{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE FlexibleInstances #-}
module Synthesizer.ChunkySize.Signal where

import qualified Synthesizer.ChunkySize.Cut as Cut
import qualified Synthesizer.ChunkySize as ChunkySize

-- import qualified Synthesizer.Generic.Cut as CutG
import qualified Synthesizer.Generic.Signal as SigG

-- import qualified Synthesizer.Plain.Signal as Sig
import qualified Synthesizer.State.Signal as SigS
-- import qualified Synthesizer.Storable.Signal as SigSt
import qualified Data.StorableVector.Lazy.Pattern as SigStV
import qualified Data.StorableVector.Lazy as Vector

import Foreign.Storable (Storable)

import qualified Data.List.Match as Match

import Control.Monad.Trans.State (runStateT, )

import qualified Data.List as List

-- import NumericPrelude.Numeric
import Prelude
   (Maybe(Just), fst, (.), id, )


class (SigG.Write sig y, Cut.Transform (sig y)) => Write sig y where
   unfoldRN :: ChunkySize.T -> (s -> Maybe (y,s)) -> s -> sig y


instance Storable y => Write Vector.Vector y where
   {-# INLINE unfoldRN #-}
   unfoldRN size f =
      fst .
      SigStV.unfoldrN
         (ChunkySize.toStorableVectorSize size) f

instance Write [] y where
   {-# INLINE unfoldRN #-}
   unfoldRN size f =
      Match.take (ChunkySize.toNullList size) .
      List.unfoldr f

instance Write SigS.T y where
   {-# INLINE unfoldRN #-}
   unfoldRN size f =
      Cut.take size . SigS.unfoldR f


{-# INLINE replicate #-}
replicate :: (Write sig y) =>
   ChunkySize.T -> y -> sig y
replicate = iterateN id

{-# INLINE iterateN #-}
iterateN :: (Write sig y) =>
   (y -> y) -> ChunkySize.T -> y -> sig y
iterateN f size =
   unfoldRN size (\y -> Just (y, f y))

{-# INLINE fromState #-}
fromState :: (Write sig y) =>
   ChunkySize.T -> SigS.T y -> sig y
fromState size (SigS.Cons f x) =
   unfoldRN size (runStateT f) x