{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE PatternSynonyms    #-}

{-|
Module      : Std.IO.SockAddr
Description : TCP/UDP socket address API
Copyright   : (c) Winterland, 2018
License     : BSD
Maintainer  : drkoster@qq.com
Stability   : experimental
Portability : non-portable

This module provides necessary types and constant for low level socket operation.

-}

module Std.IO.SockAddr
  ( -- * name to address
    SockAddr(..)
  , sockAddrFamily
  , peekSockAddr
  , withSockAddr
   -- ** IPv4 address
  , InetAddr
  , inetAny
  , inetBroadcast
  , inetNone
  , inetLoopback
  , inetUnspecificGroup
  , inetAllHostsGroup
  , inetMaxLocalGroup
  , inetAddrToTuple
  , tupleToInetAddr
   -- ** IPv6 address
  , Inet6Addr
  , inet6Any
  , inet6Loopback
  , inet6AddrToTuple
  , tupleToInet6Addr
  , FlowInfo
  , ScopeID
  -- * port numbber
  , PortNumber 
  , aNY_PORT
  , htons
  , ntohs
  , ntohl
  , htonl
  -- * family, type, protocol
  , SocketFamily(..)
  , pattern AF_UNSPEC
  , pattern AF_INET
  , pattern AF_INET6
  , SocketType(..)
  , pattern SOCK_DGRAM
  , pattern SOCK_STREAM
  , pattern SOCK_SEQPACKET
  , pattern SOCK_RAW
  , pattern SOCK_RDM
  , SocketProtocol(..)
  , pattern IPPROTO_TCP
  , pattern IPPROTO_UDP
  ) where

import           Control.Monad.IO.Class
import           Control.Monad.Primitive
import           Data.Bits
import qualified Data.List                as List
import           Data.Primitive.PrimArray
import           Data.Ratio
import           Data.Typeable
import           Foreign
import           Foreign.C
import           GHC.ForeignPtr        (mallocPlainForeignPtrAlignedBytes)
import           GHC.Stack
import           Numeric               (showHex)
import           Std.Data.CBytes
import qualified Std.Data.Vector       as V
import           Std.Foreign.PrimArray
import           Std.IO.Exception
import           Std.IO.Resource
import           Std.IO.UV.Errno
import           System.IO.Unsafe      (unsafeDupablePerformIO)

#include "hs_uv.h" 

#if __GLASGOW_HASKELL__ < 800
#let alignment t = "%lu", (unsigned long)offsetof(struct {char x__; t (y__); }, y__)
#endif

#if defined(i386_HOST_ARCH) && defined(mingw32_HOST_OS)
#let CALLCONV = "stdcall"
#else
#let CALLCONV = "ccall"
#endif

--------------------------------------------------------------------------------

#if defined(_WIN32)
type CSaFamily = (#type unsigned short)
#elif defined(darwin_HOST_OS)
type CSaFamily = (#type u_char)
#else
type CSaFamily = (#type sa_family_t)
#endif

-- | IPv4 or IPv6 socket address, i.e. the `sockaddr_in` or `sockaddr_in6` struct.
-- 
data SockAddr 
    = SockAddrInet
        {-# UNPACK #-} !PortNumber  -- sin_port  (network byte order)
        {-# UNPACK #-} !InetAddr    -- sin_addr  (ditto)
    | SockAddrInet6
        {-# UNPACK #-} !PortNumber  -- sin6_port (network byte order)
        {-# UNPACK #-} !FlowInfo    -- sin6_flowinfo (ditto)
        {-# UNPACK #-} !Inet6Addr   -- sin6_addr (ditto)
        {-# UNPACK #-} !ScopeID     -- sin6_scope_id (ditto)
  deriving (Show, Eq, Ord)

sockAddrFamily :: SockAddr -> SocketFamily
sockAddrFamily (SockAddrInet _ _) = AF_INET
sockAddrFamily (SockAddrInet6 _ _ _ _) = AF_INET6

