Use Power Query to create a custom 4-4-5 Calendar Table with offsets based on today

I am looking use Power Query to create a custom 4-4-5 Calendar table with offsets. I have attached an example of what I want as an excel file. Below are some of the "rules" that apply to the calendar and where I've struggled: (1) Weeks run from Sunday to Saturday (2) If Jan 1st falls between Sunday and Tuesday, the fiscal month [[login to view URL]] for January will end on the 4th Saturday. If Jan 1st falls between Thursday and Saturday, then January's [[login to view URL]] will end on the 5th Saturday. (3) There is a column that returns Today's fiscal month [[login to view URL]] as a number. For example, if today were April 29th, its fiscal month [[login to view URL]] would be 5 not 4. (4) Each year ends on December 31st (extra days from the 28day-28day-35day pattern are added into December (5) There are index numbers for each day/week/month of each year (6) The calendar runs from 2017 to 2020