module Sound.EsounD.Internals
    ( Frame(..)

    , Channels(..)
    , Mono
    , Stereo

    , wrapSocket
    , closeSocket
    , withCStrOrNull
    )
    where

import Bindings.EsounD
import Data.Int
import Foreign.C.String
import Foreign.C.Types
import Foreign.Ptr
import System.IO
import System.Posix.IO
import System.Posix.Types

class Frame fr where
    frameFmt ∷ fr → C'esd_format_t

instance Frame Int8 where
    frameFmt _ = c'ESD_BITS8

instance Frame Int16 where
    frameFmt _ = c'ESD_BITS16

class Channels ch where
    channelFmt ∷ ch → C'esd_format_t

data Mono
instance Channels Mono where
    channelFmt _ = c'ESD_MONO

data Stereo
instance Channels Stereo where
    channelFmt _ = c'ESD_STEREO


wrapSocket :: String -> CInt → IO Handle
wrapSocket e (-1) = fail e
wrapSocket _ fd   = fdToHandle (Fd fd)

closeSocket :: Handle → IO ()
closeSocket h = do (Fd fd) ← handleToFd h
                   _       ← c'esd_close (fromIntegral fd)
                   return ()

withCStrOrNull :: Maybe String → (CString → IO a) → IO a
withCStrOrNull Nothing  f = f nullPtr
withCStrOrNull (Just s) f = withCString s f