defmodule PowerDNSex.Config do
  defstruct [:url, :token, timeout: 60]

  alias PowerDNSex.Config

  def data do
    set_attr_value = &Map.update!(&2, &1, get_key(&1))

    %Config{}
    |> Map.from_struct()
    |> Map.keys()
    |> Enum.reduce(%Config{}, set_attr_value)
  end

  def powerdns_url do
    url = data().url
    if String.ends_with?(url, "/"), do: url, else: url <> "/"
  end

  def powerdns_token, do: data().token

  def powerdns_timeout, do: :timer.seconds(data().timeout)

  def valid?(), do: powerdns_url() && powerdns_token()

  ###
  # Private
  ###

  defp get_key(key) do
    fn default ->
      case Application.fetch_env(:powerdnsex, key) do
        {:ok, {:system, env_var_name}} ->
          System.get_env(env_var_name)

        {:ok, value} ->
          value

        _ when default != nil ->
          default

        _ ->
          raise "[PowerDNSex] PowerDNS #{Atom.to_string(key)} not configured."
      end
    end
  end
end