module Day10 where
import System.IO (openFile, IOMode (ReadMode), hClose, hGetContents)
import Data.Maybe (mapMaybe)

closing :: Char -> Char
closing '(' = ')'
closing '[' = ']'
closing '{' = '}'
closing '<' = '>'

score :: Char -> Int
score ')' = 3 
score ']' = 57
score '}' = 1197
score '>' = 25137


matchBraces :: [Char] -> [Char] -> Maybe Char
matchBraces _ [] = Nothing
matchBraces acc (x:xs)
    | x `elem` ['(', '[', '{', '<'] = matchBraces (closing x : acc) xs
    | x == head acc = matchBraces (tail acc) xs
    | otherwise = Just x 

main :: IO ()
main = do
    input <- openFile "inputs/10.txt" ReadMode
    contents <- hGetContents input

    let routes = lines contents
    print . sum . map score $ mapMaybe (matchBraces []) routes

    hClose input