<?php

/**
 * @file classes/core/PKPServices.php
 *
 * Copyright (c) 2014-2021 Simon Fraser University
 * Copyright (c) 2000-2021 John Willinsky
 * Distributed under the GNU GPL v3. For full terms see the file docs/COPYING.
 *
 * @class PKPServices
 *
 * @ingroup core
 *
 * @see Core
 *
 * @brief Pimple Dependency Injection Container.
 */

namespace PKP\core;

use APP\core\Services;
use Pimple\Container;

abstract class PKPServices
{
    /** @var Container Pimple Dependency Injection Container */
    private static $instance = null;

    protected $container = null;

    /**
     * private constructor
     */
    private function __construct()
    {
        $this->container = new Container();
        $this->init();
    }

    /**
     * container initialization
     */
    abstract protected function init();

    /**
     * A static method to register a service
     */
    public static function register(\Pimple\ServiceProviderInterface $service)
    {
        self::_instance()->container->register($service);
    }

    /**
     * A static method to get a service
     *
     * @param string $service
     */
    public static function get($service)
    {
        return self::_instance()->_getFromContainer($service);
    }

    /**
     * Returns the instance of the container
     *
     * @return static
     */
    private static function _instance()
    {
        if (is_null(self::$instance)) {
            self::$instance = new Services();
        }

        return self::$instance;
    }

    /**
     * Gets the service from an instanced container.
     *
     * @param string $service
     */
    private function _getFromContainer($service)
    {
        return $this->container[$service];
    }
}

if (!PKP_STRICT_MODE) {
    class_alias('\PKP\core\PKPServices', '\PKPServices');
}