package main

import (
	"flag"
	"io"
	"log"
	"net"

	"github.com/armon/go-proxyproto"
	"github.com/facebookgo/flagenv"
)

var (
	target = flag.String("target-host", "127.0.0.1:22", "target TCP host:port")
	port   = flag.String("port", "2222", "TCP port to listen on")
)

func main() {
	flagenv.Parse()
	flag.Parse()

	list, err := net.Listen("tcp", ":"+*port)
	if err != nil {
		panic(err)
	}

	log.Printf("now listening on port %s, forwarding traffic to %s", *port, *target)

	proxyList := &proxyproto.Listener{Listener: list}

	for {
		conn, err := proxyList.Accept()
		if err != nil {
			log.Println(err)
			continue
		}
		go dataTo(conn)
	}
}

func dataTo(conn net.Conn) {
	defer conn.Close()
	peer, err := net.Dial("tcp", *target)
	if err != nil {
		log.Println(*target, err)
	}
	defer peer.Close()

	go io.Copy(conn, peer)
	io.Copy(peer, conn)
}