import Euterpea

import System.Random
import Data.Map hiding (map,foldr,foldl)

fisherYatesStep :: RandomGen g => (Map Int a, g) -> (Int, a) -> (Map Int a, g)
fisherYatesStep (m, gen) (i, x) = ((insert j x . insert i (m ! j)) m, gen')
  where
    (j, gen') = randomR (0, i) gen

fisherYates :: RandomGen g => g -> [a] -> ([a], g)
fisherYates gen [] = ([], gen)
fisherYates gen l =
  toElems $ foldl fisherYatesStep (initial (head l) gen) (numerate (tail l))
  where
    toElems (x, y) = (elems x, y)
    numerate = zip [1..]
    initial x gen = (singleton 0 x, gen)

dMinor = d 4 wn :=: f 4 wn :=: a 4 wn
gMajor = g 4 wn :=: b 4 wn :=: d 5 wn
cMajor = c 4 bn :=: e 4 bn :=: g 4 bn

t251 = dMinor :+: gMajor :+: cMajor

notes = [c,d,e,f,g,a,b]

l = map (\x -> x 4 hn) notes
m = foldr (:+:) (rest hn)  l

main = do g <- getStdGen
          let (sf,bla) = fisherYates g [60..71]
              nnotes = map (\x -> note en $ pitch x) sf
              msc = foldr (:+:) (rest hn) nnotes
          playDev 2 $ msc
          playDev 2 $ msc
          print msc

--main = playDev 2 $ c 4 wn
--main = playDev 2 $ t251

--main = playDev 2 m