def main()

in otp.py [0:0]
63 lines of code
16 McCabe index (conditional complexity)

def main():
  cmd = os.path.basename(sys.argv[0])
  if cmd in ALGOS:
    # switch to USAGE:
    #   $ ALGO SEQUENCE SEED
    # omit the prompt, and use argv
    algo = cmd
    seq = int(sys.argv[1])
    seed = sys.argv[2].lower().encode()
    # ignore any other argv
  else:
    parser = argparse.ArgumentParser(description='Compute OTP strings.')
    parser.add_argument('--test', help='Run the test suite.', nargs=0,
                        action=RunTests)
    parser.add_argument('--qr', help='Print a URL for a QR code',
                        action='store_true')
    parser.add_argument('args', nargs=argparse.REMAINDER)
  
    # Note: this may exit, if tests are run.
    parsed = parser.parse_args()

    parts = parsed.args

    # We have two possible forms:
    #   $ CMD [ALGO] SEQUENCE SEED
    #   $ CMD totp SEED

    # If the [ALGO] SEQUENCE SEED is not on the cmdline, then ask.
    if len(parts) < 2:
      line = input('Challenge? ')
      parts = line.split()

    if len(parts) == 2:
      if parts[0] == ALGO_TOTP:
        # form: totp SEED
        algo = ALGO_TOTP
        seq = None  # unused
      else:
        # form: SEQUENCE SEED
        algo = None
        seq = int(parts[0])
      seed = parts[1].lower().encode()
    elif len(parts) >= 3:
      algo = parts[0]
      seq = int(parts[1])
      seed = parts[2].lower().encode()
      # ignore anything else on line (eg. "ext")
    else:
      print('ERROR: challenge must have: [ALGO] SEQUENCE SEED ...')
      sys.exit(1)

  # Load a dictionary mapping seeds to passwords.
  pwds = load_passwords()

  if seed not in pwds:
    print('Creating new password for:', seed.decode())
    if not algo:
      algo = DEFAULT_ALGO
      print('NOTE: using "%s" algorithm' % (algo,))
    pwd = add_password(seed, algo)
  else:
    old_algo = algo
    pwd, algo = pwds[seed]
    if old_algo and algo != old_algo:
      print('NOTE: switched to "%s" algorithm' % (algo,))

  processor = ALGOS.get(algo)
  assert processor, 'Unknown/unsupported algorithm: "%s"' % (algo,)

  if algo == ALGO_TOTP:
    if parsed.qr:
      response = TOTP_QR_GEN % (pwd.decode(),)
    else:
      response = processor(pwd)
  else:
    value = processor(seed + pwd, seq)
    response = ' '.join(to_words(value))
  print('Response:', response)

  osname = platform.system()

  # Attempt to push this to the clipboard
  if osname == 'Darwin':
    result = subprocess.run(['pbcopy', '-pboard', 'general'], input=response.encode())
  else:
    result = subprocess.run(['xclip', '-selection', 'clipboard'], input=response.encode())
  if result.returncode == 0:
    print('NOTE: copied to clipboard')