text:
<?php

namespace Mautic\EmailBundle\Helper;

use Mautic\CoreBundle\Factory\MauticFactory;
use Mautic\CoreBundle\Helper\DateTimeHelper;
use Mautic\EmailBundle\MonitoredEmail\Message;
use Mautic\LeadBundle\Entity\DoNotContact;

/**
 * Class MessageHelper
 */
class MessageHelper
{
    /**
     * @var MauticFactory
     */
    protected $factory;

    /**
     * @var \Doctrine\DBAL\Connection
     */
    protected $db;

    /**
     * @var \Monolog\Logger
     */
    protected $logger;

    /**
     * @param MauticFactory $factory
     */
    public function __construct(MauticFactory $factory)
    {
        $this->factory = $factory;
        $this->db      = $factory->getDatabase();
        $this->logger  = $this->factory->getLogger();

    }

    /**
     * @param Message    $message
     * @param bool|false $allowBounce
     * @param bool|false $allowUnsubscribe
     *
     * @return bool
     */
    public function analyzeMessage(Message $message, $allowBounce = false, $allowUnsubscribe = false)
    {
        $dtHelper = new DateTimeHelper();

        // Assume is an unsubscribe
        $isUnsubscribe = $allowUnsubscribe;
        $isBounce      = false;
        $toEmail       = reset($message->to);

        // Check for bounce emails via + notation if applicable
        foreach ($message->to as $to => $name) {
            if (strpos($to, '+bounce') !== false) {
                $isBounce      = true;
                $isUnsubscribe = false;
                $toEmail       = $to;
                break;
            } elseif (strpos($to, '+unsubscribe')) {
                $isBounce      = false;
                $isUnsubscribe = true;
                $toEmail       = $to;
                break;
            }
        }

        $this->logger->debug("Analyzing message to {$message->toString}");
        // If message from Amazon SNS collect bounces and complaints
        if ($message->fromAddress=='no-reply@sns.amazonaws.com') {
            $message = json_decode(strtok($message->textPlain, "\n"), true);
            if ($message['notificationType']=='Bounce') {
                $isBounce = true;
                $isUnsubscribe = false;
                $toEmail = $message['mail']['source'];
                $amazonEmail = $message['bounce']['bouncedRecipients'][0]['emailAddress'];
            }
            elseif ($message['notificationType']=='Complaint') {
                $isBounce      = false;
                $isUnsubscribe = true;
                $toEmail       = $message['mail']['source'];
                $amazonEmail = $message['complaint']['complainedRecipients'][0]['emailAddress'];
            }
        }
        // Parse the to email if applicable
        if (preg_match('#^(.*?)\+(.*?)@(.*?)$#', $toEmail, $parts)) {
            if (strstr($parts[2], '_')) {
                // Has an ID hash so use it to find the lead
                list($ignore, $hashId) = explode('_', $parts[2]);
            }
        }

        $messageDetails = array();

        if ($allowBounce) {
            // If message from Amazon SNS fill details and don't process further
            if (isset($amazonEmail)){
            $messageDetails['email']=$amazonEmail;
            $messageDetails['rule_cat'] = 'unknown';
            $messageDetails['rule_no'] = '0013';
            $messageDetails['bounce_type'] = 'hard';
            $messageDetails['remove'] = 1;
            } else {
                if (!empty($message->dsnReport)) {
                    // Parse the bounce
                    $dsnMessage = ($message->dsnMessage) ? $message->dsnMessage : $message->textPlain;
                    $dsnReport  = $message->dsnReport;

                    $this->logger->addDebug('Delivery report found in message.');

                    // Try parsing the report
                    $messageDetails = $this->parseDsn($dsnMessage, $dsnReport);
                }

                if (empty($messageDetails['email']) || $messageDetails['rule_cat'] == 'unrecognized') {
                    // Check for the X-Failed-Recipients header
                    $bouncedEmail = (isset($message->xHeaders['x-failed-recipients'])) ? $message->xHeaders['x-failed-recipients'] : null;

                    if ($bouncedEmail) {
                        // Definitely a bounced email but need to find the reason
                        $this->logger->debug('Email found through x-failed-recipients header but need to search for a reason.');
                    } else {
                        $this->logger->debug('Bounce email or reason not found so attempting to parse the body.');
                    }

                    // Let's try parsing through the body parser
                    $messageDetails = $this->parseBody($message->textPlain, $bouncedEmail);
                }

                if (!$isBounce && !empty($messageDetails['email'])) {
                    // Bounce was found in message content
                    $isBounce      = true;
                    $isUnsubscribe = false;
                }
            }
        }

        if (!$isBounce && !$isUnsubscribe) {
            $this->logger->debug('No reason found to process.');
            return false;
        }

        // Search for the lead
        $stat = $leadId = $leadEmail = $emailId = null;
        if (!empty($hashId)) {
            $q = $this->db->createQueryBuilder();

            // Search by hashId
            $q->select('*')
                ->from(MAUTIC_TABLE_PREFIX.'email_stats', 's')
                ->where(
                    $q->expr()->eq('s.tracking_hash', ':hash')
                )
                ->setParameter('hash', $hashId);

            $results = $q->execute()->fetchAll();

            if (count($results)) {
                $stat      = $results[0];
                $leadId    = $stat['lead_id'];
                $leadEmail = $stat['email_address'];
                $emailId   = $stat['email_id'];

                $this->logger->debug('Stat found with ID# '.$stat['id']);
            }
            unset($results);
        }

        if (!$leadId) {
            if ($isBounce) {
                if (!empty($messageDetails['email'])) {
                    $leadEmail = $messageDetails['email'];
                } else {
                    // Email not found for the bounce so abort
                    $this->logger->error('BOUNCE ERROR: A lead could be found from the bounce email. From: ' . $message->fromAddress . '; To: ' . $message->toString . '; Subject: ' . $message->subject);

                    return false;
                }
            } else {
                $leadEmail = $message->fromAddress;
                $this->logger->debug('From address used: ' . $leadEmail);
            }

            // Search by first part and domain of email to find cases like me+mautic@domain.com
            list($email, $domain) = explode('@', strtolower($leadEmail));
            $email                = $email . '%';
            $domain               = '%@' . $domain;

            $q = $this->db->createQueryBuilder();
            $q->select('l.id, l.email')
                ->from(MAUTIC_TABLE_PREFIX.'leads', 'l')
                ->where(
                    $q->expr()->orX(
                        $q->expr()->eq('LOWER(l.email)', ':leademail'),
                        $q->expr()->andX(
                            $q->expr()->like('LOWER(l.email)', ':email'),
                            $q->expr()->like('LOWER(l.email)', ':domain')
                        )
                    )
                )
                ->setParameter('leademail', strtolower($leadEmail))
                ->setParameter('email', strtolower($email))
                ->setParameter('domain', strtolower($domain));
            $foundLeads = $q->execute()->fetchAll();
;
            foreach ($foundLeads as $lead) {
                if (strtolower($lead['email']) == strtolower($leadEmail)) {
                    // Exact match
                    $leadId = $lead['id'];

                    break;
                } elseif (strpos($lead['email'], '+') === false) {
                    // Not a plus style email so not a match

                    break;
                }

                if (preg_match('#^(.*?)\+(.*?)@(.*?)$#', $lead['email'], $parts)) {
                    $email = $parts[1] . '@' . $parts[3];

                    if (strtolower($email) == strtolower($leadEmail)) {
                        $this->logger->debug('Lead found through + alias: '. $lead['email']);

                        $leadId    = $lead['id'];
                        $leadEmail = $lead['email'];
                    }
                }
            }

            $this->logger->debug('Lead ID: ' . ($leadId ? $leadId : 'not found'));
        }

        if (!$leadId) {
            // A lead still could not be found
            return false;
        }

        // Set message details for unsubscribe requests
        if ($isUnsubscribe) {
            $messageDetails = array(
                'remove'   => true,
                'email'    => $leadEmail,
                'rule_cat' => 'unsubscribed',
                'rule_no'  => '0000'
            );
        }

        if ($isBounce && $stat) {
            // Update the stat with some details
            $openDetails = unserialize($stat['open_details']);
            if (!is_array($openDetails)) {
                $openDetails = array();
            }

            $openDetails['bounces'][] = array(
                'datetime' => $dtHelper->toUtcString(),
                'reason'   => $messageDetails['rule_cat'],
                'code'     => $messageDetails['rule_no'],
                'type'     => ($messageDetails['bounce_type'] === false) ? 'unknown' : $messageDetails['bounce_type']
            );

            $this->db->update(
                MAUTIC_TABLE_PREFIX.'email_stats',
                array(
                    'open_details' => serialize($openDetails),
                    'retry_count'  => $stat['retry_count']++,
                    'is_failed'    => ($messageDetails['remove'] || $stat['retry_count'] == 5) ? 1 : 0
                ),
                array('id' => $stat['id'])
            );

            $this->logger->debug('Stat updated');
        }

        // Is this a hard bounce or AN unsubscribe?
        if ($messageDetails['remove'] || ($stat && $stat['retry_count'] >= 5)) {
            $this->logger->debug('Adding DNC entry for ' . $leadEmail);

