Dealing with Feature Envy

gistfile1.rb

# Source: https://gist.github.com/4172391#gistcomment-610165

class Order
  def complete_purchase(purchase)
    purchase.complete(credit_card, amount)
  end

  def purchase_completed(transaction_reference)
    update_attibutes(:transaction_reference => transaction_reference)
  end

  def purchase_failed(error_message)
    # error handling
  end
end

class Purchase
  def initialize(order)
    @order = order
  end

  def submit
    order.complete_purchase(self)
  end

  def complete(credit_card, amount)
    result = Braintree::Transaction.sale(amount: @amount, credit_card: @credit_card)
    if result.success?
      order.purchase_succeeded(result.transaction_reference)
    else
      order.purchase_failed(result.error)
    end
  end
end