#!/usr/bin/python

import serial
import time
import sys
import re

modem_device = "/dev/ttyACM1"
apn = "web.vodafone.de"

# TODO:  AT*EGNCI  (gsm-only)
#        AT*EWNCI  (umts-only)
#        AT+COPS   (operator select)
#
# *EGNCI: "26202","026E","00000000",6,50,24
#
# *EWNCI:
#   UARFCN,PSC,RSCP,ECNO,PathLoss
#   10588 ,287,36  ,14  ,158
#
# UARFCN = Channel, RSCP = RSSI, CID = PSC
# RNCid = CID_lang / 65536   (sometimes(?) == LAC)
# CID   = CID_lang % 65536
#

def send_command(modem, cmd, text):
    modem.write(cmd)
    if text != None:
	print text + ": ",
    response = modem.readlines()
    if text != None:
	print ('ERROR\r\n' in response and "Error" or "OK")
    return response


def get_pin_state(modem):
    modem.write('AT+CPIN?\r')
    response = modem.readlines()
    if "+CPIN: SIM PIN\r\n" in response:
	return False
    elif "+CPIN: READY\r\n" in response:
	return True
    else:
	print "[get_pin_state] Unknown response",
	print response
	return False


# determine whether there is a gsm or umts connection
# -1: unknown
#  0: gsm
#  2: umts
def connection_mode(modem):
    response = send_command(modem, 'AT+COPS?\r', None)
    for line in response:
	if line.startswith('+COPS: '):
	    values = line[7:].strip().split(',')
	    if len(values) == 1:
		return -1
	    else:
		return int(values[-1])
    return -1


def cell_info(modem):
    cells = set()

    # get GSM cell information
    send_command(modem, 'AT+CFUN=5\r', None)
    while connection_mode(modem) != 0:
	time.sleep(1)

    # get connected station
    modem.write('AT+CREG=2\r')
    modem.readlines()
    modem.write('AT+CREG?\r')
    response = modem.readlines()
    modem.write('AT+CREG=0\r')
    modem.readlines()
    for line in response:
	if line.startswith('+CREG: '):
	    results = line.rstrip()[7:].split(',')
	    if len(results) == 4:
		lac = int(results[2].strip('"'), 16)
		cid = int(results[3].strip('"'), 16)
	    break

    modem.write('AT*EHNET=2\r')
    response = modem.readlines()
    for line in response:
	if line.startswith('*EHNET: '):
	    mcc = int(line[8:].rstrip().strip('"')[:3])
	    mnc = int(line[8:].rstrip().strip('"')[3:])
    cells.add((mcc, mnc, lac, cid))


    # check stations until all are known (i.e. no '???' in response)
    retry = True
    while retry:
	retry = False
	response = send_command(modem, 'AT*EGNCI\r', None)
	if 'ERROR\r\n' in response:
	    print "error"
	    retry = True
	    time.sleep(1)
	    continue

	for line in response:
	    if line.startswith('*EGNCI: '):
		values = line[8:].rstrip().split(',')
		try:
		    mcc = int(values[0].strip('"')[:3])
		    mnc = int(values[0].strip('"')[3:])
		    lac = int(values[1].strip('"'), 16)
		    cid = int(values[2].strip('"'), 16)
		    if cid == 0:
			continue
		    cells.add((mcc, mnc, lac, cid))
		except:
		    retry = True
		    print "retrying"
		    time.sleep(2)
		    break
    
    for (mcc, mnc, lac, cid) in cells:
	print "MCC: " + str(mcc) + ",  MNC: " + str(mnc) + ",  LAC: " + str(lac) + ",  CellID: " + str(cid)


#    # get UMTS cell information
#    send_command(modem, 'AT+CFUN=6\r', None)
#    time.sleep(10)
#    response = send_command(modem, 'AT*EWNCI\r', None)
#    for line in response:
#	if line.startswith('*EWNCI: '):
#	    print line.rstrip()

#    # switch back to default mode
#    send_command(modem, 'AT+CFUN=1\r', None)


def print_state(modem):
    modem.timeout = 0.1
    modem.write('AT+CSQ\r')
    response = modem.readlines()
    for line in response:
	if line.startswith('+CSQ: '):
	    signal = line.rstrip()[6:].split(',')[0]
	    print "Signal: " + signal + "/31"
	    break

    mcc, mnc, lac, cid = -1, -1, -1, -1
    modem.write('AT*EHNET=2\r')
    response = modem.readlines()
    for line in response:
	if line.startswith('*EHNET: '):
	    mcc = line[8:].rstrip().strip('"')[:3]
	    mnc = line[8:].rstrip().strip('"')[3:]
	    break

    modem.write('AT+CREG=2\r')
    modem.readlines()
    modem.write('AT+CREG?\r')
    response = modem.readlines()
    modem.write('AT+CREG=0\r')
    modem.readlines()
    for line in response:
	if line.startswith('+CREG: '):
	    results = line.rstrip()[7:].split(',')
	    if len(results) == 4:
		lac = int(results[2].strip('"'), 16)
		cid = int(results[3].strip('"'), 16) % 65536  # last 2 bytes for umts
	    break
    print "MCC: " + str(mcc) + ",  MNC: " + str(mnc) + ",  LAC: " + str(lac) + ",  CellID: " + str(cid)



def start_modem(modem):
    if not get_pin_state(modem):
	pin = raw_input("Please enter PIN: ")
	send_command(modem, 'AT+CPIN="' + pin + '"\r', "Sending PIN")
    send_command(modem, 'AT+CFUN=1\r', "Starting modem")


def connect(modem):
    send_command(modem, 'AT+CGDCONT=1,"IP","' + apn + '"\r', "Setting up")
    send_command(modem, 'AT*ENAP=1,1\r', "Connecting")


def disconnect(modem):
    send_command(modem, 'AT*ENAP=0\r', "Disconnecting")


def stop_modem(modem):
    send_command(modem, 'AT+CFUN=4\r', "Stopping")


def show_usage():
    print "Usage: " + sys.argv[0] + " <command>"
    print "\tstart:        switch on modem and unlock sim"
    print "\tstop:         switch modem to powersave state"
    print "\tconnect:      connect to internet"
    print "\tdisconnect:   disconnect from internet"
    print "\tstate:        show signal/base station info"
    print "\tcellinfo:     show info about all received cells"

if len(sys.argv) != 2:
    show_usage()
    sys.exit(0)

modem = serial.Serial(modem_device, timeout=0.5)
modem.readlines()

if sys.argv[1] == "start":
    start_modem(modem)
elif sys.argv[1] == "stop":
    stop_modem(modem)
elif sys.argv[1] == "connect":
    start_modem(modem)
    connect(modem)
elif sys.argv[1] == "disconnect":
    disconnect(modem)
    stop_modem(modem)
elif sys.argv[1] == "state":
    print_state(modem)
elif sys.argv[1] == "cellinfo":
#    start_modem(modem)
    cell_info(modem)
else:
    show_usage()


modem.close()