# BEGIN LICENSE BLOCK
# 
# Copyright (c) 1996-2003 Jesse Vincent <jesse@bestpractical.com>
# 
# (Except where explictly superceded by other copyright notices)
# 
# This work is made available to you under the terms of Version 2 of
# the GNU General Public License. A copy of that license should have
# been provided with this software, but in any event can be snarfed
# from www.gnu.org.
# 
# This work is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
# 
# Unless otherwise specified, all modifications, corrections or
# extensions to this work which alter its source code become the
# property of Best Practical Solutions, LLC when submitted for
# inclusion in the work.
# 
# 
# END LICENSE BLOCK
package RT::EmailParser;


use base qw/RT::Base/;

use strict;
use Mail::Address;
use MIME::Entity;
use MIME::Head;
use MIME::Parser;
use File::Temp qw/tempdir/;

=head1 NAME

  RT::EmailParser - helper functions for parsing parts from incoming
  email messages

=head1 SYNOPSIS


=head1 DESCRIPTION


=begin testing

ok(require RT::EmailParser);

=end testing


=head1 METHODS

=head2 new


=cut

sub new  {
  my $proto = shift;
  my $class = ref($proto) || $proto;
  my $self  = {};
  bless ($self, $class);
  return $self;
}



# {{{ sub debug

sub debug {
    my $val = shift;
    my ($debug);
    if ($val) {
        $RT::Logger->debug( $val . "\n" );
        if ($debug) {
            print STDERR "$val\n";
        }
    }
    if ($debug) {
        return (1);
    }
}

# }}}

# {{{ sub CheckForLoops 

sub CheckForLoops {
    my $self = shift;

    my $head = $self->Head;

    #If this instance of RT sent it our, we don't want to take it in
    my $RTLoop = $head->get("X-RT-Loop-Prevention") || "";
    chomp($RTLoop);    #remove that newline
    if ( $RTLoop =~ /^\Q$RT::rtname\E/o ) {
        return (1);
    }

    # TODO: We might not trap the case where RT instance A sends a mail
    # to RT instance B which sends a mail to ...
    return (undef);
}

# }}}

# {{{ sub CheckForSuspiciousSender

sub CheckForSuspiciousSender {
    my $self = shift;

    #if it's from a postmaster or mailer daemon, it's likely a bounce.

    #TODO: better algorithms needed here - there is no standards for
    #bounces, so it's very difficult to separate them from anything
    #else.  At the other hand, the Return-To address is only ment to be
    #used as an error channel, we might want to put up a separate
    #Return-To address which is treated differently.

    #TODO: search through the whole email and find the right Ticket ID.

    my ( $From, $junk ) = $self->ParseSenderAddressFromHead();

    if ( ( $From =~ /^mailer-daemon/i ) or ( $From =~ /^postmaster/i ) ) {
        return (1);

    }

    return (undef);

}

# }}}

# {{{ sub CheckForAutoGenerated
sub CheckForAutoGenerated {
    my $self = shift;
    my $head = $self->Head;

    my $Precedence = $head->get("Precedence") || "";
    if ( $Precedence =~ /^(bulk|junk)/i ) {
        return (1);
    }
    else {
        return (undef);
    }
}

# }}}

# {{{ sub ParseMIMEEntityFromSTDIN

sub ParseMIMEEntityFromSTDIN {
    my $self = shift;
    return $self->ParseMIMEEntityFromFileHandle(\*STDIN);
}

# }}}

=head2 ParseMIMEEntityFromScalar  $message

Takes either a scalar or a reference to a scalr which contains a stringified MIME message.
Parses it.

Returns true if it wins.
Returns false if it loses.


=cut

sub ParseMIMEEntityFromScalar {
    my $self = shift;
    my $message = shift;

    $self->_DoParse('parse_data', $message);

}

# {{{ ParseMIMEEntityFromFilehandle *FH

=head2 ParseMIMEEntityFromFilehandle *FH

Parses a mime entity from a filehandle passed in as an argument

=cut

sub ParseMIMEEntityFromFileHandle {
    my $self = shift;
    my $filehandle = shift;

    $self->_DoParse('parse', $filehandle);

}

# }}}

# {{{ ParseMIMEEntityFromFile

=head2 ParseMIMEEntityFromFile 

Parses a mime entity from a filename passed in as an argument

=cut

sub ParseMIMEEntityFromFile {
    my $self = shift;

    my $file = shift;
    $self->_DoParse('parse_open', $file);
}

# }}}

# {{{ _DoParse 

=head2 _DoParse PARSEMETHOD CONTENT


A helper for the various parsers to turn around and do the dispatch to the actual parser

=cut

sub _DoParse {
    my $self = shift;
    my $method = shift;
    my $file = shift;

    # Create a new parser object:

    my $parser = MIME::Parser->new();
    $self->_SetupMIMEParser($parser);


    # TODO: XXX 3.0 we really need to wrap this in an eval { }

    unless ( $self->{'entity'} = $parser->$method($file) ) {

        # Try again, this time without extracting nested messages
        $parser->extract_nested_messages(0);
        unless ( $self->{'entity'} = $parser->$method($file) ) {
            $RT::Logger->crit("couldn't parse MIME stream");
            return ( undef);
        }
    }
    $self->_PostProcessNewEntity();
    return (1);
}

# }}}


# {{{ _PostProcessNewEntity 

=head2 _PostProcessNewEntity

cleans up and postprocesses a newly parsed MIME Entity

=cut

sub _PostProcessNewEntity {
    my $self = shift;

    #Now we've got a parsed mime object. 