type FlowInfo = Word32
type ScopeID = Word32

--------------------------------------------------------------------------------

-- | Independent of endianness. For example @127.0.0.1@ is stored as @(127, 0, 0, 1)@.
--
-- For direct manipulation prefer 'inetAddrToTuple' and 'tupleToInetAddr'.
--
newtype InetAddr = InetAddr Word32 deriving (Eq, Ord)
instance Show InetAddr where
    showsPrec _ ia = 
        let (a,b,c,d) = inetAddrToTuple ia
        in ("InetAddr " ++) . shows a . ('.':)
                            . shows b . ('.':)
                            . shows c . ('.':)
                            . shows d

-- | @0.0.0.0@
inetAny             :: InetAddr
inetAny              = InetAddr 0

-- | @255.255.255.255@
inetBroadcast       :: InetAddr
inetBroadcast        = tupleToInetAddr (255,255,255,255)

-- | @255.255.255.255@
inetNone            :: InetAddr
inetNone             = tupleToInetAddr (255,255,255,255)

-- | @127.0.0.1@
inetLoopback        :: InetAddr
inetLoopback         = tupleToInetAddr (127,  0,  0,  1)

-- | @224.0.0.0@
inetUnspecificGroup :: InetAddr
inetUnspecificGroup  = tupleToInetAddr (224,  0,  0,  0)

-- | @224.0.0.1@
inetAllHostsGroup   :: InetAddr
inetAllHostsGroup    = tupleToInetAddr (224,  0,  0,  1)

-- | @224.0.0.255@
inetMaxLocalGroup   :: InetAddr
inetMaxLocalGroup    = tupleToInetAddr (224,  0,  0,255)

instance Storable InetAddr where
    sizeOf _ = sizeOf (undefined :: Word32)
    alignment _ = alignment (undefined :: Word32) 
    peek p = (InetAddr . ntohl) `fmap` peekByteOff p 0
    poke p (InetAddr ia) = pokeByteOff p 0 (htonl ia)

-- | Converts 'HostAddress' to representation-independent IPv4 quadruple.
-- For example for @127.0.0.1@ the function will return @(127, 0, 0, 1)@
-- regardless of host endianness.
inetAddrToTuple :: InetAddr -> (Word8, Word8, Word8, Word8)
inetAddrToTuple (InetAddr ia) =
    let byte i = fromIntegral (ia `shiftR` i) :: Word8
    in (byte 24, byte 16, byte 8, byte 0)

-- | Converts IPv4 quadruple to 'HostAddress'.
tupleToInetAddr :: (Word8, Word8, Word8, Word8) -> InetAddr
tupleToInetAddr (b3, b2, b1, b0) =
    let x `sl` i = fromIntegral x `shiftL` i :: Word32
    in InetAddr $ (b3 `sl` 24) .|. (b2 `sl` 16) .|. (b1 `sl` 8) .|. (b0 `sl` 0)

--------------------------------------------------------------------------------

-- | Independent of endianness. For example @::1@ is stored as @(0, 0, 0, 1)@.
--
-- For direct manipulation prefer 'inet6AddrToTuple' and 'tupleToInet6Addr'.
--
data Inet6Addr = Inet6Addr {-# UNPACK #-}!Word32
                           {-# UNPACK #-}!Word32
                           {-# UNPACK #-}!Word32
                           {-# UNPACK #-}!Word32 deriving (Eq, Ord)

instance Show Inet6Addr where
    showsPrec _ i6a = 
        let (a,b,c,d,e,f,g,h) = inet6AddrToTuple i6a
        in ("Inet6Addr " ++) . showHex a . (':':)
                             . showHex b . (':':)
                             . showHex c . (':':)
                             . showHex d . (':':)
                             . showHex e . (':':)
                             . showHex f . (':':)
                             . showHex g . (':':)
                             . showHex h

