FakeArmor

EntityEquipmentManager.java

import org.bukkit.Bukkit;
import org.bukkit.entity.Entity;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.entity.EntityDamageEvent;
import org.bukkit.event.inventory.InventoryClickEvent;
import org.bukkit.event.inventory.InventoryType;
import org.bukkit.inventory.ItemStack;
import org.bukkit.plugin.Plugin;
import org.bukkit.scheduler.BukkitRunnable;
import org.bukkit.scheduler.BukkitTask;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;


public class EntityEquipmentManager implements Listener
{
    
    private Map<Integer, Map<Slot, ItemStack>> items = new HashMap<>();
    private Constructor<?> entityEquipmentConstructor;
    private Method getPlayerHandle;
    private Method sendPacket;
    private Method asNMSCopy;
    private Field playerConnection;
    private Plugin plugin;


    public EntityEquipmentManager(Plugin plugin)
    {
        this.plugin = plugin;
        String version = Bukkit.getServer().getClass().getPackage().getName().split( "\\." )[ 3 ];
        try
        {
            Class<?> entityPlayerClass = Class.forName( "net.minecraft.server." + version + ".EntityPlayer" );
            Class<?> craftPlayerClass = Class.forName( "org.bukkit.craftbukkit." + version + ".entity.CraftPlayer" );
            Class<?> craftItemStack = Class.forName( "org.bukkit.craftbukkit." + version + ".inventory.CraftItemStack" );
            Class<?> typePlayerConnection = Class.forName( "net.minecraft.server." + version + ".PlayerConnection" );
            Class<?> entityEquipmentClass = Class.forName( "net.minecraft.server." + version + ".PacketPlayOutEntityEquipment" );
            Class<?> nmsItemStack = Class.forName( "net.minecraft.server." + version + ".ItemStack" );
            entityEquipmentConstructor = entityEquipmentClass.getConstructor( int.class, int.class, nmsItemStack );
            asNMSCopy = craftItemStack.getMethod( "asNMSCopy", ItemStack.class );
            getPlayerHandle = craftPlayerClass.getMethod( "getHandle" );
            playerConnection = entityPlayerClass.getField( "playerConnection" );
            sendPacket = typePlayerConnection.getMethod( "sendPacket",
                    Class.forName( "net.minecraft.server." + version + ".Packet" ) );
        } catch ( ClassNotFoundException | NoSuchMethodException | NoSuchFieldException e )
        {
            e.printStackTrace();
        }
        plugin.getServer().getPluginManager().registerEvents( this, plugin );
    }

    public void setEquipment(Entity entity, Slot slot, ItemStack itemStack)
    {
        try
        {
            Object packet = entityEquipmentConstructor.newInstance( entity.getEntityId(), slot.ordinal(), asNMSCopy.invoke( null, itemStack ) );
            Map<Slot, ItemStack> tempMap;
            if ( items.containsKey( entity.getEntityId() ) )
            {
                tempMap = items.get( entity.getEntityId() );
            } else
            {
                tempMap = new HashMap<>();
                items.put( entity.getEntityId(), tempMap );
            }
            tempMap.put( slot, itemStack );
            Player targetedPlayer = null;
            if ( entity instanceof Player )
                targetedPlayer = ( Player ) entity;
            for ( Player player : Bukkit.getOnlinePlayers() )
            {
                if ( targetedPlayer != null && targetedPlayer.getName().equals( player.getName() ) ) continue;
                Object entityPlayer = getPlayerHandle.invoke( player );
                Object connection = playerConnection.get( entityPlayer );
                sendPacket.invoke( connection, packet );
            }
        } catch ( IllegalAccessException | InvocationTargetException | InstantiationException e )
        {
            e.printStackTrace();
        }
    }

    private void setArmor(Entity entity)
    {
        if ( items.containsKey( entity.getEntityId() ) )
        {
            items.get( entity.getEntityId() ).forEach( (slot, itemStack) ->
                    setEquipment( entity, slot, itemStack ) );
        }
    }

    private void setArmor(Entity entity, Slot slot)
    {
        new BukkitRunnable()
        {
            @Override
            public void run()
            {
                if ( items.containsKey( entity.getEntityId() ) )
                {
                    if ( items.get( entity.getEntityId() ).containsKey( slot ) )
                    {
                        ItemStack itemStack = items.get( entity.getEntityId() ).get( slot );
                        setEquipment( entity, slot, itemStack );
                    }
                }
            }
        }.runTaskLater( plugin, 2L );
    }


    @EventHandler
    public void onEntityDamage(EntityDamageEvent event)
    {

            new BukkitRunnable()
            {
                @Override
                public void run()
                {
                    setArmor( event.getEntity() );
                }
            }.runTaskLater( plugin, 2L );
    }

    @EventHandler
    public void onInventoryClick(InventoryClickEvent event)
    {
        if ( event.getSlotType().equals( InventoryType.SlotType.ARMOR ) )
        {
            event.setCancelled( true );
        }
    }

    public enum Slot
    {
        HELD( 36, 44 ), BOOTS( 8, 8 ), LEGGINGS( 7, 7 ), CHEST_PLATE( 6, 6 ), HELMET( 5, 5 );


        private int min;
        private int max;

        Slot(int min, int max)
        {
            this.min = min;
            this.max = max;
        }

        public int getMin()
        {
            return min;
        }

        public int getMax()
        {
            return max;
        }

        public static Slot getBySlot(int slot)
        {
            for ( Slot enumSlot : values() )
            {
                if ( enumSlot.getMin() >= slot && enumSlot.getMax() <= slot )
                {
                    System.out.println( enumSlot );
                    return enumSlot;
                }
            }
            return null;
        }
    }
}