#use "lib/utils.ml" ;;

let parse_range str =
  let nums = String.split_on_char '-' str in
  let start = int_of_string (List.nth nums 0) in
  let rend = int_of_string (List.nth nums 1) in
  (start, rend)
in

let is_full_overlap x y =
  let ((x1, x2), (y1, y2)) = (x, y) in
  (x1 >= y1 && x2 <= y2) || (y1 >= x1 && y2 <= x2)
in

let is_partial_overlap x y =
  let ((x1, x2), (y1, y2)) = (x, y) in
  not (x1 > y2 || x2 < y1)
in

let count_overlaps lines fn =
  let check_overlap line =
    let ranges = String.split_on_char ',' line in
    let left = parse_range (List.nth ranges 0) in
    let right = parse_range (List.nth ranges 1) in
    if fn left right then 1 else 0
  in
  List.map check_overlap lines
  |> List.fold_left (+) 0
in

let contents = read_file "inputs/4.txt" in
let lines = String.split_on_char '\n' contents
|> List.filter (fun l -> String.trim l <> "")
in
let nfull = count_overlaps lines is_full_overlap in
let npartial = count_overlaps lines is_partial_overlap in
Printf.printf "%d full overlaps\n" nfull;
Printf.printf "%d partial overlaps\n" npartial