/**
 * \file
 * [: description :]
 *
 * \author
 * Georg Hopp <georg@steffers.org>
 *
 * \copyright
 * Copyright © 2019 Georg Hopp
 *
 * This program 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.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>

#include <sys/ipc.h>
#include <sys/shm.h>

#include <xcb/xcb.h>
#include <xcb/shm.h>
#include <xcb/xcb_image.h>


#define WID 512
#define HEI 512


int main(){
	xcb_connection_t*       connection;
	xcb_window_t            window;
	xcb_screen_t*           screen;
	xcb_gcontext_t          gcontext;
	xcb_generic_event_t*    event;

	uint32_t value_mask;
	uint32_t value_list[2];

	//connect to the X server and get screen

	connection = xcb_connect(NULL, NULL);
	screen = xcb_setup_roots_iterator(xcb_get_setup(connection)).data;

	//create a window

	value_mask = XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK;
	value_list[0] = screen->black_pixel;
	value_list[1] = XCB_EVENT_MASK_EXPOSURE;

	window = xcb_generate_id(connection);

	xcb_create_window(
			connection,
			screen->root_depth,
			window,
			screen->root,
			0, 0,
			WID, HEI,
			0,
			XCB_WINDOW_CLASS_INPUT_OUTPUT,
			screen->root_visual,
			value_mask, value_list
			);

	//create a graphic context

	value_mask = XCB_GC_FOREGROUND | XCB_GC_GRAPHICS_EXPOSURES;
	value_list[0] = screen->black_pixel;
	value_list[1] = 0;

	gcontext = xcb_generate_id(connection);
	xcb_create_gc(connection, gcontext, window, value_mask, value_list);

	//map the window onto the screen

	xcb_map_window(connection, window);
	xcb_flush(connection);


	//Shm test
	xcb_shm_query_version_reply_t*  reply;
	xcb_shm_segment_info_t          info;

	reply = xcb_shm_query_version_reply(
			connection,
			xcb_shm_query_version(connection),
			NULL
			);

	if(!reply || !reply->shared_pixmaps){
		printf("Shm error...\n");
		exit(0);
	}

	info.shmid   = shmget(IPC_PRIVATE, WID*HEI*4, IPC_CREAT | 0777);
	info.shmaddr = shmat(info.shmid, 0, 0);

	info.shmseg = xcb_generate_id(connection);
	xcb_shm_attach(connection, info.shmseg, info.shmid, 0);
	shmctl(info.shmid, IPC_RMID, 0);

	uint32_t* data = (uint32_t*)info.shmaddr;

	xcb_pixmap_t pix = xcb_generate_id(connection);
	xcb_shm_create_pixmap(
			connection,
			pix,
			window,
			WID, HEI,
			screen->root_depth,
			info.shmseg,
			0
			);

	int i = 0;
	while(1){
		usleep(10000);

		data[i] = 0xFFFFFF;
		i++;

		xcb_copy_area(
				connection,
				pix,
				window,
				gcontext,
				0, 0, 0, 0,
				WID, HEI
				);

		xcb_flush(connection);
	}

	xcb_shm_detach(connection, info.shmseg);
	shmdt(info.shmaddr);

	xcb_free_pixmap(connection, pix);

	xcb_destroy_window(connection, window);
	xcb_disconnect(connection);

	return 0;
}

// vim: set ts=4 sw=4: