require HTTPoison

defmodule Apostle do
  alias Application, as: App
  use App, otp_app: :apostle

  @moduledoc """
  Elixir client for Apostle.io.

  The `Apostle` module can be used to queue messages for delivery via the Apostle API.

      iex> Apostle.deliver email: "test@example.com", template_id: "welcome", name: "Mr Example"

  Under the hood Apostle uses [HTTPoison](https://github.com/edgurgel/httpoison)
  to issue HTTP requests to the Apostle API.
  """

  def start _type, _args do
    start
  end

  def start do
    HTTPoison.start
  end

  def delivery_host do
    App.get_env :apostle, :delivery_host, default_delivery_host
  end

  def domain_key do
    App.get_env :apostle, :domain_key, default_domain_key
  end

  @doc ~S"""
  Delivers a queue of messages via the API.
  """
  def deliver %Apostle.Queue{}=queue do
    Apostle.Queue.deliver queue
  end

  @doc ~S"""
  Delivers a single mail via the API.
  """
  def deliver %Apostle.Mail{}=mail do
    Apostle.Queue.deliver Apostle.Queue.init(mail)
  end

  @doc ~S"""
  Generates and delivers a single mail via the API.
  """
  def deliver opts do
    mail  = Apostle.Mail.init opts
    queue = Apostle.Queue.init mail
    Apostle.Queue.deliver queue
  end

  def version do
    Dict.get Apostle.Mixfile.project, :version
  end

  defp default_delivery_host do
    host = System.get_env "APOSTLE_DELIVERY_HOST"
    if host do
      host
    else
      "http://deliver.apostle.io"
    end
  end

  defp default_domain_key do
    key = System.get_env "APOSTLE_DOMAIN_KEY"
    if key do
      key
    else
      raise "Either set :domain_key in the application's configuration or the APOSTLE_DOMAIN_KEY environment variable"
    end
  end
end