module PtrPoker.Poke where

import qualified PtrPoker.Compat.ByteString as ByteStringCompat
import qualified PtrPoker.Compat.Text as TextCompat
import qualified PtrPoker.Ffi as Ffi
import qualified PtrPoker.IO.Prim as PrimIO
import PtrPoker.Prelude hiding (concat)

{-# RULES
"foldMap" forall f foldable.
  foldMap f foldable =
    Poke $ \p -> foldM (\p (Poke poker) -> poker p) p foldable
  #-}

-- |
-- Abstraction over an IO action,
-- which takes a pointer, populates it and
-- produces a pointer right after the populated data.
newtype Poke = Poke {pokePtr :: Ptr Word8 -> IO (Ptr Word8)}

instance Semigroup Poke where
  {-# INLINE [1] (<>) #-}
  Poke lIO <> Poke rIO =
    Poke (\p -> lIO p >>= rIO)
  sconcat =
    concat

instance Monoid Poke where
  {-# INLINE [1] mempty #-}
  mempty =
    Poke return
  mconcat =
    concat

-- |
-- Reuses the IsString instance of 'ByteString'.
instance IsString Poke where
  fromString = byteString . fromString

-- |
-- Concatenate a foldable of pokes.
{-# INLINE [1] concat #-}
concat :: (Foldable f) => f Poke -> Poke
concat pokers =
  Poke (\p -> foldM (\p (Poke io) -> io p) p pokers)

-- |
-- Efficiently copy the contents of ByteString using @memcpy@.
{-# INLINE byteString #-}
byteString :: ByteString -> Poke
byteString bs =
  Poke $ inline ByteStringCompat.poke bs

-- |
-- Encode Word8 as byte, incrementing the pointer by 1.
{-# INLINE [1] word8 #-}
word8 :: Word8 -> Poke
word8 a =
  Poke (\p -> PrimIO.pokeWord8 p a $> plusPtr p 1)

-- |
-- Encode Word16 in Little-endian.
{-# INLINE [1] lWord16 #-}
lWord16 :: Word16 -> Poke
lWord16 a =
  Poke (\p -> PrimIO.pokeLEWord16 p a $> plusPtr p 2)

-- |
-- Encode Word16 in Big-endian.
{-# INLINE [1] bWord16 #-}
bWord16 :: Word16 -> Poke
bWord16 a =
  Poke (\p -> PrimIO.pokeBEWord16 p a $> plusPtr p 2)

-- |
-- Encode Word32 in Little-endian.
{-# INLINE [1] lWord32 #-}
lWord32 :: Word32 -> Poke
lWord32 a =
  Poke (\p -> PrimIO.pokeLEWord32 p a $> plusPtr p 4)

-- |
-- Encode Word32 in Big-endian.
{-# INLINE [1] bWord32 #-}
bWord32 :: Word32 -> Poke
bWord32 a =
  Poke (\p -> PrimIO.pokeBEWord32 p a $> plusPtr p 4)

-- |
-- Encode Word64 in Little-endian.
{-# INLINE [1] lWord64 #-}
lWord64 :: Word64 -> Poke
lWord64 a =
  Poke (\p -> PrimIO.pokeLEWord64 p a $> plusPtr p 8)

-- |
-- Encode Word64 in Big-endian.
{-# INLINE [1] bWord64 #-}
bWord64 :: Word64 -> Poke
bWord64 a =
  Poke (\p -> PrimIO.pokeBEWord64 p a $> plusPtr p 8)

-- |
-- Encode Int16 in Little-endian.
{-# INLINE lInt16 #-}
lInt16 :: Int16 -> Poke
lInt16 = lWord16 . fromIntegral

-- |
-- Encode Int16 in Big-endian.
{-# INLINE bInt16 #-}
bInt16 :: Int16 -> Poke
bInt16 = bWord16 . fromIntegral

-- |
-- Encode Int32 in Little-endian.
{-# INLINE lInt32 #-}
lInt32 :: Int32 -> Poke
lInt32 = lWord32 . fromIntegral

-- |
-- Encode Int32 in Big-endian.
{-# INLINE bInt32 #-}
bInt32 :: Int32 -> Poke
bInt32 = bWord32 . fromIntegral

