(**************************************************************************)
(*                                                                        *)
(*    Copyright (c) 2014 - 2018.                                          *)
(*    Dynamic Ledger Solutions, Inc. <contact@tezos.com>                  *)
(*                                                                        *)
(*    All rights reserved. No warranty, explicit or implicit, provided.   *)
(*                                                                        *)
(**************************************************************************)

open Proto_alpha
open Alpha_context

type t = {
  predecessor: Block.t ;
  state: M.validation_state ;
  rev_operations: Operation.packed list ;
  header: Block_header.t ;
  delegate: Account.t ;
}
type incremental = t

let predecessor { predecessor ; _ } = predecessor

let level st = st.header.shell.level

let rpc_context st =
  let result = Alpha_context.finalize st.state.ctxt in
  {
    Alpha_environment.Updater.block_hash = Block_hash.zero ;
    block_header = { st.header.shell with fitness = result.fitness } ;
    context = result.context ;
  }

let rpc_ctxt =
  new Alpha_environment.proto_rpc_context_of_directory
    rpc_context Proto_alpha.rpc_services

let begin_construction ?(priority=0) ?timestamp (predecessor : Block.t) =
  Block.get_next_baker ~policy:(Block.By_priority priority)
    predecessor >>=? fun (delegate, priority, real_timestamp) ->
  Account.find delegate >>=? fun delegate ->
  let timestamp = Option.unopt ~default:real_timestamp timestamp in
  let contents = Block.Forge.contents ~priority () in
  let protocol_data = {
    Block_header.contents ;
    signature = Signature.zero ;
  } in
  let header = {
    Block_header.shell = {
      predecessor = predecessor.hash ;
      proto_level = predecessor.header.shell.proto_level ;
      validation_passes = predecessor.header.shell.validation_passes ;
      fitness = predecessor.header.shell.fitness ;
      timestamp ;
      (* TODO : CHECK THAT OUT -- incoherent level *)
      level = predecessor.header.shell.level ;
      context = Context_hash.zero ;
      operations_hash = Operation_list_list_hash.zero ;
    } ;
    protocol_data = {
      contents ;
      signature = Signature.zero ;
    } ;
  } in
  M.begin_construction
    ~predecessor_context: predecessor.context
    ~predecessor_timestamp: predecessor.header.shell.timestamp
    ~predecessor_fitness: predecessor.header.shell.fitness
    ~predecessor_level: predecessor.header.shell.level
    ~predecessor:predecessor.hash
    ~timestamp
    ~protocol_data
    () >>=? fun state ->
  return {
    predecessor ;
    state ;
    rev_operations = [] ;
    header ;
    delegate ;
  }

let add_operation st op =
  M.apply_operation st.state op >>=? fun (state, _result) ->
  return { st with state ; rev_operations = op :: st.rev_operations }

let finalize_block st =
  M.finalize_block st.state >>=? fun (result, _) ->
  let operations = List.rev st.rev_operations in
  let operations_hash =
    Operation_list_list_hash.compute [
      Operation_list_hash.compute (List.map Operation.hash_packed operations)
    ] in
  let header =
    { st.header with
      shell = {
        st.header.shell with
        operations_hash ; fitness = result.fitness ;
      } } in
  let hash = Block_header.hash header in
  return {
    Block.hash ;
    header ;
    operations ;
    context = result.context ;
  }