package logic

//websocket连接
import (
	"bytes"
	"encoding/hex"
	"encoding/json"
	"errors"
	"fmt"
	"fusenapi/constants"
	"fusenapi/utils/auth"
	"fusenapi/utils/basic"
	"fusenapi/utils/encryption_decryption"
	"fusenapi/utils/websocket_data"
	"net/http"
	"strings"
	"sync"
	"time"

	"github.com/google/uuid"
	"github.com/gorilla/websocket"

	"context"

	"fusenapi/server/websocket/internal/svc"

	"github.com/zeromicro/go-zero/core/logx"
)

type DataTransferLogic struct {
	logx.Logger
	ctx    context.Context
	svcCtx *svc.ServiceContext
}

func NewDataTransferLogic(ctx context.Context, svcCtx *svc.ServiceContext) *DataTransferLogic {
	return &DataTransferLogic{
		Logger: logx.WithContext(ctx),
		ctx:    ctx,
		svcCtx: svcCtx,
	}
}

var (
	//临时对象缓存池
	buffPool = sync.Pool{
		New: func() interface{} {
			return bytes.Buffer{}
		},
	}
	//升级websocket
	upgrader = websocket.Upgrader{
		//最大可读取大小 1M
		ReadBufferSize: 1024,
		//最大可写大小 1M
		WriteBufferSize: 1024,
		//握手超时时间15s
		HandshakeTimeout: time.Second * 15,
		//允许跨域
		CheckOrigin: func(r *http.Request) bool {
			return true
		},
		//写的缓冲队列
		WriteBufferPool: &buffPool,
		//是否支持压缩
		EnableCompression: true,
	}
	//websocket连接存储
	mapConnPool = sync.Map{}
	//用户标识的连接(白板用户不存)
	mapUserConnPool = make(map[string]map[string]struct{}) //key是user_id +"_"+guest_id （val是个普通map，存储这个用户的所有连接标识）
	//用户标识的连接增删操作队列
	userConnPoolCtlChan = make(chan userConnPoolCtlChanItem, getCacheChanLenByLevel(4))
	//是否开启debug
	openDebug = true
	//允许跨域的origin
	mapAllowOrigin = map[string]struct{}{
		"https://www.fusen.3718.cn": struct{}{},
		"http://www.fusen.3718.cn":  struct{}{},
	}
)

// 用户标识的连接增删操作队列传输的值的结构
type userConnPoolCtlChanItem struct {
	userId      int64               //必须（两个用户id任意一个不为0）
	guestId     int64               //必须（两个用户id任意一个不为0）
	uniqueId    string              //主连接池唯一标识（添加/删除时候必须）
	message     []byte              //消息（发送消息传的,格式是经过标准输出序列化后的数据）
	messageType constants.Websocket //消息类型（发送消息传的）
	option      int64               //操作 2发消息 1增加 0删除
}

// 每个连接的连接基本属性
type wsConnectItem struct {
	conn                 *websocket.Conn      //websocket的连接(基本属性)
	userAgent            string               //用户代理头信息(基本属性，用于重连标识验证因素之一)
	logic                *DataTransferLogic   //logic(基本属性，用于获取上下文，配置或者操作数据库)
	closeChan            chan struct{}        //ws连接关闭chan(基本属性)
	isClose              bool                 //是否已经关闭(基本属性)
	uniqueId             string               //ws连接唯一标识(基本属性)
	inChan               chan []byte          //接受消息缓冲队列(基本属性)
	outChan              chan []byte          //要发送回客户端的消息缓冲队列(基本属性)
	mutex                sync.Mutex           //互斥锁(基本属性)
	userId               int64                //用户id(基本属性)
	guestId              int64                //游客id(基本属性)
	extendRenderProperty extendRenderProperty //扩展云渲染属性(扩展属性)
}

