#!/usr/bin/env python

import os
import re
import subprocess

from gi.repository import GLib
from dbus import SessionBus
from dbus.mainloop.glib import DBusGMainLoop

previous_xrandr = 'xrandr --output DSI-1 --auto'


def get_current_xrandr() -> str:
    proc = subprocess.Popen(['unxrandr'], stdout=subprocess.PIPE)
    return proc.communicate()[0].decode().strip()


def is_display_on() -> bool:
    proc = subprocess.Popen(['xrandr', '-q'], stdout=subprocess.PIPE)
    out = proc.communicate()[0].decode().strip()
    lines = [
        line for line in out.split('\n')
        if line.startswith('DSI-1 ')
    ]

    assert lines, 'Display DSI-1 not found'
    m = re.search(r'^DSI-1\s+(connected\s+)?(primary\s+)?\d+x\d+\+\d+\+\d+', lines[0])
    return m is not None


def signal_handler(name, value):
    global previous_xrandr
    if name != 'button':
        return

    is_on = is_display_on()
    if is_on:
        previous_xrandr = get_current_xrandr()
        os.system('xrandr --output DSI-1 --off')
    else:
        os.system(previous_xrandr)


def main():
    xrandr = get_current_xrandr()

    loop = DBusGMainLoop()
    bus = SessionBus(mainloop=loop)
    bus.add_signal_receiver(
        signal_handler, 'updateEvent',
        'io.cutiepi.interface', path='/mcu'
    )

    loop = GLib.MainLoop()

    try:
        loop.run()
    finally:
        loop.quit()


if __name__ == '__main__':
    main()