{-# LANGUAGE FlexibleContexts, UndecidableInstances, TypeFamilies, TypeOperators, TemplateHaskell, NPlusKPatterns #-}

module Data.TrieMap.Rep.Instances()  where

import Data.TrieMap.Rep
import Data.TrieMap.Rep.TH
import Data.TrieMap.Regular.Base
-- import Data.TrieMap.OrdMap
import Data.TrieMap.Modifiers
-- import Language.Haskell.TH

import Control.Arrow

import Data.Char
import Data.Int
import Data.Word
import Data.Foldable (toList)
import Data.Bits
import Data.Array.IArray
import qualified Data.IntSet as ISet
import qualified Data.IntMap as IMap
import Data.ByteString hiding (map)
import qualified Data.ByteString as BS

import Data.Sequence (Seq, (|>))
import qualified Data.Sequence as Seq
import qualified Data.Foldable as Fold

import qualified Data.Map as Map
import qualified Data.Set as Set

import Prelude hiding (concat, take, length)

type Pair a = (,) a
type Sum a = Either a

type instance RepT Rev = Rev
type instance Rep (Rev a) = Rev (Rep a)

$(genRepT [d|
   instance ReprT Rev where
	toRepTMap f (Rev a) = Rev (f a)
	fromRepTMap f (Rev a) = Rev (f a) |])

type instance RepT Maybe = Sum ()
type instance Rep (Maybe a) = RepT Maybe (Rep a)

$(genRepT [d|
   instance ReprT Maybe where
	toRepTMap f = maybe (Left ()) (Right . f)
	fromRepTMap f = either (const Nothing) (Just . f) |])

type instance RepT [] = []
type instance Rep [a] = [Rep a]

$(genRepT [d| 
   instance ReprT [] where
	toRepTMap = map
	fromRepTMap = map |])

type instance RepT ((,) a) = Pair (Rep a)
type instance Rep (a, b) = RepT ((,) a) (Rep b)

$(genRepT [d|
    instance Repr a => ReprT ((,) a) where
	toRepTMap f = toRep *** f
	fromRepTMap f = fromRep *** f |])

-- instance (ReprT ((,) a), Repr b) => Repr ((,) a b) where

-- instance (Repr a, Repr b) => Repr (a, b) where
-- 	toRep = fmap toRep . toRepT
-- 	fromRep = fromRepT . fmap fromRep

type instance RepT ((,,) a b) = K0 (Rep a) :*: K0 (Rep b) :*: I0
type instance Rep (a, b, c) = RepT ((,,) a b) (Rep c)

$(genRepT [d|
   instance (Repr a, Repr b) => ReprT ((,,) a b) where
	toRepTMap f (a, b, c) = K0 (toRep a) :*: K0 (toRep b) :*: I0 (f c)
	fromRepTMap f (K0 a :*: K0 b :*: I0 c) = (fromRep a, fromRep b, f c) |])

type instance RepT ((,,,) a b c) = K0 (Rep a) :*: K0 (Rep b) :*: K0 (Rep c) :*: I0
type instance Rep (a, b, c, d) = RepT ((,,,) a b c) (Rep d)

$(genRepT [d|
   instance (Repr a, Repr b, Repr c) => ReprT ((,,,) a b c) where
	toRepTMap f (a, b, c, d) = K0 (toRep a) :*: K0 (toRep b) :*: K0 (toRep c) :*: I0 (f d)
	fromRepTMap f (K0 a :*: K0 b :*: K0 c :*: I0 d) = (fromRep a, fromRep b, fromRep c, f d) |])

type instance RepT (Either a) = Sum (Rep a)
type instance Rep (Either a b) = RepT (Either a) (Rep b)

$(genRepT [d|
  instance Repr a => ReprT (Either a) where
	toRepTMap f = either (Left . toRep) (Right . f)
	fromRepTMap f = either (Left . fromRep) (Right . f) |])

type instance Rep Bool = Sum () ()
instance Repr Bool where
	toRep False = Left ()
	toRep True = Right ()
	fromRep = either (const False) (const True)

type instance Rep Char = Word32
instance Repr Char where
	toRep = fromIntegral . ord
	fromRep = chr . fromIntegral

type instance Rep () = ()
instance Repr () where
	toRep _ = ()
	fromRep _ = ()

type instance Rep Double = Ordered Double
instance Repr Double where
	toRep = Ord
	fromRep = unOrd

type instance Rep Int = Rep Int32
instance Repr Int where
	toRep = toSigned
	fromRep = fromSigned

type instance Rep Word8 = Word32
instance Repr Word8 where
	toRep = fromIntegral
	fromRep = fromIntegral

type instance Rep Word16 = Word32
instance Repr Word16 where
	toRep = fromIntegral
	fromRep = fromIntegral

type instance Rep Word = Word32
instance Repr Word where
	toRep = fromIntegral
	fromRep = fromIntegral

type instance Rep Int8 = Rep Int32

instance Repr Int8 where
	toRep = toSigned
	fromRep = fromSigned

type instance Rep Int16 = Rep Int32
instance Repr Int16 where
	toRep = toSigned
	fromRep = fromSigned

type instance Rep Int32 = Sum (Rev Word32) Word32
instance Repr Int32 where
	toRep = toSigned
	fromRep = fromSigned

type instance Rep Word64 = Pair Word32 Word32
instance Repr Word64 where
	toRep x = (fromIntegral (x `shiftR` 32), fromIntegral x)
	fromRep (x, y) = fromIntegral x `shiftL` 32 .|. fromIntegral y

type instance Rep Int64 = Sum (Rev (Rep Word64)) (Rep Word64)
instance Repr Int64 where
	toRep x | x < 0	= Left (Rev (toRep' (fromIntegral (-x))))
		| otherwise = Right (toRep' (fromIntegral x))
		where toRep' = toRep :: Word64 -> Rep Word64
	fromRep (Left (Rev x)) = - fromIntegral ((fromRep :: Rep Word64 -> Word64) x)
	fromRep (Right x) = fromIntegral ((fromRep :: Rep Word64 -> Word64) x)

