{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE MultiWayIf #-}
module Main where

import Data.Functor

data Rotation where
  RRight :: Int -> Rotation
  RLeft :: Int -> Rotation

parse :: String -> [Rotation]
parse = map (\case
                ('R':xs) -> RRight (read xs :: Int)
                ('L':xs) -> RLeft (read xs :: Int)
                _        -> error "") . lines

solver :: Bool -> [Rotation] -> Int
solver b = go 50
  where go :: Int -> [Rotation] -> Int
        go _ [] = 0
        go curr (RRight n : xs) =
          let (rots,newCurr) = bound (curr + n) in
            (if | b -> (rots+)
                | newCurr == 0 -> (1+)
                | otherwise -> id) $ go newCurr xs
        go curr (RLeft  n : xs) =
          let (rots,newCurr) = bound (curr - n) in
            (if | b -> (rots+)
                | newCurr == 0 -> (1+)
                | otherwise -> id) $ go newCurr xs

        bound :: Int -> (Int,Int)
        bound x
                | x < 0 = (\(n,y) -> (n+1,y)) . bound $ x + 100
                | x > 99 = (\(n,y) -> (n+1,y)) . bound $ x - 100
                | otherwise = (0, x)

main :: IO ()
main = readFile "inputs/1" <&> parse >>= \i ->
       print (solver False i) >>
       print (solver True i)