#!/usr/bin/perl -w
#
# this script modifies UNIX mailbox files exported from Forté Agent:
# it extracts the time from sent messages and creates a "Date:" header line
# set to this time
# - You will need Perl itself and the modules 'libnet' and 'MailTools'
#   (www.perl.com) and perhaps a basic understanding of Perl
# - The script assumes you are living in Western Europe (wrt Daylight
#   Savings Time/summer time). And it's not fully automated; for dates
#   in the last week of March and October, the script just puts
#   '+0&00' in the Date Header, you will have to decide yourself if it
#   has to be '+0100' or '+0200' (I was too lazy to program this out,
#   I was way faster to handle these cases myself).
# - It's kind of quick and dirty, it was written for a job that is done
#   only once ;-)
#
# Copyright (c) 1999 Peter Steiner <unistein@isbe.ch>


use Carp;
use Mail::Address;
use Mail::Internet;
use Net::SMTP;


#-------------------------------------------------------------------------------
sub processMail (\@)
{
    my @mail = @{shift()};
    my $mail = Mail::Internet->new(\@mail, Modify => 0, MailFrom => COERCE);

    # wenn das Mail keine Received:-Zeilen enthält, ist es ein gesendetes,
    # nicht ein empfangenes; wenn das Mail schon eine Zeit enthält, tun wir nichts
    if ( $mail->get('Received') || $mail->get('Date') )
    {
        # das Mail unverändert ausgeben (dh die From-Zeile wieder herstellen)
        my $from = $mail->get('Mail-From');
        $mail->delete('Mail-From');
        print join("", "From $from",@{$mail->header},"\n",@{$mail->body});
    }
    else
    {
        # wir nehmen für das Datum das aus der From-Zeile (als Mail-From gespeichert)
        # (From ???@??? DOW Month dd hh:mm:ss yyyy)
        my $from = $mail->get('Mail-From');
        $mail->delete('Mail-From');
        if ($from =~ /.*\@.* (Mon|Tue|Wed|Thu|Fri|Sat|Sun) (\w+) (\d+) (\d+:\d+:\d+) (\d+)/)
        {
            my ($dow,$month,$day,$time,$year) = ($1,$2,$3,$4,$5);

            # Ob jetzt zu einem bestimmten Datum Winter- oder Sommerzeit war,
            # bestimmen wir nur grob; Zweifelsfälle müssen manuell erledigt werden
            my $tz = "+0&00";   # default in Zweifelsfällen
            $tz = "+0100" if $month =~ /(Nov|Dec|Jan|Feb)/
                || ($day < 24 && $month eq "Mar");
            $tz = "+0200" if $month =~ /(Apr|May|Jun|Jul|Aug|Sep)/
                || ($day < 24 && $month eq "Oct");
            print join("",
                       "From $from",        # From-Zeile wieder herstellen
                       @{$mail->header},
                       "Date: $dow, $day $month $year $time $tz\n",
                       "\n",
                       @{$mail->body});
        }
    }
}


#-------------------------------------------------------------------------------

# ein Mailfile (RFC822/From-delimited) einlesen (STDIN oder erstes Argument)
# und es in einzelne Mails aufspalten
my @oneMail = ();
while (<>)
{
    if (/^From /)
    {
        processMail(@oneMail) if @oneMail;
        @oneMail = ();
        push @oneMail, $_;
    }
    else
    {
        push @oneMail, $_;
    }
}
# evtl. letztes Mail auch noch behandeln
processMail(@oneMail) if @oneMail;



exit 0;

# eof