tax.rb

module TaxServices
  class ItemPrice
    def initialize(total_price, has_tax, has_service_tax)
      @total_price = total_price
      @service_tax_rate = has_tax ? Settings.tax.service_tax_rate : 0
      @tax_rate = has_service_tax ? Settings.tax.tax_rate : 0
    end

    def perform
      OpenStruct(
        item_price: item_price,
        tax: tax,
        service_tax: service_tax
      )
    end

    def item_price
      @item_price ||= @total_price / ((1 + @service_tax_rate) * (1 + @tax_rate))
    end

    def service_tax
      item_price  * @service_tax_rate
    end

    def tax
      (item_price + service_tax) * @tax_rate
    end
  end
end