vatchex_greece

# SPDX-FileCopyrightText: 2023 Isaak Tsalicoglou <isaak@waseigo.com>
# SPDX-License-Identifier: Apache-2.0

defmodule VatchexGreece.Request do
  require EEx

  @moduledoc """
  Prepare and post a request to the SOAP web service.
  """
  @moduledoc since: "0.2.0"

  @gsis_wsdl_url "https://www1.gsis.gr/wsaade/RgWsPublic2/RgWsPublic2?wsdl"

  @doc """
  Prepare the request's XML template based on the VAT ID you call for),
  and authentication settings (username, password, VAT ID you call from).
  """
  @doc since: "0.5.0"
  # statically compile the XML request template and create a function to customize it
  EEx.function_from_file(
    :def,
    :to_xml,
    "lib/request.xml.eex",
    [:afm_called_for, :username, :password, :afm_called_by]
  )

  def prepare({:ok, %Results{auth: auth, data: data} = input}) do
    xml =
      to_xml(
        data.afm,
        auth.username,
        auth.password,
        auth.afm_called_by
      )

    {:ok, %Results{input | request: xml}}
  end

  def prepare({:error, input}) do
    {:error, input}
  end

  @doc """
  POST the XML request with proper headers to the SOAP web service.
  """
  @doc since: "0.5.0"
  def post({:ok, %Results{request: xml, errors: errors} = input}) do
    response =
      HTTPoison.post(
        @gsis_wsdl_url,
        xml,
        %{"Content-Type" => "application/soap+xml"}
      )

    case response do
      {:error, http_response} ->
        errors =
          Map.put(
            errors,
            :http_request_error,
            "HTTP request error."
          )

        {:error, %Results{input | response: http_response, errors: errors}}

      {:ok, http_response} ->
        case http_response.status_code do
          200 ->
            handle_status_200(input, http_response)

          _ ->
            errors =
              Map.put(
                errors,
                :http_not_OK,
                "HTTP status code #{http_response.status_code} (not OK)."
              )

            {:error, %Results{input | response: http_response, errors: errors}}
        end
    end
  end

  def post({:error, input}) do
    {:error, input}
  end

  # refactored function to void 3-levels-deep case handling in post/1
  defp handle_status_200(%Results{errors: errors} = input, http_response) do
    if String.contains?(
         http_response.body,
         "RG_WS_PUBLIC_TOKEN_USERNAME_NOT_AUTHENTICATED"
       ) do
      errors = Map.put(errors, :authentication_error, "Authentication error.")
      {:error, %Results{input | response: http_response, errors: errors}}
    else
      {:ok, %Results{input | response: http_response}}
    end
  end
end