(*---------------------------------------------------------------------------
   Copyright (c) 2025 Thomas Gazagnaire. All rights reserved.
   SPDX-License-Identifier: ISC
  ---------------------------------------------------------------------------*)

(** DTN-native administrative records for borealis control.

    Instead of gRPC, borealis uses Bundle Protocol administrative records for
    control plane messages. This provides:
    - Single protocol for control and data
    - Store-and-forward tolerance
    - BPSec authentication
    - Compact CBOR encoding

    Admin bundles are sent to the node's admin endpoint ([ipn:NODE.0]). *)

(** {1 Admin Record Types} *)

type status = {
  node_id : Bundle.eid;
  uptime_secs : float;
  bundles_stored : int;
  bundles_forwarded : int;
  bundles_delivered : int;
  bundles_dropped : int;
  active_contacts : int;
}
(** Node status information. *)

type contact = {
  from_node : string;
  to_node : string;
  start_time : float;
  stop_time : float;
  rate_bps : float;
  owlt_secs : float;
}
(** A scheduled contact. *)

type contact_plan = { contacts : contact list }
(** A contact plan update. *)

type config_delta = {
  key : string;
  value : string option;  (** None means delete *)
}
(** Configuration change. *)

type query =
  | Query_status
  | Query_contacts
  | Query_policy
  | Query_bundles of { filter : string option }  (** Query types. *)

type response =
  | Response_status of status
  | Response_contacts of contact_plan
  | Response_policy of { source : string }
  | Response_bundles of { count : int; bundle_ids : string list }
  | Response_error of { code : int; message : string }  (** Query responses. *)

type t =
  | Status_report of status
  | Policy_update of { compiled : string; source : string }
  | Contact_update of contact_plan
  | Config_update of config_delta list
  | Query of query
  | Response of response  (** Administrative record types. *)

(** {1 CBOR Schema} *)

val codec : t Cbort.t
(** CBOR codec for admin records. *)

(** {1 Encoding/Decoding} *)

val encode : t -> string
(** [encode record] encodes to CBOR bytes. *)

val decode : string -> (t, string) result
(** [decode bytes] decodes from CBOR bytes. *)

(** {1 Bundle Creation} *)

val make_bundle :
  source:Bundle.eid ->
  destination:Bundle.eid ->
  timestamp:Bundle.timestamp ->
  t ->
  Bundle.t
(** [make_bundle ~source ~destination ~timestamp record] creates an admin bundle
    containing [record]. *)

val extract : Bundle.t -> (t, string) result
(** [extract bundle] extracts the admin record from an admin bundle. *)

val is_admin_bundle : Bundle.t -> bool
(** [is_admin_bundle bundle] returns true if this is an admin bundle. *)

(** {1 Utilities} *)

val pp : t Fmt.t
(** Pretty-printer. *)

val pp_status : status Fmt.t
val pp_contact : contact Fmt.t
val pp_query : query Fmt.t
val pp_response : response Fmt.t