Upnpsd stuff

defmodule Upnpsd do
  @inaddr_mcast {239,255,255,250}
  @ttl 4
  @port 1900

  defp setup_socket() do
    options = [{:reuseaddr, true}, {:as, :list}]
    Socket.UDP.open!(1900, options)
  end

  defp create_discovery_payload(service_type) do
"M-SEARCH * HTTP/1.1\r
HOST: 239.255.255.250:1900\r
MAN: \"ssdp:discover\"\r
ST: #{service_type}\r
MX: 3\r\n\r
"
  end

  def discover(service_type) do
    # Use a 3 second timeout, if it takes longer,
    # its likely NOT on the lan.
    recv_options = [{:timeout,3000}]

    # Header style payload for packet
    payload = create_discovery_payload service_type
    server = setup_socket

    :ok = Socket.Datagram.send!(server, payload, {@inaddr_mcast, @port})
    {data, _} = Socket.Datagram.recv! server, recv_options
    Socket.close server
    to_string data
  end


end

defmodule Upnpsd do
  @inaddr_mcast {239,255,255,250}
  @ttl 4
  @port 1900
  @timeout 3000


  def discover(service_type) do
    # Header style payload for packet
    service_type
    |> create_discovery_payload 
    |> send_datagram(setup_socket)
    |> to_string
  end

  defp send_datagram(payload, server) do
    :ok = Socket.Datagram.send!(server, payload, {@inaddr_mcast, @port})
    {data, _} = Socket.Datagram.recv!(server, timeout: @timeout)
    Socket.close(server)

    data
  end

  defp setup_socket() do
    Socket.UDP.open!(1900, reuseaddr: true, as: :list)
  end

  defp create_discovery_payload(service_type) do
    """
    M-SEARCH * HTTP/1.1\r
    HOST: 239.255.255.250:1900\r
    MAN: \"ssdp:discover\"\r
    ST: #{service_type}\r
    MX: 3\r\n\r
    """
  end

end