-module(erl_parse_sequence).
-include("bt_nodes.hrl").
-export([
  parse/3
]).

get_child_and_blackboard({Child, Idx}, Namespace, BB) ->
  IdxString = integer_to_list(Idx),
  ChildNamespace = bt_parser_utils:get_namespace(Namespace, IdxString),
  bt_erl_parser:parse(Child, ChildNamespace, BB).


-spec parse(Node :: bt_node(), Namespace :: namespace(), BB :: blackboard()) -> {Node :: bt_node(), NewBB :: blackboard()}.
parse(Sequence = #sequence{children = Children}, Namespace, BB) when is_record(Sequence, sequence) ->
  %% parse the children with their own namespaces.
  ChildrenBBPairs = [
    get_child_and_blackboard(X, Namespace, BB) 
    || X <- lists:zip(Children, lists:seq(1, length(Children)))],
  %% merge all the blackboards
  NewBB = lists:foldl(
    fun({_ChildTree, ChildBB}, Acc) -> maps:merge(ChildBB, Acc) end,
    BB,
    ChildrenBBPairs
  ),
  ChildrenTrees = [X || {X, _} <- ChildrenBBPairs],
  {Sequence#sequence{children = ChildrenTrees, namespace = Namespace}, NewBB}.