-define(ALLOWED_CHANNELS, ["video", "audio", "text"]).
-define(ALLOWED_ROLES, ["admin", "user"]).


is_allowed_channels(Channels) when is_list(Channels) ->
  lists:subtract(Channels, ?ALLOWED_CHANNELS) == [].


fill_credentials(#credentials{} = Creds, []) -> Creds;

fill_credentials(#credentials{} = Creds, [{role, Role} | T]) ->
  case lists:member(Role, ?ALLOWED_ROLES) of
    true -> fill_credentials(Creds#credentials{role = Role}, T);
    _    -> fill_credentials(Creds, T)
  end;

fill_credentials(#credentials{} = Creds,
                 [{invisible, Invisible} | T]) ->
  case Invisible of
    Value when Value == true orelse Value == false  ->
      fill_credentials(Creds#credentials{invisible = Value}, T);
    _ ->
      fill_credentials(Creds, T)
  end;

fill_credentials(#credentials{} = Creds, [{record, Records} | T]) ->
  case is_allowed_channels(Records) of
    true -> fill_credentials(
              Creds#credentials{record = lists:sort(Records)}, T);
    _    -> fill_credentials(Creds, T)
  end;

fill_credentials(#credentials{} = Creds, [_H | T]) ->
  fill_credentials(Creds, T).