package engine

import (
	"fmt"
	"image"
	"io/fs"

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

var (
	AssetFS fs.FS

	imageCache = make(map[string]*ebiten.Image)
)

type ImageRef struct {
	Path string

	image *ebiten.Image
}

func (r *ImageRef) Image() (*ebiten.Image, error) {
	if r.image != nil {
		return r.image, nil
	}
	r.image = imageCache[r.Path]
	if r.image != nil {
		return r.image, nil
	}
	f, err := AssetFS.Open(r.Path)
	if err != nil {
		return nil, fmt.Errorf("open asset: %w", err)
	}
	defer f.Close()
	i, _, err := image.Decode(f)
	if err != nil {
		return nil, fmt.Errorf("decode asset: %w", err)
	}
	r.image = ebiten.NewImageFromImage(i)
	imageCache[r.Path] = r.image
	return r.image, nil
}