<?php

namespace Heku\Library;

/**
 * @package     Heku\Library
 * @subpackage  Classes/LibraryLoader
 * @author      Heku Daleconan <http://www.daleconan.com>
 * @copyright   Copyright (c) 2022-2023, Heku Daleconan
 * @license     http://opensource.org/licenses/gpl-2.0.php GNU Public License
 */

class LibraryLoader {

    /** 
     * 类实现单例模式，类的独生子女
     */
    private static $instance;

    /**
     * 依赖注入的接口 Instance 方法
     * 目标是 保证 init（） 初始化方法 只执行一次
     *
     * @return self  唯一实例化的本类
     */
    public static function instance() {
        if ( ! isset( self::$instance ) ) {
            self::$instance = new self;
            self::$instance->init();
        }
        return self::$instance;
    }

    private function init() {

        $is_admin = is_admin() || $GLOBALS['pagenow'] === 'wp-login.php';

        if( is_admin() ){
            //加载 Cmb2 插件 及其附属扩展组件
            require_once HEKU_THEME_DIR . HK_DS . 'Library' . HK_DS . 'Cmb2' . HK_DS .'init.php';
            require_once HEKU_THEME_DIR . HK_DS . 'Library' . HK_DS . 'cmb2-attached-posts-master' . HK_DS . 'cmb2-attached-posts-field.php';
            require_once HEKU_THEME_DIR . HK_DS . 'Library' . HK_DS . 'cmb2-field-select2' . HK_DS . 'cmb-field-select2.php';
            require_once HEKU_THEME_DIR . HK_DS . 'Library' . HK_DS . 'cmb2-nav-menu' . HK_DS . 'cmb2-nav-menus.php';
            require_once HEKU_THEME_DIR . HK_DS . 'Library' . HK_DS . 'cmb2-page-select-master' . HK_DS . 'cmb2_page_select.php';
            require_once HEKU_THEME_DIR . HK_DS . 'Library' . HK_DS . 'cmb2-term-select' . HK_DS . 'cmb2-term-select.php';
        }

    }

}