    # try to convert text parts into utf-8 charset
    RT::I18N::SetMIMEEntityToEncoding($self->{'entity'}, 'utf-8');


    # Unfold headers that are have embedded newlines
    $self->Head->unfold;


}

# }}}

# {{{ sub ParseTicketId 

sub ParseTicketId {
    my $self = shift;

    my $Subject = shift;

    if ( $Subject =~ s/\[\Q$RT::rtname\E\s+\#(\d+)\s*\]//i ) {
        my $id = $1;
        $RT::Logger->debug("Found a ticket ID. It's $id");
        return ($id);
    }
    else {
        return (undef);
    }
}

# }}}



# {{{ ParseCcAddressesFromHead 

=head2 ParseCcAddressesFromHead HASHREF

Takes a hashref object containing QueueObj, Head and CurrentUser objects.
Returns a list of all email addresses in the To and Cc 
headers b<except> the current Queue\'s email addresses, the CurrentUser\'s 
email address  and anything that the $RTAddressRegexp matches.

=cut

sub ParseCcAddressesFromHead {

    my $self = shift;

    my %args = (
        QueueObj    => undef,
        CurrentUser => undef,
        @_
    );

    my (@Addresses);

    # XXX: workaround for Outlook's habit of using ';' as separator; check with M::Address author
    my @ToObjs = Mail::Address->parse( join(',', split /;/, $self->Head->get('To')) );
    my @CcObjs = Mail::Address->parse( join(',', split /;/, $self->Head->get('Cc')) );

    foreach my $AddrObj ( @ToObjs, @CcObjs ) {
        my $Address = $AddrObj->address;
        my $user = RT::User->new($RT::SystemUser);
        $Address = $user->CanonicalizeEmailAddress($Address);
        next if ( $args{'CurrentUser'}->EmailAddress   =~ /^$Address$/i );
        next if ( $args{'QueueObj'}->CorrespondAddress =~ /^$Address$/i );
        next if ( $args{'QueueObj'}->CommentAddress    =~ /^$Address$/i );
        next if ( IsRTAddress($Address) );

        push ( @Addresses, $Address );
    }
    return (@Addresses);
}

# }}}

# {{{ ParseSenderAdddressFromHead

=head2 ParseSenderAddressFromHead

Takes a MIME::Header object. Returns a tuple: (user@host, friendly name) 
of the From (evaluated in order of Reply-To:, From:, Sender)

=cut

sub ParseSenderAddressFromHead {
    my $self = shift;

    #Figure out who's sending this message.
    my $From = $self->Head->get('Reply-To')
      || $self->Head->get('From')
      || $self->Head->get('Sender');
    return ( $self->ParseAddressFromHeader($From) );
}

# }}}

# {{{ ParseErrorsToAdddressFromHead

=head2 ParseErrorsToAddressFromHead

Takes a MIME::Header object. Return a single value : user@host
of the From (evaluated in order of Errors-To:,Reply-To:, From:, Sender)

=cut

sub ParseErrorsToAddressFromHead {
    my $self = shift;

    #Figure out who's sending this message.

    foreach my $header ( 'Errors-To', 'Reply-To', 'From', 'Sender' ) {

        # If there's a header of that name
        my $headerobj = $self->Head->get($header);
        if ($headerobj) {
            my ( $addr, $name ) = $self->ParseAddressFromHeader($headerobj);

            # If it's got actual useful content...
            return ($addr) if ($addr);
        }
    }
}

# }}}

# {{{ ParseAddressFromHeader

=head2 ParseAddressFromHeader ADDRESS

Takes an address from $self->Head->get('Line') and returns a tuple: user@host, friendly name

=cut

sub ParseAddressFromHeader {
    my $self = shift;
    my $Addr = shift;

    my @Addresses = Mail::Address->parse($Addr);

    my $AddrObj = $Addresses[0];

    unless ( ref($AddrObj) ) {
        return ( undef, undef );
    }

    my $Name = ( $AddrObj->phrase || $AddrObj->comment || $AddrObj->address );

    #Lets take the from and load a user object.
    my $Address = $AddrObj->address;

    return ( $Address, $Name );
}

# }}}

# {{{ IsRTAddress

=item IsRTaddress ADDRESS

Takes a single parameter, an email address. 
Returns true if that address matches the $RTAddressRegexp.  
Returns false, otherwise.

