#!/usr/bin/perl

# Sample program for selecting filehandles.
# Copyright 2004 by Rocco Caputo.  Free software.
# Same terms as Perl itself.  Have fun!

use warnings;
use strict;

use IO::Socket::INET;
use POE;

POE::Session->create(
  inline_states => {
    _start    => \&handle_start,
    got_input => \&handle_input,
  },
);

POE::Kernel->run();
exit;

sub handle_start {
  my $udp_svr = IO::Socket::INET->new(
    Proto     => "udp",
    LocalPort => 8675,
  ) or die $!;

  $_[KERNEL]->select_read($udp_svr, "got_input");

  print(
    "This is a UDP service.\n",
    "Use `nc -u -w 1 localhost 8675` with it.\n"
  );
}

sub handle_input {
  my $socket = $_[ARG0];

  my $msg = "";
  my $remote = recv($socket, $msg, 4096, 0);

  unless (defined $remote) {
    warn "recv error: $!";
    $_[KERNEL]->select_read($socket);
    return;
  }

  $msg =~ tr[A-Za-z][N-ZA-Mn-za-m];

  send($socket, $msg, 0, $remote);
}