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(** An [Answerer.t] is a set of callback functions, parameterized by
    [conn_info] record. The [conn_info] records contains values useful
    for the callback functions to perform their task, and known after
    the connection is set up.

    The callback functions are called when the node receives `P2p_messages.t`
    messages. The parameters are the values carried by the message, and
    a [request_info] record that contains values pertaining to the connection
    that may change during the life of the connection. *)

type 'msg conn_info = {
  peer_id : P2p_peer.Id.t;
  is_private : bool;
  write_advertise : P2p_point.Id.t list -> bool tzresult;
      (** [write_advertise points] must send the message [Advertise(points)]
          to the internal [peer_id]. It must return [Ok true] if the message
          has been successfully sent, [Ok false] if the message has been
          dropped, or fails with a corresponding error otherwise. *)
  write_swap_ack : P2p_point.Id.t -> P2p_peer.Id.t -> bool tzresult;
      (** [write_swap_ack (p1, p2)] must send the message [Swap_ack(p1, p2)]
          to the internal [peer_id]. It must return [Ok true] if the message
          has been successfully sent, [Ok false] if the message has been
          dropped, or fails with a corresponding error otherwise. *)
  messages : (int * 'msg) Lwt_pipe.Maybe_bounded.t;
}

type request_info = {
  last_sent_swap_request : (Time.System.t * P2p_peer.Id.t) option;
}

type 'msg callback = {
  bootstrap : request_info -> unit tzresult Lwt.t;
  advertise : request_info -> P2p_point.Id.t list -> unit Lwt.t;
  message : request_info -> int -> 'msg -> unit Lwt.t;
  swap_request : request_info -> P2p_point.Id.t -> P2p_peer.Id.t -> unit Lwt.t;
  swap_ack : request_info -> P2p_point.Id.t -> P2p_peer.Id.t -> unit Lwt.t;
}

type 'msg t = 'msg conn_info -> 'msg callback