def check_again_soon(response, id)
  EM.add_timer(0.5) do
    if $peers.length < 2
      $log.debug "Still not enough peers, rescheduling check again..."
      check_again_soon(response, id)
    else
      $log.debug "Deleting self from collection..."
      $peers.delete(id)
      respond_with_random_peer(response, id)
    end
  end
end

def respond_with_random_peer(response, id)
  $log.debug "Responding with peer..."
  peer = $peers.keys.first
  $peers[peer] = id
  response << peer
  response.done
end

app = proc do |env|
  id = Rack::Request.new(env).POST['id']
  #return [ 404, {}, [] ] if id.nil?
  id = "1a2a3a4a" if id.nil?

  response = Thin::AsyncResponse.new(env)
  response.status = 200
  unless $peers.empty?
    $log.debug "Peers collection not empty"
    respond_with_random_peer(response, id)
  else
    $log.debug "Peers collection is empty, adding self to collection and scheduling another check soon..."
    $peers[id] = nil

    check_again_soon(response, id)
  end
  response.finish
end

run app