import System.Random (StdGen, mkStdGen, randomR)

type Point = (Float, Float)

transformation1 :: Point -> Point
transformation1 (_, y) = (0, 0.16 * y)

transformation2 :: Point -> Point
transformation2 (x, y) = (0.85 * x + 0.04 * y, -0.04 * x + 0.85 * y + 1.6)

transformation3 :: Point -> Point
transformation3 (x, y) = (0.2 * x - 0.26 * y, 0.23 * x + 0.22 * y + 1.6)

transformation4 :: Point -> Point
transformation4 (x, y) = (-0.15 * x + 0.28 * y, 0.26 * x + 0.24 * y + 0.44)

applyTransformation :: Point -> Float -> Point
applyTransformation point random
  | random < 0.01 = transformation1 point
  | random < 0.86 = transformation2 point
  | random < 0.93 = transformation3 point
  | otherwise = transformation4 point

genNextPoint :: StdGen -> Point -> (Point, StdGen)
genNextPoint gen point =
  let (random, newGen) = randomR (0.0, 1.0 :: Float) gen
  in (applyTransformation point random, newGen)

barnsleyFern :: StdGen -> Point -> Int -> [Point]
barnsleyFern _ _ 0 = []
barnsleyFern gen startPoint n =
  let (nextPoint, newGen) = genNextPoint gen startPoint
  in startPoint : barnsleyFern newGen nextPoint (n - 1)


n = 1000
randomSeed = 17

main :: IO ()
main = print $ barnsleyFern (mkStdGen randomSeed) (0, 0) n