Srilanka can still win this match pretty easily. There are still five sessions left in the match and they have to take nine more wickets in these sessions. the only hope for Bangladesh is to avoid losing wickets and see where they stand by the lunch on the 5th day. If they have wickets in hand at that time, they could take on this chase against srilanka at that moment.
They have scored 177 runs before the match is delayed due to bad light. Although i am not watching this match, but i wish if somehow a miracle happens and Bangladesh does won this one. If they had batted a bit better, they would have been in a much better position.