{-# LANGUAGE BlockArguments #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE PatternSynonyms #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE ViewPatterns #-}

-- | Specialized and inlined @V2 Word32@.

module Geomancy.UVec2
  ( UVec2
  , uvec2
  , withUVec2
  , pattern WithUVec2
  , convert
  , fromTuple
  , dot
  ) where

import Control.DeepSeq (NFData(rnf))
import Data.Coerce (Coercible, coerce)
import Data.MonoTraversable (Element, MonoFunctor(..), MonoPointed(..))
import Data.Word (Word32)
import Foreign (Storable(..))
import Foreign.Ptr.Diff (peekDiffOff, pokeDiffOff)
import GHC.Ix (Ix(..))

import Geomancy.Elementwise (Elementwise(..))
import Graphics.Gl.Block (Block(..))

data UVec2 = UVec2
  {-# UNPACK #-} !Word32
  {-# UNPACK #-} !Word32
  deriving (Eq, Ord, Show)

{-# INLINE uvec2 #-}
uvec2 :: Word32 -> Word32 -> UVec2
uvec2 = UVec2

{-# INLINE withUVec2 #-}
withUVec2
  :: UVec2
  -> (Word32 -> Word32 -> r)
  -> r
withUVec2 (UVec2 a b) f = f a b

pattern WithUVec2 :: Word32 -> Word32 -> UVec2
pattern WithUVec2 a b <- ((`withUVec2` (,)) -> (a, b))
{-# COMPLETE WithUVec2 #-}

{-# INLINE convert #-}
convert :: Coercible v UVec2 => (Word32 -> a) -> (a -> a -> r) -> v -> r
convert f t v =
  withUVec2 (coerce v) \a b ->
    t (f a) (f b)

{-# INLINE fromTuple #-}
fromTuple :: (Word32, Word32) -> UVec2
fromTuple (x, y) = uvec2 x y

instance NFData UVec2 where
  rnf UVec2{} = ()

type instance Element UVec2 = Word32

instance MonoFunctor UVec2 where
  {-# INLINE omap #-}
  omap f v =
    withUVec2 v \x y ->
      uvec2 (f x) (f y)

instance MonoPointed UVec2 where
  {-# INLINE opoint #-}
  opoint x = uvec2 x x

instance Elementwise UVec2 where
  {-# INLINE emap2 #-}
  emap2 f p0 p1 =
    withUVec2 p0 \x0 y0 ->
    withUVec2 p1 \x1 y1 ->
      uvec2
        (f x0 x1)
        (f y0 y1)

  {-# INLINE emap3 #-}
  emap3 f p0 p1 p2 =
    withUVec2 p0 \x0 y0 ->
    withUVec2 p1 \x1 y1 ->
    withUVec2 p2 \x2 y2 ->
      uvec2
        (f x0 x1 x2)
        (f y0 y1 y2)

  {-# INLINE emap4 #-}
  emap4 f p0 p1 p2 p3 =
    withUVec2 p0 \x0 y0 ->
    withUVec2 p1 \x1 y1 ->
    withUVec2 p2 \x2 y2 ->
    withUVec2 p3 \x3 y3 ->
      uvec2
        (f x0 x1 x2 x3)
        (f y0 y1 y2 y3)

  {-# INLINE emap5 #-}
  emap5 f p0 p1 p2 p3 p4 =
    withUVec2 p0 \x0 y0 ->
    withUVec2 p1 \x1 y1 ->
    withUVec2 p2 \x2 y2 ->
    withUVec2 p3 \x3 y3 ->
    withUVec2 p4 \x4 y4 ->
      uvec2
        (f x0 x1 x2 x3 x4)
        (f y0 y1 y2 y3 y4)

-- XXX: That's one nasty instance...
instance Num UVec2 where
  {-# INLINE (+) #-}
  UVec2 l1 l2 + UVec2 r1 r2 =
    UVec2
      (l1 + r1)
      (l2 + r2)

  {-# INLINE (-) #-}
  UVec2 l1 l2 - UVec2 r1 r2 =
    UVec2
      (l1 - r1)
      (l2 - r2)

  {-# INLINE (*) #-}
  UVec2 l1 l2 * UVec2 r1 r2 =
    UVec2
      (l1 * r1)
      (l2 * r2)

  {-# INLINE abs #-}
  abs (UVec2 a b) =
    UVec2 (abs a) (abs b)

  {-# INLINE signum #-}
  signum v2 = withUVec2 v2 \a b ->
    uvec2 (signum a) (signum b)

  {-# INLINE fromInteger #-}
  fromInteger x = UVec2 x' x'
    where
      x' = fromInteger x

{-# INLINE dot #-}
dot :: UVec2 -> UVec2 -> Word32
dot (UVec2 l1 l2) (UVec2 r1 r2) =
  l1 * r1 + l2 * r2

instance Storable UVec2 where
  {-# INLINE sizeOf #-}
  sizeOf _ = 8

  {-# INLINE alignment #-}
  alignment _ = 8

  {-# INLINE poke #-}
  poke ptr v4 =
    withUVec2 v4 \a b -> do
      pokeByteOff ptr 0 a
      pokeByteOff ptr 4 b

  {-# INLINE peek #-}
  peek ptr = uvec2
    <$> peekByteOff ptr 0
    <*> peekByteOff ptr 4

instance Block UVec2 where
  type PackedSize UVec2 = 8
  alignment140 _  = 8
  sizeOf140 _     = 8
  alignment430    = alignment140
  sizeOf430       = sizeOf140
  isStruct _      = False
  read140     = peekDiffOff
  write140    = pokeDiffOff
  read430     = read140
  write430    = write140
  readPacked  = read140
  writePacked = write140
  {-# INLINE alignment140 #-}
  {-# INLINE sizeOf140 #-}
  {-# INLINE alignment430 #-}
  {-# INLINE sizeOf430 #-}
  {-# INLINE isStruct #-}
  {-# INLINE read140 #-}
  {-# INLINE write140 #-}
  {-# INLINE read430 #-}
  {-# INLINE write430 #-}
  {-# INLINE readPacked #-}
  {-# INLINE writePacked #-}

instance Ix UVec2 where
  {-# INLINE range #-}
  range (l, u) =
    withUVec2 l \l1 l2 ->
      withUVec2 u \u1 u2 ->
        uvec2
          <$> range (l1, u1)
          <*> range (l2, u2)

  {-# INLINE unsafeIndex #-}
  unsafeIndex (l, u) i =
    withUVec2 l \l1 l2 ->
      withUVec2 u \u1 u2 ->
        withUVec2 i \i1 i2 ->
          unsafeIndex (l2, u2) i2 + unsafeRangeSize (l2, u2) *
          unsafeIndex (l1, u1) i1

  {-# INLINE inRange #-}
  inRange (l, u) i =
    withUVec2 l \l1 l2 ->
      withUVec2 u \u1 u2 ->
        withUVec2 i \i1 i2 ->
          inRange (l1, u1) i1 &&
          inRange (l2, u2) i2