module advent_of_code.tasks.day_3.Star1

open System.IO

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

let getJoltage (line: string) =
    let firstDigit = List.max(Seq.toList(line[0 .. line.Length - 2]))
    let firstDigitPos = line.IndexOf firstDigit
    let secondDigit = List.max(Seq.toList(line[firstDigitPos + 1 ..]))
    $"{firstDigit}{secondDigit}" |> int

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

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