package pingtunnel

import (
	"github.com/esrrhs/go-engine/src/common"
	"github.com/esrrhs/go-engine/src/loggo"
	"github.com/golang/protobuf/proto"
	"golang.org/x/net/icmp"
	"net"
	"time"
)

func NewServer(key int) (*Server, error) {
	return &Server{
		key: key,
	}, nil
}

type Server struct {
	key int

	conn *icmp.PacketConn

	localConnMap map[string]*ServerConn

	sendPacket     uint64
	recvPacket     uint64
	sendPacketSize uint64
	recvPacketSize uint64

	echoId  int
	echoSeq int
}

type ServerConn struct {
	timeout        int
	ipaddrTarget   *net.UDPAddr
	conn           *net.UDPConn
	tcpaddrTarget  *net.TCPAddr
	tcpconn        *net.TCPConn
	id             string
	activeRecvTime time.Time
	activeSendTime time.Time
	close          bool
	rproto         int
	fm             *FrameMgr
	tcpmode        int
}

func (p *Server) Run() {

	conn, err := icmp.ListenPacket("ip4:icmp", "")
	if err != nil {
		loggo.Error("Error listening for ICMP packets: %s", err.Error())
		return
	}
	p.conn = conn

	p.localConnMap = make(map[string]*ServerConn)

	recv := make(chan *Packet, 10000)
	go recvICMP(*p.conn, recv)

	interval := time.NewTicker(time.Second)
	defer interval.Stop()

	for {
		select {
		case <-interval.C:
			p.checkTimeoutConn()
			p.showNet()
		case r := <-recv:
			p.processPacket(r)
		}
	}
}

func (p *Server) processPacket(packet *Packet) {

	if packet.my.Key != (int32)(p.key) {
		return
	}

	p.echoId = packet.echoId
	p.echoSeq = packet.echoSeq

	if packet.my.Type == (int32)(MyMsg_PING) {
		t := time.Time{}
		t.UnmarshalBinary(packet.my.Data)
		loggo.Info("ping from %s %s %d %d %d", packet.src.String(), t.String(), packet.my.Rproto, packet.echoId, packet.echoSeq)
		sendICMP(packet.echoId, packet.echoSeq, *p.conn, packet.src, "", "", (uint32)(MyMsg_PING), packet.my.Data,
			(int)(packet.my.Rproto), -1, p.key,
			0, 0, 0, 0,
			0)
		return
	}

	loggo.Debug("processPacket %s %s %d", packet.my.Id, packet.src.String(), len(packet.my.Data))

	now := time.Now()

	id := packet.my.Id
	localConn := p.localConnMap[id]
	if localConn == nil {

		if packet.my.Tcpmode > 0 {

			addr := packet.my.Target
			ipaddrTarget, err := net.ResolveTCPAddr("tcp", addr)
			if err != nil {
				loggo.Error("Error ResolveUDPAddr for tcp addr: %s %s", addr, err.Error())
				return
			}

			targetConn, err := net.DialTCP("tcp", nil, ipaddrTarget)
			if err != nil {
				loggo.Error("Error listening for tcp packets: %s", err.Error())
				return
			}

			fm := NewFrameMgr((int)(packet.my.TcpmodeBuffersize), (int)(packet.my.TcpmodeMaxwin), (int)(packet.my.TcpmodeResendTimems))

			localConn = &ServerConn{timeout: (int)(packet.my.Timeout), tcpconn: targetConn, tcpaddrTarget: ipaddrTarget, id: id, activeRecvTime: now, activeSendTime: now, close: false,
				rproto: (int)(packet.my.Rproto), fm: fm, tcpmode: (int)(packet.my.Tcpmode)}

			p.localConnMap[id] = localConn

			go p.RecvTCP(localConn, id, packet.src)

		} else {

			addr := packet.my.Target
			ipaddrTarget, err := net.ResolveUDPAddr("udp", addr)
			if err != nil {
				loggo.Error("Error ResolveUDPAddr for udp addr: %s %s", addr, err.Error())
				return
			}

			targetConn, err := net.DialUDP("udp", nil, ipaddrTarget)
			if err != nil {
				loggo.Error("Error listening for udp packets: %s", err.Error())
				return
			}

			localConn = &ServerConn{timeout: (int)(packet.my.Timeout), conn: targetConn, ipaddrTarget: ipaddrTarget, id: id, activeRecvTime: now, activeSendTime: now, close: false,
				rproto: (int)(packet.my.Rproto), tcpmode: (int)(packet.my.Tcpmode)}

			p.localConnMap[id] = localConn

			go p.Recv(localConn, id, packet.src)
		}
	}

	localConn.activeRecvTime = now

	if packet.my.Type == (int32)(MyMsg_DATA) {

		if packet.my.Tcpmode > 0 {
			f := &Frame{}
			err := proto.Unmarshal(packet.my.Data, f)
			if err != nil {
				loggo.Error("Unmarshal tcp Error %s", err)
				return
			}

			localConn.fm.OnRecvFrame(f)

