package gateway

import (
	"context"
	"fmt"
	"io"
	"net"

	"next-terminal/server/log"
)

type Tunnel struct {
	ID         string // 唯一标识
	LocalHost  string // 本地监听地址
	LocalPort  int    // 本地端口
	RemoteHost string // 远程连接地址
	RemotePort int    // 远程端口
	Gateway    *Gateway
	ctx        context.Context
	cancel     context.CancelFunc
	listener   net.Listener
	err        error
}

func (r *Tunnel) Run() {
	localAddr := fmt.Sprintf("%s:%d", r.LocalHost, r.LocalPort)
	log.Debugf("等待客户端访问 [%v] ...", localAddr)
	localConn, err := r.listener.Accept()
	if err != nil {
		r.err = err
		return
	}

	log.Debugf("客户端 [%v] 已连接至 [%v]", localConn.RemoteAddr().String(), localAddr)
	remoteAddr := fmt.Sprintf("%s:%d", r.RemoteHost, r.RemotePort)
	log.Debugf("连接远程主机 [%v] ...", remoteAddr)
	remoteConn, err := r.Gateway.SshClient.Dial("tcp", remoteAddr)
	if err != nil {
		log.Debugf("连接远程主机 [%v] 失败", remoteAddr)
		r.err = err
		return
	}

	log.Debugf("连接远程主机 [%v] 成功", remoteAddr)
	go copyConn(localConn, remoteConn)
	go copyConn(remoteConn, localConn)
	log.Debugf("开始转发数据 [%v]->[%v]", localAddr, remoteAddr)
	go func() {
		<-r.ctx.Done()
		_ = r.listener.Close()
		_ = localConn.Close()
		_ = remoteConn.Close()
		log.Debugf("SSH隧道 [%v]-[%v] 已关闭", localAddr, remoteAddr)
	}()
}

func (r Tunnel) Close() {
	r.cancel()
}

func copyConn(writer, reader net.Conn) {
	_, _ = io.Copy(writer, reader)
}