// 请求建立连接，升级websocket协议
func (l *DataTransferLogic) DataTransfer(w http.ResponseWriter, r *http.Request) {
	origin := r.Header.Get("Origin")
	//判断是不是允许的跨域
	if !openDebug {
		upgrader.CheckOrigin = func(r *http.Request) bool {
			if _, ok := mapAllowOrigin[origin]; !ok {
				return false
			}
			return true
		}
	}
	//把子协议携带的token设置到标准token头信息中
	token := r.Header.Get("Sec-Websocket-Protocol")
	//有token是正常用户，无则是白板用户，也可以连接
	if token != "" {
		r.Header.Set("Authorization", "Bearer "+token)
		//设置Sec-Websocket-Protocol
		upgrader.Subprotocols = []string{token}
	}
	//判断下是否火狐浏览器(获取浏览器第一条消息返回有收不到的bug需要延迟1秒)
	userAgent := r.Header.Get("User-Agent")
	//是否火狐浏览器
	isFirefoxBrowser := false
	if strings.Contains(userAgent, "Firefox") {
		isFirefoxBrowser = true
	}
	//升级websocket
	conn, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		logx.Error("http upgrade websocket err:", err)
		return
	}
	//鉴权不成功后断开
	var (
		userInfo *auth.UserInfo
		isAuth   bool
	)
	isAuth, userInfo = l.checkAuth(r)
	if !isAuth {
		//未授权响应消息
		l.unAuthResponse(conn, isFirefoxBrowser)
		conn.Close()
		return
	}
	//设置连接
	ws, err := l.setConnPool(conn, userInfo, isFirefoxBrowser, userAgent)
	if err != nil {
		conn.Close()
		return
	}
	//循环读客户端信息
	go ws.reciveBrowserMessage()
	//消费出口数据并发送浏览器端
	go ws.consumeOutChanData()
	//消费入口数据
	go ws.consumeInChanData()
	//操作连接中渲染任务的增加/删除
	go ws.operationRenderTask()
	//消费渲染缓冲队列
	go ws.consumeRenderImageData()
	//心跳
	ws.heartbeat()
}

// 设置连接
func (l *DataTransferLogic) setConnPool(conn *websocket.Conn, userInfo *auth.UserInfo, isFirefoxBrowser bool, userAgent string) (wsConnectItem, error) {
	//生成连接唯一标识（失败重试10次）
	uniqueId, err := l.getUniqueId(userInfo, userAgent, 10)
	if err != nil {
		//发送获取唯一标识失败的消息
		l.sendGetUniqueIdErrResponse(conn)
		return wsConnectItem{}, err
	}
	//根据不同用户获取不同缓冲队列长度
	websocketInChanLen, websocketOutChanLen, renderImageTaskCtlChanLen, renderChanLen := getCacheChanLenByUser(userInfo.UserId, userInfo.GuestId)
	ws := wsConnectItem{
		conn:      conn,
		userAgent: userAgent,
		logic:     l,
		closeChan: make(chan struct{}, 1),
		isClose:   false,
		uniqueId:  uniqueId,
		inChan:    make(chan []byte, websocketInChanLen),
		outChan:   make(chan []byte, websocketOutChanLen),
		mutex:     sync.Mutex{},
		userId:    userInfo.UserId,
		guestId:   userInfo.GuestId,
		extendRenderProperty: extendRenderProperty{
			renderImageTask:        make(map[string]*renderTask),
			renderImageTaskCtlChan: make(chan renderImageControlChanItem, renderImageTaskCtlChanLen),
			renderChan:             make(chan []byte, renderChanLen),
		},
	}
	//保存连接
	mapConnPool.Store(uniqueId, ws)
	//非白板用户，需要为这个用户建立map索引便于通过用户查询
	if userInfo.IsUser() || userInfo.IsGuest() {
		createUserConnPoolElement(userInfo.UserId, userInfo.GuestId, uniqueId)
	}
	if isFirefoxBrowser {
		time.Sleep(time.Second * 1) //兼容下火狐(直接发回去收不到第一条消息：有待研究)
	}
	ws.sendToOutChan(ws.respondDataFormat(constants.WEBSOCKET_CONNECT_SUCCESS, uniqueId))
	return ws, nil
}

// 根据level获取缓冲队列长度
func getCacheChanLenByLevel(level int) int {
	switch level {
	case 1:
		return 50
	case 2:
		return 100
	case 3:
		return 500
	case 4:
		return 1000
	default:
		return 50
	}
}

