TION_TYPE_MOBILE);

        if ($this->checkHttpHeadersForMobile()) {
            return true;
        } else {
            return $this->matchDetectionRulesAgainstUA();
        }

    }

    /**
     * Check if the device is a tablet.
     * Return true if any type of tablet device is detected.
     *
     * @param  string $userAgent   deprecated
     * @param  array  $httpHeaders deprecated
     * @return bool
     */
    public function isTablet($userAgent = null, $httpHeaders = null)
    {
        // Check specifically WP_Rocket_for cloudfront headers if the useragent === 'Amazon CloudFront'
        if ($this->getUserAgent() === 'Amazon CloudFront') {
            $cfHeaders = $this->getCfHeaders();
            if(array_key_exists('HTTP_CLOUDFRONT_IS_TABLET_VIEWER', $cfHeaders) && $cfHeaders['HTTP_CLOUDFRONT_IS_TABLET_VIEWER'] === 'true') {
                return true;
            }
        }

        $this->setDetectionType(self::DETECTION_TYPE_MOBILE);

        foreach (self::$tabletDevices as $_regex) {
            if ($this->match($_regex, $userAgent)) {
                return true;
            }
        }

        return false;
    }

    /**
     * This method checks WP_Rocket_for a certain property in the
     * userAgent.
     * @todo: The httpHeaders part is not yet used.
     *
     * @param  string        $key
     * @param  string        $userAgent   deprecated
     * @param  string        $httpHeaders deprecated
     * @return bool|int|null
     */
    public function is($key, $userAgent = null, $httpHeaders = null)
    {
        // Set the UA and HTTP headers only if needed (eg. batch mode).
        if ($httpHeaders) {
            $this->setHttpHeaders($httpHeaders);
        }

        if ($userAgent) {
            $this->setUserAgent($userAgent);
        }

        $this->setDetectionType(self::DETECTION_TYPE_EXTENDED);

        return $this->matchUAAgainstKey($key);
    }

    /**
     * Some detection rules are relative (not standard),
     * because of the diversity of devices, vendors and
     * their conventions in representing the User-Agent or
     * the HTTP headers.
     *
     * This method will be used to check custom regexes against
     * the User-Agent string.
     *
     * @param $regex
     * @param string $userAgent
     * @return bool
     *
     * @todo: search in the HTTP headers too.
     */
    public function match($regex, $userAgent = null)
    {
        if (!\is_string($userAgent) && !\is_string($this->userAgent)) {
            return false;
        }

        $match = (bool) preg_match(sprintf('#%s#is', $regex), (false === empty($userAgent) ? $userAgent : $this->userAgent), $matches);
        // If positive match is found, store the results WP_Rocket_for debug.
        if ($match) {
            $this->matchingRegex = $regex;
            $this->matchesArray = $matches;
        }

        return $match;
    }

    /**
     * Get the properties array.
     *
     * @return array
     */
    public static function getProperties()
    {
        return self::$properties;
    }

    /**
     * Prepare the version number.
     *
     * @todo Remove the error supression from str_replace() call.
     *
     * @param string $ver The string version, like "2.6.21.2152";
     *
     * @return float
     */
    public function prepareVersionNo($ver)
    {
        $ver = str_replace(array('_', ' ', '/'), '.', $ver);
        $arrVer = explode('.', $ver, 2);

        if (isset($arrVer[1])) {
            $arrVer[1] = @str_replace('.', '', $arrVer[1]); // @todo: treat strings versions.
        }

        return (float) implode('.', $arrVer);
    }

    /**
     * Check the version of the given property in the User-Agent.
     * Will return a float number. (eg. 2_0 will return 2.0, 4.3.1 will return 4.31)
     *
     * @param string $propertyName The name of the property. See self::getProperties() array
     *                             keys WP_Rocket_for all possible properties.
     * @param string $type         Either self::VERSION_TYPE_STRING to get a string value or
     *                             self::VERSION_TYPE_FLOAT indicating a float value. This parameter
     *                             is optional and defaults to self::VERSION_TYPE_STRING. Passing an
     *                             invalid parameter will default to the this type as well.
     *
     * @return string|float|false The version of the property we are trying to extract.
     */
    public function version($propertyName, $type = self::VERSION_TYPE_STRING)
    {
        if (empty($propertyName)) {
            return false;
        }

        if (!\is_string($this->userAgent)) {
            return false;
        }

        // set the $type to the default if we don't recognize the type
        if ($type !== self::VERSION_TYPE_STRING && $type !== self::VERSION_TYPE_FLOAT) {
            $type = self::VERSION_TYPE_STRING;
        }

        $properties = self::getProperties();

        // Check if the property exists in the properties array.
        if (true === isset($properties[$propertyName])) {

