package com.zzx.coursesystem.util;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicInteger;

import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;

import org.springframework.stereotype.Component;

import com.zzx.coursesystem.model.entity.mongo.LogEntity;

/**
 * @author zhangzhenxin <zhangzhenxin@kuaishou.com>
 * Created on 2021-03-12
 */

@ServerEndpoint(value = "/web/socket/user/{sid}")
@Component
public class WebSocketUserUtils {
    //静态变量，用来记录当前在线连接数。应该把它设计成线程安全的。
    private static AtomicInteger onlineNum = new AtomicInteger();

    //concurrent包的线程安全Set，用来存放每个客户端对应的WebSocketServer对象。
    private static ConcurrentHashMap<String, Session> sessionPools = new ConcurrentHashMap<>();

    //发送消息
    public void sendMessage(Session session, String message) throws IOException {
        if(session != null){
            synchronized (session) {
//                System.out.println("发送数据：" + message);
                session.getBasicRemote().sendText(message);
            }
        }
    }
    //给指定用户发送信息
    public void sendInfo(String userName, String message){
        Session session = sessionPools.get(userName);
        try {
            sendMessage(session, message);
        }catch (Exception e){
            e.printStackTrace();
        }
    }
    //建立连接成功调用
    @OnOpen
    public void onOpen(Session session, @PathParam(value = "sid") String userName){
        sessionPools.put(userName, session);
        addOnlineCount();
        System.out.println(userName + "进入页面！当前人数为" + onlineNum);
    }

    //关闭连接时调用
    @OnClose
    public void onClose(@PathParam(value = "sid") String userName){
        sessionPools.remove(userName);
        subOnlineCount();
        System.out.println(userName + "断开连接！当前人数为" + onlineNum);
    }

    //收到客户端信息
    @OnMessage
    public void onMessage(String message) throws IOException{
        message = "客户端：" + message + ",已收到";
        System.out.println(message);
        for (Session session: sessionPools.values()) {
            try {
                sendMessage(session, message);
            } catch(Exception e){
                e.printStackTrace();
                continue;
            }
        }
    }

    //错误时调用
    @OnError
    public void onError(Session session, Throwable throwable){
        System.out.println("发生错误");
        throwable.printStackTrace();
    }

    public void sendAllInfo(String message){
        for (Session value : sessionPools.values()) {
            try {
                sendMessage(value, message);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public static void addOnlineCount(){
        onlineNum.incrementAndGet();
    }

    public static void subOnlineCount() {
        onlineNum.decrementAndGet();
    }

    public static Map getCurUsers(){
        Enumeration<String> keys = sessionPools.keys();
        Map<Object, Object> result = new HashMap<>();
        result.put("total", onlineNum.get());
        List<LogEntity> userNames = new ArrayList<>();
        while (keys.hasMoreElements()) {
            String userName = keys.nextElement();
            LogEntity logEntity = new LogEntity();
            logEntity.setUserName(userName);
            userNames.add(logEntity);
        }
        result.put("users", userNames);
        return result;
    }
}
