#!/usr/bin/perl
use warnings;
use strict;

# $Id: lyris_filter,v 1.4 2003/10/11 06:16:15 pfeiffer Exp $

# lyris_filter - Kevin Pfeiffer <pfeiffer@iu-bremen.de>
# The LYRIS listserve software apparently breaks the In-Reply-To message 
# header, meaning that messages no longer thread properly.

# Piping messages managed by LYRIS listserve software through this filter
# will restore useable In-Reply-To and Message-ID headers for message threading

my $end_of_header = 0;

# while (<DATA>) {  # for testing
while (<>) {
    if ( $end_of_header == 0 ) {

            $_ =~ s/^Message-ID:\s+<LYRIS-\d+-\d+-(.*)--[^@]+@(.*)>/Message-ID: <$1-LYRIS\@$2>/i;
            $_ =~ s/^In-Reply-To:\s+<LYRIS-\d+-\d+-(.*)--[^@]+@(.*)>/In-Reply-To: <$1-LYRIS\@$2>/i;

            # in case on second line
            $_ =~ s/^\s+<LYRIS-\d+-\d+-(.*)--[^@]+@(.*)>/ <$1-LYRIS\@$2>/i;

            $end_of_header = 1 if /^$/;
    }
    print;
};

__END__
# THESE headers (in which the message IDs for _every_ list recipient are slightly different):
Message-ID: <LYRIS-1435126-434415-2003.10.02-12.48.58--pfeiffer#iu-bremen.de@listserver.somewhere.else>
In-Reply-To: <LYRIS-119451-434361-2003.10.02-12.10.54--karic#lclark.edu@listserver.itd.umich.edu>

# Are rewritten to:
# Message-ID: <2003.10.02-12.48.58-LYRIS@listserver.somewhere.else>
# In-Reply-To: <2003.10.02-12.10.54-LYRIS@listserver.itd.umich.edu>