Contents

module Spree

  # A calculator for promotions that calculates a percent-off discount
  # for all matching products in an order. This should not be used as a 
  # shipping calculator since it would be the same thing as a flat percent
  # off the entire order.
  
  class Calculator::PercentPerItem < Calculator
    preference :percent, :decimal, :default => 0

    attr_accessible :preferred_percent

    def self.description
      I18n.t(:percent_per_item)
    end

    def compute(object=nil)
      return 0 if object.nil?
      object.line_items.reduce(0) do |sum, line_item|
        sum += value_for_line_item(line_item)
      end
    end

  private

    # Returns all products that match the promotion's rule. 
    def matching_products
      @matching_products ||= if compute_on_promotion?
        self.calculable.promotion.rules.map(&:products).flatten
      end
    end

    # Calculates the discount value of each line item. Returns zero 
    # unless the product is included in the promotion rules.
    def value_for_line_item(line_item)
      if compute_on_promotion?
        return 0 unless matching_products.blank? or matching_products.include?(line_item.product)
      end
      line_item.price * line_item.quantity * preferred_percent
    end

    # Determines wether or not the calculable object is a promotion
    def compute_on_promotion?
      @compute_on_promotion ||= self.calculable.respond_to?(:promotion)
    end

  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
spree_promo-1.3.3	app/models/spree/calculator/percent_per_item.rb