You should eat carbs before a match along with a lot of water. Just before you start to warm up a few jelly beans or something similar are good though. You want a small burst of sugar before you go on.

They're not the best things to eat before a rugby match, but in the grand scheme of things, it won't.

Not really.

ofcoz it can affect your mood.energy bar and energy drink recommended

You might get kinda sick...