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(** Tezos Shell - Prevalidation of pending operations (a.k.a Mempool) *)

(** The prevalidator is in charge of the "mempool" (a.k.a. the
    set of known not-invalid-for-sure operations that are not yet
    included in the blockchain).

    The prevalidator also maintains a sorted subset of the mempool that
    might correspond to a valid block on top of the current head. The
    "in-progress" context produced by the application of those
    operations is called the (pre)validation context.

    Before including an operation into the mempool, the prevalidation
    worker tries to append the operation the prevalidation context. If
    the operation is (strongly) refused, it will not be added into the
    mempool and then it will be ignored by the node and never
    broadcast. If the operation is only "branch_refused" or
    "branch_delayed", the operation won't be appended in the
    prevalidation context, but still broadcast.

*)

(** An (abstract) prevalidator context. Separate prevalidator contexts should be
 * used for separate chains (e.g., mainchain vs testchain). *)
type t

(** This record contains the differents limits and settings that can be updated
    from a node configuration for a prevalidator *)
type limits = {
  max_refused_operations : int;
      (** The maximum number of operations tracked by the mempool for each of
          the [refused], [branch delayed], [branch refused] and [outdated]
          operation classifications. Default is [1000] *)
  operation_timeout : Time.System.Span.t;
      (** The maximum time allowed to fetch the contents of an operation
          advertised by a remote peer. Default is [10] seconds *)
  operations_batch_size : int;
      (** Maximum number of pending operations processed (or classified) at the
          end of each request to the prevalidator worker. Default is [50] *)
  disable_precheck : bool;
      (** If [disable_precheck] is [true] (default is [false]) operations are
          executed by the protocol before being propagated. This flag is
          intended to be used for testing and debugging. *)
}

(** Sane default values for {!limits} *)
val default_limits : limits

(** Creates/tear-down a new prevalidator context. *)
val create :
  limits ->
  (module Prevalidator_filters.FILTER) ->
  Distributed_db.chain_db ->
  t tzresult Lwt.t

val shutdown : t -> unit Lwt.t

(** Notify the prevalidator that the identified peer has sent a bunch of
 * operations relevant to the specified context. *)
val notify_operations : t -> P2p_peer.Id.t -> Mempool.t -> unit Lwt.t

(** [inject_operation t ~force op] notifies the prevalidator worker of a new
    injected operation. If [force] is set to [true] the operation is injected
    without any check. [force] should be used for test purpose only. *)
val inject_operation : t -> force:bool -> Operation.t -> unit tzresult Lwt.t

(** Notify the prevalidator that a new head has been selected.
    [update] is used as an optimisation to know which operations
    previously classified require to be prevalidated again. *)
val flush :
  t ->
  Chain_validator_worker_state.Event.update ->
  Block_hash.t ->
  Block_hash.Set.t ->
  Operation_hash.Set.t ->
  unit tzresult Lwt.t

(** Returns the list of prevalidation contexts running and their associated chain *)
val running_workers : unit -> (Chain_id.t * Protocol_hash.t * t) list

(** Worker status and events *)

(* None indicates the there are no workers for the current protocol. *)
val status : t -> Worker_types.worker_status

val pending_requests :
  t -> (Time.System.t * Prevalidator_worker_state.Request.view) list

val current_request :
  t ->
  (Time.System.t * Time.System.t * Prevalidator_worker_state.Request.view)
  option

val information : t -> Worker_types.worker_information

val pipeline_length : t -> int

val rpc_directory : t option RPC_directory.t

(**/**)

module Internal_for_tests : sig
  (** Documented in {!Prevalidator}, because this is only exported for tests. *)
  type 'prevalidation_t tools = {
    advertise_current_head : mempool:Mempool.t -> Store.Block.t -> unit;
    chain_tools : Store.Block.t Prevalidator_classification.chain_tools;
    create :
      predecessor:Store.Block.t ->
      live_operations:Operation_hash.Set.t ->
      timestamp:Time.Protocol.t ->
      unit ->
      'prevalidation_t tzresult Lwt.t;
    fetch :
      ?peer:P2p_peer.Id.t ->
      ?timeout:Time.System.Span.t ->
      Operation_hash.t ->
      Operation.t tzresult Lwt.t;
    read_block : Block_hash.t -> Store.Block.t tzresult Lwt.t;
    send_get_current_head : ?peer:P2p_peer_id.t -> unit -> unit;
    set_mempool : head:Block_hash.t -> Mempool.t -> unit tzresult Lwt.t;
  }

  (** Documented in {!Prevalidator}, because this is only exported for tests. *)
  type worker_tools = {
    push_request : unit Prevalidator_worker_state.Request.t -> unit Lwt.t;
    push_request_now : unit Prevalidator_worker_state.Request.t -> unit;
  }

  (** The corresponding internal type of the mempool (see {!Prevalidator.S}),
      that is independent from the protocol. *)
  type ('a, 'b) types_state_shell

  (** Create a pristine value of {!type_state_shell} *)
  val mk_types_state_shell :
    predecessor:Store.Block.t ->
    tools:'prevalidation_t tools ->
    worker:worker_tools ->
    ('protocol_data, 'prevalidation_t) types_state_shell

  module Make
      (Filter : Prevalidator_filters.FILTER)
      (Prevalidation_t : Prevalidation.T
                           with type validation_state =
                                 Filter.Proto.validation_state
                            and type protocol_operation = Filter.Proto.operation
                            and type operation_receipt =
                                 Filter.Proto.operation_receipt) : sig
    (** The corresponding internal type of the mempool (see {!Prevalidator.S}),
        that depends on the protocol *)
    type types_state

    (** Create a pristine value of {!type_state} *)
    val mk_types_state :
      shell:
        ( Prevalidation_t.protocol_operation,
          Prevalidation_t.t )
        types_state_shell ->
      validation_state:Prevalidation_t.t ->
      types_state Lwt.t

    (** [to_shell pv] returns the shell part of [pv] *)
    val to_shell :
      types_state ->
      (Prevalidation_t.protocol_operation, Prevalidation_t.t) types_state_shell

    (** Documented in {!Prevalidator.S} *)
    val handle_unprocessed : types_state -> unit Lwt.t

    (** Documented in {!Prevalidator.S} (as are all the functions of this module) *)
    module Requests : sig
      val on_advertise : _ types_state_shell -> unit

      val on_arrived :
        types_state -> Operation_hash.t -> Operation.t -> unit tzresult Lwt.t

      val on_ban : types_state -> Operation_hash.t -> unit tzresult Lwt.t

      val on_flush :
        handle_branch_refused:bool ->
        types_state ->
        Store.Block.t ->
        Block_hash.Set.t ->
        Operation_hash.Set.t ->
        unit tzresult Lwt.t

      val on_inject :
        types_state -> force:bool -> Operation.t -> unit tzresult Lwt.t

      val on_notify :
        _ types_state_shell -> P2p_peer_id.t -> Mempool.t -> unit Lwt.t
    end
  end
end