package pixelflut

import (
	"bufio"
	"encoding/hex"
	"image"
	"image/color"
	"log"
	"net"
	"net/textproto"
	"strconv"
	"strings"
)

// Flut asynchronously sends the given image to pixelflut server at `address`
//   using `conns` connections. Pixels are sent row wise, unless `shuffle` is set.
func Flut(img image.Image, position image.Point, shuffle bool, address string, conns int) {
	cmds := commandsFromImage(img, position)
	if shuffle {
		cmds.Shuffle()
	}

	messages := cmds.Chunk(conns)
	for _, msg := range messages {
		go bombAddress(msg, address)
	}
}

// FetchImage asynchronously uses `conns` to fetch pixels within `bounds` from
//   a pixelflut server at `address`, and writes them into the returned Image.
func FetchImage(bounds image.Rectangle, address string, conns int) (img *image.NRGBA) {
	img = image.NewNRGBA(bounds)
	cmds := cmdsFetchImage(bounds).Chunk(conns)

	for i := 0; i < conns; i++ {
		conn, err := net.Dial("tcp", address)
		if err != nil {
			log.Fatal(err)
		}

		// @cleanup: parsePixels calls conn.Close(), as deferring it here would
		//   instantly close it
		go parsePixels(img, conn)
		go bombConn(cmds[i], conn)
	}

	return img
}

func parsePixels(target *image.NRGBA, conn net.Conn) {
	reader := bufio.NewReader(conn)
	tp := textproto.NewReader(reader)
	defer conn.Close()

	for {
		// @speed: textproto seems not the fastest, buffer text manually & split at \n ?
		res, err := tp.ReadLine()
		if err != nil {
			log.Fatal(err)
		}

		// @speed: Split is ridiculously slow due to mallocs!
		//   chunk last 6 chars off -> color, remove first 3 chars, find space in
		//   remainder, then Atoi() xy?
		res2 := strings.Split(res, " ")
		x, _ := strconv.Atoi(res2[1])
		y, _ := strconv.Atoi(res2[2])
		col, _ := hex.DecodeString(res2[3])

		target.Set(x, y, color.NRGBA{
			uint8(col[0]),
			uint8(col[1]),
			uint8(col[2]),
			255,
		})
	}
}