-- | @::@
inet6Any      :: Inet6Addr
inet6Any       = Inet6Addr 0 0 0 0

-- | @::1@
inet6Loopback :: Inet6Addr
inet6Loopback  = Inet6Addr 0 0 0 1

inet6AddrToTuple :: Inet6Addr -> (Word16, Word16, Word16, Word16,
                                        Word16, Word16, Word16, Word16)
inet6AddrToTuple (Inet6Addr w3 w2 w1 w0) =
    let high, low :: Word32 -> Word16
        high w = fromIntegral (w `shiftR` 16)
        low w = fromIntegral w
    in (high w3, low w3, high w2, low w2, high w1, low w1, high w0, low w0)

tupleToInet6Addr :: (Word16, Word16, Word16, Word16,
                        Word16, Word16, Word16, Word16) -> Inet6Addr
tupleToInet6Addr (w7, w6, w5, w4, w3, w2, w1, w0) =
    let add :: Word16 -> Word16 -> Word32
        high `add` low = (fromIntegral high `shiftL` 16) .|. (fromIntegral low)
    in  Inet6Addr (w7 `add` w6) (w5 `add` w4) (w3 `add` w2) (w1 `add` w0)

instance Storable Inet6Addr where
    sizeOf _    = #size struct in6_addr
    alignment _ = #alignment struct in6_addr

    peek p = do
        a <- peek32 p 0
        b <- peek32 p 1
        c <- peek32 p 2
        d <- peek32 p 3
        return $ Inet6Addr a b c d

    poke p (Inet6Addr a b c d) = do
        poke32 p 0 a
        poke32 p 1 b
        poke32 p 2 c
        poke32 p 3 d

--------------------------------------------------------------------------------

peekSockAddr :: HasCallStack => Ptr SockAddr -> IO SockAddr
peekSockAddr p = do
    family <- (#peek struct sockaddr, sa_family) p
    case family :: CSaFamily of
        (#const AF_INET) -> do
            addr <- (#peek struct sockaddr_in, sin_addr) p
            port <- (#peek struct sockaddr_in, sin_port) p
            return (SockAddrInet (PortNum port) addr)
        (#const AF_INET6) -> do
            port <- (#peek struct sockaddr_in6, sin6_port) p
            flow <- (#peek struct sockaddr_in6, sin6_flowinfo) p
            addr <- (#peek struct sockaddr_in6, sin6_addr) p
            scope <- (#peek struct sockaddr_in6, sin6_scope_id) p
            return (SockAddrInet6 (PortNum port) flow addr scope)

        _ -> do let errno = UV_EAI_ADDRFAMILY
                name <- uvErrName errno
                desc <- uvStdError errno
                throwUVError errno (IOEInfo name desc callStack)

pokeSockAddr :: HasCallStack => Ptr SockAddr -> SockAddr -> IO ()
pokeSockAddr p (SockAddrInet (PortNum port) addr) =  do
#if defined(darwin_HOST_OS)
    clearPtr p (#const sizeof(struct sockaddr_in))
#endif
#if defined(HAVE_STRUCT_SOCKADDR_SA_LEN)
    (#poke struct sockaddr_in, sin_len) p ((#const sizeof(struct sockaddr_in)) :: Word8)
#endif
    (#poke struct sockaddr_in, sin_family) p ((#const AF_INET) :: CSaFamily)
    (#poke struct sockaddr_in, sin_port) p port
    (#poke struct sockaddr_in, sin_addr) p addr
pokeSockAddr p (SockAddrInet6 (PortNum port) flow addr scope) =  do
#if defined(darwin_HOST_OS)
    clearPtr p (#const sizeof(struct sockaddr_in6))
#endif
#if defined(HAVE_STRUCT_SOCKADDR_SA_LEN)
    (#poke struct sockaddr_in6, sin6_len) p ((#const sizeof(struct sockaddr_in6)) :: Word8)
#endif
    (#poke struct sockaddr_in6, sin6_family) p ((#const AF_INET6) :: CSaFamily)
    (#poke struct sockaddr_in6, sin6_port) p port
    (#poke struct sockaddr_in6, sin6_flowinfo) p flow
    (#poke struct sockaddr_in6, sin6_addr) p (addr)
    (#poke struct sockaddr_in6, sin6_scope_id) p scope