		} else {
			_, err := localConn.conn.Write(packet.my.Data)
			if err != nil {
				loggo.Info("WriteToUDP Error %s", err)
				localConn.close = true
				return
			}
		}

		p.recvPacket++
		p.recvPacketSize += (uint64)(len(packet.my.Data))
	}
}

func (p *Server) RecvTCP(conn *ServerConn, id string, src *net.IPAddr) {

	loggo.Info("server waiting target response %s -> %s %s", conn.tcpaddrTarget.String(), conn.id, conn.tcpconn.LocalAddr().String())

	loggo.Info("start wait remote connect tcp %s %s", conn.id, conn.tcpaddrTarget.String())
	startConnectTime := time.Now()
	for {
		if conn.fm.IsConnected() {
			break
		}
		conn.fm.Update()
		sendlist := conn.fm.getSendList()
		for e := sendlist.Front(); e != nil; e = e.Next() {
			f := e.Value.(*Frame)
			mb, _ := proto.Marshal(f)
			sendICMP(p.echoId, p.echoSeq, *p.conn, src, "", id, (uint32)(MyMsg_DATA), mb,
				conn.rproto, -1, p.key,
				0, 0, 0, 0,
				0)
			p.sendPacket++
			p.sendPacketSize += (uint64)(len(mb))
		}
		time.Sleep(time.Millisecond * 10)
		now := time.Now()
		diffclose := now.Sub(startConnectTime)
		if diffclose > time.Second*(time.Duration(conn.timeout)) {
			loggo.Info("can not connect remote tcp %s %s", conn.id, conn.tcpaddrTarget.String())
			p.Close(conn)
			return
		}
	}

	loggo.Info("remote connected tcp %s %s", conn.id, conn.tcpaddrTarget.String())

	bytes := make([]byte, 10240)

	tcpActiveRecvTime := time.Now()
	tcpActiveSendTime := time.Now()

	for {
		now := time.Now()
		sleep := true

		left := common.MinOfInt(conn.fm.GetSendBufferLeft(), len(bytes))
		if left > 0 {
			conn.tcpconn.SetReadDeadline(time.Now().Add(time.Millisecond * 1))
			n, err := conn.tcpconn.Read(bytes[0:left])
			if err != nil {
				nerr, ok := err.(net.Error)
				if !ok || !nerr.Timeout() {
					loggo.Info("Error read tcp %s %s %s", conn.id, conn.tcpaddrTarget.String(), err)
					conn.fm.Close()
					break
				}
			}
			if n > 0 {
				sleep = false
				conn.fm.WriteSendBuffer(bytes[:n])
				tcpActiveRecvTime = now
			}
		}

		conn.fm.Update()

		sendlist := conn.fm.getSendList()
		if sendlist.Len() > 0 {
			sleep = false
			conn.activeSendTime = now
			for e := sendlist.Front(); e != nil; e = e.Next() {
				f := e.Value.(*Frame)
				mb, err := proto.Marshal(f)
				if err != nil {
					loggo.Error("Error tcp Marshal %s %s %s", conn.id, conn.tcpaddrTarget.String(), err)
					continue
				}
				sendICMP(p.echoId, p.echoSeq, *p.conn, src, "", id, (uint32)(MyMsg_DATA), mb,
					conn.rproto, -1, p.key,
					0, 0, 0, 0,
					0)
				p.sendPacket++
				p.sendPacketSize += (uint64)(len(mb))
			}
		}

		if conn.fm.GetRecvBufferSize() > 0 {
			sleep = false
			rr := conn.fm.GetRecvReadLineBuffer()
			conn.tcpconn.SetWriteDeadline(time.Now().Add(time.Millisecond * 1))
			n, err := conn.tcpconn.Write(rr)
			if err != nil {
				nerr, ok := err.(net.Error)
				if !ok || !nerr.Timeout() {
					loggo.Info("Error write tcp %s %s %s", conn.id, conn.tcpaddrTarget.String(), err)
					conn.fm.Close()
					break
				}
			}
			if n > 0 {
				conn.fm.SkipRecvBuffer(n)
				tcpActiveSendTime = now
			}
		}

