{-|
Description : Implementation of mptcp netlink path manager
Maintainer  : matt
Stability   : testing
Portability : Linux

Monitors new MPTCP connections and runs a specific monitor instance

To interact
GENL_ADMIN_PERM
The operation requires the CAP_NET_ADMIN privilege

Helpful links:

- inspired by https://stackoverflow.com/questions/6009384/exception-handling-in-haskell
- super nice tutorial on optparse applicative: https://github.com/pcapriotti/optparse-applicative#regular-options
- How to use Map https://lotz84.github.io/haskellbyexample/ex/maps
= How to update a single field https://stackoverflow.com/questions/14955627/shorthand-way-for-assigning-a-single-field-in-a-record-while-copying-the-rest-o
- get tcp stats via netlink https://www.vividcortex.com/blog/2014/09/22/using-netlink-to-optimize-socket-statistics/
eNETLINK_INET_DIAG


Concurrent values
- https://www.oreilly.com/library/view/parallel-and-concurrent/9781449335939/ch07.html
- https://stackoverflow.com/questions/22171895/using-tchan-with-timeout
- https://www.reddit.com/r/haskellquestions/comments/5rh1d4/concurrency_and_shared_state/

Mutable states:
- https://blog.jakuba.net/2014/07/20/Mutable-State-in-Haskell/
- http://mainisusuallyafunction.blogspot.com/2011/10/safe-top-level-mutable-variables-for.html

http://kristrev.github.io/2013/07/26/passive-monitoring-of-sockets-on-linux

iproute2/misc/ss.c to see how `ss` utility interacts with the kernel
-- https://downloads.haskell.org/~ghc/latest/docs/html/libraries/process-1.6.5.0/System-Process.html

Aeson tutorials:
-- https://haskell.fpcomplete.com/library/aeson
- https://lotz84.github.io/haskellbyexample/ex/timers

- https://lotz84.github.io/haskellbyexample/ex/maps


Useful functions in Map
- member / elemes / keys / assocs / keysSet / toList
-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE OverloadedStrings #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}

module Main where

import Prelude hiding (concat, init)
import Options.Applicative hiding (value, ErrorMsg, empty)
import qualified Options.Applicative (value)

-- For TcpState, FFI generated
import Net.SockDiag
import Net.Mptcp
--  hiding(mapIPtoInterfaceIdx)
import Net.Mptcp.PathManager
import Net.Mptcp.PathManager.Default
import Net.Tcp
import Net.IP
import Net.IPv4 hiding (print)
-- import Net.IPAddress

import Net.SockDiag.Constants
import Net.Tcp.Constants
import Net.Mptcp.Constants


-- for readList
import Text.Read
-- pack
import Data.Text ()

-- for replicateM
import Control.Monad (foldM)
-- fromMaybe, 
import Data.Maybe (catMaybes)
-- import Data.Foldable (concat)
import Foreign.C.Types (CInt)
-- for eOK, ePERM
import Foreign.C.Error
-- import qualified System.Linux.Netlink as NL
import System.Linux.Netlink as NL
import System.Linux.Netlink.GeNetlink as GENL
import System.Linux.Netlink.Constants as NLC
-- import System.Linux.Netlink.Constants (eRTM_NEWADDR)
-- import System.Linux.Netlink.Helpers
import System.Log.FastLogger
import System.Linux.Netlink.GeNetlink.Control
import qualified System.Linux.Netlink.Simple as NLS
import qualified System.Linux.Netlink.Route as NLR

import System.Process
import System.Exit
import Data.Word (Word16, Word32)
-- import qualified Data.Bits as Bits -- (shiftL, )
-- import Data.Bits ((.|.))
import Data.Serialize.Get (runGet)
import Data.Serialize.Put
-- import Data.Either (fromRight)
import Data.ByteString (ByteString)
import Data.ByteString.Lazy (writeFile)
-- import Data.ByteString.Char8 (unpack, init)
-- import System.Posix.

-- import qualified Data.ByteString.Char8 as BSC
import qualified Data.Map as Map
import qualified Data.Set as Set

import qualified Data.Text
import Data.Bits (Bits(..))

-- https://hackage.haskell.org/package/bytestring-conversion-0.1/candidate/docs/Data-ByteString-Conversion.html#t:ToByteString
-- contains ToByteString / FromByteString
-- import Data.ByteString.Conversion
import Debug.Trace
-- import Control.Exception

import Control.Concurrent
-- import Control.Exception (assert)
-- import Control.Concurrent.Chan
-- import Data.IORef
-- import Control.Concurrent.Async
import System.IO.Unsafe
import System.IO.Temp ()
-- for takeFilename
import System.FilePath ()

-- , Handle
import System.IO (stderr)
import Data.Aeson
-- to merge MptcpConnection export and Metrics
import Data.Aeson.Extra.Merge  (lodashMerge)

import Data.Aeson.Encode.Pretty (encodePretty)
-- import GHC.Generics

-- for getEnvDefault, to get TMPDIR value.
-- we could pass it as an argument
-- import System.Environment.Blank(getEnvDefault)

