module Shopper
  class OrderItem < ApplicationRecord
    include Shopper::OrderItemArithmeticHelpers

    belongs_to :order
    belongs_to :product, polymorphic: true

    validates :order, :product, :quantity, presence: true
    validates :quantity, numericality: {
      only_integer: true,
      greater_than_or_equal_to: 1
    }

    def to_s
      "#{quantity} #{product}"
    end
  end
end