#!/usr/bin/env python
#
# Copyright 2007 John Wiseman <jjwiseman@yahoo.com>
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

"""
A port of Tod E. Kurt's arduino-serial.c.
<http://todbot.com/blog/2006/12/06/arduino-serial-c-code-to-talk-to-arduino/>
"""

import termios
import fcntl
import os
import sys
import time
import getopt


# Map from the numbers to the termios constants (which are pretty much
# the same numbers).

BPS_SYMS = {
  4800:   termios.B4800,
  9600:   termios.B9600,
  19200:  termios.B19200,
  38400:  termios.B38400,
  57600:  termios.B57600,
  115200: termios.B115200
  }


# Indices into the termios tuple.

IFLAG = 0
OFLAG = 1
CFLAG = 2
LFLAG = 3
ISPEED = 4
OSPEED = 5
CC = 6


def bps_to_termios_sym(bps):
  return BPS_SYMS[bps]

  
class SerialPort:

  def __init__(self, serialport, bps):
    """Takes the string name of the serial port
    (e.g. "/dev/tty.usbserial","COM1") and a baud rate (bps) and
    connects to that port at that speed and 8N1. Opens the port in
    fully raw mode so you can send binary data.
    """
    self.fd = os.open(serialport, os.O_RDWR | os.O_NOCTTY | os.O_NDELAY)
    attrs = termios.tcgetattr(self.fd)
    bps_sym = bps_to_termios_sym(bps)
    # Set I/O speed.
    attrs[ISPEED] = bps_sym
    attrs[OSPEED] = bps_sym

    # 8N1
    attrs[CFLAG] &= ~termios.PARENB
    attrs[CFLAG] &= ~termios.CSTOPB
    attrs[CFLAG] &= ~termios.CSIZE
    attrs[CFLAG] |= termios.CS8
    # No flow control
    attrs[CFLAG] &= ~termios.CRTSCTS

    # Turn on READ & ignore contrll lines.
    attrs[CFLAG] |= termios.CREAD | termios.CLOCAL
    # Turn off software flow control.
    attrs[IFLAG] &= ~(termios.IXON | termios.IXOFF | termios.IXANY)

    # Make raw.
    attrs[LFLAG] &= ~(termios.ICANON | termios.ECHO | termios.ECHOE | termios.ISIG)
    attrs[OFLAG] &= ~termios.OPOST

    # See http://unixwiz.net/techtips/termios-vmin-vtime.html
    attrs[CC][termios.VMIN] = 0;
    attrs[CC][termios.VTIME] = 20;
    termios.tcsetattr(self.fd, termios.TCSANOW, attrs)

  def read_until(self, until):
    buf = ""
    done = False
    while not done:
      n = os.read(self.fd, 1)
      if n == '':
        time.sleep(0.01)
        continue
      buf = buf + n
      if n == until:
        done = True
    return buf

  def write(self, str):
    os.write(self.fd, str)

  def write_byte(self, byte):
    os.write(self.fd, chr(byte))


def main(args):
  port = None
  bps = 9600
  try:
    optlist, args = getopt.getopt(args[1:], 'hp:b:s:rn:d:',
                                  ['help', 'port=', 'baud=', 'send=', 'receive',
                                   'num=', 'delay='])
    for (o, v) in optlist:
      if o == '-d' or o == '--delay':
        n = float(v) / 1000.0
        time.sleep(n)
      elif o == '-h' or o =='--help':
        usage()
      elif o == '-b' or o =='--baud':
        bps = int(v)
      elif o == '-p' or o =='--port':
        port = SerialPort(v, bps)
      elif o =='-n' or o =='--num':
        n = int(v)
        port.write_byte(n)
      elif o == '-s' or o == '--send':
        port.write(v)
      elif o == '-r' or o == '--receive':
        print "Read %s" % (port.read_until('\n'),)
    sys.exit(0)
  except getopt.GetoptError, e:
    sys.stderr.write("%s: %s\n" % (args[0], e.msg))
    usage()
    sys.exit(1)
    

def usage():
  print """Usage: arduino-serial.py -p <serialport> [OPTIONS]
Options:
  -h, --help                   Print this help message
  -p, --port=serialport        Serial port Arduino is on
  -b, --baud=baudrate          Baudrate (bps) of Arduino
  -s, --send=data              Send data to Arduino
  -r, --receive                Receive data from Arduino & print it out
  -n  --num=num                Send a number as a single byte
  -d  --delay=millis           Delay for specified milliseconds

Note: Order is important. Set '-b' before doing '-p'.
      Used to make series of actions:  '-d 2000 -s hello -d 100 -r'
      means 'wait 2secs, send 'hello', wait 100msec, get reply'

"""


if __name__ == '__main__':
  main(sys.argv)