# frozen_string_literal: true

class OrderPaymentFinder
  def initialize(order)
    @order = order
  end

  def last_payment
    last(@order.payments)
  end

  def last_pending_payment
    last(@order.pending_payments)
  end

  private

  # `max_by` avoids additional database queries when payments are loaded
  # already. There is usually only one payment and this shouldn't cause
  # any overhead compared to `order(:created_at).last`. Using `last`
  # without order is not deterministic.
  #
  # We are not using `updated_at` because all payments are touched when the
  # order is updated and then all payments have the same `updated_at` value.
  def last(payments)
    payments.max_by(&:created_at)
  end
end