BauSystem/BauSystem_Main/src/de/steamwar/bausystem/commands/CommandTPSLimiter.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.bausystem.commands;

import com.comphenix.protocol.PacketType;
import com.comphenix.protocol.ProtocolLibrary;
import com.comphenix.protocol.events.PacketAdapter;
import com.comphenix.protocol.events.PacketEvent;
import com.comphenix.protocol.reflect.StructureModifier;
import com.comphenix.protocol.wrappers.WrappedWatchableObject;
import de.steamwar.bausystem.BauSystem;
import de.steamwar.bausystem.Permission;
import de.steamwar.bausystem.world.Welt;
import net.md_5.bungee.api.ChatMessageType;
import net.md_5.bungee.api.chat.TextComponent;
import net.minecraft.server.v1_15_R1.*;
import org.bukkit.Bukkit;
import org.bukkit.World;
import org.bukkit.command.Command;
import org.bukkit.command.CommandExecutor;
import org.bukkit.command.CommandSender;
import org.bukkit.craftbukkit.v1_15_R1.entity.CraftEntity;
import org.bukkit.craftbukkit.v1_15_R1.entity.CraftPlayer;
import org.bukkit.craftbukkit.v1_15_R1.entity.CraftTNTPrimed;
import org.bukkit.entity.Entity;
import org.bukkit.entity.Player;
import org.bukkit.scheduler.BukkitTask;

import java.util.List;

public class CommandTPSLimiter implements CommandExecutor {

    private static int currentTPSLimit = 20;
    private static World world = Bukkit.getWorlds().get(0);
    private long lastTime = System.nanoTime();
    private long currentTime = System.nanoTime();

    private BukkitTask tpsLimiter = null;

    public CommandTPSLimiter() {
        ProtocolLibrary.getProtocolManager().addPacketListener(new PacketAdapter(BauSystem.getPlugin(), PacketType.Play.Server.ENTITY_METADATA) {
            @Override
            public void onPacketSending(PacketEvent event) {
                // if (tpsLimiterNotActive()) return;
                if (event.getPacket().getEntityModifier(world).read(0) == null) return;
                if (!(event.getPacket().getEntityModifier(world).read(0) instanceof CraftTNTPrimed)) return;
                System.out.println("ENTITY_METADATA: " + event.getPacket().getIntegers().read(0));
                List<WrappedWatchableObject> dataWatcherObjectList = event.getPacket().getWatchableCollectionModifier().read(0);
                // getByIndex(dataWatcherObjectList, 5).setValue(true);
                getByIndex(dataWatcherObjectList, 7).setValue((int) ((20.0 / currentTPSLimit) * 80));
                // System.out.println(dataWatcherObjectList);
                event.getPacket().getWatchableCollectionModifier().write(0, dataWatcherObjectList);
            }
        });
        ProtocolLibrary.getProtocolManager().addPacketListener(new PacketAdapter(BauSystem.getPlugin(), PacketType.Play.Server.REL_ENTITY_MOVE) {
            @Override
            public void onPacketSending(PacketEvent event) {
                if (tpsLimiterNotActive()) return;
                if (event.getPacket().getEntityModifier(world).read(0) == null) return;
                if (!(event.getPacket().getEntityModifier(world).read(0) instanceof CraftTNTPrimed)) return;
                System.out.println("REL_ENTITY_MOVE: " + event.getPacket().getIntegers().read(0));
                StructureModifier<Integer> structureModifier = event.getPacket().getIntegers();
                // structureModifier.write(1, 0);
                // structureModifier.write(2, 0);
                // structureModifier.write(3, 0);

                Entity entity = event.getPacket().getEntityModifier(world).read(0);
                // System.out.println(entity.getLocation());
                net.minecraft.server.v1_15_R1.Entity serverEntity = ((CraftEntity) entity).getHandle();

                PacketPlayOutEntityTeleport packetPlayOutEntityTeleport = new PacketPlayOutEntityTeleport(serverEntity);
                sendPlayers(packetPlayOutEntityTeleport);

                PacketPlayOutEntityMetadata packetPlayOutEntityMetadata = new PacketPlayOutEntityMetadata(serverEntity.getId(), serverEntity.getDataWatcher(), true);
                sendPlayers(packetPlayOutEntityMetadata);

