import argparse
import os

import itsdangerous


def generate(secret_key, username, expiration):
    s = itsdangerous.TimedJSONWebSignatureSerializer(secret_key, expires_in=expiration)
    return s.dumps(username)


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument('username', metavar='USERNAME', help='user name')
    parser.add_argument('expiration', metavar='EXPIRATION', type=int,
                        help='expiration time in seconds')
    args = parser.parse_args()
    secret_key = os.getenv('SECRET_KEY')
    api_key = generate(secret_key, args.username, args.expiration)
    print(api_key.decode('utf-8'))


if __name__ == '__main__':
    main()