#!/usr/bin/env ruby

require 'eventmachine'
require 'socket'

module Flapper

  def receive_data data
    send_data ">>>you sent: #{data}"
    close_connection if data =~ /quit/i
  end

end

def local_ip
  # turn off reverse DNS resolution temporarily
  orig, Socket.do_not_reverse_lookup = Socket.do_not_reverse_lookup, true

  UDPSocket.open do |s|
    s.connect '64.233.187.99', 1
    s.addr.last
  end
ensure
  Socket.do_not_reverse_lookup = orig
end

start_every = 120
stop_after  = 60
bind_ip     = local_ip
bind_port   = 12345
EM.run {

  puts "#{Time.now}: starting server"
  server_init = EM.start_server bind_ip, bind_port, Flapper
  EM.add_timer(stop_after) do
    puts "#{Time.now}: stopping server"
    EM.stop_server(server_init)
  end

  EM.add_periodic_timer(start_every) do
    puts "#{Time.now}: starting server"
    server = EM.start_server bind_ip, bind_port, Flapper
    EM.add_timer(stop_after) do
      puts "#{Time.now}: stopping server"
      EM.stop_server(server)
    end
  end
}