#!/usr/bin/env python

import select
import sys
import tty

FD_IN = sys.stdin.fileno()


def wait_for_input(prompt, timeout):
  """Print a prompt, then wait for input, with a timeout.

  The timeout is specified as a number of seconds, in floating point. If
  any input is provided, then it will return True. If the timeout occurs,
  then False will be returned.

  Pass None for the timeout, if a timeout is not required.
  """
  sys.stdout.write(prompt)
  sys.stdout.flush()

  # want to save/restore the terminal attributes
  attrs = tty.tcgetattr(FD_IN)
  try:
    # put the tty into cbreak mode, rather than waiting for EOL.
    # use TCSANOW to avoid flushing the input.
    tty.setcbreak(FD_IN, tty.TCSANOW)

    # wait for input for <timeout> seconds
    inputs, _unused, _unused = select.select([FD_IN], [], [], timeout)
  finally:
    # restore the attributes
    tty.tcsetattr(FD_IN, tty.TCSANOW, attrs)

  # something arrived on STDIN
  if inputs:
    # drain all input that was provided
    tty.tcflush(FD_IN, tty.TCIFLUSH)
    return True

  # no input
  return False

if __name__ == '__main__':
  print wait_for_input('Press any key: ', 3)