package server

import (
	"net/http"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/gorilla/websocket"
	"github.com/qiniu/goc/v2/pkg/log"
)

func (gs *gocServer) serveWatchInternalStream(c *gin.Context) {
	// 检查插桩服务上报的信息
	remoteIP, _ := c.RemoteIP()
	hostname := c.Query("hostname")
	pid := c.Query("pid")
	cmdline := c.Query("cmdline")

	if hostname == "" || pid == "" || cmdline == "" {
		c.JSON(http.StatusBadRequest, gin.H{
			"msg": "missing some params",
		})
		return
	}
	// 计算插桩服务 id
	agentId := gs.generateAgentId(remoteIP.String(), hostname, cmdline, pid)
	// 检查 id 是否重复
	if _, ok := gs.watchAgents.Load(agentId); ok {
		c.JSON(http.StatusBadRequest, gin.H{
			"msg": "the watch agent already exist",
		})
		return
	}
	// upgrade to websocket
	ws, err := gs.upgrader.Upgrade(c.Writer, c.Request, nil)
	if err != nil {
		log.Errorf("fail to establish websocket connection with watch agent: %v", err)
		c.JSON(http.StatusInternalServerError, nil)
	}

	// send close msg and close ws connection
	defer func() {
		gs.watchAgents.Delete(agentId)
		ws.Close()
		log.Infof("close watch connection, %v", hostname)
	}()

	// set pong handler
	ws.SetReadDeadline(time.Now().Add(PongWait))
	ws.SetPongHandler(func(string) error {
		ws.SetReadDeadline(time.Now().Add(PongWait))
		return nil
	})

	// set ping goroutine to ping every PingWait time
	go func() {
		ticker := time.NewTicker(PingWait)
		defer ticker.Stop()

		for range ticker.C {
			if err := gs.wsping(ws, PongWait); err != nil {
				log.Errorf("watch ping to %v failed: %v", hostname, err)
				break
			}
		}
	}()

	log.Infof("one watch agent established, %v, cmdline: %v, pid: %v, hostname: %v", ws.RemoteAddr(), cmdline, pid, hostname)

	for {
		mt, message, err := ws.ReadMessage()
		if err != nil {
			log.Errorf("read from %v: %v", hostname, err)
			break
		}
		if mt == websocket.TextMessage {
			gs.watchCh <- message
		}
	}
}

func (gs *gocServer) watchLoop() {
	for {
		msg := <-gs.watchCh
		gs.watchClients.Range(func(key, value interface{}) bool {
			// 这里是客户端的 ws 连接，不是 agent ws 连接
			gwc := value.(*gocWatchClient)
			err := gwc.ws.WriteMessage(websocket.TextMessage, msg)
			if err != nil {
				gwc.ws.Close()
				gwc.once.Do(func() { close(gwc.exitCh) })
			}

			return true
		})
	}
}