-- trying hslogger
import System.Log.Logger (
    -- rootLoggerName
    infoM
    , debugM
    , Priority(DEBUG)
    , Priority(INFO)
    , setLevel, updateGlobalLogger
    )
import System.Log.Handler.Simple (
    streamHandler
    -- , GenericHandler
    )
-- for writeUTF8File
-- import Distribution.Simple.Utils
-- import Distribution.Utils.Generic
-- import System.Log.Handler (setFormatter)

-- STM = State Thread Monad ST monad
-- import Data.IORef
-- MVar can be empty contrary to IORef !
-- globalMptcpSock :: IORef MptcpSocket
-- from unordered containers
-- import qualified Data.HashMap.Lazy as HML
import qualified Data.HashMap.Strict as HM

{-# NOINLINE globalMptcpSock #-}
globalMptcpSock :: MVar MptcpSocket
globalMptcpSock = unsafePerformIO newEmptyMVar
-- du coup cette socket n'aurait meme plus besoin d'etre globale en fait ?

-- TODO remove
-- globalMetricsSock :: MVar NetlinkSocket
-- globalMetricsSock = unsafePerformIO newEmptyMVar

-- {-# NOINLINE globalInterfaces #-}
-- globalInterfaces :: MVar AvailablePaths
-- globalInterfaces = unsafePerformIO newEmptyMVar

iperfClientPort :: Word16
iperfClientPort = 5500

iperfServerPort :: Word16
iperfServerPort = 5201

-- |
onSuccessSleepingDelay :: Int
onSuccessSleepingDelay = 300


-- When it couldn't set the correct value
onFailureSleepingDelay :: Int
onFailureSleepingDelay = 100

-- should be able to ignore based on regex
-- TODO see interfacesToIgnore 
-- interfacesToIgnore :: [String]
-- interfacesToIgnore = [
--   "virbr0"
--   , "virbr1"
--   , "nlmon0"
--   , "ppp0"
--   , "lo"
--   ]

-- |the path manager used in the 
pathManager :: PathManager
pathManager = meshPathManager

-- |Helper to pass information across functions
data MyState = MyState {
  socket :: MptcpSocket -- ^Socket
  -- ThreadId/MVar
  , connections :: Map.Map MptcpToken (ThreadId, MVar MptcpConnection)
  -- |Arguments passed to the program
  , cliArguments :: CLIArguments
}

-- https://stackoverflow.com/questions/51407547/how-to-update-a-field-of-a-json-object
addJsonKey :: Data.Text.Text -> Value -> Value -> Value
addJsonKey key val (Object xs) = Object $ HM.insert key val xs
addJsonKey _ _ xs = xs

authorizedCon1 :: TcpConnection
authorizedCon1 = TcpConnection {
        srcIp = fromIPv4 $ Net.IPv4.ipv4 192 168 0 128
        , dstIp = fromIPv4 $ Net.IPv4.ipv4 202 214 86 51
        , srcPort = iperfClientPort
        , dstPort = iperfServerPort
        , priority = Nothing
        , subflowInterface = Nothing
        , localId = 0
        , remoteId = 0
    }

authorizedCon2 :: TcpConnection
authorizedCon2 = authorizedCon1 { srcIp = fromIPv4 $ Net.IPv4.ipv4 192 168 0 130 }

filteredConnections :: [TcpConnection]
filteredConnections = [
    authorizedCon1
    ]


-- inspired by CtrlPacket
  -- token :: MptcpToken
-- MptcpNewConnection
-- data MptcpPacket = MptcpPacket {
--       mptcpHeader     :: Header
--     , mptcpGeHeader   :: GenlHeader
--     , mptcpData   :: MptcpData

-- data MptcpData = MptcpData {
--     mptcpAttributes :: [MptcpAttr]
--   } deriving (Eq)

-- TODO are they generated
dumpCommand :: MptcpGenlEvent -> String
dumpCommand x = show x ++ " = " ++ show (fromEnum x)
-- dumpCommand MPTCP_CMD_UNSPEC  = " MPTCP_CMD_UNSPEC  0"
-- dumpCommand MPTCP_EVENT_SUB_ERROR = show MPTCP_EVENT_SUB_ERROR + show fromEnum MPTCP_EVENT_SUB_ERROR

dumpMptcpCommands :: MptcpGenlEvent -> String
dumpMptcpCommands MPTCP_CMD_EXIST = dumpCommand MPTCP_CMD_EXIST
dumpMptcpCommands x = dumpCommand x ++ "\n" ++ dumpMptcpCommands (succ x)


-- todo use it as a filter
data CLIArguments = CLIArguments {
  -- | useless
  command    :: String
  , serverIP     :: IPv4

  -- | Path to a program in charge of generating congestion window limits on a 
  -- per path basis
  -- The program will be called with a json file as input and must echo on stdout
  -- an array of the form [ 10, 30, 40]
  , optimizer    :: FilePath

  -- | Folder where to log files
  , out    :: FilePath

  -- , clientIP      :: IPv4
  , quiet      :: Bool
  , enthusiasm :: Int
  }


-- TODO use 3rd party library levels
-- data Verbosity = Normal | Debug

loggerName :: String
loggerName = "main"

dumpSystemInterfaces :: IO()
dumpSystemInterfaces = do
  putStrLn "Dumping interfaces"
  -- isEmptyMVar globalInterfaces
  res <- tryReadMVar globalInterfaces 
  case res of
    Nothing -> putStrLn "No interfaces"
    Just interfaces -> Prelude.print interfaces

  putStrLn "End of dump"


