#!/usr/bin/env python3

import serial
import sys
import time
import os
import configparser
import gpiod
config_dump = __import__("modem-config-dump")

SERIAL_DEV = '/dev/ttyACM0'
WWAN_DEV = '/sys/class/net/wwan0'
SIM_CONFIG = '/etc/sim.conf'
APN_CONFIG = '/etc/apn.conf'

def execute_and_check(ser, cmd):
    tries = 0
    MAX_TRY = 5
    ser.flushInput()
    ser.write(cmd)
    ser.write(b'\r')
    s = ser.read_until(b'OK')
    if b'OK' not in s:
        print("Failed cmd : " + str(cmd))
        print("Output: " + str(s))
        tries += 1
        if tries < MAX_TRY:
            time.sleep(1)
            execute_and_check(ser, cmd)
        else:
            sys.exit(-1)
        tries = 0

def switch_sim():
    line = gpiod.find_line('SIM_SW')
    line.request(consumer='ublox-config', type=gpiod.LINE_REQ_DIR_OUT)
    line.set_value(0)

def sim_present(ser):
    cmd = b'AT+CCID?'
    while True:
        try:
            ser.flushInput()
            ser.write(cmd)
            ser.write(b'\r')
            s = ser.read_until(b'OK')
            if b'ERROR' in s:
                return False
            elif b'OK' in s:
                return True
        except Exception as e:
            print("Exception : " + str(e))
        time.sleep(1)
                
    return s

def check_sim_presence(ser):
    if sim_present(ser):
        print("sim present")
        return False
    else:
        print("no sim, switching to esim")
        switch_sim()
        return True

def sim_config(ser):
    config = configparser.ConfigParser()
    config.read(SIM_CONFIG)
    sim = config.get('default', 'SIM')
    print(sim)
    if sim == 'auto':
        return check_sim_presence(ser)
    elif sim == 'esim' or sim == 'ui-top':
        switch_sim()
        return True
    # ui-btm and main are default
    return False

def apn_setup(ser):
    if not os.path.exists(APN_CONFIG):
        print('No APN configured')
        return

    config = configparser.ConfigParser()
    config.read(APN_CONFIG)

    try:
        apn = config.get('default', 'apn')
    except:
        print('apn.conf malformed : no apn found\n')
        return
    try:
        user = '"' + config.get('default', 'user') + '"'
        try:
            password = '"' + config.get('default', 'password') + '"'
        except:
            print("No password for APN")
            password = 'NULL'
    except:
        print("No user for APN")
        user = 'NULL'
        password = 'NULL'

    if not apn:
        return
    auth = '1' if user is not 'NULL' else '0'
    print("Switching to airplane mode")
    execute_and_check(ser, b'AT+CFUN=4\r')

    print("Configuring default ctx")
    cmd = 'AT+UCGDFLT=0,"IP","' + str(apn) + '",0,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,0,' + auth + ',' + str(user) + ',' + str(password) + ',""\r'
    execute_and_check(ser, bytes(cmd, 'utf8'))

    print("Full functionality mode")
    execute_and_check(ser, b'AT+CFUN=1\r')

def poweroff(gpio):
    print('poweroff')
    if not os.path.exists(SERIAL_DEV):
        print('serial interface is not available')
        gpio.set_value(0)
        return -1
    ser = serial.Serial(SERIAL_DEV, 115200, timeout=0.5)
    ser.write(b'AT+CPWROFF\r')
    ser.close()

    time.sleep(2)

    gpio.set_value(0)

def main():
    line = gpiod.find_line('GSM_SUP_EN')
    line.request(consumer='ublox-config', type=gpiod.LINE_REQ_DIR_OUT)

    if len(sys.argv) == 2 and sys.argv[1] == 'stop':
        return poweroff(line)

    # Power on
    line.set_value(1)

    # Wait on device
    while not os.path.exists(SERIAL_DEV):
        time.sleep(1)
    ser = serial.Serial(SERIAL_DEV, 115200, timeout=0.5)

    rst = False
    if not os.path.exists(WWAN_DEV):
        print("Setting up bridge mode")
        execute_and_check(ser, b'AT+UBMCONF=2')

        print("Setting up USB mode to ECM")
        execute_and_check(ser, b'AT+UUSBCONF=2,"ECM",0')
        rst = True
    rst = sim_config(ser) or rst
    if rst:
        print("Resetting modem")
        ser.write(b'AT+CFUN=16\r')

        ser.close()
        while os.path.exists(SERIAL_DEV):
            time.sleep(1)
        while not os.path.exists(SERIAL_DEV):
            time.sleep(1)
        ser = serial.Serial(SERIAL_DEV, 115200, timeout=0.5)

    apn_setup(ser)
    config_dump.dump_modem_config(ser)
    ser.close()

if __name__ == '__main__':
    main()