Smoker trying to gain weight

Hi I am 28 male and been desperately trying to gain weight, my bodytype is more of an ectomorph, i do workout and i eat very good and I also smoke a pack a day or maybe two for the past eight years. I need answers please if you think that smoking could affect my body of gaining weight. I understand that because of my bodytype (hardgainer) is very difficult to put on weight-mass but i have this feeling that smoking is making it even worse and i really want to quit this very bad habbit for many reasons regarding my health and i hope i could also get a few pounds when i quit and my appettite to increase a bit. I am not english and i'm sorry if my english are bad. Thank you very much for your replies.