#include <X11/Xlib-xcb.h>
#include <xcb/res.h>

static xcb_connection_t *xcon;

void
swallow(Client *p, Client *c)
{
	if (c->noswallow || c->isterminal)
		return;

	detach(c);
	detachstack(c);

	setclientstate(c, WithdrawnState);
	XUnmapWindow(dpy, p->win);

	p->swallowing = c;
	c->mon = p->mon;

	Window w = p->win;
	p->win = c->win;
	c->win = w;
	updatetitle(p);
	arrange(p->mon);
	XMoveResizeWindow(dpy, p->win, p->x, p->y, p->w, p->h);
	configure(p);
	updateclientlist();
}

void
unswallow(Client *c)
{
	c->win = c->swallowing->win;

	free(c->swallowing);
	c->swallowing = NULL;

	updatetitle(c);
	arrange(c->mon);
	XMapWindow(dpy, c->win);
	XMoveResizeWindow(dpy, c->win, c->x, c->y, c->w, c->h);
	configure(c);
	setclientstate(c, NormalState);
}

pid_t
winpid(Window w)
{
	pid_t result = 0;

	xcb_res_client_id_spec_t spec = {0};
	spec.client = w;
	spec.mask = XCB_RES_CLIENT_ID_MASK_LOCAL_CLIENT_PID;

	xcb_generic_error_t *e = NULL;
	xcb_res_query_client_ids_cookie_t c = xcb_res_query_client_ids(xcon, 1, &spec);
	xcb_res_query_client_ids_reply_t *r = xcb_res_query_client_ids_reply(xcon, c, &e);

	if (!r)
		return (pid_t)0;

	xcb_res_client_id_value_iterator_t i = xcb_res_query_client_ids_ids_iterator(r);
	for (; i.rem; xcb_res_client_id_value_next(&i)) {
		spec = i.data->spec;
		if (spec.mask & XCB_RES_CLIENT_ID_MASK_LOCAL_CLIENT_PID) {
			uint32_t *t = xcb_res_client_id_value_value(i.data);
			result = *t;
			break;
		}
	}

	free(r);

	if (result == (pid_t)-1)
		result = 0;
	return result;
}

pid_t
getparentprocess(pid_t p)
{
	unsigned int v = 0;

#ifdef __linux__
	FILE *f;
	char buf[256];
	snprintf(buf, sizeof(buf) - 1, "/proc/%u/stat", (unsigned)p);

	if (!(f = fopen(buf, "r")))
		return 0;

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-result"
	fscanf(f, "%*u %*s %*c %u", &v);
#pragma GCC diagnostic pop
	fclose(f);
#endif /* __linux__ */

	return (pid_t)v;
}

int
isdescprocess(pid_t p, pid_t c)
{
	while (p != c && c != 0)
		c = getparentprocess(c);

	return (int)c;
}

Client *
termforwin(const Client *w)
{
	Client *c;
	Monitor *m;

	if (!w->pid || w->isterminal)
		return NULL;

	c = selmon->sel;
	if (c && c->isterminal && !c->swallowing && c->pid && isdescprocess(c->pid, w->pid))
		return c;

	for (m = mons; m; m = m->next) {
		for (c = m->clients; c; c = c->next) {
			if (c->isterminal && !c->swallowing && c->pid && isdescprocess(c->pid, w->pid))
				return c;
		}
	}

	return NULL;
}

Client *
swallowingclient(Window w)
{
	Client *c;
	Monitor *m;

	for (m = mons; m; m = m->next) {
		for (c = m->clients; c; c = c->next) {
			if (c->swallowing && c->swallowing->win == w)
				return c;
		}
	}

	return NULL;
}