defmodule DaProductAppWeb.TransactionController do
  use DaProductAppWeb, :controller
  alias DaProductApp.Mypinpad
  require Logger

  @doc """
  Mypinpad Transaction Processing: POST /transaction/process
  """
  def create(conn, %{"transaction_id" => tx_id} = params) do
    # 1. Idempotency Check
    case Mypinpad.get_transaction_by_id(tx_id) do
      nil ->
        # 2. Process New Transaction
        # Here you would typically call your Acquirer/Bank API
        # We simulate a success with EMV data
        response_payload = %{
          "responseCode" => "00",
          "emvData" => "8A023030", # EMV approved code
          "authCode" => "OK" <> tx_id
        }

        with {:ok, _tx} <- Mypinpad.create_transaction(%{
               transaction_id: tx_id,
               payload: params,
               response: response_payload,
               status: "success"
             }) do
          conn
          |> put_status(:ok)
          |> json(response_payload)
        end

      existing_tx ->
        # 3. Return existing response (Retry handling)
        conn
        |> put_status(:ok)
        |> json(existing_tx.response)
    end
  end

  def create(conn, _params) do
    conn
    |> put_status(:bad_request)
    |> json(%{error: "missing_transaction_id"})
  end
end