function get_html_body(){
        $hostname = '{imap.gmail.com:993/imap/ssl}INBOX';
        $username = $this->config->item('competitor_email_sync')['email'];
        $password = $this->config->item('competitor_email_sync')['password'];

        $inbox = imap_open($hostname,$username,$password);
        if(!$inbox) {
            echo 'connot connec to email server'.PHP_EOL.imap_last_error();
            die;
        }

        $emails = imap_search($inbox,'UNFLAGGED BODY "'.$keyword.'"');

        if($emails) {
            foreach ($emails as $email_number) {
                list($email_from, $subject) = $this->handle_overview($inbox, $email_number);

                if(!isset($configs[$email_from])){
                    echo 'not configged email sender: '.$email_from.PHP_EOL;
                    continue;
                }
                if (strpos($subject, 'Fwd') === false) {
                    echo 'wrong subject:'. $subject. PHP_EOL;
                    //TODO determine the filter critiria
                    continue;
                }

                $html_body = $this->get_html($inbox, $email_number);
                $b64_test = base64_decode($html_body);
                if($b64_test){
                    $html_body = $b64_test;
                }
            }
        }else{
            echo PHP_EOL.' no email found.'.PHP_EOL;
        }

        /* close the connection */
        imap_close($inbox);

}

function get_html($inbox, $email_number){
        $message = imap_fetchbody($inbox,$email_number,'2');
        $html_body = quoted_printable_decode($message);
        $html_body = mb_convert_encoding($html_body, 'utf-8', mb_detect_encoding($html_body));
        $html_body = mb_convert_encoding($html_body, 'html-entities', 'utf-8');

        if(!$html_body){
            $message = imap_fetchbody($inbox,$email_number,2);
            $html_body = quoted_printable_decode($message);
            $html_body = mb_convert_encoding($html_body, 'utf-8', mb_detect_encoding($html_body));
            $html_body = mb_convert_encoding($html_body, 'html-entities', 'utf-8');
        }

        return $html_body;
    }
function handle_overview($inbox, $email_number){
        $overview = imap_fetch_overview($inbox, $email_number);
        $email_from = $overview[0]->from;
        $email_from = explode('<', $email_from)[1];
        $email_from = strtolower(trim(str_replace('>', '', $email_from)));

        $subject = imap_utf8($overview[0]->subject);
        return [$email_from, $subject];
    }