package main

import (
	"io"
	"log"
	"net"

	"golang.org/x/crypto/ssh"
)

type PortFowarder struct {
	sshCon     *ssh.Client
	localPort  string
	remotePort string
	remoteHost string
}

func NewPortForwarder(sshCon *ssh.Client, localPort, remotePort, remoteHost string) *PortFowarder {
	return &PortFowarder{
		sshCon:     sshCon,
		localPort:  localPort,
		remotePort: remotePort,
		remoteHost: remoteHost,
	}
}

func (pw *PortFowarder) forward() error {
	listener, err := net.Listen("tcp", "127.0.0.1:"+pw.localPort)
	if err != nil {
		log.Printf("Fehler beim Öffnen des lokalen Ports %s: %v", pw.localPort, err)
		return err
	}
	defer listener.Close()

	for {
		localConn, err := listener.Accept()
		if err != nil {
			log.Printf("Fehler beim Akzeptieren der Verbindung: %v", err)
			continue
		}

		remoteConn, err := pw.sshCon.Dial("tcp", pw.remoteHost+":"+pw.remotePort)
		if err != nil {
			log.Printf("Fehler beim Verbinden zum Remote-Host %s:%s: %v", pw.remoteHost, pw.remotePort, err)
			localConn.Close()
			continue
		}

		go pw.copyConn(localConn, remoteConn)
		go pw.copyConn(remoteConn, localConn)
	}
}

func (pw *PortFowarder) copyConn(dst, src net.Conn) {
	defer dst.Close()
	defer src.Close()
	io.Copy(dst, src)
}