package x

import "image"

import "git.tebibyte.media/tomo/tomo"
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 "git.tebibyte.media/tomo/backend/x/canvas"
import "git.tebibyte.media/tomo/backend/internal/system"

import "github.com/jezek/xgb/xproto"
import "github.com/jezek/xgbutil/ewmh"
import "github.com/jezek/xgbutil/icccm"
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 window struct {
	backend   *Backend
	hierarchy *system.Hierarchy
	xWindow   *xwindow.Window
	xImage    *xgraphics.Image
	xCanvas   *xcanvas.Canvas

	title string

	leader      *window
	modalParent *window
	hasModal    bool
	shy         bool
	visible     bool
	resizeX     bool
	resizeY     bool

	metrics struct {
		bounds      image.Rectangle // bounds, including frame
		innerBounds image.Rectangle // bounds of the drawable area
	}

	onClose event.FuncBroadcaster
}

type windowLink struct {
	window *window
}

func (this *windowLink) GetWindow () tomo.Window {
	return this.window
}

func (this *windowLink) PushRegion (region image.Rectangle) {
	this.window.pushRegion(region)
}

func (this *windowLink) PushAll () {
	this.window.pushAll()
}

func (this *windowLink) NotifyMinimumSizeChange () {
	this.window.doMinimumSize()
}

func (this *Backend) NewWindow (
	bounds image.Rectangle,
) (
	output tomo.Window,
	err error,
) {
	this.assert()
	return this.newWindow(bounds, false)
}

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

func (this *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: this   }
	link   := &windowLink { window:  window }
	window.hierarchy = this.system.NewHierarchy(link)
	window.leader    = window
	window.resizeX   = true
	window.resizeY   = true

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

	if override {
		err = window.xWindow.CreateChecked (
			this.x.RootWin(),
			bounds.Min.X, bounds.Min.Y, bounds.Dx(), bounds.Dy(),
			xproto.CwOverrideRedirect, 1)
	} else {
		err = window.xWindow.CreateChecked (
			this.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(this.x, window.xWindow.Id)
	xevent.ConfigureNotifyFun(window.handleConfigureNotify).
		Connect(this.x, window.xWindow.Id)
	xevent.KeyPressFun(window.handleKeyPress).
		Connect(this.x, window.xWindow.Id)
	xevent.KeyReleaseFun(window.handleKeyRelease).
		Connect(this.x, window.xWindow.Id)
	xevent.ButtonPressFun(window.handleButtonPress).
		Connect(this.x, window.xWindow.Id)
	xevent.ButtonReleaseFun(window.handleButtonRelease).
		Connect(this.x, window.xWindow.Id)
	xevent.MotionNotifyFun(window.handleMotionNotify).
		Connect(this.x, window.xWindow.Id)
	// xevent.SelectionNotifyFun(window.handleSelectionNotify).
		// Connect(this.x, window.xWindow.Id)
	// xevent.PropertyNotifyFun(window.handlePropertyNotify).
		// Connect(this.x, window.xWindow.Id)
	// xevent.SelectionClearFun(window.handleSelectionClear).
		// Connect(this.x, window.xWindow.Id)
	// xevent.SelectionRequestFun(window.handleSelectionRequest).
		// Connect(this.x, window.xWindow.Id)
	
	window.metrics.innerBounds = bounds
	window.doMinimumSize()

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

	output = window
	return
}

func (this *window) Bounds () image.Rectangle {
	return this.metrics.bounds.Sub(this.metrics.innerBounds.Min)
}

func (this *window) InnerBounds () image.Rectangle {
	return this.metrics.innerBounds.Sub(this.metrics.innerBounds.Min)
}

func (this *window) SetRoot (root tomo.Object) {
	if root == nil {
		this.hierarchy.SetRoot(nil)
	} else {
		this.hierarchy.SetRoot(root.GetBox())
	}
}

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

func (this *window) SetIcon (icon tomo.Icon) {
	textures := []canvas.Texture {
		icon.Texture(tomo.IconSizeSmall),
		icon.Texture(tomo.IconSizeMedium),
		icon.Texture(tomo.IconSizeLarge),
	}
	
	wmIcons := []ewmh.WmIcon { }

	for _, icon := range textures {
		icon := xcanvas.AssertTexture(icon)
		
		bounds := icon.Bounds()
		width  := bounds.Dx()
		height := bounds.Dy()
		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 := bounds.Min.Y; y < bounds.Max.Y; y ++ {
		for x := bounds.Min.X; x < bounds.Max.X; x ++ {
			pixel := icon.BGRAAt(x, y)
			wmIcon.Data[index] =
				(uint(pixel.A) << 24) |
				(uint(pixel.R) << 16) |
				(uint(pixel.G) << 8)  |
				(uint(pixel.B) << 0)
			index ++
		}}
		
		wmIcons = append(wmIcons, wmIcon)
	}

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

func (this *window) SetResizable (x, y bool) {
	if this.resizeX == x && this.resizeY == y { return }
	this.resizeX = x
	this.resizeY = y
	this.doMinimumSize()
}

func (this *window) SetBounds (bounds image.Rectangle) {
	this.xWindow.WMMoveResize (
		bounds.Min.X, bounds.Min.Y,
		bounds.Min.X + bounds.Dx(),
		bounds.Min.Y + bounds.Dy())
}

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

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

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

func (this *window) Modifiers () input.Modifiers {
	return this.hierarchy.Modifiers()
}

func (this *window) MousePosition () image.Point {
	return this.hierarchy.MousePosition()
}

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

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

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

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

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

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

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

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

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

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

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

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

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

	this.hierarchy.SetCanvas(this.xCanvas.SubCanvas (
		this.metrics.innerBounds.Sub(this.metrics.innerBounds.Min)))
}

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

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

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

func (this *window) doMinimumSize () {
	size := this.hierarchy.MinimumSize()
	
	if size.X < 8 { size.X = 8 }
	if size.Y < 8 { size.Y = 8 }

	hints := icccm.NormalHints {
		Flags:     icccm.SizeHintPMinSize,
		MinWidth:  uint(size.X),
		MinHeight: uint(size.Y),
		// now you can tell your friends that the max size of a Tomo
		// window under X when one of the dimensions is constrained is
		// 99999999999
		MaxWidth:  uint(99999999999),
		MaxHeight: uint(99999999999),
	}
	if !this.resizeX {
		hints.Flags   |= icccm.SizeHintPMaxSize
		hints.MaxWidth = uint(size.X)
	}
	if !this.resizeY {
		hints.Flags    |= icccm.SizeHintPMaxSize
		hints.MaxHeight = uint(size.Y)
	}
	
	icccm.WmNormalHintsSet (
		this.backend.x,
		this.xWindow.Id,
		&hints)
	newWidth  := this.metrics.innerBounds.Dx()
	newHeight := this.metrics.innerBounds.Dy()
	if newWidth  < size.X { newWidth  = size.X }
	if newHeight < size.Y { newHeight = size.Y }
	if newWidth != this.metrics.innerBounds.Dx() ||
		newHeight != this.metrics.innerBounds.Dy() {
		this.xWindow.Resize(newWidth, newHeight)
	}
}