defmodule NDCEx.Message.Base do
  import XmlBuilder
  require Logger
  use Timex

  @acceptable_ndc_methods [
                            AirShopping: ["AirShoppingRQ", "AirShoppingRS"],
                            FlightPrice: ["FlightPriceRQ", "FlightPriceRS"],
                            SeatAvailability: ["SeatAvailabilityRQ", "SeatAvailabilityRS"],
                            ServiceList: ["ServiceListRQ", "ServiceListRS"],
                            ServicePrice: ["ServicePriceRQ", "ServicePriceRS"],

                            OrderCreate: ["OrderCreateRQ", "OrderViewRS"],
                            OrderList: ["OrderListRQ", "OrderListRS"],
                            OrderRetrieve: ["OrderRetrieveRQ", "OrderViewRS"],
                            OrderCancel: ["OrderCancelRQ", "OrderCancelRS"]
                          ]
  @node_names [
                AirShoppingRQ: [:CoreQuery, :Preferences, :Metadata],
                FlightPriceRQ: [:Query, :Metadata, :DataLists],
                SeatAvailability: [:Query, :DataLists]
              ]

  def build_document(method, data, config) do
    [ndc_method, response_name] = get_request_data(method)
    body = build_ndc_body(ndc_method, data, config)
    |> generate
    |> add_soap_tags(config[:soap])
    {body, Time.now}
  end

  defp add_soap_tags(xml, config) when config == nil, do: xml
  defp add_soap_tags(xml, config) do
    ns = config[:request_namespace]

    attribute = String.replace(config[:attributes][:envelope], "{namespace}", ns)
    envelope_start = "<?xml version=\"1.0\" ?>\n<#{ns}:Envelope #{attribute}>"
    body_start = "<#{ns}:Body #{ config[:attributes][:body]}>"
    body_end = "</#{ns}:Body>"
    envelope_end = "</#{ns}:Envelope>"
    Enum.join([envelope_start, body_start, xml, body_end, envelope_end], "\n")
  end

  def build_url(url, method), do: String.replace(url, "{{NDC-method}}", Atom.to_string(method))
  defp get_request_data(method), do: @acceptable_ndc_methods[method]

  defp build_ndc_body(ndc_method, data, config) do
    ndc = String.to_atom(ndc_method)
    tag_list = [:Document, :Party, :Travelers ] ++ @node_names[ndc]
    elements = [
      Enum.filter(tag_list, fn(tag) -> data[tag] != nil end)
      |> Enum.map( fn(tag) ->
            element(tag, data[tag])
        end)
    ]
    element(String.to_atom(ndc_method), config[:ndc][:attributes], elements)
  end

end