import Data.Char
import Control.Monad

total :: Int
total = 100

isDigitOrMinus :: Char -> Bool
isDigitOrMinus c = isDigit c || c == '-'

parse :: [String] -> [Int]
parse [_,_,a,_,b,_,c,_,d,_,e] = map (read . takeWhile isDigitOrMinus) [a,b,c,d,e]

getall :: [[Int]] -> [Int]
getall ing = map fst $ filter cal500 $ map computescore $ allcomb ing
    where allcomb ing = allcomb' ing 0
          allcomb' [] tot = if tot == total then [[0,0,0,0,0]] else []
          allcomb' (i:is) tot = concat [map (\x -> map (\(a,b)->am*a+b) $ zip i x) $ allcomb' is (tot+am)
                                        | am <- [0..(total-tot)]]
          computescore x = (product $ map (\x -> if x < 0 then 0 else x) $ init x,last x)
          cal500 (_,cal) = cal == 500 -- make this function always True for part 1

day15 :: IO ()
day15 = do
    input <- liftM (map (parse . words) . lines) $ readFile "day15.txt"
    --let input = [[-1,-2,6,3],[2,3,-2,-1]]
    print input
    let result = maximum $ getall input
    print result

main = day15