#include <stdlib.h>
#include <glib.h>
#include <gdk-pixbuf/gdk-pixbuf.h>

#include "util.h"

static void
find_image_in_wimmel(GdkPixbuf *wimmel, GdkPixbuf *match, GdkPixbuf *output)
{
	int wimmel_width, wimmel_height;
	int width, height;
	int i, j, k, n;
	int difference, barrier;

	wimmel_width = gdk_pixbuf_get_width(wimmel);
	wimmel_height = gdk_pixbuf_get_height(wimmel);
	width = gdk_pixbuf_get_width(match);
	height = gdk_pixbuf_get_height(match);

	barrier = width * height / 2;

	for (j = 0; j < wimmel_height - height; ++j) {
		for (i = 0; i < wimmel_width - width; ++i) {

			difference = 0;
			for (n = 0; n < height; ++n) {
				for (k = 0; k < width; ++k) {
					color_t color = get_pixel(wimmel, POINT(i + k, j + n));
					color_t color_orig = get_pixel(match, POINT(k, n));

#if 1
					if (abs(color.r - color_orig.r) > 50 ||
					    abs(color.g - color_orig.g) > 50 ||
					    abs(color.b - color_orig.b) > 50) {
						difference++;
						if (difference > barrier)
							break;
					}
#else
					difference += 
						abs(color.r - color_orig.r) + 
						abs(color.g - color_orig.g) +
						abs(color.b - color_orig.b);
						if (difference > barrier * 300)
							break;
#endif
				}
			}

#if 0
			if (difference < barrier * 300) {
#else
			if (difference < barrier) {
#endif
				g_print("kleeblatt @ %d, %d; difference: %d\n", i, j, difference);
				color_t color = COLOR(255, 0, 0, 0);
				for (k = i; k < i+width; k++) {
					put_pixel(output, POINT(k, j), color);
					put_pixel(output, POINT(k, j+height), color);
				}
				for (n = j; n < j+height; n++) {
					put_pixel(output, POINT(i, n), color);
					put_pixel(output, POINT(i+width, n), color);
				}
			}
		}
	}
}
struct find_params {
	GdkPixbuf *wimmel;
	GdkPixbuf *match;
	GdkPixbuf *output;
};

static gpointer
find_thread(gpointer data)
{
	struct find_params *params = data;

	find_image_in_wimmel(params->wimmel, params->match, params->output);
	g_object_unref(params->wimmel);
	g_object_unref(params->match);
	g_object_unref(params->output);

	free(params);

	return NULL;
}

int
main(int argc, char *argv[])
{
	char *file;
	GdkPixbuf *wimmel, *output;
	GdkPixbuf *match_tmp, *match;
	int i, j;
	int x1, y1, mwidth, mheight, width, height;
#define N 4
#define K 4
	GThread *thread[N][K];

	g_type_init();

	if (argc < 5)
		exit(EXIT_FAILURE);
	
	file = argv[1];
	x1 = atoi(argv[2]);
	y1 = atoi(argv[3]);
	mwidth = atoi(argv[4]);
	mheight = atoi(argv[5]);

	wimmel = gdk_pixbuf_new_from_file(file, NULL);
	if (!wimmel)
		exit(EXIT_FAILURE);

	output = gdk_pixbuf_copy(wimmel);

	match_tmp = gdk_pixbuf_new_subpixbuf(wimmel, x1, y1, mwidth, mheight);
	match = gdk_pixbuf_copy(match_tmp);
	g_object_unref(match_tmp);

	width = gdk_pixbuf_get_width(wimmel);
	height = gdk_pixbuf_get_height(wimmel);

	int step_x = width / N, step_y = height / K;
	int x, y;
	for (i = 0, x = 0; i < N; ++i, x += step_x) {
		for (j = 0, y = 0; j < K; ++j, y += step_y) {
			struct find_params *params = malloc(sizeof (struct find_params));;
			if (!params)
				exit(EXIT_FAILURE);
			
			int w = step_x + mwidth;
			int h = step_y + mheight;

			if (x + w > width)
				w = width - x;
			if (y + h > height)
				h = height - y;

			params->wimmel = gdk_pixbuf_new_subpixbuf(wimmel, x, y, w, h);
			params->output = gdk_pixbuf_new_subpixbuf(output, x, y, w, h);
			params->match = g_object_ref(match);

			thread[i][j] = g_thread_create(find_thread, params, TRUE, NULL);
		}
	}

	for (i = 0; i < N; ++i)
		for (j = 0; j < K; ++j)
			g_thread_join(thread[i][j]);

	gdk_pixbuf_save(output, "output.png", "png", NULL, NULL);
	g_object_unref(wimmel);
	g_object_unref(output);
	g_object_unref(match);
}