I live west of Paris and I need 3-4 commutes to get to the average place in Paris. I looked for and then contemplated writing an app that would optimize a car

I live west of Paris and I need 3-4 commutes to get to the average place in Paris. I looked for and then contemplated writing an app that would optimize a car + public transportation route (exactly one of each) to park at a station relatively away from the city, and get closest to the destination in one train/metro ride (reasonable walking to the final destination is ok). This is because driving in Paris is a nightmare, and then finding a spot to park is a treasure hunt (except if you park underground - they have a facility to elegantly get your kindney to pay for the parking). I do not think it would be that difficult to write: the transport data is public and plentiful, openstreetmap has routing. I may get back to the idea someday.