package semantices

import (
	"image"
	"image/color"
	"image/png"
	"os"
)

const (
	Width  = 800
	Height = 600
)

var img *image.RGBA

func InitCanvas() {
	img = image.NewRGBA(image.Rect(0, 0, Width, Height))
	white := color.RGBA{255, 255, 255, 255}
	for y := 0; y < Height; y++ {
		for x := 0; x < Width; x++ {
			img.Set(x, y, white)
		}
	}
}

func DrawPixel(x, y int) {
	if img == nil {
		return
	}
	if x < 0 || x >= Width || y < 0 || y >= Height {
		return
	}
	img.Set(x, y, color.Black)
}

func SavePNG(filename string) error {
	if img == nil {
		return nil
	}
	f, err := os.Create(filename)
	if err != nil {
		return err
	}
	defer f.Close()
	return png.Encode(f, img)
}