Collections - indented based on folder hierachy

I'd like to show a brief collection on one page. the collection being a concise list of title and url for each of it's children. each level is indented like:

• folder 1
  -- folder 1, page 1
  -- folder 1, page 2
  -- folder1 subfolder 1
  --- folder1 subfolder 1, page 1
• folder 2
  -- folder 2 page 1
• folder 3

I tried loop.index (in my twig) as a means to determine depth, but that doesnt work as it increases all the time. I need a 'depth' variable, but cant find any not of this anywhere, so I think I am looking for the wrong word/s