Calculator built useing python

I want a calculator that takes the past data of the S&P500 on every Friday at the market open And adds X amount of money to an account. I also it needs to be able to be pasted into a website and full intellectual rights in owning the finished product required. —————- Example: if I started investing $100 in the S&P500 every Friday starting on February 5th 1982. What would my acount growth look like? (s&p500 = $400 per share/$100 invested = 0.25 of a share. [Always round Down on 9th decimal] ).—————- Variables A= date start B= date end ( if blank the most previous Friday ) C= Amount of money invested every week D= percentage increase in principle each year ( if blank none increase).—————- Results displayed as a yearly breakdown. 1982: Total Principle invested, Current evaluation of shares Growth on principle overall in % 1983: Principle invested, Current evaluation of shares , Growth on principle overall in % 1984: Principle invested, Current evaluation of shares , Growth on principle overall Etc.. to current date