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/*
 * Copyright (C) SainttX 
 * Copyright (C) contributors
 *
 * This file is part of Auctions.
 *
 * Auctions is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Auctions 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Auctions.  If not, see .
 */
package cat.nyaa.nyaacore.utils;

import org.bukkit.Bukkit;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.*;

public final class ReflectionUtils {

    /*
     * Cache of NMS classes that we've searched for
     */
    private static final Map> loadedNMSClasses = new HashMap<>();
    /*
     * Cache of OBS classes that we've searched for
     */
    private static final Map> loadedOBCClasses = new HashMap<>();
    /*
     * Cache of methods that we've found in particular classes
     */
    private static final Map, Map> loadedMethods = new HashMap<>();
    /*
     * The server version string to location NMS & OBC classes
     */
    private static String versionString;

    /**
     * Gets the version string for NMS & OBC class paths
     *
     * @return The version string of OBC and NMS packages
     */
    public static String getVersion() {
        if (versionString == null) {
            String name = Bukkit.getServer().getClass().getPackage().getName();
            versionString = name.substring(name.lastIndexOf('.') + 1) + ".";
        }

        return versionString;
    }

    /**
     * Get a class from the org.bukkit.craftbukkit package
     *
     * @param obcClassName the path to the class
     * @return the found class at the specified path
     */
    public static Class getOBCClass(String obcClassName) {
        if (loadedOBCClasses.containsKey(obcClassName)) {
            return loadedOBCClasses.get(obcClassName);
        }

        String clazzName = "org.bukkit.craftbukkit." + getVersion() + obcClassName;
        Class clazz;

        try {
            clazz = Class.forName(clazzName);
        } catch (Throwable t) {
            t.printStackTrace();
            loadedOBCClasses.put(obcClassName, null);
            return null;
        }

        loadedOBCClasses.put(obcClassName, clazz);
        return clazz;
    }

    /**
     * Get a method from a class that has the specific parameters
     *
     * @param clazz      The class we are searching
     * @param methodName The name of the method
     * @param params     Any parameters that the method has
     * @return The method with appropriate parameters
     */
    public static Method getMethod(Class clazz, String methodName, Class... params) {
        if (!loadedMethods.containsKey(clazz)) {
            loadedMethods.put(clazz, new HashMap<>());
        }

        Map methods = loadedMethods.get(clazz);

        if (methods.containsKey(methodName)) {
            return methods.get(methodName);
        }

        try {
            Method method = clazz.getDeclaredMethod(methodName, params);
            if (method != null) method.setAccessible(true);
            methods.put(methodName, method);
            loadedMethods.put(clazz, methods);
            return method;
        } catch (Exception e) {
            e.printStackTrace();
            methods.put(methodName, null);
            loadedMethods.put(clazz, methods);
            return null;
        }
    }


    /**
     * get all declared fields in a class and its' super class.
     *
     * @param clz target class
     * @return a List of Field objects declared by clz.
     * @since 7.2
     */
    public static List getAllFields(Class clz) {
        List fields = new ArrayList<>();
        return getAllFields(clz, fields);
    }

    private static List getAllFields(Class clz, List list) {
        Collections.addAll(list, clz.getDeclaredFields());

        Class supClz = clz.getSuperclass();
        if (supClz == null) {
            return list;
        } else {
            return getAllFields(supClz, list);
        }
    }
}