FightSystem/src/me/yaruma/fightsystem/utils/TechHider.java

package me.yaruma.fightsystem.utils;

import com.comphenix.protocol.PacketType;
import com.comphenix.protocol.ProtocolLibrary;
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.BlockPosition;
import com.comphenix.protocol.wrappers.ChunkCoordIntPair;
import com.comphenix.protocol.wrappers.MultiBlockChangeInfo;
import com.comphenix.protocol.wrappers.WrappedBlockData;
import com.comphenix.protocol.wrappers.nbt.NbtCompound;
import com.comphenix.protocol.wrappers.nbt.NbtFactory;
import com.google.common.primitives.Bytes;
import me.yaruma.fightsystem.FightSystem;
import me.yaruma.fightsystem.fight.Fight;
import me.yaruma.fightsystem.fight.FightTeam;
import org.bukkit.GameMode;
import org.bukkit.Material;
import org.bukkit.entity.Player;

import java.util.ArrayList;
import java.util.List;

public class TechHider {

    private static int arenaMinX;
    private static int arenaMaxX;
    private static int arenaMinZ;
    private static int arenaMaxZ;
    private static int blueMinX;
    private static int blueMaxX;
    private static int blueMinZ;
    private static int blueMaxZ;
    private static int redMinX;
    private static int redMaxX;
    private static int redMinZ;
    private static int redMaxZ;
    private static int obfuscateShift4;
    private static Material obfuscateMaterial;

    public static void init(){
        arenaMinX = Config.ArenaMinX / 16 - (Config.ArenaMinX % 16 < 0 ? 1 : 0);
        arenaMinZ = Config.ArenaMinZ / 16 - (Config.ArenaMinZ % 16 < 0 ? 1 : 0);
        arenaMaxX = Config.ArenaMaxX / 16 + (Config.ArenaMaxX % 16 > 0 ? 1 : 0);
        arenaMaxZ = Config.ArenaMaxZ / 16 + (Config.ArenaMaxZ % 16 > 0 ? 1 : 0);
        blueMinX = Config.TeamBlueCornerX / 16 - (Config.TeamBlueCornerX % 16 < 0 ? 1 : 0);
        blueMinZ = Config.TeamBlueCornerZ / 16 - (Config.TeamBlueCornerZ % 16 < 0 ? 1 : 0);
        int max = Config.TeamBlueCornerX + Config.SchemsizeX;
        blueMaxX =  max / 16 + (max % 16 > 0 ? 1 : 0);
        max = Config.TeamBlueCornerZ + Config.SchemsizeZ;
        blueMaxZ = max / 16 + (max % 16 > 0 ? 1 : 0);
        redMinX = Config.TeamRedCornerX / 16 - (Config.TeamRedCornerX % 16 < 0 ? 1 : 0);
        redMinZ = Config.TeamRedCornerZ / 16 - (Config.TeamRedCornerZ % 16 < 0 ? 1 : 0);
        max = Config.TeamRedCornerX + Config.SchemsizeX;
        redMaxX = max / 16 + (max % 16 > 0 ? 1 : 0);
        max = Config.TeamRedCornerZ + Config.SchemsizeZ;
        redMaxZ = max / 16 + (max % 16 > 0 ? 1 : 0);
        obfuscateShift4 = Config.ObfuscateWith << 4;
        //noinspection deprecation
        obfuscateMaterial = Material.getMaterial(Config.ObfuscateWith);

        ProtocolLibrary.getProtocolManager().addPacketListener(new PacketAdapter(FightSystem.getPlugin(), PacketType.Play.Server.MAP_CHUNK) {
            @Override
            public void onPacketSending(PacketEvent e) {
                PacketContainer packet = e.getPacket();
                StructureModifier<Integer> ints = packet.getIntegers();
                StructureModifier<byte[]> byteArray = packet.getByteArrays();
                StructureModifier<List> list = packet.getSpecificModifier(List.class);
                List nmsTags = list.read(0);

