module Part2 where

import Commons
import qualified Data.Map.Strict as M
import qualified Data.Set as S
import Data.Foldable (maximumBy)
import Data.Function (on)


getFutureFall' :: Snapshot -> S.Set Brick -> S.Set Brick
getFutureFall' s sFell =
  let falling = getFalling s
  in if null falling then sFell
     else let fell = getFell s falling
              newSFell = S.union (S.difference sFell (S.fromList $ map snd falling)) $ S.fromList $ map snd fell
          in getFutureFall' (getPostFall s falling fell) newSFell

getFutureFall :: Snapshot -> Brick -> S.Set Brick
getFutureFall s b = let newSnapshot = M.difference s $ M.fromList $ map (\ c -> ((z c, y c, x c), b)) b
                    in getFutureFall' newSnapshot S.empty

getReactions :: Snapshot -> [S.Set Brick]
getReactions s = S.toList $ S.fromList $ map (getFutureFall s) $ M.elems s