I recently got attacked by someone and they took all my resourcess.

800k+ of each.

I have level 7 walls and about 500 archer towers.

What's a good recommendation to be fully defended by an attack?

He had:

4500 workers
10000 warriors
3900 archers
127 transporters
50 ballista

I only killed a handful of workers. What level walls should I be and what should I stack defense-wise? I really can't stand losing all those resources so any help would be much appreciated.