#!/usr/bin/python

import serial
import sys
import re
import time
from os import listdir
from os.path import isfile, join
from os import system

DEBUG = False
VERBOSE = True

ret = system("rm -f /dev/ttyPIU /dev/ttyGPRS /dev/ttyDIU /dev/ttyGPS")

DEVDIR = "/dev"

###################

# sniff for our GPS
#
ttyfn = [f for f in listdir(DEVDIR) if re.match(r'^ttyACM', f)]
for devfn in ttyfn:
  if DEBUG: print devfn
  ser = serial.Serial(join(DEVDIR,devfn), 9600, bytesize=8, parity='N', stopbits=1, timeout=1, xonxoff=0, rtscts=0)


  x0 = ser.readline()
  if DEBUG: print "at n (0):", x0
  x1 = ser.readline()
  if DEBUG: print "at n (1):", x1
  x2 = ser.readline()
  if DEBUG: print "at n (2):", x2
  time.sleep(1)

  if (re.match(r'^\$GP', x0) or
      re.match(r'^\$GP', x1) or
      re.match(r'^\$GP', x2)):
    src_tty = join(DEVDIR,devfn)
    dst_tty = join(DEVDIR,"ttyGPS")

    if VERBOSE:
      print src_tty, "->", dst_tty

    system("ln -s " + src_tty + " " + dst_tty)

  ser.close()


###################

ttyfn = [f for f in listdir(DEVDIR) if re.match(r'^ttyUSB', f)]

# sniff for GPRS and PIU
#
for devfn in ttyfn:
  if DEBUG: print devfn
  ser = serial.Serial(join(DEVDIR,devfn), 115200, bytesize=8, parity='N', stopbits=1, timeout=1, xonxoff=0, rtscts=0)

  ser.write("\rAT\r")
  ser.flush()
  x0 = ser.readline()
  if DEBUG: print "at n (0):", x0
  x1 = ser.readline()
  if DEBUG: print "at n (1):", x1
  x2 = ser.readline()
  if DEBUG: print "at n (2):", x2
  time.sleep(1)

  x0 = x0.strip()
  x1 = x1.strip()
  x2 = x2.strip()

  if (x0 == "ok" or x0 == "OK" or
      x1 == "ok" or x1 == "OK" or
      x2 == "ok" or x2 == "OK"):
    src_tty = join(DEVDIR,devfn)
    dst_tty = join(DEVDIR,"ttyGPRS")

    if VERBOSE:
      print src_tty, "->", dst_tty

    system("ln -s " + src_tty + " " + dst_tty)

  if (x0[0:4] == "/?: " or
      x1[0:4] == "/?: " or
      x2[0:4] == "/?: "):
    src_tty = join(DEVDIR,devfn)
    dst_tty = join(DEVDIR,"ttyPIU")

    if VERBOSE:
      print src_tty, "->", dst_tty

    system("ln -s " + src_tty + " " + dst_tty)

  ser.close()