package top.haijunit.train.websocket;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import jakarta.websocket.*;
import jakarta.websocket.server.PathParam;
import jakarta.websocket.server.ServerEndpoint;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Component;

import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * @author zhanghaijun
 * @date 2023/11/3 16:36
 * @description websocket服务接口
 */
@Component
@ServerEndpoint("/socket/{uid}")
@Slf4j
public class WebSocketServer {

    /**
     * 记录当前在线连接数
     */
    private static int onlineCount = 0;

    /**
     * 使用线程安全的ConcurrentHashMap来存放每个客户端对应的WebSocket对象
     */
    private static final ConcurrentHashMap<String, WebSocketServer> webSocketMap = new ConcurrentHashMap<>();

    /**
     * 与某个客户端的连接会话，需要通过它来给客户端发送数据
     */
    private Session session;

    /**
     * 接收客户端消息的uid
     */
    private String uid = "";

    /**
     * 连接建立成功调用的方法
     * @param session
     * @param uid
     */
    @OnOpen
    public void onOpen(Session session, @PathParam("uid") String uid) {
        this.session = session;
        this.uid = uid;
        if (webSocketMap.containsKey(uid)) {
            webSocketMap.remove(uid);
            //加入到set中
            webSocketMap.put(uid, this);
        } else {
            //加入set中
            webSocketMap.put(uid, this);
            //在线数加1
            addOnlineCount();
        }

        log.info("用户【" + uid + "】连接成功，当前在线人数为:" + getOnlineCount());
        try {
            sendMsg("连接成功");
        } catch (IOException e) {
            log.error("用户【" + uid + "】网络异常!", e);
        }
    }

    /**
     * 连接关闭调用的方法
     */
    @OnClose
    public void onClose() {
        if (webSocketMap.containsKey(uid)) {
            webSocketMap.remove(uid);
            //从set中删除
            subOnlineCount();
        }
        log.info("用户【" + uid + "】退出，当前在线人数为:" + getOnlineCount());
    }

    /**
     * 收到客户端消息后调用的方法
     * @param message 客户端发送过来的消息
     * @param session 会话
     */
    @OnMessage
    public void onMessage(String message, Session session) {
        log.info("用户【" + uid + "】发送报文:" + message);
        //群发消息
        //消息保存到数据库或者redis
        if (StringUtils.isNotBlank(message)) {
            try {
                //解析发送的报文
                ObjectMapper objectMapper = new ObjectMapper();
                Map<String, String> map = objectMapper.readValue(message, new TypeReference<Map<String, String>>(){});
                //追加发送人(防止串改)
                map.put("fromUID", this.uid);
                String toUID = map.get("toUID");
                //传送给对应的toUserId用户的WebSocket
                if (StringUtils.isNotBlank(toUID) && webSocketMap.containsKey(toUID)) {
                    webSocketMap.get(toUID).sendMsg(objectMapper.writeValueAsString(map));
                } else {
                    //若果不在这个服务器上，可以考虑发送到mysql或者redis
                    log.error("请求目标用户【" + toUID + "】不在该服务器上");
                }
            } catch (Exception e) {
                log.error("用户【" + uid + "】发送消息异常！", e);
            }
        }
    }

    /**
     * 处理错误
     * @param session
     * @param error
     */
    @OnError
    public void onError(Session session, Throwable error) {
        log.error("用户【" + this.uid + "】处理消息错误，原因:" + error.getMessage());
        error.printStackTrace();
    }

    /**
     * 实现服务器主动推送
     * @param msg
     * @throws IOException
     */
    private void sendMsg(String msg) throws IOException {
        this.session.getBasicRemote().sendText(msg);
    }

    /**
     * 发送自定义消息
     * @param message
     * @param uid
     * @throws IOException
     */
    public static void sendInfo(String message, @PathParam("uid") String uid) throws IOException {
        log.info("发送消息到用户【" + uid + "】发送的报文:" + message);
        if (!StringUtils.isEmpty(uid) && webSocketMap.containsKey(uid)) {
            webSocketMap.get(uid).sendMsg(message);
        } else {
            log.error("用户【" + uid + "】不在线！");
        }
    }

    private static synchronized int getOnlineCount() {
        return onlineCount;
    }

    private static synchronized void addOnlineCount() {
        WebSocketServer.onlineCount++;
    }

    private static synchronized void subOnlineCount() {
        WebSocketServer.onlineCount--;
    }

}