            // Check for an existing DNC entry
            $q = $this->db->createQueryBuilder();
            $q->select('dnc.id')
                ->from(MAUTIC_TABLE_PREFIX . 'lead_donotcontact', 'dnc')
                ->where('dnc.channel = "email"')
                ->where(
                    $q->expr()->eq('dnc.lead_id', ':leadId')
                )
                ->setParameter('leadId', $leadId);

            try {
                $exists = $q->execute()->fetchColumn();
            } catch (\Exception $e) {
                $this->logger->error($e->getMessage());
            }

            if (!empty($exists)) {
                $this->logger->debug('A DNC entry already exists for ' . $leadEmail);
            } else {
                $this->logger->debug('Existing not found so creating a new one.');
                // Create a DNC entry
                try {
                    $this->db->insert(
                        MAUTIC_TABLE_PREFIX . 'lead_donotcontact',
                        array(
                            'lead_id'      => $leadId,
                            'channel'      => 'email',
                            'channel_id'   => $emailId,
                            'date_added'   => $dtHelper->toUtcString(),
                            'reason'       => ($isUnsubscribe) ? DoNotContact::UNSUBSCRIBED : DoNotContact::BOUNCED,
                            'comments'     => $this->factory->getTranslator()->trans('mautic.email.bounce.reason.'.$messageDetails['rule_cat'])
                        )
                    );

                } catch (\Exception $e) {
                    $this->logger->error($e->getMessage());
                }
            }
        }

        $this->logger->debug(print_r($messageDetails, true));
    }

    /**
     * next rule number (BODY): 0238

     * default category:        unrecognized:

     * default rule no.:        0000

     */

    static $rule_categories = array(
        'antispam'       => array('remove' => 0, 'bounce_type' => 'blocked'),
        'autoreply'      => array('remove' => 0, 'bounce_type' => 'autoreply'),
        'concurrent'     => array('remove' => 0, 'bounce_type' => 'soft'),
        'content_reject' => array('remove' => 0, 'bounce_type' => 'soft'),
        'command_reject' => array('remove' => 1, 'bounce_type' => 'hard'),
        'internal_error' => array('remove' => 0, 'bounce_type' => 'temporary'),
        'defer'          => array('remove' => 0, 'bounce_type' => 'soft'),
        'delayed'        => array('remove' => 0, 'bounce_type' => 'temporary'),
        'dns_loop'       => array('remove' => 1, 'bounce_type' => 'hard'),
        'dns_unknown'    => array('remove' => 1, 'bounce_type' => 'hard'),
        'full'           => array('remove' => 0, 'bounce_type' => 'soft'),
        'inactive'       => array('remove' => 1, 'bounce_type' => 'hard'),
        'latin_only'     => array('remove' => 0, 'bounce_type' => 'soft'),
        'other'          => array('remove' => 1, 'bounce_type' => 'generic'),
        'oversize'       => array('remove' => 0, 'bounce_type' => 'soft'),
        'outofoffice'    => array('remove' => 0, 'bounce_type' => 'soft'),
        'unknown'        => array('remove' => 1, 'bounce_type' => 'hard'),
        'unrecognized'   => array('remove' => 0, 'bounce_type' => false,),
        'user_reject'    => array('remove' => 1, 'bounce_type' => 'hard'),
        'warning'        => array('remove' => 0, 'bounce_type' => 'soft')
    );

    /*
     * var for new line ending
     */
    static $bmh_newline = "
\n";

    /**
     * Defined bounce parsing rules for non-standard DSN
     *
     * @param string      $body       body of the email
     * @param string|null $knownEmail Bounced email if known through a x-failed-recipient header or the like and need to parse the body for a reason
     * @param boolean     $debug_mode show debug info. or not
     *
     * @return array    $result an array include the following fields: 'email', 'bounce_type','remove','rule_no','rule_cat'
     *                      if we could NOT detect the type of bounce, return rule_no = '0000'
     */
    static public function parseBody($body, $knownEmail = '', $debug_mode = false)
    {
        // initialize the result array
        $result = array(
            'email'       => $knownEmail,
            'bounce_type' => false,
            'remove'      => 0,
            'rule_cat'    => 'unrecognized',
            'rule_no'     => '0000'
        );

        // ======== rule =========

        /**
         * Email is already known likely for a x-failed-recipients header; most likely Gmail bounce
         */
        if ('' !== $knownEmail) {
            /*
             * rule: mailbox unknown;
             * sample:
             * The error that the other server returned was:
             * 550-5.1.1 The email account that you tried to reach does not exist.
             */
            if (preg_match("/email.*?does not exist/i", $body, $match)) {
                $result['rule_cat'] = 'unknown';
                $result['rule_no'] = '0237';
            }

            /*
             * rule: mailbox unknown;
             * sample:
             * The error that the other server returned was:
             * 553-5.1.2 We weren't able to find the recipient domain.
             */
            elseif (preg_match("/find the recipient domain/i", $body, $match)) {
                $result['rule_cat'] = 'unknown';
                $result['rule_no'] = '0237';
            }

            /*
             * rule: mailbox inactive;
             * sample:
             * The error that the other server returned was:
             * 550-5.2.1 The email account that you tried to reach is disabled.
             */
            elseif (preg_match("/email.*?disabled/i", $body, $match)) {
                $result['rule_cat'] = 'inactive';
                $result['rule_no'] = '0171';
            }

            /*
             * rule: mailbox warning;
             * sample:
             * The error that the other server returned was:
             * 550-5.2.1 The user you are trying to contact is receiving mail at a rate that prevents additional messages from being delivered.
             */
            elseif (preg_match("/user.*?rate that prevents/i", $body, $match)) {
                $result['rule_cat'] = 'warning';
                $result['rule_no'] = '0000';
            }

            /*
            * rule: mailbox full;
            * sample:
            * The error that the other server returned was:
            * 550-5.7.1 Email quota exceeded.
            */
            elseif (preg_match("/email quota exceeded/i", $body, $match)) {
                $result['rule_cat'] = 'full';
                $result['rule_no']  = '0219';
            }

            /*
            * rule: mailbox full;
            * sample:
            * The error that the other server returned was:
            * 552-5.2.2 The email account that you tried to reach is over quota.
            */
            if (preg_match("/email.*?over quota/i", $body, $match)) {
                $result['rule_cat'] = 'full';
                $result['rule_no']  = '0219';
            }

            /*
            * rule: mailbox antispam;
            * sample:
            * The error that the other server returned was:
            * 550-5.7.1 Our system has detected an unusual rate of unsolicited mail originating from your IP address. To protect our users from spam,
            * mail sent from your IP address has been blocked.
            */
            elseif (preg_match("/unsolicited mail/i", $body, $match)) {
                $result['rule_cat'] = 'antispam';
                $result['rule_no']  = '0230';
            }

            /*
            * rule: mailbox antispam;
            * sample:
            * The error that the other server returned was:
            * 550-5.7.1 The user or domain that you are sending to (or from) has a policy that prohibited the mail that you sent.
            */
            elseif (preg_match("/policy that prohibited/i", $body, $match)) {
                $result['rule_cat'] = 'antispam';
                $result['rule_no']  = '0230';
            }

            /*
            * rule: mailbox oversize;
            * sample:
            * The error that the other server returned was:
            * 552-5.2.3 Your message exceeded Google's message size limits.
            */
            elseif (preg_match("/message size limits/i", $body, $match)) {
                $result['rule_cat'] = 'oversize';
                $result['rule_no']  = '0146';
            }
        }

        /*
        * rule: mailbox unknown;
        * sample:
        * xxxxx@yourdomain.com
        * no such address here
        */
        if (preg_match("/(\S+@\S+\w).*\n?.*no such address here/i", $body, $match)) {
            $result['rule_cat'] = 'unknown';
            $result['rule_no']  = '0237';
            $result['email']    = $match[1];
        }

        /*
        * <xxxxx@yourdomain.com>:
        * 111.111.111.111 does not like recipient.
        * Remote host said: 550 User unknown
        */
        elseif (preg_match("/<(\S+@\S+\w)>.*\n?.*\n?.*user unknown/i", $body, $match)) {
            $result['rule_cat'] = 'unknown';
            $result['rule_no']  = '0236';
            $result['email']    = $match[1];
        }

        /*
         * rule: mailbox unknown;
         * sample:
         * <xxxxx@yourdomain.com>:
         * Sorry, no mailbox here by that name. vpopmail (#5.1.1)
         */
        elseif (preg_match("/<(\S+@\S+\w)>.*\n?.*no mailbox/i", $body, $match)) {

            $result['rule_cat'] = 'unknown';
            $result['rule_no']  = '0157';
            $result['email']    = $match[1];
        }

       /*
        * rule: mailbox unknown;
        * sample:
        * xxxxx@yourdomain.com

        * local: Sorry, can't find user's mailbox. (#5.1.1)

        */
        elseif (preg_match("/(\S+@\S+\w)
.*\n?.*\n?.*can't find.*mailbox/i", $body, $match)) {

            $result['rule_cat'] = 'unknown';
            $result['rule_no']  = '0164';
            $result['email']    = $match[1];
        }

