Payment gateway and Price calculation

I have an android app that's like taxi booking app but slightly different. The backend is Firebase it's native app. I need these two things first the app should calculate price per trip based on distance to be traveled so you should have proper knowledge of google maps API. You should be able to calculate price for short distance n long distance the price. When you bid you should provide a strategy on how you will build that to an app. Secondly I need payment gateway integration there are three preferences stripe,payfast The user should pay with debit or credit card. You should have firebase experience and must speak english fluently