package network

import (
	"crypto/tls"
	"errors"
	"net"
	"net/http"
	"sync"
	"time"

	"github.com/duanhf2012/origin/v2/log"
	"github.com/gorilla/websocket"
)

type WSServer struct {
	Addr            string
	MaxConnNum      int
	PendingWriteNum int
	MaxReadMsgLen       uint32
	MaxWriteMsgLen      uint32
	CertFile        string
	KeyFile         string
	NewAgent        func(*WSConn) Agent
	ln              net.Listener
	handler         *WSHandler
	messageType     int

	HandshakeTimeout time.Duration
	ReadTimeout      time.Duration
	WriteTimeout     time.Duration
}

type WSHandler struct {
	maxConnNum      int
	pendingWriteNum int
	maxReadMsgLen   uint32
	maxWriteMsgLen  uint32
	newAgent        func(*WSConn) Agent
	upgrader        websocket.Upgrader
	conns           WebsocketConnSet
	mutexConns      sync.Mutex
	wg              sync.WaitGroup
	messageType     int
}

func (handler *WSHandler) SetMessageType(messageType int) {
	handler.messageType = messageType
}

func (handler *WSHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if r.Method != "GET" {
		http.Error(w, "Method not allowed", 405)
		return
	}
	conn, err := handler.upgrader.Upgrade(w, r, nil)
	if err != nil {
		log.Error("upgrade fail", log.String("error", err.Error()))
		return
	}
	conn.SetReadLimit(int64(handler.maxReadMsgLen))
	if handler.messageType == 0 {
		handler.messageType = websocket.TextMessage
	}

	handler.wg.Add(1)
	defer handler.wg.Done()

	handler.mutexConns.Lock()
	if handler.conns == nil {
		handler.mutexConns.Unlock()
		conn.Close()
		return
	}
	if len(handler.conns) >= handler.maxConnNum {
		handler.mutexConns.Unlock()
		conn.Close()
		log.Warn("too many connections")
		return
	}
	handler.conns[conn] = struct{}{}
	handler.mutexConns.Unlock()
	c, ok := conn.NetConn().(*net.TCPConn)
	if !ok {
		tlsConn, ok := conn.NetConn().(*tls.Conn)
		if !ok {
			log.Error("conn error")
			return
		}
		c, ok = tlsConn.NetConn().(*net.TCPConn)
		if !ok {
			log.Error("conn error")
			return
		}
	}

	c.SetLinger(0)
	c.SetNoDelay(true)
	wsConn := newWSConn(conn, r.Header, handler.pendingWriteNum, handler.maxWriteMsgLen, handler.messageType)
	agent := handler.newAgent(wsConn)
	agent.Run()

	// cleanup
	wsConn.Close()
	handler.mutexConns.Lock()
	delete(handler.conns, conn)
	handler.mutexConns.Unlock()
	agent.OnClose()
}

func (server *WSServer) SetMessageType(messageType int) {
	server.messageType = messageType
	if server.handler != nil {
		server.handler.SetMessageType(messageType)
	}
}

func (server *WSServer) Start() error {
	ln, err := net.Listen("tcp", server.Addr)
	if err != nil {
		log.Error("WSServer Listen fail", log.String("error", err.Error()))
		return err
	}
	if server.MaxConnNum <= 0 {
		server.MaxConnNum = 100
		log.Info("invalid MaxConnNum", log.Int("reset", server.MaxConnNum))
	}
	if server.PendingWriteNum <= 0 {
		server.PendingWriteNum = 100
		log.Info("invalid PendingWriteNum", log.Int("reset", server.PendingWriteNum))
	}
	if server.MaxReadMsgLen <= 0 {
		server.MaxReadMsgLen = 4096
		log.Info("invalid MaxReadMsgLen", log.Uint32("reset", server.MaxReadMsgLen))
	}
	if server.HandshakeTimeout <= 0 {
		server.HandshakeTimeout = 15 * time.Second
		log.Info("invalid HandshakeTimeout", log.Duration("reset", server.HandshakeTimeout))
	}
	if server.ReadTimeout <= 0 {
		server.ReadTimeout = 15 * time.Second
		log.Info("invalid ReadTimeout", log.Duration("reset", server.ReadTimeout))
	}
	if server.WriteTimeout <= 0 {
		server.WriteTimeout = 15 * time.Second
		log.Info("invalid WriteTimeout", log.Duration("reset", server.WriteTimeout))
	}

	if server.NewAgent == nil {
		log.Error("NewAgent must not be nil")
		return errors.New("NewAgent must not be nil")
	}

	if server.CertFile != "" || server.KeyFile != "" {
		config := &tls.Config{}
		config.NextProtos = []string{"http/1.1"}

		config.Certificates = make([]tls.Certificate, 1)
		config.Certificates[0], err = tls.LoadX509KeyPair(server.CertFile, server.KeyFile)
		if err != nil {
			log.Error("LoadX509KeyPair fail", log.String("error", err.Error()))
			return err
		}

		ln = tls.NewListener(ln, config)
	}

	server.ln = ln
	server.handler = &WSHandler{
		maxConnNum:      server.MaxConnNum,
		pendingWriteNum: server.PendingWriteNum,
		maxReadMsgLen:   server.MaxReadMsgLen,
		maxWriteMsgLen:  server.MaxWriteMsgLen,
		newAgent:        server.NewAgent,
		conns:           make(WebsocketConnSet),
		messageType:     server.messageType,
		upgrader: websocket.Upgrader{
			HandshakeTimeout: server.HandshakeTimeout,
			CheckOrigin:      func(_ *http.Request) bool { return true },
		},
	}

	httpServer := &http.Server{
		Addr:           server.Addr,
		Handler:        server.handler,
		ReadTimeout:    server.ReadTimeout,
		WriteTimeout:   server.WriteTimeout,
		MaxHeaderBytes: 1024,
	}

	go httpServer.Serve(ln)
	return nil
}

func (server *WSServer) Close() {
	server.ln.Close()

	server.handler.mutexConns.Lock()
	for conn := range server.handler.conns {
		conn.Close()
	}
	server.handler.conns = nil
	server.handler.mutexConns.Unlock()

	server.handler.wg.Wait()
}