Unanswered: A comming of age, possibly made for TV movie, 80s/90s

There was a movie with two boys and two girls. Its plot took place in summer. One of the boys mother was present. I remember two things very well: the boys were smoking pot (they found cannabis growing wild next to a house); and (more to the end of the movie) a boy and a girl were playing strip poker / blackjack, the other two were kissing in a cave(?) - I think someone attacked them there. The movie ends when one of the boys (the one who's mother was present in it) was returning home (on a train?) and read a message from the other boy that there was only 300-something days left till summer. Simply put: a coming of age movie (possibly made for TV) with love and friendship. Anyone remembers the title?