#!/usr/bin/python -S
# Copyright 2012 Google Inc. All Rights Reserved.
#
"""An extremely basic stty implementation for people who don't have it."""

__author__ = 'apenwarr@google.com (Avery Pennarun)'

import os
import sys
import termios
import tty


def Usage():
  sys.stderr.write('usage: %s <raw|sane|[-]echo|selftest>\n'
                   '  sets the tty mode\n' % sys.argv[0])
  sys.exit(99)


def SetSane(tc):
  """Returns a variant of tc with changes made by 'stty sane'."""
  tc = list(tc)
  tc[0] &= ~(termios.IGNBRK |
             termios.INLCR |
             termios.IGNCR |
             termios.IXOFF |
             termios.IUCLC |
             termios.IXANY)
  tc[0] |=  (termios.BRKINT |
             termios.ICRNL |
             termios.IMAXBEL |
             termios.IXON)
  tc[1] &= ~(termios.NLDLY |
             termios.CRDLY |
             termios.TABDLY |
             termios.BSDLY |
             termios.VTDLY |
             termios.FFDLY |
             termios.OLCUC |
             termios.OCRNL |
             termios.ONOCR |
             termios.ONLRET |
             termios.OFILL |
             termios.OFDEL)
  tc[1] |=  (termios.NL0 |
             termios.CR0 |
             termios.TAB0 |
             termios.BS0 |
             termios.VT0 |
             termios.FF0 |
             termios.OPOST |
             termios.ONLCR)
  tc[2] &= ~(0)
  tc[2] |=  (termios.CREAD)
  tc[3] &= ~(termios.ECHONL |
             termios.NOFLSH |
             termios.XCASE |
             termios.TOSTOP |
             termios.ECHOPRT)
  tc[3] |=  (termios.ICANON |
             termios.ISIG |
             termios.ECHO |
             termios.ECHOE |
             termios.ECHOK |
             termios.ECHOCTL |
             termios.ECHOKE)
  return tc


def main():
  if len(sys.argv) != 2:
    Usage()

  if sys.argv[1] == 'raw':
    tty.setraw(1)
  elif sys.argv[1] == 'sane':
    tc = termios.tcgetattr(0)
    tc = SetSane(tc)
    termios.tcsetattr(0, termios.TCSADRAIN, tc)
  elif sys.argv[1] == 'echo':
    tc = termios.tcgetattr(0)
    tc[3] |= termios.ECHO
    termios.tcsetattr(0, termios.TCSADRAIN, tc)
  elif sys.argv[1] == '-echo':
    tc = termios.tcgetattr(0)
    tc[3] &= ~termios.ECHO
    termios.tcsetattr(0, termios.TCSADRAIN, tc)
  elif sys.argv[1] == 'selftest':
    os.system('stty sane')
    tc_orig = termios.tcgetattr(0)
    tty.setraw(0)
    tc_raw = termios.tcgetattr(0)
    tc_sane = SetSane(tc_raw)
    termios.tcsetattr(0, termios.TCSANOW, tc_orig)
    print 'orig: %r' % [oct(i) for i in tc_orig[:4]]
    print 'sane: %r' % [oct(i) for i in tc_sane[:4]]
    print 'raw:  %r' % [oct(i) for i in tc_raw[:4]]
    assert tc_orig != tc_raw
    assert tc_raw != tc_sane
    tc_orig[0] |= termios.IXON
    tc_orig[3] &= 0xfff
    tc_sane[3] &= 0xfff
    assert tc_orig[:4] == tc_sane[:4]
  else:
    Usage()

if __name__ == '__main__':
  main()