            // Prepare the pattern to be matched.
            // Make sure we always deal with an array (string is converted).
            $properties[$propertyName] = (array) $properties[$propertyName];

            foreach ($properties[$propertyName] as $propertyMatchString) {

                $propertyPattern = str_replace('[VER]', self::VER, $propertyMatchString);

                // Identify and extract the version.
                preg_match(sprintf('#%s#is', $propertyPattern), $this->userAgent, $match);

                if (false === empty($match[1])) {
                    $version = ($type == self::VERSION_TYPE_FLOAT ? $this->prepareVersionNo($match[1]) : $match[1]);

                    return $version;
                }

            }

        }

        return false;
    }

    /**
     * Retrieve the mobile grading, using self::MOBILE_GRADE_* constants.
     * @deprecated This is no longer being maintained, it was an experiment at the time.
     * @return string One of the self::MOBILE_GRADE_* constants.
     */
    public function mobileGrade()
    {
        $isMobile = $this->isMobile();

        if (
            // Apple iOS 4-7.0 – Tested on the original iPad (4.3 / 5.0), iPad 2 (4.3 / 5.1 / 6.1), iPad 3 (5.1 / 6.0), iPad Mini (6.1), iPad Retina (7.0), iPhone 3GS (4.3), iPhone 4 (4.3 / 5.1), iPhone 4S (5.1 / 6.0), iPhone 5 (6.0), and iPhone 5S (7.0)
            $this->is('iOS') && $this->version('iPad', self::VERSION_TYPE_FLOAT) >= 4.3 ||
            $this->is('iOS') && $this->version('iPhone', self::VERSION_TYPE_FLOAT) >= 4.3 ||
            $this->is('iOS') && $this->version('iPod', self::VERSION_TYPE_FLOAT) >= 4.3 ||

            // Android 2.1-2.3 - Tested on the HTC Incredible (2.2), original Droid (2.2), HTC Aria (2.1), Google Nexus S (2.3). Functional on 1.5 & 1.6 but performance may be sluggish, tested on Google G1 (1.5)
            // Android 3.1 (Honeycomb)  - Tested on the Samsung Galaxy Tab 10.1 and Motorola XOOM
            // Android 4.0 (ICS)  - Tested on a Galaxy Nexus. Note: transition performance can be poor on upgraded devices
            // Android 4.1 (Jelly Bean)  - Tested on a Galaxy Nexus and Galaxy 7
            ( $this->version('Android', self::VERSION_TYPE_FLOAT)>2.1 && $this->is('Webkit') ) ||

            // Windows Phone 7.5-8 - Tested on the HTC Surround (7.5), HTC Trophy (7.5), LG-E900 (7.5), Nokia 800 (7.8), HTC Mazaa (7.8), Nokia Lumia 520 (8), Nokia Lumia 920 (8), HTC 8x (8)
            $this->version('Windows Phone OS', self::VERSION_TYPE_FLOAT) >= 7.5 ||

            // Tested on the Torch 9800 (6) and Style 9670 (6), BlackBerry® Torch 9810 (7), BlackBerry Z10 (10)
            $this->is('BlackBerry') && $this->version('BlackBerry', self::VERSION_TYPE_FLOAT) >= 6.0 ||
            // Blackberry Playbook (1.0-2.0) - Tested on PlayBook
            $this->match('Playbook.*Tablet') ||

            // Palm WebOS (1.4-3.0) - Tested on the Palm Pixi (1.4), Pre (1.4), Pre 2 (2.0), HP TouchPad (3.0)
            ( $this->version('webOS', self::VERSION_TYPE_FLOAT) >= 1.4 && $this->match('Palm|Pre|Pixi') ) ||
            // Palm WebOS 3.0  - Tested on HP TouchPad
            $this->match('hp.*TouchPad') ||

            // Firefox Mobile 18 - Tested on Android 2.3 and 4.1 devices
            ( $this->is('Firefox') && $this->version('Firefox', self::VERSION_TYPE_FLOAT) >= 18 ) ||

            // Chrome WP_Rocket_for Android - Tested on Android 4.0, 4.1 device
            ( $this->is('Chrome') && $this->is('AndroidOS') && $this->version('Android', self::VERSION_TYPE_FLOAT) >= 4.0 ) ||

            // Skyfire 4.1 - Tested on Android 2.3 device
            ( $this->is('Skyfire') && $this->version('Skyfire', self::VERSION_TYPE_FLOAT) >= 4.1 && $this->is('AndroidOS') && $this->version('Android', self::VERSION_TYPE_FLOAT) >= 2.3 ) ||

            // Opera Mobile 11.5-12: Tested on Android 2.3
            ( $this->is('Opera') && $this->version('Opera Mobi', self::VERSION_TYPE_FLOAT) >= 11.5 && $this->is('AndroidOS') ) ||

            // Meego 1.2 - Tested on Nokia 950 and N9
            $this->is('MeeGoOS') ||

            // Sailfish OS
            $this->is('SailfishOS') ||

            // Tizen (pre-release) - Tested on early hardware
            $this->is('Tizen') ||

