<?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_Filter
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: PregReplace.php 8064 2008-02-16 10:58:39Z thomas $
 */

/**
 * @see Zend_Filter_Interface
 */
require_once 'Zend/Filter/Interface.php';

/**
 * @category   Zend
 * @package    Zend_Filter
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Filter_PregReplace implements Zend_Filter_Interface
{
    /**
     * Pattern to match
     * @var mixed
     */
    protected $_matchPattern = null;

    /**
     * Replacement pattern
     * @var mixed
     */
    protected $_replacement = '';
    
    /**
     * Is unicode enabled?
     *
     * @var bool
     */
    static protected $_unicodeSupportEnabled = null;

    /**
     * Is Unicode Support Enabled Utility function
     *
     * @return bool
     */
    static public function isUnicodeSupportEnabled()
    {
        if (self::$_unicodeSupportEnabled === null) {
            self::_determineUnicodeSupport();
        }
        
        return self::$_unicodeSupportEnabled;
    }
    
    /**
     * Method to cache the regex needed to determine if unicode support is available
     *
     * @return bool
     */
    static protected function _determineUnicodeSupport()
    {
        self::$_unicodeSupportEnabled = (@preg_match('/\pL/u', 'a')) ? true : false;
    }
    
    /**
     * Constructor
     * 
     * @param  string $match 
     * @param  string $replace 
     * @return void
     */
    public function __construct($matchPattern = null, $replacement = null)
    {
        if ($matchPattern) {
            $this->setMatchPattern($matchPattern);
        }
        
        if ($replacement) {
            $this->setReplacement($replacement);
        }
    }
    
    /**
     * Set the match pattern for the regex being called within filter()
     *
     * @param mixed $match - same as the first argument of preg_replace
     * @return Zend_Filter_PregReplace
     */
    public function setMatchPattern($match)
    {
        $this->_matchPattern = $match;
        return $this;
    }

    /**
     * Get currently set match pattern
     * 
     * @return string
     */
    public function getMatchPattern()
    {
        return $this->_matchPattern;
    }
    
    /**
     * Set the Replacement pattern/string for the preg_replace called in filter
     *
     * @param mixed $replacement - same as the second argument of preg_replace
     * @return Zend_Filter_PregReplace
     */
    public function setReplacement($replacement)
    {
        $this->_replacement = $replacement;
        return $this;
    }

    /**
     * Get currently set replacement value
     * 
     * @return string
     */
    public function getReplacement()
    {
        return $this->_replacement;
    }
    
    /**
     * Perform regexp replacement as filter
     * 
     * @param  string $value 
     * @return string
     */
    public function filter($value)
    {
        if ($this->_matchPattern == null) {
            require_once 'Zend/Filter/Exception.php';
            throw new Zend_Filter_Exception(get_class($this) . ' does not have a valid MatchPattern set.');
        }
        
        return preg_replace($this->_matchPattern, $this->_replacement, $value);    
    }
    
}
