[TYPO3-mvc] Extbase Domain-Service

[Thomas "Thasmo" Deinhamer]

Good evening!

Regarding DDD I read that processes that don't belong to
the domain of a model or a repository, could or should
be handled by services - which are also available in Extbase.

I'd like to calculate the current stock amount of a product,
based on several circumstances, like a number of products
which are not available or another number of products which
are on reapair etc.

Furthermore I need to predict the available stock amount
also based on a given, specific date.

The predicted stock amount for a specific date should then
be displayed in the frontend.

How can this be done? Do I need a service for this, or can
this be handled inside the product model or the controller?

Thanks a lot,
Thomas