<?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);

}

?>