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 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.entity.Player;
import org.bukkit.entity.TNTPrimed;
import org.bukkit.scheduler.BukkitTask;

import java.util.HashSet;
import java.util.Set;

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() {

    }

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

    private void sendPlayers(Set<? extends Packet<?>> packets) {
        Bukkit.getOnlinePlayers().forEach(player -> {
            PlayerConnection connection = ((CraftPlayer)player).getHandle().playerConnection;
            for (Packet<?> p : packets) {
                connection.sendPacket(p);
            }
        });
    }

    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(), () -> {
                sendTntMetaData();

                Vec3D noMotion = new Vec3D(0, 0, 0);
                Set<PacketPlayOutEntityVelocity> velocityPackets = new HashSet<>();
                world.getEntitiesByClasses(TNTPrimed.class).forEach(entity -> {
                    velocityPackets.add(new PacketPlayOutEntityVelocity(entity.getEntityId(), noMotion));
                });

                for (int i = 0; i < (20 / currentTPSLimit); i++) {
                    sleepUntilNextTick();
                    sendTntData();
                    sendPlayers(velocityPackets);
                }
            }, 0, 1);
        }
    }

    private void sleepUntilNextTick() {
        lastTime = currentTime;
        currentTime = System.nanoTime();

        long timeDelta = (currentTime - lastTime) / 1000000;
        long neededDelta = 50;

        if (neededDelta - timeDelta < 0) {
            return;
        }

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

    private void sendTntMetaData() {
        world.getEntitiesByClasses(TNTPrimed.class).forEach(entity -> {
            net.minecraft.server.v1_15_R1.Entity serverEntity = ((CraftEntity) entity).getHandle();

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

    private void sendTntData() {
        Set<Packet<?>> packets = new HashSet<>();

        world.getEntitiesByClasses(TNTPrimed.class).forEach(entity -> {
            net.minecraft.server.v1_15_R1.Entity serverEntity = ((CraftEntity) entity).getHandle();
            packets.add(new PacketPlayOutEntityTeleport(serverEntity));
            // packets.add(new PacketPlayOutEntityVelocity(serverEntity.getId(), noMotion));
        });

        sendPlayers(packets);
    }

    public static int getCurrentTPSLimit() {
        return currentTPSLimit;
    }

}