-- TODO register subcommands instead
-- see https://stackoverflow.com/questions/31318643/optparse-applicative-how-to-handle-no-arguments-situation-in-arrow-syntax
--  ( command "add" (info addOptions ( progDesc "Add a file to the repository" ))
 -- <> command "commit" (info commitOptions ( progDesc "Record changes to the repository" ))
-- can use several constructors depending on the PM ?
-- ByteString
sample :: Parser CLIArguments
sample = CLIArguments
      <$> argument str
          ( metavar "CMD"
         <> help "What to do" )
      -- TODO should accept hostname etc
      <*> argument (eitherReader $ \x -> case (Net.IPv4.decodeString x) of
                                            Nothing -> Left "could not parse"
                                            Just ip -> Right ip)
        ( metavar "ServerIP"
         <> help "ServerIP to let through (e.g.: 202.214.86.51 )" )
      <*> strOption
          ( long "optimizer"
          <> short 'p'
         <> help "Path to the userspace program"
         <> showDefault
         <> Options.Applicative.value "fake_solver"
         <> metavar "PROGRAM" )
      <*> strOption
          ( long "out"
          <> short 'o'
         <> help "Where to store the files"
         <> showDefault
         <> Options.Applicative.value "/tmp"
         <> metavar "PROGRAM" )
      <*> switch
          ( long "verbose"
         <> short 'v'
         <> help "Whether to be quiet" )
      <*> option auto
          ( long "enthusiasm"
         <> help "How enthusiastically to greet"
         <> showDefault
         <> Options.Applicative.value 1
         <> metavar "INT" )


opts :: ParserInfo CLIArguments
opts = info (sample <**> helper)
  ( fullDesc
  <> progDesc "Print a greeting for TARGET"
  <> header "hello - a test for optparse-applicative" )



-- inspired by makeNL80211Socket Create a 'NL80211Socket' this opens a genetlink
-- socket and gets the family id
-- TODO should record the token too
-- TODO should join the group !!
makeMptcpSocket :: IO MptcpSocket
makeMptcpSocket = do
    -- for legacy reasons this opens a route socket
  sock <- GENL.makeSocket
  res <- getFamilyIdS sock mptcpGenlName
  case res of
    Nothing -> error $ "Could not find family " ++ mptcpGenlName
    Just fid -> return  (MptcpSocket sock (trace ("family id"++ show fid ) fid))


-- Used tuples
-- sock <- makeSocket
makeMetricsSocket :: IO NetlinkSocket
makeMetricsSocket = do
    -- NETLINK_SOCK_DIAG == NETLINK_INET_DIAG
  sock <- makeSocketGeneric eNETLINK_SOCK_DIAG
  return sock

-- used in tests
startMonitorExternalProcess :: MptcpToken -> CreateProcess
startMonitorExternalProcess token =
  let
    params = proc "daemon" [ show token ]
    -- todo pass the token via the environment
    newParams = params {
        -- cmdspec = RawCommand "monitor" [ show token ]
        new_session = True
        -- cwd
        -- env
    }
  in
    -- return "toto"
    newParams

-- A utility function - threadDelay takes microseconds, which is slightly annoying.
sleepMs :: Int -> IO()
sleepMs n = threadDelay (n * 1000)

-- | here we may want to run mptcpnumerics to get some results
updateSubflowMetrics :: NetlinkSocket -> TcpConnection -> IO SockDiagMetrics
updateSubflowMetrics sockMetrics subflow = do
    putStrLn "Updating subflow metrics"
    let queryPkt = genQueryPacket (Right subflow) [TcpListen, TcpEstablished]
         [InetDiagCong, InetDiagInfo, InetDiagMeminfo]
    sendPacket sockMetrics queryPkt
    putStrLn "Sent the TCP SS request"

    -- exported from my own version !!
    -- TODO display number of answers
    putStrLn "Starting inspecting answers"
    answers <- recvMulti sockMetrics
    let metrics_m = inspectIdiagAnswers answers
    -- filter ? keep only valud ones ?
    return $ head (catMaybes metrics_m)
    -- putStrLn "Finished inspecting answers"


{- |
  Starts monitoring a specific MPTCP connection
  Maybe should expect a pathManager instance (and logger
FilePath -- ^Path towards the program to get cwnd limits
-}
startMonitorConnection :: FilePath   -- ^ Where to write files
                          -> MptcpSocket
                          -> NetlinkSocket
                          -> MVar MptcpConnection -> IO ()
startMonitorConnection tmpdir mptcpSock sockMetrics mConn = do
    let (MptcpSocket sock familyId) = mptcpSock
    myId <- myThreadId
    putStr $ show myId ++ "Start monitoring connection..."
    -- as long as conn is not empty we keep going ?
    -- for this connection
    -- query metrics for the whole MPTCP connection
    con <- readMVar mConn
    putStrLn "Showing MPTCP connection"
    putStrLn $ show con ++ "..."
    let token = connectionToken con

    -- TODO this is the issue
    -- not sure it's the master with a set
    let masterSf = Set.elemAt 0 (subflows con)

