<?php
/**
 * Magento
 *
 * NOTICE OF LICENSE
 *
 * This source file is subject to the Open Software License (OSL 3.0)
 * that is bundled with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://opensource.org/licenses/osl-3.0.php
 * 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@magentocommerce.com so we can send you a copy immediately.
 *
 * DISCLAIMER
 *
 * Do not edit or add to this file if you wish to upgrade Magento to newer
 * versions in the future. If you wish to customize Magento for your
 * needs please refer to http://www.magentocommerce.com for more information.
 *
 * @category    Mage
 * @package     Mage_CatalogRule
 * @copyright   Copyright (c) 2012 Magento Inc. (http://www.magentocommerce.com)
 * @license     http://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
 */

/**
 * CatalogRule data helper
 */
class Mage_CatalogRule_Helper_Data extends Mage_Core_Helper_Abstract
{
    /**
     * Algorithm for calculating price rule
     *
     * @param  string $actionOperator
     * @param  int $ruleAmount
     * @param  float $price
     * @return float|int
     */
    public function calcPriceRule($actionOperator, $ruleAmount, $price)
    {
        $priceRule = 0;
        switch ($actionOperator) {
            case 'to_fixed':
                $priceRule = min($ruleAmount, $price);
                break;
            case 'to_percent':
                $priceRule = $price * $ruleAmount / 100;
                break;
            case 'by_fixed':
                $priceRule = max(0, $price - $ruleAmount);
                break;
            case 'by_percent':
                $priceRule = $price * (1 - $ruleAmount / 100);
                break;
        }
        return $priceRule;
    }
}
