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, params) do
    [request_name, response_name] = get_request_data(method)
    build_body(request_name, params[:ndc])
    |> generate
    |> add_soap_tags(params)
  end

  defp add_soap_tags(xml, params) do
    if params[:soap] == nil do
      xml
    end

    first_char = String.at(xml, 0)
    last_char = String.at(xml, String.length(xml)-1)

    ns = params[:soap][:namespace]
    envelope_start = "<#{ns}:Envelope #{ params[:soap][:attributes][:envelope]}>#{first_char}"
    body_start = "<#{ns}:Body>"
    body_end = "</#{ns}:Body>"
    envelope_end = "</#{ns}:Envelope>"
    Enum.join([envelope_start, body_start, xml, body_end, envelope_end], "\n")
  end
  defp get_request_data(method), do: @acceptable_ndc_methods[method]
  defp document_attributes(request_name) do
    %{
      "xmlns" => "http://www.iata.org/IATA/EDIST",
      "xmlns:xsi" => "http://www.w3.org/2001/XMLSchema-instance",
      "xsi:schemaLocation" => "http://www.iata.org/IATA/EDIST ../#{request_name}.xsd",
      "Version" => "15.2"
    }
  end

  defp build_body(request_name, params) do
    element(String.to_atom(request_name), document_attributes(request_name), [
        element(Document: params[:Document]),
        element(Party: params[:Party]),
        element(Parameters: params[:Parameters]),
        element(Travelers: [params[:Travelers]]),
        element(CoreQuery: [params[:CoreQuery]]),
        element(Preferences: params[:Preferences])
      ]
    )
  end
end