        /*
        * rule: mailbox unknown;
        * sample:
        *     ##########################################################
        *     #  This is an automated response from a mail delivery    #
        *     #  program.  Your message could not be delivered to      #
        *     #  the following address:                                #
        *     #                                                        #
        *     #      "|/usr/local/bin/mailfilt -u #dkms"               #
        *     #        (reason: Can't create output)                   #
        *     #        (expanded from: <xxxxx@yourdomain.com>)         #
        *     #                                                        #
        */
        elseif (preg_match("/Can't create output.*\n?.*<(\S+@\S+\w)>/i", $body, $match)) {
            $result['rule_cat'] = 'unknown';
            $result['rule_no']  = '0169';
            $result['email']    = $match[1];
        }

        /*
        * rule: mailbox unknown;
        * sample:
        * ????????????????:
        * xxxxx@yourdomain.com : ????, ?????.
        */
        elseif (preg_match("/(\S+@\S+\w).*=D5=CA=BA=C5=B2=BB=B4=E6=D4=DA/i", $body, $match)) {
            $result['rule_cat'] = 'unknown';
            $result['rule_no']  = '0174';
            $result['email']    = $match[1];
        }

        /*
        * rule: mailbox unknown;
        * sample:
        * xxxxx@yourdomain.com
        * Unrouteable address
        */
        elseif (preg_match("/(\S+@\S+\w).*\n?.*Unrouteable address/i", $body, $match)) {
            $result['rule_cat'] = 'unknown';
            $result['rule_no']  = '0179';
            $result['email']    = $match[1];
        }

        /*
        * rule: mailbox unknown;
        * sample:
        * Delivery to the following recipients failed.
        * xxxxx@yourdomain.com
        */
        elseif (preg_match("/delivery[^\n\r]+failed[ \S]*\s+(\S+@\S+\w)\s/is", $body, $match)) {
            $result['rule_cat'] = 'unknown';
            $result['rule_no']  = '0013';
            $result['email']    = $match[1];
        }

        /*
        * rule: mailbox error (Amazon SES);
        * sample:
        * An error occurred while trying to deliver the mail to the following recipients:
        * xxxxx@yourdomain.com
        */
        elseif (preg_match("/an\s+error\s+occurred\s+while\s+trying\s+to\s+deliver\s+the\s+mail\s+to\s+the\s+following\s+recipients:\r\n\s*(\S+@\S+\w)/is", $body, $match)) {
            $result['rule_cat'] = 'unknown';
            $result['rule_no']  = '0013';
            $result['bounce_type'] = 'hard';
            $result['remove']      = 1;
            $result['email']    = $match[1];
            $result['email'] = preg_replace("/Reporting\-MTA/","",$result['email']);
        }

        /*
        * rule: mailbox unknown;
        * sample:
        * A message that you sent could not be delivered to one or more of its^M
        * recipients. This is a permanent error. The following address(es) failed:^M
        * ^M
        * xxxxx@yourdomain.com^M
        * unknown local-part "xxxxx" in domain "yourdomain.com"^M
        */
        elseif (preg_match("/(\S+@\S+\w).*\n?.*unknown local-part/i", $body, $match)) {
            $result['rule_cat'] = 'unknown';
            $result['rule_no']  = '0232';
            $result['email']    = $match[1];
        }

        /*
        * rule: mailbox unknown;
        * sample:
        * <xxxxx@yourdomain.com>:^M
        * 111.111.111.11 does not like recipient.^M
        * Remote host said: 550 Invalid recipient: <xxxxx@yourdomain.com>^M
        */
        elseif (preg_match("/Invalid.*(?:alias|account|recipient|address|email|mailbox|user).*<(\S+@\S+\w)>/i", $body, $match)) {
            $result['rule_cat'] = 'unknown';
            $result['rule_no']  = '0233';
            $result['email']    = $match[1];
        }

        /*
        * rule: mailbox unknown;
        * sample:
        * Sent >>> RCPT TO: <xxxxx@yourdomain.com>^M
        * Received <<< 550 xxxxx@yourdomain.com... No such user^M
        * ^M
        * Could not deliver mail to this user.^M
        * xxxxx@yourdomain.com^M
        * *****************     End of message     ***************^M
        */
        elseif (preg_match("/\s(\S+@\S+\w).*No such.*(?:alias|account|recipient|address|email|mailbox|user)>/i", $body, $match)) {
            $result['rule_cat'] = 'unknown';
            $result['rule_no']  = '0234';
            $result['email']    = $match[1];
        }

        /*
        * rule: mailbox unknown;
        * sample:
        * <xxxxx@yourdomain.com>:^M
        * This address no longer accepts mail.
        */
        elseif (preg_match("/<(\S+@\S+\w)>.*\n?.*(?:alias|account|recipient|address|email|mailbox|user).*no.*accept.*mail>/i", $body, $match)) {
            $result['rule_cat'] = 'unknown';
            $result['rule_no']  = '0235';
            $result['email']    = $match[1];
        }

        /*
        * rule: full
        * sample 1:
        * <xxxxx@yourdomain.com>:
        * This account is over quota and unable to receive mail.
        * sample 2:
        * <xxxxx@yourdomain.com>:
        * Warning: undefined mail delivery mode: normal (ignored).
        * The users mailfolder is over the allowed quota (size). (#5.2.2)
        */
        elseif (preg_match("/<(\S+@\S+\w)>.*\n?.*\n?.*over.*quota/i", $body, $match)) {
            $result['rule_cat'] = 'full';
            $result['rule_no']  = '0182';
            $result['email']    = $match[1];
        }

        /*
        * rule: mailbox full;
        * sample:
        *   ----- Transcript of session follows -----
        * mail.local: /var/mail/2b/10/kellen.lee: Disc quota exceeded
        * 554 <xxxxx@yourdomain.com>... Service unavailable
        */
        elseif (preg_match("/quota exceeded.*\n?.*<(\S+@\S+\w)>/i", $body, $match)) {
            $result['rule_cat'] = 'full';
            $result['rule_no']  = '0126';
            $result['email']    = $match[1];
        }

        /*
        * rule: mailbox full;
        * sample:
        * Hi. This is the qmail-send program at 263.domain.com.
        * <xxxxx@yourdomain.com>:
        * - User disk quota exceeded. (#4.3.0)
        */
        elseif (preg_match("/<(\S+@\S+\w)>.*\n?.*quota exceeded/i", $body, $match)) {
            $result['rule_cat'] = 'full';
            $result['rule_no']  = '0158';
            $result['email']    = $match[1];
        }

        /*
        * rule: mailbox full;
        * sample:
        * xxxxx@yourdomain.com
        * mailbox is full (MTA-imposed quota exceeded while writing to file /mbx201/mbx011/A100/09/35/A1000935772/mail/.inbox):
        */
        elseif (preg_match("/\s(\S+@\S+\w)\s.*\n?.*mailbox.*full/i", $body, $match)) {
            $result['rule_cat'] = 'full';
            $result['rule_no']  = '0166';
            $result['email']    = $match[1];
        }

        /*
        * rule: mailbox full;
        * sample:
        * The message to xxxxx@yourdomain.com is bounced because : Quota exceed the hard limit
        */
        elseif (preg_match("/The message to (\S+@\S+\w)\s.*bounce.*Quota exceed/i", $body, $match)) {
            $result['rule_cat'] = 'full';
            $result['rule_no']  = '0168';
            $result['email']    = $match[1];
        }

        /*
        * rule: inactive
        * sample:
        * xxxxx@yourdomain.com

        * 553 user is inactive (eyou mta)
        */
        elseif (preg_match("/(\S+@\S+\w)
.*\n?.*\n?.*user is inactive/i", $body, $match)) {
            $result['rule_cat'] = 'inactive';
            $result['rule_no']  = '0171';
            $result['email']    = $match[1];
        }

        /*
        * rule: inactive
        * sample:
        * xxxxx@yourdomain.com [Inactive account]
        */
        elseif (preg_match("/(\S+@\S+\w).*inactive account/i", $body, $match)) {
            $result['rule_cat'] = 'inactive';
            $result['rule_no']  = '0181';
            $result['email']    = $match[1];
        }

        /*
        * rule: internal_error
        * sample:
        * <xxxxx@yourdomain.com>:
        * Unable to switch to /var/vpopmail/domains/domain.com: input/output error. (#4.3.0)
        */
        elseif (preg_match("/<(\S+@\S+\w)>.*\n?.*input\/output error/i", $body, $match)) {
            $result['rule_cat']    = 'internal_error';
            $result['rule_no']     = '0172';
            $result['bounce_type'] = 'hard';
            $result['remove']      = 1;
            $result['email']       = $match[1];
        }

        /*
        * rule: internal_error
        * sample:
        * <xxxxx@yourdomain.com>:
        * can not open new email file errno=13 file=/home/vpopmail/domains/fromc.com/0/domain/Maildir/tmp/1155254417.28358.mx05,S=212350
        */
        elseif (preg_match("/<(\S+@\S+\w)>.*\n?.*can not open new email file/i", $body, $match)) {
            $result['rule_cat']    = 'internal_error';
            $result['rule_no']     = '0173';
            $result['bounce_type'] = 'hard';
            $result['remove']      = 1;
            $result['email']       = $match[1];
        }

