import Data.Map as M
import Data.Maybe
import Numeric

learn :: [Bool] -> Map [Bool] Double -> Map [Bool] Double
learn hist brain = Prelude.foldr learn' brain [3..5]
  where learn' n = M.insertWithKey (const (+)) (take n hist) 1.0

guess :: Map [Bool] Double -> [Bool] -> Bool
guess brain hist = wAvg (Prelude.map guess' [2..4]) >= 0.5
  where wAvg xs = sum (Prelude.map (uncurry (*)) xs) / sum (Prelude.map snd xs)
        guess' n = (occ True / (occ True + occ False), occ True + occ False)
          where occ val = fromMaybe 0.0 $ M.lookup (val : take n hist) brain

play :: Int -> (Double, Double) -> [Bool] -> Map [Bool] Double -> IO a
play turn (wons, total) hist brain = do
  press <- getLine
  let key   = press == "f"
  let right = key == guess brain hist
  let wins  = (if right then succ else id) wons
  print $ "I guessed " ++ (if right then "RIGHT!" else "wrong.")
    ++ " My avg: " ++ showFFloat (Just 2) (wins / succ total) ""
  play (succ turn) (wins, succ total) (key:hist) (learn (key:hist) brain)

main = do
  print "aaronson oracle | Press 'f' or 'd' over and over (followed by enter)"
  print "                | and we'll try to predict which you'll press next."
  play 0 (0.0, 0.0) [] M.empty