// 根据用户获取缓冲队列长度
func getCacheChanLenByUser(userId, guestId int64) (websocketInChanLen, websocketOutChanLen, renderImageTaskCtlChanLen, renderChanLen int) {
	var l int
	if userId > 0 {
		l = getCacheChanLenByLevel(3)
	} else if guestId > 0 {
		l = getCacheChanLenByLevel(2)
	} else {
		l = getCacheChanLenByLevel(2)
	}
	return l, l, l, l
}

// 添加用户索引池ws连接
func createUserConnPoolElement(userId, guestId int64, uniqueId string) {
	data := userConnPoolCtlChanItem{
		userId:      userId,
		guestId:     guestId,
		uniqueId:    uniqueId,
		message:     nil,
		messageType: "",
		option:      1,
	}
	select {
	case userConnPoolCtlChan <- data:
		return
	case <-time.After(time.Millisecond * 200):
		return
	}
}

// 从用户索引池删除ws连接
func deleteUserConnPoolElement(userId, guestId int64, uniqueId string) {
	data := userConnPoolCtlChanItem{
		userId:      userId,
		guestId:     guestId,
		uniqueId:    uniqueId,
		message:     nil,
		messageType: "",
		option:      0,
	}
	select {
	case userConnPoolCtlChan <- data:
		return
	case <-time.After(time.Millisecond * 200):
		return
	}
}

// 根据用户索引发现链接并发送(广播)消息到出口队列
func sendToOutChanByUserIndex(userId, guestId int64, message []byte) {
	data := userConnPoolCtlChanItem{
		userId:   userId,
		guestId:  guestId,
		uniqueId: "",
		message:  message,
		option:   2,
	}
	select {
	case userConnPoolCtlChan <- data:
		return
	case <-time.After(time.Millisecond * 200):
		return
	}
}

// 消费用户索引创建/删除/发送消息中的任务数据
func ConsumeUserConnPoolCtlChanData(ctx context.Context) {
	defer func() {
		if err := recover(); err != nil {
			logx.Error("ConsumeUserConnPoolCtlChanData panic:", err)
		}
	}()
	go func() {
		select {
		case <-ctx.Done():
			panic("ConsumeUserConnPoolCtlChanData ctx deadline")
		}
	}()
	var (
		data    userConnPoolCtlChanItem
		userKey string
	)
	for {
		select {
		case data = <-userConnPoolCtlChan:
			userKey = getmapUserConnPoolUniqueId(data.userId, data.guestId)
			switch data.option {
			case 2: //发送消息
				logx.Info("通过用户id索引发送消息")
				mapUserUniqueId, ok := mapUserConnPool[userKey]
				if !ok {
					logx.Info("通过用户id索引发送消息,连接不存在，用户索引key:", userKey)
					continue
				}
				for uniqueId, _ := range mapUserUniqueId {
					//根据uniqueId查询原始池中连接
					mapConnPoolVal, ok := mapConnPool.Load(uniqueId)
					if !ok {
						logx.Info("通过用户id索引发送消息,连接不存在，用户索引key:", userKey, "  原始uniqueId:", uniqueId)
						continue
					}
					originConn, ok := mapConnPoolVal.(wsConnectItem)
					if !ok {
						logx.Error("通过用户id索引发送消息,断言原始连接失败，用户索引key:", userKey, "  原始uniqueId:", uniqueId)
						continue
					}
					originConn.sendToOutChan(data.message)
				}
			case 1: //添加
				logx.Info("添加用户id索引标识：", data.uniqueId)
				//存在这个用户的map池子
				if mapUserUniqueId, ok := mapUserConnPool[userKey]; ok {
					mapUserUniqueId[data.uniqueId] = struct{}{}
				} else {
					mapUserConnPool[userKey] = make(map[string]struct{})
					mapUserConnPool[userKey][data.uniqueId] = struct{}{}
				}
			case 0: //删除
				logx.Info("删除用户id索引标识：", data.uniqueId)
				if mapUserUniqueId, ok := mapUserConnPool[userKey]; ok {
					delete(mapUserUniqueId, data.uniqueId)
				}
			}
		}
	}
}

