(*****************************************************************************)
(*                                                                           *)
(* Open Source License                                                       *)
(* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com>     *)
(* Copyright (c) 2019 Nomadic Labs, <contact@nomadic-labs.com>               *)
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type t = {
  chain_name : Distributed_db_version.Name.t;
  distributed_db_version : Distributed_db_version.t;
  p2p_version : P2p_version.t;
}

val pp : Format.formatter -> t -> unit

val encoding : t Data_encoding.t

(** Get the network protocol version to announce on peer connection.

    Use the highest [distributed_db_versions] and the highest [p2p_versions].
    The version also contains the [chain_name] since it is used to prevent
    peers from different networks to communicate.

    Neither [distributed_db_versions] nor [p2p_versions] can be empty. *)
val announced :
  chain_name:Distributed_db_version.Name.t ->
  distributed_db_versions:Distributed_db_version.t list ->
  p2p_versions:P2p_version.t list ->
  t

(** Try to find a version which is supported both by us and a peer.

    Usage: [select ~chain_name ~distributed_db_versions ~p2p_versions remote_version]

    If the chain name of [remote_version] is not equal to [chain_name],
    there is no compatible version.

    [distributed_db_versions] is the list of distributed database versions
    supported by the node.
    If the highest supported version is lesser or equal to the remote version,
    use this highest supported version.
    Otherwise, there is no compatible version.

    Similarly, [p2p_versions] is the list of peer-to-peer versions
    supported by the node. The rules to find a compatible version are the same
    as the ones for [distributed_db_versions].

    If there is no compatible version, return a [P2p_rejection.Rejecting] error. *)
val select :
  chain_name:Distributed_db_version.Name.t ->
  distributed_db_versions:Distributed_db_version.t list ->
  p2p_versions:P2p_version.t list ->
  t ->
  t Error_monad.tzresult

(**/**)

module Internal_for_tests : sig
  val mock : unit -> t
end