encode method

String encode({ required String nodeId, required NodeRole role, List<String>? groupIds, String? microMessage, })

Encode local node metadata into an endpoint name string.

nodeId — full UUID of this node (only the first 8 chars are encoded). role — this node's mesh role. groupIds — all groups this node is subscribed to (may be empty). microMessage — optional tiny payload to broadcast connectionlessly.

Returns a pipe-delimited string under kEndpointNameMaxBytes.

Throws EndpointNameTooLongException if the combined group names and micro-message exceed the byte limit.

Implementation

String encode({
  required String nodeId,
  required NodeRole role,
  List<String>? groupIds,
  String? microMessage,
}) {
  final prefix = nodeId.length >= 8 ? nodeId.substring(0, 8) : nodeId;

  // Build the groups field: comma-separated or '*'
  final groupsField = (groupIds != null && groupIds.isNotEmpty)
      ? groupIds.join(kGroupSeparator)
      : '*';

  final parts = [
    kEndpointMagic,
    kAirpassProtocolVersion.toString(),
    role.code,
    groupsField,
    prefix,
  ];

  // Append micro-message if provided
  if (microMessage != null && microMessage.isNotEmpty) {
    parts.add(microMessage);
  }

  final encoded = parts.join(kEndpointDelimiter);

  // Validate byte length (UTF-8, not UTF-16 code units)
  final byteLength = utf8.encode(encoded).length;
  if (byteLength > kEndpointNameMaxBytes) {
    throw EndpointNameTooLongException(
      actualLength: byteLength,
      maxLength: kEndpointNameMaxBytes,
      encoded: encoded,
    );
  }

  return encoded;
}