        /*
        * rule: defer
        * sample:
        * <xxxxx@yourdomain.com>:
        * 111.111.111.111 failed after I sent the message.
        * Remote host said: 451 mta283.mail.scd.yahoo.com Resources temporarily unavailable. Please try again later [#4.16.5].
        */
        elseif (preg_match("/<(\S+@\S+\w)>.*\n?.*\n?.*Resources temporarily unavailable/i", $body, $match)) {
            $result['rule_cat'] = 'defer';
            $result['rule_no']  = '0163';
            $result['email']    = $match[1];
        }

        /*
        * rule: autoreply
        * sample:
        * AutoReply message from xxxxx@yourdomain.com
        */
        elseif (preg_match("/^AutoReply message from (\S+@\S+\w)/i", $body, $match)) {
            $result['rule_cat'] = 'autoreply';
            $result['rule_no']  = '0167';
            $result['email']    = $match[1];
        }

        /*
        * rule: western chars only
        * sample:
        * <xxxxx@yourdomain.com>:
        * The user does not accept email in non-Western (non-Latin) character sets.
        */
        elseif (preg_match("/<(\S+@\S+\w)>.*\n?.*does not accept[^\r\n]*non-Western/i", $body, $match)) {
            $result['rule_cat'] = 'latin_only';
            $result['rule_no']  = '0043';
            $result['email']    = $match[1];
        }

        if ($result['rule_no'] == '0000') {
            if ($debug_mode) {
                echo 'Body:'.self::$bmh_newline.$body.self::$bmh_newline;
                echo self::$bmh_newline;
            }
        } else {
            if ($result['bounce_type'] === false) {
                $result['bounce_type'] = self::$rule_categories[$result['rule_cat']]['bounce_type'];
                $result['remove']      = self::$rule_categories[$result['rule_cat']]['remove'];
            }
        }

        return $result;
    }

    /**
     * Defined bounce parsing rules for standard DSN (Delivery Status Notification)
     *
     * @param string  $dsn_msg    human-readable explanation
     * @param string  $dsn_report delivery-status report
     * @param boolean $debug_mode show debug info. or not
     *
     * @return array    $result an array include the following fields: 'email', 'bounce_type','remove','rule_no','rule_cat'
     *                      if we could NOT detect the type of bounce, return rule_no = '0000'
     */
    static public function parseDsn($dsn_msg, $dsn_report, $debug_mode = false)
    {
        // initialize the result array
        $result      = array(
            'email'       => '',
            'bounce_type' => false,
            'remove'      => 0,
            'rule_cat'    => 'unrecognized',
            'rule_no'     => '0000'
        );
        $action      = false;
        $status_code = false;
        $diag_code   = false;

        // ======= parse $dsn_report ======
        // get the recipient email
        if (preg_match("/Original-Recipient: rfc822;(.*)/i", $dsn_report, $match)) {
            $email_arr = imap_rfc822_parse_adrlist($match[1], 'default.domain.name');
            if (isset($email_arr[0]->host) && $email_arr[0]->host != '.SYNTAX-ERROR.' && $email_arr[0]->host != 'default.domain.name') {
                $result['email'] = $email_arr[0]->mailbox.'@'.$email_arr[0]->host;
            }
        } else if (preg_match("/Final-Recipient: rfc822;(.*)/i", $dsn_report, $match)) {
            $email_arr = imap_rfc822_parse_adrlist($match[1], 'default.domain.name');
            if (isset($email_arr[0]->host) && $email_arr[0]->host != '.SYNTAX-ERROR.' && $email_arr[0]->host != 'default.domain.name') {
                $result['email'] = $email_arr[0]->mailbox.'@'.$email_arr[0]->host;
            }
        }

        if (preg_match("/Action: (.+)/i", $dsn_report, $match)) {
            $action = strtolower(trim($match[1]));
        }

        if (preg_match("/Status: ([0-9\.]+)/i", $dsn_report, $match)) {
            $status_code = $match[1];
        }

        // Could be multi-line , if the new line is beginning with SPACE or HTAB
        if (preg_match("/Diagnostic-Code:((?:[^\n]|\n[\t ])+)(?:\n[^\t ]|$)/is", $dsn_report, $match)) {
            $diag_code = $match[1];
        }
        // ======= rules ======
        if (empty($result['email'])) {
            /* email address is empty
             * rule: full
             * sample:   DSN Message only
             * User quota exceeded: SMTP <xxxxx@yourdomain.com>
             */
            if (preg_match("/quota exceed.*<(\S+@\S+\w)>/is", $dsn_msg, $match)) {
                $result['rule_cat'] = 'full';
                $result['rule_no']  = '0161';
                $result['email']    = $match[1];
            }
        } else {
            /* action could be one of them as RFC:1894
             * "failed" / "delayed" / "delivered" / "relayed" / "expanded"
             */
            switch ($action) {
                case 'failed':
                    /* rule: full
                     * sample:
                     * Diagnostic-Code: X-Postfix; me.domain.com platform: said: 552 5.2.2 Over
                     *   quota (in reply to RCPT TO command)
                     */
                    if (preg_match("/over.*quota/is", $diag_code)) {
                        $result['rule_cat'] = 'full';
                        $result['rule_no']  = '0105';
                    }

                    /* rule: full
                     * sample:
                     * Diagnostic-Code: SMTP; 552 Requested mailbox exceeds quota.
                     */
                    elseif (preg_match("/exceed.*quota/is", $diag_code)) {
                        $result['rule_cat'] = 'full';
                        $result['rule_no']  = '0129';
                    }

                    /* rule: full
                     * sample 1:
                     * Diagnostic-Code: smtp;552 5.2.2 This message is larger than the current system limit or the recipient's mailbox is full. Create a shorter message body or remove attachments and try sending it again.
                     * sample 2:
                     * Diagnostic-Code: X-Postfix; host mta5.us4.domain.com.int[111.111.111.111] said:
                     *   552 recipient storage full, try again later (in reply to RCPT TO command)
                     * sample 3:
                     * Diagnostic-Code: X-HERMES; host 127.0.0.1[127.0.0.1] said: 551 bounce as<the
                     *   destination mailbox <xxxxx@yourdomain.com> is full> queue as
                     *   100.1.ZmxEL.720k.1140313037.xxxxx@yourdomain.com (in reply to end of
                     *   DATA command)
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*full/is", $diag_code)) {
                        $result['rule_cat'] = 'full';
                        $result['rule_no']  = '0145';
                    }

                    /* rule: full
                     * sample:
                     * Diagnostic-Code: SMTP; 452 Insufficient system storage
                     */
                    elseif (preg_match("/Insufficient system storage/is", $diag_code)) {
                        $result['rule_cat'] = 'full';
                        $result['rule_no']  = '0134';
                    }

                    /* rule: full
                     * sample 1:
                     * Diagnostic-Code: X-Postfix; cannot append message to destination file^M
                     *   /var/mail/dale.me89g: error writing message: File too large^M
                     * sample 2:
                     * Diagnostic-Code: X-Postfix; cannot access mailbox /var/spool/mail/b8843022 for^M
                     *   user xxxxx. error writing message: File too large
                     */
                    elseif (preg_match("/File too large/is", $diag_code)) {
                        $result['rule_cat'] = 'full';
                        $result['rule_no']  = '0192';
                    }

                    /* rule: oversize
                     * sample:
                     * Diagnostic-Code: smtp;552 5.2.2 This message is larger than the current system limit or the recipient's mailbox is full. Create a shorter message body or remove attachments and try sending it again.
                     */
                    elseif (preg_match("/larger than.*limit/is", $diag_code)) {
                        $result['rule_cat'] = 'oversize';
                        $result['rule_no']  = '0146';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: X-Notes; User xxxxx (xxxxx@yourdomain.com) not listed in public Name & Address Book
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user)(.*)not(.*)list/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0103';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: smtp; 450 user path no exist
                     */
                    elseif (preg_match("/user path no exist/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0106';
                    }

                    /* rule: unknown
                     * sample 1:
                     * Diagnostic-Code: SMTP; 550 Relaying denied.
                     * sample 2:
                     * Diagnostic-Code: SMTP; 554 <xxxxx@yourdomain.com>: Relay access denied
                     * sample 3:
                     * Diagnostic-Code: SMTP; 550 relaying to <xxxxx@yourdomain.com> prohibited by administrator
                     */
                    elseif (preg_match("/Relay.*(?:denied|prohibited)/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0108';
                    }

                   /*rule: unknown
                    * sample:
                    * Diagnostic-Code: SMTP; 554 qq Sorry, no valid recipients (#5.1.3)
                    */
                    elseif (preg_match("/no.*valid.*(?:alias|account|recipient|address|email|mailbox|user)/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0185';
                    }

                    /* rule: unknown
                     * sample 1:
                     * Diagnostic-Code: SMTP; 550 «Dªk¦a§} - invalid address (#5.5.0)
                     * sample 2:
                     * Diagnostic-Code: SMTP; 550 Invalid recipient: <xxxxx@yourdomain.com>
                     * sample 3:
                     * Diagnostic-Code: SMTP; 550 <xxxxx@yourdomain.com>: Invalid User
                     */
                    elseif (preg_match("/Invalid.*(?:alias|account|recipient|address|email|mailbox|user)/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0111';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 554 delivery error: dd Sorry your message to xxxxx@yourdomain.com cannot be delivered. This account has been disabled or discontinued [#102]. - mta173.mail.tpe.domain.com
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*(?:disabled|discontinued)/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0114';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 554 delivery error: dd This user doesn't have a domain.com account (www.xxxxx@yourdomain.com) [0] - mta134.mail.tpe.domain.com
                     */
                    elseif (preg_match("/user doesn't have.*account/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0127';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 550 5.1.1 unknown or illegal alias: xxxxx@yourdomain.com
                     */
                    elseif (preg_match("/(?:unknown|illegal).*(?:alias|account|recipient|address|email|mailbox|user)/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0128';
                    }