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


                boolean changed = false;
                for(int i = nmsTags.size() - 1; i >= 0; i--){
                    NbtCompound nbt = NbtFactory.fromNMSCompound(nmsTags.get(i));
                    if(Config.HiddenBlockEntities.contains(nbt.getString("id"))){
                        nmsTags.remove(i);
                        changed = true;
                    }
                }
                if(changed){
                    list.write(0, nmsTags);
                }

                changed = false;
                byte [] data = byteArray.read(0);
                List<Byte> newData = new ArrayList<>(Bytes.asList(data));
                int i = 0;

                while(i < newData.size()){
                    byte bitsPerBlock = newData.get(i++);
                    if(bitsPerBlock < 4)
                        bitsPerBlock = 4;
                    else if(bitsPerBlock > 8){
                        bitsPerBlock = 13;
                        i++;
                    }

                    if(bitsPerBlock != 13){
                        int paletteLength = readVarInt(Bytes.toArray(newData), i);
                        i += readVarIntLength(Bytes.toArray(newData), i);
                        for(int actPaletteId = 0; actPaletteId < paletteLength; actPaletteId++){
                            int actPalette = readVarInt(Bytes.toArray(newData), i);
                            int actPaletteLength = readVarIntLength(Bytes.toArray(newData), i);

                            int blockId = actPalette >> 4;
                            if(Config.HiddenBlocks.contains(blockId)){
                                byte[] a = writeVarInt(obfuscateShift4);
                                for(int j = 0; j < actPaletteLength; j++){
                                    newData.remove(i);
                                }
                                for(byte b : a){
                                    newData.add(i++, b);
                                }
                                changed = true;
                            }else{
                                i += actPaletteLength;
                            }
                        }
                        int dataArrayLength = readVarInt(Bytes.toArray(newData), i);
                        i += readVarIntLength(Bytes.toArray(newData), i);
                        i += dataArrayLength * 8;
                    }else{
                        System.out.println("Chunk with global palette!");
                        int dataArrayLength = readVarInt(Bytes.toArray(newData), i);
                        i += readVarIntLength(Bytes.toArray(newData), i);
                        int arrayEnd = dataArrayLength * 8 + i;
                        int bitsOver = 8; //9 bits (id) + 4 bits (metadata)
                        final int globalMask = 0x000001FF;
                        final byte replacement = 0x01;
                        while(i < arrayEnd){
                            int blockId = (newData.get(i++) & (globalMask >> 9 - bitsOver)) << 9-bitsOver;
                            blockId += newData.get(i) >> bitsOver-1;
                            if(Config.HiddenBlocks.contains(blockId)){
                                System.out.println("Hidden Block found!");
                            }
                            bitsOver -= 5; // 13-8
                            if(bitsOver < 1){
                                i++;
                                bitsOver += 8;
                            }
                        }
                        //i += dataArrayLength * 8;
                    }

                    i += 4096; //Skylight (Not in Nether/End!!!) 2048 + Blocklight 2048
                }

                if(changed){
                    byteArray.write(0, Bytes.toArray(newData));
                }
            }
        });
        ProtocolLibrary.getProtocolManager().addPacketListener(new PacketAdapter(FightSystem.getPlugin(), PacketType.Play.Server.BLOCK_CHANGE) {
            @SuppressWarnings("deprecation")
            @Override
            public void onPacketSending(PacketEvent e) {
                PacketContainer packet = e.getPacket();
                StructureModifier<WrappedBlockData> blockStructure = packet.getBlockData();
                BlockPosition pos = packet.getBlockPositionModifier().read(0);

                Player p = e.getPlayer();
                if(bypass(p, pos.getX() / 16, pos.getZ() / 16))
                    return;

                WrappedBlockData block = blockStructure.read(0);
                if(Config.HiddenBlocks.contains(block.getType().getId())){
                    block.setType(obfuscateMaterial);
                    blockStructure.write(0, block);
                }
            }
        });
        ProtocolLibrary.getProtocolManager().addPacketListener(new PacketAdapter(FightSystem.getPlugin(), PacketType.Play.Server.MULTI_BLOCK_CHANGE) {
            @SuppressWarnings("deprecation")
            @Override
            public void onPacketSending(PacketEvent e) {
                PacketContainer packet = e.getPacket();
                StructureModifier<MultiBlockChangeInfo[]> blockStructure = packet.getMultiBlockChangeInfoArrays();
                MultiBlockChangeInfo[] changes = blockStructure.read(0);

