CW-1069-implement-deuro-dapp-support (#2304)

* feat: started dEuro Savings integration

* fix: merge conflict regarding theming

* feat: Add dEuro Savings Screen

* feat: Change DEuro Savings UI

* feat: Complete DEuro Savings integration with UI enhancements and transaction support

* style: remove forgotten print statements

* feat: localize dEuro subtitle

* feat: add approval flow and priority handling to DEuro Savings integration

- Introduced approval flow for DEuro Savings to enable token approvals.
- Added priority handling for deposit and withdrawal operations.
- Updated UI to support approval state and interactions.
- Localized new strings for multiple languages.
- Enhanced transaction handling with separate approval and commit actions.

* feat: add support for ERC20 token approval transactions

- Introduced `signApprovalTransaction` and `createApprovalTransaction` methods.
- Added handling for infinite approvals.
- Implemented encoding for approval transaction data.
- Enhanced transaction creation flow with approval-specific functionality.

* Update UI

* feat: enhance DEuro Savings logic and UI with computed property and fix gradient background

* feat: localize transaction confirmation content for DEuro Savings

* feat: enable interest collection for DEuro Savings with localized support

* fix reformatting [skip ci]

---------

Co-authored-by: tuxsudo <tuxsudo@tux.pizza>
Co-authored-by: OmarHatem <omarh.ismail1@gmail.com>

cw_evm/lib/evm_chain_client.dart

@@ -76,7 +76,7 @@ abstract class EVMChainClient {
   Future<int> getGasUnitPrice() async {
     try {
       final gasPrice = await _client!.getGasPrice();
-    
+
       return gasPrice.getInWei.toInt();
     } catch (_) {
       return 0;
@@ -101,6 +101,7 @@ abstract class EVMChainClient {
     String? contractAddress,
     EtherAmount? gasPrice,
     EtherAmount? maxFeePerGas,
+    Uint8List? data,
   }) async {
     try {
       if (contractAddress == null) {
@@ -124,7 +125,7 @@ abstract class EVMChainClient {
         final gasEstimate = await _client!.estimateGas(
           sender: senderAddress,
           to: EthereumAddress.fromHex(contractAddress),
-          data: transfer.encodeCall([
+          data: data ?? transfer.encodeCall([
             toAddress,
             value.getInWei,
           ]),
@@ -137,6 +138,21 @@ abstract class EVMChainClient {
     }
   }
 
+  Uint8List getEncodedDataForApprovalTransaction({
+    required EthereumAddress toAddress,
+    required EtherAmount value,
+    required EthereumAddress contractAddress,
+  }) {
+    final contract = DeployedContract(ethereumContractAbi, contractAddress);
+
+    final approve = contract.function('approve');
+
+    return approve.encodeCall([
+      toAddress,
+      value.getInWei,
+    ]);
+  }
+
   Future<PendingEVMChainTransaction> signTransaction({
     required Credentials privateKey,
     required String toAddress,
@@ -198,6 +214,50 @@ abstract class EVMChainClient {
     );
   }
 
+  Future<PendingEVMChainTransaction> signApprovalTransaction({
+    required Credentials privateKey,
+    required String spender,
+    required BigInt amount,
+    required BigInt gasFee,
+    required int estimatedGasUnits,
+    required int maxFeePerGas,
+    required EVMChainTransactionPriority priority,
+    required int exponent,
+    required String contractAddress,
+  }) async {
+
+    final Transaction transaction = createTransaction(
+      from: privateKey.address,
+      to: EthereumAddress.fromHex(contractAddress),
+      maxPriorityFeePerGas: EtherAmount.fromInt(EtherUnit.gwei, priority.tip),
+      amount: EtherAmount.zero(),
+      maxGas: estimatedGasUnits,
+      maxFeePerGas: EtherAmount.fromInt(EtherUnit.wei, maxFeePerGas),
+    );
+
+    final erc20 = ERC20(
+      client: _client!,
+      address: EthereumAddress.fromHex(contractAddress),
+      chainId: chainId,
+    );
+
+    final signedTransaction = await erc20.approve(
+      EthereumAddress.fromHex(spender),
+      amount,
+      credentials: privateKey,
+      transaction: transaction,
+    );
+
+    return PendingEVMChainTransaction(
+      signedTransaction: prepareSignedTransactionForSending(signedTransaction),
+      amount: amount.toString(),
+      fee: gasFee,
+      sendTransaction: () => sendTransaction(signedTransaction),
+      exponent: exponent,
+      isInfiniteApproval: amount.toRadixString(16) == 'ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff',
+    );
+  }
+
   Transaction createTransaction({
     required EthereumAddress from,
     required EthereumAddress to,

