#!/usr/bin/python3

"""Saver module for xsecurelock.

It displays a background image, clock and weather. Configuration is
done through environment variables:

 - XSECURELOCK_SAVER_IMAGE: path to the background image to use
 - XSECURELOCK_SAVER_FONT: font family to use to display clock
 - XSECURELOCK_SAVER_FONT_SIZE: font size to use to display clock

"""

import os
import types
import datetime
import gi

gi.require_version("Gtk", "3.0")
from gi.repository import Gtk, Gdk, GdkX11, GLib, GdkPixbuf, Gio
import cairo


def on_win_realize(widget, ctx):
    """On realization, embed into XSCREENSAVER_WINDOW and remember parent position."""
    parent_wid = int(os.getenv("XSCREENSAVER_WINDOW", 0))
    if not parent_wid:
        return
    parent = GdkX11.X11Window.foreign_new_for_display(widget.get_display(), parent_wid)
    x, y, w, h = parent.get_geometry()
    ctx.position = x, y
    window = widget.get_window()
    window.resize(w, h)
    window.reparent(parent, 0, 0)


def on_win_draw(widget, cctx, ctx):
    """Draw background image."""
    cctx.set_operator(cairo.OPERATOR_SOURCE)
    if not ctx.background:
        cctx.set_source_rgba(0, 0, 0, 1)
        cctx.paint()
        return

    x, y = ctx.position
    wwidth, wheight = widget.get_size()
    scale = widget.get_scale_factor()
    bg = ctx.background.new_subpixbuf(
        x * scale, y * scale, wwidth * scale, wheight * scale
    )
    cctx.save()
    cctx.scale(1 / scale, 1 / scale)
    Gdk.cairo_set_source_pixbuf(cctx, bg, 0, 0)
    cctx.paint()
    cctx.restore()


def on_overlay_draw(widget, cctx, ctx):
    """Draw overlay."""
    # Clock
    cctx.set_operator(cairo.OPERATOR_SOURCE)
    wwidth, wheight = widget.get_parent().get_size()
    now = datetime.datetime.now().strftime("%H:%M")
    cctx.select_font_face(
        ctx.font_family, cairo.FONT_SLANT_NORMAL, cairo.FONT_WEIGHT_BOLD
    )
    cctx.set_font_size(ctx.font_size)
    _, _, twidth, theight, _, _ = cctx.text_extents("00:00")
    text_position = wwidth // 2 - twidth // 2, wheight // 3 - theight // 2
    cctx.move_to(*text_position)
    cctx.set_source_rgba(1, 1, 1, 0.8)
    cctx.show_text(now)
    cctx.move_to(*text_position)
    cctx.set_source_rgb(0, 0, 0)
    cctx.set_line_width(2)
    cctx.text_path(now)
    cctx.stroke()


def on_background_change(monitor, f1, f2, event, ctx):
    """Update background when changed."""
    if event not in (
        Gio.FileMonitorEvent.CHANGES_DONE_HINT,
        Gio.FileMonitorEvent.RENAMED,
    ):
        return
    try:
        new_background = GdkPixbuf.Pixbuf.new_from_file(ctx.background_image)
    except Exception:
        return
    ctx.background = new_background
    ctx.window.queue_draw()


def on_clock_change(ctx):
    ctx.overlay.queue_draw()
    now = datetime.datetime.now()
    GLib.timeout_add((60 - now.second) * 1000, on_clock_change, ctx)


if __name__ == "__main__":
    ctx = types.SimpleNamespace()
    ctx.background_image = os.getenv("XSECURELOCK_SAVER_IMAGE", None)
    ctx.font_size = int(os.getenv("XSECURELOCK_SAVER_FONT_SIZE", 120))
    ctx.font_family = os.getenv("XSECURELOCK_SAVER_FONT", "Iosevka Aile")
    ctx.background = None
    ctx.position = [0, 0]

    ctx.window = Gtk.Window()
    ctx.window.set_app_paintable(True)
    ctx.window.set_visual(ctx.window.get_screen().get_rgba_visual())
    ctx.window.connect("realize", on_win_realize, ctx)
    ctx.window.connect("draw", on_win_draw, ctx)
    ctx.window.connect("delete-event", Gtk.main_quit)

    ctx.overlay = Gtk.DrawingArea()
    ctx.overlay.connect("draw", on_overlay_draw, ctx)
    ctx.window.add(ctx.overlay)
    on_clock_change(ctx)

    if ctx.background_image:
        gfile = Gio.File.new_for_path(ctx.background_image)
        monitor = gfile.monitor_file(Gio.FileMonitorFlags.WATCH_MOVES, None)
        monitor.connect("changed", on_background_change, ctx)
        on_background_change(None, None, None, Gio.FileMonitorEvent.CHANGES_DONE_HINT, ctx)

    ctx.window.show_all()

    # Main loop
    Gtk.main()