package protocol

import (
	"bytes"
	"crypto/md5"
	"encoding/hex"
	// "fmt"
	"github.com/TransX/cache"
	"github.com/TransX/log"
	"github.com/TransX/tscipher"
	"net"
	"strconv"
	"sync/atomic"
	"time"
)

var seed int32

func init() {
	seed = 0
}

type Tunnel struct {
	id              string
	src             net.Conn
	dest            net.Conn
	cipherDirection Direction
	regChan         chan interface{}
	unregChan       chan interface{}
}

func NewTunnel(src, dest net.Conn, cipherDirection Direction) *Tunnel {
	return &Tunnel{
		id:              tunnelID(),
		src:             src,
		dest:            dest,
		cipherDirection: cipherDirection,
	}
}

func (this *Tunnel) GetID(id string) string {
	return this.id
}

func (this *Tunnel) SetID(id string) { //rarely used
	this.id = id
}

func (this *Tunnel) SetRegChan(c chan interface{}) {
	this.regChan = c
}

func (this *Tunnel) SetUnRegChan(c chan interface{}) {
	this.unregChan = c
}

//tunnel model : [ -->>server ---- client -->> ](this is a tunnel)
func (this *Tunnel) Run() { //单向的，从src发送到dest
	//进行注册
	this.regChan <- this
	src := this.src
	dest := this.dest
	// cipherDirection := this.cipherDirection
	id := this.id
	// cache := make([]byte, 1024*4) //4kB
	//构建Carrier
	queCache := cache.NewUnblockingQueueCache(1)
	msg := cache.NewBlockingQueueCache(1)
	revCarrier := tscipher.NewCarrier(src, tscipher.NewCipher("XOR"), queCache, msg, id)
	sendCarrier := tscipher.NewCarrier(dest, tscipher.NewCipher("XOR"), queCache, msg, id)
	//timer

	// for {
	// nCh := make(chan int)
	go this.receive(revCarrier)
	go this.send(sendCarrier)
	// log.Info("id %s send %d /receive %d duration %d ms", n, nByte, id, time.Since(srTimer)/1000)
	// }

}

func (this *Tunnel) receive(revCarrier *tscipher.Carrier) {
	src := this.src
	dest := this.dest
	cipherDirection := this.cipherDirection
	id := this.id
	defer func() {
		// log.Debug("tunnel id %s ends", id)
		//注销
		// this.unregChan <- this
		if r := recover(); r != nil {
			if src != nil {
				src.Close()
			}
			if dest != nil {
				dest.Close()
			}
		}
	}()
	// srTimer := time.Now() //send receive timer
	var n int
	var err error
	for {
		rTimer := time.Now() //receive timer
		if cipherDirection != RECEIVE {
			revCarrier.Cipher = nil
			n, err = tscipher.RowReceiveData(revCarrier)
		} else {
			n, err = tscipher.ReceiveData(revCarrier)
		}
		// fmt.Println("receive")
		log.Info("id %s time to receive %d", id, time.Since(rTimer)/1000)
		if err != nil {
			log.Panic("Read panic. Tunnel id: %s. Remote Add: %s Local: %s. Err:%s", id, src.RemoteAddr().String(), src.LocalAddr().String(), err.Error())
		}
		log.Debug("Reived %d bytes (local add %s) from %s. Tunnel: id %s", n, src.LocalAddr().String(),src.RemoteAddr().String(), id)
		// nCh <- n
	}
}

func (this *Tunnel) send(sendCarrier *tscipher.Carrier) {
	src := this.src
	dest := this.dest
	cipherDirection := this.cipherDirection
	id := this.id
	defer func() {
		// log.Debug("tunnel id %s ends", id)
		//注销
		this.unregChan <- this
		if r := recover(); r != nil {
			if src != nil {
				src.Close()
			}
			if dest != nil {
				dest.Close()
			}
		}
	}()
	if cipherDirection != SEND {
		sendCarrier.Cipher = nil
	}
	for {
		// nByte := <-nCh
		// fmt.Println("in send loop\n")
		sTimer := time.Now() //send timer
		_, err := tscipher.SendData(sendCarrier)
		// fmt.Println("send")
		log.Info("id %s time to send %d", id, time.Since(sTimer)/1000)
		if err != nil {
			log.Panic("Write panic. ID: %s, Err: %s, Remote Add: %s", id, err, dest.RemoteAddr().String())
		}
		// log.Debug("Write %d bytes from %s to %s. Tunnel: %s . 18 bytes %x", n, dest.LocalAddr(), dest.RemoteAddr().String(), id, sendCarrier.Cache[:18])
	}
}

func tunnelID() string {
	nowString := time.Now().String() + strconv.Itoa(int(seed))
	atomic.AddInt32(&seed, 1) //避免多线程情况下获得的种子相同
	md5Byte := md5.Sum(bytes.NewBufferString(nowString).Bytes())
	return hex.EncodeToString(md5Byte[:])
}