public static function isMobile($check = true)
    {
        if ($check) {
            if (self::get('nomobile') !== null) {
                if (self::get('nomobile')) {
                    waSystem::getInstance()->getStorage()->write('nomobile', true);
                } else {
                    waSystem::getInstance()->getStorage()->remove('nomobile');
                }
            } elseif (self::get('mobile')) {
                waSystem::getInstance()->getStorage()->remove('nomobile');
            }
            if (waSystem::getInstance()->getStorage()->read('nomobile')) {
                return false;
            }
        }

        if (self::$mobile !== null) {
            return self::$mobile;
        }
        $user_agent = self::server('HTTP_USER_AGENT');

        $desktop_platforms = array(
            'ipad'       => 'ipad',
            'galaxy-tab' => 'android.*?GT\-P',
        );
        foreach ($desktop_platforms as $pattern) {
            if (preg_match('/'.$pattern.'/i', $user_agent)) {
                self::$mobile = false;
                return false;
            }
        }

        $mobile_platforms = array(
            "google-mobile" => "googlebot\-mobile",
            "android"    => "android",
            "blackberry" => "(blackberry|rim tablet os)",
            "iphone"     => "(iphone|ipod)",
            "opera"      => "opera (mini|mobi|mobile)",
            "palm"       => "(palmos|avantgo|blazer|elaine|hiptop|palm|plucker|xiino)",
            "windows"    => "windows\sce;\s(iemobile|ppc|smartphone)",
            "generic"    => "(kindle|mobile|mmp|midp|o2|pda|pocket|psp|symbian|smartphone|treo|up.browser|up.link|vodafone|wap)"
        );
        foreach ($mobile_platforms as $id => $pattern) {
            if (preg_match('/'.$pattern.'/i', $user_agent)) {
                self::$mobile = $id;
                return $id;
            }
        }

        self::$mobile = false;
        return false;
    }