                    /* rule: unknown
                     * sample 1:
                     * Diagnostic-Code: SMTP; 450 mailbox unavailable.
                     * sample 2:
                     * Diagnostic-Code: SMTP; 550 5.7.1 Requested action not taken: mailbox not available
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*(?:un|not\s+)available/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0122';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 553 sorry, no mailbox here by that name (#5.7.1)
                     */
                    elseif (preg_match("/no (?:alias|account|recipient|address|email|mailbox|user)/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0123';
                    }

                    /* rule: unknown
                     * sample 1:
                     * Diagnostic-Code: SMTP; 550 User (xxxxx@yourdomain.com) unknown.
                     * sample 2:
                     * Diagnostic-Code: SMTP; 553 5.3.0 <xxxxx@yourdomain.com>... Addressee unknown, relay=[111.111.111.000]
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*unknown/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0125';
                    }

                    /* rule: unknown
                     * sample 1:
                     * Diagnostic-Code: SMTP; 550 user disabled
                     * sample 2:
                     * Diagnostic-Code: SMTP; 452 4.2.1 mailbox temporarily disabled: xxxxx@yourdomain.com
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*disabled/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0133';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 550 <xxxxx@yourdomain.com>: Recipient address rejected: No such user (xxxxx@yourdomain.com)
                     */
                    elseif (preg_match("/No such (?:alias|account|recipient|address|email|mailbox|user)/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0143';
                    }

                    /* rule: unknown
                     * sample 1:
                     * Diagnostic-Code: SMTP; 550 MAILBOX NOT FOUND
                     * sample 2:
                     * Diagnostic-Code: SMTP; 550 Mailbox ( xxxxx@yourdomain.com ) not found or inactivated
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*NOT FOUND/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0136';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: X-Postfix; host m2w-in1.domain.com[111.111.111.000] said: 551
                     * <xxxxx@yourdomain.com> is a deactivated mailbox (in reply to RCPT TO
                     * command)
                     */
                    elseif (preg_match("/deactivated (?:alias|account|recipient|address|email|mailbox|user)/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0138';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 550 <xxxxx@yourdomain.com> recipient rejected
                     * ...
                     * <<< 550 <xxxxx@yourdomain.com> recipient rejected
                     * 550 5.1.1 xxxxx@yourdomain.com... User unknown
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*reject/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0148';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: smtp; 5.x.0 - Message bounced by administrator  (delivery attempts: 0)
                     */
                    elseif (preg_match("/bounce.*administrator/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0151';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 550 <maxqin> is now disabled with MTA service.
                     */
                    elseif (preg_match("/<.*>.*disabled/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0152';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 551 not our customer
                     */
                    elseif (preg_match("/not our customer/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0154';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: smtp; 5.1.0 - Unknown address error 540-'Error: Wrong recipients' (delivery attempts: 0)
                     */
                    elseif (preg_match("/Wrong (?:alias|account|recipient|address|email|mailbox|user)/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0159';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: smtp; 5.1.0 - Unknown address error 540-'Error: Wrong recipients' (delivery attempts: 0)
                     * sample 2:
                     * Diagnostic-Code: SMTP; 501 #5.1.1 bad address xxxxx@yourdomain.com
                     */
                    elseif (preg_match("/(?:unknown|bad).*(?:alias|account|recipient|address|email|mailbox|user)/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0160';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 550 Command RCPT User <xxxxx@yourdomain.com> not OK
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*not OK/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0186';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 550 5.7.1 Access-Denied-XM.SSR-001
                     */
                    elseif (preg_match("/Access.*Denied/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0189';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 550 5.1.1 <xxxxx@yourdomain.com>... email address lookup in domain map failed^M
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*lookup.*fail/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0195';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 550 User not a member of domain: <xxxxx@yourdomain.com>^M
                     */
                    elseif (preg_match("/(?:recipient|address|email|mailbox|user).*not.*member of domain/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0198';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 550-"The recipient cannot be verified.  Please check all recipients of this^M
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*cannot be verified/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0202';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 550 Unable to relay for xxxxx@yourdomain.com
                     */
                    elseif (preg_match("/Unable to relay/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0203';
                    }

                    /* rule: unknown
                     * sample 1:
                     * Diagnostic-Code: SMTP; 550 xxxxx@yourdomain.com:user not exist
                     * sample 2:
                     * Diagnostic-Code: SMTP; 550 sorry, that recipient doesn't exist (#5.7.1)
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*(?:n't|not) exist/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0205';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 550-I'm sorry but xxxxx@yourdomain.com does not have an account here. I will not
                     */
                    elseif (preg_match("/not have an account/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0207';
                    }

                    /* rule: unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 550 This account is not allowed...xxxxx@yourdomain.com
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*is not allowed/is", $diag_code)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0220';
                    }

                    /* rule: inactive
                     * sample:
                     * Diagnostic-Code: SMTP; 550 <xxxxx@yourdomain.com>: inactive user
                     */
                    elseif (preg_match("/inactive.*(?:alias|account|recipient|address|email|mailbox|user)/is", $diag_code)) {
                        $result['rule_cat'] = 'inactive';
                        $result['rule_no']  = '0135';
                    }

                    /* rule: inactive
                     * sample:
                     * Diagnostic-Code: SMTP; 550 xxxxx@yourdomain.com Account Inactive
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*Inactive/is", $diag_code)) {
                        $result['rule_cat'] = 'inactive';
                        $result['rule_no']  = '0155';
                    }

                    /* rule: inactive
                     * sample:
                     * Diagnostic-Code: SMTP; 550 <xxxxx@yourdomain.com>: Recipient address rejected: Account closed due to inactivity. No forwarding information is available.
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user) closed due to inactivity/is", $diag_code)) {
                        $result['rule_cat'] = 'inactive';
                        $result['rule_no']  = '0170';
                    }

                    /* rule: inactive
                     * sample:
                     * Diagnostic-Code: SMTP; 550 <xxxxx@yourdomain.com>... User account not activated
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user) not activated/is", $diag_code)) {
                        $result['rule_cat'] = 'inactive';
                        $result['rule_no']  = '0177';
                    }

                    /* rule: inactive
                     * sample 1:
                     * Diagnostic-Code: SMTP; 550 User suspended
                     * sample 2:
                     * Diagnostic-Code: SMTP; 550 account expired
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*(?:suspend|expire)/is", $diag_code)) {
                        $result['rule_cat'] = 'inactive';
                        $result['rule_no']  = '0183';
                    }

                    /* rule: inactive
                     * sample:
                     * Diagnostic-Code: SMTP; 553 5.3.0 <xxxxx@yourdomain.com>... Recipient address no longer exists
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*no longer exist/is", $diag_code)) {
                        $result['rule_cat'] = 'inactive';
                        $result['rule_no']  = '0184';
                    }

                    /* rule: inactive
                     * sample:
                     * Diagnostic-Code: SMTP; 553 VS10-RT Possible forgery or deactivated due to abuse (#5.1.1) 111.111.111.211^M
                     */
                    elseif (preg_match("/(?:forgery|abuse)/is", $diag_code)) {
                        $result['rule_cat'] = 'inactive';
                        $result['rule_no']  = '0196';
                    }

                    /* rule: inactive
                     * sample:
                     * Diagnostic-Code: SMTP; 553 mailbox xxxxx@yourdomain.com is restricted
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*restrict/is", $diag_code)) {
                        $result['rule_cat'] = 'inactive';
                        $result['rule_no']  = '0209';
                    }

                    /* rule: inactive
                     * sample:
                     * Diagnostic-Code: SMTP; 550 <xxxxx@yourdomain.com>: User status is locked.
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*locked/is", $diag_code)) {
                        $result['rule_cat'] = 'inactive';
                        $result['rule_no']  = '0228';
                    }

                    /* rule: user_reject
                     * sample:
                     * Diagnostic-Code: SMTP; 553 User refused to receive this mail.
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user) refused/is", $diag_code)) {
                        $result['rule_cat'] = 'user_reject';
                        $result['rule_no']  = '0156';
                    }

                    /* rule: user_reject
                     * sample:
                     * Diagnostic-Code: SMTP; 501 xxxxx@yourdomain.com Sender email is not in my domain
                     */
                    elseif (preg_match("/sender.*not/is", $diag_code)) {
                        $result['rule_cat'] = 'user_reject';
                        $result['rule_no']  = '0206';
                    }

                    /* rule: command_reject
                     * sample:
                     * Diagnostic-Code: SMTP; 554 Message refused
                     */
                    elseif (preg_match("/Message refused/is", $diag_code)) {
                        $result['rule_cat'] = 'command_reject';
                        $result['rule_no']  = '0175';
                    }

