FightSystem/FightSystem_12/src/de/steamwar/fightsystem/utils/TechHider12.java

/* 
    This file is a part of the SteamWar software.
    
    Copyright (C) 2020  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.protocol.PacketType;
import com.comphenix.protocol.events.PacketAdapter;
import com.comphenix.protocol.events.PacketContainer;
import com.comphenix.protocol.events.PacketEvent;
import com.comphenix.protocol.reflect.StructureModifier;
import com.comphenix.protocol.wrappers.nbt.NbtBase;
import com.comphenix.protocol.wrappers.nbt.NbtCompound;
import de.steamwar.fightsystem.Config;
import de.steamwar.fightsystem.FightSystem;
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.logging.Level;

import static de.steamwar.fightsystem.utils.TechHider.bypass;

public class TechHider12 extends PacketAdapter {

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

    public TechHider12() {
        super(FightSystem.getPlugin(), PacketType.Play.Server.MAP_CHUNK);
    }

    @Override
    public void onPacketSending(PacketEvent e) {
        PacketContainer packet = e.getPacket();
        StructureModifier<Integer> ints = packet.getIntegers();

        int chunkX = ints.read(0);
        int chunkZ = ints.read(1);
        Player p = e.getPlayer();
        if(bypass(p, chunkX, chunkZ))
            return;

        packet = packet.shallowClone();
        e.setPacket(packet);
        StructureModifier<List<NbtBase<?>>> list = packet.getListNbtModifier();
        List<NbtBase<?>> nmsTags = list.read(0);
        boolean changed = false;
        for(int i = nmsTags.size() - 1; i >= 0; i--){
            NbtCompound nbt = (NbtCompound)nmsTags.get(i);
            if(Config.HiddenBlockEntities.contains(nbt.getString("id"))){
                nmsTags.remove(i);
                changed = true;
            }
        }
        if(changed)
            list.write(0, nmsTags);

        changed = false;
        StructureModifier<byte[]> byteArray = packet.getByteArrays();
        byte [] data = byteArray.read(0);
        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;
                        changed = true;
                    }
                    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
        }

        if(changed){
            data = new byte[buffer.readableBytes()];
            buffer.readBytes(data);
            byteArray.write(0, data);
        }
    }
}