=begin testing

is(RT::EmailParser::IsRTAddress("","rt\@example.com"),1, "Regexp matched rt address" );
is(RT::EmailParser::IsRTAddress("","frt\@example.com"),undef, "Regexp didn't match non-rt address" );

=end testing

=cut

sub IsRTAddress {
    my $self = shift;
    my $address = shift;

    # Example: the following rule would tell RT not to Cc 
    #   "tickets@noc.example.com"
    if ( defined($RT::RTAddressRegexp) &&
                       $address =~ /$RT::RTAddressRegexp/ ) {
        return(1);
    } else {
        return (undef);
    }
}

# }}}


# {{{ CullRTAddresses

=item CullRTAddresses ARRAY

Takes a single argument, an array of email addresses.
Returns the same array with any IsRTAddress()es weeded out.

=begin testing

@before = ("rt\@example.com", "frt\@example.com");
@after = ("frt\@example.com");
ok(eq_array(RT::EmailParser::CullRTAddresses("",@before),@after), "CullRTAddresses only culls RT addresses");

=end testing

=cut

sub CullRTAddresses {
    my $self = shift;
    my @addresses= (@_);
    my @addrlist;

    foreach my $addr( @addresses ) {
      push (@addrlist, $addr)    unless IsRTAddress("", $addr);
    }
    return (@addrlist);
}

# }}}


# {{{ LookupExternalUserInfo


# LookupExternalUserInfo is a site-definable method for synchronizing
# incoming users with an external data source. 
#
# This routine takes a tuple of EmailAddress and FriendlyName
#   EmailAddress is the user's email address, ususally taken from
#       an email message's From: header.
#   FriendlyName is a freeform string, ususally taken from the "comment" 
#       portion of an email message's From: header.
#
# If you define an AutoRejectRequest template, RT will use this   
# template for the rejection message.


=item LookupExternalUserInfo

 LookupExternalUserInfo is a site-definable method for synchronizing
 incoming users with an external data source. 

 This routine takes a tuple of EmailAddress and FriendlyName
    EmailAddress is the user's email address, ususally taken from
        an email message's From: header.
    FriendlyName is a freeform string, ususally taken from the "comment" 
        portion of an email message's From: header.

 It returns (FoundInExternalDatabase, ParamHash);

   FoundInExternalDatabase must  be set to 1 before return if the user was
   found in the external database.

   ParamHash is a Perl parameter hash which can contain at least the following
   fields. These fields are used to populate RT's users database when the user 
   is created

    EmailAddress is the email address that RT should use for this user.  
    Name is the 'Name' attribute RT should use for this user. 
         'Name' is used for things like access control and user lookups.
    RealName is what RT should display as the user's name when displaying 
         'friendly' names

=cut

sub LookupExternalUserInfo {
  my $self = shift;
  my $EmailAddress = shift;
  my $RealName = shift;

  my $FoundInExternalDatabase = 1;
  my %params;

  #Name is the RT username you want to use for this user.
  $params{'Name'} = $EmailAddress;
  $params{'EmailAddress'} = $EmailAddress;
  $params{'RealName'} = $RealName;

  # See RT's contributed code for examples.
  # http://www.fsck.com/pub/rt/contrib/
  return ($FoundInExternalDatabase, %params);
}

# }}}

# {{{ Accessor methods for parsed email messages

=head2 Head

Return the parsed head from this message

=cut

sub Head {
    my $self = shift;
    return $self->Entity->head;
}

=head2 Entity 

Return the parsed Entity from this message

=cut

sub Entity {
    my $self = shift;
    return $self->{'entity'};
}

# }}}
# {{{ _SetupMIMEParser 

=head2 _SetupMIMEParser $parser

A private instance method which sets up a mime parser to do its job

=cut


    ## TODO: Does it make sense storing to disk at all?  After all, we
    ## need to put each msg as an in-core scalar before saving it to
    ## the database, don't we?

    ## At the same time, we should make sure that we nuke attachments 
    ## Over max size and return them

sub _SetupMIMEParser {
    my $self   = shift;
    my $parser = shift;

    # Set up output directory for files:

    my $tmpdir = File::Temp::tempdir( TMPDIR => 1, CLEANUP => 1 );
    push ( @{ $self->{'AttachmentDirs'} }, $tmpdir );
    $parser->output_dir($tmpdir);
    $parser->filer->ignore_filename(1);

    #If someone includes a message, extract it
    $parser->extract_nested_messages(1);

    $parser->extract_uuencode(1);    ### default is false

    # Set up the prefix for files with auto-generated names:
    $parser->output_prefix("part");

    # do _not_ store each msg as in-core scalar;

    $parser->output_to_core(0);
}

# }}}

sub DESTROY {
    my $self = shift;
    File::Path::rmtree([@{$self->{'AttachmentDirs'}}],0,1);
}



eval "require RT::EmailParser_Vendor";
die $@ if ($@ && $@ !~ qr{^Can't locate RT/EmailParser_Vendor.pm});
eval "require RT::EmailParser_Local";
die $@ if ($@ && $@ !~ qr{^Can't locate RT/EmailParser_Local.pm});

1;
