#!/usr/bin/perl
# Copyright (c) 2003  Malte S. Stretz <spamassassin at msquadrat dot de>
#
# Modified by Duncan Findlay <duncf@debian.org>  May 2003
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of either the Artistic License or the GNU General
# Public License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.


use strict;
use bytes;

use vars qw {
  $opt_f $opt_h $opt_m $opt_H
};

use Getopt::Std;
getopts("f:hmH");

sub usage {
  die "extract-message-from-mbox [-f=file] [-m] [-H] offset

  Extracts the message starting at offset from file (or stdin). Very
  useful in combination with mass-check logs and mboxes. If the -m
  option is used, the input should be in \"mass-check\" format (as
  output by mass-check). Use the -H option to just output headers.
";
}

usage() if($opt_h || (!defined($ARGV[0]) && !$opt_m));
my $offset = $ARGV[0];

if($opt_m) {
  masscheck();
} else {
  $opt_f ||= '&STDIN';
  extract($opt_f, $offset);
}

sub extract {
  my $file = shift;
  my $offset = shift;
  my $found = 0;

  open (IN, "<$file");

  while(<IN>) {

    if(!$found) {
      $offset -= length;
      $found = $offset <= 0;
    } else {
      $found++ if(/^From /);
      last if($found == 3);
      print;
      last if ($opt_H && /^$/) # empty line? end of headers
    }
  }
}

sub masscheck {
  while (<STDIN>) {
    my $mail = (split(/\s+/, $_))[2];
    if ($mail =~ /^(.*)\.(\d+)$/) {
      extract($1, $2);
    } else { # could just be a filename. Lets print it anyway.
      chomp $mail;
      extract ($mail, 0);
    }
  }
}