func newAudio(Xu *xgbutil.XUtil) (*audio, error) {
	m, err := OpenMixer()
	if err != nil {
		return nil, err
	}
	defer func() {
		// set m to nil on final success
		if m != nil {
			_ = m.Close()
		}
	}()

	a := &audio{
		mixer: m,
	}

	for _, k := range []struct {
		key string
		fn  keybind.KeyPressFun
	}{
		{"XF86AudioRaiseVolume", a.up},
		{"XF86AudioLowerVolume", a.down},
		{"XF86AudioMute", a.mute},
	} {
		if err := k.fn.Connect(Xu, Xu.RootWin(), k.key, true); err != nil {
			return nil, err
		}
	}

	m = nil
	return a, nil
}

func newWindow(X *xgbutil.XUtil) {
	win, err := xwindow.Generate(X)
	if err != nil {
		log.Fatal(err)
	}
	win.Create(X.RootWin(), 0, 0, 200, 200,
		xproto.CwBackPixel|xproto.CwEventMask,
		0, xproto.EventMaskButtonRelease)
	win.WMGracefulClose(
		func(w *xwindow.Window) {
			xevent.Detach(w.X, w.Id)
			mousebind.Detach(w.X, w.Id)
			w.Destroy()
			xevent.Quit(X)
			Done <- true
		})

	win.Map()

	err = mousebind.ButtonReleaseFun(
		func(X *xgbutil.XUtil, ev xevent.ButtonReleaseEvent) {
			newWindow(X)
		}).Connect(X, win.Id, "1", false, false)

	if err != nil {
		log.Fatal(err)
	}
}

func query(X *xgbutil.XUtil) xinerama.Heads {
	if X.ExtInitialized("XINERAMA") {
		heads, err := xinerama.PhysicalHeads(X)
		if err != nil || len(heads) == 0 {
			if err == nil {
				logger.Warning.Printf("Could not find any physical heads " +
					"with the Xinerama extension.")
			} else {
				logger.Warning.Printf("Could not load physical heads via "+
					"Xinerama: %s", err)
			}
			logger.Warning.Printf("Assuming one head with size equivalent " +
				"to the root window.")
		} else {
			return heads
		}
	}

	// If we're here, then something went wrong or the Xinerama extension
	// isn't available. So query the root window for its geometry and use that.
	rgeom := xwindow.RootGeometry(X)
	return xinerama.Heads{
		xrect.New(rgeom.X(), rgeom.Y(), rgeom.Width(), rgeom.Height()),
	}
}

// New allocates and initializes a new DockApp.  NewDockApp does not initialize
// the window contents and does not map the window to the display screen.  The
// window is mapped to the screen when the Main method is called on the
// returned DockApp.
func New(x *xgbutil.XUtil, rect image.Rectangle) (*DockApp, error) {
	win, err := xwindow.Generate(x)
	if err != nil {
		log.Fatalf("generate window: %v", err)
	}
	win.Create(x.RootWin(), 0, 0, rect.Size().X, rect.Size().Y, 0)

	// Set WM hints so that Openbox puts the window into the dock.
	hints := &icccm.Hints{
		Flags:        icccm.HintState | icccm.HintIconWindow,
		InitialState: icccm.StateWithdrawn,
		IconWindow:   win.Id,
		WindowGroup:  win.Id,
	}
	err = icccm.WmHintsSet(x, win.Id, hints)
	if err != nil {
		win.Destroy()
		return nil, fmt.Errorf("wm hints: %v", err)
	}
	img := xgraphics.New(x, rect)
	err = img.XSurfaceSet(win.Id)
	if err != nil {
		img.Destroy()
		win.Destroy()
		return nil, fmt.Errorf("xsurface set: %v", err)
	}
	app := &DockApp{
		x:   x,
		img: img,
		win: win,
	}
	return app, nil
}

func newParent(X *xgbutil.XUtil, cid xproto.Window) (*Parent, error) {
	parent, err := xwindow.Generate(X)
	if err != nil {
		logger.Error.Printf("Could not create a parent window for client "+
			"with id '%d' because: %s", cid, err)
		logger.Error.Fatalf("In a state where no new windows can be created. " +
			"Unfortunately, we must exit.")
	}

	err = parent.CreateChecked(X.RootWin(), 0, 0, 1, 1,
		xproto.CwEventMask,
		xproto.EventMaskSubstructureRedirect|
			xproto.EventMaskButtonPress|xproto.EventMaskButtonRelease)
	if err != nil {
		return nil, err
	}

