package com.itsoku.lambda;

/*
 * Copyright (c) 2011-2020, baomidou (jobob@qq.com).
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * <p>
 * https://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

import org.springframework.util.Assert;

import java.util.Arrays;
import java.util.List;

final class ClassUtils {

    private static final char PACKAGE_SEPARATOR = '.';

    /**
     * 代理 class 的名称
     */
    private static final List<String> PROXY_CLASS_NAMES = Arrays.asList("net.sf.cglib.proxy.factory"
            // cglib
            , "org.springframework.cglib.proxy.factory"
            , "javassist.util.proxy.ProxyObject"
            // javassist
            , "org.apache.ibatis.javassist.util.proxy.ProxyObject");

    private ClassUtils() {
    }

    /**
     * <p>
     * 判断是否为代理对象
     * </p>
     *
     * @param clazz 传入 class 对象
     * @return 如果对象class是代理 class，返回 true
     */
    public static boolean isProxy(Class<?> clazz) {
        if (clazz != null) {
            for (Class<?> cls : clazz.getInterfaces()) {
                if (PROXY_CLASS_NAMES.contains(cls.getName())) {
                    return true;
                }
            }
        }
        return false;
    }

    /**
     * <p>
     * 获取当前对象的 class
     * </p>
     *
     * @param clazz 传入
     * @return 如果是代理的class，返回父 class，否则返回自身
     */
    public static Class<?> getUserClass(Class<?> clazz) {
        return isProxy(clazz) ? clazz.getSuperclass() : clazz;
    }

    /**
     * <p>
     * 获取当前对象的class
     * </p>
     *
     * @param object 对象
     * @return 返回对象的 user class
     */
    public static Class<?> getUserClass(Object object) {
        Assert.notNull(object, "Error: Instance must not be null");
        return getUserClass(object.getClass());
    }


    /**
     * <p>
     * 请仅在确定类存在的情况下调用该方法
     * </p>
     *
     * @param name 类名称
     * @return 返回转换后的 Class
     */
    public static Class<?> toClassConfident(String name) {
        try {
            return Class.forName(name);
        } catch (ClassNotFoundException e) {
            throw new LambdaParseException("找不到指定的class！请仅在明确确定会有 class 的时候，调用该方法", e);
        }
    }


    /**
     * Determine the name of the package of the given class,
     * e.g. "java.lang" for the {@code java.lang.String} class.
     *
     * @param clazz the class
     * @return the package name, or the empty String if the class
     * is defined in the default package
     */
    public static String getPackageName(Class<?> clazz) {
        Assert.notNull(clazz, "Class must not be null");
        return getPackageName(clazz.getName());
    }

    /**
     * Determine the name of the package of the given fully-qualified class name,
     * e.g. "java.lang" for the {@code java.lang.String} class name.
     *
     * @param fqClassName the fully-qualified class name
     * @return the package name, or the empty String if the class
     * is defined in the default package
     */
    public static String getPackageName(String fqClassName) {
        Assert.notNull(fqClassName, "Class name must not be null");
        int lastDotIndex = fqClassName.lastIndexOf(PACKAGE_SEPARATOR);
        return (lastDotIndex != -1 ? fqClassName.substring(0, lastDotIndex) : "");
    }
}