{-# LANGUAGE CPP                      #-}
{-# LANGUAGE ForeignFunctionInterface #-}

module Foreign.CUDA.FFT.Plan (

  -- * Context
  Handle(..),
  Type(..),
  plan1D,
  plan2D,
  plan3D,
  destroy,

) where

-- Friends
import Foreign.CUDA.FFT.Error
import Foreign.CUDA.FFT.Internal.C2HS

-- System
import Foreign
import Foreign.C
import Control.Monad                            ( liftM )

#include <cufft.h>
{# context lib="cufft" #}


-- | Operations handle
--
newtype Handle = Handle { useHandle :: {# type cufftHandle #}}

{# enum cufftType as Type
  {}
  with prefix="CUFFT" deriving (Eq, Show) #}

-- Context management ----------------------------------------------------------
--

-- | Creates a 1D FFT plan configuration for a specified signal size and data type.
-- The third argument tells CUFFT how many 1D transforms to configure.
--
plan1D :: Int -> Type -> Int -> IO Handle
plan1D nx t batch = resultIfOk =<< cufftPlan1d nx t batch

{# fun unsafe cufftPlan1d
  { alloca-   `Handle' peekHdl*
  ,           `Int'
  , cFromEnum `Type'
  ,           `Int'             } -> `Result' cToEnum #}
  where
    peekHdl = liftM Handle . peek

-- | Creates a 2D FFT plan configuration for a specified signal size and data type.
--
plan2D :: Int -> Int -> Type -> IO Handle
plan2D nx ny t = resultIfOk =<< cufftPlan2d nx ny t

{# fun unsafe cufftPlan2d
  { alloca-   `Handle' peekHdl*
  ,           `Int'
  ,           `Int'
  , cFromEnum `Type'            } -> `Result' cToEnum #}
  where
    peekHdl = liftM Handle . peek

-- | Creates a 3D FFT plan configuration for a specified signal size and data type.
--
plan3D :: Int -> Int -> Int -> Type -> IO Handle
plan3D nx ny nz t = resultIfOk =<< cufftPlan3d nx ny nz t

{# fun unsafe cufftPlan3d
  { alloca-   `Handle' peekHdl*
  ,           `Int'
  ,           `Int'
  ,           `Int'
  , cFromEnum `Type'            } -> `Result' cToEnum #}
  where
    peekHdl = liftM Handle . peek

-- | This function releases hardware resources used by the CUFFT plan. The
-- release of GPU resources may be deferred until the application exits. This
-- function is usually the last call with a particular handle to the CUFFT
-- plan.
--
destroy :: Handle -> IO ()
destroy ctx = nothingIfOk =<< cufftDestroy ctx

{# fun unsafe cufftDestroy
  { useHandle `Handle' } -> `Result' cToEnum #}