import Data.Char
import Data.List.Split

main :: IO ()
main = do
  input <- readFile "input"
--  let size = (11,7)
  let size = (101,103)
  let ls = map parseLine $ lines input
--  print $ part1 size ls
  part2 size ls

parseLine line = toPair $ map readPair $ words $ filter valid line
  where valid c = isDigit c || isSpace c || c == ',' || c == '-'

readPair s = toPair $ map readInt $ splitOn "," s

readInt :: String -> Int
readInt = read

toPair [a,b] = (a,b)

modp x y =
  let m = x `mod` y
  in if m < 0 then m+y else m

moveN n (mx,my) ((x,y), (vx,vy)) =
  (((x+n*vx) `modp` mx, (y+n*vy) `modp` my), (vx,vy))

part1 size robots = calcScore size (map (moveN 100 size) robots)

calcScore (sx, sy) robots =
  let (mx,my) = (sx `div` 2, sy `div` 2)
      positions = map fst robots
      q1 = filter (inBounds (0,0) (mx,my)) positions
      q2 = filter (inBounds (mx+1,0) (sx,my)) positions
      q3 = filter (inBounds (0,my+1) (mx,sy)) positions
      q4 = filter (inBounds (mx+1,my+1) (sx,sy)) positions
  in (length q1) * (length q2) * (length q3) * (length q4)

inBounds (minx,miny) (maxx,maxy) (x,y) =
  minx <= x && x < maxx &&
  miny <= y && y < maxy



part2 :: (Int,Int) -> [((Int,Int), (Int,Int))] -> IO ()
part2 size robots = doPart2 1000000000000000 0 size robots

doPart2 best gen size robots
  | gen > 10000 = return ()
  | otherwise = do
    let score = calcScore size robots
    if score < best then do
      putStrLn $ "gen " ++ (show gen)
      printGrid size (map fst robots)
      putStrLn ""
    else do return ()
    doPart2 (min score best) (gen+1) size (map (moveN 1 size) robots)

printGrid :: (Int,Int) -> [(Int,Int)] -> IO ()
printGrid (sx,sy) coords =
  let g = [[if (x,y) `elem` coords then '#' else '.' | x <- [0..sx-1]] | y <- [0..sy-1]]
  in mapM_ putStrLn g