defmodule DecentralisedBookIndex.Helpers do
  @moduledoc "Helpers for tests"

  @doc """
  Return a new map with same keys as in map_with_keys.
  """
  def get_submap(map, map_with_keys) when is_map(map_with_keys) do
    Map.take(map, Map.keys(map_with_keys))
  end

  def get_submap(map, keys) when is_list(keys) do
    Map.take(map, keys)
  end

  def get_submaps(map_list, keys) do
    Enum.map(map_list, fn map ->
      get_submap(map, keys)
    end)
  end

  def datetime_from_iso_8601(datetime_string) do
    case DateTime.from_iso8601(datetime_string) do
      {:ok, datetime, 0} -> datetime
      _ -> nil
    end
  end

  @doc """
  Return a new map with updated keys :inserted_at and :updated_at.
  Those keys will be transformed from string to DateTime.
  """
  def datetime_from_iso8601_for_map(map) do
    map
    |> Map.update(:inserted_at, nil, &datetime_from_iso_8601/1)
    |> Map.update(:updated_at, nil, &datetime_from_iso_8601/1)
  end

  def datetime_add_second_as_string(datetime, seconds) do
    datetime
    |> DateTime.add(seconds)
    |> DateTime.to_iso8601()
  end
end