cw_evm/lib/evm_chain_wallet.dart

@@ -2,6 +2,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 import 'dart:math';
+import 'dart:typed_data';
 
 import 'package:bip32/bip32.dart' as bip32;
 import 'package:bip39/bip39.dart' as bip39;
@@ -255,6 +256,7 @@ abstract class EVMChainWalletBase
     required String? contractAddress,
     required String receivingAddressHex,
     required TransactionPriority priority,
+    Uint8List? data,
   }) async {
     try {
       if (priority is EVMChainTransactionPriority) {
@@ -276,6 +278,7 @@ abstract class EVMChainWalletBase
           gasPrice: EtherAmount.fromInt(EtherUnit.wei, gasPrice),
           toAddress: EthereumAddress.fromHex(receivingAddressHex),
           maxFeePerGas: EtherAmount.fromInt(EtherUnit.wei, maxFeePerGas),
+          data: data,
         );
 
         final totalGasFee = estimatedGas * maxFeePerGas;
@@ -478,6 +481,43 @@ abstract class EVMChainWalletBase
     return pendingEVMChainTransaction;
   }
 
+  Future<PendingTransaction> createApprovalTransaction(
+      BigInt amount,
+      String spender,
+      CryptoCurrency token,
+      EVMChainTransactionPriority priority) async {
+    final CryptoCurrency transactionCurrency =
+        balance.keys.firstWhere((element) => element.title == token.title);
+    assert(transactionCurrency is Erc20Token);
+
+    final data = _client.getEncodedDataForApprovalTransaction(
+      contractAddress: EthereumAddress.fromHex(
+          (transactionCurrency as Erc20Token).contractAddress),
+      value: EtherAmount.fromBigInt(EtherUnit.wei, amount),
+      toAddress: EthereumAddress.fromHex(spender),
+    );
+
+    final gasFeesModel = await calculateActualEstimatedFeeForCreateTransaction(
+      amount: amount,
+      receivingAddressHex: spender,
+      priority: priority,
+      contractAddress: transactionCurrency.contractAddress,
+      data: data,
+    );
+
+    return _client.signApprovalTransaction(
+      privateKey: _evmChainPrivateKey,
+      spender: spender,
+      amount: amount,
+      priority: priority,
+      gasFee: BigInt.from(gasFeesModel.estimatedGasFee),
+      maxFeePerGas: gasFeesModel.maxFeePerGas,
+      estimatedGasUnits: gasFeesModel.estimatedGasUnits,
+      exponent: transactionCurrency.decimal,
+      contractAddress: transactionCurrency.contractAddress,
+    );
+  }
+
   Future<void> _updateTransactions() async {
     try {
       if (_isTransactionUpdating) {

cw_evm/lib/pending_evm_chain_transaction.dart

@@ -11,6 +11,7 @@ class PendingEVMChainTransaction with PendingTransaction {
   final BigInt fee;
   final String amount;
   final int exponent;
+  final bool isInfiniteApproval;
 
   PendingEVMChainTransaction({
     required this.sendTransaction,
@@ -18,10 +19,12 @@ class PendingEVMChainTransaction with PendingTransaction {
     required this.fee,
     required this.amount,
     required this.exponent,
+    this.isInfiniteApproval = false,
   });
 
   @override
   String get amountFormatted {
+    if (isInfiniteApproval) return "∞";
     final _amount = (BigInt.parse(amount) / BigInt.from(pow(10, exponent))).toString();
     return _amount.substring(0, min(10, _amount.length));
   }