[Packets Bukkit] BossBar API [Protocolib]

package au.com.addstar.pandora;

import java.lang.reflect.InvocationTargetException;
import java.util.WeakHashMap;

import org.apache.commons.lang.Validate;
import org.bukkit.Bukkit;
import org.bukkit.Location;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.EventPriority;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerMoveEvent;
import org.bukkit.plugin.Plugin;

import com.comphenix.protocol.PacketType;
import com.comphenix.protocol.ProtocolLibrary;
import com.comphenix.protocol.ProtocolManager;
import com.comphenix.protocol.events.PacketContainer;
import com.comphenix.protocol.wrappers.WrappedDataWatcher;

public class DisplayManager
{
    private static final int ENTITY_DRAGON_ID = 999999999;

    private static WeakHashMap<Player, DisplayManager> mAllManagers = new WeakHashMap<Player, DisplayManager>();
    private static ProtocolManager mLib;

    private Player mPlayer;
    private Location mLocation;

    private boolean mShowBossBar;
    private String mCurrentBossText;
    private float mCurrentBossValue;

    private DisplayManager(Player player)
    {
        mPlayer = player;
        mLocation = mPlayer.getLocation();
        mShowBossBar = false;
    }

    public void updateDisplays()
    {
        Location loc = mPlayer.getLocation();

        if(mShowBossBar)
        {
            if(mLocation.getWorld() != loc.getWorld())
            {
                int value = (int)Math.min(Math.max(mCurrentBossValue * 200, 0), 200);
                spawnFakeDragon(mCurrentBossText, value);
            }
            else
            {
                double dist = mLocation.distanceSquared(loc);

                if(dist >= 640000)
                {
                    int value = (int)Math.min(Math.max(mCurrentBossValue * 200, 0), 200);
                    spawnFakeDragon(mCurrentBossText, value);
                    mLocation = loc;
                }
                else if(dist > 500)
                {
                    positionDragon();
                    mLocation = loc;
                }
            }
        }
    }

    public void displayBossBar(String text, float percent)
    {
        mCurrentBossText = text;
        mCurrentBossValue = percent;
        int value = (int)Math.min(Math.max(percent * 200, 0), 200);

        if(mShowBossBar)
            spawnFakeDragon(text, value);
        else
            updateDragonStats(text, value);

        mShowBossBar = true;
    }

    public void hideBossBar()
    {
        if(!mShowBossBar)
            return;

        mShowBossBar = false;
        removeDragon();
    }

    private void spawnFakeDragon(String name, int health)
    {
        Location loc = mPlayer.getLocation();

        PacketContainer spawnPacket = mLib.createPacket(PacketType.Play.Server.SPAWN_ENTITY_LIVING);
        spawnPacket.getIntegers().write(0, ENTITY_DRAGON_ID); // EntityId
        spawnPacket.getIntegers().write(1, 63); // EntityType
        spawnPacket.getIntegers().write(2, loc.getBlockX() * 32); // X
        spawnPacket.getIntegers().write(3, -500 * 32); // Y
        spawnPacket.getIntegers().write(4, loc.getBlockZ() * 32); // Z
        spawnPacket.getBytes().write(0, (byte)0); // Yaw
        spawnPacket.getBytes().write(1, (byte)0); // Pitch
        spawnPacket.getBytes().write(2, (byte)0); // ? head?

        spawnPacket.getIntegers().write(5, 0); // MotX
        spawnPacket.getIntegers().write(6, 0); // MotY
        spawnPacket.getIntegers().write(7, 0); // MotZ

        WrappedDataWatcher wrapper = new WrappedDataWatcher();

        if(name.length() > 64)
            name = name.substring(0,64);
        wrapper.setObject(0, (byte)0x20);
        wrapper.setObject(6, Float.valueOf(health));
        wrapper.setObject(10, name);
        wrapper.setObject(11, Byte.valueOf((byte)1));

        spawnPacket.getDataWatcherModifier().write(0, wrapper); // DataWatcher

        try
        {
            mLib.sendServerPacket(mPlayer, spawnPacket, false);
        }
        catch ( InvocationTargetException e )
        {
            e.printStackTrace();
        }
    }

    private void updateDragonStats(String name, int health)
    {
        PacketContainer update = mLib.createPacket(PacketType.Play.Server.ENTITY_METADATA);
        update.getIntegers().write(0, ENTITY_DRAGON_ID); // EntityId

        WrappedDataWatcher wrapper = new WrappedDataWatcher();

        if(name.length() > 64)
            name = name.substring(0,64);
        wrapper.setObject(0, (byte)0x20);
        wrapper.setObject(6, Float.valueOf(health));
        wrapper.setObject(10, name);
        wrapper.setObject(11, Byte.valueOf((byte)1));

        update.getWatchableCollectionModifier().write(0, wrapper.getWatchableObjects()); // DataWatcher

        try
        {
            mLib.sendServerPacket(mPlayer, update, false);
        }
        catch ( InvocationTargetException e )
        {
            e.printStackTrace();
        }
    }

    private void positionDragon()
    {
        Location loc = mPlayer.getLocation();

        PacketContainer movePacket = mLib.createPacket(PacketType.Play.Server.ENTITY_TELEPORT);
        movePacket.getIntegers().write(0, ENTITY_DRAGON_ID); // EntityId
        movePacket.getIntegers().write(1, loc.getBlockX() * 32); // X
        movePacket.getIntegers().write(2, -500 * 32); // Y
        movePacket.getIntegers().write(3, loc.getBlockZ() * 32); // Z
        movePacket.getBytes().write(0, (byte)0); // Yaw
        movePacket.getBytes().write(1, (byte)0); // Pitch


        try
        {
            mLib.sendServerPacket(mPlayer, movePacket, false);
        }
        catch ( InvocationTargetException e )
        {
            e.printStackTrace();
        }
    }

    private void removeDragon()
    {
        PacketContainer deletePacket = mLib.createPacket(PacketType.Play.Server.ENTITY_DESTROY);
        deletePacket.getIntegerArrays().write(0, new int[] {ENTITY_DRAGON_ID});

        try
        {
            mLib.sendServerPacket(mPlayer, deletePacket, false);
        }
        catch ( InvocationTargetException e )
        {
            e.printStackTrace();
        }
    }

    public static void initialize(Plugin plugin)
    {
        Validate.isTrue(mLib == null);

        mLib = ProtocolLibrary.getProtocolManager();

        Bukkit.getPluginManager().registerEvents(new DisplayListener(), plugin);
    }

    public static DisplayManager getDisplayManager(Player player)
    {
        DisplayManager manager = mAllManagers.get(player);
        if(manager == null)
        {
            manager = new DisplayManager(player);
            mAllManagers.put(player, manager);
        }

        return manager;
    }

    private static class DisplayListener implements Listener
    {
        @EventHandler(priority=EventPriority.MONITOR, ignoreCancelled=true)
        private void onPlayerMove(PlayerMoveEvent event)
        {
            DisplayManager manager = mAllManagers.get(event.getPlayer());
            if(manager != null)
                manager.updateDisplays();
        }
    }
}