Eligible promotions are excluded from tax Warning: Only works if you have one Tax category

Calculator::CanadianTax

require_dependency 'spree/calculator'

module Spree
  class Calculator::CanadianTax < Calculator::DefaultTax
    def self.description
      "Canadian tax (Eligible promotions are excluded from tax)"
    end

    private

    def compute_order(order)
      matched_line_items = order.line_items.select do |line_item|
        line_item.product.tax_category == rate.tax_category
      end

      line_items_total = matched_line_items.sum(&:total)

      #This returns a negative amount!
      promotion_adjustments_total = order.adjustments.eligible.promotion.sum(&:amount)

      total = promotion_adjustments_total + line_items_total
      round_to_two_places(total * rate.amount)
    end


    #def compute_order(order)
    #  matched_line_items = order.line_items.select do |line_item|
    #    line_item.product.tax_category == rate.tax_category
    #  end
    #
    #  line_items_total = matched_line_items.sum(&:total)
    #  round_to_two_places(line_items_total * rate.amount)
    #end
  end
end