                Player p = e.getPlayer();
                ChunkCoordIntPair pos = changes[0].getChunk();
                if(bypass(p, pos.getChunkX(), pos.getChunkZ()))
                    return;

                boolean changed = false;
                for(MultiBlockChangeInfo mbci : changes){
                    WrappedBlockData block = mbci.getData();
                    if(Config.HiddenBlocks.contains(block.getType().getId())){
                        changed = true;
                        block.setType(obfuscateMaterial);
                        mbci.setData(block);
                    }
                }

                if(changed){
                    blockStructure.write(0, changes);
                }
            }
        });
        ProtocolLibrary.getProtocolManager().addPacketListener(new PacketAdapter(FightSystem.getPlugin(), PacketType.Play.Server.BLOCK_ACTION) {
            @Override
            public void onPacketSending(PacketEvent e) {
                PacketContainer packet = e.getPacket();
                BlockPosition pos = packet.getBlockPositionModifier().read(0);
                Player p = e.getPlayer();
                if(bypass(p, pos.getX() / 16, pos.getZ() / 16))
                    return;

                e.setCancelled(true);
            }
        });
        ProtocolLibrary.getProtocolManager().addPacketListener(new PacketAdapter(FightSystem.getPlugin(), PacketType.Play.Client.USE_ITEM) {
            @Override
            public void onPacketReceiving(PacketEvent e) {
                Player p = e.getPlayer();

                if(p.getGameMode() == GameMode.SPECTATOR){
                    e.setCancelled(true);
                }
            }
        });
        ProtocolLibrary.getProtocolManager().addPacketListener(new PacketAdapter(FightSystem.getPlugin(), PacketType.Play.Client.USE_ENTITY) {
            @Override
            public void onPacketReceiving(PacketEvent e) {
                Player p = e.getPlayer();

                if(p.getGameMode() == GameMode.SPECTATOR){
                    e.setCancelled(true);
                }
            }
        });
    }

    private static boolean bypass(Player p, int chunkX, int chunkZ){
        if( ! (arenaMinX <= chunkX && chunkX <= arenaMaxX && arenaMinZ <= chunkZ && chunkZ <= arenaMaxZ)){
            //Außerhalb der Arena
            return true;
        }

        FightTeam ft = Fight.getPlayerTeam(p);
        if(ft == null){
            return false;
        }else if(ft == Fight.getBlueTeam()){
            return Config.Entern || ! (redMinX <= chunkX && chunkX <= redMaxX && redMinZ <= chunkZ && chunkZ <= redMaxZ);
        }else{
            return Config.Entern || ! (blueMinX <= chunkX && chunkX <= blueMaxX && blueMinZ <= chunkZ && chunkZ <= blueMaxZ);
        }
    }

    private static int readVarInt(byte[] array, int startPos) {
        int numRead = 0;
        int result = 0;
        byte read;
        do {
            read = array[startPos + numRead];
            int value = (read & 0b01111111);
            result |= (value << (7 * numRead));

            numRead++;
            if (numRead > 5) {
                break;
            }
        } while ((read & 0b10000000) != 0);

        return result;
    }

    private static int readVarIntLength(byte[] array, int startPos) {
        int numRead = 0;
        byte read;
        do {
            read = array[startPos + numRead];
            numRead++;
            if (numRead > 5) {
                break;
            }
        } while ((read & 0b10000000) != 0);

        return numRead;
    }

    private static byte[] writeVarInt(int value) {
        ArrayList<Byte> buffer = new ArrayList<>();
        do {
            byte temp = (byte)(value & 0b01111111);
            // Note: >>> means that the sign bit is shifted with the rest of the number rather than being left alone
            value >>>= 7;
            if (value != 0) {
                temp |= 0b10000000;
            }
            buffer.add(temp);
        } while (value != 0);
        return Bytes.toArray(buffer);
    }
}