package com.xiaopeng.pushMessage.webSocket.service;

import io.netty.channel.Channel;
import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;

import java.util.*;
import java.util.concurrent.ConcurrentHashMap;

/**
 * 基于 AppUser 的 WebSocket 连接管理器
 * 使用 Spring WebSocketSession（共用 Spring Boot HTTP 端口）
 * 支持按用户 ID 管理连接，一个用户可以有多个设备连接
 */
@Component
@Slf4j
public class WebSocketUserChannelConnectionManager {

    /**
     * Key: 用户ID (appUserId)
     * Value: 该用户的所有 WebSocketSession 集合
     */
    private static final ConcurrentHashMap<String, Set<WebSocketSession>> userConnections = new ConcurrentHashMap<>();

    /**
     * Key: session.getId()
     * Value: 用户ID (appUserId)
     */
    private static final ConcurrentHashMap<String, String> sessionToUser = new ConcurrentHashMap<>();

    /**
     * Key: session.getId()
     * Value: WebSocketSession
     */
    private static final ConcurrentHashMap<String, WebSocketSession> allConnections = new ConcurrentHashMap<>();

    // ==================== 连接管理 ====================

    /**
     * 添加用户连接
     */
    public void addUserConnection(String appUserId, WebSocketSession session) {
        String sessionId = session.getId();

        userConnections.computeIfAbsent(appUserId, k -> ConcurrentHashMap.newKeySet()).add(session);
        sessionToUser.put(sessionId, appUserId);
        allConnections.put(sessionId, session);

        log.info("用户连接已添加，用户ID: {}, sessionId: {}, 该用户连接数: {}",
                appUserId, sessionId, userConnections.get(appUserId).size());
    }

    /**
     * 移除用户连接
     */
    public void removeUserConnection(WebSocketSession session) {
        String sessionId = session.getId();
        String appUserId = sessionToUser.get(sessionId);

        if (appUserId != null) {
            Set<WebSocketSession> userSessions = userConnections.get(appUserId);
            if (userSessions != null) {
                userSessions.remove(session);
                if (userSessions.isEmpty()) {
                    userConnections.remove(appUserId);
                }
            }
            sessionToUser.remove(sessionId);
            log.info("用户连接已移除，用户ID: {}, sessionId: {}, 该用户剩余连接数: {}",
                    appUserId, sessionId, userSessions != null ? userSessions.size() : 0);
        }

        allConnections.remove(sessionId);
    }

    // ==================== 消息发送 ====================

    /**
     * 向指定用户的所有设备发送消息
     */
    public int sendMessageToUser(String appUserId, String message) {
        Set<WebSocketSession> sessions = userConnections.get(appUserId);
        if (sessions == null || sessions.isEmpty()) {
            log.warn("用户 {} 没有活跃连接", appUserId);
            return 0;
        }

        int successCount = 0;
        for (WebSocketSession session : sessions) {
            if (session != null && session.isOpen()) {
                try {
                    synchronized (session) {
                        session.sendMessage(new TextMessage(message));
                    }
                    successCount++;
                } catch (Exception e) {
                    log.error("向用户 {} 发送消息失败，sessionId: {}, 错误: {}",
                            appUserId, session.getId(), e.getMessage());
                }
            }
        }

        log.info("向用户 {} 发送消息完成，成功发送到 {} 个设备", appUserId, successCount);
        return successCount;
    }

    /**
     * 向指定 session 发送消息
     */
    public boolean sendMessageToChannel(String sessionId, String message) {
        WebSocketSession session = allConnections.get(sessionId);
        if (session != null && session.isOpen()) {
            try {
                synchronized (session) {
                    session.sendMessage(new TextMessage(message));
                }
                log.info("消息已发送到连接: {}", sessionId);
                return true;
            } catch (Exception e) {
                log.error("发送消息失败，sessionId: {}, 错误: {}", sessionId, e.getMessage());
                return false;
            }
        } else {
            log.warn("连接不存在或已关闭，sessionId: {}", sessionId);
            return false;
        }
    }

    /**
     * 向所有连接广播消息
     */
    public int broadcastMessage(String message) {
        int successCount = 0;
        for (WebSocketSession session : allConnections.values()) {
            if (session != null && session.isOpen()) {
                try {
                    synchronized (session) {
                        session.sendMessage(new TextMessage(message));
                    }
                    successCount++;
                } catch (Exception e) {
                    log.error("广播消息失败，sessionId: {}, 错误: {}", session.getId(), e.getMessage());
                }
            }
        }
        log.info("广播消息完成，成功发送到 {} 个连接", successCount);
        return successCount;
    }

    /**
     * 向多个用户发送消息
     */
    public int sendMessageToUsers(List<String> appUserIds, String message) {
        int successUserCount = 0;
        for (String appUserId : appUserIds) {
            int deviceCount = sendMessageToUser(appUserId, message);
            if (deviceCount > 0) {
                successUserCount++;
            }
        }
        log.info("向 {} 个用户发送消息完成，成功发送到 {} 个用户", appUserIds.size(), successUserCount);
        return successUserCount;
    }

    // ==================== 查询 ====================

    public Set<WebSocketSession> getUserConnections(String appUserId) {
        return userConnections.getOrDefault(appUserId, Collections.emptySet());
    }

    public int getUserConnectionCount(String appUserId) {
        Set<WebSocketSession> sessions = userConnections.get(appUserId);
        return sessions != null ? sessions.size() : 0;
    }

    public int getTotalConnectionCount() {
        return allConnections.size();
    }

    public int getOnlineUserCount() {
        return userConnections.size();
    }

    public Set<String> getOnlineUserIds() {
        return userConnections.keySet();
    }

    public boolean isUserOnline(String appUserId) {
        Set<WebSocketSession> sessions = userConnections.get(appUserId);
        if (sessions == null || sessions.isEmpty()) {
            return false;
        }
        return sessions.stream().anyMatch(WebSocketSession::isOpen);
    }

    public boolean isConnectionExists(String sessionId) {
        WebSocketSession session = allConnections.get(sessionId);
        return session != null && session.isOpen();
    }

    /**
     * 根据 sessionId 获取用户ID
     */
    public String getUserIdBySessionId(String sessionId) {
        return sessionToUser.get(sessionId);
    }

    public Map<String, Object> getConnectionStats() {
        Map<String, Object> stats = new HashMap<>();
        stats.put("totalConnections", getTotalConnectionCount());
        stats.put("onlineUsers", getOnlineUserCount());
        stats.put("onlineUserIds", getOnlineUserIds());

        Map<String, Integer> userConnectionCounts = new HashMap<>();
        for (Map.Entry<String, Set<WebSocketSession>> entry : userConnections.entrySet()) {
            userConnectionCounts.put(entry.getKey(), entry.getValue().size());
        }
        stats.put("userConnectionCounts", userConnectionCounts);

        return stats;
    }
}