package com.monkeylessey.websocket;

import io.netty.channel.Channel;
import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.util.concurrent.GlobalEventExecutor;

import java.util.Map;
import java.util.Objects;
import java.util.concurrent.ConcurrentHashMap;

/**
 * @author：xp
 * @date：2024/4/19 14:02
 */
public class NettyConnect {

    /**
     * 定义一个channel组，管理所有的channel
     * GlobalEventExecutor.INSTANCE 是全局的事件执行器，是一个单例
     */
    private static ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);

    /**
     * 存放用户与Chanel的对应信息，用于给指定用户发送消息
     */
    private static ConcurrentHashMap<String, Channel> userChannelMap = new ConcurrentHashMap<>(128);

    private NettyConnect() {}

    /**
     * 获取channel组
     * @return
     */
    public static ChannelGroup getChannelGroup() {
        return channelGroup;
    }

    /**
     * 移除channel时，同时移除用户对应关系
     *
     * @param channel
     */
    public static void removeChannel(Channel channel) {
        String userId = null;
        for (Map.Entry<String, Channel> channelEntry : userChannelMap.entrySet()) {
            if (Objects.equals(channel, channelEntry.getValue())) {
                userId = channelEntry.getKey();
                break;
            }
        }
        if (Objects.nonNull(userId)) {
            userChannelMap.remove(userId);
        }
        channelGroup.remove(channel);
    }

    /**
     * 获取用户channel map
     * @return
     */
    public static ConcurrentHashMap<String, Channel> getUserChannelMap(){
        return userChannelMap;
    }

    /**
     * 移除用户关系时，同时移除连接
     *
     * @param userId
     */
    public static void removeUserChannel(Integer userId) {
        Channel channel = userChannelMap.get(userId);
        if (Objects.nonNull(userId)) {
            userChannelMap.remove(userId);
            channelGroup.remove(channel);
        }
    }

}