What style of karate is this?

i know this may be a stupid question but what fighting style is jackie chan using in the 1990's movie the legend of drunken master? i know its probably some form of drunken boxing but it just looks so refined and different from that when jackie is in his stance where he has one hand by his side and the other stretched out half way in front of him with his palm straight and facing himself. also as a side question what kind of stretches are good for increasing flexibility to learn a fighting style such as this or kung fu of some sort?