#!/usr/bin/perl

use strict;
use warnings;
use Getopt::Long;
use Mail::SRS qw(:all);

my ($secretfile, $alias, $forward, $reverse, $help);
my $separator = $SRSSEP;
my $hashlength = 4;
my @addresses;
my @secrets;
my $result = GetOptions (
				"separator=s"	=> \$separator,
				"address=s"		=> \@addresses,
				"secret=s"		=> \@secrets,
				"secretfile=s"	=> \$secretfile,
				"forward"		=> \$forward,
				"reverse"		=> \$reverse,
				"alias=s"		=> \$alias,
				"hashlength=i"	=> \$hashlength,
				"help"			=> \$help,
					);
if (!$result || $help) {
	print << "EOH";
Usage: srs [flags] [address ...]
   --separator=s      Specify the initial separator to be - + or =
   --address=s        Specify an address to transform
   --secret=s         Specify an SRS cryptographic secret
   --secretfile=s     Specify a file from which to read the secret
   --forward          Perform forward transformation
   --reverse          Perform reverse transformation
   --hashlength=i     Specify number of characters to use in the hash
   --help             Display this help
       =s denotes a string argument. =i denotes an integer argument
Multiple addresses are permitted. Multiple secrets are permitted.
EOH
	exit(1);
}

die "Separator character must be a single + - or =, not $separator"
				unless $separator =~ /^[=+-]$/;
die "Hash length _should_ be nonzero"
				unless $hashlength;

push(@addresses, @ARGV);
die "No address given!"
				unless @addresses;

if (defined $secretfile) {
	die "Secret file $secretfile not readable" unless -r $secretfile;
	local *FH;
	open(FH, "<$secretfile") or die "Cannot open $secretfile: $!";
	while (<FH>) {
		next unless /\S/;
		next if /^#/;
		push(@secrets, $_);
	}
	close(FH);
}

die "No secret or secretfile given. Use --secret or --secretfile, " .
				"and ensure the secret file is not empty."
					unless @secrets;

my $srs = new Mail::SRS(
				Secret		=> \@secrets,
				Separator	=> $separator,
				HashLength	=> $hashlength,
					);
my $newaddress;
if ($reverse) {
	print $srs->reverse($_), "\n" for @addresses;
}
else {
	die "I need an alias address or domain to do forwards transform. " .
					"Use --alias"
					unless defined $alias;
	print $srs->forward($_, $alias), "\n" for @addresses;
}

__END__

=head1 NAME

srs - command line interface to Mail::SRS

=head1 SYNOPSIS

srs --alias=alias@forwarder.com --secretfile=/etc/srs_secret \
		sender@source.com

=head1 DESCRIPTION

The srs commandline interface will create an instance of L<Mail::SRS>
with parameters derived from the commandline arguments and perform
forward or reverse transformations for all addresses given.

It is usually invoked from a sendmail envelope address
transformation rule, a qmail alias, or similar. See
http://www.anarres.org/projects/srs/ for examples.

Arguments take the form --name or --name=value.

=head1 ARGUMENTS

=head2 --separator

String, specified at most once. Defaults to $SRSSEP (C<=>).

Specify the initial separator for the SRS address. See L<Mail::SRS> for
details.

=head2 --address

String, may be specified multiple times, must be specified at least
once.

Specify a sender address to transform.

=head2 --secret

String, may be specified multiple times, at least one of --secret or
--secretfile must be specified.

Specify an SRS secret. The first specified secret is used for
encoding. All secrets are used for decoding.

=head2 --secretfile

String, specified at most once, at least one of --secret or
--secretfile must be specified.

A file to read for secrets. Secrets are specified once per line. The
first specified secret is used for encoding. Secrets are written
one per line. Blank lines and lines starting with a # are ignored.
If --secret is not given, then the secret file must be nonempty.

--secret will specify a primary secret and override --secretfile
if both are specified. However, secrets read from --secretfile will
still be used for decoding if both are specified.

=head2 --forward

No argument.

Specifies a forwards transformation. This is the default. --reverse
must not also be given.

=head2 --reverse

No argument.

Specifies a reverse transformation. --forward must not also be given.

=head2 --alias

String, must be specified exactly once if doing forwards transformation.

Provides the alias address to which the mail was sent. The domain-part
of this address is used in the generated SRS address. The local-part
and @ are optional and may be omitted.

=head2 --hashlength

Integer, may be specified at most once, defaults to 4.

Specify the number of base64 characters to use for the cryptographic
authentication code.

=head2 --help

Print some basic help.

=head1 SEE ALSO

L<Mail::SRS>, http://www.anarres.org/projects/srs/

=head1 AUTHOR

    Shevek
    CPAN ID: SHEVEK
    cpan@anarres.org
    http://www.anarres.org/projects/

=head1 COPYRIGHT

Copyright (c) 2004 Shevek. All rights reserved.

This program is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.

=cut