from subprocess import run, PIPE
from typing import Optional

from pynput import mouse

from . import qtile_func

class Backlight:
    def __init__(self, ctrl: Optional[str]=None) -> None:
        self.command = ['xbacklight']
        if ctrl:
            self.command += ['-ctrl', ctrl]

    def _get_brightness(self) -> int:
        return int(run(self.command + ['-get'], stdout=PIPE).stdout)

    def _set_brightness(self, percentage: int) -> None:
        run(self.command + [f'-set', str(percentage)])

    @qtile_func
    def change_backlight(self, action: str) -> None:
        """
        Increase or decrease bightness.
        Takes 'dec' or 'inc' as parameter. Goes 1% percent at a time from
        1% to 40% and 10% at a time from 40% to 100%.
        """
        brightness = self._get_brightness()
        if brightness != 1 or action != 'dec':
            if (brightness > 49 and action == 'dec') \
                    or (brightness > 39 and action == 'inc'):
                run(self.command + [f'-{action}', '10', '-fps', '10'])
            else:
                run(self.command + [f'-{action}', '1'])

    @qtile_func
    def turn_off_screen(self, screen_offset: int) -> None:
        """
        Turn off the laptop's screen.
        Use xset if there is only one screen, else, set backlight to
        zero. In both case, moving the mouse will turn on the screen.
        """
        current_brightness = self._get_brightness()
        self._set_brightness(0)

        def on_move(x: int, y: int):
            if x > screen_offset:
                self._set_brightness(current_brightness)
                raise mouse.Listener.StopException

        mouse.Listener(on_move=on_move).start()