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

module Foreign.CUDA.FFT.Error
  where

-- System
import Data.Typeable
import Control.Exception

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


-- Error codes -----------------------------------------------------------------
--
{# enum cufftResult as Result
  { underscoreToCase }
  with prefix="CUFFT" deriving (Eq, Show) #}

-- Describe each error code
--
describe :: Result -> String
describe Success         = "success"
describe InvalidPlan     = "invalid plan handle"
describe AllocFailed     = "resource allocation failed"
describe InvalidType     = "no longer used"
describe InvalidValue    = "unsupported value or parameter passed to a function"
describe InternalError   = "internal error"
describe ExecFailed      = "failed to execute an FFT on the GPU"
describe SetupFailed     = "the CUFFT library failed to initialize"
describe InvalidSize     = "invalid transform size"
describe UnalignedData   = "no longer used"


-- Exceptions ------------------------------------------------------------------
--
data CUFFTException
  = ExitCode  Result
  | UserError String
  deriving Typeable

instance Exception CUFFTException

instance Show CUFFTException where
  showsPrec _ (ExitCode  s) = showString ("CUFFT Exception: " ++ describe s)
  showsPrec _ (UserError s) = showString ("CUFFT Exception: " ++ s)


-- | Raise a CUFFTException in the IO Monad
--
cufftError :: String -> IO a
cufftError s = throwIO (UserError s)


-- | Return the results of a function on successful execution, otherwise throw
-- an exception with an error string associated with the return code
--
resultIfOk :: (Result, a) -> IO a
resultIfOk (status,result) =
    case status of
        Success -> return  result
        _       -> throwIO (ExitCode status)


-- | Throw an exception with an error string associated with an unsuccessful
-- return code, otherwise return unit.
--
nothingIfOk :: Result -> IO ()
nothingIfOk status =
    case status of
        Success -> return  ()
        _       -> throwIO (ExitCode status)