// 获取mapUserConnPool唯一id
func getmapUserConnPoolUniqueId(userId, guestId int64) (uniqueId string) {
	if userId > 0 {
		guestId = 0
	}
	return fmt.Sprintf("%d_%d", userId, guestId)
}

// 获取websocket发送到前端使用的数据传输类型（debug开启是文本，否则是二进制）
func getWebsocketBaseTransferDataFormat() int {
	if openDebug {
		return websocket.TextMessage
	}
	return websocket.BinaryMessage
}

// 获取唯一id
func (l *DataTransferLogic) getUniqueId(userInfo *auth.UserInfo, userAgent string, retryTimes int) (uniqueId string, err error) {
	if retryTimes < 0 {
		return "", errors.New("failed to get unique id")
	}
	//后面拼接上用户id
	uniqueId = hex.EncodeToString([]byte(uuid.New().String())) + getUserJoinPart(userInfo.UserId, userInfo.GuestId, userAgent)
	//存在则从新获取
	if _, ok := mapConnPool.Load(uniqueId); ok {
		uniqueId, err = l.getUniqueId(userInfo, userAgent, retryTimes-1)
		if err != nil {
			return "", err
		}
	}
	//加密
	uniqueId, err = encryption_decryption.CBCEncrypt(uniqueId)
	if err != nil {
		return "", err
	}
	return uniqueId, nil
}

// 鉴权
func (l *DataTransferLogic) checkAuth(r *http.Request) (isAuth bool, userInfo *auth.UserInfo) {
	// 解析JWT token,并对空用户进行判断
	userInfo, err := basic.ParseJwtToken(r, l.svcCtx)
	if err != nil {
		return false, nil
	}
	if userInfo.UserId > 0 {
		userInfo.GuestId = 0
	}
	//白板用户
	return true, userInfo
}

// 鉴权失败通知
func (l *DataTransferLogic) unAuthResponse(conn *websocket.Conn, isFirefoxBrowser bool) {
	rsp := websocket_data.DataTransferData{
		T: constants.WEBSOCKET_UNAUTH,
		D: nil,
	}
	b, _ := json.Marshal(rsp)
	if isFirefoxBrowser {
		time.Sleep(time.Second * 1) //兼容下火狐(直接发回去收不到第一条消息：有待研究)
	}
	//先发一条正常信息
	_ = conn.WriteMessage(getWebsocketBaseTransferDataFormat(), b)
	//发送关闭信息
	_ = conn.WriteMessage(websocket.CloseMessage, nil)
}

// 获取唯一标识失败通知
func (l *DataTransferLogic) sendGetUniqueIdErrResponse(conn *websocket.Conn) {
	time.Sleep(time.Second * 1) //兼容下火狐(直接发回去收不到第一条消息：有待研究)
	rsp := websocket_data.DataTransferData{
		T: constants.WEBSOCKET_CONNECT_ERR,
		D: "err to gen unique id ",
	}
	b, _ := json.Marshal(rsp)
	//先发一条正常信息
	_ = conn.WriteMessage(getWebsocketBaseTransferDataFormat(), b)
	//发送关闭信息
	_ = conn.WriteMessage(websocket.CloseMessage, nil)
}

// 心跳检测
func (w *wsConnectItem) heartbeat() {
	tick := time.Tick(time.Second * 5)
	for {
		select {
		case <-w.closeChan:
			return
		case <-tick:
			//发送心跳信息
			if err := w.conn.WriteMessage(websocket.PongMessage, nil); err != nil {
				logx.Error("发送心跳信息异常，关闭连接:", w.uniqueId, err)
				w.close()
				return
			}
		}
	}
}

// 关闭websocket连接
func (w *wsConnectItem) close() {
	w.mutex.Lock()
	defer w.mutex.Unlock()
	logx.Info("###websocket:", w.uniqueId, "  uid:", w.userId, "  gid:", w.guestId, " is closing....")
	//发送关闭信息
	_ = w.conn.WriteMessage(websocket.CloseMessage, nil)
	w.conn.Close()
	mapConnPool.Delete(w.uniqueId)
	if !w.isClose {
		w.isClose = true
		close(w.closeChan)
		//删除用户级索引
		deleteUserConnPoolElement(w.userId, w.guestId, w.uniqueId)
	}
	logx.Info("###websocket:", w.uniqueId, "  uid:", w.userId, "  gid:", w.guestId, " is closed")
}

