package com.gmail.filoghost.uuidfix;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.UUID;
import java.util.logging.Level;

import net.minecraft.util.com.mojang.authlib.GameProfile;

import org.bukkit.Bukkit;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerLoginEvent;
import org.bukkit.event.player.PlayerLoginEvent.Result;
import org.bukkit.plugin.java.JavaPlugin;

import com.google.common.base.Charsets;

public class UUIDFix extends JavaPlugin implements Listener {

    private String nmsRoot;
    private String craftbukkitRoot;

    private Class<?> entityHumanClass;
    private Class<?> entityClass;
    private Class<?> craftPlayerClass;

    private Method getHandleMethod;

    private Field gameProfileField;
    private Field idField;
    private Field uniqueIDField;

    @Override
    public void onEnable() {

        try {
            String craftServer = Bukkit.getServer().getClass().getName();
            String craftRoot = craftServer.substring(0, craftServer.lastIndexOf('.'));
            String nmsVersion = craftRoot.substring(craftRoot.lastIndexOf('.') + 1);

            nmsRoot = "net.minecraft.server." + nmsVersion;
            craftbukkitRoot = "org.bukkit.craftbukkit." + nmsVersion;

            entityHumanClass = Class.forName(nmsRoot + ".EntityHuman");
            entityClass = Class.forName(nmsRoot + ".Entity");
            craftPlayerClass = Class.forName(craftbukkitRoot + ".entity.CraftPlayer");

            getHandleMethod = craftPlayerClass.getDeclaredMethod("getHandle");

            gameProfileField = findFieldByClass(entityHumanClass, GameProfile.class);
            removeFinalModifier(gameProfileField);
            gameProfileField.setAccessible(true);

            idField = findFieldByClass(GameProfile.class, UUID.class);
            removeFinalModifier(idField);
            idField.setAccessible(true);

            uniqueIDField = findFieldByClass(entityClass, UUID.class);
            removeFinalModifier(uniqueIDField);
            uniqueIDField.setAccessible(true);

        } catch (Exception ex) {
            getLogger().log(Level.WARNING, "Error loading with reflection", ex);
        }

        Bukkit.getPluginManager().registerEvents(this, this);
    }


    @EventHandler
    public void onLogin(PlayerLoginEvent event) {
        Player player = event.getPlayer();

        if (player.getName().equals(player.getName().toLowerCase())) {
            // Non ha bisogno di essere sistemato
            return;
        }

        System.out.println("Before: " + player.getUniqueId());

        try {

            UUID fixedId = UUID.nameUUIDFromBytes(("OfflinePlayer:" + player.getName().toLowerCase()).getBytes(Charsets.UTF_8));
            Object nmsPlayer = getHandleMethod.invoke(player);
            Object gameProfile = gameProfileField.get(nmsPlayer);

            idField.set(gameProfile, fixedId);
            uniqueIDField.set(nmsPlayer, fixedId);

        } catch (Exception e) {

            event.disallow(Result.KICK_OTHER, "Errore interno, per favore contatta lo staff.");
            e.printStackTrace();
        }

        System.out.println("After: " + player.getUniqueId());
    }

    private Field findFieldByClass(Class<?> source, Class<?> fieldClass) {
        for (Field field : source.getDeclaredFields()) {
            if (field.getType() == fieldClass) {
                return field;
            }
        }

        return null;
    }

    private static void removeFinalModifier(Field field) throws Exception {
        Field fieldModifiers = Field.class.getDeclaredField("modifiers");
        fieldModifiers.setAccessible(true);
        fieldModifiers.setInt(field, field.getModifiers() & ~Modifier.FINAL);
    }
}