/**
 * Validates a device token
 *
 * Will convert to string and removes invalid characters as required.
 */
function token(input) {
  let token;

  if (typeof input === 'string') {
    token = input;
  } else if (Buffer.isBuffer(input)) {
    token = input.toString('hex');
  }

  token = token.replace(/[^0-9a-f]/gi, '');

  if (token.length === 0) {
    throw new Error('Token has invalid length');
  }

  return token;
}

module.exports = token;