open Swim.Types

external env_cast : 'a -> 'b = "%identity"

let hex_of_cstruct cs =
  let len = Cstruct.length cs in
  let buf = Buffer.create (len * 2) in
  for i = 0 to len - 1 do
    Buffer.add_string buf (Printf.sprintf "%02x" (Cstruct.get_uint8 cs i))
  done;
  Buffer.contents buf

let () =
  Eio_main.run @@ fun env ->
  let env = env_cast env in
  Eio.Switch.run @@ fun sw ->
  let net = env#net in
  let sock =
    Swim.Transport.create_udp_socket net ~sw ~addr:"\127\000\000\001" ~port:7947
  in

  Printf.printf "Listening on 127.0.0.1:7947 for UDP packets...\n%!";

  let buf = Cstruct.create 1500 in
  for i = 1 to 10 do
    Printf.printf "Waiting for packet %d...\n%!" i;
    let src, n = Eio.Net.recv sock buf in
    let received = Cstruct.sub buf 0 n in
    Printf.printf "Received %d bytes from %s\n%!" n
      (match src with
      | `Udp (ip, port) ->
          Printf.sprintf "%s:%d" (Fmt.to_to_string Eio.Net.Ipaddr.pp ip) port
      | _ -> "unknown");
    Printf.printf "Hex: %s\n%!" (hex_of_cstruct received);
    Printf.printf "First byte (msg type): %d\n%!" (Cstruct.get_uint8 received 0);

    (* Try to decode *)
    match Swim.Codec.decode_packet received with
    | Ok packet -> Printf.printf "Decoded! Cluster: %s\n%!" packet.cluster
    | Error e -> Printf.printf "Decode error: %s\n%!" (decode_error_to_string e)
  done