static Systray *systray = NULL;
static unsigned long systrayorientation = _NET_SYSTEM_TRAY_ORIENTATION_HORZ;
static int systraybaridx = -1;
static int systraybarrule = -1;
static int systrayxpos = 0;

int
width_systray(Monitor *m, BarWidthArg *a)
{
	unsigned int w = 0;
	Client *i;
	if (!systray)
		return 1;
	if (showsystray)
		for (i = systray->icons; i; w += i->w + systrayspacing, i = i->next);
	return w ? w + systrayspacing : 0;
}

int
draw_systray(Monitor *m, BarDrawArg *a)
{
	systrayxpos = a->x;
	updatesystray();
	return systrayxpos + a->w;
}

int
click_systray(Monitor *m, Arg *arg, BarClickArg *a)
{
	return -1;
}

void
removesystrayicon(Client *i)
{
	Client **ii;

	if (!showsystray || !i)
		return;
	for (ii = &systray->icons; *ii && *ii != i; ii = &(*ii)->next);
	if (ii)
		*ii = i->next;
	free(i);
}

void
resizerequest(XEvent *e)
{
	XResizeRequestEvent *ev = &e->xresizerequest;
	Client *i;

	if ((i = wintosystrayicon(ev->window))) {
		updatesystrayicongeom(i, ev->width, ev->height);
		updatesystray();
	}
}

void
updatesystray(void)
{
	if (!showsystray)
		return;
	XSetWindowAttributes wa;
	Client *i;
	Monitor *m;
	unsigned int w = 1, r, mi;
	const BarRule *br;

	if (!systray) {
		/* init systray */
		if (!(systray = (Systray *)calloc(1, sizeof(Systray))))
			die("fatal: could not malloc() %u bytes\n", sizeof(Systray));

		/* Work out which bar the systray is to be displayed on */
		for (r = 0; r < LENGTH(barrules); r++) {
			br = &barrules[r];
			if (br->drawfunc == &draw_systray) {
				systraybaridx = br->bar;
				systraybarrule = r;
				if (br->monitor == -1 || br->monitor == 'A')
					m = selmon;
				else
					for (m = mons, mi = 0; m && mi < br->monitor && m->next; m = m->next, mi++);
				systray->win = m->bars[systraybaridx]->win;
				systray->mon = m;

				break;
			}
		}
		if (systraybaridx == -1) {
			fprintf(stderr, "dwm: unable to obtain system tray, no draw_systray in bar rules.\n");
			free(systray);
			systray = NULL;
			return;
		}

		XChangeProperty(dpy, systray->win, netatom[NetSystemTrayOrientation], XA_CARDINAL, 32,
				PropModeReplace, (unsigned char *)&systrayorientation, 1);
		#if BAR_ALPHA_PATCH
		XChangeProperty(dpy, systray->win, netatom[NetSystemTrayVisual], XA_VISUALID, 32,
				PropModeReplace, (unsigned char *)&visual->visualid, 1);
		#endif // BAR_ALPHA_PATCH
		XChangeProperty(dpy, systray->win, netatom[NetWMWindowType], XA_ATOM, 32,
				PropModeReplace, (unsigned char *)&netatom[NetWMWindowTypeDock], 1);
		XMapRaised(dpy, systray->win);
		XSetSelectionOwner(dpy, netatom[NetSystemTray], systray->win, CurrentTime);
		if (XGetSelectionOwner(dpy, netatom[NetSystemTray]) == systray->win) {
			sendevent(root, xatom[Manager], StructureNotifyMask, CurrentTime, netatom[NetSystemTray], systray->win, 0, 0);
			XSync(dpy, False);
		} else {
			fprintf(stderr, "dwm: unable to obtain system tray.\n");
			free(systray);
			systray = NULL;
			return;
		}
	}

	for (w = 0, i = systray->icons; i; i = i->next) {
		/* make sure the background color stays the same */
		wa.background_pixel = scheme[SchemeNorm][ColBg].pixel;
		XChangeWindowAttributes(dpy, i->win, CWBackPixel, &wa);
		XMapRaised(dpy, i->win);
		w += systrayspacing;
		i->x = systrayxpos + w;
		XMoveResizeWindow(dpy, i->win, i->x, 0, i->w, i->h);
		w += i->w;
		if (i->mon != systray->mon)
		    i->mon = systray->mon;
	}
}

void
updatesystrayicongeom(Client *i, int w, int h)
{
	if (i) {
		i->h = bh;
		if (w == h)
			i->w = bh;
		else if (h == bh)
			i->w = w;
		else
			i->w = (int) ((float)bh * ((float)w / (float)h));
		applysizehints(i, &(i->x), &(i->y), &(i->w), &(i->h), False);
		/* force icons into the systray dimensions if they don't want to */
		if (i->h > bh) {
			if (i->w == i->h)
				i->w = bh;
			else
				i->w = (int) ((float)bh * ((float)i->w / (float)i->h));
			i->h = bh;
		}
		if (i->w > 2*bh)
			i->w = bh;
	}
}

void
updatesystrayiconstate(Client *i, XPropertyEvent *ev)
{
	long flags;
	int code = 0;

	if (!showsystray || !i || ev->atom != xatom[XembedInfo] ||
			!(flags = getatomprop(i, xatom[XembedInfo])))
		return;

	if (flags & XEMBED_MAPPED && !i->tags) {
		i->tags = 1;
		code = XEMBED_WINDOW_ACTIVATE;
		XMapRaised(dpy, i->win);
		setclientstate(i, NormalState);
	}
	else if (!(flags & XEMBED_MAPPED) && i->tags) {
		i->tags = 0;
		code = XEMBED_WINDOW_DEACTIVATE;
		XUnmapWindow(dpy, i->win);
		setclientstate(i, WithdrawnState);
	}
	else
		return;
	sendevent(i->win, xatom[Xembed], StructureNotifyMask, CurrentTime, code, 0,
			systray->win, XEMBED_EMBEDDED_VERSION);
}

Client *
wintosystrayicon(Window w)
{
	Client *i = NULL;

	if (!showsystray || !w)
		return i;
	for (i = systray->icons; i && i->win != w; i = i->next);
	return i;
}