package com.ard.sample.component.websocket.handler;

import com.alibaba.fastjson2.JSON;
import com.ard.sample.common.model.ResponseResult;
import com.ard.sample.component.websocket.enums.MessageType;
import com.ard.sample.component.websocket.model.Payload;
import com.ard.sample.component.websocket.model.WebSocketMessage;
import com.ard.sample.manage.service.IControlService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.TextWebSocketHandler;

import java.io.IOException;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

@Slf4j
@Component
public class DockWebSocketHandler extends TextWebSocketHandler {

    @Autowired
    private LiveStreamHandler _liveStreamService;

    @Autowired
    private IControlService _controlService;

    // ====================== 心跳相关常量 ======================
    /** 心跳间隔（秒）：客户端需每隔此时间发一次ping */
    private static final long HEARTBEAT_INTERVAL = 30;
    /** 心跳超时阈值（秒）：超过此时间没收到ping，判定连接失效 */
    private static final long HEARTBEAT_TIMEOUT = 90;
    /** 心跳检测任务间隔（秒）：定时检查超时连接 */
    private static final long CHECK_INTERVAL = 10;

    // ====================== 核心存储 ======================
    // 存储用户会话：userId -> WebSocketSession
    private final Map<String, WebSocketSession> userSessions = new ConcurrentHashMap<>();
    // 订阅关系：key=订阅标识(sn+type)，value=订阅用户ID集合
    private final Map<String, Set<String>> subscriptions = new ConcurrentHashMap<>();
    // 关键：为每个WebSocketSession分配独立的锁对象，确保写操作同步
    private final Map<WebSocketSession, Object> sessionLocks = new ConcurrentHashMap<>();
    // 存储用户最后心跳时间：userId -> 最后心跳时间戳（毫秒）
    private final Map<String, Long> userLastHeartbeatTime = new ConcurrentHashMap<>();

    // ====================== 线程池 ======================
    // 延时任务线程池（单线程，守护线程），用于处理连接关闭后的延时清理
    private final ScheduledExecutorService delayExecutor = Executors.newSingleThreadScheduledExecutor(runnable -> {
        Thread thread = new Thread(runnable, "websocket-关闭-延迟-线程");
        thread.setDaemon(true); // 设为守护线程，不阻塞JVM退出
        return thread;
    });

    // 心跳检测线程池（单线程，守护线程），定时检查超时连接
    private final ScheduledExecutorService heartbeatCheckExecutor = Executors.newSingleThreadScheduledExecutor(runnable -> {
        Thread thread = new Thread(runnable, "websocket-心跳检测-线程");
        thread.setDaemon(true);
        return thread;
    });

    // ====================== 初始化心跳检测任务 ======================
    public DockWebSocketHandler() {
        // 项目启动后，每隔 CHECK_INTERVAL 秒执行一次心跳检测
        heartbeatCheckExecutor.scheduleAtFixedRate(this::checkHeartbeatTimeout,
                CHECK_INTERVAL, CHECK_INTERVAL, TimeUnit.SECONDS);
    }

    /**
     * 连接建立后回调
     */
    @Override
    public void afterConnectionEstablished(WebSocketSession session) throws Exception {
        // 从会话属性中获取认证后的用户ID
        String userId = (String) session.getAttributes().get("userId");
        if (userId == null) {
            session.close(CloseStatus.POLICY_VIOLATION.withReason("未认证"));
            return;
        }

        userSessions.put(userId, session);
        // 为新会话初始化锁对象
        sessionLocks.put(session, new Object());
        // 初始化用户最后心跳时间（连接建立即视为一次心跳）
        userLastHeartbeatTime.put(userId, System.currentTimeMillis());

        log.info("用户[{}]已连接，当前在线人数：{}", userId, userSessions.size());
    }

    /**
     * 处理客户端发送的消息（包含心跳消息）
     */
    @Override
    protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
        String userId = (String) session.getAttributes().get("userId");
        String jsonMessage = message.getPayload();

        try {
            // 解析客户端消息
            WebSocketMessage webSocketMessage = JSON.parseObject(jsonMessage, WebSocketMessage.class);
            String type = webSocketMessage.getType();
            Payload payload = webSocketMessage.getPayload();

