What is the difference between Audi A4 TFSI and TDI engines?

I am looking to buy an Audi A4 but I'm not sure which engine option is best. Can someone explain the difference between the TFSI and TDI engines and which one would be better suited for my needs?

The TFSI engine is a gasoline engine, while the TDI is a diesel engine. Gasoline engines typically have better performance and are more suitable for city driving, while diesel engines are more efficient and better for long distance driving. It ultimately depends on your driving habits and preferences.