package main

import (
	"encoding/json"
	"fmt"
	"github.com/beevik/guid"
	"github.com/gorilla/websocket"
	"net/http"
	"strings"
	"time"
)

func signalHandler(w http.ResponseWriter, r *http.Request) {
	token := r.FormValue("token")

	if token == "" {
		fmt.Println("signalHandler Error : token is empty")
	}
	wsConn, upgradeErr := upgrader.Upgrade(w, r, w.Header())

	if upgradeErr != nil {
		return
	}

	defer func() {
		if reco := recover(); reco != any(nil) {
			fmt.Printf("Signal Runtime error caught: %v", reco)
		}
	}()

	sessionGuid := guid.New().String()

	fastLinkService.NewSignalSession(token, sessionGuid, wsConn)

	wsConn.WriteMessage(websocket.TextMessage, []byte("0{\"sid\":\""+guid.New().String()+"\",\"upgrades\":[\"websocket\"],\"pingInterval\":25000,\"pingTimeout\":60000}"))
	wsConn.WriteMessage(websocket.TextMessage, []byte("40"))
	wsConn.WriteMessage(websocket.TextMessage, []byte("42[\"server-authenticated\",{\"uid\":\""+token+"\",\"authenticated\":true}]"))

	for {
		wsConn.SetReadDeadline(time.Now().In(TimeLocation).Add(time.Second * 60))
		messageType, p, readError := wsConn.ReadMessage()
		if readError != nil {
			Logger.Println("Signal WebSocket异常断开," + wsConn.RemoteAddr().String() + ",异常信息:" + readError.Error())
			signalSession := fastLinkService.GetSignalSession(token)
			fastLinkService.RemoveSignalSession(token, sessionGuid)
			if signalSession != nil {
				//推送UI提示
				notifyOnlineUserChange(signalSession.RelateDeviceNo)
			}

			wsConn.Close()
			return
		}
		if messageType == websocket.CloseMessage {
			Logger.Println("Signal WebSocket断开," + wsConn.RemoteAddr().String())
			signalSession := fastLinkService.GetSignalSession(token)
			fastLinkService.RemoveSignalSession(token, sessionGuid)
			if signalSession != nil {
				//推送UI提示
				notifyOnlineUserChange(signalSession.RelateDeviceNo)
			}
			wsConn.Close()
			return
		}
		strData := string(p)
		//fmt.Printf("SIGNAL:" + strData + "\n")

		index := strings.Index(strData, "[")
		cmd := ""
		var items []interface{}
		if index != -1 {
			cmd = strData[0:index]
			json.Unmarshal([]byte(strData[index:]), &items)
		} else {
			cmd = strData
		}
		if len(cmd) > 1 && cmd[:2] == "42" {
			cmd = "42"
		}
		switch cmd {
		case "2":
			wsConn.WriteMessage(websocket.TextMessage, []byte("3"))
		case "42":
			if items[0] == "KeepAlive" {
				wsConn.WriteMessage(websocket.TextMessage, []byte("42[\"KeepAliveAck\",{}]"))
			} else if items[0] == "owt-message" {
				from := ""
				if _, ok := items[1].(map[string]interface{})["from"]; ok {
					from = items[1].(map[string]interface{})["from"].(string)
				}
				if from == "" {
					from = token
				}

				to := items[1].(map[string]interface{})["to"].(string)
				data := items[1].(map[string]interface{})["data"].(string)
				target := fastLinkService.GetSignalSession(to)
				if target != nil {
					target.WsConn.WriteMessage(websocket.TextMessage, makeOwtMessage(from, to, data))
				}
			}
		}
	}
}

func makeOwtMessage(from string, to string, data string) []byte {
	var message []interface{}
	message = append(message, "owt-message")
	var m map[string]string
	m = make(map[string]string)
	m["from"] = from
	m["to"] = to
	m["data"] = data
	message = append(message, m)
	marshal, _ := json.Marshal(message)
	return append([]byte("42"), marshal...)
}