defmodule Dagger.Codegen.Elixir.Function do
  @moduledoc false

  def format_module_name(name) when is_binary(name) do
    name
    |> Macro.camelize()
    |> String.to_atom()
  end

  def format_var_name(name) when is_binary(name) do
    format_name(name)
  end

  defp format_fun_name(name) when is_atom(name) do
    name
    |> to_string()
    |> format_fun_name()
  end

  defp format_fun_name(name) when is_binary(name) do
    format_name(name)
  end

  defp format_name(name) when is_binary(name) do
    name
    |> Macro.underscore()
    |> String.to_atom()
  end

  def define(fun_name, args, guard \\ nil, body, opts \\ []) when is_list(args) do
    fun_name = format_fun_name(fun_name)
    doc = opts[:doc] |> doc_to_quote()
    deprecated = opts[:deprecated] |> deprecated_to_quote()

    fun = [
      case guard do
        nil ->
          quote do
            def unquote(fun_name)(unquote_splicing(args)) do
              unquote(body)
            end
          end

        guard ->
          quote do
            def unquote(fun_name)(unquote_splicing(args)) when unquote(guard) do
              unquote(body)
            end
          end
      end
    ]

    quote do
      (unquote_splicing(doc ++ deprecated ++ fun))
    end
  end

  defp doc_to_quote(nil) do
    [
      quote do
        @doc false
      end
    ]
  end

  defp doc_to_quote(doc) when is_binary(doc) do
    [
      quote do
        @doc unquote(doc)
      end
    ]
  end

  defp deprecated_to_quote(nil), do: []

  defp deprecated_to_quote(deprecated) do
    [
      quote do
        @deprecated unquote(deprecated)
      end
    ]
  end
end