defmodule Matcha.Context.Table do
  @moduledoc """
  Functions and operators that `:table` match specs can use.

  The return values of specs created in this context do not differentiate
  between specs that fail to find a matching clause for the given input,
  and specs with matching clauses that literally return the `false` value;
  they return `{:returned, result}` tuples either way.
  """

  alias Matcha.Context

  use Context

  ###
  # CALLBACKS
  ##

  @impl Context
  def __erl_spec_type__ do
    :table
  end

  @impl Context
  def __default_match_target__ do
    {}
  end

  @impl Context
  def __valid_match_target__(match_target) do
    is_tuple(match_target)
  end

  @impl Context
  def __invalid_match_target_error_message__(match_target) do
    "test targets for `:table` specs must be a tuple, got: `#{inspect(match_target)}`"
  end

  @impl Context
  def __prepare_source__(source) do
    {:ok, source}
  end

  @impl Context
  def __emit_erl_test_result__(result) do
    {:emit, result}
  end

  @impl Context
  def __transform_erl_test_result__(result) do
    case result do
      {:ok, result, [], _warnings} -> {:ok, result}
      {:error, problems} -> {:error, problems}
    end
  end

  @impl Context
  def __transform_erl_run_results__(results) do
    {:ok, results}
  end
end