Core/src/eu/univento/core/api/utils/reflection/Reflection.java

package eu.univento.core.api.utils.reflection;

import org.bukkit.Bukkit;
import org.bukkit.entity.Entity;
import org.bukkit.entity.Player;
import org.bukkit.inventory.ItemStack;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class Reflection
{
  public static final Class<?> CLASS_CRAFTITEMSTACK = getCraftBukkitClass("inventory.CraftItemStack");
  public static final Method METHOD_ASNMSCOPY = getMethod(CLASS_CRAFTITEMSTACK, "asNMSCopy");

  public static void sendPacket(Player p, Object packet) {
    try {
      Object nmsPlayer = getNMSPlayer(p);
      Object connection = nmsPlayer.getClass()
        .getField("playerConnection").get(nmsPlayer);
      connection.getClass()
        .getMethod("sendPacket", new Class[] { getNMSClass("Packet") })
        .invoke(connection, new Object[] { packet });
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  public static Field getField(Class<?> clazz, String field) {
    Field re = null;
    try {
      re = clazz.getDeclaredField(field);
    } catch (NoSuchFieldException e) {
      e.printStackTrace();
    } catch (SecurityException e) {
      e.printStackTrace();
    }
    return re;
  }

  public static void sendPacket(Player p, String packetName, Class<?>[] parameterclass, Object[] parameters) {
    try {
      Object nmsPlayer = getNMSPlayer(p);
      Object connection = nmsPlayer.getClass()
        .getField("playerConnection").get(nmsPlayer);
      Object packet = 
        Class.forName(
        nmsPlayer.getClass().getPackage().getName() + "." + 
        packetName)
        .getConstructor(parameterclass).newInstance(parameters);
      connection.getClass()
        .getMethod("sendPacket", new Class[] { getNMSClass("Packet") })
        .invoke(connection, new Object[] { packet });
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  public static String getVersion() {
    String name = Bukkit.getServer().getClass().getPackage().getName();
    String version = name.substring(name.lastIndexOf('.') + 1) + ".";
    return version;
  }

  public static Class<?> getNMSClass(String className) {
    String fullName = "net.minecraft.server." + getVersion() + className;
    Class<?> clazz = null;
    try {
      clazz = Class.forName(fullName);
    } catch (Exception e) {
      e.printStackTrace();
    }
    return clazz;
  }
  public static Class<?> getCraftBukkitClass(String className) {
    String fullName = "org.bukkit.craftbukkit." + getVersion() + className;
    Class<?> clazz = null;
    try {
      clazz = Class.forName(fullName);
    } catch (Exception e) {
      e.printStackTrace();
    }
    return clazz;
  }

  public static Object asNMSCopy(ItemStack i) throws IllegalAccessException, InvocationTargetException {
    Object re = null;
    try
    {
      METHOD_ASNMSCOPY.invoke(null, new Object[] { i });
    }
    catch (java.lang.IllegalArgumentException e) {
      e.printStackTrace();
    }

    return re;
  }

  public static Field getField(Field f) {
    f.setAccessible(true);
    return f;
  }
  public static Constructor<?> getConstructor(Class<?> clazz, Class<?>[] param) {
    Constructor<?> re = null;
    try {
      re = clazz.getConstructor(param);
    } catch (Exception e) {
      e.printStackTrace();
    }
    return re;
  }
  public static Object getHandle(Entity entity) {
    Object object = null;
    try
    {
      object = getMethod(entity.getClass(), "getHandle").invoke(entity, new Object[0]);
    } catch (Exception e) {
      e.printStackTrace();
    }

    return object;
  }

  public static Object getNMSPlayer(Player player) {
    return getHandle(player);
  }

  public static Method getMethod(Class<?> c, String methodName) {
    Method returnMethod = null;

    for (Method m : c.getDeclaredMethods()) {
      if (m.getName().equals(methodName)) {
        returnMethod = m;
      }
    }

    return returnMethod;
  }
}