Script - Rename folder based on the type and quantity of its content

Hello
I have read several forum posts but I don't think I can find the solution to my problem. I want the folder of a series to show in its name the number of chapters it has inside it, and the total weight. An example of an expected result would be: Blindspot - [Temp 5] [Cap-11] [3.43 GB].

Since I know some JS, I try to understand the syntax that the program processes, to be able to create a script, but I can't find a method to enter and read the contents of the folder, to create a counter from item.videoExists ... They are ideas, I would appreciate any help or suggestion