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(** This modules handles all the validation/application/finalisation
   of any operation related to the DAL. *)

open Alpha_context

(** [validate_attestation ctxt get_consensus_key op] checks whether the DAL
    attestation [op] is valid, assuming the delegate returned by
    [get_consensus_key ()] issued those attestations. If an [Error _] is
    returned, the [op] is not valid. *)
val validate_attestation :
  t ->
  (unit -> Consensus_key.pk tzresult Lwt.t) ->
  Dal.Attestation.operation ->
  Consensus_key.pk tzresult Lwt.t

(** [apply_attestation ctxt consensus_key op] applies [op.attestation] into the
   [ctxt] assuming [consensus_key.delegate] issued those attestations. *)
val apply_attestation :
  t -> Consensus_key.pk -> Dal.Attestation.operation -> t tzresult

(** [validate_publish_slot_header ctxt slot] ensures that [slot_header] is
   valid and prevents an operation containing [slot_header] to be
   refused on top of [ctxt]. If an [Error _] is returned, the [slot_header]
   is not valid. *)
val validate_publish_slot_header :
  t -> Dal.Operations.Publish_slot_header.t -> unit tzresult

(** [apply_publish_slot_header ctxt slot_header] applies the publication of
   slot header [slot_header] on top of [ctxt]. Fails if the slot contains
   already a slot header. *)
val apply_publish_slot_header :
  t -> Dal.Operations.Publish_slot_header.t -> (t * Dal.Slot.Header.t) tzresult

(** [finalisation ctxt] should be executed at block finalisation
   time. A set of slots attested at level [ctxt.current_level - lag]
   is returned encapsulated into the attestation data-structure.

   [lag] is a parametric constant specific to the data-availability
   layer.  *)
val finalisation : t -> (t * Dal.Attestation.t option) tzresult Lwt.t

(** [initialize ctxt ~level] should be executed at block
   initialisation time. It allows to cache the committee for [level]
   in memory so that every time we need to use this committee, there
   is no need to recompute it again. *)
val initialisation : t -> level:Level.t -> t tzresult Lwt.t

(** [compute_committee ctxt level] computes the DAL committee for [level]. *)
val compute_committee : t -> Level.t -> Dal.Attestation.committee tzresult Lwt.t