#!/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 optparse
import os
import pprint
import sys
import termios
import tty


def Usage():
  sys.stderr.write('usage: %s [raw|sane|[no]echo|selftest|<baud>|status>\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


# lifted from /usr/include/asm-generic/termbits.h:
baud_map = {
    '1200': 0000011,
    '2400': 0000013,
    '4800': 0000014,
    '9600': 0000015,
    '19200': 0000016,
    '38400': 0000017,
    '57600': 0010001,
    '115200': 0010002,
}


def main():
  parser = optparse.OptionParser()
  parser.add_option("-F" , "--file", dest="DEVICE")
  (options, args) = parser.parse_args()

  if len(args) != 1:
    Usage()

  fd = 0
  if options.DEVICE:
    fd = os.open(options.DEVICE, os.O_RDWR)

  if args[0] == 'raw':
    tty.setraw(0)
  elif args[0] == 'sane':
    tc = termios.tcgetattr(fd)
    tc = SetSane(tc)
    termios.tcsetattr(fd, termios.TCSADRAIN, tc)
  elif args[0] == 'echo':
    tc = termios.tcgetattr(fd)
    tc[3] |= termios.ECHO
    termios.tcsetattr(fd, termios.TCSADRAIN, tc)
  elif args[0] == 'noecho':
    tc = termios.tcgetattr(fd)
    tc[3] &= ~termios.ECHO
    termios.tcsetattr(fd, termios.TCSADRAIN, tc)
  elif args[0] == 'selftest':
    os.system('stty sane')
    tc_orig = termios.tcgetattr(fd)
    tty.setraw(fd)
    tc_raw = termios.tcgetattr(fd)
    tc_sane = SetSane(tc_raw)
    termios.tcsetattr(fd, 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]
  elif baud_map.get(args[0]):
    tc = termios.tcgetattr(fd)
    tc[4] = tc[5] = baud_map[args[0]]
    termios.tcsetattr(fd, termios.TCSADRAIN, tc)
  elif args[0] == 'status':
    tc = termios.tcgetattr(fd)
    pprint.pprint(tc)
  else:
    Usage()

if __name__ == '__main__':
  main()