#!/usr/bin/perl
#
# REAN.pl - Retired Email Address Notifier
#
# Sends message from STDIO to all unread messages
# Preferably run this script as a cron job
#
# VERSION: 0.2, written May 2016, updated July 2020
# AUTHOR:  Philip K.
# EMAIL:   <philipk [at] posteo [dot] net>
# LICENSE: CC0

use strict;
use warnings;

# modules
use Net::IMAP::Simple;
use Email::Sender::Simple qw(sendmail);
use Email::MIME;

# Data setup
my ($imap_server,
    $imap_user,
    $imap_pass,
    $ignore_re) = @ARGV;

die "usage: ./rean.pl [server] [user] [password]"
  unless $imap_user and $imap_pass and $imap_server;
my $message = do { local $/; <STDIN> } or
  die "No message specified\n";

# IMAP setup
my $imap = Net::IMAP::Simple->new($imap_server) or
  die "Unable to connect to $imap_server: $Net::IMAP::Simple::errstr\n";
$imap->login($imap_user, $imap_pass) or
  die "IMAP login error: ${$imap->errstr}\n";

foreach my $i (1..$imap->select("INBOX")) {
  unless ($imap->seen($i)){
    my $mail = Email::Simple->new(join '', @{ $imap->top($i) });

    print "Noticed ${$mail->header(\"Subject\")}\n";
    if (($ignore_re =~ $mail->header("Subject")) ||
	($ignore_re =~ $mail->header("From"))) {
      continue ;
    }

    sendmail(Email::MIME->create
	     (header_str => [ From    => $mail->header("To"),
			      To      => $mail->header("From"),
			      Subject => ("Retired email-address notification"),
			      "X-Mailer" => "REAN v0.2" ],
	      attributes => { encoding => 'quoted-printable',
			      charset  => 'ISO-8859-1' },
	      body_str => $message));

    print "Replied to: ${$mail->header(\"To\")}\n";
  }
}