package main

import (
	"math/rand"
	"image"
	"image/color"
	"image/draw"
	"image/png"
	"os"

	iu "git.nkpl.cc/twocookedfaggots/imageutils"
)

func square(side int) image.Rectangle { return image.Rect(0, 0, side, side) }

func Circles(b image.Rectangle, radius int) chan iu.Circle {
	ch := make(chan iu.Circle)
	go func() {
		defer close(ch)
		for {
			x, y := rand.Int()%b.Dx(), rand.Int()%b.Dy()
			dxdy := b.Dx()*b.Dy()
			r := rand.Int() % (dxdy/(dxdy/radius))
			ch <- iu.Circle{image.Point{x, y}, r}
		}
	}()
	return ch
}

// Converts color.Opaque and color.Transparent to color.Black and color.White respectively.
var BlackAndWhite = color.ModelFunc(
	func(c color.Color) color.Color {
		if color.AlphaModel.Convert(c) == color.Opaque {
			return color.Black
		}
		return color.White
	},
)

func main() {
	canvas := image.NewRGBA(square(1024))
	circles := Circles(canvas.Bounds(), 1024/16)

	// draw n circles
	for i := 0; i < 100; i++ {
		c := <-circles
		draw.DrawMask(
			canvas, canvas.Bounds(), &image.Uniform{color.White}, 
			image.Point{}, c, image.Point{}, draw.Over,
		)
	}
	err := png.Encode(os.Stdout, canvas)
	if err != nil {
		panic(err)
	}
}