{-# INLINE toSigned #-}
toSigned :: Integral a => a -> Sum (Rev Word32) Word32
toSigned x
	| x < 0		= Left (Rev (fromIntegral (-x)))
	| otherwise	= Right (fromIntegral x)

{-# INLINE fromSigned #-}
fromSigned :: Integral a => Sum (Rev Word32) Word32 -> a
fromSigned = either (\ (Rev x) -> - fromIntegral x) fromIntegral

type instance Rep Word32 = Word32
instance Repr Word32 where
	toRep = id
	fromRep = id

type instance Rep ByteString = ([] :*: I0) Word32
instance Repr ByteString where
	toRep xs = toList64 xs :*: I0 (fromIntegral (length xs))
	fromRep (xs :*: I0 n) = case xs of
		[]	-> BS.empty
		(x:xs) -> fst (unfoldrN (fromIntegral n) toBlock (W (Words 3 x) xs))

data Words = Words {ix :: {-# UNPACK #-} !Int, word32 :: {-# UNPACK #-} !Word32}
data Words' = W {-# UNPACK #-} !Words [Word32]

toList64 :: ByteString -> [Word32]
toList64 xs = case BS.foldl c (Words 4 0, Seq.empty) xs of
	(Words i w32, ys) -> toList ys ++ [w32]
	where	fS :: Word8 -> Int -> Word32
		fS w x = fromIntegral w `shiftL` x
		(Words 0 w, xs) `c` w8
			= (Words 3 (w .|. sL w8 24), xs |> w)
		(Words i' w, xs) `c` w8
			= let !i = i' - 1 in (Words i (w .|. sL w8 (8 * i)), xs)
		sL :: Word8 -> Int -> Word32
		w `sL` x = fromIntegral w `shiftL` x

toBlock :: Words' -> Maybe (Word8, Words')
toBlock (W (Words i0@(i+1) w) xs) = Just (extract w (8 * i0), (W (Words i w) xs))
	where	extract :: Word32 -> Int -> Word8
		extract w x = fromIntegral (w `shiftR` x)
toBlock (W (Words 0 w) (x:xs)) = Just (fromIntegral w, (W (Words 3 x) xs))
toBlock _ = Nothing

type instance RepT (Array i) = L (Pair (Rep i)) :*: K0 (Pair (Rep i) (Rep i))
type instance Rep (Array i e) = RepT (Array i) (Rep e)

$(genRepT [d| 
   instance (Repr i, Ix i) => ReprT (Array i) where
	toRepTMap f arr = List [(toRep i, f a) | (i, a) <- assocs arr] :*: K0 (toRep l, toRep u)
		where (l, u) = bounds arr
	fromRepTMap f (List xs :*: K0 (l, r))
		= array (fromRep l, fromRep r) [(fromRep k, f a) | (k, a) <- xs] |])

type instance RepT Set.Set = []
type instance RepT (Map.Map k) = L (Pair (Rep k))
type instance Rep (Set.Set a) = [Rep a]
type instance Rep (Map.Map k a) = RepT (Map.Map k) (Rep a)

$(genRepT [d|
   instance ReprT Set.Set where
	toRepTMap f s = Fold.foldr ((:) . f) [] s
	fromRepTMap f xs = Set.fromDistinctAscList [f x | x <- xs] |])

$(genRepT [d|
   instance Repr k => ReprT (Map.Map k) where
	toRepTMap f m = List (Map.foldWithKey (\ k a xs -> (toRep k, f a):xs) [] m)
	fromRepTMap f (List xs) = Map.fromDistinctAscList [(fromRep k, f x) | (k, x) <- xs] |])

type instance RepT Rev = Rev
type instance Rep (Rev a) = Rev (Rep a)

-- -- $(genRepT [d|
--    instance ReprT Rev where
--    	toRepTMap f (Rev m) = Rev (f m)
-- 	fromRepTMap f (Rev m) = Rev (f m) |])

type instance Rep ISet.IntSet = Rep [Int]
type instance RepT IMap.IntMap = L (Pair (Rep Int))
type instance Rep (IMap.IntMap a) = RepT IMap.IntMap (Rep a)

instance Repr ISet.IntSet where
	toRep = toRep . ISet.toList
	fromRep = ISet.fromDistinctAscList . fromRep


type instance RepT Seq.Seq = []
type instance Rep (Seq.Seq a) = [Rep a]

-- type instance Rep (Rev a) = Rev (Rep a)

$(genRepT [d|
   instance ReprT Seq.Seq where
	toRepTMap f = Fold.foldr (\ a xs -> f a:xs) []
	fromRepTMap f = Fold.foldl (\ xs a -> xs |> f a) Seq.empty |])


-- instance Functor Rev where
-- 	fmap f (Rev a) = Rev (f a)