	err = xproto.ReparentWindowChecked(X.Conn(),
		cid, parent.Id, 0, 0).Check()
	if err != nil {
		return nil, err
	}

	return &Parent{parent}, nil
}

// CreateCursorExtra features all available parameters to creating a cursor.
// It will return an error if there is a problem with any of the requests
// made to create the cursor.
// (This implies each request is a checked request. The performance loss is
// probably acceptable since cursors should be created once and reused.)
func CreateCursorExtra(xu *xgbutil.XUtil, cursor, foreRed, foreGreen,
	foreBlue, backRed, backGreen, backBlue uint16) (xproto.Cursor, error) {

	fontId, err := xproto.NewFontId(xu.Conn())
	if err != nil {
		return 0, err
	}

	cursorId, err := xproto.NewCursorId(xu.Conn())
	if err != nil {
		return 0, err
	}

	err = xproto.OpenFontChecked(xu.Conn(), fontId,
		uint16(len("cursor")), "cursor").Check()
	if err != nil {
		return 0, err
	}

	err = xproto.CreateGlyphCursorChecked(xu.Conn(), cursorId, fontId, fontId,
		cursor, cursor+1,
		foreRed, foreGreen, foreBlue,
		backRed, backGreen, backBlue).Check()
	if err != nil {
		return 0, err
	}

	err = xproto.CloseFontChecked(xu.Conn(), fontId).Check()
	if err != nil {
		return 0, err
	}

	return cursorId, nil
}

// NewDrawable converts an X drawable into a xgraphics.Image.
// This is used in NewIcccmIcon.
func NewDrawable(X *xgbutil.XUtil, did xproto.Drawable) (*Image, error) {
	// Get the geometry of the pixmap for use in the GetImage request.
	pgeom, err := xwindow.RawGeometry(X, xproto.Drawable(did))
	if err != nil {
		return nil, err
	}

	// Get the image data for each pixmap.
	pixmapData, err := xproto.GetImage(X.Conn(), xproto.ImageFormatZPixmap,
		did,
		0, 0, uint16(pgeom.Width()), uint16(pgeom.Height()),
		(1<<32)-1).Reply()
	if err != nil {
		return nil, err
	}

	// Now create the xgraphics.Image and populate it with data from
	// pixmapData and maskData.
	ximg := New(X, image.Rect(0, 0, pgeom.Width(), pgeom.Height()))

	// We'll try to be a little flexible with the image format returned,
	// but not completely flexible.
	err = readDrawableData(X, ximg, did, pixmapData,
		pgeom.Width(), pgeom.Height())
	if err != nil {
		return nil, err
	}

	return ximg, nil
}

// When a cross is declared in its object literal form, it may not have the appropriate window.
// this function creates a new X11 window for the cross with the correct geometry depending
// on its Icon* parameters.
func (c *Cross) CreateWindow(X *xgbutil.XUtil, icons_per_direction int, bg_color uint32) (*xwindow.Window, error) {

	// calculate the dimensions of the spars of our cross +
	// width/height reflect the vertical-orientation rectangle
	width := c.IconMargin*2 + c.IconSize
	// padding between the icons, margin on the edges
	height := c.IconSize*icons_per_direction + c.IconPadding*(icons_per_direction-1) + c.IconMargin*2

	// intitialize a basic window for the cross
	win, err := xwindow.Generate(X)
	if err != nil {
		return nil, err
	}

	win.Create(X.RootWin(), 0, 0, height, height,
		xproto.CwBackPixel|xproto.CwOverrideRedirect, bg_color, 1)

	// the rects we will be adding together to form the shape of the cross
	vert := xrect.New(0, 0, width, height)
	horiz := xrect.New(0, 0, height, width)
	struts := []xrect.Rect{vert, horiz}

	geom, err := win.Geometry()
	if err != nil {
		return nil, err
	}

	// center struts over window
	x, y := util.CenterChild(vert, geom)
	vert.XSet(x)
	vert.YSet(y)
	x, y = util.CenterChild(horiz, geom)
	horiz.XSet(x)
	horiz.YSet(y)

	// build the cross shape from our friendly rectangles
	err = ComposeShape(X, win.Id, struts)
	if err != nil {
		return nil, err
	}

