package x

import "image"
// import "errors"

import "git.tebibyte.media/tomo/tomo"
import "git.tebibyte.media/tomo/x/canvas"
import "git.tebibyte.media/tomo/tomo/data"
import "git.tebibyte.media/tomo/tomo/input"
import "git.tebibyte.media/tomo/tomo/event"
import "git.tebibyte.media/tomo/tomo/canvas"

import "github.com/jezek/xgb/xproto"
import "github.com/jezek/xgbutil/ewmh"
import "github.com/jezek/xgbutil/icccm"
// import "github.com/jezek/xgbutil/xprop"
import "github.com/jezek/xgbutil/xevent"
import "github.com/jezek/xgbutil/xwindow"
import "github.com/jezek/xgbutil/keybind"
import "github.com/jezek/xgbutil/mousebind"
import "github.com/jezek/xgbutil/xgraphics"

type mainWindow struct { *window }
type window struct {
	backend *Backend
	xWindow *xwindow.Window
	xImage  *xgraphics.Image
	xCanvas *xcanvas.Canvas

	title string

	modalParent *window
	hasModal    bool
	shy         bool
	visible     bool

	metrics struct {
		bounds image.Rectangle
	}

	modifiers     input.Modifiers
	mousePosition image.Point
	drags         [10]anyBox

	onClose event.FuncBroadcaster

	root    anyBox
	focused anyBox
	hovered anyBox

	// TODO: needMinimum and needLayout should be priority queues. for the
	// minimums, we need to start at the deeper parts of the layout tree and
	// go upward towards the top. for the layouts, we need to start at the
	// top of the layout tree and progressively go deeper. this will
	// eliminate redundant layout calculations.

	needMinimum  boxSet
	needLayout   boxSet
	needDraw     boxSet
	needRedo     bool
	minimumClean bool
}

func (backend *Backend) NewWindow (
	bounds image.Rectangle,
) (
	output tomo.MainWindow,
	err error,
) {
	backend.assert()
	window, err := backend.newWindow(bounds, false)
	
	output = mainWindow { window: window }
	return output, err
}

func (backend *Backend) NewPlainWindow (
	bounds image.Rectangle,
) (
	output tomo.MainWindow,
	err error,
) {
	backend.assert()
	window, err := backend.newWindow(bounds, false)
	window.setType("dock")
	
	output = mainWindow { window: window }
	return output, err
}

func (backend *Backend) newWindow (
	bounds   image.Rectangle,
	override bool,
) (
	output *window,
	err error,
) {
	if bounds.Dx() == 0 { bounds.Max.X = bounds.Min.X + 8 }
	if bounds.Dy() == 0 { bounds.Max.Y = bounds.Min.Y + 8 }
	
	window := &window { backend: backend }

	window.xWindow, err = xwindow.Generate(backend.x)
	if err != nil { return }

	if override {
		err = window.xWindow.CreateChecked (
			backend.x.RootWin(),
			bounds.Min.X, bounds.Min.Y, bounds.Dx(), bounds.Dy(),
			xproto.CwOverrideRedirect, 1)
	} else {
		err = window.xWindow.CreateChecked (
			backend.x.RootWin(),
			bounds.Min.X, bounds.Min.Y, bounds.Dx(), bounds.Dy(), 0)
	}
	if err != nil { return }
	
	err = window.xWindow.Listen (
		xproto.EventMaskExposure,
		xproto.EventMaskStructureNotify,
		xproto.EventMaskPropertyChange,
		xproto.EventMaskPointerMotion,
		xproto.EventMaskKeyPress,
		xproto.EventMaskKeyRelease,
		xproto.EventMaskButtonPress,
		xproto.EventMaskButtonRelease)
	if err != nil { return }

	window.xWindow.WMGracefulClose (func (xWindow *xwindow.Window) {
		window.Close()
	})

