package logic

//websocket连接
import (
	"bytes"
	"encoding/json"
	"fusenapi/constants"
	"fusenapi/utils/auth"
	"fusenapi/utils/id_generator"
	"fusenapi/utils/websocket_data"
	"net/http"
	"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 (
	//全局websocketid生成器
	websocketIdGenerator = id_generator.NewWebsocketId(1)
	//临时缓存对象池
	buffPool = sync.Pool{
		New: func() interface{} {
			return bytes.Buffer{}
		},
	}
	//升级websocket
	upgrader = websocket.Upgrader{
		//最大可读取大小 10M
		ReadBufferSize: 1024 * 10,
		//握手超时时间15s
		HandshakeTimeout: time.Second * 15,
		//允许跨域
		CheckOrigin: func(r *http.Request) bool {
			return true
		},
		//写的缓存池
		WriteBufferPool: &buffPool,
		//是否支持压缩
		EnableCompression: true,
	}
	//websocket连接存储
	mapConnPool = sync.Map{}
	//公共互斥锁
	publicMutex sync.Mutex
)

// 每个连接的连接基本属性
type wsConnectItem struct {
	conn           *websocket.Conn    //websocket的连接
	logic          *DataTransferLogic //logic
	closeChan      chan struct{}      //ws连接关闭chan
	isClose        bool               //是否已经关闭
	uniqueId       string             //ws连接唯一标识
	inChan         chan []byte        //接受消息缓冲通道
	outChan        chan []byte        //发送回客户端的消息
	mutex          sync.Mutex         //互斥锁
	userId         int64              //用户id
	guestId        int64              //游客id
	renderProperty renderProperty     //扩展云渲染属性
}

// 请求建立连接，升级websocket协议
func (l *DataTransferLogic) DataTransfer(w http.ResponseWriter, r *http.Request) {
	//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")
	r.Header.Set("Authorization", "Bearer "+token)
	//设置Sec-Websocket-Protocol
	upgrader.Subprotocols = []string{token}
	//升级websocket
	conn, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		logx.Error("http upgrade websocket err:", err)
		return
	}
	defer conn.Close()
	//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)
		return
	}
	//设置连接
	ws := l.setConnPool(conn, *userInfo)
	defer ws.close()
	//循环读客户端信息
	go ws.readLoop()
	//循环把数据发送给客户端
	go ws.writeLoop()
	//推消息到云渲染
	go ws.sendLoop()
	//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.renderImage()
	//心跳
	ws.heartbeat()
}

// 设置连接
func (l *DataTransferLogic) setConnPool(conn *websocket.Conn, userInfo auth.UserInfo) wsConnectItem {
	publicMutex.Lock()
	defer publicMutex.Unlock()
	//生成连接唯一标识
	uniqueId := l.getUniqueId(userInfo)
	ws := wsConnectItem{
		conn:      conn,
		logic:     l,
		uniqueId:  uniqueId,
		closeChan: make(chan struct{}, 1),
		inChan:    make(chan []byte, 1000),
		outChan:   make(chan []byte, 1000),
		userId:    userInfo.UserId,
		guestId:   userInfo.GuestId,
		renderProperty: renderProperty{
			renderImageTask:        make(map[string]*renderTask),
			renderImageTaskCtlChan: make(chan renderImageControlChanItem, 500),
			renderChan:             make(chan []byte, 500),
		},
	}
	//保存连接
	mapConnPool.Store(uniqueId, ws)
	go func() {
		defer func() {
			if err := recover(); err != nil {
				logx.Error("set conn pool panic:", err)
			}
		}()
		//把连接成功消息发回去
		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
}

// 获取唯一id
func (l *DataTransferLogic) getUniqueId(userInfo auth.UserInfo) string {
	//后面拼接上用户id
	uniqueId := uuid.New().String() + getUserJoinPart(userInfo.UserId, userInfo.GuestId)
	if _, ok := mapConnPool.Load(uniqueId); ok {
		uniqueId = l.getUniqueId(userInfo)
	}
	return uniqueId
}

// 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
	claims, err := l.svcCtx.ParseJwtToken(r)
	// 如果解析JWT token出错,则返回未授权的JSON响应并记录错误消息
	if err != nil {
		logx.Error(err)
		return false, nil
	}
	if claims != nil {
		// 从token中获取对应的用户信息
		userInfo, err = auth.GetUserInfoFormMapClaims(claims)
		// 如果获取用户信息出错,则返回未授权的JSON响应并记录错误消息
		if err != nil {
			logx.Error(err)
			return false, nil
		}
		//不是登录用户也不是游客
		if !userInfo.IsUser() && !userInfo.IsGuest() {
			return false, nil
		}
		return true, userInfo
	}
	return false, nil
}

// 鉴权失败通知
func (l *DataTransferLogic) unAuthResponse(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_UNAUTH,
		D: nil,
	}
	b, _ := json.Marshal(rsp)
	//先发一条正常信息
	_ = conn.WriteMessage(websocket.TextMessage, b)
	//发送关闭信息
	_ = conn.WriteMessage(websocket.CloseMessage, nil)
	//关闭连接
	conn.Close()
}

// 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, " 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)
	}
	logx.Info("websocket:", w.uniqueId, " is closed")
}

// 读取出口缓冲池数据输出返回给浏览器端
func (w *wsConnectItem) writeLoop() {
	defer func() {
		if err := recover(); err != nil {
			logx.Error("write loop 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
			}
		}
	}
}

// 接受客户端发来的消息并写入入口缓冲池
func (w *wsConnectItem) readLoop() {
	defer func() {
		if err := recover(); err != nil {
			logx.Error("read loop panic:", err)
		}
	}()
	for {
		select {
		case <-w.closeChan: //如果关闭了
			return
		default:
			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
			}
			//ping的消息不处理
			if msgType != websocket.PingMessage {
				//消息传入缓冲通道
				w.inChan <- data
			}
		}
	}
}

// 消费websocket入口数据池中的数据
func (w *wsConnectItem) sendLoop() {
	defer func() {
		if err := recover(); err != nil {
			logx.Error("send loop panic:", err)
		}
	}()
	for {
		select {
		case <-w.closeChan:
			return
		case data := <-w.inChan:
			w.dealwithReciveData(data)
		}
	}
}

// 把要传递给客户端的数据放入出口缓冲池
func (w *wsConnectItem) sendToOutChan(data []byte) {
	select {
	case <-w.closeChan:
		return
	case w.outChan <- data:
		return
	case <-time.After(time.Second * 3): //阻塞超过3秒丢弃
		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
}

// 处理入口缓冲池中不同类型的数据（分发处理）
func (w *wsConnectItem) dealwithReciveData(data []byte) {
	var parseInfo websocket_data.DataTransferData
	if err := json.Unmarshal(data, &parseInfo); err != nil {
		logx.Error("invalid format of websocket message:", err)
		w.sendToOutChan(w.respondDataFormat(constants.WEBSOCKET_ERR_DATA_FORMAT, "invalid format of websocket message:"+string(data)))
		return
	}
	d, _ := json.Marshal(parseInfo.D)
	//分消息类型给到不同逻辑处理，可扩展
	switch parseInfo.T {
	//图片渲染
	case constants.WEBSOCKET_RENDER_IMAGE:
		w.sendToRenderChan(d)
	//刷新重连请求恢复上次连接的标识
	case constants.WEBSOCKET_REQUEST_REUSE_LAST_CONNECT:
		w.reuseLastConnect(d)
	default:
		logx.Error("未知消息类型：", parseInfo.T)
	}
}