From b50985aec7e4df44147c8294f40d28deb6a01d93 Mon Sep 17 00:00:00 2001
From: sneurlax <sneurlax@gmail.com>
Date: Tue, 26 Mar 2024 16:05:16 -0500
Subject: [PATCH] detect p2tr outputs

---
 .../intermediate/bip39_hd_currency.dart       | 20 ++++++++++++++-----
 .../electrumx_interface.dart                  | 14 +++++++++++++
 2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/lib/wallets/crypto_currency/intermediate/bip39_hd_currency.dart b/lib/wallets/crypto_currency/intermediate/bip39_hd_currency.dart
index fa5d5c796..5e6cd60e5 100644
--- a/lib/wallets/crypto_currency/intermediate/bip39_hd_currency.dart
+++ b/lib/wallets/crypto_currency/intermediate/bip39_hd_currency.dart
@@ -80,12 +80,22 @@ abstract class Bip39HDCurrency extends Bip39Currency {
       } catch (err) {
         // Bech32 decode fail
       }
-      if (networkParams.bech32Hrp != decodeBech32!.hrp) {
-        throw ArgumentError('Invalid prefix or Network mismatch');
-      }
-      if (decodeBech32.version != 0) {
-        throw ArgumentError('Invalid address version');
+      if (decodeBech32?.hrp != null) {
+        // P2TR Bech32m addresses have null hrp.
+        if (networkParams.bech32Hrp != decodeBech32!.hrp) {
+          throw ArgumentError('Invalid prefix or Network mismatch');
+        }
+        if (decodeBech32.version != 0) {
+          throw ArgumentError('Invalid address version');
+        }
+      } else {
+        // P2TR.
+        if (address.startsWith('bc1p') || address.startsWith('tb1p')) {
+          // P2TR (Taproot).
+          return DerivePathType.bip86;
+        }
       }
+
       // P2WPKH
       return DerivePathType.bip84;
     }
diff --git a/lib/wallets/wallet/wallet_mixin_interfaces/electrumx_interface.dart b/lib/wallets/wallet/wallet_mixin_interfaces/electrumx_interface.dart
index aa738c6ec..78847397e 100644
--- a/lib/wallets/wallet/wallet_mixin_interfaces/electrumx_interface.dart
+++ b/lib/wallets/wallet/wallet_mixin_interfaces/electrumx_interface.dart
@@ -682,6 +682,20 @@ mixin ElectrumXInterface<T extends Bip39HDCurrency> on Bip39HDWallet<T> {
 
     // TODO: use coinlib
 
+    // Check if any txData.recipients are taproot/P2TR outputs.
+    bool hasTaprootOutput = false;
+    for (final recipient in txData.recipients!) {
+      if (cryptoCurrency.addressType(address: recipient.address) ==
+          DerivePathType.bip86) {
+        hasTaprootOutput = true;
+      }
+    }
+
+    if (hasTaprootOutput) {
+      // Use Coinlib to construct taproot transaction.
+      // TODO [prio=high]: Implement taproot transaction construction.
+    }
+
     final txb = bitcoindart.TransactionBuilder(
       network: bitcoindart.NetworkType(
         messagePrefix: cryptoCurrency.networkParams.messagePrefix,