// 读取出口缓冲队列数据输出返回给浏览器端
func (w *wsConnectItem) consumeOutChanData() {
	defer func() {
		if err := recover(); err != nil {
			logx.Error("consumeOutChanData panic:", err)
		}
	}()
	for {
		select {
		case <-w.closeChan: //如果关闭了
			return
		case data := <-w.outChan:
			if err := w.conn.WriteMessage(websocket.TextMessage, data); err != nil {
				logx.Error("websocket write loop err:", err)
				w.close()
				return
			}
		}
	}
}

// 消费websocket入口数据池中的数据
func (w *wsConnectItem) consumeInChanData() {
	defer func() {
		if err := recover(); err != nil {
			logx.Error("consumeInChanData:", err)
		}
	}()
	for {
		select {
		case <-w.closeChan:
			return
		case data := <-w.inChan:
			//对不同消息类型分发处理
			w.allocationProcessing(data)
		}
	}
}

// 接受浏览器端发来的消息并写入入口缓冲队列
func (w *wsConnectItem) reciveBrowserMessage() {
	defer func() {
		if err := recover(); err != nil {
			logx.Error("acceptBrowserMessage panic:", err)
		}
	}()
	for {
		select {
		case <-w.closeChan: //如果关闭了
			return
		default: //收取消息
			msgType, data, err := w.conn.ReadMessage()
			if err != nil {
				logx.Error("接受信息错误:", err)
				//关闭连接
				w.close()
				return
			}
			switch msgType {
			case websocket.PingMessage, websocket.PongMessage: //心跳消息(过滤不处理)
				continue
			case websocket.BinaryMessage, websocket.TextMessage: //主要消息
				w.sendToInChan(data)
			case websocket.CloseMessage: //客户端主动关闭消息
				w.close()
			}
		}
	}
}

// 把要传递给客户端的数据放入出口缓冲队列
func (w *wsConnectItem) sendToOutChan(data []byte) {
	select {
	case <-w.closeChan:
		return
	case w.outChan <- data:
		return
	case <-time.After(time.Millisecond * 200): //阻塞超过200ms丢弃
		logx.Error("failed to send to out chan,time expired,data:", string(data))
		return
	}
}

// 发送接受到的消息到入口缓冲队列中
func (w *wsConnectItem) sendToInChan(data []byte) {
	select {
	case <-w.closeChan: //关闭了
		return
	case w.inChan <- data:
		return
	case <-time.After(time.Millisecond * 200): //200豪秒超时丢弃，说明超过消费速度了
		w.sendToOutChan(w.respondDataFormat(constants.WEBSOCKET_INCOME_CACHE_QUEUE_OVERFLOW, "send message is too frequent,the message is ignore by system:"+string(data)))
		return
	}
}

// 格式化为websocket标准返回格式
func (w *wsConnectItem) respondDataFormat(msgType constants.Websocket, data interface{}) []byte {
	d := websocket_data.DataTransferData{
		T: msgType,
		D: data,
	}
	b, _ := json.Marshal(d)
	return b
}

// 处理入口缓冲队列中不同类型的数据（分发处理）
func (w *wsConnectItem) allocationProcessing(data []byte) {
	var parseInfo websocket_data.DataTransferData
	if err := json.Unmarshal(data, &parseInfo); err != nil {
		w.incomeDataFormatErrResponse("invalid format of income message:" + string(data))
		logx.Error("invalid format of websocket message:", err)
		return
	}
	d, _ := json.Marshal(parseInfo.D)
	//获取工厂实例
	processor := w.newAllocationProcessor(parseInfo.T)
	if processor == nil {
		logx.Error("未知消息类型:", string(data))
		return
	}
	//执行工厂方法
	processor.allocationMessage(w, d)
}