(*****************************************************************************)
(*                                                                           *)
(* Open Source License                                                       *)
(* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com>     *)
(*                                                                           *)
(* Permission is hereby granted, free of charge, to any person obtaining a   *)
(* copy of this software and associated documentation files (the "Software"),*)
(* to deal in the Software without restriction, including without limitation *)
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(* Software is furnished to do so, subject to the following conditions:      *)
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(* DEALINGS IN THE SOFTWARE.                                                 *)
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(*****************************************************************************)

(** Block header *)

type t = {shell : Block_header.shell_header; protocol_data : protocol_data}

and protocol_data = {contents : contents; signature : Signature.t}

and contents = {
  priority : int;
  seed_nonce_hash : Nonce_hash.t option;
  proof_of_work_nonce : MBytes.t;
}

type block_header = t

type raw = Block_header.t

type shell_header = Block_header.shell_header

let raw_encoding = Block_header.encoding

let shell_header_encoding = Block_header.shell_header_encoding

let contents_encoding =
  let open Data_encoding in
  def "block_header.alpha.unsigned_contents"
  @@ conv
       (fun {priority; seed_nonce_hash; proof_of_work_nonce} ->
         (priority, proof_of_work_nonce, seed_nonce_hash))
       (fun (priority, proof_of_work_nonce, seed_nonce_hash) ->
         {priority; seed_nonce_hash; proof_of_work_nonce})
       (obj3
          (req "priority" uint16)
          (req
             "proof_of_work_nonce"
             (Fixed.bytes Constants_repr.proof_of_work_nonce_size))
          (opt "seed_nonce_hash" Nonce_hash.encoding))

let protocol_data_encoding =
  let open Data_encoding in
  def "block_header.alpha.signed_contents"
  @@ conv
       (fun {contents; signature} -> (contents, signature))
       (fun (contents, signature) -> {contents; signature})
       (merge_objs
          contents_encoding
          (obj1 (req "signature" Signature.encoding)))

let raw {shell; protocol_data} =
  let protocol_data =
    Data_encoding.Binary.to_bytes_exn protocol_data_encoding protocol_data
  in
  {Block_header.shell; protocol_data}

let unsigned_encoding =
  let open Data_encoding in
  merge_objs Block_header.shell_header_encoding contents_encoding

let encoding =
  let open Data_encoding in
  def "block_header.alpha.full_header"
  @@ conv
       (fun {shell; protocol_data} -> (shell, protocol_data))
       (fun (shell, protocol_data) -> {shell; protocol_data})
       (merge_objs Block_header.shell_header_encoding protocol_data_encoding)

(** Constants *)

let max_header_length =
  let fake_shell =
    {
      Block_header.level = 0l;
      proto_level = 0;
      predecessor = Block_hash.zero;
      timestamp = Time.of_seconds 0L;
      validation_passes = 0;
      operations_hash = Operation_list_list_hash.zero;
      fitness = Fitness_repr.from_int64 0L;
      context = Context_hash.zero;
    }
  and fake_contents =
    {
      priority = 0;
      proof_of_work_nonce =
        MBytes.create Constants_repr.proof_of_work_nonce_size;
      seed_nonce_hash = Some Nonce_hash.zero;
    }
  in
  Data_encoding.Binary.length
    encoding
    {
      shell = fake_shell;
      protocol_data = {contents = fake_contents; signature = Signature.zero};
    }

(** Header parsing entry point  *)

let hash_raw = Block_header.hash

let hash {shell; protocol_data} =
  Block_header.hash
    {
      shell;
      protocol_data =
        Data_encoding.Binary.to_bytes_exn protocol_data_encoding protocol_data;
    }