            // ====================== 处理心跳消息 ======================
            if (MessageType.PING.getType().equals(type)) {
                // 1. 更新用户最后心跳时间
                userLastHeartbeatTime.put(userId, System.currentTimeMillis());
                // 2. 回复pong消息
                WebSocketMessage pongMessage = new WebSocketMessage();
                pongMessage.setType(MessageType.PONG.getType());
                pongMessage.setPayload(new Payload()); // 空payload即可
                sendMessage(session, JSON.toJSONString(pongMessage));
                log.debug("用户[{}]心跳检测成功，已回复pong", userId);
                System.out.println("用户["+userId+"]心跳检测成功，已回复pong");
                return; // 心跳消息无需走后续订阅逻辑
            }

            // 验证消息类型是否合法
            if (!MessageType.fromString(type)) {
                sendMessage(session, "不支持的消息类型：" + type);
                return;
            }

            // 处理订阅/取消订阅
            handleSubscription(userId, type, payload);

        } catch (Exception e) {
            log.error("用户[{}]消息处理错误", userId, e);
            sendMessage(session, "消息格式错误");
        }
    }

    /**
     * 处理订阅/取消订阅逻辑
     */
    private void handleSubscription(String userId, String type, Payload payload) {
        String sn = payload.getSn();
        boolean subscribe = payload.isSubscribe();
        String subscriptionKey = getSubscriptionKey(sn, type); // 生成唯一订阅标识

        if (subscribe) {
            // 订阅操作
            subscriptions.computeIfAbsent(subscriptionKey, k -> ConcurrentHashMap.newKeySet()).add(userId);
            log.info("用户[{}]订阅了 设备[{}]的[{}]类型消息", userId, sn, type);
            if (MessageType.LIVESTREAM.getType().equals(type)) {
                // 开启直播
                log.info("开启设备[{}]直播", sn);
                _liveStreamService.StartLiveStreaming(sn);
            }
        } else {
            // 取消订阅操作
            if (subscriptions.containsKey(subscriptionKey)) {
                subscriptions.get(subscriptionKey).remove(userId);
                if (subscriptions.get(subscriptionKey).isEmpty()) {
                    subscriptions.remove(subscriptionKey);
                    // 若取消的是直播订阅且无其他订阅者，停止直播
                    if (MessageType.LIVESTREAM.getType().equals(type)) {
                        log.info("设备[{}]无订阅者，停止直播", sn);
                        _liveStreamService.StopLiveStreaming(sn);
                    }
                }
                log.info("用户[{}]取消订阅了 设备[{}]的[{}]类型消息", userId, sn, type);
            }
        }
    }

    /**
     * 连接关闭后回调
     */
    @Override
    public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception {
        String userId = (String) session.getAttributes().get("userId");
        if (userId != null) {
            log.info("用户[{}]连接关闭（状态码：{}），将延时5秒执行清理操作", userId, status.getCode());

            // 延时5秒执行清理逻辑
            delayExecutor.schedule(() -> {
                try {
                    // 清理核心存储
                    userSessions.remove(userId);
                    sessionLocks.remove(session);
                    userLastHeartbeatTime.remove(userId); // 清理心跳时间

                    // 清除该用户的所有订阅
                    removeUserAllSubscriptions(userId);

                    log.info("用户[{}]延时5秒清理完成，当前在线人数：{}", userId, userSessions.size());
                } catch (Exception e) {
                    log.error("用户[{}]延时清理操作异常", userId, e);
                }
            }, 5, TimeUnit.SECONDS); // 延时5秒执行
        } else {
            // 无认证用户，直接清理
            sessionLocks.remove(session);
            log.info("无认证用户连接关闭，直接清理会话锁");
        }
    }

    /**
     * 心跳超时检测：断开超过HEARTBEAT_TIMEOUT未发心跳的用户
     */
    private void checkHeartbeatTimeout() {
        long currentTime = System.currentTimeMillis();
        // 遍历所有在线用户，检查心跳超时
        for (Map.Entry<String, Long> entry : userLastHeartbeatTime.entrySet()) {
            String userId = entry.getKey();
            Long lastHeartbeat = entry.getValue();
            WebSocketSession session = userSessions.get(userId);

