Camera takes pictures automatically when switch

The first thing you should do if your camera (or any electronic device) is submerged or becomes so wet that it doesn't operate properly is TAKE THE BATTERIES OUT. This avoids further damage to electronic circuits due to corrosion caused by electrical current flow. You may not avoid all damage and your camera might need a cleaning of the optical components but you might be pleasantly surprised to find that the electronics work properly after a prolonged period (1 week ?) of drying out.

There is left-over water damage, which is never good news. Every switch contact inside the camera will have to cleaned as well as it can be. It sounds like the camera is still working, but the switches have corrosion, causing them to short and automatically cause the camera to turn on. You can try to disassemble the camera, and clean them, but it will not be easy. Often, water damage cannot be totally reversed, but in this case you might be able to salvage the camera. Most of the time, even a warranty will not cover water damage, so you have no choice but to try to fix it yourself or get it serviced. Make sure you get an estimate before you have it serviced, since the cost can be considerable. Wish I had better news for you.