parseExtendedKey function

Implementation

ParsedExtendedKey parseExtendedKey(String value) {
  try {
    final payload = Base58Decoder.checkDecode(value);
    if (payload.length != 78) {
      throw const WalletHDDerivationException(
          'extended key payload must be 78 bytes');
    }
    final versionHex = BytesUtils.toHexString(payload.sublist(0, 4));
    final isPrivate = payload[45] == 0;
    final entry = _formats.entries
        .where((entry) =>
            versionHex ==
            (isPrivate ? entry.value.private : entry.value.public))
        .firstOrNull;
    if (entry == null) {
      throw WalletHDDerivationException(
          'unknown extended-key version: $versionHex');
    }
    final depth = payload[4];
    if (depth == 0 &&
        (payload.sublist(5, 9).any((byte) => byte != 0) ||
            payload.sublist(9, 13).any((byte) => byte != 0))) {
      throw const WalletHDDerivationException(
          'root extended key must have zero parent fingerprint and child number');
    }
    final node =
        Bip32Slip10Secp256k1.fromExtendedKey(value, _versions(entry.value));
    return ParsedExtendedKey._(
        value: value,
        versionHex: versionHex,
        format: entry.key,
        isPrivate: isPrivate,
        depth: node.depth.toInt(),
        childNumber: node.index.toInt(),
        parentFingerprintHex:
            BytesUtils.toHexString(node.parentFingerPrint.toBytes()),
        chainCodeHex: BytesUtils.toHexString(node.chainCode.toBytes()),
        publicKeyHex: BytesUtils.toHexString(node.publicKey.compressed),
        node: node);
  } catch (error) {
    if (error is WalletHDDerivationException) rethrow;
    throw const WalletHDDerivationException(
        'invalid extended key checksum or material');
  }
}