    -- Get updated metrics
    lastMetrics <- mapM (updateSubflowMetrics sockMetrics) (Set.toList $ subflows con)

    putStrLn "Running mptcpnumerics"

    -- Then refresh the cwnd objective
    cwnds_m <- getCapsForConnection tmpdir con lastMetrics
    case cwnds_m of
        Nothing -> do
            putStrLn "Couldn't fetch the values"
            sleepMs onFailureSleepingDelay
        Just cwnds -> do

            putStrLn $ "Requesting to set cwnds..." ++ show cwnds
            -- TODO fix
            -- KISS for now (capCwndPkt mptcpSock )
            let cwndPackets  = map (\(cwnd, sf) -> capCwndPkt mptcpSock con cwnd sf) (zip cwnds (Set.toList $ subflows con))

            mapM_ (sendPacket sock) cwndPackets

            sleepMs onSuccessSleepingDelay
    putStrLn "Finished monitoring token "

    -- call ourself again
    startMonitorConnection tmpdir mptcpSock sockMetrics mConn




{-
  | This should return a list of cwnd to respect a certain scenario
 1. save the connection to a JSON file and pass it to mptcpnumerics

-}
getCapsForConnection :: FilePath
                        -> MptcpConnection
                        -> [SockDiagMetrics]
                        -> IO (Maybe [Word32])
getCapsForConnection tmpdir mptcpConn metrics = do
    -- returns a bytestring
    -- let (MptcpConnectionWithMetrics  mptcpConn metrics) = conWithMetrics
    let jsonConn = (toJSON mptcpConn)
    let merged = lodashMerge jsonConn (object [ "subflows" .= metrics ])
  -- (toJSON jsonConn) ++ (toJSON metrics)

    -- let jsonBs = Data.Aeson.encode merged
    let jsonBs = encodePretty merged
    -- let bs = Data.Aeson.encode jsonConn
    let subflowCount = length $ subflows mptcpConn

    -- TODO either pass it via env or via args
    -- let tmpdir = "/tmp"
    -- let tmpdir = getEnvDefault "TMPDIR" "/tmp"

    let filename = tmpdir ++ "/" ++ "mptcp_" ++ (show $ connectionToken mptcpConn) ++ "_" ++ (show $ subflowCount)  ++ ".json"
    infoM "main" $ "Saving to " ++ filename

    -- tempdir <- getCanonicalTemporaryDirectory
    -- see https://github.com/feuerbach/temporary/blob/2ebee43b92b878f0093b3ce66d613d553f82152f/tests/test.hs#L63
    -- for an example
    -- takeDirectory fp `equalFilePath` sys_tmp_dir
    -- fp <- withSystemTempDirectory tempdir "toto" $ \fp -> do
    --     let fn = takeFileName fp
        -- Data.ByteString.Lazy.writeFile fn

    Data.ByteString.Lazy.writeFile filename jsonBs

    -- TODO to keep it simple it should return a list of CWNDs to apply
    -- readProcessWithExitCode  binary / args / stdin
    (exitCode, stdout, stderrContent) <- readProcessWithExitCode (get_caps_prog mptcpConn) [filename, show subflowCount] ""

    putStrLn $ "exitCode: " ++ show exitCode
    putStrLn $ "stdout:\n" ++ stdout
    -- http://hackage.haskell.org/package/base/docs/Text-Read.html
    let values = (case exitCode of
        -- for now simple, we might read json afterwards
                      ExitSuccess -> (readMaybe stdout) :: Maybe [Word32]
                      ExitFailure val -> error $ "stdout:" ++ stdout ++ " stderr: " ++ stderrContent
                      )
    return values

-- type Attributes = Map Int ByteString
-- the library contains showAttrs / showNLAttrs
showAttributes :: Attributes -> String
showAttributes attrs =
  let
    mapped = Map.foldrWithKey (\k v -> (dumpAttribute k v ++)  ) "\n " attrs
  in
    mapped

putW32 :: Word32 -> ByteString
putW32 x = runPut (putWord32host x)

-- removeSubflow :: MptcpSocket -> MptcpToken -> LocId -> IO [GenlPacket NoData]
-- removeSubflow (MptcpSocket socket fid) token locId = let

-- I want to override the GenlHeader version
newtype GenlHeaderMptcp = GenlHeaderMptcp GenlHeader
instance Show GenlHeaderMptcp where
  show (GenlHeaderMptcp (GenlHeader cmd ver)) =
    "Header: Cmd = " ++ show cmd ++ ", Version: " ++ show ver ++ "\n"

--
inspectAnswers :: [GenlPacket NoData] -> IO ()
inspectAnswers packets = do
  mapM_ inspectAnswer packets
  putStrLn "Finished inspecting answers"

