// The UI manager.  This manages the components that make up the UI and dispatches
// events.

package ui

// The UI manager
type Ui struct {
	// The root component
	rootComponent    UiComponent
	focusedComponent FocusableComponent

	drawContext *DrawContext
	driver      Driver
	shutdown    bool
}

// Creates a new UI context.  This also initializes the UI state.
// Returns the context and an error.
func NewUI() (*Ui, error) {
	driver := &TermboxDriver{}
	err := driver.Init()

	if err != nil {
		return nil, err
	}

	drawContext := &DrawContext{driver: driver}
	ui := &Ui{drawContext: drawContext, driver: driver}

	return ui, nil
}

// Closes the UI context.
func (ui *Ui) Close() {
	ui.driver.Close()
}

// Sets the root component
func (ui *Ui) SetRootComponent(comp UiComponent) {
	ui.rootComponent = comp
	ui.Remeasure()
}

// Sets the focused component
func (ui *Ui) SetFocusedComponent(newFocused FocusableComponent) {
	ui.focusedComponent = newFocused
}

// Remeasures the UI
func (ui *Ui) Remeasure() {
	ui.drawContext.X = 0
	ui.drawContext.Y = 0
	ui.drawContext.W, ui.drawContext.H = ui.driver.Size()

	ui.rootComponent.Remeasure(ui.drawContext.W, ui.drawContext.H)
}

// Redraws the UI.
func (ui *Ui) Redraw() {
	ui.Remeasure()

	ui.rootComponent.Redraw(ui.drawContext)
	ui.driver.Sync()
}

// Quit indicates to the UI that it should shutdown
func (ui *Ui) Shutdown() {
	ui.shutdown = true
}

// Enter the UI loop
func (ui *Ui) Loop() {
	for !ui.shutdown {
		ui.Redraw()
		event := ui.driver.WaitForEvent()

		// TODO: If the event is a key-press, do something.
		if event.Type == EventKeyPress {
			if ui.focusedComponent != nil {
				ui.focusedComponent.KeyPressed(event.Ch, event.Par)
			}
		} else if event.Type == EventResize {

			// HACK: Find another way to refresh the size of the screen to prevent a full redraw.
			ui.driver.Sync()
		}
	}
}