defmodule Apostle.Queue do
  defstruct emails: []

  @moduledoc """
  Functions for working with `Apostle.Queue` structs, which represent a number of emails, all to be sent at once.
  """

  def init do
    %Apostle.Queue{}
  end

  def init %Apostle.Mail{}=mail do
    init [mail]
  end

  def init(mails) when is_list(mails) do
    Enum.reduce mails, init, fn(mail, queue)-> push queue, mail end
  end

  @doc """
  Push a mail onto the queue.
  """
  def push %Apostle.Queue{emails: emails}=queue, %Apostle.Mail{}=mail do
    Map.put queue, :emails, [mail | emails]
  end

  @doc """
  Deliver the contents of the queue via the Apostle API.
  """
  def deliver %Apostle.Queue{}=queue do
    payload = Poison.encode! queue

    HTTPoison.post Apostle.delivery_host, payload,
      content_type:   "application/json",
      apostle_client: "Elixir/#{Apostle.version}",
      authorization:  "Bearer #{Apostle.domain_key}"
  end
end