package elements

import (
	"github.com/hajimehoshi/ebiten/v2"
)

type Element interface {
	Draw(*ebiten.Image)
	SetAnchor(Point)
	Anchor() Point
	Size() (w, h int)
	Children() []Element
}

type Point struct {
	X, Y int
}

func (p Point) Delta(p2 Point) Point {
	return Point{
		X: p2.X - p.X,
		Y: p2.Y - p.Y,
	}
}

func (p Point) Add(p2 Point) Point {
	return Point{
		X: p.X + p2.X,
		Y: p.Y + p2.Y,
	}
}

type Bounds struct {
	Min           Point
	Width, Height int
}

func (b *Bounds) Contains(p Point) bool {
	return p.X >= b.Min.X && p.X <= b.Min.X+b.Width && p.Y >= b.Min.Y && p.Y <= b.Min.Y+b.Height
}

type Core struct {
	anchor   Point
	children []Element

	name string // For debugging
}

func (c *Core) Anchor() Point {
	return c.anchor
}

func (c *Core) SetAnchor(a Point) {
	d := c.Anchor().Delta(a)
	for _, ch := range c.Children() {
		ch.SetAnchor(ch.Anchor().Add(d))
	}
	c.anchor = a
}

func (c *Core) Children() []Element {
	return c.children
}