withSockAddr :: SockAddr -> (Ptr SockAddr -> IO a) -> IO a
withSockAddr sa@(SockAddrInet _ _) f = do
    allocaBytesAligned
        (#size struct sockaddr_in)
        (#alignment struct sockaddr_in) $ \ p -> pokeSockAddr p sa >> f p
withSockAddr sa@(SockAddrInet6 _ _ _ _) f = do
    allocaBytesAligned 
        (#size struct sockaddr_in6) 
        (#alignment struct sockaddr_in6) $ \ p -> pokeSockAddr p sa >> f p

-- The peek32 and poke32 functions work around the fact that the RFCs
-- don't require 32-bit-wide address fields to be present.  We can
-- only portably rely on an 8-bit field, s6_addr.

s6_addr_offset :: Int
s6_addr_offset = (#offset struct in6_addr, s6_addr)

peek32 :: Ptr a -> Int -> IO Word32
peek32 p i0 = do
    let i' = i0 * 4
        peekByte n = peekByteOff p (s6_addr_offset + i' + n) :: IO Word8
        a `sl` i = fromIntegral a `shiftL` i
    a0 <- peekByte 0
    a1 <- peekByte 1
    a2 <- peekByte 2
    a3 <- peekByte 3
    return ((a0 `sl` 24) .|. (a1 `sl` 16) .|. (a2 `sl` 8) .|. (a3 `sl` 0))

poke32 :: Ptr a -> Int -> Word32 -> IO ()
poke32 p i0 a = do
    let i' = i0 * 4
        pokeByte n = pokeByteOff p (s6_addr_offset + i' + n)
        x `sr` i = fromIntegral (x `shiftR` i) :: Word8
    pokeByte 0 (a `sr` 24)
    pokeByte 1 (a `sr` 16)
    pokeByte 2 (a `sr`  8)
    pokeByte 3 (a `sr`  0)

--------------------------------------------------------------------------------

-- Port Numbers

-- | Use the @Num@ instance (i.e. use a literal or 'fromIntegral') to create a
-- @PortNumber@ value with the correct network-byte-ordering.
--
-- >>> 1 :: PortNumber
-- 1
-- >>> read "1" :: PortNumber
-- 1
newtype PortNumber = PortNum Word16 deriving (Eq, Ord, Typeable)
-- newtyped to prevent accidental use of sane-looking
-- port numbers that haven't actually been converted to
-- network-byte-order first.

aNY_PORT :: PortNumber
aNY_PORT = 0

instance Show PortNumber where
  showsPrec p pn = showsPrec p (portNumberToInt pn)

instance Read PortNumber where
  readsPrec n = map (\(x,y) -> (intToPortNumber x, y)) . readsPrec n

intToPortNumber :: Int -> PortNumber
intToPortNumber v = PortNum (htons (fromIntegral v))

portNumberToInt :: PortNumber -> Int
portNumberToInt (PortNum po) = fromIntegral (ntohs po)

foreign import #{CALLCONV} unsafe "ntohs" ntohs :: Word16 -> Word16
foreign import #{CALLCONV} unsafe "htons" htons :: Word16 -> Word16
foreign import #{CALLCONV} unsafe "ntohl" ntohl :: Word32 -> Word32
foreign import #{CALLCONV} unsafe "htonl" htonl :: Word32 -> Word32

instance Enum PortNumber where
    toEnum   = intToPortNumber
    fromEnum = portNumberToInt

