module advent_of_code.tasks.day_1.Star1

open System.IO

let stream = new StreamReader("tasks/day-1/input.txt")

let diff (line: string) =
    let direction = if line.StartsWith("R") then 1 else -1
    let count = (line.[1..] |> int)
    direction * count
    
let solve (line: string) (start: int) =
    let change = diff line
    let newPos = (start + change) % 100
    (newPos, if newPos = 0 then 1 else 0)

let rec main start zeroes =
    let line = stream.ReadLine()
    let newPos, newZeroes = solve line start
    if stream.EndOfStream then
        (newPos, zeroes + newZeroes)
    else
        main newPos (zeroes + newZeroes)