	// add the window to our cross struct
	c.Window = win

	// create icons from our images
	clr := RGB(bg_color)
	if c.imagesToBecomeIcons != nil {
		icons := make(map[string]*Icon, len(c.imagesToBecomeIcons))
		for name, img := range c.imagesToBecomeIcons {
			icon := NewIcon(X, img, win.Id)
			icon.Background = clr
			icons[name] = icon
		}
		c.Icons = icons
	} else {
		return nil, errors.New("Cross: you must create crosses using the NewCross function (this cross has now iconsToBecomeImage)")
	}

	return win, nil
}

// GrabKeyboard grabs the entire keyboard.
// Returns whether GrabStatus is successful and an error if one is reported by
// XGB. It is possible to not get an error and the grab to be unsuccessful.
// The purpose of 'win' is that after a grab is successful, ALL Key*Events will
// be sent to that window. Make sure you have a callback attached :-)
func GrabKeyboard(xu *xgbutil.XUtil, win xproto.Window) error {
	reply, err := xproto.GrabKeyboard(xu.Conn(), false, win, 0,
		xproto.GrabModeAsync, xproto.GrabModeAsync).Reply()
	if err != nil {
		return fmt.Errorf("GrabKeyboard: Error grabbing keyboard on "+
			"window '%x': %s", win, err)
	}

	switch reply.Status {
	case xproto.GrabStatusSuccess:
		// all is well
	case xproto.GrabStatusAlreadyGrabbed:
		return fmt.Errorf("GrabKeyboard: Could not grab keyboard. " +
			"Status: AlreadyGrabbed.")
	case xproto.GrabStatusInvalidTime:
		return fmt.Errorf("GrabKeyboard: Could not grab keyboard. " +
			"Status: InvalidTime.")
	case xproto.GrabStatusNotViewable:
		return fmt.Errorf("GrabKeyboard: Could not grab keyboard. " +
			"Status: NotViewable.")
	case xproto.GrabStatusFrozen:
		return fmt.Errorf("GrabKeyboard: Could not grab keyboard. " +
			"Status: Frozen.")
	}
	return nil
}

// RootGeometry gets the geometry of the root window. It will panic on failure.
func RootGeometry(xu *xgbutil.XUtil) xrect.Rect {
	geom, err := RawGeometry(xu, xproto.Drawable(xu.RootWin()))
	if err != nil {
		panic(err)
	}
	return geom
}

// Generate is just like New, but generates a new X resource id for you.
// Geom is initialized to (0, 0) 1x1.
// It is possible for id generation to return an error, in which case, an
// error is returned here.
func Generate(xu *xgbutil.XUtil) (*Window, error) {
	wid, err := xproto.NewWindowId(xu.Conn())
	if err != nil {
		return nil, err
	}
	return New(xu, wid), nil
}

// Ungrab undoes Grab. It will handle all combinations od modifiers found
// in xevent.IgnoreMods.
func Ungrab(xu *xgbutil.XUtil, win xproto.Window,
	mods uint16, key xproto.Keycode) {

	for _, m := range xevent.IgnoreMods {
		xproto.UngrabKeyChecked(xu.Conn(), key, win, mods|m).Check()
	}
}

func newWindow(X *xgbutil.XUtil, width, height int) *xwindow.Window {
	var (
		err error
		win *xwindow.Window
	)
	win, err = xwindow.Generate(X)
	if err != nil {
		log.Fatal(err)
	}
	win.Create(X.RootWin(), 0, 0, width, height,
		xproto.CwBackPixel|xproto.CwEventMask,
		0, xproto.EventMaskButtonRelease)
	win.WMGracefulClose(
		func(w *xwindow.Window) {
			xevent.Detach(w.X, w.Id)
			mousebind.Detach(w.X, w.Id)
			w.Destroy()
			xevent.Quit(X)
		})

	win.Map()

	if err != nil {
		log.Fatal(err)
	}
	return win
}

// Ungrab undoes Grab. It will handle all combinations of modifiers found
// in xevent.IgnoreMods.
func Ungrab(xu *xgbutil.XUtil, win xproto.Window, mods uint16,
	button xproto.Button) {

	for _, m := range xevent.IgnoreMods {
		xproto.UngrabButtonChecked(xu.Conn(), byte(button), win, mods|m).Check()
	}
}

func newWindow(controlCh *controlCh, X *xgbutil.XUtil, width, height int) *xwindow.Window {
	var (
		err error
		win *xwindow.Window
	)

	win, err = xwindow.Generate(X)
	if err != nil {
		panic(err)
	}

	win.Create(X.RootWin(), 0, 0, width, height,
		xproto.CwBackPixel|xproto.CwEventMask,
		0, xproto.EventMaskButtonRelease)

	// Xorg application exits when the window is closed.
	win.WMGracefulClose(
		func(w *xwindow.Window) {
			xevent.Detach(w.X, w.Id)
			mousebind.Detach(w.X, w.Id)
			w.Destroy()
			xevent.Quit(X)
			controlCh.exit <- true
		})

