#!/usr/bin/env perl

use strict;
use warnings;
use 5.020;

our $VERSION = '0.00';

use File::Slurp qw(read_file);
use Getopt::Long;
use Net::MQTT::Simple;
use Time::HiRes qw(usleep);

my $mqtt_host;

GetOptions(
	'h|host=s' => \$mqtt_host,
);

if ( not defined $mqtt_host or not length($mqtt_host) ) {
	die("Usage: $0 -h <hostname> [topic=value ...]\n");
}

my $mqtt   = Net::MQTT::Simple->new($mqtt_host);
my $retain = 0;

sub parse_content_string {
	my ($raw_content) = @_;
	if ( $raw_content =~ m{ ^ / [^/] }x ) {
		my $content = read_file( $raw_content, { err_mode => 'carp' } );
		if ( defined $content ) {
			chomp $content;
		}
		return $content;
	}
	# Allow //foo as escape for literal /foo messages
	$raw_content =~ s{ ^ / / }{/}x;
	return $raw_content;
}

for my $arg (@ARGV) {
	if ( $arg eq 'publish' ) {
		$retain = 0;
	}
	elsif ( $arg eq 'retain' ) {
		$retain = 1;
	}
	elsif ( $arg =~ m{ ^ (?<topic> [^=]+) = (?<content> .*) $ }x ) {
		my $content = parse_content_string( $+{content} );
		if ($retain) {
			$mqtt->retain( $+{topic}, $content );
		}
		else {
			$mqtt->publish( $+{topic}, $content );
		}
	}
}

# XXX Net::MQTT::Simple passes data to the socket layer, but does not wait for
# it to be successfully sent. So (especially on fast systems, e.g. modern
# Core i5/i7 CPUs) we might terminate before all data was transmitted, leading
# to loss of some messages.
#
# Fixing this probably requires a dive into Net::MQTT::Simple and possibly
# changes in its API, so let's dance the workaround dance for now.

usleep(100_000);

__END__

=head1 NAME

=head1 SYNOPSIS

=head1 VERSION

=head1 DESCRIPTION

=head1 OPTIONS

=over

=back

=head1 EXIT STATUS

=head1 CONFIGURATION

None.

=head1 DEPENDENCIES

=over

=back

=head1 BUGS AND LIMITATIONS

=head1 AUTHOR

Copyright (C) 2017 by Daniel Friesel E<lt>derf@finalrewind.orgE<gt>

=head1 LICENSE

  0. You just DO WHAT THE FUCK YOU WANT TO.