module System.Socket.Internal.Platform where

import Control.Concurrent ( threadDelay )
import Control.Concurrent.MVar ( MVar, withMVar )
import Control.Exception ( throwIO )
import Control.Monad ( when )

import Data.Bits

import Foreign.Ptr
import Foreign.C.Types
import Foreign.C.String
import Foreign.Storable
import Foreign.Marshal

import System.Posix.Types ( Fd(..) )

import System.Socket.Internal.Message
import System.Socket.Internal.Exception

unsafeSocketWaitWrite :: Fd -> Int -> IO (IO ())
unsafeSocketWaitWrite _ iteration = do
  return (threadDelay $ 1 `shiftL` min iteration 20)

unsafeSocketWaitRead :: Fd -> Int -> IO (IO ())
unsafeSocketWaitRead  _ iteration = do
  return (threadDelay $ 1 `shiftL` min iteration 20)

unsafeSocketWaitConnected :: Fd -> IO ()
unsafeSocketWaitConnected fd =
  alloca $ \errPtr-> loop errPtr 0
  where
    loop errPtr iteration = do
        i <- c_connect_status fd errPtr
        when (i /= 0) $ case i of
          1  -> do
            -- Wait with exponential backoff.
            threadDelay $ 1 `shiftL` min iteration 20
            -- Try again.
            loop errPtr $! iteration + 1
          _  -> do
            SocketException <$> peek errPtr >>= throwIO

type CSSize
   = CInt

foreign import ccall unsafe "hs_socket"
  c_socket  :: CInt -> CInt -> CInt -> Ptr CInt -> IO Fd

foreign import ccall unsafe "hs_close"
  c_close   :: Fd -> Ptr CInt -> IO CInt

foreign import ccall unsafe "hs_bind"
  c_bind    :: Fd -> Ptr a -> CInt -> Ptr CInt -> IO CInt

foreign import ccall unsafe "hs_connect"
  c_connect :: Fd -> Ptr a -> CInt -> Ptr CInt -> IO CInt

foreign import ccall unsafe "hs_connect_status"
  c_connect_status :: Fd -> Ptr CInt -> IO CInt

foreign import ccall unsafe "hs_accept"
  c_accept  :: Fd -> Ptr a -> Ptr CInt -> Ptr CInt -> IO Fd

foreign import ccall unsafe "hs_listen"
  c_listen  :: Fd -> CInt -> Ptr CInt -> IO CInt

foreign import ccall unsafe "hs_send"
  c_send    :: Fd -> Ptr a -> CSize -> MessageFlags -> Ptr CInt -> IO CSSize

foreign import ccall unsafe "hs_sendto"
  c_sendto  :: Fd -> Ptr a -> CSize -> MessageFlags -> Ptr b -> CInt -> Ptr CInt -> IO CSSize

foreign import ccall unsafe "hs_recv"
  c_recv    :: Fd -> Ptr a -> CSize -> MessageFlags -> Ptr CInt -> IO CSSize

foreign import ccall unsafe "hs_recvfrom"
  c_recvfrom :: Fd -> Ptr a -> CSize -> MessageFlags -> Ptr b -> Ptr CInt -> Ptr CInt -> IO CSSize

foreign import ccall unsafe "hs_getsockopt"
  c_getsockopt  :: Fd -> CInt -> CInt -> Ptr a -> Ptr CInt -> Ptr CInt -> IO CInt

foreign import ccall unsafe "hs_setsockopt"
  c_setsockopt  :: Fd -> CInt -> CInt -> Ptr a -> CInt -> Ptr CInt -> IO CInt

foreign import ccall unsafe "memset"
  c_memset       :: Ptr a -> CInt -> CSize -> IO ()

foreign import ccall safe "hs_getaddrinfo"
  c_getaddrinfo  :: CString -> CString -> Ptr a -> Ptr (Ptr a) -> IO CInt

foreign import ccall unsafe "hs_freeaddrinfo"
  c_freeaddrinfo :: Ptr a -> IO ()

foreign import ccall safe "hs_getnameinfo"
  c_getnameinfo  :: Ptr a -> CInt -> CString -> CInt -> CString -> CInt -> CInt -> IO CInt

foreign import ccall unsafe "hs_gai_strerror"
  c_gai_strerror  :: CInt -> IO CString