-- |
-- Encode Int64 in Little-endian.
{-# INLINE lInt64 #-}
lInt64 :: Int64 -> Poke
lInt64 = lWord64 . fromIntegral

-- |
-- Encode Int64 in Big-endian.
{-# INLINE bInt64 #-}
bInt64 :: Int64 -> Poke
bInt64 = bWord64 . fromIntegral

-- |
-- Encode Text in UTF8.
{-# INLINE textUtf8 #-}
textUtf8 :: Text -> Poke
textUtf8 = Poke . TextCompat.pokeInUtf8

-- * ASCII integers

-------------------------

-- |
-- Encode Int8 as a signed ASCII decimal.
{-# INLINE [1] int8AsciiDec #-}
int8AsciiDec :: Int8 -> Poke
int8AsciiDec a =
  Poke (Ffi.pokeIntInDec (fromIntegral a))

-- |
-- Encode Int16 as a signed ASCII decimal.
{-# INLINE [1] int16AsciiDec #-}
int16AsciiDec :: Int16 -> Poke
int16AsciiDec a =
  Poke (Ffi.pokeIntInDec (fromIntegral a))

-- |
-- Encode Int32 as a signed ASCII decimal.
{-# INLINE [1] int32AsciiDec #-}
int32AsciiDec :: Int32 -> Poke
int32AsciiDec a =
  Poke (Ffi.pokeIntInDec (fromIntegral a))

-- |
-- Encode Int64 as a signed ASCII decimal.
{-# INLINE [1] int64AsciiDec #-}
int64AsciiDec :: Int64 -> Poke
int64AsciiDec a =
  Poke (Ffi.pokeLongLongIntInDec (fromIntegral a))

-- |
-- Encode Int as a signed ASCII decimal.
{-# INLINE [1] intAsciiDec #-}
intAsciiDec :: Int -> Poke
intAsciiDec a =
  Poke (Ffi.pokeLongLongIntInDec (fromIntegral a))

-- |
-- Encode Word8 as an unsigned ASCII decimal.
{-# INLINE [1] word8AsciiDec #-}
word8AsciiDec :: Word8 -> Poke
word8AsciiDec a =
  Poke (Ffi.pokeUIntInDec (fromIntegral a))

-- |
-- Encode Word16 as an unsigned ASCII decimal.
{-# INLINE [1] word16AsciiDec #-}
word16AsciiDec :: Word16 -> Poke
word16AsciiDec a =
  Poke (Ffi.pokeUIntInDec (fromIntegral a))

-- |
-- Encode Word32 as an unsigned ASCII decimal.
{-# INLINE [1] word32AsciiDec #-}
word32AsciiDec :: Word32 -> Poke
word32AsciiDec a =
  Poke (Ffi.pokeUIntInDec (fromIntegral a))

-- |
-- Encode Word64 as an unsigned ASCII decimal.
{-# INLINE [1] word64AsciiDec #-}
word64AsciiDec :: Word64 -> Poke
word64AsciiDec a =
  Poke (Ffi.pokeLongLongUIntInDec (fromIntegral a))

-- |
-- Encode Word as an unsigned ASCII decimal.
{-# INLINE [1] wordAsciiDec #-}
wordAsciiDec :: Word -> Poke
wordAsciiDec a =
  Poke (Ffi.pokeLongLongUIntInDec (fromIntegral a))

-- |
-- Encode Double as a signed ASCII decimal.
{-# INLINE doubleAsciiDec #-}
doubleAsciiDec :: Double -> Poke
doubleAsciiDec a =
  Poke $ \ptr ->
    Ffi.pokeDouble a ptr
      & fmap (plusPtr ptr . fromIntegral)

-- * Low level

-------------------------

-- |
-- Having the amount of bytes to be written precomputed,
-- executes an action,
-- which fills the pointer going downward,
-- starting from the pointer that follows the chunk.
-- I.e., you have to decrement the pointer
-- before writing the first byte,
-- decrement it again before writing the second byte and so on.
{-# INLINE sizedReverse #-}
sizedReverse :: Int -> (Ptr Word8 -> IO a) -> Poke
sizedReverse size action =
  Poke $ \ptr ->
    let afterPtr =
          plusPtr ptr size
     in action afterPtr $> afterPtr