class CartItem < ActiveRecord::Base
  belongs_to :cart
  belongs_to :product

  delegate :name, :to => :product

  def increment_quantity(increment)
    self.quantity += increment
  end

  def quantity=(quantity)
    if quantity < 1
      self.remove_from_cart!
    else
      write_attribute(:quantity, quantity)
    end
  end

  def shipping_weight
    self.product.shipping_weight * self.quantity
  end

  def remove_from_cart!
    self.destroy()
  end

  # Price per unit
  def unit_price  ; self.product.price ; end
  def unit_pricef ; Cart.format_price(self.unit_price()) ; end

  # Total price
  def price  ; self.product.price * self.quantity ; end
  def pricef ; Cart.format_price(self.price()) ; end

  # needed for rails magic form_for stuff, so DO NOT change this to some debug/display value
  def to_s
    self.product_id
  end
end