	xevent.ExposeFun(window.handleExpose).
		Connect(backend.x, window.xWindow.Id)
	xevent.ConfigureNotifyFun(window.handleConfigureNotify).
		Connect(backend.x, window.xWindow.Id)
	xevent.KeyPressFun(window.handleKeyPress).
		Connect(backend.x, window.xWindow.Id)
	xevent.KeyReleaseFun(window.handleKeyRelease).
		Connect(backend.x, window.xWindow.Id)
	xevent.ButtonPressFun(window.handleButtonPress).
		Connect(backend.x, window.xWindow.Id)
	xevent.ButtonReleaseFun(window.handleButtonRelease).
		Connect(backend.x, window.xWindow.Id)
	xevent.MotionNotifyFun(window.handleMotionNotify).
		Connect(backend.x, window.xWindow.Id)
	// xevent.SelectionNotifyFun(window.handleSelectionNotify).
		// Connect(backend.x, window.xWindow.Id)
	// xevent.PropertyNotifyFun(window.handlePropertyNotify).
		// Connect(backend.x, window.xWindow.Id)
	// xevent.SelectionClearFun(window.handleSelectionClear).
		// Connect(backend.x, window.xWindow.Id)
	// xevent.SelectionRequestFun(window.handleSelectionRequest).
		// Connect(backend.x, window.xWindow.Id)
	
	window.metrics.bounds = bounds
	window.doMinimumSize()

	backend.windows[window.xWindow.Id] = window

	output = window
	return
}

func (window *window) SetTitle (title string) {
	window.title = title
	ewmh .WmNameSet     (window.backend.x, window.xWindow.Id, title)
	icccm.WmNameSet     (window.backend.x, window.xWindow.Id, title)
	icccm.WmIconNameSet (window.backend.x, window.xWindow.Id, title)
}

func (window *window) SetIcon (sizes ...image.Image) {
	wmIcons := []ewmh.WmIcon { }
	
	for _, icon := range sizes {
		width  := icon.Bounds().Max.X
		height := icon.Bounds().Max.Y
		wmIcon := ewmh.WmIcon {
			Width:  uint(width),
			Height: uint(height),
			Data:   make([]uint, width * height),
		}

		// manually convert image data beacuse of course we have to do
		// this
		index := 0
		for y := 0; y < height; y ++ {
		for x := 0; x < width;  x ++ {
			r, g, b, a := icon.At(x, y).RGBA()
			r >>= 8
			g >>= 8
			b >>= 8
			a >>= 8
			wmIcon.Data[index] =
				(uint(a) << 24) |
				(uint(r) << 16) |
				(uint(g) << 8)  |
				(uint(b) << 0)
			index ++
		}}
		
		wmIcons = append(wmIcons, wmIcon)
	}

	ewmh.WmIconSet (
		window.backend.x,
		window.xWindow.Id,
		wmIcons)
}

func (window *window) NewMenu (bounds image.Rectangle) (tomo.Window, error) {
	menu, err := window.backend.newWindow (
		bounds.Add(window.metrics.bounds.Min), true)
	menu.shy = true
	icccm.WmTransientForSet (
		window.backend.x,
		menu.xWindow.Id,
		window.xWindow.Id)
	menu.setType("POPUP_MENU")
	// menu.inheritProperties(window)
	return menu, err
}

func (window *window) NewModal (bounds image.Rectangle) (tomo.Window, error) {
	modal, err := window.backend.newWindow (
		bounds.Add(window.metrics.bounds.Min), false)
	icccm.WmTransientForSet (
		window.backend.x,
		modal.xWindow.Id,
		window.xWindow.Id)
	ewmh.WmStateSet (
		window.backend.x,
		modal.xWindow.Id,
		[]string { "_NET_WM_STATE_MODAL" })
	modal.modalParent = window
	window.hasModal    = true
	// modal.inheritProperties(window)
	return modal, err
}

func (window mainWindow) NewChild (bounds image.Rectangle) (tomo.Window, error) {
	child, err := window.backend.newWindow (
		bounds.Add(window.metrics.bounds.Min), false)
	if err != nil { return nil, err }
	child.setClientLeader(window.window)
	window.setClientLeader(window.window)
	icccm.WmTransientForSet (
		window.backend.x,
		window.xWindow.Id,
		window.xWindow.Id)
	window.setType("UTILITY")
	// window.inheritProperties(window.window)
	return window, err
}

func (window *window) Widget () (tomo.Window, error) {
	// TODO
	return nil, nil
}

func (window *window) Copy (data.Data) {
	// TODO
}

func (window *window) Paste (callback func (data.Data, error), accept ...data.Mime) {
	// TODO
}

func (window *window) SetVisible (visible bool) {
	if window.visible == visible { return }
	window.visible = visible
	
	if window.visible {
		window.xWindow.Map()
		if window.shy { window.grabInput() }
	} else {
		window.xWindow.Unmap()
		if window.shy { window.ungrabInput() }
	}
}

