/*
 * Copyright © 2011 Benjamin Franzke
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting documentation, and
 * that the name of the copyright holders not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  The copyright holders make no representations
 * about the suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
#include <assert.h>

#include <unistd.h>
#include <sys/types.h>
#include <sys/mman.h>

#include <wayland-client.h>

struct display {
	struct wl_display *display;
	struct {
		struct wl_compositor *compositor;
		struct wl_shm *shm;
	} interface;
	uint32_t mask;
};

struct window {
	struct display *display;
	struct {
		int width, height;
	} geometry;
	struct {
		struct wl_buffer *buffer;
		struct wl_surface *surface;
		uint8_t *data;
		int length;
		int stride;
	} shm_surface;
};

static void
redraw(struct wl_surface *surface, void *data, uint32_t time)
{
	struct window *window = data;
	uint32_t *pixel;
	int x,y;
	int a;

	for (y = 0; y < window->geometry.height; ++y) {
		pixel = (uint32_t *) (window->shm_surface.data +
				y * window->shm_surface.stride);
		a = 255 - y;
		for (x = 0; x < window->geometry.width; ++x, ++pixel) {
			if (x < 85)
				*pixel = (a << 24) | ((x + 170) << 16);
			else if (x < 170)
				*pixel = (a << 24) | ((x + 85) << 8);
			else
				*pixel = (a << 24) | (x);
		}
	}

	wl_buffer_damage(window->shm_surface.buffer, 0, 0,
			 window->geometry.width, window->geometry.height);
	wl_surface_damage(window->shm_surface.surface, 0, 0,
			  window->geometry.width, window->geometry.height);

	/* wl_display_frame_callback(window->display->display, redraw, window); */
}


static void
create_surface(struct window *window)
{
	struct display *display = window->display;
	struct wl_visual *visual;
	int fd;
	char filename[] = "/tmp/wayland-shm-XXXXXX";

	window->shm_surface.surface =
		wl_compositor_create_surface(display->interface.compositor);

#if 0
	window->shm_surface.stride = window->geometry.width * 4;
#else
	window->shm_surface.stride = window->geometry.width * 4 + 4;
#endif
	window->shm_surface.length =
		window->shm_surface.stride * window->geometry.height;

	fd = mkstemp(filename);
	if (fd < 0) {
		fprintf(stderr, "open %s failed: %m\n", filename);
		exit(1);
	}

	if (ftruncate(fd, window->shm_surface.length) < 0) {
		fprintf(stderr, "ftruncate failed: %m");
		close(fd);
		exit(1);
	}

	window->shm_surface.data =
		mmap(NULL, window->shm_surface.length,
		     PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
	unlink(filename);

	if (window->shm_surface.data == MAP_FAILED) {
		fprintf(stderr, "mmap failed: %m\n");
		exit(1);
	}

	visual = wl_display_get_argb_visual(display->display);
	window->shm_surface.buffer =
		wl_shm_create_buffer(display->interface.shm, fd,
				     window->geometry.width,
				     window->geometry.height,
				     window->shm_surface.stride, visual);
	close(fd);

	redraw(window->shm_surface.surface, window, 0);

	wl_surface_attach(window->shm_surface.surface,
			  window->shm_surface.buffer, 0, 0);
	wl_surface_map_toplevel(window->shm_surface.surface);
}

static void
display_handle_global(struct wl_display *display, uint32_t id,
		      const char *interface, uint32_t version, void *data)
{
	struct display *d = data;

	if (strcmp(interface, "wl_compositor") == 0) {
		d->interface.compositor = wl_compositor_create(display, id, 1);
	} else if (strcmp(interface, "wl_shm") == 0) {
		d->interface.shm = wl_shm_create(display, id, 1);
	}
}

static int
event_mask_update(uint32_t mask, void *data)
{
	struct display *d = data;

	d->mask = mask;

	return 0;
}

int
main(int argc, char **argv)
{
	struct display display = { 0 };
	struct window  window  = { 0 };

	memset(&display, 0, sizeof display);
	memset(&window,  0, sizeof window);

	window.display = &display;
	window.geometry.width  = 256;
	window.geometry.height = 256;

	display.display = wl_display_connect(NULL);
	assert(display.display);

	wl_display_add_global_listener(display.display,
				    display_handle_global, &display);
	/* process connection events */
	wl_display_iterate(display.display, WL_DISPLAY_READABLE);

	create_surface(&window);

	wl_display_get_fd(display.display, event_mask_update, &display);
	while (true)
		wl_display_iterate(display.display, display.mask);
	
	return 0;
}