-- showPacketCustom :: GenlPacket NoData -> String
-- showPacketCustom pkt = let
--   hdr = (genlDataHeader pkt )
--   in showPacket pkt

showHeaderCustom :: GenlHeader -> String
showHeaderCustom = show

inspectAnswer :: GenlPacket NoData -> IO ()
inspectAnswer (Packet _ (GenlData hdr NoData) attributes) = let
    cmd = genlCmd hdr
  in
    putStrLn $ "Inspecting answer custom:\n" ++ showHeaderCustom hdr
            ++ "Supposing it's a mptcp command: " ++ dumpCommand ( toEnum $ fromIntegral cmd)

inspectAnswer pkt = putStrLn $ "Inspecting answer:\n" ++ showPacket pkt



-- should have this running in parallel
queryAddrs :: NLR.RoutePacket
queryAddrs = NL.Packet
    (NL.Header NLC.eRTM_GETADDR (NLC.fNLM_F_ROOT .|. NLC.fNLM_F_MATCH .|. NLC.fNLM_F_REQUEST) 0 0)
    (NLR.NAddrMsg 0 0 0 0 0)
    mempty


-- |Deal with events for already registered connections
-- Warn: MPTCP_EVENT_ESTABLISHED registers a "null" interface
-- TODO return a Maybe ?
-- or a list of packets to send
-- TODO return the MVar ?
--
-- availablePaths <- readMVar globalInterfaces
-- TODO put globalInterfaces in MyState ?
    -- let (MptcpSocket mptcpSockRaw fid) = mptcpSock
    -- let pkts = (onMasterEstablishement pathManager) mptcpSock mptcpConn availablePaths

    -- putStrLn "List of requests made on new master:"
    -- mapM_ (sendPacket $ mptcpSockRaw) pkts


-- TODO maybe the path manager should be part of the MptcpConnection
dispatchPacketForKnownConnection :: MptcpSocket
                                    -> MptcpConnection
                                    -> MptcpGenlEvent
                                    -> Attributes
                                    -> AvailablePaths
                                    -- -> Map.Map MptcpAttr MptcpAttribute
                                    -- -> MptcpConnection
                                    -> (Maybe MptcpConnection, [MptcpPacket])
dispatchPacketForKnownConnection mptcpSock con event attributes availablePaths = let
        token = connectionToken con
        subflow = subflowFromAttributes attributes
    in
    case event of

      -- let the Path manager kick in
      MPTCP_EVENT_ESTABLISHED -> let
              -- onMasterEstablishement mptcpSock 
              -- Needs IO because of NetworkInterface
              newPkts = (onMasterEstablishement pathManager) mptcpSock con availablePaths
          in
              (Just con, newPkts)

      -- TODO trigger the pathManager again, fix the remote interpretation
      MPTCP_EVENT_ANNOUNCED -> let
          -- what if it's local
            remId = remoteIdFromAttributes attributes
            -- TODO 
            -- newConn = mptcpConnAddRemoteId con remId
            newConn = con
          in
            (Just newConn, [])

      MPTCP_EVENT_CLOSED -> (Nothing, [])

      MPTCP_EVENT_SUB_ESTABLISHED -> let
                newCon = mptcpConnAddSubflow con subflow
            in
                (Just newCon,[])
        -- let newState = oldState
        -- putMVar con newCon
        -- let newState = oldState { connections = Map.insert token newCon (connections oldState) }
        -- TODO we should insert the
        -- newConn <-
        -- return newState

      -- TODO remove
      MPTCP_EVENT_SUB_CLOSED -> let
              newCon = mptcpConnRemoveSubflow con subflow
            in
              (Just newCon, [])

      -- MPTCP_CMD_EXIST -> con

      _ -> error $ "should not happen " ++ show event


acceptConnection :: TcpConnection -> Bool
-- acceptConnection subflow = subflow `notElem` filteredConnections
acceptConnection subflow = True

-- |
mapSubflowToInterfaceIdx :: IP -> IO (Maybe Word32)
mapSubflowToInterfaceIdx ip = do

  res <- tryReadMVar globalInterfaces
  case res of
    Nothing -> error "Couldn't access the list of interfaces"
    Just interfaces -> return $ mapIPtoInterfaceIdx interfaces ip



-- TODO reestablish later on
-- open additionnal subflows
-- createNewSubflows :: MptcpSocket -> MptcpConnection -> IO ()
-- createNewSubflows mptcpSock mptcpConn = do
--     availablePaths <- readMVar globalInterfaces
--     let (MptcpSocket mptcpSockRaw fid) = mptcpSock
--     let pkts = (onMasterEstablishement pathManager) mptcpSock mptcpConn availablePaths

--     putStrLn "List of requests made on new master:"
--     mapM_ (sendPacket $ mptcpSockRaw) pkts


-- Maybe
registerMptcpConnection :: MyState -> MptcpToken -> TcpConnection -> IO MyState
registerMptcpConnection oldState token subflow = let
        (MyState mptcpSock conns cliArgs) = oldState
    in
    if acceptConnection subflow == False
        then do
            putStrLn $ "filtered out connection" ++ show subflow
            return oldState
        else (do
                -- should we add the subflow yet ? it doesn't have the correct interface idx
                mappedInterface <- mapSubflowToInterfaceIdx (srcIp subflow)
                let fixedSubflow = subflow { subflowInterface = mappedInterface }
                -- let newMptcpConn = (MptcpConnection token [] Set.empty Set.empty)
                let newMptcpConn = mptcpConnAddSubflow (
                      MptcpConnection token Set.empty Set.empty Set.empty (optimizer cliArgs)
                      ) fixedSubflow

                newConn <- newMVar newMptcpConn
                putStrLn $ "Connection established !!\n"