	// In order to get ConfigureNotify events, we must listen to the window
	// using the 'StructureNotify' mask.
	win.Listen(xproto.EventMaskButtonPress |
		xproto.EventMaskButtonRelease |
		xproto.EventMaskKeyPress |
		xproto.EventMaskKeyRelease |
		xproto.EventMaskStructureNotify)
	win.Map()
	return win
}

// find the EWHM window under the mouse cursor
func FindManagedWindowUnderMouse(X *xgbutil.XUtil) (xproto.Window, error) {
	// construct a hashset of the managed windows
	clients, err := ewmh.ClientListGet(X)
	if err != nil {
		return 0, fmt.Errorf("FindUnderMouse: could not retrieve EWHM client list: %v", err)
	}

	managed := make(map[xproto.Window]bool, len(clients))
	for _, win := range clients {
		managed[win] = true
	}

	cur_window := X.RootWin()

	// descend the QueryTree to the first child that is a EWMH managed window
	for {
		// return the parent if it is an EWHM window
		if _, ok := managed[cur_window]; ok {
			return cur_window, nil
		}

		cur_window, _, err = FindNextUnderMouse(X, cur_window)
		if err != nil {
			break
		}
	}

	// we didn't find the window :(
	return 0, errors.New("FindUnderMouse: no EWMH window found under mouse")
}

func keyHandlers(X *xgbutil.XUtil,
	cycle *prompt.Cycle, items []*prompt.CycleItem) {

	geom := headGeom(X)

	keybind.KeyPressFun(
		func(X *xgbutil.XUtil, ev xevent.KeyPressEvent) {
			shown := cycle.Show(geom, cycleNext, items)
			if !shown {
				log.Fatal("Did not show cycle prompt.")
			}
			cycle.Next()
		}).Connect(X, X.RootWin(), cycleNext, true)
	keybind.KeyPressFun(
		func(X *xgbutil.XUtil, ev xevent.KeyPressEvent) {
			cycle.Next()
		}).Connect(X, cycle.GrabId(), cycleNext, true)

	keybind.KeyPressFun(
		func(X *xgbutil.XUtil, ev xevent.KeyPressEvent) {
			shown := cycle.Show(geom, cyclePrev, items)
			if !shown {
				log.Fatal("Did not show cycle prompt.")
			}
			cycle.Prev()
		}).Connect(X, X.RootWin(), cyclePrev, true)
	keybind.KeyPressFun(
		func(X *xgbutil.XUtil, ev xevent.KeyPressEvent) {
			cycle.Prev()
		}).Connect(X, cycle.GrabId(), cyclePrev, true)
}

// PhyiscalHeads returns the list of heads in a physical ordering.
// Namely, left to right then top to bottom. (Defined by (X, Y).)
// Xinerama must have been initialized, otherwise the xinerama.QueryScreens
// request will panic.
// PhysicalHeads also checks to make sure each rectangle has a unique (x, y)
// tuple, so as not to return the geometry of cloned displays.
// (At present moment, xgbutil initializes Xinerama automatically during
// initial connection.)
func PhysicalHeads(xu *xgbutil.XUtil) (Heads, error) {
	xinfo, err := xinerama.QueryScreens(xu.Conn()).Reply()
	if err != nil {
		return nil, err
	}

	hds := make(Heads, 0)
	for _, info := range xinfo.ScreenInfo {
		head := xrect.New(int(info.XOrg), int(info.YOrg),
			int(info.Width), int(info.Height))

		// Maybe Xinerama is enabled, but we have cloned displays...
		unique := true
		for _, h := range hds {
			if h.X() == head.X() && h.Y() == head.Y() {
				unique = false
				break
			}
		}

		if unique {
			hds = append(hds, head)
		}
	}

	sort.Sort(hds)
	return hds, nil
}

// _NET_DESKTOP_LAYOUT set
func DesktopLayoutSet(xu *xgbutil.XUtil, orientation, columns, rows,
	startingCorner uint) error {

	return xprop.ChangeProp32(xu, xu.RootWin(), "_NET_DESKTOP_LAYOUT",
		"CARDINAL", orientation, columns, rows,
		startingCorner)
}

// GetFormat searches SetupInfo for a Format matching the depth provided.
func GetFormat(X *xgbutil.XUtil, depth byte) *xproto.Format {
	for _, pixForm := range X.Setup().PixmapFormats {
		if pixForm.Depth == depth {
			return &pixForm
		}
	}
	return nil
}