#!/usr/bin/perl

# http://perlmonks.org/?node_id=1181364

use strict;
use warnings;
use IO::Socket;
use IO::Select;

my $listenport;
my $othersocket;
my $otherport;
my $sendinterval;

my $pc1 = @ARGV && $ARGV[0] eq 'pc1';

if( $pc1 )
  {
  $listenport = 8010;
  $sendinterval = 5;
  $otherport = 'localhost:8000';
  }
else
  {
  $listenport = 8000;
  $sendinterval = 7;
  $otherport = 'localhost:8010';
  }

my $ls = IO::Socket::INET->new(
  Listen => 10, LocalPort => $listenport, Reuse => 1,
  ) or die "$@ opening listen socket on port $listenport";
warn "listening on $listenport\n";

my $sel = IO::Select->new($ls);

my $nextsend = $sendinterval + time;

while(1)
  {
  my $delta = $nextsend - time;
  if( $delta <= 0 )
    {
    if( not defined $othersocket)
      {
      if( $othersocket = IO::Socket::INET->new($otherport) )
        {
        warn "opened client at $otherport\n";
        $sel->add( $othersocket );
        }
      else
        {
        warn "open failed $@\n";
        }
      }
    if( $othersocket )
      {
      my $msg = $pc1 ? "ADD\n" : "STAT\n";
      print $othersocket $msg;
      print "sent $msg";
      }
    $nextsend = $sendinterval + time;
    }
  else
    {
    for my $h ($sel->can_read($delta))
      {
      if($h == $ls)
        {
        $sel->add(my $new = $h->accept);
        }
      elsif(sysread $h, my $in, 1024)
        {
        if( $othersocket and $h == $othersocket )
          {
          print "should be ack: $in";
          }
        else
          {
          print "got $in";
          print $h "ack to $in";
          }
        }
      else
        {
        $othersocket and $h == $othersocket and $othersocket = undef;
        $sel->remove($h);
        close $h;
        print "closed.\n";
        }
      }
    }
  }

__END__