From 73743932aec6db5b38d360578a60227988ffb7b8 Mon Sep 17 00:00:00 2001
From: OmarHatem <omarh.ismail1@gmail.com>
Date: Tue, 6 Jun 2023 22:32:36 +0300
Subject: [PATCH] Add initial flow for transactions subscription

---
 cw_ethereum/lib/ethereum_client.dart          | 48 +++++++++++++++++++
 .../lib/ethereum_transaction_history.dart     |  4 +-
 cw_ethereum/lib/ethereum_wallet.dart          | 14 ++++--
 3 files changed, 61 insertions(+), 5 deletions(-)

diff --git a/cw_ethereum/lib/ethereum_client.dart b/cw_ethereum/lib/ethereum_client.dart
index 7390e6619..f36288ee6 100644
--- a/cw_ethereum/lib/ethereum_client.dart
+++ b/cw_ethereum/lib/ethereum_client.dart
@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:math';
 
 import 'package:cw_core/crypto_currency.dart';
@@ -20,6 +21,7 @@ class EthereumClient {
   Map<CryptoCurrency, String> get erc20Currencies => _erc20Currencies;
 
   Web3Client? _client;
+  StreamSubscription<Transfer>? subscription;
 
   bool connect(Node node) {
     try {
@@ -31,6 +33,47 @@ class EthereumClient {
     }
   }
 
+  void setListeners(EthereumAddress userAddress, Function(FilterEvent) onNewTransaction) async {
+    // final String abi = await rootBundle.loadString("assets/abi_json/erc20_abi.json");
+    // final contractAbi = ContractAbi.fromJson(abi, "ERC20");
+    //
+    // final contract = DeployedContract(
+    //   contractAbi,
+    //   EthereumAddress.fromHex("0xf451659CF5688e31a31fC3316efbcC2339A490Fb"),
+    // );
+    //
+    // final transferEvent = contract.event('Transfer');
+    // // listen for the Transfer event when it's emitted by the contract above
+    // final subscription = _client!
+    //     .events(FilterOptions.events(contract: contract, event: transferEvent))
+    //     .take(1)
+    //     .listen((event) {
+    //   final decoded = transferEvent.decodeResults(event.topics ?? [], event.data ?? '');
+    //
+    //   final from = decoded[0] as EthereumAddress;
+    //   final to = decoded[1] as EthereumAddress;
+    //   final value = decoded[2] as BigInt;
+    //
+    //   print('$from sent $value MetaCoins to $to');
+    // });
+
+    // final eventFilter = FilterOptions(address: userAddress);
+    //
+    // _client!.events(eventFilter).listen((event) {
+    //     print("!!!!!!!!!!!!!!!!!!");
+    //     print('Address ${event.address} data ${event.data} tx hash ${event.transactionHash}!');
+    //     onNewTransaction(event);
+    // });
+
+    // final erc20 = Erc20(client: _client!, address: userAddress);
+    //
+    // subscription = erc20.transferEvents().take(1).listen((event) {
+    //   print("!!!!!!!!!!!!!!!!!!");
+    //   print('${event.from} sent ${event.value} MetaCoins to ${event.to}!');
+    //   onNewTransaction(event);
+    // });
+  }
+
   Future<EtherAmount> getBalance(EthereumAddress address) async =>
       await _client!.getBalance(address);
 
@@ -186,6 +229,11 @@ I/flutter ( 4474): Gas Used: 53000
     return erc20Balances;
   }
 
+  void stop() {
+    subscription?.cancel();
+    _client?.dispose();
+  }
+
 // Future<bool> sendERC20Token(
 //     EthereumAddress to, CryptoCurrency erc20Currency, BigInt amount) async {
 //   if (_erc20Currencies[erc20Currency] == null) {
diff --git a/cw_ethereum/lib/ethereum_transaction_history.dart b/cw_ethereum/lib/ethereum_transaction_history.dart
index faf04db20..8a5825c73 100644
--- a/cw_ethereum/lib/ethereum_transaction_history.dart
+++ b/cw_ethereum/lib/ethereum_transaction_history.dart
@@ -15,7 +15,9 @@ abstract class EthereumTransactionHistoryBase
   }
 
   @override
-  Future<void> save() async {}
+  Future<void> save() async {
+    // TODO: implement
+  }
 
   @override
   void addOne(EthereumTransactionInfo transaction) =>
diff --git a/cw_ethereum/lib/ethereum_wallet.dart b/cw_ethereum/lib/ethereum_wallet.dart
index 1a4b57e63..ae440bdcf 100644
--- a/cw_ethereum/lib/ethereum_wallet.dart
+++ b/cw_ethereum/lib/ethereum_wallet.dart
@@ -96,7 +96,9 @@ abstract class EthereumWalletBase
   }
 
   @override
-  void close() {}
+  void close() {
+    _client.stop();
+  }
 
   @action
   @override
@@ -110,6 +112,7 @@ abstract class EthereumWalletBase
         throw Exception("Ethereum Node connection failed");
       }
 
+      _client.setListeners(_privateKey.address, _onNewTransaction);
       _updateBalance();
 
       syncStatus = ConnectedSyncStatus();
@@ -199,9 +202,7 @@ abstract class EthereumWalletBase
           (timer) async => _priorityFees = await _client.getEstimatedGasForPriorities());
 
       syncStatus = SyncedSyncStatus();
-    } catch (e, stacktrace) {
-      print(stacktrace);
-      print(e.toString());
+    } catch (e) {
       syncStatus = FailedSyncStatus();
     }
   }
@@ -270,4 +271,9 @@ abstract class EthereumWalletBase
   Future<void>? updateBalance() => null;
 
   List<CryptoCurrency> get erc20Currencies => _client.erc20Currencies.keys.toList();
+
+  void _onNewTransaction(FilterEvent event) {
+    _updateBalance();
+    // TODO: Add in transaction history
+  }
 }