defmodule KeenAuth.EmailAuthenticationController do
  alias KeenAuth.Mapper
  alias KeenAuth.Storage
  alias KeenAuth.Processor
  alias KeenAuth.EmailAuthenticationHandler

  use Phoenix.Controller

  defmacro __using__(_opts \\ []) do
    quote do
      use Phoenix.Controller

      @behaviour unquote(__MODULE__)

      def new(conn, params), do: unquote(__MODULE__).new(conn, params)
      # def delete(conn, params), do: unquote(__MODULE__).delete(conn, params)

      defoverridable unquote(__MODULE__)
    end
  end

  # TODO Throttling
  def new(conn, params) do
    provider = :email

    with {:ok, raw_user} <- EmailAuthenticationHandler.authenticate(conn, params),
         response = %{user: raw_user, tokens: nil},
         mapped_user = Mapper.current_mapper(conn, provider).map(provider, raw_user),
         {:ok, conn, user, result} <- Processor.process(conn, provider, mapped_user, response),
         {:ok, conn} <- Storage.store(conn, provider, user, result) do
      EmailAuthenticationHandler.handle_authenticated(conn, user)

      conn
      |> redirect_back(params)
    else
      err ->
        Process.sleep(Enum.random(100..300//10))
        # Sleep for random amount to prevent timing attacks

        EmailAuthenticationHandler.handle_unauthenticated(conn, params, err)
    end
  end

  # def delete(conn, params) do
  #   storage = Storage.current_storage(conn)

  #   with user when not is_nil(user) <- storage.current_user(conn) do
  #     conn
  #     |> storage.delete()
  #     |> redirect_back(params)
  #   else
  #     nil ->
  #       redirect_back(conn, params)
  #   end
  # end

  @spec redirect_back(Plug.Conn.t(), map()) :: Plug.Conn.t()
  def redirect_back(conn, params \\ %{}) do
    redirect_to =
      get_session(conn, :redirect_to) ||
        params["redirect_to"] ||
        "/"

    conn
    |> delete_session(:redirect_to)
    |> redirect(external: redirect_to)
  end
end