From a34605224aedce58118fbb6f7317b69afbe00ba3 Mon Sep 17 00:00:00 2001
From: Overtorment <overtorment@gmail.com>
Date: Tue, 21 Jun 2022 13:43:28 +0100
Subject: [PATCH] FIX: better support parsing taproot addresses from Electrum
 (rel #4749)

---
 blue_modules/BlueElectrum.d.ts         |  2 ++
 blue_modules/BlueElectrum.js           |  8 +++++++-
 class/index.js                         |  1 +
 class/wallets/taproot-wallet.js        | 23 +++++++++++++++++++++++
 tests/integration/BlueElectrum.test.js |  7 +++++++
 tests/unit/taproot-wallet.test.js      | 13 +++++++++++++
 6 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 class/wallets/taproot-wallet.js
 create mode 100644 tests/unit/taproot-wallet.test.js

diff --git a/blue_modules/BlueElectrum.d.ts b/blue_modules/BlueElectrum.d.ts
index 74ec97ca4..ad2c8ed10 100644
--- a/blue_modules/BlueElectrum.d.ts
+++ b/blue_modules/BlueElectrum.d.ts
@@ -85,3 +85,5 @@ export function estimateFees(): Promise<{ fast: number; medium: number; slow: nu
 export function broadcastV2(txhex: string): Promise<string>;
 
 export function getTransactionsFullByAddress(address: string): Promise<Transaction[]>;
+
+export function txhexToElectrumTransaction(txhes: string): Transaction;
diff --git a/blue_modules/BlueElectrum.js b/blue_modules/BlueElectrum.js
index 2754299f4..7717c0a3f 100644
--- a/blue_modules/BlueElectrum.js
+++ b/blue_modules/BlueElectrum.js
@@ -1,6 +1,6 @@
 import AsyncStorage from '@react-native-async-storage/async-storage';
 import { Alert } from 'react-native';
-import { LegacyWallet, SegwitBech32Wallet, SegwitP2SHWallet } from '../class';
+import { LegacyWallet, SegwitBech32Wallet, SegwitP2SHWallet, TaprootWallet } from '../class';
 import DefaultPreference from 'react-native-default-preference';
 import loc from '../loc';
 import WidgetCommunication from './WidgetCommunication';
@@ -1030,6 +1030,9 @@ function txhexToElectrumTransaction(txhex) {
     } else if (LegacyWallet.scriptPubKeyToAddress(out.script.toString('hex'))) {
       address = LegacyWallet.scriptPubKeyToAddress(out.script.toString('hex'));
       type = '???'; // TODO
+    } else {
+      address = TaprootWallet.scriptPubKeyToAddress(out.script.toString('hex'));
+      type = 'witness_v1_taproot';
     }
 
     ret.vout.push({
@@ -1047,3 +1050,6 @@ function txhexToElectrumTransaction(txhex) {
   }
   return ret;
 }
+
+// exported only to be used in unit tests
+module.exports.txhexToElectrumTransaction = txhexToElectrumTransaction;
diff --git a/class/index.js b/class/index.js
index faa5f6346..e22739dd7 100644
--- a/class/index.js
+++ b/class/index.js
@@ -2,6 +2,7 @@ export * from './app-storage';
 export * from './wallets/abstract-wallet';
 export * from './wallets/legacy-wallet';
 export * from './wallets/segwit-bech32-wallet';
+export * from './wallets/taproot-wallet';
 export * from './wallets/segwit-p2sh-wallet';
 export * from './wallets/hd-segwit-p2sh-wallet';
 export * from './wallets/hd-legacy-breadwallet-wallet';
diff --git a/class/wallets/taproot-wallet.js b/class/wallets/taproot-wallet.js
new file mode 100644
index 000000000..67e47d498
--- /dev/null
+++ b/class/wallets/taproot-wallet.js
@@ -0,0 +1,23 @@
+import { SegwitBech32Wallet } from './segwit-bech32-wallet';
+const bitcoin = require('bitcoinjs-lib');
+
+export class TaprootWallet extends SegwitBech32Wallet {
+  static type = 'taproot';
+  static typeReadable = 'P2 TR';
+  static segwitType = 'p2wpkh';
+
+  /**
+   * Converts script pub key to a Taproot address if it can. Returns FALSE if it cant.
+   *
+   * @param scriptPubKey
+   * @returns {boolean|string} Either bech32 address or false
+   */
+  static scriptPubKeyToAddress(scriptPubKey) {
+    try {
+      const publicKey = Buffer.from(scriptPubKey, 'hex');
+      return bitcoin.address.fromOutputScript(publicKey, bitcoin.networks.bitcoin);
+    } catch (_) {
+      return false;
+    }
+  }
+}
diff --git a/tests/integration/BlueElectrum.test.js b/tests/integration/BlueElectrum.test.js
index 83a77603b..d3788d9ff 100644
--- a/tests/integration/BlueElectrum.test.js
+++ b/tests/integration/BlueElectrum.test.js
@@ -168,6 +168,13 @@ describe('BlueElectrum', () => {
     }
   });
 
+  it('BlueElectrum can do txhexToElectrumTransaction()', () => {
+    const tx =
+      '0200000000010137d07edbc9db9a072a79c6f03e7274e52642d64d760143adc64832501087f37b00000000000000008002102700000000000022512040ef293a8a0ebaf8b351a27d89ff4b5b3822a635e4afdca77a30170c363bafa3e4ad0b00000000001600147dfe2249fa56a2f2b4b7ed3b16ee55e7c565198002483045022100e5b9f1c12e133ef659a0e5cc417b1f8625ba9e951bc7083408de2a33d6fb1a84022035ebb1e2d4ab620ee178dc6cd0b58c54123d1526d9a1b3efba612ea80e48edd101210295b56fc62cdd09c200ce19f873d5ddb3074f7141b2533448829385f48f093a1600000000';
+    const decoded = BlueElectrum.txhexToElectrumTransaction(tx);
+    assert.strictEqual(decoded.vout[0].scriptPubKey.addresses[0], 'bc1pgrhjjw52p6a03v635f7cnl6ttvuz9f34ujhaefm6xqtscd3m473szkl92g');
+  });
+
   it.each([false, true])('BlueElectrum can do multiGetBalanceByAddress(), disableBatching=%p', async function (diableBatching) {
     if (diableBatching) BlueElectrum.setBatchingDisabled();
     const balances = await BlueElectrum.multiGetBalanceByAddress([
diff --git a/tests/unit/taproot-wallet.test.js b/tests/unit/taproot-wallet.test.js
new file mode 100644
index 000000000..ba9a58989
--- /dev/null
+++ b/tests/unit/taproot-wallet.test.js
@@ -0,0 +1,13 @@
+import { TaprootWallet } from '../../class';
+const assert = require('assert');
+
+describe('Taproot wallet', () => {
+  it('can convert scriptPubKey to address', () => {
+    let address = TaprootWallet.scriptPubKeyToAddress('512040ef293a8a0ebaf8b351a27d89ff4b5b3822a635e4afdca77a30170c363bafa3');
+    assert.strictEqual(address, 'bc1pgrhjjw52p6a03v635f7cnl6ttvuz9f34ujhaefm6xqtscd3m473szkl92g');
+    address = TaprootWallet.scriptPubKeyToAddress();
+    assert.strictEqual(address, false);
+    address = TaprootWallet.scriptPubKeyToAddress('trololo');
+    assert.strictEqual(address, false);
+  });
+});