defmodule DaProductApp.Utils.TxnRefGenerator do
  @moduledoc """
  Utility module for generating unique transaction reference numbers (txnRefNo).
  
  Generates random numeric transaction reference numbers in the format:
  - 11 digits long
  - Starts with "98" 
  - Followed by 9 random digits
  
  Example: "98050000009"
  """

  @doc """
  Generates a unique transaction reference number.
  
  Returns a string in the format "98XXXXXXXXX" where X are random digits.
  """
  def generate_txn_ref_no do
    # Generate 11 random digits (0-9)
    random_digits = 
      1..11
      |> Enum.map(fn _ -> :rand.uniform(10) - 1 end)
      |> Enum.join("")

    random_digits
  end
end