What should I eat before, during and after exercise?

This is very individual. For most people, however, it is sufficient to eat 2-3 hours before exercise. Try also to test an apple or a handful of nuts a half hour or so before training. It is time to adjust habits if you are one of them who eats a lot in a short time before training. There is otherwise a risk that you feel sick and get cramps in the muscles during exercise. It is almost worse to exercise on an empty stomach. When you start to work out the blood sugar drops and you will feel weaker, a little dizzy, and do less. To train with too little food in the body increases also the risk of injury significantly.

Not much before, nothing during, and whatever you like afterwards. 

water must . 

then any fruit or low calory food 

If you eat before or during exercise, the food will not digest properly.  This will lead to uncontrollable continuous farting.  If you're in a public gym, this will not be appreciated and may result in you receiving a beating.

Anything that's healthy, it's up to you.

probably whatever you want to eat

Food comes to mind.   Junk will only make you fatter, but exercise has almost nothing to do with significant fat loss or gain,  so that may not be your goal.

Not right before.  

It depends on what your fitness goals are.  Mostly you should just eat a balanced diet whenever you feel like it.  The obsession with pre and post workout meals is mostly a lot of fuss about nothing.  It doesn't really matter when you eat.  Well it does if you are doing intermittent fasting, which is a good idea IMHO, but other than that eat when you feel like it.