class StreamProviderTwitch
{
    const clipUidPattern = 'www\.twitch\.tv\/([^\"][a-zA-Z0-9-_]+)[&\"]\/embed\/';
    const thumbJsonPattern = 'https://api.twitch.tv/kraken/streams/()';

    private static function getUid( $code )
    {
        $pattern = self::clipUidPattern;

        return preg_match("~{$pattern}~", $code, $match) ? $match[1] : null;
    }

    public static function getThumbUrl( $code )
    {
        if ( ($uid = self::getUid($code)) !== null )
        {
            $jsonUrl = str_replace('()', $uid, self::thumbJsonPattern);

            $fileCont = @file_get_contents($jsonUrl);

            if ( strlen($fileCont) )
            {
                
                $metaObj = @json_decode($fileCont);

                if ( $metaObj )
                {
                    $url = @$metaObj->streams[0]->preview->medium;
                }
            }

            return !empty($url) ? $url : StreamProviders::PROVIDER_UNDEFINED;
        }

        return StreamProviders::PROVIDER_UNDEFINED;
    }
}