<?php
abstract class Qs_Sys_Request
{
    protected static $_baseUrl;
    protected static $_baseFinalUrl;
    protected static $_url;
    protected static $_finalUrl;
    protected static $_instance = null;

    public static function getInstance()
    {
        if (null === Qs_Request::$_instance) {
            Qs_Request::$_instance = new Qs_Request();
        }
        return Qs_Request::$_instance;
    }

    protected static function _getBaseUrl($final = false)
    {
        $propertyName = ($final) ? '_baseFinalUrl' : '_baseUrl';
        if (null === Qs_Request::${$propertyName}) {
            Qs_Request::${$propertyName} = Qs_Constant::get('BASE_URL_LANGUAGE');
            $page = Qs_Constant::get(($final) ? 'CURRENT_PAGE_FINAL' : 'CURRENT_PAGE');
            if (!empty($page)) {
                Qs_Request::${$propertyName} .= '/' . $page;
            }
        }
        return Qs_Request::${$propertyName};
    }

    protected static function _setUrl($url, $final = false)
    {
        $propertyName = ($final) ? '_url' : '_finalUrl';
        Qs_Request::${$propertyName} = $url;
    }

    protected static function _getUrl($final = false)
    {
        $propertyName = ($final) ? '_url' : '_finalUrl';
        if (null === Qs_Request::${$propertyName}) {
            $url = Qs_Request::_getBaseUrl($final);
            if (!empty($_SERVER['QUERY_STRING'])) {
                $url .= '?' . $_SERVER['QUERY_STRING'];
            }
            Qs_Request::_setUrl($url, $final);
        }
        return Qs_Request::${$propertyName};
    }

    protected static function _getUrlExclude($args = array(), $final = false)
    {
        $url = Qs_Request::_getBaseUrl($final);
        $queryParams = array_diff_key($_GET, array_combine($args, $args));
        $queryString = http_build_query($queryParams);
        if (!empty($queryString)) {
            $url .= '?' . $queryString;
        }
        return $url;
    }

    public static function getFinalBaseUrl()
    {
        return Qs_Request::_getBaseUrl(true);
    }

    public static function getBaseUrl()
    {
        return Qs_Request::_getBaseUrl(false);
    }

    public static function getFinalUrl()
    {
        return Qs_Request::_getUrl(true);
    }

    public static function getUrl()
    {
        return Qs_Request::_getUrl(false);
    }

    public static function setUrl($url)
    {
        Qs_Request::_setUrl($url ,false);
    }

    public static function setFinalUrl($url)
    {
        Qs_Request::_setUrl($url, false);
    }

    public static function getUrlExclude()
    {
         $args = func_get_args();
         return Qs_Request::_getUrlExclude($args, false);
    }

    public static function getFinalUrlExclude()
    {
         $args = func_get_args();
         return Qs_Request::_getUrlExclude($args, true);
    }

    public static function getLanguageUrl($language)
    {
        $url = Qs_Constant::get('BASE_URL');
        if ($language !== Qs_Constant::get('DEFAULT_LANGUAGE')) {
            $url .= '/' . $language;
        }
        $url .= '/' . Qs_Constant::get('CURRENT_PAGE');
        if (!empty($_SERVER['QUERY_STRING'])) {
            $url .= '?' . $_SERVER['QUERY_STRING'];
        }
        return $url;
    }

    protected static function _getValue($array, $name, $checkQuotes = false, $default = null)
    {
        if (null === ($value = Qs_Array::get($array, $name))) {
            return $default;
        }
        if ($checkQuotes && version_compare(phpversion(), '5.3.0', '<') && 1 == get_magic_quotes_gpc()) {
            $value = Qs_Request::_recursiveFilter('stripslashes', $value);
        }
        return $value;
    }

    protected static function _recursiveFilter($filter, $value)
    {
        if (is_array($value)) {
            $cleanValues = array();
            foreach ($value as $k => $v) {
                $cleanValues[$k] = Qs_Request::_recursiveFilter($filter, $v);
            }
            return $cleanValues;
        } else {
            return call_user_func($filter, $value);
        }
    }

    public static function getPostValue($name, $default = null)
    {
        return Qs_Request::_getValue($_POST, $name, true, $default);
    }

    public static function getGetValue($name, $default = null)
    {
        return Qs_Request::_getValue($_GET, $name, true, $default);
    }

    public static function getRequestValue($name, $default = null)
    {
        return Qs_Request::_getValue($_REQUEST, $name, true, $default);
    }

    public static function getCookieValue($name, $default = null)
    {
        return Qs_Request::_getValue($_COOKIE, $name, false, $default);
    }

    public static function getHeader($header)
    {
        if (empty($header)) {
            return false;
        }
        // Try to get it from the $_SERVER array first
        $temp = 'HTTP_' . strtoupper(str_replace('-', '_', $header));
        if (!empty($_SERVER[$temp])) {
            return $_SERVER[$temp];
        }
        // This seems to be the only way to get the Authorization header on
        // Apache
        if (function_exists('apache_request_headers')) {
            $headers = apache_request_headers();
            if (!empty($headers[$header])) {
                return $headers[$header];
            }
        }
        return false;
    }

    public static function isXmlHttpRequest()
    {
        return (Qs_Request::getHeader('X_REQUESTED_WITH') == 'XMLHttpRequest');
    }

    public static function getPost()
    {
        return Qs_Request::_get($_POST);
    }

    public static function getGet()
    {
        return Qs_Request::_get($_GET);
    }

    protected static function _get($array)
    {
        if (1 == get_magic_quotes_gpc()) {
            $array = Qs_Request::_recursiveFilter('stripslashes', $array);
        }
        return $array;
    }

    /**
     * Checks whether the url belongs to the site
     * The protocol is ignored
     * @param string $url
     * @return bool
     */
    public static function isOwnUrl($url)
    {
        if (empty($url) || !is_string($url)) {
            return false;
        }
        $url = substr($url, strpos($url, '://') + 3);
        $baseUrl = substr(BASE_URL, strpos(BASE_URL, '://') + 3);
        return (0 === strpos($url, $baseUrl));
    }

    /**
     * Checks whether the referer belongs to the site
     * @static
     * @return bool
     */
    public static function isOwnReferer()
    {
        $referer = Qs_Array::get($_SERVER, 'HTTP_REFERER');
        return (null === $referer) ? false : Qs_Request::isOwnUrl($referer);
    }
}