                    /* rule: command_reject
                     * sample:
                     * Diagnostic-Code: SMTP; 550 5.0.0 <xxxxx@yourdomain.com>... No permit
                     */
                    elseif (preg_match("/No permit/is", $diag_code)) {
                        $result['rule_cat'] = 'command_reject';
                        $result['rule_no']  = '0190';
                    }

                    /* rule: command_reject
                     * sample:
                     * Diagnostic-Code: SMTP; 553 sorry, that domain isn't in my list of allowed rcpthosts (#5.5.3 - chkuser)
                     */
                    elseif (preg_match("/domain isn't in.*allowed rcpthost/is", $diag_code)) {
                        $result['rule_cat'] = 'command_reject';
                        $result['rule_no']  = '0191';
                    }

                    /* rule: command_reject
                     * sample:
                     * Diagnostic-Code: SMTP; 553 AUTH FAILED - xxxxx@yourdomain.com^M
                     */
                    elseif (preg_match("/AUTH FAILED/is", $diag_code)) {
                        $result['rule_cat'] = 'command_reject';
                        $result['rule_no']  = '0197';
                    }

                    /* rule: command_reject
                     * sample 1:
                     * Diagnostic-Code: SMTP; 550 relay not permitted^M
                     * sample 2:
                     * Diagnostic-Code: SMTP; 530 5.7.1 Relaying not allowed: xxxxx@yourdomain.com
                     */
                    elseif (preg_match("/relay.*not.*(?:permit|allow)/is", $diag_code)) {
                        $result['rule_cat'] = 'command_reject';
                        $result['rule_no']  = '0201';
                    }

                    /* rule: command_reject
                     * sample:
                     *
                     * Diagnostic-Code: SMTP; 550 not local host domain.com, not a gateway
                     */
                    elseif (preg_match("/not local host/is", $diag_code)) {
                        $result['rule_cat'] = 'command_reject';
                        $result['rule_no']  = '0204';
                    }

                    /* rule: command_reject
                     * sample:
                     * Diagnostic-Code: SMTP; 500 Unauthorized relay msg rejected
                     */
                    elseif (preg_match("/Unauthorized relay/is", $diag_code)) {
                        $result['rule_cat'] = 'command_reject';
                        $result['rule_no']  = '0215';
                    }

                    /* rule: command_reject
                     * sample:
                     * Diagnostic-Code: SMTP; 554 Transaction failed
                     */
                    elseif (preg_match("/Transaction.*fail/is", $diag_code)) {
                        $result['rule_cat'] = 'command_reject';
                        $result['rule_no']  = '0221';
                    }

                    /* rule: command_reject
                     * sample:
                     * Diagnostic-Code: smtp;554 5.5.2 Invalid data in message
                     */
                    elseif (preg_match("/Invalid data/is", $diag_code)) {
                        $result['rule_cat'] = 'command_reject';
                        $result['rule_no']  = '0223';
                    }

                    /* rule: command_reject
                     * sample:
                     * Diagnostic-Code: SMTP; 550 Local user only or Authentication mechanism
                     */
                    elseif (preg_match("/Local user only/is", $diag_code)) {
                        $result['rule_cat'] = 'command_reject';
                        $result['rule_no']  = '0224';
                    }

                    /* rule: command_reject
                     * sample:
                     * Diagnostic-Code: SMTP; 550-ds176.domain.com [111.111.111.211] is currently not permitted to
                     * relay through this server. Perhaps you have not logged into the pop/imap
                     * server in the last 30 minutes or do not have SMTP Authentication turned on
                     * in your email client.
                     */
                    elseif (preg_match("/not.*permit.*to/is", $diag_code)) {
                        $result['rule_cat'] = 'command_reject';
                        $result['rule_no']  = '0225';
                    }

                    /* rule: content_reject
                     * sample:
                     * Diagnostic-Code: SMTP; 550 Content reject. FAAAANsG60M9BmDT.1
                     */
                    elseif (preg_match("/Content reject/is", $diag_code)) {
                        $result['rule_cat'] = 'content_reject';
                        $result['rule_no']  = '0165';
                    }

                    /* rule: content_reject
                     * sample:
                     * Diagnostic-Code: SMTP; 552 MessageWall: MIME/REJECT: Invalid structure
                     */
                    elseif (preg_match("/MIME\/REJECT/is", $diag_code)) {
                        $result['rule_cat'] = 'content_reject';
                        $result['rule_no']  = '0212';
                    }

                    /* rule: content_reject
                     * sample:
                     * Diagnostic-Code: smtp; 554 5.6.0 Message with invalid header rejected, id=13462-01 - MIME error: error: UnexpectedBound: part didn't end with expected boundary [in multipart message]; EOSToken: EOF; EOSType: EOF
                     */
                    elseif (preg_match("/MIME error/is", $diag_code)) {
                        $result['rule_cat'] = 'content_reject';
                        $result['rule_no']  = '0217';
                    }

                    /* rule: content_reject
                     * sample:
                     * Diagnostic-Code: SMTP; 553 Mail data refused by AISP, rule [169648].
                     */
                    elseif (preg_match("/Mail data refused.*AISP/is", $diag_code)) {
                        $result['rule_cat'] = 'content_reject';
                        $result['rule_no']  = '0218';
                    }

                    /* rule: dns_unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 550 Host unknown
                     */
                    elseif (preg_match("/Host unknown/is", $diag_code)) {
                        $result['rule_cat'] = 'dns_unknown';
                        $result['rule_no']  = '0130';
                    }

                    /* rule: dns_unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 553 Specified domain is not allowed.
                     */
                    elseif (preg_match("/Specified domain.*not.*allow/is", $diag_code)) {
                        $result['rule_cat'] = 'dns_unknown';
                        $result['rule_no']  = '0180';
                    }

                    /* rule: dns_unknown
                     * sample:
                     * Diagnostic-Code: X-Postfix; delivery temporarily suspended: connect to
                     * 111.111.11.112[111.111.11.112]: No route to host
                     */
                    elseif (preg_match("/No route to host/is", $diag_code)) {
                        $result['rule_cat'] = 'dns_unknown';
                        $result['rule_no']  = '0188';
                    }

                    /* rule: dns_unknown
                     * sample:
                     * Diagnostic-Code: SMTP; 550 unrouteable address
                     */
                    elseif (preg_match("/unrouteable address/is", $diag_code)) {
                        $result['rule_cat'] = 'dns_unknown';
                        $result['rule_no']  = '0208';
                    }

                    /* rule: defer
                     * sample:
                     * Diagnostic-Code: SMTP; 451 System(u) busy, try again later.
                     */
                    elseif (preg_match("/System.*busy/is", $diag_code)) {
                        $result['rule_cat'] = 'defer';
                        $result['rule_no']  = '0112';
                    }

                    /* rule: defer
                     * sample:
                     * Diagnostic-Code: SMTP; 451 mta172.mail.tpe.domain.com Resources temporarily unavailable. Please try again later.  [#4.16.4:70].
                     */
                    elseif (preg_match("/Resources temporarily unavailable/is", $diag_code)) {
                        $result['rule_cat'] = 'defer';
                        $result['rule_no']  = '0116';
                    }

                    /* rule: antispam, deny ip
                     * sample:
                     * Diagnostic-Code: SMTP; 554 sender is rejected: 0,mx20,wKjR5bDrnoM2yNtEZVAkBg==.32467S2
                     */
                    elseif (preg_match("/sender is rejected/is", $diag_code)) {
                        $result['rule_cat'] = 'antispam';
                        $result['rule_no']  = '0101';
                    }

                    /* rule: antispam, deny ip
                     * sample:
                     * Diagnostic-Code: SMTP; 554 <unknown[111.111.111.000]>: Client host rejected: Access denied
                     */
                    elseif (preg_match("/Client host rejected/is", $diag_code)) {
                        $result['rule_cat'] = 'antispam';
                        $result['rule_no']  = '0102';
                    }

                    /* rule: antispam, mismatch ip
                     * sample:
                     * Diagnostic-Code: SMTP; 554 Connection refused(mx). MAIL FROM [xxxxx@yourdomain.com] mismatches client IP [111.111.111.000].
                     */
                    elseif (preg_match("/MAIL FROM(.*)mismatches client IP/is", $diag_code)) {
                        $result['rule_cat'] = 'antispam';
                        $result['rule_no']  = '0104';
                    }

                    /* rule: antispam, deny ip
                     * sample:
                     * Diagnostic-Code: SMTP; 554 Please visit http:// antispam.domain.com/denyip.php?IP=111.111.111.000 (#5.7.1)
                     */
                    elseif (preg_match("/denyip/is", $diag_code)) {
                        $result['rule_cat'] = 'antispam';
                        $result['rule_no']  = '0144';
                    }

                    /* rule: antispam, deny ip
                     * sample:
                     * Diagnostic-Code: SMTP; 554 Service unavailable; Client host [111.111.111.211] blocked using dynablock.domain.com; Your message could not be delivered due to complaints we received regarding the IP address you're using or your ISP. See http:// blackholes.domain.com/ Error: WS-02^M
                     */
                    elseif (preg_match("/client host.*blocked/is", $diag_code)) {
                        $result['rule_cat'] = 'antispam';
                        $result['rule_no']  = '0201';
                    }