                Vec3D vec3D = serverEntity.getMot();
                PacketPlayOutEntityVelocity packetPlayOutEntityVelocity = new PacketPlayOutEntityVelocity(serverEntity.getId(), new Vec3D(vec3D.x / (20.0 / currentTPSLimit), vec3D.y / (20.0 / currentTPSLimit), vec3D.z / (20.0 / currentTPSLimit)));
                sendPlayers(packetPlayOutEntityVelocity);
            }
        });
        ProtocolLibrary.getProtocolManager().addPacketListener(new PacketAdapter(BauSystem.getPlugin(), PacketType.Play.Server.ENTITY_VELOCITY) {
            @Override
            public void onPacketSending(PacketEvent event) {

            }
        });
    }

    private boolean tpsLimiterNotActive() {
        return currentTPSLimit == 20;
    }

    private void sendPlayers(Packet<?> packet) {
        Bukkit.getOnlinePlayers().forEach(player -> {
            PlayerConnection connection = ((CraftPlayer)player).getHandle().playerConnection;
            connection.sendPacket(packet);
        });
    }

    private WrappedWatchableObject getByIndex(List<WrappedWatchableObject> wrappedWatchableObjects, int index) {
        for (WrappedWatchableObject wrappedWatchableObject : wrappedWatchableObjects) {
            if (wrappedWatchableObject.getIndex() == index) return wrappedWatchableObject;
        }
        return null;
    }

    private boolean permissionCheck(Player player) {
        if (Welt.noPermission(player, Permission.world)) {
            player.sendMessage(BauSystem.PREFIX + "§cDu darfst hier nicht den TPS-Limiter nutzen");
            return false;
        }
        return true;
    }

    @Override
    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
        if (!(sender instanceof Player)) {
            return false;
        } else if (args.length == 0) {
            sender.sendMessage(BauSystem.PREFIX + "Jetziges TPS limit: " + currentTPSLimit);
            sender.sendMessage(BauSystem.PREFIX + "Ändere das TPS limit mit: §8/§etpslimit §8[§7TPS§8|§edefault§8]");
            return false;
        }
        Player player = (Player) sender;
        // TODO: Remove on final push
        // if (permissionCheck(player)) return false;

        String tpsLimit = args[0];
        if (tpsLimit.equals("default")) {
            currentTPSLimit = 20;
            sendNewTPSLimitMessage();
            tpsLimiter();
            return false;
        }

        try {
            int tpsLimitInt = Integer.parseInt(tpsLimit);
            if (tpsLimitInt < 1 || tpsLimitInt > 20) {
                sendInvalidArgumentMessage(player);
                return false;
            }
            currentTPSLimit = tpsLimitInt;
            sendNewTPSLimitMessage();
            tpsLimiter();
        } catch (NumberFormatException e) {
            sendInvalidArgumentMessage(player);
        }

        return false;
    }

    private void sendNewTPSLimitMessage() {
        Bukkit.getOnlinePlayers().forEach(p -> p.spigot().sendMessage(ChatMessageType.ACTION_BAR, TextComponent.fromLegacyText("§eTPS limit auf " + currentTPSLimit + " gesetzt.")));
    }

    private void sendInvalidArgumentMessage(Player player) {
        player.sendMessage(BauSystem.PREFIX + "§cNur Zahlen zwischen 1 und 20, und 'default' erlaubt.");
    }

    private void tpsLimiter() {
        if (currentTPSLimit == 20) {
            if (tpsLimiter == null) return;
            tpsLimiter.cancel();
            tpsLimiter = null;
        } else {
            if (tpsLimiter != null) return;
            tpsLimiter = Bukkit.getScheduler().runTaskTimer(BauSystem.getPlugin(), () -> {
                lastTime = currentTime;
                currentTime = System.nanoTime();

                long timeDelta = (currentTime - lastTime) / 1000000;
                long neededDelta = 1000 / currentTPSLimit;

                if (neededDelta - timeDelta < 1) {
                    return;
                }

                try {
                    Thread.sleep(neededDelta - timeDelta);
                    currentTime = System.nanoTime();
                } catch (InterruptedException e) {
                    Thread.currentThread().interrupt();
                }
            }, 0, 1);
        }
    }

    public static int getCurrentTPSLimit() {
        return currentTPSLimit;
    }

    private void setMotion(Entity entity) {

    }

}