Date Granularity

Hi everyone. I am working on a dashboard that shows contracts and sales by averages and I have created a list of "Quick Date" options that have preset granularities to them and then a custom option that will dynamically change the granularity based on the difference of days.
However, I am wanting it to be basically totally dynamic to the point where the user can select any quick date option or a custom range but ALSO pick the granularity (daily, weekly, monthly, yearly). Does anyone have an idea on this? I had an idea to apply the granularity to a report range measure that would reflect the range of dates the user chooses but I have yet to figure that out. 

If anyone has an idea let me know!