<?php
    
    /*
     * @author Borja Martín <borjam@dagi3d.net>
     */
     
	class ConversationalContext {
		
        var $_cid;
        var $_cidvalue;
        
		function ConversationalContext($cid) {
            
            $this->_cid = $cid;
            
            $exists = isset($_REQUEST[$this->_cid]) 
                    && $_REQUEST[$this->_cid] != ''
                    && isset($_SESSION[$this->_cid])
                    && isset($_SESSION[$this->_cid][$_REQUEST[$this->_cid]]);
                    
            $this->_cidvalue = ($exists)
                    ? $_REQUEST[$this->_cid] 
                    : $this->_startConversation();
        }
        
        function getVariable($name) {
                                                
            if (array_key_exists($this->_cid, $_SESSION)
                    && array_key_exists($this->_cidvalue, $_SESSION[$this->_cid])
                    && array_key_exists($name, $_SESSION[$this->_cid][$this->_cidvalue])) {
                    
                return $_SESSION[$this->_cid][$this->_cidvalue][$name];                    
            } else {
                return null;
            }
        }
        
        function setVariable($name, $value) {
            
            if (!array_key_exists($this->_cidvalue, $_SESSION[$this->_cid])) return;
            
            $_SESSION[$this->_cid][$this->_cidvalue][$name] = $value;

        }
        
        function _startConversation() {
            
            if (!array_key_exists($this->_cid, $_SESSION)) {
                $_SESSION[$this->_cid] = array();
            }
            
            $cidvalue = count($_SESSION[$this->_cid]);
            $_SESSION[$this->_cid][$cidvalue] = array();
            
            return $cidvalue;
        }
        
        function getId() {
            return $this->_cidvalue;
        }
	}
?>