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<?php

/**
 * MvcCore
 *
 * This source file is subject to the BSD 3 License
 * For the full copyright and license information, please view
 * the LICENSE.md file that are distributed with this source code.
 *
 * @copyright   Copyright (c) 2016 Tom Flidr (https://github.com/mvccore)
 * @license     https://mvccore.github.io/docs/mvccore/5.0.0/LICENCE.md
 */

namespace MvcCore\Ext\Views\Helpers;

/**
 * Responsibility - better view helper setup.
 * - Every time, when there is necessary to create view helper, there is called
 *   `\MvcCore\Ext\Views\Helpers\IHelper::GetInstance();` method in `\MvcCore\View`.
 *   All view helpers are stored inside `\MvcCore\View` and they are created only once.
 *   But if you need to configure view helper anytime before, you can use this method
 *   for singleton instancing to configure anything statically anytime before.
 * - Every time, when currently rendered view object is changed (action view, layout view,
 *   sub-controller view...), there is called `\MvcCore\Ext\Views\Helpers\IHelper::SetView($view);`
 *   method giving currently rendered view object. From this object, you can get properties
 *   for better view helper processing like application object, controller, request or response object.
 * @method \MvcCore\Ext\Views\Helpers\AbstractHelper GetInstance()
 */
abstract class AbstractHelper implements \MvcCore\Ext\Views\Helpers\IHelper {

    /**
     * MvcCore Extension - View Helper - Line Breaks - version:
     * Comparison by PHP function version_compare();
     * @see http://php.net/manual/en/function.version-compare.php
     */
    const VERSION = '5.0.0';

    /**
     * Instance store used by method `GetInstance()`.
     * @var \MvcCore\Ext\Views\Helpers\AbstractHelper|NULL
     */
    protected static $instance = NULL;

    /**
     * Currently rendered view instance reference.
     * Every time, when there is rendered different view script,
     * this view property is changed by method `\MvcCore\Ext\Views\Helpers\AbstractHelper::SetView();`.
     * @var \MvcCore\View
     */
    protected $view = NULL;

    /**
     * Currently used controller instance reference for currently rendered view script.
     * Every time, when there is rendered different view script,
     * this controller and also view property is changed by method `\MvcCore\Ext\Views\Helpers\AbstractHelper::SetView();`.
     * @var \MvcCore\Controller
     */
    protected $controller = NULL;

    /**
     * Current request object reference from used controller.
     * @var \MvcCore\Request
     */
    protected $request = NULL;

    /**
     * Current response object reference from used controller.
     * @var \MvcCore\Response
     */
    protected $response = NULL;

    /**
     * Create view helper instance as singleton.
     * To configure view helper instance, create it by this method
     * in your base controller in `PreDispatch();` method.
     * After this singleton instance is created, then you can configure
     * anything you want.
     *
     * Example:
     *  // somewhere in base controller:
     *  `\MvcCore\Ext\Views\Helpers\LineBreaks::GetInstance()
     *      ->SetView($this->view)
     *      ->SetAnythingElseBeforeRendering(...);`
     * @static
     * @return \MvcCore\Ext\Views\Helpers\AbstractHelper
     */
    public static function GetInstance () {
        if (!static::$instance) static::$instance = new static();
        return static::$instance;
    }

    /**
     * Set currently rendered view instance every time this helper
     * is called and the rendered view instance is changed.
     * This method sets these protected object references:
     * - `AbstractHelper::$view` as `\MvcCore\View|\MvcCore\IView`
     * - `AbstractHelper::$controller` as `\MvcCore\Controller|\MvcCore\IController`
     * - `AbstractHelper::$request` as `\MvcCore\Request|\MvcCore\IRequest`
     * - `AbstractHelper::$response` as `\MvcCore\Response|\MvcCore\IResponse`
     * @param \MvcCore\View $view
     * @return \MvcCore\Ext\Views\Helpers\AbstractHelper
     */
    public function SetView (\MvcCore\IView $view) {
        $this->view = $view;
        $this->controller = $view->GetController();
        $this->request = $this->controller->GetRequest();
        $this->response = $this->controller->GetResponse();
        return $this;
    }
}