class Cart < ActiveRecord::Base
  has_many :item_in_carts, -> { order "created_at" }
 
  def self.find_or_create(anonymous_id, user_id)
    cart = Cart.where(user_id: user_id).where(ordered: false).first
    cart ||= Cart.where(anonymous_id_string: anonymous_id).where(ordered: false).first
    safe_user_id = (user_id > 0) ? user_id : nil
    cart ||= Cart.create!(anonymous_id_string: anonymous_id, user_id: safe_user_id, ordered: false )
  end
end