Is there an API to get the planned hours for an employee a particular day?

If I want to warn an employee that they shouldn't be working today because they have taken as vacation, I can't find an API that will tell me that (although the UI will show 0 planned hours).

attendance/estimated_times unfortunately doesn't take leaves into account.

The only other way i could think of was to actually look at the leaves and see if there are any that are active that day, then see if they are non-work leaves but that seems like a hassle.