		if sleep {
			time.Sleep(time.Millisecond * 10)
		}

		diffrecv := now.Sub(conn.activeRecvTime)
		diffsend := now.Sub(conn.activeSendTime)
		tcpdiffrecv := now.Sub(tcpActiveRecvTime)
		tcpdiffsend := now.Sub(tcpActiveSendTime)
		if diffrecv > time.Second*(time.Duration(conn.timeout)) || diffsend > time.Second*(time.Duration(conn.timeout)) ||
			tcpdiffrecv > time.Second*(time.Duration(conn.timeout)) || tcpdiffsend > time.Second*(time.Duration(conn.timeout)) {
			loggo.Info("close inactive conn %s %s", conn.id, conn.tcpaddrTarget.String())
			conn.fm.Close()
			break
		}

		if conn.fm.IsRemoteClosed() {
			loggo.Info("closed by remote conn %s %s", conn.id, conn.tcpaddrTarget.String())
			conn.fm.Close()
			break
		}
	}

	startCloseTime := time.Now()
	for {
		now := time.Now()

		conn.fm.Update()

		sendlist := conn.fm.getSendList()
		for e := sendlist.Front(); e != nil; e = e.Next() {
			f := e.Value.(*Frame)
			mb, _ := proto.Marshal(f)
			sendICMP(p.echoId, p.echoSeq, *p.conn, src, "", id, (uint32)(MyMsg_DATA), mb,
				conn.rproto, -1, p.key,
				0, 0, 0, 0,
				0)
			p.sendPacket++
			p.sendPacketSize += (uint64)(len(mb))
		}

		nodatarecv := true
		if conn.fm.GetRecvBufferSize() > 0 {
			rr := conn.fm.GetRecvReadLineBuffer()
			conn.tcpconn.SetWriteDeadline(time.Now().Add(time.Millisecond * 100))
			n, _ := conn.tcpconn.Write(rr)
			if n > 0 {
				conn.fm.SkipRecvBuffer(n)
				nodatarecv = false
			}
		}

		diffclose := now.Sub(startCloseTime)
		timeout := diffclose > time.Second*(time.Duration(conn.timeout))
		remoteclosed := conn.fm.IsRemoteClosed()

		if timeout {
			loggo.Info("close conn had timeout %s %s", conn.id, conn.tcpaddrTarget.String())
			break
		}

		if remoteclosed && nodatarecv {
			loggo.Info("remote conn had closed %s %s", conn.id, conn.tcpaddrTarget.String())
			break
		}

		time.Sleep(time.Millisecond * 100)
	}

	time.Sleep(time.Second)

	loggo.Info("close tcp conn %s %s", conn.id, conn.tcpaddrTarget.String())
	p.Close(conn)
}

func (p *Server) Recv(conn *ServerConn, id string, src *net.IPAddr) {

	loggo.Info("server waiting target response %s -> %s %s", conn.ipaddrTarget.String(), conn.id, conn.conn.LocalAddr().String())

	for {
		bytes := make([]byte, 2000)

		conn.conn.SetReadDeadline(time.Now().Add(time.Millisecond * 100))
		n, _, err := conn.conn.ReadFromUDP(bytes)
		if err != nil {
			nerr, ok := err.(net.Error)
			if !ok || !nerr.Timeout() {
				loggo.Info("ReadFromUDP Error read udp %s", err)
				conn.close = true
				return
			}
		}

		now := time.Now()
		conn.activeSendTime = now

		sendICMP(p.echoId, p.echoSeq, *p.conn, src, "", id, (uint32)(MyMsg_DATA), bytes[:n],
			conn.rproto, -1, p.key,
			0, 0, 0, 0,
			0)

		p.sendPacket++
		p.sendPacketSize += (uint64)(n)
	}
}

func (p *Server) Close(conn *ServerConn) {
	if p.localConnMap[conn.id] != nil {
		if conn.conn != nil {
			conn.conn.Close()
		}
		if conn.tcpconn != nil {
			conn.tcpconn.Close()
		}
		delete(p.localConnMap, conn.id)
	}
}

func (p *Server) checkTimeoutConn() {

	now := time.Now()
	for _, conn := range p.localConnMap {
		if conn.tcpmode > 0 {
			continue
		}
		diffrecv := now.Sub(conn.activeRecvTime)
		diffsend := now.Sub(conn.activeSendTime)
		if diffrecv > time.Second*(time.Duration(conn.timeout)) || diffsend > time.Second*(time.Duration(conn.timeout)) {
			conn.close = true
		}
	}

	for id, conn := range p.localConnMap {
		if conn.tcpmode > 0 {
			continue
		}
		if conn.close {
			loggo.Info("close inactive conn %s %s", id, conn.ipaddrTarget.String())
			p.Close(conn)
		}
	}
}

func (p *Server) showNet() {
	loggo.Info("send %dPacket/s %dKB/s recv %dPacket/s %dKB/s",
		p.sendPacket, p.sendPacketSize/1024, p.recvPacket, p.recvPacketSize/1024)
	p.sendPacket = 0
	p.recvPacket = 0
	p.sendPacketSize = 0
	p.recvPacketSize = 0
}