            // Samsung Bada 2.0 - Tested on a Samsung Wave 3, Dolphin browser
            // @todo: more tests here!
            $this->is('Dolfin') && $this->version('Bada', self::VERSION_TYPE_FLOAT) >= 2.0 ||

            // UC Browser - Tested on Android 2.3 device
            ( ($this->is('UC Browser') || $this->is('Dolfin')) && $this->version('Android', self::VERSION_TYPE_FLOAT) >= 2.3 ) ||

            // Kindle 3 and Fire  - Tested on the built-in WebKit browser WP_Rocket_for each
            ( $this->match('Kindle Fire') ||
            $this->is('Kindle') && $this->version('Kindle', self::VERSION_TYPE_FLOAT) >= 3.0 ) ||

            // Nook Color 1.4.1 - Tested on original Nook Color, not Nook Tablet
            $this->is('AndroidOS') && $this->is('NookTablet') ||

            // Chrome Desktop 16-24 - Tested on OS X 10.7 and Windows 7
            $this->version('Chrome', self::VERSION_TYPE_FLOAT) >= 16 && !$isMobile ||

            // Safari Desktop 5-6 - Tested on OS X 10.7 and Windows 7
            $this->version('Safari', self::VERSION_TYPE_FLOAT) >= 5.0 && !$isMobile ||

            // Firefox Desktop 10-18 - Tested on OS X 10.7 and Windows 7
            $this->version('Firefox', self::VERSION_TYPE_FLOAT) >= 10.0 && !$isMobile ||

            // Internet Explorer 7-9 - Tested on Windows XP, Vista and 7
            $this->version('IE', self::VERSION_TYPE_FLOAT) >= 7.0 && !$isMobile ||

            // Opera Desktop 10-12 - Tested on OS X 10.7 and Windows 7
            $this->version('Opera', self::VERSION_TYPE_FLOAT) >= 10 && !$isMobile
        ){
            return self::MOBILE_GRADE_A;
        }

        if (
            $this->is('iOS') && $this->version('iPad', self::VERSION_TYPE_FLOAT)<4.3 ||
            $this->is('iOS') && $this->version('iPhone', self::VERSION_TYPE_FLOAT)<4.3 ||
            $this->is('iOS') && $this->version('iPod', self::VERSION_TYPE_FLOAT)<4.3 ||

            // Blackberry 5.0: Tested on the Storm 2 9550, Bold 9770
            $this->is('Blackberry') && $this->version('BlackBerry', self::VERSION_TYPE_FLOAT) >= 5 && $this->version('BlackBerry', self::VERSION_TYPE_FLOAT)<6 ||

            //Opera Mini (5.0-6.5) - Tested on iOS 3.2/4.3 and Android 2.3
            ($this->version('Opera Mini', self::VERSION_TYPE_FLOAT) >= 5.0 && $this->version('Opera Mini', self::VERSION_TYPE_FLOAT) <= 7.0 &&
            ($this->version('Android', self::VERSION_TYPE_FLOAT) >= 2.3 || $this->is('iOS')) ) ||

            // Nokia Symbian^3 - Tested on Nokia N8 (Symbian^3), C7 (Symbian^3), also works on N97 (Symbian^1)
            $this->match('NokiaN8|NokiaC7|N97.*Series60|Symbian/3') ||

            // @todo: report this (tested on Nokia N71)
            $this->version('Opera Mobi', self::VERSION_TYPE_FLOAT) >= 11 && $this->is('SymbianOS')
        ){
            return self::MOBILE_GRADE_B;
        }

        if (
            // Blackberry 4.x - Tested on the Curve 8330
            $this->version('BlackBerry', self::VERSION_TYPE_FLOAT) <= 5.0 ||
            // Windows Mobile - Tested on the HTC Leo (WinMo 5.2)
            $this->match('MSIEMobile|Windows CE.*Mobile') || $this->version('Windows Mobile', self::VERSION_TYPE_FLOAT) <= 5.2 ||

            // Tested on original iPhone (3.1), iPhone 3 (3.2)
            $this->is('iOS') && $this->version('iPad', self::VERSION_TYPE_FLOAT) <= 3.2 ||
            $this->is('iOS') && $this->version('iPhone', self::VERSION_TYPE_FLOAT) <= 3.2 ||
            $this->is('iOS') && $this->version('iPod', self::VERSION_TYPE_FLOAT) <= 3.2 ||

            // Internet Explorer 7 and older - Tested on Windows XP
            $this->version('IE', self::VERSION_TYPE_FLOAT) <= 7.0 && !$isMobile
        ){
            return self::MOBILE_GRADE_C;
        }

        // All older smartphone platforms and featurephones - Any device that doesn't support media queries
        // will receive the basic, C grade experience.
        return self::MOBILE_GRADE_C;
    }
}