/*
 * Copyright 2015 Javier S. Pedro <dev.git@javispedro.com>
 *
 * This file is part of MDock.
 *
 * MDock is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * MDock is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with MDock.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <gdk/gdkx.h>
#include "thumbnailer.h"

#define THUMBNAIL_MAX_WIDTH 196
#define THUMBNAIL_MAX_HEIGHT 196

typedef struct _ThumbnailData
{
	GdkPixmap * pix;
	guint update_source;
	time_t timestamp;
} ThumbnailData;

G_DEFINE_QUARK(mdock-thumbnail-data, mdock_thumbnail_data)

static inline ThumbnailData * thumbnail_data_new()
{
	return g_slice_new0(ThumbnailData);
}

static void thumbnail_data_destroy(ThumbnailData *tdata)
{
	g_clear_object(&tdata->pix);
	if (tdata->update_source) g_source_remove(tdata->update_source);
	g_slice_free(ThumbnailData, tdata);
}

void thumbnailer_enable_for_window(WnckWindow *window)
{
	g_object_set_qdata_full(G_OBJECT(window),
	                        mdock_thumbnail_data_quark(),
	                        thumbnail_data_new(),
	                        (GDestroyNotify)thumbnail_data_destroy);
}

static gboolean thumbnailer_do_update(gpointer data)
{
	ThumbnailData *tdata = g_object_get_qdata(G_OBJECT(data), mdock_thumbnail_data_quark());
	g_return_val_if_fail(tdata, G_SOURCE_REMOVE);
	thumbnailer_update_thumbnail(WNCK_WINDOW(data));
	tdata->update_source = 0;
	return G_SOURCE_REMOVE;
}

void thumbnailer_schedule_update(WnckWindow *window)
{
	ThumbnailData *tdata = g_object_get_qdata(G_OBJECT(window), mdock_thumbnail_data_quark());
	g_return_if_fail(tdata);
	if (!tdata->update_source) {
		tdata->update_source = g_timeout_add(500, thumbnailer_do_update, window);
	}
}

void thumbnailer_update_thumbnail(WnckWindow *window)
{
	GdkDisplay *display = gdk_display_get_default();
	GdkScreen *screen = gdk_display_get_default_screen(display);
	ThumbnailData *tdata = g_object_get_qdata(G_OBJECT(window), mdock_thumbnail_data_quark());
	g_return_if_fail(tdata);

	g_return_if_fail(wnck_window_is_active(window));

	GdkWindow *root = gdk_get_default_root_window();

	gdouble scale = MAX(gdk_screen_get_resolution(screen), 96.0) / 96.0;
	const gint max_w = THUMBNAIL_MAX_WIDTH * scale,
	           max_h = THUMBNAIL_MAX_HEIGHT * scale;

	int screen_x, screen_y, win_x, win_y, win_w, win_h, thumb_w, thumb_h, cur_w, cur_h;
	gdk_window_get_origin(root, &screen_x, &screen_y);
	wnck_window_get_client_window_geometry(window, &win_x, &win_y, &win_w, &win_h);

	if (win_w > max_w || win_h > max_h) {
		if (win_h > win_w) {
			thumb_w  = (max_h * win_w) / win_h;
			thumb_h = max_h;
		} else {
			thumb_w  = max_w;
			thumb_h = (max_w * win_h) / win_w;
		}
	} else {
		thumb_w = win_w;
		thumb_h = win_h;
	}

	if (tdata->pix) {
		gdk_pixmap_get_size(tdata->pix, &cur_w, &cur_h);
	}
	if (!tdata->pix || cur_w != thumb_w || cur_h != thumb_h) {
		g_clear_object(&tdata->pix);
		g_debug("Recreating pixmap for %s (%dx%d)", wnck_window_get_name(window), thumb_w, thumb_h);
		tdata->pix = gdk_pixmap_new(root, thumb_w, thumb_h, -1);
	}

	g_return_if_fail(tdata->pix);

	g_debug("Updating thumbnail for %s (%dx%d)", wnck_window_get_name(window), thumb_w, thumb_h);

	double scale_w = thumb_w / (double)win_w, scale_h = thumb_h / (double)win_h;
	cairo_t *cr = gdk_cairo_create(GDK_DRAWABLE(tdata->pix));
	cairo_scale(cr, scale_w, scale_h);
	gdk_cairo_set_source_window(cr, root, -(win_x - screen_x), -(win_y - screen_y));
	cairo_pattern_set_filter(cairo_get_source (cr), CAIRO_FILTER_FAST);
	cairo_paint(cr);
	cairo_destroy(cr);

	time(&tdata->timestamp);
}

GdkPixmap * thumbnailer_get_thumbnail(WnckWindow *window)
{
	ThumbnailData *tdata = g_object_get_qdata(G_OBJECT(window), mdock_thumbnail_data_quark());
	g_return_val_if_fail(tdata, NULL);
	return tdata->pix;
}