#!/usr/bin/perl
use strict;
use warnings;

# based on net-mqtt-sub example from Net::MQTT
#
# 2020-08-15 Dobrica Pavlinusic <dpavlin@rot13.org>

use strict;
use Net::MQTT::Constants;
use Net::MQTT::Message;
use IO::Select;
use IO::Socket::INET;
use Time::HiRes;
use Getopt::Long;
use Pod::Usage;
use POSIX qw(strftime);
use File::Slurp;
use autodie;

use lib '.';
use Protocol;

my $queue = "queue";

$|=1; # flush STDOUT

my $help;
my $man;
my $verbose = 2;
my $host = 'localhost';
my $port = 1883;
my $count;
my $client_id;
my $keep_alive_timer = 120;
GetOptions('help|?' => \$help,
           'man' => \$man,
           'verbose+' => \$verbose,
           'host=s' => \$host,
           'port=i' => \$port,
           'count=i' => \$count,
           'one|1' => sub { $count = 1 },
           'client_id|client-id|C=s' => \$client_id,
           'keepalive=i' => \$keep_alive_timer) or pod2usage(2);
pod2usage(1) if ($help);
pod2usage(-exitstatus => 0, -verbose => 2) if $man;
#pod2usage(2) unless (@ARGV); # need a topic
push @ARGV, '#' unless (@ARGV);

open_again:
print "Open $host:port keep_alive_timer: $keep_alive_timer\n";
my $socket =
  IO::Socket::INET->new(PeerAddr => $host.':'.$port,
                        Timeout => $keep_alive_timer,
                       ) or die "Socket connect failed: $!\n";

my $buf = '';
my $mid = 1;
my $next_ping;
my $got_ping_response = 1;
my @connect = ( message_type => MQTT_CONNECT,
                keep_alive_timer => $keep_alive_timer );
push @connect, client_id => $client_id if (defined $client_id);
send_message($socket, @connect);
my $msg = read_message($socket, $buf) or die "No ConnAck\n";
print 'Received: ', $msg->string, "\n" if ($verbose >= 2);
send_message($socket, message_type => MQTT_SUBSCRIBE,
             message_id => $mid++,
             topics => [ map { [ $_ => MQTT_QOS_AT_MOST_ONCE ] } @ARGV ]);
$msg = read_message($socket, $buf) or die "No SubAck\n";
print 'Received: ', $msg->string, "\n" if ($verbose >= 2);

while (1) {
  $msg = read_message($socket, $buf);
  if ($msg) {
    my $t = time();
    print "\n",strftime("%Y-%m-%d %H:%M:%S ", localtime($t)) if $msg->message_type != MQTT_PINGRESP;
    if ($msg->message_type == MQTT_PUBLISH) {
      if ($verbose == 0) {
        print $msg->topic, " ", $msg->message, "\n";
      } else {
        print $msg->string, "\n";
      }

	my $topic = $msg->topic;
	my $dir = $topic;
	$dir =~ s{\w+/\w+/(\w+)/\w+}{$1};
	
	mkdir "$queue" if ( ! -e "$queue" );
	mkdir "$queue/$dir" if ( ! -e "$queue/$dir" );
	mkdir "$queue/$dir/up" if ( ! -e "$queue/$dir/up" );
	write_file "$queue/$dir/up/$t", $msg->string;

	mkdir "$queue/$dir/down" if ( ! -e "$queue/$dir/down" );
	mkdir "$queue/$dir/down/.done" if ( ! -e "$queue/$dir/down/.done" );

