stack_wallet/lib/utilities/bip47_utils.dart

/* 
 * This file is part of Stack Wallet.
 * 
 * Copyright (c) 2023 Cypher Stack
 * All Rights Reserved.
 * The code is distributed under GPLv3 license, see LICENSE file for details.
 * Generated by Cypher Stack on 2023-05-26
 *
 */

import 'dart:typed_data';

import 'package:bip47/src/util.dart';

import '../models/isar/models/blockchain_data/v2/output_v2.dart';
import '../models/isar/models/blockchain_data/v2/transaction_v2.dart';

abstract class Bip47Utils {
  /// looks at tx outputs and returns a blinded payment code if found
  static Uint8List? getBlindedPaymentCodeBytesFrom(TransactionV2 transaction) {
    for (int i = 0; i < transaction.outputs.length; i++) {
      final bytes = getBlindedPaymentCodeBytesFromOutput(
        transaction.outputs.elementAt(i),
      );
      if (bytes != null) {
        return bytes;
      }
    }

    return null;
  }

  static Uint8List? getBlindedPaymentCodeBytesFromOutput(OutputV2 output) {
    Uint8List? blindedCodeBytes;

    final List<String>? scriptChunks = output.scriptPubKeyAsm?.split(" ");
    if (scriptChunks?.length == 2 && scriptChunks?[0] == "OP_RETURN") {
      final blindedPaymentCode = scriptChunks![1];
      final bytes = blindedPaymentCode.fromHex;

      // https://en.bitcoin.it/wiki/BIP_0047#Sending
      if (bytes.length == 80 && bytes.first == 1) {
        blindedCodeBytes = bytes;
      }
    }

    return blindedCodeBytes;
  }
}