// see https://github.com/defnull/pixelflut

package main

import (
	"bytes"
	"flag"
	"fmt"
	"image"
	"image/color"
	"math/rand"
	"net"
	"os"

	_ "image/gif"
	_ "image/jpeg"
	_ "image/png"
)

const defaultServer = `151.217.15.90:1337` // 37c3

func main() {
	var (
		xoff, yoff, samples int
		shuf                bool
		server              string
	)

	flag.IntVar(&xoff, "xoff", 0, "X-coordinate offset")
	flag.IntVar(&yoff, "yoff", 0, "Y-coordinate offset")
	flag.IntVar(&samples, "samples", 1, "Samples of randomised buffers")
	flag.BoolVar(&shuf, "shuf", false, "Shuffle order of pixels")
	flag.StringVar(&server, "serv", defaultServer, "Server IP and port")
	flag.Parse()
	if flag.NArg() != 1 {
		fmt.Println("This command takes one .png file as an argument")
		os.Exit(1)
	}

	f, err := os.Open(flag.Arg(0))
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	img, _, err := image.Decode(f)
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	var buf bytes.Buffer
	for i := 0; i < samples; i++ {
		var lines []string
		for y := img.Bounds().Min.Y; y <= img.Bounds().Max.Y; y++ {
			for x := img.Bounds().Min.X; x <= img.Bounds().Max.X; x++ {
				rgba := color.RGBAModel.Convert(img.At(x, y)).(color.RGBA)
				var line string
				if rgba.A == 255 {
					line = fmt.Sprintf("PX %d %d %02x%02x%02x\n",
						xoff+x, yoff+y, rgba.R, rgba.G, rgba.B)
				} else if rgba.A > 0 {
					line = fmt.Sprintf("PX %d %d %02x%02x%02x%02x\n",
						xoff+x, yoff+y, rgba.R, rgba.G, rgba.B, rgba.A)
				}
				lines = append(lines, line)
			}
		}
		if shuf {
			rand.Shuffle(len(lines), func(i, j int) {
				lines[i], lines[j] = lines[j], lines[i]
			})
		}
		for l := 0; l < len(lines); l++ {
			fmt.Fprintf(&buf, lines[l])
		}
	}

	conn, err := net.Dial("tcp", server)
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	data := buf.Bytes()
	for {
		conn.Write(data)
	}
}