#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>

#include <xcb/xcb.h>
#include <xcb/xinput.h>

/************************************************************************************************************/
/* _ ********************************************************************************************************/
/************************************************************************************************************/

static void _loop  (void);
static void _init  (void);
static void _reset (void);
static void _event (xcb_ge_generic_event_t *x_ev);

/************************************************************************************************************/
/************************************************************************************************************/
/************************************************************************************************************/

static xcb_connection_t *_x_con = NULL;
static xcb_screen_t     *_x_scr = NULL;
static xcb_window_t      _x_win = 0;

/************************************************************************************************************/
/************************************************************************************************************/
/************************************************************************************************************/

int
main(int argc, char **argv)
{
	_init();
	_loop();
	_reset();
}

/************************************************************************************************************/
/* _ ********************************************************************************************************/
/************************************************************************************************************/

static void
_event(xcb_ge_generic_event_t *x_ev)
{
	xcb_input_touch_begin_event_t     *x_ev_b = (xcb_input_touch_begin_event_t*)x_ev;
	xcb_input_touch_ownership_event_t *x_ev_o = (xcb_input_touch_ownership_event_t*)x_ev;

	switch (x_ev->event_type) {
		
		case XCB_INPUT_TOUCH_BEGIN:
			if (x_ev_b->event == _x_win) {
				printf("begin - %lu\n", x_ev_b->detail);
			}
			break;

		case XCB_INPUT_TOUCH_END:
			if (x_ev_b->event == _x_win) {
				printf("end - %lu\n", x_ev_b->detail);
			}
			break;

		case XCB_INPUT_TOUCH_UPDATE:
			printf("update - %lu\n", x_ev_b->detail);
			break;

		case XCB_INPUT_TOUCH_OWNERSHIP:
			if (x_ev_b->event == _x_win) {
				printf("ownership - %lu\n", x_ev_o->touchid);
			}
			break;
	}
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -*/

static void
_init(void)
{
	/* xcb session */

	_x_con = xcb_connect(NULL, NULL);
	_x_scr =  xcb_setup_roots_iterator(xcb_get_setup(_x_con)).data;

	/* xcb window */

	uint32_t mask_vals[2]; 

	mask_vals[0] = _x_scr->white_pixel;
	mask_vals[1] = XCB_EVENT_MASK_EXPOSURE;

	_x_win = xcb_generate_id(_x_con);	                       
	xcb_create_window(
		_x_con,
		XCB_COPY_FROM_PARENT,
		_x_win,
		_x_scr->root,
		0, 0,
		400, 400,
		0,
		XCB_WINDOW_CLASS_INPUT_OUTPUT,
		_x_scr->root_visual,
		XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK,
		mask_vals);

	xcb_map_window(_x_con, _x_win);

	/* xinput extension */

	/* https://lwn.net/Articles/475886/ */
	/* https://github.com/freedesktop/xcb-proto/blob/master/src/xinput.xml */

	/* thanks you random citizens */

	/* https://searchcode.com/file/635605507/src/plugins/platforms/xcb/qxcbconnection_xi2.cpp/ */
	/* https://stackoverflow.com/questions/39641675/how-to-register-events-using-libxcb-xinput */

	struct {
    	xcb_input_event_mask_t head;
    	xcb_input_xi_event_mask_t mask;
	} mask;

	mask.head.deviceid = XCB_INPUT_DEVICE_ALL;
	mask.head.mask_len = 1;
	
	mask.mask = 
		XCB_INPUT_XI_EVENT_MASK_TOUCH_BEGIN  |
		XCB_INPUT_XI_EVENT_MASK_TOUCH_END    |
		XCB_INPUT_XI_EVENT_MASK_TOUCH_UPDATE |
		XCB_INPUT_XI_EVENT_MASK_TOUCH_OWNERSHIP;

	xcb_input_xi_select_events(_x_con, _x_win, 1, (xcb_input_event_mask_t*)(&mask));

	/* end */

	xcb_flush(_x_con);
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -*/

static void
_loop(void)
{
	xcb_generic_event_t *x_ev;
	while ((x_ev = xcb_wait_for_event(_x_con))) {	
		switch (x_ev->response_type & ~0x80) {
			
			case XCB_EXPOSE:
				break;

			case XCB_GE_GENERIC:
				_event((xcb_ge_generic_event_t*)x_ev);
				break;
		}
		free(x_ev);
		xcb_flush(_x_con);
	}
}

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -*/

static void
_reset(void)
{
	xcb_unmap_window(_x_con, _x_win);
	xcb_destroy_window(_x_con, _x_win);
	xcb_disconnect(_x_con);
}