Pre select first in stock variation

The problem with woocommerce is that you have to manually preselect a variation. This can be a nightmare if you have hundreds of products. Add to the problem, what if the selected variation goes out of stock, this will cause terrible UX for the user. What if we could auto pre-select variations that are in stock. However, snippet must be performance oriented too (for example if there are 100 variations, it should not make 100 queries in real time on every product page load to scan stock status of every variation)