public void UpdateProduct(Product product)
{
if (product.Id == null)
{
throw new InvalidOperationException("cannot update a new product");
}
var productId = product.Id.GetValueOrDefault();
product.CreateCheckPoint();
var keyToRemove = product.CheckPointHistory.Last().Key;
// cloning the object to separate it from the original - thereby simulating a real-life data insertion
var clone = (Product)product.CurrentCheckPoint;
if (!ProductData.ContainsKey(productId))
{
throw new InvalidOperationException("product not found");
}
ProductData[productId] = clone;
//get rid of checkpoint
product.CheckPointHistory.Remove(keyToRemove);
}