<?php

/**

 * Zend Framework

 *

 * LICENSE

 *

 * This source file is subject to the new BSD license that is bundled

 * with this package in the file LICENSE.txt.

 * It is also available through the world-wide-web at this URL:

 * http://framework.zend.com/license/new-bsd

 * If you did not receive a copy of the license and are unable to

 * obtain it through the world-wide-web, please send an email

 * to license@zend.com so we can send you a copy immediately.

 *

 * @category   Zend

 * @package    Zend_Form

 * @subpackage Decorator

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 */

/** Zend_Form_Decorator_Abstract */

require_once 'Zend/Form/Decorator/Abstract.php';

/**

 * Zend_Form_Decorator_Callback

 *

 * Execute an arbitrary callback to decorate an element. Callbacks should take

 * three arguments, $content, $element, and $options:

 *

 * function mycallback($content, $element, array $options)

 * {

 * }

 *

 * and should return a string. ($options are whatever options were provided to

 * the decorator.)

 *

 * To specify a callback, pass a valid callback as the 'callback' option.

 *

 * Callback results will be either appended, prepended, or replace the provided

 * content. To replace the content, specify a placement of boolean false;

 * defaults to append content.

 *

 * @category   Zend

 * @package    Zend_Form

 * @subpackage Decorator

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 * @version    $Id: Callback.php 20096 2010-01-06 02:05:09Z bkarwin $

 */

class Zend_Form_Decorator_Callback extends Zend_Form_Decorator_Abstract

{

    /**

     * Callback

     * @var string|array

     */

    protected $_callback;

    /**

     * Set callback

     *

     * @param  callback $callback

     * @return Zend_Form_Decorator_Callback

     * @throws Zend_Form_Exception

     */

    public function setCallback($callback)

    {

        if (!is_callable($callback)) {

            require_once 'Zend/Form/Exception.php';

            throw new Zend_Form_Exception('Invalid callback provided to callback decorator');

        }

        $this->_callback = $callback;

        return $this;

    }

    /**

     * Get registered callback

     *

     * If not previously registered, checks to see if it exists in registered

     * options.

     *

     * @return null|string|array

     */

    public function getCallback()

    {

        if (null === $this->_callback) {

            if (null !== ($callback = $this->getOption('callback'))) {

                $this->setCallback($callback);

                $this->removeOption('callback');

            }

        }

        return $this->_callback;

    }

    /**

     * Render

     *

     * If no callback registered, returns callback. Otherwise, gets return

     * value of callback and either appends, prepends, or replaces passed in

     * content.

     *

     * @param  string $content

     * @return string

     */

    public function render($content)

    {

        $callback = $this->getCallback();

        if (null === $callback) {

            return $content;

        }

        $placement = $this->getPlacement();

        $separator = $this->getSeparator();

        $response = call_user_func($callback, $content, $this->getElement(), $this->getOptions());

        switch ($placement) {

            case self::APPEND:

                return $content . $separator . $response;

            case self::PREPEND:

                return $response . $separator . $content;

            default:

                // replace content

                return $response;

        }

    }

}