                -- create a new
                sockMetrics <- makeMetricsSocket
                -- start monitoring connection
                threadId <- forkOS (startMonitorConnection (out cliArgs) mptcpSock sockMetrics newConn)

                putStrLn $ "Inserting new MVar "
                let newState = oldState {
                    connections = Map.insert token (threadId, newConn) (connections oldState)
                }
                return newState)

-- |Treat MPTCP events depending on if the connection is known or not
--
dispatchPacket :: MyState -> MptcpPacket -> IO MyState
dispatchPacket oldState (Packet hdr (GenlData genlHeader NoData) attributes) = let
        cmd = toEnum $ fromIntegral $ genlCmd genlHeader
        (MyState mptcpSock conns _) = oldState
        (MptcpSocket mptcpSockRaw fid) = mptcpSock

        -- i suppose token is always available right ?
        token = readToken $ Map.lookup (fromEnum MPTCP_ATTR_TOKEN) attributes
        maybeMatch = Map.lookup token (connections oldState)
    in do
        putStrLn $ "Fetching available paths"
        availablePaths <- readMVar globalInterfaces

        putStrLn $ "dispatch cmd " ++ show cmd ++ " for token " ++ show token

        case maybeMatch of
            -- Unknown token
            Nothing -> do

                putStrLn $ "Unknown token/connection " ++ show token
                case cmd of

                  MPTCP_EVENT_ESTABLISHED -> do
                      putStrLn "Ignoring Creating EVENT"
                                  -- let newMptcpConn = (MptcpConnection token [] Set.empty Set.empty)
                      return oldState

                  MPTCP_EVENT_CREATED -> let
                      subflow = subflowFromAttributes attributes
                    in
                      registerMptcpConnection oldState token subflow
                  _ -> return oldState

            Just (threadId, mvarConn) -> do
                putStrLn $ "MATT: Received request for a known connection "
                mptcpConn <- takeMVar mvarConn

                putStrLn $ "Forwarding to dispatchPacketForKnownConnection "
                case dispatchPacketForKnownConnection mptcpSock mptcpConn cmd attributes availablePaths of
                  (Nothing, _) -> do
                        putStrLn $ "Killing thread " ++ show threadId
                        killThread threadId
                        return $ oldState { connections = Map.delete token (connections oldState) }

                  (Just newConn, pkts) -> do
                        putStrLn "putting mVar"
                        putMVar mvarConn newConn
                        -- TODO update state

                        putStrLn "List of requests made on new master:"
                        mapM_ (\pkt -> sendPacket mptcpSockRaw (trace ("TOTO" ++ show pkt) pkt)) pkts
                        let newState = oldState {
                            connections = Map.insert token (threadId, mvarConn) (connections oldState)
                        }
                        return newState

                -- case cmd of

                --     MPTCP_EVENT_CREATED -> error "We should not receive MPTCP_EVENT_CREATED from here !!!"
                --     MPTCP_EVENT_SUB_CLOSED -> do
                --         putStrLn $ "SUBFLOW WAS CLOSED"
                --         return oldState

                --     MPTCP_EVENT_ANNOUNCED -> do
                --         -- what if it's local
                --           case makeAttributeFromMaybe MPTCP_ATTR_REM_ID attributes of
                --               Nothing -> con
                --               Just (RemoteLocatorId remId) -> do
                --                   mptcpConnAddRemoteId con remId
                --                   createNewSubflows mptcpSock mptcpConn
                --               _ -> error "Wrong translation"

                --     MPTCP_EVENT_CLOSED -> do
                --         putStrLn $ "Killing thread " ++ show threadId
                --         killThread threadId
                --         return $ oldState { connections = Map.delete token (connections oldState) }
                --     MPTCP_EVENT_ESTABLISHED -> do
                --         putStrLn "Connexion established"
                        -- mptcpConn <- readMVar mvarConn
                        -- createNewSubflows mptcpSock mptcpConn >> return oldState

                -- TODO update connection
                    -- TODO filter first
                    -- _ -> do

                    --     putStrLn $ "Forwarding to dispatchPacketForKnownConnection "
                        -- -- TODO convert attributes
                        -- -- convertAttributesIntoMap 
                        -- let newConn = dispatchPacketForKnownConnection mptcpSock mptcpConn cmd attributes



dispatchPacket s (DoneMsg err) =
  putStrLn "Done msg" >> return s


-- EOK shouldn't be an ErrorMsg when it receives EOK ?
dispatchPacket s (ErrorMsg hdr errCode errPacket) = do
  if errCode == 0 then
    putStrLn $ "Received acknowledgement for " ++ show hdr
  else
    putStrLn $ "Error msg of type " ++ showErrCode errCode ++ " Packet content:\n" ++ show errPacket

  return s

-- ++ show errPacket
showError :: Show a => Packet a -> IO ()
showError (ErrorMsg hdr errCode errPacket) =
  putStrLn $ "Error msg of type " ++ showErrCode errCode ++ " Packet content:\n"
showError _ = error "Not the good overload"

-- netlink must contain sthg for it
-- /usr/include/asm/errno.h
showErrCode :: CInt -> String
showErrCode err
  | Errno err == ePERM = "EPERM"
  | Errno err == eOK = "EOK"
  | otherwise = show err

