Diet novel on coke.
I believe that default trending is still based on views, is it not?
The current trending? No. Nobody knows the math that goes into it. That is by design.
But only views are not enough. Nor readers, likes, or comments. My guess is that it is a mix of all the stats and their daily rise compared in a defined time frame. Probably taking up a whole month's worth of results.
I am 90% sure the algorithm does take time into consideration and aggregates your stats of likes, comments, and clicks, comparing them to your previous numbers to decide if you get to the top 10 of "rising" novels.
For example, someone I follow had a 3-4 month hiatus. The moment she came back, her book was trending as her released chapters got the views from us readers, and compared to her low interactions while being absent, it made the book trend.
But that is just a theory. A trending theory.