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

#include <xcb/xcb.h>
#include <xcb/xcb_icccm.h>
#include <xcb/xcb_util.h>

xcb_connection_t * c;
xcb_screen_t * s;
xcb_window_t w;

const uint32_t mask = XCB_CW_OVERRIDE_REDIRECT | XCB_CW_EVENT_MASK;
const uint32_t values[] = {1, XCB_EVENT_MASK_PROPERTY_CHANGE};

xcb_atom_t get_atom(xcb_connection_t *, const char *);

int main(int argc, char ** argv)
{
	(void) argc;
	(void) argv;
	c = xcb_connect(NULL, NULL);
	s = xcb_setup_roots_iterator(xcb_get_setup(c)).data;
	w = xcb_generate_id(c);
	xcb_atom_t TARGET_PROPERTY = get_atom(c, "_TARGET_SELECTION");
	xcb_atom_t UTF8_STRING = get_atom(c, "UTF8_STRING");  // TODO: Actually, focus on "rawest" format at first.
	xcb_create_window(
		c, XCB_COPY_FROM_PARENT, w, s->root, 0, 0, 1, 1, 0, XCB_COPY_FROM_PARENT, s->root_visual, mask, values);
	// TODO-maybe: Look for the selection owner first?
	xcb_convert_selection(c, w, XCB_ATOM_PRIMARY, UTF8_STRING, TARGET_PROPERTY, XCB_CURRENT_TIME);
	xcb_flush(c);
	xcb_generic_event_t * e;
	int done = 0;  // TODO: Look into continuous notifications?
	while (!done)
	{
		e = xcb_wait_for_event(c);
		if (NULL == e) break;
		if (XCB_SELECTION_NOTIFY != XCB_EVENT_RESPONSE_TYPE(e))
		{
			free(e);
			continue;
		}
		xcb_selection_notify_event_t * n = (xcb_selection_notify_event_t *) e;
		if (XCB_ATOM_PRIMARY == n->selection && XCB_NONE != n->property)
		{
			xcb_icccm_get_text_property_reply_t prop;
			xcb_get_property_cookie_t cookie = xcb_icccm_get_text_property(c, n->requestor, n->property);
			if (xcb_icccm_get_text_property_reply(c, cookie, &prop, NULL))
			{
				printf("%.*s\n", prop.name_len, prop.name);
				xcb_icccm_get_text_property_reply_wipe(&prop);
				xcb_delete_property(c, n->requestor, n->property);
				done = 1;
			}
		}
		free(e);
	}
	xcb_disconnect(c);
}

xcb_atom_t get_atom(xcb_connection_t * c, const char * name)
{
	xcb_intern_atom_cookie_t cookie = xcb_intern_atom(c, 0, strlen(name), name);
	xcb_intern_atom_reply_t * reply = xcb_intern_atom_reply(c, cookie, NULL);
	xcb_atom_t atom = reply->atom;
	free(reply);
	return atom;
}