            // 1. 计算超时时间差
            long timeoutDiff = currentTime - lastHeartbeat;
            if (timeoutDiff > HEARTBEAT_TIMEOUT * 1000) {
                log.warn("用户[{}]心跳超时（{}秒未发ping），将断开连接", userId, timeoutDiff / 1000);
                try {
                    // 2. 主动关闭连接
                    if (session != null && session.isOpen()) {
                        session.close(CloseStatus.SESSION_NOT_RELIABLE.withReason("心跳超时"));
                    }
                } catch (IOException e) {
                    log.error("关闭用户[{}]超时连接失败", userId, e);
                } finally {
                    // 3. 清理该用户的所有数据
                    userSessions.remove(userId);
                    sessionLocks.remove(session);
                    userLastHeartbeatTime.remove(userId);
                    removeUserAllSubscriptions(userId);
                }
            }
        }
    }

    /**
     * 清除用户的所有订阅
     */
    private void removeUserAllSubscriptions(String userId) {
        // 遍历所有订阅，移除该用户并检查是否需要停止直播
        Iterator<Map.Entry<String, Set<String>>> iterator = subscriptions.entrySet().iterator();
        while (iterator.hasNext()) {
            Map.Entry<String, Set<String>> entry = iterator.next();
            Set<String> userIds = entry.getValue();
            if (userIds.contains(userId)) {
                userIds.remove(userId);
                // 若订阅组为空，移除并停止直播（如果是直播类型）
                if (userIds.isEmpty()) {
                    String subscriptionKey = entry.getKey();
                    if (subscriptionKey.contains(MessageType.LIVESTREAM.getType())) {
                        String sn = subscriptionKey.split(":")[0];
                        _liveStreamService.StopLiveStreaming(sn);
                        log.info("设备[{}]无订阅者，停止直播", sn);
                    }
                    iterator.remove(); // 安全移除空订阅组
                }
            }
        }
    }

    /**
     * 向订阅了特定设备特定类型的用户发送消息
     */
    public void sendMessageToSubscribers(String sn, String type, String content) {
        String subscriptionKey = getSubscriptionKey(sn, type);
        Set<String> subscriberIds = subscriptions.getOrDefault(subscriptionKey, new HashSet<>());

        if (subscriberIds.isEmpty()) {
            return;
        }

        try {
            for (String userId : subscriberIds) {
                WebSocketSession session = userSessions.get(userId);
                if (session == null || !session.isOpen()) {
                    userSessions.remove(userId);
                    sessionLocks.remove(session);
                    userLastHeartbeatTime.remove(userId); // 清理心跳时间
                    continue;
                }

                // 同步发送消息，避免并发冲突
                Object lock = sessionLocks.get(session);
                if (lock == null) {
                    continue;
                }
                synchronized (lock) {
                    session.sendMessage(new TextMessage(content));
                    log.debug("向用户[{}]发送 设备[{}]的[{}]类型消息:{}", userId, sn, type, content);
                }
            }
        } catch (IOException e) {
            log.error("发送消息错误：{}", e.getMessage());
        }
    }

    /**
     * 通用发送消息方法（封装同步逻辑）
     */
    private void sendMessage(WebSocketSession session, String content) throws IOException {
        Object lock = sessionLocks.get(session);
        if (lock != null && session.isOpen()) {
            synchronized (lock) {
                session.sendMessage(new TextMessage(content));
            }
        }
    }

    /**
     * 生成订阅标识（sn+type的组合）
     */
    private String getSubscriptionKey(String sn, String type) {
        return sn + ":" + type;
    }

    // ====================== 销毁线程池（可选，防止内存泄漏） ======================

    public void destroy() {
        delayExecutor.shutdown();
        heartbeatCheckExecutor.shutdown();
        try {
            if (!delayExecutor.awaitTermination(1, TimeUnit.SECONDS)) {
                delayExecutor.shutdownNow();
            }
            if (!heartbeatCheckExecutor.awaitTermination(1, TimeUnit.SECONDS)) {
                heartbeatCheckExecutor.shutdownNow();
            }
        } catch (InterruptedException e) {
            delayExecutor.shutdownNow();
            heartbeatCheckExecutor.shutdownNow();
        }
        log.info("WebSocket线程池已销毁");
    }
}