{-# LANGUAGE BangPatterns          #-}
{-# LANGUAGE FlexibleContexts      #-}
{-# LANGUAGE FlexibleInstances     #-}
{-# LANGUAGE MultiParamTypeClasses #-}
-- |
-- Module      : Data.Massiv.Array.Unsafe
-- Copyright   : (c) Alexey Kuleshevich 2018
-- License     : BSD3
-- Maintainer  : Alexey Kuleshevich <lehins@yandex.ru>
-- Stability   : experimental
-- Portability : non-portable
--
module Data.Massiv.Array.Unsafe
  ( -- * Creation
    unsafeMakeArray
  , unsafeGenerateArray
  , unsafeGenerateArrayP
  , unsafeGenerateM
  -- * Indexing
  , unsafeIndex
  , unsafeLinearIndex
  , unsafeLinearIndexM
  -- * Manipulations
  , unsafeBackpermute
  , unsafeTraverse
  , unsafeTraverse2
  , unsafeResize
  , unsafeExtract
  -- * Slicing
  , unsafeSlice
  , unsafeOuterSlice
  , unsafeInnerSlice
  -- * Mutable interface
  , unsafeThaw
  , unsafeFreeze
  , unsafeNew
  , unsafeNewZero
  , unsafeRead
  , unsafeLinearRead
  , unsafeWrite
  , unsafeLinearWrite
  ) where

import           Control.Monad.Primitive            (PrimMonad (..))
import           Control.Monad.ST                   (runST)
import           Data.Massiv.Array.Delayed.Internal (D)
import           Data.Massiv.Core.Common
import           Data.Massiv.Core.Scheduler
import           System.IO.Unsafe                   (unsafePerformIO)


unsafeBackpermute :: (Source r' ix' e, Index ix) =>
                     ix -> (ix -> ix') -> Array r' ix' e -> Array D ix e
unsafeBackpermute !sz ixF !arr =
  unsafeMakeArray (getComp arr) sz $ \ !ix -> unsafeIndex arr (ixF ix)
{-# INLINE unsafeBackpermute #-}


unsafeTraverse
  :: (Source r1 ix1 e1, Index ix)
  => ix
  -> ((ix1 -> e1) -> ix -> e)
  -> Array r1 ix1 e1
  -> Array D ix e
unsafeTraverse sz f arr1 =
  unsafeMakeArray (getComp arr1) sz (f (unsafeIndex arr1))
{-# INLINE unsafeTraverse #-}


unsafeTraverse2
  :: (Source r1 ix1 e1, Source r2 ix2 e2, Index ix)
  => ix
  -> ((ix1 -> e1) -> (ix2 -> e2) -> ix -> e)
  -> Array r1 ix1 e1
  -> Array r2 ix2 e2
  -> Array D ix e
unsafeTraverse2 sz f arr1 arr2 =
  unsafeMakeArray (getComp arr1) sz (f (unsafeIndex arr1) (unsafeIndex arr2))
{-# INLINE unsafeTraverse2 #-}


-- | Read an array element
unsafeRead :: (Mutable r ix e, PrimMonad m) =>
               MArray (PrimState m) r ix e -> ix -> m e
unsafeRead !marr !ix = unsafeLinearRead marr (toLinearIndex (msize marr) ix)
{-# INLINE unsafeRead #-}

-- | Write an element into array
unsafeWrite :: (Mutable r ix e, PrimMonad m) =>
               MArray (PrimState m) r ix e -> ix -> e -> m ()
unsafeWrite !marr !ix = unsafeLinearWrite marr (toLinearIndex (msize marr) ix)
{-# INLINE unsafeWrite #-}


-- | Create an array sequentially using mutable interface
unsafeGenerateArray :: Mutable r ix e => ix -> (ix -> e) -> Array r ix e
unsafeGenerateArray !sz f = runST $ do
  marr <- unsafeNew sz
  iterLinearM_ sz 0 (totalElem sz) 1 (<) $ \ !k !ix ->
    unsafeLinearWrite marr k (f ix)
  unsafeFreeze Seq marr
{-# INLINE unsafeGenerateArray #-}


-- | Create an array in parallel using mutable interface
--
-- @since 0.1.5
unsafeGenerateArrayP :: Mutable r ix e => [Int] -> ix -> (ix -> e) -> Array r ix e
unsafeGenerateArrayP wIds !sz f = unsafePerformIO $ do
  marr <- unsafeNew sz
  divideWork_ wIds sz $ \ !scheduler !chunkLength !totalLength !slackStart -> do
    loopM_ 0 (< slackStart) (+ chunkLength) $ \ !start ->
      scheduleWork scheduler $
        iterLinearM_ sz start (start + chunkLength) 1 (<) $ \ !k !ix ->
          unsafeLinearWrite marr k (f ix)
    scheduleWork scheduler $
      iterLinearM_ sz slackStart totalLength 1 (<) $ \ !k !ix ->
        unsafeLinearWrite marr k (f ix)
  unsafeFreeze (ParOn wIds) marr
{-# INLINE unsafeGenerateArrayP #-}