From b79ef988c80a6e7000b2d906b49791a69e6733f7 Mon Sep 17 00:00:00 2001
From: Serhii <borodenko.sv@gmail.com>
Date: Wed, 25 Dec 2024 21:27:28 +0200
Subject: [PATCH] Cw 868 fix false synchronised status when the socket
 connection fails due to network issues (#1892)

* prevent setting Synced status when the connection is lost

* fallback for UTXO fetch failures

* minor fix
---
 cw_bitcoin/lib/electrum.dart        |  4 +-
 cw_bitcoin/lib/electrum_wallet.dart | 71 +++++++++++++++++++++++++----
 2 files changed, 64 insertions(+), 11 deletions(-)

diff --git a/cw_bitcoin/lib/electrum.dart b/cw_bitcoin/lib/electrum.dart
index 4fc4c1ad8..1f5c369e3 100644
--- a/cw_bitcoin/lib/electrum.dart
+++ b/cw_bitcoin/lib/electrum.dart
@@ -235,7 +235,7 @@ class ElectrumClient {
         return [];
       });
 
-  Future<List<Map<String, dynamic>>> getListUnspent(String scriptHash) async {
+  Future<List<Map<String, dynamic>>?> getListUnspent(String scriptHash) async {
     final result = await call(method: 'blockchain.scripthash.listunspent', params: [scriptHash]);
 
     if (result is List) {
@@ -248,7 +248,7 @@ class ElectrumClient {
       }).toList();
     }
 
-    return [];
+    return null;
   }
 
   Future<List<Map<String, dynamic>>> getMempool(String scriptHash) =>
diff --git a/cw_bitcoin/lib/electrum_wallet.dart b/cw_bitcoin/lib/electrum_wallet.dart
index 64eafb021..eae830db1 100644
--- a/cw_bitcoin/lib/electrum_wallet.dart
+++ b/cw_bitcoin/lib/electrum_wallet.dart
@@ -478,6 +478,7 @@ abstract class ElectrumWalletBase
       if (alwaysScan == true) {
         _setListeners(walletInfo.restoreHeight);
       } else {
+        if (syncStatus is LostConnectionSyncStatus) return;
         syncStatus = SyncedSyncStatus();
       }
     } catch (e, stacktrace) {
@@ -1361,6 +1362,10 @@ abstract class ElectrumWalletBase
   Future<void> updateAllUnspents() async {
     List<BitcoinUnspent> updatedUnspentCoins = [];
 
+    final previousUnspentCoins = List<BitcoinUnspent>.from(unspentCoins.where((utxo) =>
+    utxo.bitcoinAddressRecord.type != SegwitAddresType.mweb &&
+        utxo.bitcoinAddressRecord is! BitcoinSilentPaymentAddressRecord));
+
     if (hasSilentPaymentsScanning) {
       // Update unspents stored from scanned silent payment transactions
       transactionHistory.transactions.values.forEach((tx) {
@@ -1377,13 +1382,27 @@ abstract class ElectrumWalletBase
       if (addr is! BitcoinSilentPaymentAddressRecord) addr.balance = 0;
     });
 
-    await Future.wait(walletAddresses.allAddresses
+    final addressFutures = walletAddresses.allAddresses
         .where((element) => element.type != SegwitAddresType.mweb)
-        .map((address) async {
-      updatedUnspentCoins.addAll(await fetchUnspent(address));
-    }));
+        .map((address) => fetchUnspent(address))
+        .toList();
 
-    unspentCoins = updatedUnspentCoins;
+    final results = await Future.wait(addressFutures);
+    final failedCount = results.where((result) => result == null).length;
+
+    if (failedCount == 0) {
+      for (final result in results) {
+        updatedUnspentCoins.addAll(result!);
+      }
+      unspentCoins = updatedUnspentCoins;
+    } else {
+      unspentCoins = handleFailedUtxoFetch(
+        failedCount: failedCount,
+        previousUnspentCoins: previousUnspentCoins,
+        updatedUnspentCoins: updatedUnspentCoins,
+        results: results,
+      );
+    }
 
     final currentWalletUnspentCoins =
         unspentCoinsInfo.values.where((element) => element.walletId == id);
@@ -1396,6 +1415,38 @@ abstract class ElectrumWalletBase
     await _refreshUnspentCoinsInfo();
   }
 
+  List<BitcoinUnspent> handleFailedUtxoFetch({
+    required int failedCount,
+    required List<BitcoinUnspent> previousUnspentCoins,
+    required List<BitcoinUnspent> updatedUnspentCoins,
+    required List<List<BitcoinUnspent>?> results,
+  }) {
+
+    if (failedCount == results.length) {
+      printV("All UTXOs failed to fetch, falling back to previous UTXOs");
+      return previousUnspentCoins;
+    }
+
+    final successfulUtxos = <BitcoinUnspent>[];
+    for (final result in results) {
+      if (result != null) {
+        successfulUtxos.addAll(result);
+      }
+    }
+
+    if (failedCount > 0 && successfulUtxos.isEmpty) {
+      printV("Some UTXOs failed, but no successful UTXOs, falling back to previous UTXOs");
+      return previousUnspentCoins;
+    }
+
+    if (failedCount > 0) {
+      printV("Some UTXOs failed, updating with successful UTXOs");
+      updatedUnspentCoins.addAll(successfulUtxos);
+    }
+
+    return updatedUnspentCoins;
+  }
+
   Future<void> updateCoins(List<BitcoinUnspent> newUnspentCoins) async {
     if (newUnspentCoins.isEmpty) {
       return;
@@ -1427,15 +1478,17 @@ abstract class ElectrumWalletBase
   @action
   Future<void> updateUnspentsForAddress(BitcoinAddressRecord address) async {
     final newUnspentCoins = await fetchUnspent(address);
-    await updateCoins(newUnspentCoins);
+    await updateCoins(newUnspentCoins ?? []);
   }
 
   @action
-  Future<List<BitcoinUnspent>> fetchUnspent(BitcoinAddressRecord address) async {
-    List<Map<String, dynamic>> unspents = [];
+  Future<List<BitcoinUnspent>?> fetchUnspent(BitcoinAddressRecord address) async {
     List<BitcoinUnspent> updatedUnspentCoins = [];
 
-    unspents = await electrumClient.getListUnspent(address.getScriptHash(network));
+    final unspents = await electrumClient.getListUnspent(address.getScriptHash(network));
+
+    // Failed to fetch unspents
+    if (unspents == null) return null;
 
     await Future.wait(unspents.map((unspent) async {
       try {