?? 0) <= 0)) {
-        throw EthereumTransactionCreationException();
+        throw EthereumTransactionCreationException(_credentials.currency);
       }
 
-      totalAmount =
-          BigInt.from(outputs.fold(0, (acc, value) => acc + (value.formattedCryptoAmount ?? 0))) *
-              amountToEthereumMultiplier;
+      final totalOriginalAmount = EthereumFormatter.parseEthereumAmountToDouble(
+          outputs.fold(0, (acc, value) => acc + (value.formattedCryptoAmount ?? 0)));
+      totalAmount = BigInt.from(totalOriginalAmount) * amountToEthereumMultiplier;
 
       if (_erc20Balance.balance < totalAmount) {
-        throw EthereumTransactionCreationException();
+        throw EthereumTransactionCreationException(_credentials.currency);
       }
     } else {
       final output = outputs.first;
       final BigInt allAmount = _erc20Balance.balance - BigInt.from(feeRate(_credentials.priority!));
+      final totalOriginalAmount =
+          EthereumFormatter.parseEthereumAmountToDouble(output.formattedCryptoAmount ?? 0);
       totalAmount = output.sendAll
           ? allAmount
-          : BigInt.from(output.formattedCryptoAmount ?? 0) * amountToEthereumMultiplier;
+          : BigInt.from(totalOriginalAmount) * amountToEthereumMultiplier;
 
-      if ((output.sendAll && _erc20Balance.balance < totalAmount) ||
-          (!output.sendAll && _erc20Balance.balance <= BigInt.zero)) {
-        throw EthereumTransactionCreationException();
+      if (_erc20Balance.balance < totalAmount) {
+        throw EthereumTransactionCreationException(_credentials.currency);
       }
     }
 
@@ -181,6 +184,7 @@ abstract class EthereumWalletBase
       gas: _priorityFees[_credentials.priority!.raw],
       priority: _credentials.priority!,
       currency: _credentials.currency,
+      exponent: exponent,
       contractAddress: _credentials.currency is Erc20Token
           ? (_credentials.currency as Erc20Token).contractAddress
           : null,

cw_ethereum/lib/pending_ethereum_transaction.dart

@@ -1,31 +1,32 @@
+import 'dart:math';
 import 'dart:typed_data';
 
 import 'package:cw_core/pending_transaction.dart';
 import 'package:web3dart/crypto.dart';
-import 'package:web3dart/web3dart.dart';
 
 class PendingEthereumTransaction with PendingTransaction {
   final Function sendTransaction;
   final Uint8List signedTransaction;
   final BigInt fee;
   final String amount;
+  final int exponent;
 
   PendingEthereumTransaction({
     required this.sendTransaction,
     required this.signedTransaction,
     required this.fee,
     required this.amount,
+    required this.exponent,
   });
 
   @override
-  String get amountFormatted =>
-      EtherAmount.inWei(BigInt.parse(amount)).getValueInUnit(EtherUnit.ether).toString();
+  String get amountFormatted => (BigInt.parse(amount) / BigInt.from(pow(10, exponent))).toString();
 
   @override
   Future<void> commit() async => await sendTransaction();
 
   @override
-  String get feeFormatted => EtherAmount.inWei(fee).getValueInUnit(EtherUnit.ether).toString();
+  String get feeFormatted => (fee / BigInt.from(pow(10, 18))).toString();
 
   @override
   String get hex => bytesToHex(signedTransaction, include0x: true);