Is it possible to implement training plan import via iCal?

Question

Calendar

Sawing a site for one trainer, sells training plans. An idea came to mind: what if, in addition to a pdf with a plan, the buyer receives a file to import the plan into a google or apple calendar or any other.
But it is not entirely clear whether this can be implemented, because. the plan has no dates, only days of the week and a certain number of days/weeks. Each day has its own workout plan.
Is it possible to import without dates? Or the user can first ask the start date for the plan, then automatically fill in the missing dates in the file and send it to him, or immediately open it and upload it to the calendar via api.