detect hogex inputs and only require 6 confs if so (#2786)

cw_bitcoin/lib/bitcoin_unspent.dart

@@ -25,6 +25,7 @@ class BitcoinUnspent extends Unspent {
   }
 
   final BaseBitcoinAddressRecord bitcoinAddressRecord;
+  bool? isPegOut;
 }
 
 class BitcoinSilentPaymentsUnspent extends BitcoinUnspent {

cw_bitcoin/lib/electrum_transaction_info.dart

@@ -25,6 +25,7 @@ class ElectrumTransactionBundle {
 class ElectrumTransactionInfo extends TransactionInfo {
   List<BitcoinSilentPaymentsUnspent>? unspents;
   bool isReceivedSilentPayment;
+  bool isHogEx;
 
   ElectrumTransactionInfo(
     this.type, {
@@ -42,6 +43,7 @@ class ElectrumTransactionInfo extends TransactionInfo {
     String? to,
     this.unspents,
     this.isReceivedSilentPayment = false,
+    this.isHogEx = false,
     Map<String, dynamic>? additionalInfo,
   }) {
     this.id = id;
@@ -174,6 +176,15 @@ class ElectrumTransactionInfo extends TransactionInfo {
       amount = receivedAmounts.reduce((a, b) => a + b);
     }
 
+    // MWEB HogEx
+    final isHogExTx = (BtcTransaction tx) {
+      if (tx.inputs.isEmpty || tx.inputs.first.txIndex > 0 || tx.outputs.isEmpty)
+        return false;
+      final b = tx.outputs.first.scriptPubKey.toBytes();
+      return b.length == 34 && b[0] == 88 && b[1] == 32;
+    };
+    final isHogEx = isHogExTx(bundle.originalTransaction) && isHogExTx(bundle.ins.first);
+
     final fee = inputAmount - totalOutAmount;
     return ElectrumTransactionInfo(type,
         id: bundle.originalTransaction.txId(),
@@ -186,6 +197,7 @@ class ElectrumTransactionInfo extends TransactionInfo {
         direction: direction,
         amount: amount,
         date: date,
+        isHogEx: isHogEx,
         confirmations: bundle.confirmations);
   }
 

cw_bitcoin/lib/electrum_wallet.dart

@@ -1740,6 +1740,7 @@ abstract class ElectrumWalletBase
         final tx = await fetchTransactionInfo(hash: coin.hash);
         coin.isChange = address.isHidden;
         coin.confirmations = tx?.confirmations;
+        coin.isPegOut = tx?.isHogEx;
 
         updatedUnspentCoins.add(coin);
       } catch (_) {}

cw_bitcoin/lib/litecoin_wallet.dart

@@ -1214,21 +1214,14 @@ abstract class LitecoinWalletBase extends ElectrumWallet with Store {
         } else {
           // check if any of the inputs of this transaction are hog-ex:
           // this list is only non-mweb inputs:
-          bool isHogEx = true;
-
           final coin = unspentCoins
               .firstWhere((coin) => coin.hash == utxo.utxo.txHash && coin.vout == utxo.utxo.vout);
-
-          // TODO: detect actual hog-ex inputs
-
-          if (!isHogEx) {
-            continue;
-          }
+          if (coin.isPegOut != true) continue;
 
           int confirmations = coin.confirmations ?? 0;
           if (confirmations < 6) {
             throw Exception(
-                "A transaction input has less than 6 confirmations, please try again later.");
+                "A transaction input is an MWEB peg-out and has less than 6 confirmations, please try again later.");
           }
         }
       }