{-|
Module      : Net.Tcp.Definitions
Description : Implementation of mptcp netlink path manager
Maintainer  : matt
Stability   : testing
Portability : Linux

-}
{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}
module Net.Tcp.Definitions (
    TcpConnection (..)
    , ConnectionRole (..)
    , reverseTcpConnection
    , showTcpConnection
)

where

import Data.Aeson
import qualified Data.Text as TS
import Data.Word (Word16, Word32, Word8)
import GHC.Generics
import Net.IP
import Prelude

{- Describe a TCP connection, possibly an Mptcp subflow
  The equality implementation ignores several fields
-}
data TcpConnection = TcpConnection {
  -- TODO use libraries to deal with that ? filter from the command line for instance ?
  srcIp              :: IP -- ^Source ip
  , dstIp            :: IP -- ^Destination ip
  , srcPort          :: Word16  -- ^ Source port
  , dstPort          :: Word16  -- ^Destination port
  , priority         :: Maybe Word8 -- ^subflow priority
  , localId          :: Word8  -- ^ Convert to AddressFamily
  , remoteId         :: Word8
  -- TODO remove could be deduced from srcIp / dstIp ?
  , subflowInterface :: Maybe Word32 -- ^Interface of Maybe ? why a maybe ?
  -- add TcpMetrics member
  -- , tcpMetrics :: Maybe [SockDiagExtension]  -- ^Metrics retrieved from kernel

} deriving (Show, Generic, Ord)

tshow :: Show a => a -> TS.Text
tshow = TS.pack . Prelude.show

data ConnectionRole = Server | Client deriving (Show, Eq)


showTcpConnectionText :: TcpConnection -> TS.Text
showTcpConnectionText con =
  showIp ( srcIp con) <> ":" <> tshow (srcPort con) <> " -> " <> showIp (dstIp con) <> ":" <> tshow (dstPort con)
  where
    showIp = Net.IP.encode

showTcpConnection :: TcpConnection -> String
showTcpConnection = TS.unpack . showTcpConnectionText


reverseTcpConnection :: TcpConnection -> TcpConnection
reverseTcpConnection con = con {
  srcIp = dstIp con
  , dstIp = srcIp con
  , srcPort = dstPort con
  , dstPort = srcPort con
  , priority = Nothing
  , localId = remoteId con
  , remoteId = localId con
  , subflowInterface = Nothing
}

instance FromJSON TcpConnection
instance ToJSON TcpConnection

-- TODO create a specific function for it
-- ignore the rest
instance Eq TcpConnection where
  x == y = srcIp x == srcIp y && dstIp x == dstIp y
            && srcPort x == srcPort y && dstPort x == dstPort y
  -- /= = not ==