encodeNprofile static method

String encodeNprofile({ required String pubkey, List<String>? relays, })

Encode nprofile (profile reference) pubkey - 32-byte hex public key (required) relays - optional list of relay URLs where the profile may be found

Implementation

static String encodeNprofile({
  required String pubkey,
  List<String>? relays,
}) {
  final tlvData = <int>[];

  // Type 0: pubkey (special) - 32 bytes
  final pubkeyBytes = hex.decode(pubkey);
  if (pubkeyBytes.length != 32) {
    throw ArgumentError('Public key must be 32 bytes (64 hex characters)');
  }
  tlvData.add(0); // type
  tlvData.add(32); // length
  tlvData.addAll(pubkeyBytes); // value

  // Type 1: relays (optional, can be multiple)
  if (relays != null) {
    for (final relay in relays) {
      final relayBytes = utf8.encode(relay);
      if (relayBytes.length > 255) {
        throw ArgumentError(
            'Relay URL too long: ${relay.length} bytes (max 255)');
      }
      tlvData.add(1); // type
      tlvData.add(relayBytes.length); // length
      tlvData.addAll(relayBytes); // value
    }
  }

  // Convert to bech32
  final data = Nip19Utils.convertBits(tlvData, 8, 5, true);
  var encoder = Bech32Encoder();
  Bech32 input = Bech32(Hrps.kNprofile, data);
  var encoded = encoder.convert(input, input.hrp.length + data.length + 10);
  return encoded;
}