defp get_free_name(list, name), do: get_free_name(list, name, 2, name)

defp get_free_name(list, name, num, base_name) do
  unless Enum.member?(list, name) do
    name
  else
    get_free_name(list, "#{base_name} #{num}", num + 1, base_name)
  end
end

def get_project_name(list_names, name), do: get_project_name(list_names, name, name, 2)
def get_project_name(list_names, name, generated_name, idx) do
  cond do
    name not in list_names -> name
    generated_name not in list_names -> generated_name
    true -> get_project_name(list_names, name, "#{name} #{idx}", idx + 1)
  end
end

defmodule Foo do
  defp construct_widget_name(widget, project) do
    project
    |> list_project_widgets_for_project()
    |> Stream.map(& &1.name)
    |> get_free_name(widget.name)
  end

  @spec get_free_name(
          project_widgets_enum :: Enumerable.t(),
          widget_base_name :: String.t(),
          widget_number_to_try :: non_neg_integer()
        ) :: first_awailable_name :: String.t()
  defp get_free_name(project_widgets_enum, widget_base_name, widget_number_to_try \\ 0) do
    name_on_current_iteration =
      case widget_number_to_try do
        0 -> "#{widget_name}"
        ordinal_number -> "#{widget_name} #{widget_number_to_try}"
      end

    case Enum.member?(project_widgets_enum, name_on_current_iteration) do
      true -> get_free_name(project_widgets_enum, widget_base_name, widget_number_to_try + 1)
      false -> name_on_current_iteration
    end
  end
end

project
    |> list_project_widgets_for_project()