gistfile1.txt

class Shop
  class Warehouse
    def self.find(id)
      Product.find_by_id(id)
    end
  end

  class Customer
    attr_reader :user

    def self.find(id)
      User.find_by_id(id)
    end

    def initialize(user)
      @user = user
    end

    def pay(product)
      # perform the payment
    end
  end

  class Transaction
    attr_reader :customer, :product, :order, :status

    def initialize(customer, product)
      @customer = customer
      @product  = product
    end

    def commit
      @status = customer.pay(product)

      if success?
        commit!
      end
    end

    def commit!
      create_order

      if order.persisted?
        mark_product_as_sold
      end
    end

    def success?
      status === true
    end

    private

    def create_order
      @order = Order.create(:user => customer, :product => product)
    end

    def mark_product_as_sold
      @product.update_attribute(:sold, true)
    end
  end
end