instance Num PortNumber where
   fromInteger i = intToPortNumber (fromInteger i)
    -- for completeness.
   (+) x y   = intToPortNumber (portNumberToInt x + portNumberToInt y)
   (-) x y   = intToPortNumber (portNumberToInt x - portNumberToInt y)
   negate x  = intToPortNumber (-portNumberToInt x)
   (*) x y   = intToPortNumber (portNumberToInt x * portNumberToInt y)
   abs n     = intToPortNumber (abs (portNumberToInt n))
   signum n  = intToPortNumber (signum (portNumberToInt n))

instance Real PortNumber where
    toRational x = toInteger x % 1

instance Integral PortNumber where
    quotRem a b = let (c,d) = quotRem (portNumberToInt a) (portNumberToInt b) in
                  (intToPortNumber c, intToPortNumber d)
    toInteger a = toInteger (portNumberToInt a)

instance Storable PortNumber where
   sizeOf    _ = sizeOf    (undefined :: Word16)
   alignment _ = alignment (undefined :: Word16)
   poke p (PortNum po) = poke (castPtr p) po
   peek p = PortNum `fmap` peek (castPtr p)
    
--------------------------------------------------------------------------------

newtype SocketFamily = SocketFamily CInt deriving (Show, Read, Eq, Ord, Typeable)
newtype SocketType = SocketType CInt deriving (Show, Read, Eq, Ord, Typeable)
newtype SocketProtocol = SocketProtocol CInt deriving (Show, Read, Eq, Ord, Typeable)

instance Storable SocketFamily where                      
    sizeOf _ = sizeOf (undefined :: CInt)       
    alignment _ = alignment (undefined :: CInt) 
    peek ptr = SocketFamily `fmap` peek (castPtr ptr)             
    poke ptr (SocketFamily v) = poke (castPtr ptr) v

instance Storable SocketType where                      
    sizeOf _ = sizeOf (undefined :: CInt)       
    alignment _ = alignment (undefined :: CInt) 
    peek ptr = SocketType `fmap` peek (castPtr ptr)             
    poke ptr (SocketType v) = poke (castPtr ptr) v

instance Storable SocketProtocol where                      
    sizeOf _ = sizeOf (undefined :: CInt)       
    alignment _ = alignment (undefined :: CInt) 
    peek ptr = SocketProtocol `fmap` peek (castPtr ptr)             
    poke ptr (SocketProtocol v) = poke (castPtr ptr) v

-- | unspecified
pattern AF_UNSPEC :: SocketFamily
pattern AF_UNSPEC = SocketFamily (#const AF_UNSPEC)
-- | internetwork: UDP, TCP, etc
pattern AF_INET :: SocketFamily
pattern AF_INET = SocketFamily (#const AF_INET)
-- | Internet Protocol version 6
pattern AF_INET6 :: SocketFamily
pattern AF_INET6 = SocketFamily (#const AF_INET6)

pattern SOCK_STREAM :: SocketType
pattern SOCK_STREAM = SocketType (#const SOCK_STREAM)
pattern SOCK_DGRAM :: SocketType
pattern SOCK_DGRAM = SocketType (#const SOCK_DGRAM) 
pattern SOCK_RAW :: SocketType
pattern SOCK_RAW = SocketType (#const SOCK_RAW) 
pattern SOCK_RDM :: SocketType
pattern SOCK_RDM = SocketType (#const SOCK_RDM) 
pattern SOCK_SEQPACKET :: SocketType
pattern SOCK_SEQPACKET = SocketType (#const SOCK_SEQPACKET) 

pattern IPPROTO_DEF :: SocketProtocol
pattern IPPROTO_DEF = SocketProtocol 0
pattern IPPROTO_IP :: SocketProtocol
pattern IPPROTO_IP = SocketProtocol (#const IPPROTO_IP)
pattern IPPROTO_TCP :: SocketProtocol
pattern IPPROTO_TCP = SocketProtocol (#const IPPROTO_TCP)
pattern IPPROTO_UDP :: SocketProtocol
pattern IPPROTO_UDP = SocketProtocol (#const IPPROTO_UDP)