-module(yaml_parser_utils).
-export([
    read_file/1,
    get_decorator/2,
    get_decorators/2,
    get_context/3,
    parse_args/2
]).

-include("../bt_node_behaviours/bt_nodes.hrl").


%% convert yaml file to dictionary
%% TODO: parse in detailed mode so better errors can be reported, which include line numbers
read_file(YAMLFilePath) ->
  [YAMLList] = yamerl_constr:file(YAMLFilePath),
  maps:from_list(YAMLList).

%% merge local bb keys with rest of context
%% local bb key => get_bb_key(local bb key)
get_context(Context, _Namespace, []) ->
  Context;
get_context(PartialContext, Namespace, [LocalBBKey | Rest]) ->
  NewPartialContext = maps:put(LocalBBKey, bt_blackboard:get_bb_key(Namespace, LocalBBKey), PartialContext),
  get_context(NewPartialContext, Namespace, Rest).

get_decorator(DecoratorList, Context) ->
  Module = proplists:get_value("module", DecoratorList),
  UnparsedArgs = proplists:get_value("args", DecoratorList),
  Name = proplists:get_value("name", DecoratorList, Module),
  % Params = proplists:get_value("params", DecoratorList, []),
  ModuleAtom = list_to_atom(Module),
  Params = ModuleAtom:get_params(),
  bt_parser_utils:throw_error_if_args_and_params_dont_match(Module, UnparsedArgs, Params),
  ArgsAsMap = parse_args(UnparsedArgs, Context),
  #decorator{
    name = Name,
    module = ModuleAtom,
    args = ArgsAsMap
  }.

get_decorators(undefined, _Context) ->
  [];
get_decorators(DecoratorsList, Context) ->
  [get_decorator(DecoratorList, Context) || DecoratorList <- DecoratorsList].


parse_args(Args, Context) ->
  parse_args(Args, #{}, Context).
parse_args([], NewContext, _Context) ->
  NewContext;
parse_args([{ArgKey, ArgVal} | Rest], NewContext, Context) ->
  %% check if arg val is in context; if so, then replace.
  ValToPut = parse_argval(ArgVal, Context),
  NewNewContext = maps:put(ArgKey, ValToPut, NewContext),
  parse_args(Rest, NewNewContext, Context).

parse_argval(ArgVal, Context) ->
  case maps:is_key(ArgVal, Context) of
    true -> maps:get(ArgVal, Context);
    false -> parse_argval_basic(ArgVal, Context)
  end.

%% can be deeply nested!
%% flawed logic because can't really detect if a list is string or not... but maybe don't need to?
parse_argval_basic(ArgVal, _Context) when is_atom(ArgVal); is_number(ArgVal); is_binary(ArgVal) ->
  ArgVal;
parse_argval_basic(ArgVal, Context) when is_tuple(ArgVal) ->
  %% split
  L = tuple_to_list(ArgVal),
  list_to_tuple(parse_argval_basic(L, Context));
parse_argval_basic(ArgVal, Context) when is_list(ArgVal) ->
  [parse_argval(X, Context) || X <- ArgVal].