defmodule Xend.Base do

  @moduledoc false

  use HTTPoison.Base

  @fb_page_access_token Application.get_env(:xend, :fb_page_access_token)
  @base_url "https://graph.facebook.com/v2.6/me/messages"
  
  def post(body) do
    payload = Poison.encode!(body)

    post!(url(), payload, headers())
    |> process_response
  end

  def process_response_body(body), do: Poison.decode!(body)

  def process_response(%HTTPoison.Response{status_code: 200, body: body}), do: body
  def process_response(%HTTPoison.Response{status_code: code, body: body}), do: {code, body}
  
  defp headers(), do: ["Content-Type": "application/json"]
  defp url(), do: @base_url <> "?access_token=#{@fb_page_access_token}"
end