#	if ( $msg->topic =~ m{Inclinometer/ZCT330Ex_SWP_N_YK/869858031634109/up} ) {
	if ( substr($msg->message,2,1) eq "\x07" ) { # heartbeat
		$topic =~ s/up$/down/;

		my @all_pending = sort glob "$queue/$dir/down/*";
		if ( my $pending = shift @all_pending ) {
			my $raw = read_file $pending;

			send_message($socket,
				message_type => MQTT_PUBLISH,
				retain => 0, #$retain,
				topic => $topic,
				message => $raw);
			rename "$queue/$dir/down/$pending", "$queue/$dir/down/.done/$pending";
		}
      }

      if (defined $count && --$count == 0) {
        exit;
      }
    } elsif ($msg->message_type == MQTT_PINGRESP) {
      $got_ping_response = 1;
      print 'Received: ', $msg->string, "\n" if ($verbose >= 3);
    } else {
      print 'Received: ', $msg->string, "\n" if ($verbose >= 2);
    }
  }
  if (Time::HiRes::time > $next_ping) {
    die "Ping Response timeout.  Exiting\n" unless ($got_ping_response);
    send_message($socket, message_type => MQTT_PINGREQ);
  }
}

sub send_message {
  my $socket = shift;
  my $msg = Net::MQTT::Message->new(@_);
  print 'Sending: ', $msg->string, "\n" if ($verbose >= 2 && $_[1] eq 'message_type' && $_[2] != MQTT_PINGREQ);
  $msg = $msg->bytes;
  syswrite $socket, $msg, length $msg;
  print dump_string($msg, 'Sent: '), "\n\n" if ($verbose >= 3);
  $next_ping = Time::HiRes::time + $keep_alive_timer;
}

sub read_message {
  my $socket = shift;
  my $select = IO::Select->new($socket);
  my $timeout = $next_ping - Time::HiRes::time;
  do {
    my $mqtt = Net::MQTT::Message->new_from_bytes($_[0], 1);
    return $mqtt if (defined $mqtt);
    $select->can_read($timeout) || return;
    $timeout = $next_ping - Time::HiRes::time;
    my $bytes = sysread $socket, $_[0], 2048, length $_[0];
    unless ($bytes) {
      warn "Socket closed ", (defined $bytes ? 'gracefully' : 'error'), "\n";
      # FIXME reopen
      goto open_again;
    }
    print "Receive buffer: ", dump_string($_[0], '   '), "\n\n"
      if ($verbose >= 3);
  } while ($timeout > 0);
  return;
}

__END__

=pod

=encoding UTF-8

=head1 NAME

net-mqtt-sub - Perl script for subscribing to an MQTT topic

=head1 VERSION

version 1.143260

=head1 SYNOPSIS

  net-mqtt-sub [options] topic1 [topic2] [topic3] ...

=head1 DESCRIPTION

This script subscribes to one or more MQTT topics and prints any
messages that it receives to stdout.

=head1 OPTIONS

=over

=item B<-help>

Print a brief help message.

=item B<-man>

Print the manual page.

=item B<-host>

The host running the MQTT service.  The default is C<127.0.0.1>.

=item B<-port>

The port of the running MQTT service.  The default is 1883.

=item B<-client-id>

The client id to use in the connect message.  The default is
'NetMQTTpm' followed by the process id of the process.

=item B<-verbose>

Include more verbose output.  Without this option the script only
outputs errors and received messages one per line in the form:

  topic message

With one B<-verbose> options, publish messages are printed in a form
of a summary of the header fields and the payload in hex dump and text
form.

With two B<-verbose> options, summaries are printed for all messages
sent and received.

With three B<-verbose> options, a hex dump of all data transmitted and
received is printed.

=item B<-keepalive NNN>

The keep alive timer value.  Defaults to 120 seconds.  For simplicity,
it is also currently used as the connection/subscription timeout.

=item B<-count NNN>

Read the specificed number of MQTT messages and then exit.  Default
is 0 - read forever.

=item B<-one> or B<-1>

Short for B<-count 1>.  Read one message and exit.

=back

=head1 SEE ALSO

Net::MQTT::Message(3)

=head1 DISCLAIMER

This is B<not> official IBM code.  I work for IBM but I'm writing this
in my spare time (with permission) for fun.

=head1 AUTHOR

Mark Hindess <soft-cpan@temporalanomaly.com>

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2014 by Mark Hindess.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=cut