-- showErrCode err = case err of
-- -- show err
--   ePERM -> "EPERM"
--   eNOTCONN -> "NOT connected"

inspectResult :: MyState -> Either String MptcpPacket -> IO MyState
inspectResult myState result = case result of
      Left ex -> putStrLn ("An error in parsing happened" ++ show ex) >> return myState
      Right myPack -> dispatchPacket myState myPack


-- |Infinite loop basically
doDumpLoop :: MyState -> IO MyState
doDumpLoop myState = do
    let (MptcpSocket simpleSock fid) = socket myState

    results <- recvOne' simpleSock ::  IO [Either String MptcpPacket]

    -- TODO retrieve packets
    -- here we should update the state according
    -- mapM_ (inspectResult myState) results
    -- (Foldable t, Monad m) => (b -> a -> m b) -> b -> t a -> m b
    modifiedState <- foldM inspectResult myState results

    doDumpLoop modifiedState

-- regarder dans query/joinMulticastGroup/recvOne
listenToEvents :: MyState -> CtrlAttrMcastGroup -> IO ()
listenToEvents state my_group = do
  -- joinMulticastGroup  returns IO ()
  -- TODO should check it works correctly !
  joinMulticastGroup sock (grpId my_group)
  putStrLn $ "Joined grp " ++ grpName my_group
  _ <- doDumpLoop state
  putStrLn "end of listenToEvents"
  where
    (MptcpSocket sock fid) = socket state


-- testing
listenToMetricEvents :: NetlinkSocket -> CtrlAttrMcastGroup  -> IO ()
listenToMetricEvents sock myGroup = do
  putStrLn "listening to metric events"
  joinMulticastGroup sock (grpId myGroup)
  putStrLn $ "Joined grp " ++ grpName myGroup
  -- _ <- doDumpLoop globalState
  -- putStrLn "TOTO"
  -- where
  --   -- mptcpSocket = MptcpSocket sock fid
  --   globalState = MyState mptcpSocket Map.empty


createLogger :: IO LoggerSet
createLogger = newStdoutLoggerSet defaultBufSize


-- for big endian
-- https://mail.haskell.org/pipermail/beginners/2010-October/005571.html
-- foldl' :: (b -> a -> b) -> b -> Maybe a -> b
-- fromOctetsBE :: [Word8] -> Word32
-- fromOctetsBE = foldl' accum 0
--   where
--     accum a o = (a `Bits.shiftL` 8) .|. fromIntegral o
--     -- maybe I could use putIArrayOf instead

-- fromOctetsLE :: [Word8] -> Word32
-- fromOctetsLE = fromOctetsBE . reverse



dumpExtensionAttribute :: Int -> ByteString -> SockDiagExtension
dumpExtensionAttribute attrId value = let
        eExtId = (toEnum attrId :: SockDiagExtensionId)
        ext_m = loadExtension attrId value
    in
        case ext_m of
            Nothing -> error $ "Could not load " ++ show eExtId ++ " (unsupported)\n"
            Just ext -> ext
            -- traceId (show eExtId) ++ " " ++ showExtension ext ++ " \n"

loadExtensionsFromAttributes :: Attributes -> [SockDiagExtension]
loadExtensionsFromAttributes attrs =
    let
        -- $ loadExtension
        mapped = Map.foldrWithKey (\k v -> ([dumpExtensionAttribute k v] ++ )) [] attrs
    in
        mapped


{- Parses the requested informations
-}
inspectIDiagAnswer :: Packet SockDiagMsg -> Maybe SockDiagMetrics
inspectIDiagAnswer (Packet hdr cus attrs) =
  Just $ SockDiagMetrics cus (loadExtensionsFromAttributes attrs)
  -- Just cus
inspectIDiagAnswer p = Nothing

-- inspectIDiagAnswer (DoneMsg err) = putStrLn "DONE MSG"
-- (GenlData NoData)
-- inspectIdiagAnswer (Packet hdr (GenlData ghdr NoData) attributes) = putStrLn $ "Inspecting answer:\n"
-- inspectIdiagAnswer (Packet _ (GenlData hdr NoData) attributes) = let
--     cmd = genlCmd hdr
--   in
--     putStrLn $ "Inspecting answer custom:\n" ++ showHeaderCustom hdr
--             ++ "Supposing it's a mptcp command: " ++ dumpCommand ( toEnum $ fromIntegral cmd)


-- |Convenience wrapper
data SockDiagMetrics = SockDiagMetrics {
  sockDiagMsg :: SockDiagMsg
  -- subflowSubflow :: TcpConnection
  , sockdiagMetrics :: [SockDiagExtension]
}

-- type SockDiagExtension2 = SockDiagExtension 
instance ToJSON SockDiagExtension where
  -- tcpi_rtt / tcpi_rttvar / tcpi_snd_ssthresh / tcpi_snd_cwnd 
  -- tcpi_state , tcpi_rto
  -- rename arg to tcp_info
  toJSON (tcp_info@DiagTcpInfo {} )  = let
      rtt = tcpi_rtt tcp_info
    in
      object [
      "rttvar" .= tcpi_rttvar tcp_info
      , "rtt" .= rtt
      , "rto" .= tcpi_rto tcp_info
      , "snd_cwnd" .= tcpi_snd_cwnd tcp_info
      , "snd_ssthresh" .= tcpi_snd_ssthresh tcp_info
      , "reordering"  .= tcpi_reordering tcp_info

