<?php
/**
 * Require the correct answer for a randomly choosen question for successful registration.
 *
 * Based on ideas from http://www.punbb.fr/forums/viewtopic.php?pid=18554#p18554
 *
 * This UR (user registration) verification module requires the
 * user to enter the correct answer to a question (password) for a successful
 * registration.
 *
 * To implement, set the following in wikka.config.php:
 *    'UR_validation_modules' => 'URTextCaptchaModule'
 *    'UR_captcha_questions' => array(
 *        'First question' => 'Answer',
 *        'Second question' => 'Answer',
 *        ),
 * (If combined with other modules, separate each module with a
 * comma.)
 *
 * @version 0.2
 * @see libs/userregistration.class.php
 * @see URAuth, URAuthTmpl
 *
 * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License
 * @filesource
 *
 * @author {@link http://wikkawiki.org/BrianKoontz Brian Koontz}  (Invite Code module)
 * @author {@link http://wikkawiki.org/NilsLindenberg NilsLindenberg} (extended)
 *
 * @see libs/userregistration.class.php
 * @see URAuth, URAuthTmpl
 *
 * @todo    i18n
 * @todo    Add number to the md5 to get some more randomness?
 */

include_once('libs/userregistration.class.php');

class URTextCaptchaModule extends URAuthTmpl
{   
    /**
    * Array for questions (key) and answers (value) for the captcha.
    */
    var $captcha_questions;
   
    /**
    * Constructor. Load questions and answers from the config file.
    */
    function URTextCaptchaModule(&$wakka)
    {
        $this->URAuthTmpl($wakka);   
        if(isset($wakka->config['UR_captcha_questions']))
        {
                $this->captcha_questions = $wakka->config['UR_captcha_questions'];
        }
    }
   
    /**
    * Display input form with question, answer and encoded question (hidden field).
    */
    function URAuthTmplDisplay()
    {
        if(!isset($this->captcha_questions) || !is_array($this->captcha_questions))
        {
            echo '<em class="error">Error in URTextCaptcha module</em>';
        }
        else {
            $questions=array_keys($this->captcha_questions);
            if (FALSE === $questions)
            {
                echo '<em class="error">Error in URTextCaptcha module</em>';
                return;
            }
            //choose random-question
            $nr = rand(0,count($this->captcha_questions)-1);
           
            echo '<label for="UR_captcha">'.$questions[$nr].'</label>'."\n";
            echo '<input type="text" name="UR_captcha" id="UR_captcha" size="10" />'."\n";
            echo '<input name="UR_cap_q" value="'.md5($questions[$nr]).'" type="hidden" />';
        }       
    }

    /**
    * Verify if the encoded question exists and if the answer is correct.
    */
    function URAuthTmplVerify()
    {
        if(!isset($this->captcha_questions))
        {
            return FALSE;
        }
        if(isset($_POST['UR_captcha']) && isset($_POST['UR_cap_q']))
        {
            foreach ($this->captcha_questions as $k => $v)
            {
                if (md5($k) == $_POST['UR_cap_q'])
                {
                    if ($v == $_POST['UR_captcha']) return TRUE;
                }
            }
        }
        return FALSE;
    }
}
?>

'UR_validation_modules' => 'URTextCaptchaModule',

'UR_captcha_questions' => array(
 'First question' => 'Answer',
 'Second question' => 'Answer',
 ),

'UR_captcha_questions' => array(
 'Please enter the registration code provided by your admin' => 'registercode',
 ),