package stone

import "image"

// Application represents an application.
type Application struct {
	DamageBuffer
	
	title string
	icons []image.Image
	backend Backend
	config Config
	callbackManager CallbackManager
	imageManager ImageManager
}

// Run initializes the application, starts it, and then returns a channel that
// broadcasts events. If no suitable backend can be found, an error is returned.
func (application *Application) Run () (
	err     error,
) {
	// default values for certain parameters
	width, height := application.Size()
	if width  < 1 { width  = 80 }
	if height < 1 { height = 20 }
	application.DamageBuffer.SetSize(width, height)

	application.config.load()

	application.backend, err = instantiateBackend(application)
	if err != nil { return }
	
	application.backend.Run()
	return
}

func (application *Application) OnQuit (
	onQuit func (),
) {
	application.callbackManager.onQuit = onQuit
}

func (application *Application) OnPress (
	onPress func (button Button),
) {
	application.callbackManager.onPress = onPress
}

func (application *Application) OnRelease (
	onRelease func (button Button),
) {
	application.callbackManager.onRelease = onRelease
}

func (application *Application) OnResize (
	onResize func (),
) {
	application.callbackManager.onResize = onResize
}

func (application *Application) OnMouseMove (
	onMouseMove func (x, y int),
) {
	application.callbackManager.onMouseMove = onMouseMove
}

func (application *Application) OnScroll (
	onScroll func (x, y int),
) {
	application.callbackManager.onScroll = onScroll
}

func (application *Application) OnStart (
	onStart func (),
) {
	application.callbackManager.onStart = onStart
}

// Draw "commits" changes made in the buffer to the display.
func (application *Application) Draw () {
	application.backend.Draw()
}

// SetTitle sets the application's title. If in a window, it will appear as the
// window's name.
func (application *Application) SetTitle (title string) (err error) {
	application.title = title
	if application.backend != nil {
		err = application.backend.SetTitle(title)
	}

	return 
}

// Title returns the application's title.
func (application *Application) Title () (title string) {
	title = application.title
	return
}

// SetIcon takes in a list of different sizes of an icon, and sets it as the
// application's icon.
func (application *Application) SetIcon (sizes []image.Image) (err error) {
	application.icons = sizes
	if application.backend != nil {
		err = application.backend.SetIcon(sizes)
	}

	return
}

// Icon returns all available sizes of the application's icon. If there is no
// icon, nil is returned.
func (application *Application) Icon () (sizes []image.Image) {
	sizes = application.icons
	return
}

// Config returns a pointer to the application's configuration.
func (application *Application) Config () (config *Config) {
	config = &application.config
	return
}

// AddImage adds a new image buffer and returns a pointer to it.
func (application *Application) NewImage () (im *ColorImage) {
	cellWidth, cellHeight := application.backend.CellMetrics()
	im = &ColorImage {
		cellWidth:  cellWidth,
		cellHeight: cellHeight,
	}
	application.imageManager.Add(im)
	return
}

// Remove removes the specified image buffer, if the application has it. If the
// image was found and removed, removed will be true.
func (application *Application) RemoveImage (im *ColorImage) (removed bool) {
	removed = application.imageManager.Remove(im)
	return
}