package com.example.websocket;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.example.entity.ChatMessage;
import com.example.service.ChatMessageService;
import jakarta.annotation.Resource;
import jakarta.websocket.*;
import jakarta.websocket.server.PathParam;
import jakarta.websocket.server.ServerEndpoint;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

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

@ServerEndpoint("/ws/chat/{userId}/{userType}")
@Component
public class ChatWebSocket {
    
    private static final Logger log = LoggerFactory.getLogger(ChatWebSocket.class);
    
    // 静态变量，用来记录当前在线连接数
    private static int onlineCount = 0;
    
    // 用户ID和WebSocket的映射关系
    private static Map<String, ChatWebSocket> clients = new ConcurrentHashMap<>();
    
    // 与某个客户端的连接会话，用于发送数据
    private Session session;
    
    // 当前连接用户ID
    private Integer userId;
    
    // 当前连接用户类型
    private String userType;
    
    // 注入Service，因为@ServerEndpoint不支持直接注入，需要通过静态变量
    private static ChatMessageService chatMessageService;
    
    private static final ObjectMapper objectMapper = new ObjectMapper();
    
    @Resource
    public void setChatMessageService(ChatMessageService chatMessageService) {
        ChatWebSocket.chatMessageService = chatMessageService;
    }
    
    /**
     * 连接建立成功调用的方法
     */
    @OnOpen
    public void onOpen(Session session, @PathParam("userId") Integer userId, @PathParam("userType") String userType) {
        this.session = session;
        this.userId = userId;
        this.userType = userType;
        
        // 将当前WebSocket对象加入到Map中
        String key = userId + ":" + userType;
        clients.put(key, this);
        
        addOnlineCount();
        log.info("有新连接加入，当前在线人数为：{}", getOnlineCount());
    }
    
    /**
     * 连接关闭调用的方法
     */
    @OnClose
    public void onClose() {
        // 从Map中移除
        String key = userId + ":" + userType;
        clients.remove(key);
        
        subOnlineCount();
        log.info("有一连接关闭，当前在线人数为：{}", getOnlineCount());
    }
    
    /**
     * 收到客户端消息后调用的方法
     */
    @OnMessage
    public void onMessage(String message, Session session) {
        log.info("收到来自用户{}:{}的消息：{}", userId, userType, message);
        
        try {
            // 解析消息
            ChatMessage chatMessage = objectMapper.readValue(message, ChatMessage.class);
            
            // 直接设置发送者信息，不再通过TokenUtils获取
            chatMessage.setSenderId(userId);
            chatMessage.setSenderType(userType);
            chatMessage.setSendTime(new Date());
            chatMessage.setIsRead(false);
            
            // 保存临时ID，用于前端识别消息
            String tempId = null;
            try {
                // 从消息中提取tempId字段
                Map<String, Object> messageMap = objectMapper.readValue(message, Map.class);
                if (messageMap.containsKey("tempId")) {
                    tempId = messageMap.get("tempId").toString();
                }
            } catch (Exception e) {
                log.warn("提取tempId失败", e);
            }
            
            // 保存消息到数据库
            try {
                // 检查发送者和接收者是否有关联关系并保存消息
                chatMessageService.directSaveMessage(chatMessage);
                
                // 将保存后的消息转为Map，以便添加tempId
                Map<String, Object> responseMap = objectMapper.convertValue(chatMessage, Map.class);
                if (tempId != null) {
                    responseMap.put("tempId", tempId);
                }
                String responseJson = objectMapper.writeValueAsString(responseMap);
                
                // 转发消息给接收者
                String receiverKey = chatMessage.getReceiverId() + ":" + chatMessage.getReceiverType();
                ChatWebSocket receiverSocket = clients.get(receiverKey);
                if (receiverSocket != null) {
                    // 接收者在线，发送消息
                    receiverSocket.sendMessage(responseJson);
                }
                
                // 同时也返回给发送者
                sendMessage(responseJson);
            } catch (Exception e) {
                log.error("处理消息时发生错误", e);
                // 发送错误消息给客户端
                ChatMessage errorMessage = new ChatMessage();
                errorMessage.setSenderId(0);
                errorMessage.setSenderType("system");
                errorMessage.setReceiverId(userId);
                errorMessage.setReceiverType(userType);
                errorMessage.setContent("发送消息失败：" + e.getMessage());
                errorMessage.setSendTime(new Date());
                
                // 将错误消息转为Map，以便添加tempId
                Map<String, Object> errorMap = objectMapper.convertValue(errorMessage, Map.class);
                if (tempId != null) {
                    errorMap.put("tempId", tempId);
                }
                sendMessage(objectMapper.writeValueAsString(errorMap));
            }
        } catch (Exception e) {
            log.error("处理消息时发生错误", e);
        }
    }
    
    /**
     * 发生错误时调用
     */
    @OnError
    public void onError(Session session, Throwable error) {
        log.error("发生错误", error);
    }
    
    /**
     * 发送消息
     */
    public void sendMessage(String message) {
        try {
            this.session.getBasicRemote().sendText(message);
        } catch (IOException e) {
            log.error("发送消息失败", e);
        }
    }
    
    /**
     * 服务端主动推送消息
     */
    public static void sendMessage(Integer userId, String userType, String message) {
        String key = userId + ":" + userType;
        ChatWebSocket socket = clients.get(key);
        if (socket != null) {
            socket.sendMessage(message);
        }
    }
    
    public static synchronized int getOnlineCount() {
        return onlineCount;
    }
    
    public static synchronized void addOnlineCount() {
        ChatWebSocket.onlineCount++;
    }
    
    public static synchronized void subOnlineCount() {
        ChatWebSocket.onlineCount--;
    }
}