package Sisimai::MTA::X5;
use parent 'Sisimai::MTA';
use feature ':5.10';
use strict;
use warnings;

my $Re0 = {
    'from' => qr/\bTWFpbCBEZWxpdmVyeSBTdWJzeXN0ZW0\b/,
    'to'   => qr/\bNotificationRecipients\b/,
};
my $Re1 = {
    'begin'    => qr|\AContent-Type: message/delivery-status|,
    'rfc822'   => qr|\AContent-Type: message/rfc822|,
    'endof'    => qr/\A__END_OF_EMAIL_MESSAGE__\z/,
};
my $Indicators = __PACKAGE__->INDICATORS;

sub description { 'Unknown MTA #5' }
sub smtpagent   { 'X5' }
sub pattern     { return $Re0 }

sub scan {
    # Detect an error from Unknown MTA #5
    # @param         [Hash] mhead       Message header of a bounce email
    # @options mhead [String] from      From header
    # @options mhead [String] date      Date header
    # @options mhead [String] subject   Subject header
    # @options mhead [Array]  received  Received headers
    # @options mhead [String] others    Other required headers
    # @param         [String] mbody     Message body of a bounce email
    # @return        [Hash, Undef]      Bounce data list and message/rfc822 part
    #                                   or Undef if it failed to parse or the
    #                                   arguments are missing
    # @since v4.13.0
    my $class = shift;
    my $mhead = shift // return undef;
    my $mbody = shift // return undef;
    my $match = 0;
    my $plain = '';

    # To: "NotificationRecipients" <...>
    $match++ if defined $mhead->{'to'} && $mhead->{'to'} =~ $Re0->{'to'};

    require Sisimai::MIME;
    if( $mhead->{'from'} =~ $Re0->{'from'} ) {
        # From: "=?iso-2022-jp?B?TWFpbCBEZWxpdmVyeSBTdWJzeXN0ZW0=?=" <...>
        #       Mail Delivery Subsystem
        for my $f ( split(' ', $mhead->{'from'}) ) {
            # Check each element of From: header
            next unless Sisimai::MIME->is_mimeencoded(\$f);
            $match++ if Sisimai::MIME->mimedecode([$f]) =~ m/Mail Delivery Subsystem/;
            last;
        }
    }

    if( Sisimai::MIME->is_mimeencoded(\$mhead->{'subject'}) ) {
        # Subject: =?iso-2022-jp?B?UmV0dXJuZWQgbWFpbDogVXNlciB1bmtub3du?=
        $plain = Sisimai::MIME->mimedecode([$mhead->{'subject'}]);
        $match++ if $plain =~ m/Mail Delivery Subsystem/;
    }
    return undef if $match < 2;

    my $dscontents = [__PACKAGE__->DELIVERYSTATUS];
    my @hasdivided = split("\n", $$mbody);
    my $rfc822part = '';    # (String) message/rfc822-headers part
    my $rfc822list = [];    # (Array) Each line in message/rfc822 part string
    my $blanklines = 0;     # (Integer) The number of blank lines
    my $readcursor = 0;     # (Integer) Points the current cursor position
    my $recipients = 0;     # (Integer) The number of 'Final-Recipient' header

    my $v = undef;
    my $p = '';

    for my $e ( @hasdivided ) {
        # Read each line between $Re1->{'begin'} and $Re1->{'rfc822'}.
        unless( $readcursor ) {
            # Beginning of the bounce message or delivery status part
            if( $e =~ $Re1->{'begin'} ) {
                $readcursor |= $Indicators->{'deliverystatus'};
                next;
            }
        }

        unless( $readcursor & $Indicators->{'message-rfc822'} ) {
            # Beginning of the original message part
            if( $e =~ $Re1->{'rfc822'} ) {
                $readcursor |= $Indicators->{'message-rfc822'};
                next;
            }
        }

        if( $readcursor & $Indicators->{'message-rfc822'} ) {
            # Before "message/rfc822"
            next unless length $e;
            $v = $dscontents->[-1];

            if( $e =~ m/\A[Ff]inal-[Rr]ecipient:[ ]*(?:RFC|rfc)822;[ ]*([^ ]+)\z/ ) {
                # Final-Recipient: RFC822; kijitora@example.jp
                if( length $v->{'recipient'} ) {
                    # There are multiple recipient addresses in the message body.
                    push @$dscontents, __PACKAGE__->DELIVERYSTATUS;
                    $v = $dscontents->[-1];
                }
                $v->{'recipient'} = $1;
                $recipients++;

