    {-# LANGUAGE AllowAmbiguousTypes        #-}
    {-# LANGUAGE DataKinds                  #-}
    {-# LANGUAGE TypeOperators              #-}
    {-# LANGUAGE TypeApplications           #-}
    {-# LANGUAGE ScopedTypeVariables        #-}
    {-# LANGUAGE GeneralizedNewtypeDeriving #-}
    {-# LANGUAGE ConstraintKinds            #-}
    module Basement.Sized.UVect
        ( UVect
        , MUVect
        , unUVect
        , toUVect
        , empty
        , singleton
        , replicate
        , thaw
        , freeze
        , index
        , map
        , foldl'
        , foldr
        , cons
        , snoc
        , elem
        , sub
        , uncons
        , unsnoc
        , splitAt
        , all
        , any
        , find
        , reverse
        , sortBy
        , intersperse
        ) where

    import           Basement.Compat.Base
    import           Basement.Nat
    import           Basement.NormalForm
    import           Basement.Types.OffsetSize
    import           Basement.Monad
    import           Basement.PrimType (PrimType)
    import qualified Basement.UArray as A
    import qualified Basement.UArray.Mutable as A hiding (sub)
    import           Data.Proxy

    newtype UVect (n :: Nat) a = UVect { unUVect :: A.UArray a } deriving (NormalForm, Eq, Show)
    newtype MUVect (n :: Nat) ty st = MUVect { unMUVect :: A.MUArray ty st }

    toUVect :: forall n ty . (PrimType ty, KnownNat n, Countable ty n) => A.UArray ty -> Maybe (UVect n ty)
    toUVect b
        | expected == A.length b = Just (UVect b)
        | otherwise              = Nothing
      where
        expected = toCount @n

    empty :: PrimType ty => UVect 0 ty
    empty = UVect mempty

    singleton :: PrimType ty => ty -> UVect 1 ty
    singleton a = UVect (A.singleton a)

    create :: forall ty (n :: Nat) . (PrimType ty, Countable ty n, KnownNat n) => (Offset ty -> ty) -> UVect n ty
    create f = UVect $ A.create sz f
      where
        sz = natValCountOf (Proxy :: Proxy n)

    replicate :: forall n ty . (KnownNat n, Countable ty n, PrimType ty) => ty -> UVect n ty
    replicate a = UVect (A.replicate (toCount @n) a)

    thaw :: (KnownNat n, PrimMonad prim, PrimType ty) => UVect n ty -> prim (MUVect n ty (PrimState prim))
    thaw b = MUVect <$> A.thaw (unUVect b)

    freeze ::  (PrimMonad prim, PrimType ty, Countable ty n) => MUVect n ty (PrimState prim) -> prim (UVect n ty)
    freeze b = UVect <$> A.freeze (unMUVect b)

    write :: (PrimMonad prim, PrimType ty) => MUVect n ty (PrimState prim) -> Offset ty -> ty -> prim ()
    write (MUVect ma) ofs v = A.write ma ofs v

    read :: (PrimMonad prim, PrimType ty) => MUVect n ty (PrimState prim) -> Offset ty -> prim ty
    read (MUVect ma) ofs = A.read ma ofs

    indexStatic :: forall i n ty . (KnownNat i, CmpNat i n ~ 'LT, PrimType ty, Offsetable ty i) => UVect n ty -> ty
    indexStatic b = A.unsafeIndex (unUVect b) (toOffset @i)

    index :: forall i n ty . PrimType ty => UVect n ty -> Offset ty -> ty
    index b ofs = A.index (unUVect b) ofs

    map :: (PrimType a, PrimType b) => (a -> b) -> UVect n a -> UVect n b
    map f b = UVect (A.map f (unUVect b))

    foldl' :: PrimType ty => (a -> ty -> a) -> a -> UVect n ty -> a
    foldl' f acc b = A.foldl' f acc (unUVect b)

    foldr :: PrimType ty => (ty -> a -> a) -> a -> UVect n ty -> a
    foldr f acc b = A.foldr f acc (unUVect b)

    cons :: PrimType ty => ty -> UVect n ty -> UVect (n+1) ty
    cons e = UVect . A.cons e . unUVect

    snoc :: PrimType ty => UVect n ty -> ty -> UVect (n+1) ty
    snoc b = UVect . A.snoc (unUVect b)

    sub :: forall i j n ty
         . ( (i <=? n) ~ 'True
           , (j <=? n) ~ 'True
           , (i <=? j) ~ 'True
           , PrimType ty
           , KnownNat i
           , KnownNat j
           , Offsetable ty i
           , Offsetable ty j )
        => UVect n ty
        -> UVect (j-i) ty
    sub block = UVect (A.sub (unUVect block) (toOffset @i) (toOffset @j))

    uncons :: forall n ty . (CmpNat 0 n ~ 'LT, PrimType ty, KnownNat n, Offsetable ty n)
           => UVect n ty
           -> (ty, UVect (n-1) ty)
    uncons b = (indexStatic @0 b, UVect (A.sub (unUVect b) 1 (toOffset @n)))

    unsnoc :: forall n ty . (CmpNat 0 n ~ 'LT, KnownNat n, PrimType ty, Offsetable ty n)
           => UVect n ty
           -> (UVect (n-1) ty, ty)
    unsnoc b =
        ( UVect (A.sub (unUVect b) 0 (toOffset @n `offsetSub` 1))
        , A.unsafeIndex (unUVect b) (toOffset @n `offsetSub` 1))

    splitAt :: forall i n ty . (CmpNat i n ~ 'LT, PrimType ty, KnownNat i, Countable ty i) => UVect n ty -> (UVect i ty, UVect (n-i) ty)
    splitAt b =
        let (left, right) = A.splitAt (toCount @i) (unUVect b)
         in (UVect left, UVect right)

    elem :: PrimType ty => ty -> UVect n ty -> Bool
    elem e b = A.elem e (unUVect b)

    all :: PrimType ty => (ty -> Bool) -> UVect n ty -> Bool
    all p b = A.all p (unUVect b)

    any :: PrimType ty => (ty -> Bool) -> UVect n ty -> Bool
    any p b = A.any p (unUVect b)

    find :: PrimType ty => (ty -> Bool) -> UVect n ty -> Maybe ty
    find p b = A.find p (unUVect b)

    reverse :: PrimType ty => UVect n ty -> UVect n ty
    reverse = UVect . A.reverse . unUVect

    sortBy :: PrimType ty => (ty -> ty -> Ordering) -> UVect n ty -> UVect n ty
    sortBy f b = UVect (A.sortBy f (unUVect b))

    intersperse :: (CmpNat n 1 ~ 'GT, PrimType ty) => ty -> UVect n ty -> UVect (n+n-1) ty
    intersperse sep b = UVect (A.intersperse sep (unUVect b))

    toCount :: forall n ty . (KnownNat n, Countable ty n) => CountOf ty
    toCount = natValCountOf (Proxy @n)

    toOffset :: forall n ty . (KnownNat n, Offsetable ty n) => Offset ty
    toOffset = natValOffset (Proxy @n)