                    /* rule: antispam, reject
                     * sample:
                     * Diagnostic-Code: SMTP; 550 Requested action not taken: mail IsCNAPF76kMDARUY.56621S2 is rejected,mx3,BM
                     */
                    elseif (preg_match("/mail.*reject/is", $diag_code)) {
                        $result['rule_cat'] = 'antispam';
                        $result['rule_no']  = '0147';
                    }

                    /* rule: antispam
                     * sample:
                     * Diagnostic-Code: SMTP; 552 sorry, the spam message is detected (#5.6.0)
                     */
                    elseif (preg_match("/spam.*detect/is", $diag_code)) {
                        $result['rule_cat'] = 'antispam';
                        $result['rule_no']  = '0162';
                    }

                    /* rule: antispam
                     * sample:
                     * Diagnostic-Code: SMTP; 554 5.7.1 Rejected as Spam see: http:// rejected.domain.com/help/spam/rejected.html
                     */
                    elseif (preg_match("/reject.*spam/is", $diag_code)) {
                        $result['rule_cat'] = 'antispam';
                        $result['rule_no']  = '0216';
                    }

                    /* rule: antispam
                     * sample:
                     * Diagnostic-Code: SMTP; 553 5.7.1 <xxxxx@yourdomain.com>... SpamTrap=reject mode, dsn=5.7.1, Message blocked by BOX Solutions (www.domain.com) SpamTrap Technology, please contact the domain.com site manager for help: (ctlusr8012).^M
                     */
                    elseif (preg_match("/SpamTrap/is", $diag_code)) {
                        $result['rule_cat'] = 'antispam';
                        $result['rule_no']  = '0200';
                    }

                    /* rule: antispam, mailfrom mismatch
                     * sample:
                     * Diagnostic-Code: SMTP; 550 Verify mailfrom failed,blocked
                     */
                    elseif (preg_match("/Verify mailfrom failed/is", $diag_code)) {
                        $result['rule_cat'] = 'antispam';
                        $result['rule_no']  = '0210';
                    }

                    /* rule: antispam, mailfrom mismatch
                     * sample:
                     * Diagnostic-Code: SMTP; 550 Error: MAIL FROM is mismatched with message header from address!
                     */
                    elseif (preg_match("/MAIL.*FROM.*mismatch/is", $diag_code)) {
                        $result['rule_cat'] = 'antispam';
                        $result['rule_no']  = '0226';
                    }

                    /* rule: antispam
                     * sample:
                     * Diagnostic-Code: SMTP; 554 5.7.1 Message scored too high on spam scale.  For help, please quote incident ID 22492290.
                     */
                    elseif (preg_match("/spam scale/is", $diag_code)) {
                        $result['rule_cat'] = 'antispam';
                        $result['rule_no']  = '0211';
                    }

                    /* rule: antispam
                     * sample:
                     * Diagnostic-Code: SMTP; 554 5.7.1 reject: Client host bypassing service provider's mail relay: ds176.domain.com
                     8?
                    elseif (preg_match ("/Client host bypass/is",$diag_code)) {
                      $result['rule_cat']    = 'antispam';
                      $result['rule_no']     = '0229';
                    }
                    /* rule: antispam
                     * sample:
                     * Diagnostic-Code: SMTP; 550 sorry, it seems as a junk mail
                     */
                    elseif (preg_match("/junk mail/is", $diag_code)) {
                        $result['rule_cat'] = 'antispam';
                        $result['rule_no']  = '0230';
                    }

                    /* rule: antispam
                     * sample:
                     * Diagnostic-Code: SMTP; 553-Message filtered. Please see the FAQs section on spam
                     */
                    elseif (preg_match("/message filtered/is", $diag_code)) {
                        $result['rule_cat'] = 'antispam';
                        $result['rule_no']  = '0227';
                    }

                    /* rule: antispam, subject filter
                     * sample:
                     * Diagnostic-Code: SMTP; 554 5.7.1 The message from (<xxxxx@yourdomain.com>) with the subject of ( *(ca2639) 7|-{%2E* : {2"(%EJ;y} (SBI$#$@<K*:7s1!=l~) matches a profile the Internet community may consider spam. Please revise your message before resending.
                     */
                    elseif (preg_match("/subject.*consider.*spam/is", $diag_code)) {
                        $result['rule_cat'] = 'antispam';
                        $result['rule_no']  = '0222';
                    }

                    /* rule: internal_error
                     * sample:
                     * Diagnostic-Code: SMTP; 451 Temporary local problem - please try later
                     */
                    elseif (preg_match("/Temporary local problem/is", $diag_code)) {
                        $result['rule_cat'] = 'internal_error';
                        $result['rule_no']  = '0142';
                    }

                    /* rule: internal_error
                     * sample:
                     * Diagnostic-Code: SMTP; 553 5.3.5 system config error
                     */
                    elseif (preg_match("/system config error/is", $diag_code)) {
                        $result['rule_cat'] = 'internal_error';
                        $result['rule_no']  = '0153';
                    }

                    /* rule: delayed
                     * sample:
                     * Diagnostic-Code: X-Postfix; delivery temporarily suspended: conversation with^M
                     * 111.111.111.11[111.111.111.11] timed out while sending end of data -- message may be^M
                     * sent more than once
                     */
                    elseif (preg_match("/delivery.*suspend/is", $diag_code)) {
                        $result['rule_cat'] = 'delayed';
                        $result['rule_no']  = '0213';
                    }

                    // =========== rules based on the dsn_msg ===============
                    /* rule: unknown
                     * sample:
                     * ----- The following addresses had permanent fatal errors -----
                     * <xxxxx@yourdomain.com>
                     * ----- Transcript of session follows -----
                     * ... while talking to mta1.domain.com.:
                     * >>> DATA
                     * <<< 503 All recipients are invalid
                     * 554 5.0.0 Service unavailable
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user)(.*)invalid/i", $dsn_msg)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0107';
                    }

                    /* rule: unknown
                     * sample:
                     * ----- Transcript of session follows -----
                     * xxxxx@yourdomain.com... Deferred: No such file or directory
                     */
                    elseif (preg_match("/Deferred.*No such.*(?:file|directory)/i", $dsn_msg)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0141';
                    }

                    /* rule: unknown
                     * sample:
                     * Failed to deliver to '<xxxxx@yourdomain.com>'^M
                     * LOCAL module(account xxxx) reports:^M
                     * mail receiving disabled^M
                     */
                    elseif (preg_match("/mail receiving disabled/i", $dsn_msg)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0194';
                    }

                    /* rule: unknown
                     * sample:
                     * - These recipients of your message have been processed by the mail server:^M
                     * xxxxx@yourdomain.com; Failed; 5.1.1 (bad destination mailbox address)
                     */
                    elseif (preg_match("/bad.*(?:alias|account|recipient|address|email|mailbox|user)/i", $dsn_msg)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '227';
                    }

                    /* rule: full
                     * sample 1:
                     * This Message was undeliverable due to the following reason:
                     * The user(s) account is temporarily over quota.
                     * <xxxxx@yourdomain.com>
                     * sample 2:
                     *  Recipient address: xxxxx@yourdomain.com
                     *  Reason: Over quota
                     */
                    elseif (preg_match("/over.*quota/i", $dsn_msg)) {
                        $result['rule_cat'] = 'full';
                        $result['rule_no']  = '0131';
                    }

                    /* rule: full
                     * sample:
                     * Sorry the recipient quota limit is exceeded.
                     * This message is returned as an error.
                     */
                    elseif (preg_match("/quota.*exceeded/i", $dsn_msg)) {
                        $result['rule_cat'] = 'full';
                        $result['rule_no']  = '0150';
                    }

                    /* rule: full
                     * sample:
                     * The user to whom this message was addressed has exceeded the allowed mailbox
                     * quota. Please resend the message at a later time.
                     */
                    elseif (preg_match("/exceed.*\n?.*quota/i", $dsn_msg)) {
                        $result['rule_cat'] = 'full';
                        $result['rule_no']  = '0187';
                    }

                    /* rule: full
                     * sample 1:
                     * Failed to deliver to '<xxxxx@yourdomain.com>'
                     * LOCAL module(account xxxxxx) reports:
                     * account is full (quota exceeded)
                     * sample 2:
                     * Error in fabiomod_sql_glob_init: no data source specified - database access disabled
                     * [Fri Feb 17 23:29:38 PST 2006] full error for caltsmy:
                     * that member's mailbox is full
                     * 550 5.0.0 <xxxxx@yourdomain.com>... Can't create output
                     */
                    elseif (preg_match("/(?:alias|account|recipient|address|email|mailbox|user).*full/i", $dsn_msg)) {
                        $result['rule_cat'] = 'full';
                        $result['rule_no']  = '0132';
                    }

                    /* rule: full
                     * sample:
                     * gaosong "(0), ErrMsg=Mailbox space not enough (space limit is 10240KB)
                     */
                    elseif (preg_match("/space.*not.*enough/i", $dsn_msg)) {
                        $result['rule_cat'] = 'full';
                        $result['rule_no']  = '0219';
                    }

