defmodule Vela.Macros do
  @moduledoc false

  alias Vela.Stubs

  defmacro use_config(opts) do
    quote do
      Enum.map(unquote(opts), fn {serie, vela} ->
        vela =
          vela
          |> Keyword.put_new(:sorter, &Stubs.sort/2)
          |> Keyword.put_new(:compare_by, &Stubs.itself/1)
          |> Keyword.put_new(:comparator, &Stubs.compare/2)
          |> Keyword.put_new(:corrector, &Stubs.correct/3)
          |> Keyword.put_new(:threshold, nil)
          |> Keyword.update(:validator, &Stubs.validate/1, fn existing ->
            case existing do
              fun when is_function(fun, 1) or is_function(fun, 2) -> fun
              m when is_atom(m) -> &m.valid?/2
              other -> raise Vela.AccessError, field: :validator
            end
          end)

        {serie, vela}
      end)
    end
  end

  def use_types(extra_types) when is_list(extra_types) do
    extra_types =
      Enum.map(extra_types, fn
        {k, nil} ->
          {k, [{{:., [], [{:__aliases__, [alias: false], [:Vela]}, :value]}, [], []}]}

        {k, type} when is_atom(type) ->
          {k, {type, [], []}}

        {k, {{_, _, _} = module, type}} ->
          {k, {{:., [], [module, type]}, [], []}}

        {k, {module, type}} when is_atom(module) and is_atom(type) ->
          modules = module |> Module.split() |> Enum.map(&:"#{&1}")
          {k, {{:., [], [{:__aliases__, [alias: false], modules}, type]}, [], []}}

        {k, v} ->
          {k, v}
      end)

    {:%{}, [],
     [
       {:__struct__, {:__MODULE__, [], Elixir}},
       {:__errors__,
        [
          {{:., [], [{:__aliases__, [alias: false], [:Vela]}, :kv]}, [], []}
        ]},
       {:__meta__, {:keyword, [], []}}
       | extra_types
     ]}
  end

  defmacro main_ast do
    quote do
      @doc "Returns the list of series declared on #{__MODULE__}"
      @spec series :: [Vela.serie()]
      def series, do: @fields_ordered

      @doc "Returns the config #{__MODULE__} was declared with"
      @spec config :: [{atom(), Vela.options()}]
      def config, do: @config

      @doc "Returns the config for the serie `serie`, #{__MODULE__} was declared with"
      @spec config(Vela.serie()) :: Vela.options()
      def config(serie), do: @config[serie]

      @doc "Returns the config value for the serie `serie`, #{__MODULE__} was declared with, and key"
      @spec config(Vela.serie(), key :: atom(), default :: any()) :: Vela.option()
      def config(serie, key, default \\ nil), do: Keyword.get(@config[serie], key, default)

      use Vela.Access, @config
      @behaviour Vela

      @impl Vela
      def slice(vela),
        do: for({serie, [h | _]} <- vela, do: {serie, h})

      @impl Vela
      def purge(%__MODULE__{} = vela, validator \\ nil),
        do: Vela.purge(vela, validator)

      @impl Vela
      def delta(%__MODULE__{} = vela, comparator \\ nil),
        do: Vela.δ(vela, comparator)

      @impl Vela
      def equal?(%__MODULE__{} = v1, %__MODULE__{} = v2),
        do: Vela.equal?(v1, v2)
    end
  end
end