defmodule FlowAssertions.Checkers do
  alias FlowAssertions.Define.Defchecker.Failure
  import FlowAssertions.Define.Defchecker
  alias FlowAssertions.Messages

  @moduledoc """
  Functions that create handy predicates for use with `FlowAssertions.MiscA.assert_good_enough/2`


      actual
      |> assert_good_enough( in_any_order([1, 2, 3]))

  "Checkers" typically provide custom failure messages that are better than
  what a simple predicate would provide.

  This module is a work in progress.
  """

  @doc """
  Check equality of Enumerables, ignoring order.

      actual
      |> assert_good_enough( in_any_order([1, 2, 3]))

  In case of error, the actual and expected enumerables are sorted by
  by their `Kernel.inspect/1` representation. In combination with ExUnit's
  color-coded differences, that makes it easier to see what went wrong.
  
  """

  def in_any_order(expected) do
    fn actual ->
      assert = fn value, message ->
        if !value do
          Failure.boa(actual, :in_any_order, expected)
          |> fail_helpfully(message, alphabetical_enums(actual, expected))
        end
      end

      id = fn x -> x end
      unordered = &(Enum.group_by(&1, id))

      assert.(length(actual) == length(expected),
        Messages.different_length_collections)

      assert.(unordered.(actual) == unordered.(expected),
        Messages.different_elements_collections)
      true
    end
  end

  defp alphabetical_enums(actual, expected),
    do: [left: alphabetical(actual), right: alphabetical(expected)]
  defp alphabetical(xs), do: Enum.sort_by(xs, &to_string/1)

    

  @doc """
  TBD
  """
  def contains(expected) when is_binary(expected) do
    fn actual ->
      if String.contains?(actual, expected),
        do: true,
        else: Failure.boa(actual, :contains, expected)
    end
  end

  # m = quote do 
  #   defchecker contains2(expected) do
  #     fn actual -> String.contains?(actual, expected) end
  #   end
  # end

  # IO.puts Macro.expand_once(m, __ENV__) |> Macro.to_string


    # defchecker contains2(expected) do
    #   fn actual -> String.contains?(actual, expected) end
    # end
  
end