module Day01
  ( day01_1,
    day01_2,
  )
where

parseInput :: IO [String]
parseInput = do
  lines <$> readFile "input/day1.txt"

rotate :: Int -> String -> Int
rotate n ('L' : xs) = (n - read xs) `mod` 100
rotate n ('R' : xs) = (n + read xs) `mod` 100
rotate n _ = n

rotate' :: Int -> String -> (Int, Int)
rotate' 0 ('L' : xs) = (negate (read xs) `mod` 100, (read xs + 100) `div` 100 - 1)
rotate' n ('L' : xs) = ((n - read xs) `mod` 100, (read xs - n + 100) `div` 100)
rotate' n ('R' : xs) = ((n + read xs) `mod` 100, (read xs + n) `div` 100)
rotate' n _ = (n, 0)

getPassword :: Int -> Int -> [String] -> Int
getPassword pass 0 [] = pass + 1
getPassword pass _ [] = pass
getPassword pass 0 (x : xs) = getPassword (pass + 1) (rotate 0 x) xs
getPassword pass curr (x : xs) = getPassword pass (rotate curr x) xs

getPassword' :: Int -> Int -> [String] -> Int
getPassword' pass _ [] = pass
getPassword' pass curr (x : xs) = getPassword' newPass newVal xs
  where
    (newVal, nZero) = rotate' curr x
    newPass = pass + nZero

day01_1 :: IO ()
day01_1 = do
  input <- parseInput
  let result = getPassword 0 50 input
  putStrLn $
    "Day 1, Puzzle 1 solution: "
      ++ show result

day01_2 :: IO ()
day01_2 = do
  input <- parseInput
  let result = getPassword' 0 50 input
  putStrLn $
    "Day 1, Puzzle 2 solution: "
      ++ show result