package x

import "image"
import "image/color"
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"

type box struct {
	backend *Backend
	window  *window

	bounds  image.Rectangle
	minSize image.Point

	padding tomo.Inset
	border  []tomo.Border
	color   color.Color

	dndData   data.Data
	dndAccept []data.Mime
	focused   bool
	focusable bool

	drawClean   bool
	layoutClean bool

	drawer canvas.Drawer

	on struct {
		focusEnter event.FuncBroadcaster
		focusLeave event.FuncBroadcaster
		dndEnter   event.FuncBroadcaster
		dndLeave   event.FuncBroadcaster
		dndDrop    event.Broadcaster[func (data.Data)]
		mouseEnter event.FuncBroadcaster
		mouseLeave event.FuncBroadcaster
		mouseMove  event.FuncBroadcaster
		mouseDown  event.Broadcaster[func (input.Button)]
		mouseUp    event.Broadcaster[func (input.Button)]
		scroll     event.Broadcaster[func (float64, float64)]
		keyDown    event.Broadcaster[func (input.Key, bool)]
		keyUp      event.Broadcaster[func (input.Key, bool)]
	}
}

func (backend *Backend) NewBox() tomo.Box {
	box := &box {
		backend: backend,
	}
	box.drawer = box
	return box
}

func (this *box) Box () tomo.Box {
	return this
}

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

func (this *box) Bounds () image.Rectangle {
	return this.bounds
}

func (this *box) InnerBounds () image.Rectangle {
	innerBounds := this.padding.Apply(this.bounds)
	for _, border := range this.border {
		innerBounds = border.Width.Apply(innerBounds)
	}
	return innerBounds
}

func (this *box) SetBounds (bounds image.Rectangle) {
	if this.bounds == bounds { return }
	this.bounds = bounds
	this.invalidateLayout()
}

func (this *box) SetColor (c color.Color) {
	if this.color == c { return }
	this.color = c
	this.invalidateDraw()
}

func (this *box) SetBorder (border ...tomo.Border) {
	this.border = border
	this.invalidateLayout()
}

func (this *box) SetMinimumSize (width, height int) {
	this.minSize = image.Pt(width, height)
	if this.bounds.Dx() < width || this.bounds.Dy() < height {
		this.invalidateLayout()
	}
}

func (this *box) SetPadding (padding tomo.Inset) {
	if this.padding == padding { return }
	this.padding = padding
	this.invalidateLayout()
}

func (this *box) SetDNDData (dat data.Data) {
	this.dndData = dat
}

func (this *box) SetDNDAccept (types ...data.Mime) {
	this.dndAccept = types
}

func (this *box) SetFocused (focused bool) {
	if this.Focused () && !focused {
		this.window.focus(nil)
	} else if !this.Focused() && focused {
		this.window.focus(this)
	}
}

func (this *box) SetFocusable (focusable bool) {
	if this.focusable == focusable { return }
	this.focusable = focusable
	if !focusable {
		this.SetFocused(false)
	}
}

func (this *box) Focused () bool {
	return this == this.window.focused
}

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

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

// ----- event handlers ----------------------------------------------------- //
func (this *box) OnFocusEnter (callback func()) event.Cookie {
	return this.on.focusEnter.Connect(callback)
}
func (this *box) OnFocusLeave (callback func()) event.Cookie {
	return this.on.focusLeave.Connect(callback)
}
func (this *box) OnDNDEnter (callback func()) event.Cookie {
	return this.on.dndEnter.Connect(callback)
}
func (this *box) OnDNDLeave (callback func()) event.Cookie {
	return this.on.dndLeave.Connect(callback)
}
func (this *box) OnDNDDrop (callback func(data.Data)) event.Cookie {
	return this.on.dndDrop.Connect(callback)
}
func (this *box) OnMouseEnter (callback func()) event.Cookie {
	return this.on.mouseEnter.Connect(callback)
}
func (this *box) OnMouseLeave (callback func()) event.Cookie {
	return this.on.mouseLeave.Connect(callback)
}
func (this *box) OnMouseMove (callback func()) event.Cookie {
	return this.on.mouseMove.Connect(callback)
}
func (this *box) OnMouseDown (callback func(input.Button)) event.Cookie {
	return this.on.mouseDown.Connect(callback)
}
func (this *box) OnMouseUp (callback func(input.Button)) event.Cookie {
	return this.on.mouseUp.Connect(callback)
}
func (this *box) OnScroll (callback func(deltaX, deltaY float64)) event.Cookie {
	return this.on.scroll.Connect(callback)
}
func (this *box) OnKeyDown (callback func(key input.Key, numberPad bool)) event.Cookie {
	return this.on.keyDown.Connect(callback)
}
func (this *box) OnKeyUp (callback func(key input.Key, numberPad bool)) event.Cookie {
	return this.on.keyUp.Connect(callback)
}
// -------------------------------------------------------------------------- //

func (this *box) Draw (can canvas.Canvas) {
	pen := can.Pen()

	bounds := this.bounds
	for _, border := range this.border {
		pen.Fill(border.Color[tomo.SideTop])
		pen.Rectangle(image.Rect (
			bounds.Min.X,
			bounds.Min.Y,
			bounds.Max.X,
			bounds.Min.Y + border.Width[tomo.SideTop]))
		pen.Fill(border.Color[tomo.SideBottom])
		pen.Rectangle(image.Rect (
			bounds.Min.X,
			bounds.Max.Y - border.Width[tomo.SideBottom],
			bounds.Max.X,
			bounds.Max.Y))
		pen.Fill(border.Color[tomo.SideLeft])
		pen.Rectangle(image.Rect (
			bounds.Min.X,
			bounds.Min.Y + border.Width[tomo.SideTop],
			bounds.Min.X + border.Width[tomo.SideLeft],
			bounds.Max.Y - border.Width[tomo.SideBottom]))
		pen.Fill(border.Color[tomo.SideRight])
		pen.Rectangle(image.Rect (
			bounds.Max.X - border.Width[tomo.SideRight],
			bounds.Min.Y + border.Width[tomo.SideTop],
			bounds.Max.X,
			bounds.Max.Y - border.Width[tomo.SideBottom]))

		bounds = border.Width.Apply(bounds)
	}
	pen.Fill(this.color)
	pen.Rectangle(bounds)
}

func (this *box) invalidateDraw () {
	this.drawClean = false
}

func (this *box) invalidateLayout () {
	this.invalidateDraw()
	this.layoutClean = false
}