      -- needs kernel patching
      -- , "fowd"  .= toJSON ( (fromIntegral rtt/2) :: Float)
      -- , "bowd"  .= toJSON ( (fromIntegral rtt/2) :: Float)

      , "fowd"  .= tcpi_fowd tcp_info
      , "bowd"  .= tcpi_bowd tcp_info


      -- , "total_retrans"  .= tcpi_total_retrans arg

      ]
  toJSON (TcpVegasInfo _ _ rtt minRtt) = object [ "rtt" .= toJSON (rtt :: Word32) ]
  toJSON (CongInfo cc) = object [ "cc" .= toJSON (cc) ]
  toJSON (DiagExtensionMemInfo wmem rmem _ _) = object [
      "wmem" .= toJSON ( wmem :: Word32 )
      , "rmem" .= toJSON ( rmem :: Word32 )
      ]
  toJSON _ = object []

-- TODO merge
--
instance ToJSON SockDiagMetrics where
  -- attributes of array
  -- foldr over array of extensions
  toJSON (SockDiagMetrics msg metrics) = let

      sf = connectionFromDiag msg
      tcpState = toEnum $ fromIntegral ( idiag_state msg) :: TcpState
      -- extensions = loadExtensionsFromAttributes attrs
      initialValue = object [
          "srcIp" .= toJSON (srcIp sf),
          "dstIp" .= toJSON (dstIp sf),
          "state" .= show tcpState
          ]
      fn x y = lodashMerge (toJSON x) y

    in
    -- (a -> b -> b) -> b -> t a -> b
    foldr fn initialValue metrics


-- |Updates the list of interfaces
-- should run in background
trackSystemInterfaces :: IO()
trackSystemInterfaces = do
  -- check routing information
  routingSock <- NLS.makeNLHandle (const $ pure ()) =<< NL.makeSocket
  let cb = NLS.NLCallback (pure ()) (handleAddr . runGet getGenPacket)
  NLS.nlPostMessage routingSock queryAddrs cb
  NLS.nlWaitCurrent routingSock
  dumpSystemInterfaces


-- | Remove ?
inspectIdiagAnswers :: [Packet SockDiagMsg] -> [Maybe SockDiagMetrics]
inspectIdiagAnswers packets =
  map inspectIDiagAnswer packets

{-| The MptcpSocket doesn't need to be global
-}
-- withFormatter :: GenericHandler Handle -> GenericHandler Handle
-- withFormatter handler = setFormatter handler formatter
--     -- http://hackage.haskell.org/packages/archive/hslogger/1.1.4/doc/html/System-Log-Formatter.html
--     where formatter = simpleLogFormatter "[$time $loggername $prio] $msg"

-- s'inspirer de
-- https://github.com/vdorr/linux-live-netinfo/blob/24ead3dd84d6847483aed206ec4b0e001bfade02/System/Linux/NetInfo.hs
main :: IO ()
main = do

  -- SETUP LOGGING (https://gist.github.com/ijt/1052896)
  myStreamHandler <- streamHandler stderr INFO
  -- let myStreamHandler' = withFormatter myStreamHandler
  -- let rootLog = rootLoggerName
  -- updateGlobalLogger rootLog (setLevel INFO)
  updateGlobalLogger "main" (setLevel DEBUG)

  infoM "main" "Parsing command line..."
  options <- execParser opts

  infoM "main" "Creating MPTCP netlink socket..."


  -- let jsonConn = toJSON $ MptcpConnection 32 Set.empty Set.empty Set.empty
  -- let objToMerge = object [ "toto" .= toJSON ("value" :: Value) ]
  -- let merged = lodashMerge jsonConn objToMerge
  -- let bs = Data.Aeson.encode $ merged
  -- putStrLn $ show bs

  -- add the socket too to an MVar ?
  (MptcpSocket sock  fid) <- makeMptcpSocket
  putMVar globalMptcpSock (MptcpSocket sock  fid)

  infoM "main" "Now Tracking system interfaces..."
  putMVar globalInterfaces Map.empty
  routeNl <- forkIO trackSystemInterfaces

  debugM "main" "socket created. MPTCP Family id "
  -- >> Prelude.print fid
  -- putStr "socket created. tcp_metrics Family id " >> print fidMetrics
  -- That's what I should use in fact !! (Word16, [CtrlAttrMcastGroup])
  -- (mid, mcastGroup ) <- getFamilyWithMulticasts sock mptcpGenlEvGrpName
  -- Each netlink family has a set of 32 multicast groups
  mcastMptcpGroups <- getMulticastGroups sock fid
  mapM_ Prelude.print mcastMptcpGroups

  let mptcpSocket = (MptcpSocket sock fid)
  let globalState = MyState mptcpSocket Map.empty options

  mapM_ (listenToEvents globalState) mcastMptcpGroups
  -- putStrLn $ " Groups: " ++ unwords ( map grpName mcastMptcpGroups )
  putStrLn "finished"