TEST DE TURING ACCESSIBLE - CLASSE PHP5

<?php
/*******************************************************************************
* Software: Turing Test class                                                               *
* Version:  0.2                                                               *
* Date:     2007-01-20                                                         *
* Author:   William POTTIER                                                   *
* License:  Freeware                                                           *
*                                                                              *
* You may use, modify and redistribute this software as you wish.              *
*******************************************************************************/

class Turing
{
	// List of many word wich may be use.
	private $dictionnary = array(
 			'programmation',
			'interface',
			'variable',
			'apprentissage'
 			);
 	// List of questions types
	private $questions = array(
 			'Indiquer le résultat de la somme de %x et %y',
 			'Indiquer le plus grand nombre entre %x et %y',
 			'Indiquer la lettre n°%u du mot "%mot_z"',
 			'Indiquer le plus petit nombre entre %x et %y'
 			);
 	// Results that corresponds with associated questions.
	private $results = array(
	'addition(x,y)',
	'_max(x,y)',
	'letterOfWord(u,mot_z)',
	'_min(x,y)' 
	);
	private $nb, $u, $x, $y, $z,$mot_z;
	
	////////////////////////////////////////
	// Constructor : just many simple test
	public function __construct()
	{
	  	// We check if Session is open
		if(session_id() == '')
			throw new Exception('Can\'t use Turing test because session is close.');
	}
	
	//////////////////////////////////////////
	// a function for callback (for $results)
	private function addition($a, $b)
	{
		return $a+$b;
	}
	
	//////////////////////////////////////////
	// a function for callback (for $results)
	private function letterOfWord($pos, $mot)
	{
		return $mot[$pos];
	}
	
	private function _max($a, $b)
	{
		return max(array($a, $b));
	}
	
	private function _min($a, $b)
	{
		return min(array($a, $b));
	}
	
	//////////////////////////////////////////////////////
	// We pick a question from our list and we return it
	public function GenerateQuestion($force_new = 0)
	{
	  	if($this->nb == '' || $force_new == 1)
	  		$this->nb = mt_rand(0, count($this->questions)-1);
		
		// We get the random number
		$this->x = mt_rand(1, 50);
		$this->y = mt_rand(1, 50);
		$this->z = mt_rand(0, count($this->dictionnary)-1);
		$this->mot_z = $this->dictionnary[$this->z];
		$this->u = mt_rand(0,strlen($this->mot_z)-1); 
		
		// We get the result and we save it in $_SESSION
		$_SESSION['turing'] = $this->GetResult();
		
		$search = array('%x', '%y', '%mot_z', '%u');
		$replace = array($this->x, $this->y, $this->mot_z, $this->u+1);
		$question = str_replace($search, $replace, $this->questions[$this->nb]);
		  
		return $question;
	}
	
	////////////////////////////////////////////////////////
	// we return the result associated with the number $nb
	private function GetResult()
	{
		$result = $this->results[$this->nb];
		// We explode the string to get function name and param list
		$temp1 = explode('(', $result);
		// Good, wa have the callback
		$callback = $temp1[0];
		// Now the params
		$params = trim($temp1[1], ')');
		$param = explode(',', $params);
		$count_param = count($param);
		for($i = 0; $i < $count_param; $i++)
		{
			$param_callback[$i] = $this->$param[$i];
		}
		
		// We run the callback
		return call_user_method_array($callback, $this, $param_callback);
	}
}
?>