<?php

/*

 * Enano - an open-source CMS capable of wiki functions, Drupal-like sidebar blocks, and everything in between

 * Copyright (C) 2006-2009 Dan Fuhry

 * captcha.php - visual confirmation system used during registration

 *

 * This program is Free Software; you can redistribute and/or modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied

 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for details.

 */

/**

 * The base class for CAPTCHA engines.

 * @package Enano

 * @subpackage User management

 * @copyright 2008 Dan Fuhry

 */

class captcha_base

{

	/**

 	* Our session ID

 	* @var string

 	*/

	private $session_id;

	/**

 	* Our saved session data

 	* @var array

 	*/

	private $session_data;

	/**

 	* The confirmation code we're generating.

 	* @var string

 	*/

	private $code = '';

	/**

 	* Numerical ID (primary key) for our session

 	* @var int

 	*/

	private $id = 0;

	/**

 	* Constructor.

 	* @param string Session ID for captcha

 	*/

	function __construct($session_id, $row = false)

	{

		global $db, $session, $paths, $template, $plugins; // Common objects

		if ( !preg_match('/^[a-f0-9]{32}([a-z0-9]{8})?$/', $session_id) )

		{

			throw new Exception('Invalid session ID');

		}

		$this->session_id = $session_id;

		// If we weren't supplied with session info, retreive it

		if ( !is_array($row) )

		{

			$q = $db->sql_query('SELECT code_id, code, session_data FROM ' . table_prefix . "captcha WHERE session_id = '$session_id';");

			if ( !$q )

				$db->_die();

			$row = $db->fetchrow();

			$row['code_id'] = intval($row['code_id']);

			$db->free_result();

		}

		if ( !isset($row['code']) || !isset($row['session_data']) || !is_int(@$row['code_id']) )

		{

			throw new Exception('Row doesn\'t contain what we need (code and session_data)');

		}

		$this->session_data = ( is_array($x = @unserialize($row['session_data'])) ) ? $x : array();

		$this->code = $row['code'];

		$this->id = $row['code_id'];

		// run any custom init functions

		if ( method_exists($this, 'construct_hook') )

			$this->construct_hook();

	}

	/**

 	* Retrieves a key from the session data set

 	* @param int|string Key to fetch

 	* @param mixed Default value for key

 	* @return mixed

 	*/

	function session_fetch($key, $default = false)

	{

		return ( isset($this->session_data[$key]) ) ? $this->session_data[$key] : $default;

	}

	/**

 	* Stores a value in the session's data set. Change must be committed using $captcha->session_commit()

 	* @param int|string Name of key

 	* @param mixed Value - can be an array, string, int, or double, but probably not objects :-)

 	*/

	function session_store($key, $value)

	{

		$this->session_data[$key] = $value;

	}

	/**

 	* Commits changes to the session data set to the database.

 	*/

	function session_commit()

	{

		global $db, $session, $paths, $template, $plugins; // Common objects

		$session_data = serialize($this->session_data);

		$session_data = $db->escape($session_data);

		$code = $db->escape($this->code);

		$q = $db->sql_query('UPDATE ' . table_prefix . "captcha SET code = '$code', session_data = '$session_data' WHERE code_id = {$this->id};");

		if ( !$q )

			$db->_die();

	}

	/**

 	* Changes the confirmation code

 	* @param string New string

 	*/

	function set_code($code)

	{

		if ( !is_string($code) )

			return false;

		$this->code = $code;

	}

	/**

 	* Returns the confirmation code

 	* @return string

 	*/

	function get_code()

	{

		return $this->code;

	}

}

/**

 * Returns a new captcha object

 * @param string Session ID

 * @param string Optional - engine to load

 * @param array Optional row to send to the captcha engine

 */

function captcha_object($session_id, $engine = false, $row = false)

{

	static $singletons = array();

	if ( !$engine )

	{

		$engine = getConfig('captcha_engine');

		if ( !$engine )

		{

			$engine = 'freecap';

		}

	}

	if( !extension_loaded("gd") || !function_exists("gd_info") || !function_exists('imagettftext') || !function_exists('imagepng') || !function_exists('imagecreatefromjpeg') )

	{

		$engine = 'failsafe';

	}

	if ( !class_exists("captcha_engine_$engine") )

	{

		require_once ENANO_ROOT . "/includes/captcha/engine_{$engine}.php";

	}

	if ( !class_exists("captcha_engine_$engine") )

	{

		throw new Exception("Expected but couldn't find class for captcha engine: captcha_engine_$engine");

	}

	$class = "captcha_engine_$engine";

	return new $class($session_id, $row);

}

?>