<?php
/**
 * Zend Framework (http://framework.zend.com/)
 *
 * @link      http://github.com/zendframework/zf2 for the canonical source repository
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license   http://framework.zend.com/license/new-bsd New BSD License
 * @package   Zend_Session
 */

namespace Zend\Session\Validator;

/**
 * @category   Zend
 * @package    Zend_Session
 * @subpackage Validator
 */
class HttpUserAgent implements ValidatorInterface
{
    /**
     * Internal data
     *
     * @var string
     */
    protected $data;

    /**
     * Constructor
     * get the current user agent and store it in the session as 'valid data'
     *
     * @param string|null $data
     */
    public function __construct($data = null)
    {
        if (empty($data)) {
            $data = isset($_SERVER['HTTP_USER_AGENT'])
                  ? $_SERVER['HTTP_USER_AGENT']
                  : null;
        }
        $this->data = $data;
    }

    /**
     * isValid() - this method will determine if the current user agent matches the
     * user agent we stored when we initialized this variable.
     *
     * @return bool
     */
    public function isValid()
    {
        $userAgent = isset($_SERVER['HTTP_USER_AGENT'])
                   ? $_SERVER['HTTP_USER_AGENT']
                   : null;

        return ($userAgent === $this->getData());
    }

    /**
     * Retrieve token for validating call
     *
     * @return string
     */
    public function getData()
    {
        return $this->data;
    }

    /**
     * Return validator name
     *
     * @return string
     */
    public function getName()
    {
        return __CLASS__;
    }
}