// Before: Long method
function processOrder(order) {
  // Validate order
  if (!order.customer) {
    throw new Error('Customer required');
  }
  if (!order.items || order.items.length === 0) {
    throw new Error('Items required');
  }
  if (order.total <= 0) {
    throw new Error('Invalid total');
  }

  // Calculate discounts
  let discount = 0;
  if (order.customer.vip) {
    discount += order.total * 0.1;
  }
  if (order.total > 1000) {
    discount += order.total * 0.05;
  }

  // Apply tax
  const tax = (order.total - discount) * 0.08;
  const finalTotal = order.total - discount + tax;

  // Update inventory
  order.items.forEach(item => {
    const product = findProduct(item.productId);
    if (product.stock < item.quantity) {
      throw new Error('Insufficient stock');
    }
    product.stock -= item.quantity;
  });

  // Save order
  const savedOrder = database.save(order);

  // Send confirmation
  emailService.send(order.customer.email, 'Order confirmation');

  return savedOrder;
}