free_shipping.rb

class Calculator::FreeShipping < Calculator
  preference :threshold, :decimal, :default => 0

  def available?(order)
    order.item_total >= self.preferred_threshold    
  end

  def self.description
    I18n.t("free_shipping")
  end

  def self.register
    super
    ShippingMethod.register_calculator(self)
  end

  def compute(object=nil)
    0.0
  end
end