{-# LANGUAGE ParallelListComp #-}
import Linear.V3
import Linear.V4
import Control.Monad
import Data.List
import Control.Lens
import Data.Function

main :: IO ()
main = do
    input <- lines <$> readFile "input"
    print input
--    print $ toV3 input
--    print $ updateNeighbours $ toV3 input
    let final =  flip (!!) 6 $ iterate step $ toV3 input
    putStrLn $ visualize (-2) final
    putStrLn $ visualize (-1) final
    putStrLn $ visualize 0 final
    print $ length final

visualize :: Int -> [V3 Int] -> String
visualize z vs = unlines $ visualize' (filter ((==z) . (^._z)) vs) (replicate height (replicate width '.'))
    where x' = maximumBy (compare `on` (^._x)) vs
          y' = maximumBy (compare `on` (^._y)) vs
          x = minimumBy (compare `on` (^._x)) vs
          y = minimumBy (compare `on` (^._y)) vs
          width = (x'-x) ^._x +1
          height = (y'-y) ^._y +1
          visualize' [] arr = arr
          visualize' ((V3 x'' y'' _):vs_f) arr = visualize' vs_f (beg++newLine:end)
              where (beg,line:end) = splitAt (y''-(y^._y)) arr
                    (beg',_:end') = splitAt (x''-(x^._x)) line
                    newLine = beg' ++ '#' : end'



toV3 :: [String] -> [V3 Int]
toV3 input = [V3 x y 0 | (y,line)<-zip [0..] input, (x,c)<-zip [0..] line, c=='#']

step :: [V3 Int] -> [V3 Int]
step state = (nub . concatMap fst . filter f . ap zip (map length) . group . sort . updateNeighbours) state
    where f (x,n) = n==3 || n==2 && head x `elem` state

updateNeighbours :: [V3 Int] -> [V3 Int]
updateNeighbours = concatMap f where
    f coord = [coord + V3 x y z | [x,y,z]<-replicateM 3 [(-1)..1] \\ [[0,0,0]]]

mapI :: Num b => (a -> b -> c) -> [a] -> [c]
mapI f l = mapI' f 0 l where
    mapI' _ _ []     = []
    mapI' f n (x:xs) = f x n : mapI' f (n+1) xs