package main

import "github.com/nsf/termbox-go"

type Screen interface {
	handleKeyEvent(event termbox.Event) int
	performLayout()
	drawScreen(style Style)
}

type ViewPort struct {
	bytes_per_row  int
	number_of_rows int
	first_row      int
}

const (
	MAIN_SCREEN_INDEX = iota
	ABOUT_SCREEN_INDEX
	EXIT_SCREEN_INDEX
)

func defaultScreens() []Screen {
	//var view_port ViewPort
	main_screen := MainScreen{}
	about_screen := AboutScreen(0)
	screens := [...]Screen{
		&main_screen,
		&about_screen,
	}
	return screens[:]
}

func drawBackground(bg termbox.Attribute) {
	termbox.Clear(0, bg)
}

func layoutAndDrawScreen(screen Screen, style Style) {
	screen.performLayout()
	drawBackground(style.default_bg)
	screen.drawScreen(style)
	termbox.Flush()
}