package objects

import "log"
import "image"
import "image/color"
import "git.tebibyte.media/tomo/tomo"
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/objects/layouts"

// Swatch displays a color, allowing the user to edit it by clicking on it.
type Swatch struct {
	tomo.CanvasBox
	value color.Color
	editing bool
	label string
	on struct {
		valueChange event.FuncBroadcaster
	}
}

// NewSwatch creates a new swatch with the given color.
func NewSwatch (value color.Color) *Swatch {
	swatch := &Swatch {
		CanvasBox: tomo.NewCanvasBox(),
	}
	swatch.SetRole(tomo.R("objects", "Swatch", ""))
	swatch.SetDrawer(swatch)
	swatch.SetValue(value)
	
	swatch.OnMouseUp(swatch.handleMouseUp)
	swatch.OnKeyUp(swatch.handleKeyUp)
	swatch.SetFocusable(true)
	return swatch
}

// SetValue sets the color of the swatch.
func (this *Swatch) SetValue (value color.Color) {
	this.value = value
	if value == nil { value = color.Transparent }
	this.Invalidate()
}

// Value returns the color of the swatch.
func (this *Swatch) Value () color.Color {
	return this.value
}

// RGBA satisfies the color.Color interface
func (this *Swatch) RGBA () (r, g, b, a uint32) {
	return this.value.RGBA()
}

// OnValueChange specifies a function to be called when the swatch's color
// changes.
func (this *Swatch) OnValueChange (callback func ()) event.Cookie {
	return this.on.valueChange.Connect(callback)
}

// Choose creates a modal that allows the user to edit the color of the swatch.
func (this *Swatch) Choose () {
	if this.editing { return }

	var err    error
	var window tomo.Window
	if parent := this.Window(); parent != nil {
		window, err = parent.NewModal(image.Rectangle { })
	} else {
		window, err = tomo.NewWindow(image.Rectangle { })
	}
	if err != nil {
		log.Println("objects: could not create swatch modal:", err)
		return
	}
	if this.label == "" {
		window.SetTitle("Select Color")
	} else {
		window.SetTitle(this.label)
	}
	
	colorPicker := NewColorPicker(this.Value())
	colorPicker.OnValueChange(func () {
		this.userSetValue(colorPicker.Value())
	})
	
	colorMemory  := this.value
	cancelButton := NewButton("Cancel")
	cancelButton.SetIcon(tomo.IconDialogCancel)
	cancelButton.OnClick(func () {
		this.userSetValue(colorMemory)
		window.Close()
	})
	okButton := NewButton("OK")
	okButton.SetFocused(true)
	okButton.SetIcon(tomo.IconDialogOkay)
	okButton.OnClick(func () {
		window.Close()
	})
	
	controlRow := NewInnerContainer (
		layouts.ContractHorizontal,
		cancelButton,
		okButton)
	controlRow.SetAlign(tomo.AlignEnd, tomo.AlignMiddle)
	window.SetRoot(NewOuterContainer (
		layouts.Column { true, false },
		colorPicker,
		controlRow))
	window.OnClose(func () {
		this.editing = false
	})
	this.editing = true
	window.SetVisible(true)
}

func (this *Swatch) Draw (can canvas.Canvas) {
	pen := can.Pen()
	
	// transparency slash
	pen.Stroke(color.RGBA { R: 255, A: 255 })
	pen.StrokeWeight(1)
	pen.Path(this.Bounds().Min, this.Bounds().Max)
	
	// color
	if this.value != nil {
		pen.StrokeWeight(0)
		pen.Fill(this.value)
		pen.Rectangle(this.Bounds())
	}
}

func (this *Swatch) userSetValue (value color.Color) {
	this.SetValue(value)
	this.on.valueChange.Broadcast()
}

func (this *Swatch) handleKeyUp (key input.Key, numberPad bool) {
	if key != input.KeyEnter && key != input.Key(' ') { return }
	this.Choose()
}

func (this *Swatch) handleMouseUp (button input.Button) {
	if button != input.ButtonLeft { return }
	if this.MousePosition().In(this.Bounds()) {
		this.Choose()
	}
}