module advent_of_code.tasks.day_3.Star2

open System.IO

let stream = new StreamReader("tasks/day-3/input.txt")

let rec getJoltage (line: string) (count: int) =
    let firstDigit = List.max(Seq.toList(line[0 .. line.Length - (count)]))
    let firstDigitPos = line.IndexOf firstDigit
    if count = 1 then
        $"{firstDigit}" |> int64
    else
        $"{firstDigit}{getJoltage line[firstDigitPos + 1 ..] (count - 1) }" |> int64

let rec mainLoop (lines: string list) =
    let line, tail = lines.Head, lines.Tail
    let joltage = getJoltage line 12
    if (tail.IsEmpty) then
        joltage
    else
        joltage + mainLoop tail

let rec main =
    let lines = stream.ReadToEnd().Split("\n") |> Array.toList
    mainLoop lines