            } elsif( $e =~ m/\A[Xx]-[Aa]ctual-[Rr]ecipient:[ ]*(?:RFC|rfc)822;[ ]*([^ ]+)\z/ ||
                     $e =~ m/\A[Oo]riginal-[Rr]ecipient:[ ]*(?:RFC|rfc)822;[ ]*([^ ]+)\z/ ) {
                # X-Actual-Recipient: RFC822; kijitora@example.co.jp
                # Original-Recipient: rfc822;kijitora@example.co.jp
                $v->{'alias'} = $1;

            } elsif( $e =~ m/\A[Aa]ction:[ ]*(.+)\z/ ) {
                # Action: failed
                $v->{'action'} = lc $1;

            } elsif( $e =~ m/\A[Ss]tatus:[ ]*(\d[.]\d+[.]\d+)/ ) {
                # Status: 5.1.1
                $v->{'status'} = $1;

            } elsif( $e =~ m/\A[Rr]eporting-MTA:[ ]*(?:DNS|dns);[ ]*(.+)\z/ ) {
                # Reporting-MTA: dns; mx.example.jp
                $v->{'lhost'} = lc $1;

            } elsif( $e =~ m/\A[Rr]emote-MTA:[ ]*(?:DNS|dns);[ ]*(.+)\z/ ) {
                # Remote-MTA: DNS; mx.example.jp
                $v->{'rhost'} = lc $1;

            } elsif( $e =~ m/\A[Ll]ast-[Aa]ttempt-[Dd]ate:[ ]*(.+)\z/ ) {
                # Last-Attempt-Date: Fri, 14 Feb 2014 12:30:08 -0500
                $v->{'date'} = $1;

            } else {
                # Get an error message from Diagnostic-Code: field
                if( $e =~ m/\A[Dd]iagnostic-[Cc]ode:[ ]*(.+?);[ ]*(.+)\z/ ) {
                    # Diagnostic-Code: SMTP; 550 5.1.1 <userunknown@example.jp>... User Unknown
                    $v->{'spec'} = uc $1;
                    $v->{'diagnosis'} = $2;

                } elsif( $p =~ m/\A[Dd]iagnostic-[Cc]ode:[ ]*/ && $e =~ m/\A[ \t]+(.+)\z/ ) {
                    # Continued line of the value of Diagnostic-Code header
                    $v->{'diagnosis'} .= ' '.$1;
                    $e = 'Diagnostic-Code: '.$e;
                }
            }
        } else {
            # After "message/rfc822"
            next unless $recipients;
            next unless $readcursor & $Indicators->{'deliverystatus'};

            unless( length $e ) {
                $blanklines++;
                last if $blanklines > 1;
                next;
            }
            push @$rfc822list, $e;
        }
    } continue {
        # Save the current line for the next loop
        $p = $e;
    }

    return undef unless $recipients;
    require Sisimai::String;

    for my $e ( @$dscontents ) {
        $e->{'diagnosis'} ||= Sisimai::String->sweep($e->{'diagnosis'});
        $e->{'agent'}       = __PACKAGE__->smtpagent;
    }

    $rfc822part = Sisimai::RFC5322->weedout($rfc822list);
    return { 'ds' => $dscontents, 'rfc822' => $$rfc822part };
}

1;
__END__

=encoding utf-8

=head1 NAME

Sisimai::MTA::X5 - bounce mail parser class for unknown MTA #5.

=head1 SYNOPSIS

    use Sisimai::MTA::X5;

=head1 DESCRIPTION

Sisimai::MTA::X5 parses a bounce email which created by Unknown MTA #5. Methods
in the module are called from only Sisimai::Message.

=head1 CLASS METHODS

=head2 C<B<description()>>

C<description()> returns description string of this module.

    print Sisimai::MTA::X5->description;

=head2 C<B<smtpagent()>>

C<smtpagent()> returns MTA name.

    print Sisimai::MTA::X5->smtpagent;

=head2 C<B<scan(I<header data>, I<reference to body string>)>>

C<scan()> method parses a bounced email and return results as a array reference.
See Sisimai::Message for more details.

=head1 AUTHOR

azumakuniyuki

=head1 COPYRIGHT

Copyright (C) 2015-2016 azumakuniyuki, All rights reserved.

=head1 LICENSE

This software is distributed under The BSD 2-Clause License.

=cut