                    /* rule: defer
                     * sample 1:
                     * ----- Transcript of session follows -----
                     * xxxxx@yourdomain.com... Deferred: Connection refused by nomail.tpe.domain.com.
                     * Message could not be delivered for 5 days
                     * Message will be deleted from queue
                     * sample 2:
                     * 451 4.4.1 reply: read error from www.domain.com.
                     * xxxxx@yourdomain.com... Deferred: Connection reset by www.domain.com.
                     */
                    elseif (preg_match("/Deferred.*Connection (?:refused|reset)/i", $dsn_msg)) {
                        $result['rule_cat'] = 'defer';
                        $result['rule_no']  = '0115';
                    }

                    /* rule: dns_unknown
                     * sample:
                     * ----- The following addresses had permanent fatal errors -----
                     * Tan XXXX SSSS <xxxxx@yourdomain..com>
                     * ----- Transcript of session follows -----
                     * 553 5.1.2 XXXX SSSS <xxxxx@yourdomain..com>... Invalid host name
                     */
                    elseif (preg_match("/Invalid host name/i", $dsn_msg)) {
                        $result['rule_cat'] = 'dns_unknown';
                        $result['rule_no']  = '0109';
                    }

                    /* rule: dns_unknown
                     * sample:
                     * ----- Transcript of session follows -----
                     * xxxxx@yourdomain.com... Deferred: mail.domain.com.: No route to host
                     */
                    elseif (preg_match("/Deferred.*No route to host/i", $dsn_msg)) {
                        $result['rule_cat'] = 'dns_unknown';
                        $result['rule_no']  = '0109';
                    }

                    /* rule: dns_unknown
                     * sample:
                     * ----- Transcript of session follows -----
                     * 550 5.1.2 xxxxx@yourdomain.com... Host unknown (Name server: .: no data known)
                     */
                    elseif (preg_match("/Host unknown/i", $dsn_msg)) {
                        $result['rule_cat'] = 'dns_unknown';
                        $result['rule_no']  = '0140';
                    }

                    /* rule: dns_unknown
                     * sample:
                     * ----- Transcript of session follows -----
                     * 451 HOTMAIL.com.tw: Name server timeout
                     * Message could not be delivered for 5 days
                     * Message will be deleted from queue
                     */
                    elseif (preg_match("/Name server timeout/i", $dsn_msg)) {
                        $result['rule_cat'] = 'dns_unknown';
                        $result['rule_no']  = '0118';
                    }

                    /* rule: dns_unknown
                     * sample:
                     * ----- Transcript of session follows -----
                     * xxxxx@yourdomain.com... Deferred: Connection timed out with hkfight.com.
                     * Message could not be delivered for 5 days
                     * Message will be deleted from queue
                     */
                    elseif (preg_match("/Deferred.*Connection.*tim(?:e|ed).*out/i", $dsn_msg)) {
                        $result['rule_cat'] = 'dns_unknown';
                        $result['rule_no']  = '0119';
                    }

                    /* rule: dns_unknown
                     * sample:
                     * ----- Transcript of session follows -----
                     * xxxxx@yourdomain.com... Deferred: Name server: domain.com.: host name lookup failure
                     */
                    elseif (preg_match("/Deferred.*host name lookup failure/i", $dsn_msg)) {
                        $result['rule_cat'] = 'dns_unknown';
                        $result['rule_no']  = '0121';
                    }

                    /* rule: dns_loop
                     * sample:
                     * ----- Transcript of session follows -----^M
                     * 554 5.0.0 MX list for znet.ws. points back to mail01.domain.com^M
                     * 554 5.3.5 Local configuration error^M
                     */
                    elseif (preg_match("/MX list.*point.*back/i", $dsn_msg)) {
                        $result['rule_cat'] = 'dns_loop';
                        $result['rule_no']  = '0199';
                    }

                    /* rule: internal_error
                     * sample:
                     * ----- Transcript of session follows -----
                     * 451 4.0.0 I/O error
                     */
                    elseif (preg_match("/I\/O error/i", $dsn_msg)) {
                        $result['rule_cat'] = 'internal_error';
                        $result['rule_no']  = '0120';
                    }

                    /* rule: internal_error
                     * sample:
                     * Failed to deliver to 'xxxxx@yourdomain.com'^M
                     * SMTP module(domain domain.com) reports:^M
                     * connection with mx1.mail.domain.com is broken^M
                     */
                    elseif (preg_match("/connection.*broken/i", $dsn_msg)) {
                        $result['rule_cat'] = 'internal_error';
                        $result['rule_no']  = '0231';
                    }

                    /* rule: other
                     * sample:
                     * Delivery to the following recipients failed.
                     * xxxxx@yourdomain.com
                     */
                    elseif (preg_match("/Delivery to the following recipients failed.*\n.*\n.*".$result['email']."/i", $dsn_msg)) {
                        $result['rule_cat'] = 'other';
                        $result['rule_no']  = '0176';
                    }

                    // Followings are wind-up rule: must be the last one
                    //   many other rules msg end up with "550 5.1.1 ... User unknown"
                    //   many other rules msg end up with "554 5.0.0 Service unavailable"

                    /* rule: unknown
                     * sample 1:
                     * ----- The following addresses had permanent fatal errors -----^M
                     * <xxxxx@yourdomain.com>^M
                     * (reason: User unknown)^M
                     * sample 2:
                     * 550 5.1.1 xxxxx@yourdomain.com... User unknown^M
                     */
                    elseif (preg_match("/User unknown/i", $dsn_msg)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0193';
                    }

                    /* rule: unknown
                     * sample:
                     * 554 5.0.0 Service unavailable
                     */
                    elseif (preg_match("/Service unavailable/i", $dsn_msg)) {
                        $result['rule_cat'] = 'unknown';
                        $result['rule_no']  = '0214';
                    }
                    break;
                case 'delayed':
                    $result['rule_cat'] = 'delayed';
                    $result['rule_no']  = '0110';
                    break;
                case 'delivered':
                case 'relayed':
                case 'expanded': // unhandled cases
                    break;
                default :
                    break;
            }
        }

        if ($result['rule_no'] == '0000') {
            if ($debug_mode) {
                $result['debug'] = array(
                    'email '          => $result['email'].self::$bmh_newline,
                    'Action '         => $action.self::$bmh_newline,
                    'Status '         => $status_code.self::$bmh_newline,
                    'Diagnostic-Code' => $diag_code.self::$bmh_newline,
                    'DSN Message'     => $dsn_msg.self::$bmh_newline
                );
            }
        } else {
            if ($result['bounce_type'] === false) {
                $result['bounce_type'] = self::$rule_categories[$result['rule_cat']]['bounce_type'];
                $result['remove']      = self::$rule_categories[$result['rule_cat']]['remove'];
            }
        }

        return $result;
    }
}


text:
using NUnit.Framework;
using ServiceStack.FluentValidation;
using ServiceStack.Webhooks.Properties;
using ServiceStack.Webhooks.ServiceModel;
using ServiceStack.Webhooks.ServiceModel.Types;

namespace ServiceStack.Webhooks.UnitTests.ServiceModel
{
    public class SubscriptionDeliveryResultValidatorSpec
    {
        [TestFixture]
        public class GivenADto
        {
            private SubscriptionDeliveryResult dto;
            private SubscriptionDeliveryResultValidator validator;

            [SetUp]
            public void Initialize()
            {
                dto = new SubscriptionDeliveryResult
                {
                    Id = DataFormats.CreateEntityIdentifier(),
                    SubscriptionId = DataFormats.CreateEntityIdentifier()
                };
                validator = new SubscriptionDeliveryResultValidator();
            }

            [Test, Category("Unit")]
            public void WhenAllPropertiesValid_ThenSucceeds()
            {
                validator.ValidateAndThrow(dto);
            }

            [Test, Category("Unit")]
            public void WhenIdIsNull_ThenThrows()
            {
                dto.Id = null;

                validator.Validate(dto);

                Assert.That(() => validator.ValidateAndThrow(dto), Throws.TypeOf<ValidationException>().With.Message.Contain(Resources.SubscriptionDeliveryResultValidator_InvalidId));
            }

            [Test, Category("Unit")]
            public void WhenIdIsInvalid_ThenThrows()
            {
                dto.Id = "anid";

                validator.Validate(dto);

                Assert.That(() => validator.ValidateAndThrow(dto), Throws.TypeOf<ValidationException>().With.Message.Contain(Resources.SubscriptionDeliveryResultValidator_InvalidId));
            }

            [Test, Category("Unit")]
            public void WhenSubscriptionIdIsNull_ThenThrows()
            {
                dto.SubscriptionId = null;

                validator.Validate(dto);

                Assert.That(() => validator.ValidateAndThrow(dto), Throws.TypeOf<ValidationException>().With.Message.Contain(Resources.SubscriptionDeliveryResultValidator_InvalidSubscriptionId));
            }

            [Test, Category("Unit")]
            public void WhenSubscriptionIdIsInvalid_ThenThrows()
            {
                dto.SubscriptionId = "anid";

                validator.Validate(dto);

                Assert.That(() => validator.ValidateAndThrow(dto), Throws.TypeOf<ValidationException>().With.Message.Contain(Resources.SubscriptionDeliveryResultValidator_InvalidSubscriptionId));
            }
        }
    }
}

redpajama_set_name: RedPajamaGithub