func (window *window) Visible () bool {
	return window.visible
}

func (window *window) Close () {
	xevent   .Detach(window.backend.x, window.xWindow.Id)
	keybind  .Detach(window.backend.x, window.xWindow.Id)
	mousebind.Detach(window.backend.x, window.xWindow.Id)

	window.onClose.Broadcast()
	if window.modalParent != nil {
		// we are a modal dialog, so unlock the parent
		window.modalParent.hasModal = false
	}
	window.SetVisible(false)
	window.SetRoot(nil)
	delete(window.backend.windows, window.xWindow.Id)
	window.xWindow.Destroy()
}

func (window *window) OnClose (callback func ()) event.Cookie {
	return window.onClose.Connect(callback)
}

func (window *window) grabInput () {
	keybind.GrabKeyboard(window.backend.x, window.xWindow.Id)
	mousebind.GrabPointer (
		window.backend.x,
		window.xWindow.Id,
		window.backend.x.RootWin(), 0)
}

func (window *window) ungrabInput () {
	keybind.UngrabKeyboard(window.backend.x)
	mousebind.UngrabPointer(window.backend.x)
}

func (window *window) setType (ty string) error {
	return ewmh.WmWindowTypeSet (
		window.backend.x,
		window.xWindow.Id,
		[]string { "_NET_WM_WINDOW_TYPE_" + ty })
}

func (window *window) setClientLeader (leader *window) error {
	hints, _ := icccm.WmHintsGet(window.backend.x, window.xWindow.Id)
	if hints == nil {
		hints = &icccm.Hints { }
	}
	hints.Flags |= icccm.HintWindowGroup
	hints.WindowGroup = leader.xWindow.Id
	return icccm.WmHintsSet (
		window.backend.x,
		window.xWindow.Id,
		hints)
}

func (window *window) reallocateCanvas () {
	var previousWidth, previousHeight int
	if window.xCanvas != nil {
		previousWidth  = window.xCanvas.Bounds().Dx()
		previousHeight = window.xCanvas.Bounds().Dy()
	}
	
	newWidth  := window.metrics.bounds.Dx()
	newHeight := window.metrics.bounds.Dy()
	larger    := newWidth > previousWidth || newHeight > previousHeight
	smaller   := newWidth < previousWidth / 2 || newHeight < previousHeight / 2

	allocStep := 128
	
	if larger || smaller {
		if window.xCanvas != nil {
			window.xCanvas.Destroy()
		}
		window.xCanvas = xcanvas.NewCanvasFrom(xgraphics.New (
			window.backend.x,
			image.Rect (
				0, 0,
				(newWidth  / allocStep + 1) * allocStep,
				(newHeight / allocStep + 1) * allocStep)))
		window.xCanvas.CreatePixmap()
	}

	window.needRedo = true
}

func (window *window) pushAll () {
	if window.xCanvas != nil {
		window.xCanvas.Push(window.xWindow.Id)
	}
}

func (window *window) pushRegion (region image.Rectangle) {
	if window.xCanvas == nil {
		return
	}
	
	subCanvas := window.xCanvas.SubCanvas(region)
	if subCanvas == nil {
		return
	}
	subCanvas.(*xcanvas.Canvas).Push(window.xWindow.Id)
}

func (window *window) drawBackgroundPart (canvas.Canvas) {
	// no-op for now? maybe eventually windows will be able to have a
	// background
}

func (window *window) doMinimumSize () {
	window.minimumClean = true

	size := image.Point { }
	if window.root != nil {
		size = window.root.MinimumSize()
	}
	
	if size.X < 8 { size.X = 8 }
	if size.Y < 8 { size.Y = 8 }
	icccm.WmNormalHintsSet (
		window.backend.x,
		window.xWindow.Id,
		&icccm.NormalHints {
			Flags:     icccm.SizeHintPMinSize,
			MinWidth:  uint(size.X),
			MinHeight: uint(size.Y),
		})
	newWidth  := window.metrics.bounds.Dx()
	newHeight := window.metrics.bounds.Dy()
	if newWidth  < size.X { newWidth  = size.X }
	if newHeight < size.Y { newHeight = size.Y }
	if newWidth != window.metrics.bounds.Dx() ||
		newHeight != window.metrics.bounds.Dy() {
		window.xWindow.Resize(newWidth, newHeight)
	}
}