{-# LANGUAGE DataKinds             #-}
{-# LANGUAGE DeriveDataTypeable    #-}
{-# LANGUAGE FlexibleContexts      #-}
{-# LANGUAGE FlexibleInstances     #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE ScopedTypeVariables   #-}
{-# LANGUAGE StandaloneDeriving    #-}
{-# LANGUAGE TypeFamilies          #-}
{-# LANGUAGE UndecidableInstances  #-}
-- |
-- Unboxed vectors with fixed length. Vectors from
-- "Data.Vector.Fixed.Unboxed" provide more flexibility at no
-- performeance cost.
module Data.Vector.Fixed.Primitive (
    -- * Immutable
    Vec
  , Vec1
  , Vec2
  , Vec3
  , Vec4
  , Vec5
    -- * Mutable
  , MVec
    -- * Type classes
  , Prim
  ) where

import Control.Monad
import Control.DeepSeq (NFData(..))
import Data.Data
import Data.Monoid              (Monoid(..))
import Data.Semigroup           (Semigroup(..))
import Data.Primitive.ByteArray
import Data.Primitive
import qualified Foreign.Storable as Foreign (Storable(..))
import GHC.TypeLits
import Prelude (Show(..),Eq(..),Ord(..),Num(..))
import Prelude ((++),($),($!),undefined,seq)


import Data.Vector.Fixed hiding (index)
import Data.Vector.Fixed.Mutable
import qualified Data.Vector.Fixed.Cont as C



----------------------------------------------------------------
-- Data type
----------------------------------------------------------------

-- | Unboxed vector with fixed length
newtype Vec (n :: Nat) a = Vec ByteArray

-- | Mutable unboxed vector with fixed length
newtype MVec (n :: Nat) s a = MVec (MutableByteArray s)

deriving instance Typeable Vec
deriving instance Typeable MVec

type Vec1 = Vec 1
type Vec2 = Vec 2
type Vec3 = Vec 3
type Vec4 = Vec 4
type Vec5 = Vec 5



----------------------------------------------------------------
-- Instances
----------------------------------------------------------------

instance (Arity n, Prim a, Show a) => Show (Vec n a) where
  show v = "fromList " ++ show (toList v)

instance (Arity n, Prim a, NFData a) => NFData (Vec n a) where
  rnf = foldl (\r a -> r `seq` rnf a) ()
  {-# INLINE rnf #-}

type instance Mutable (Vec n) = MVec n

instance (Arity n, Prim a) => MVector (MVec n) a where
  new = do
    v <- newByteArray $! arity (Proxy :: Proxy n)
                       * sizeOf (undefined :: a)
    return $ MVec v
  {-# INLINE new         #-}
  copy                       = move
  {-# INLINE copy        #-}
  move (MVec dst) (MVec src) = copyMutableByteArray dst 0 src 0 (arity (Proxy :: Proxy n))
  {-# INLINE move        #-}
  unsafeRead  (MVec v) i   = readByteArray  v i
  {-# INLINE unsafeRead  #-}
  unsafeWrite (MVec v) i x = writeByteArray v i x
  {-# INLINE unsafeWrite #-}

instance (Arity n, Prim a) => IVector (Vec n) a where
  unsafeFreeze (MVec v)   = do { a <- unsafeFreezeByteArray v; return $! Vec  a }
  unsafeThaw   (Vec  v)   = do { a <- unsafeThawByteArray   v; return $! MVec a }
  unsafeIndex  (Vec  v) i = indexByteArray v i
  {-# INLINE unsafeFreeze #-}
  {-# INLINE unsafeThaw   #-}
  {-# INLINE unsafeIndex  #-}



type instance Dim  (Vec  n) = n
type instance DimM (MVec n) = n

instance (Arity n, Prim a) => Vector (Vec n) a where
  construct  = constructVec
  inspect    = inspectVec
  basicIndex = index
  {-# INLINE construct  #-}
  {-# INLINE inspect    #-}
  {-# INLINE basicIndex #-}
instance (Arity n, Prim a) => VectorN Vec n a

instance (Arity n, Prim a, Eq a) => Eq (Vec n a) where
  (==) = eq
  {-# INLINE (==) #-}
instance (Arity n, Prim a, Ord a) => Ord (Vec n a) where
  compare = ord
  {-# INLINE compare #-}

instance (Arity n, Prim a, Monoid a) => Monoid (Vec n a) where
  mempty  = replicate mempty
  mappend = zipWith mappend
  {-# INLINE mempty  #-}
  {-# INLINE mappend #-}

instance (Arity n, Prim a, Semigroup a) => Semigroup (Vec n a) where
  (<>) = zipWith (<>)
  {-# INLINE (<>) #-}


instance (Typeable n, Arity n, Prim a, Data a) => Data (Vec n a) where
  gfoldl       = C.gfoldl
  gunfold      = C.gunfold
  toConstr   _ = con_Vec
  dataTypeOf _ = ty_Vec

ty_Vec :: DataType
ty_Vec  = mkDataType "Data.Vector.Fixed.Primitive.Vec" [con_Vec]

con_Vec :: Constr
con_Vec = mkConstr ty_Vec "Vec" [] Prefix

instance (Foreign.Storable a, Prim a, Arity n) => Foreign.Storable (Vec n a) where
  alignment = defaultAlignemnt
  sizeOf    = defaultSizeOf
  peek      = defaultPeek
  poke      = defaultPoke
  {-# INLINE alignment #-}
  {-# INLINE sizeOf    #-}
  {-# INLINE peek      #-}
  {-# INLINE poke      #-}