#!/usr/bin/env python3

import sys, os

# config:
# put your device here
device="/sys/class/backlight/amdgpu_bl0/"

def smart_int(num):
    if (num[0] == '+'): return int(num[1:])
    return int(num)

def do_action(action):
    if (action == 'show'):
        curr = get_current()
        _max = get_max()
        print('screen brightness is at %s (%d/%d)' % (str(int(curr / _max * 100)), curr, _max));
        return
    if (action[-1:] == '%'):
        if (action[0] == "+" or action[0] == '-'):
            curr = get_current()
            max = get_max()
            curr_pc = curr / max * 100
            put_brightness(int(max * ((curr_pc + smart_int(action[:-1])) / 100)))
        else:
            put_brightness(int(get_max() * (int(action[:-1]) / 100)))

    elif (action[0] == '+' or action[0] == "-"):
        put_brightness(get_current() + smart_int(action))
    elif (action.isdigit()):
        put_brightness(int(action))

def get_current():
    with open(device + 'brightness', 'r') as f:
        return int(f.read().replace('\n', ''))

def put_brightness(ammount):
    ammount = num_in_range(ammount)
    print("screen brightnes is " + str(ammount));
    with open(device + 'brightness', 'r+') as f:
        f.write(str(ammount))

def get_max():
    with open(device + 'max_brightness', 'r') as f:
        return int(f.read().replace('\n', ''))

def num_in_range(num):
    max = get_max()
    if (num > max): num = max
    if (num < 0): num = 0
    return num


for action in sys.argv[1::]: do_action(action)