#!/usr/bin/env -S python3 -W ignore::DeprecationWarning

"""Simple dimmer for xss-lock."""

# It assumes we are using a compositor.

import gi ; gi.require_version("Gtk", "3.0")
from gi.repository import Gtk, Gdk, GLib
import cairo
import argparse


def expose_draw(widget, event, options, current):
    def dim(once=False):
        cr = Gdk.cairo_create(window)
        cr.set_source_rgba(0, 0, 0, current[0])
        cr.set_operator(cairo.OPERATOR_SOURCE)
        cr.paint()
        if not once:
            current[0] += options.step
            delta = options.max_opacity - options.min_opacity
            delay = options.delay * options.step * 1000 / delta
            if current[0] <= options.max_opacity:
                GLib.timeout_add(delay, dim)

    window = widget.get_window()
    if not current:
        # First time we are called.
        current.append(options.min_opacity)
        dim()
    else:
        dim(once=True)


if __name__ == "__main__":
    # Parse arguments
    parser = argparse.ArgumentParser()
    parser.add_argument("--min-opacity", type=float, default=0.2)
    parser.add_argument("--max-opacity", type=float, default=1)
    parser.add_argument("--step", type=float, default=0.02)
    parser.add_argument("--delay", type=float, default=10)
    options = parser.parse_args()

    display = Gdk.Display.get_default()
    for i in range(display.get_n_monitors()):
        geom = display.get_monitor(i).get_geometry()
        once = []

        # Create window
        window = Gtk.Window()
        window.set_wmclass("dimmer", "Dimmer")
        window.set_app_paintable(True)
        window.set_skip_pager_hint(True)
        window.set_skip_taskbar_hint(True)
        window.set_resizable(False)
        window.set_decorated(False)
        window.set_accept_focus(False)
        window.set_type_hint(Gdk.WindowTypeHint.SPLASHSCREEN)
        window.set_default_size(geom.width, geom.height)
        window.set_visual(window.get_screen().get_rgba_visual())

        window.connect("draw", expose_draw, options, [])
        window.connect("delete-event", Gtk.main_quit)

        window.show_all()
        window.move(geom.x, geom.y)

    Gtk.main()