FightSystem/FightSystem_9/src/de/steamwar/fightsystem/utils/TechHider9.java

/*
    This file is a part of the SteamWar software.

    Copyright (C) 2021  SteamWar.de-Serverteam

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package de.steamwar.fightsystem.utils;

import com.comphenix.tinyprotocol.Reflection;
import de.steamwar.fightsystem.Config;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.UnpooledByteBufAllocator;
import org.bukkit.Bukkit;
import org.bukkit.entity.Player;

import java.util.List;
import java.util.Set;
import java.util.function.UnaryOperator;
import java.util.logging.Level;
import java.util.stream.Collectors;

public class TechHider9 extends TechHider8 {

    private static final UnaryOperator<Object> mapChunkCloner = ProtocolAPI.shallowCloneGenerator(mapChunkPacket);

    private static final Reflection.FieldAccessor<Integer> mapChunkX = Reflection.getField(mapChunkPacket, int.class, 0);
    private static final Reflection.FieldAccessor<Integer> mapChunkZ = Reflection.getField(mapChunkPacket, int.class, 1);
    private static final Reflection.FieldAccessor<Integer> mapChunkBitMask = Reflection.getField(mapChunkPacket, int.class, 2);
    private static final Reflection.FieldAccessor<List> mapChunkBlockEntities = Reflection.getField(mapChunkPacket, List.class, 0);
    private static final Reflection.FieldAccessor<byte[]> mapChunkData = Reflection.getField(mapChunkPacket, byte[].class, 0);

    private static final Class<?> nbtTagCompound = Reflection.getClass("{nms.nbt}.NBTTagCompound");
    private static final Reflection.MethodInvoker nbtTagGetString = Reflection.getTypedMethod(nbtTagCompound, null, String.class, String.class);

    protected final Set<Integer> hiddenBlockIds = BlockIdWrapper.impl.getHiddenBlockIds();
    protected final int obfuscateWith = BlockIdWrapper.impl.getObfuscateWith();

    @Override
    public Object mapChunkHider(Player p, Object packet) {
        if(TechHider.bypass(p, mapChunkX.get(packet), mapChunkZ.get(packet)))
            return packet;

        packet = mapChunkCloner.apply(packet);
        mapChunkBlockEntities.set(packet, ((List<?>)mapChunkBlockEntities.get(packet)).stream().filter(
                nbttag -> Config.HiddenBlockEntities.contains((String) nbtTagGetString.invoke(nbttag, "id"))
        ).collect(Collectors.toList()));

        byte[] data = dataHider(mapChunkData.get(packet), mapChunkBitMask.get(packet));
        mapChunkData.set(packet, data);

        return packet;
    }

    protected byte[] dataHider(byte[] data, Integer primaryBitMask) {
        ByteBuf buffer = UnpooledByteBufAllocator.DEFAULT.directBuffer(data.length + 100);
        int i = 0;

        while(i < data.length){
            byte bitsPerBlock = data[i++];
            buffer.writeByte(bitsPerBlock);

            if(bitsPerBlock != 13){
                int paletteLength = TechHider.readVarInt(data, i);
                int paletteLengthLength = TechHider.readVarIntLength(data, i);
                buffer.writeBytes(data, i, paletteLengthLength);
                i += paletteLengthLength;

                for(int actPaletteId = 0; actPaletteId < paletteLength; actPaletteId++){
                    int entry = TechHider.readVarInt(data, i);
                    i += TechHider.readVarIntLength(data, i);

                    if(hiddenBlockIds.contains(entry)){
                        entry = obfuscateWith;
                    }
                    buffer.writeBytes(TechHider.writeVarInt(entry));
                }
            }else{
                buffer.writeByte(data[++i]); //Empty palette
                Bukkit.getLogger().log(Level.SEVERE, "Full chunk occured");
            }

            int dataArrayLength = TechHider.readVarInt(data, i);
            int dataArrayLengthLength = TechHider.readVarIntLength(data, i);
            buffer.writeBytes(data, i, dataArrayLength*8 + dataArrayLengthLength);
            i += dataArrayLengthLength;
            i += dataArrayLength * 8;

            buffer.writeBytes(data, i, 4096);
            i += 4096; //Skylight (Not in Nether/End!!!) 2048 + Blocklight 2048
        }

        data = new byte[buffer.readableBytes()];
        buffer.readBytes(data);
        return data;
    }
}