defmodule NDCEx.Message.Base do
  import XmlBuilder
  require Logger

  @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 [
                AirShopping: :CoreQuery,
                FlightPrice: [:Query, :DataLists, :Metadata],
                SeatAvailability: [:Query, :DataLists]
              ]

  def build_document(method, data, config) do
    [ndc_method, response_name] = get_request_data(method)
    build_ndc_body(ndc_method, data, config)
    |> generate
    |> add_soap_tags(config)
  end

  defp add_soap_tags(xml, config) do
    if config[:soap] == nil do
      xml
    else
      IO.puts("Adding SOAP wrapping...")
      first_char = String.at(xml, 0)
      last_char = String.at(xml, String.length(xml)-1)
      ns = config[:soap][:request_namespace]
      envelope_start = "<#{ns}:Envelope #{ config[:soap][:attributes][:envelope]}>"
      body_start = "<#{ns}:Body #{ config[:soap][:attributes][:body]}>"
      body_end = "</#{ns}:Body>"
      envelope_end = "</#{ns}:Envelope>"
      Enum.join([envelope_start, body_start, xml, body_end, envelope_end], "\n")
    end
  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 message_attributes(ndc_method, config) do
    config[:ndc][:attributes]
  end

  defp build_ndc_body(ndc_method, data, config) do
    tag_list = [:Document, :Party, :Travelers, :CoreQuery, :Preferences, :Metadata]
    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), message_attributes(ndc_method, config), elements)
  end

end