#!/bin/python3

import subprocess as sp
import sys
g_step = 10


def set_volume(value):
    sp.check_output(["xbacklight", "-set", str(int(value))])


def get_volume():
    return round(float(sp.check_output(["xbacklight",
                                        "-get"]).decode().split()[0]))


def volume_down():
    vol = get_volume()
    if vol <= g_step + 1:
        set_volume(1)
    else:
        set_volume(vol - g_step)


def volume_up():
    vol = get_volume()
    print(vol)
    if vol <= 1:
        set_volume(g_step)
    else:
        set_volume(vol + g_step)


def main():
    if len(sys.argv) != 2:
        return
    if sys.argv[1] == "up":
        volume_up()
    if sys.argv[1] == "down":
        volume_down()


if __name__ == "__main__":
    main()