PacketsListener - PacketInjector

package fr.vinetos.packetlistener;

import io.netty.channel.Channel;
import org.bukkit.entity.Player;

import java.lang.reflect.Field;

/**
 * Created by VINETOS on 29/12/2015.
 */
public class PacketInjector {

    private Field EntityPlayer_playerConnection;
    private Class<?> PlayerConnection;
    private Field PlayerConnection_networkManager;

    private Class<?> NetworkManager;
    private Field channel;
    private Field packetListener;//net.minecraft

    public PacketInjector() {
        try {
            EntityPlayer_playerConnection = Reflection.getField(Reflection.getClass("{nms}.EntityPlayer"), "playerConnection");

            PlayerConnection = Reflection.getClass("{nms}.PlayerConnection");
            PlayerConnection_networkManager = Reflection.getField(PlayerConnection, "networkManager");

            NetworkManager = Reflection.getClass("{nms}.NetworkManager");
            if(Reflection.getNmsVersion().equals("v1_8_R2")){
                channel = Reflection.getField(NetworkManager, "k");
            }else
            if(Reflection.getNmsVersion().equals("v1_8_R3")){
                channel = Reflection.getField(NetworkManager, "channel");
            }
            packetListener = Reflection.getField(NetworkManager, "m");//PacketListener
        } catch (Throwable t) {
            t.printStackTrace();
        }
    }

    public void addPlayer(Player p) {
        try {
            Channel ch = getChannel(getNetworkManager(Reflection.getNmsPlayer(p)));
            if(ch.pipeline().get("PacketInjector") == null) {
                PacketHandler h = new PacketHandler(p);
                ch.pipeline().addBefore("packet_handler", "PacketInjector", h);
            }
        } catch (Throwable t) {
            t.printStackTrace();
        }
    }

    public void removePlayer(Player p) {
        try {
            Channel ch = getChannel(getNetworkManager(Reflection.getNmsPlayer(p)));
            if(ch.pipeline().get("PacketInjector") != null) {
                ch.pipeline().remove("PacketInjector");
            }
        } catch (Throwable t) {
            t.printStackTrace();
        }
    }

    private Object getNetworkManager(Object ep) {
        return Reflection.getFieldValue(PlayerConnection_networkManager, Reflection.getFieldValue(EntityPlayer_playerConnection, ep));
    }

    private Channel getChannel(Object networkManager) {
        Channel ch = null;
        try {
            ch = Reflection.getFieldValue(channel, networkManager);
        } catch (Exception e) {
            ch = Reflection.getFieldValue(packetListener, networkManager);
        }
        return ch;
    }
}