{-# LANGUAGE CPP                      #-}
{-# LANGUAGE LambdaCase               #-}
{-# LANGUAGE NamedFieldPuns           #-}
{-# LANGUAGE NondecreasingIndentation #-}
{-# LANGUAGE ViewPatterns             #-}
module ToxToXMPP
    ( forkAccountWatcher
    , JabberClients
    , PerClient
    , initPerClient
    , toxQSearch
    , toxAnnounceInterval
    , xmppToTox
    , toxToXmpp
    , interweave
    ) where

import Data.Conduit                 as C
import qualified Data.Conduit.List  as CL
import Data.XML.Types               as XML
import EventUtil
import Network.Tox.Crypto.Transport as Tox
import Network.Tox.Handshake        (HandshakeParams (..))
import Util                         (unsplitJID)
import XMPPServer                   as XMPP

import Announcer
import Announcer.Tox
import Connection
import Network.QueryResponse
import Network.Tox.DHT.Handlers (nodeSearch, nodesOfInterest)
-- import Control.Concurrent
import Control.Concurrent.STM
import Control.Monad
import Crypto.Tox
import qualified Data.HashMap.Strict         as HashMap
import Data.Maybe
import qualified Data.Set                    as Set
import qualified Data.Text                   as T
import Data.Time.Clock.POSIX
import Network.Address
import Network.Kademlia.Search
import qualified Network.Tox                 as Tox
import Network.Tox.ContactInfo               as Tox
import qualified Network.Tox.Crypto.Handlers as Tox
         ;import Network.Tox.Crypto.Handlers (UponCookie (..))
-- import qualified Network.Tox.DHT.Handlers    as Tox
import ClientState
import Data.Bits
import Data.Function
import qualified Data.Map                    as Map
import Data.Text                             (Text)
import Data.Word
import qualified Network.Kademlia.Routing    as R
import Network.Tox
import Network.Tox.DHT.Handlers
import qualified Network.Tox.DHT.Transport   as Tox
         ;import Network.Tox.DHT.Transport   (FriendRequest (..), dhtpk)
import Network.Tox.NodeId
import qualified Network.Tox.Onion.Handlers  as Tox
import qualified Network.Tox.Onion.Transport as Tox
         ;import Network.Tox.Onion.Transport (OnionData (..))
import Presence
import Text.Read
import XMPPServer                            (ClientAddress)
#ifdef THREAD_DEBUG
import Control.Concurrent.Lifted.Instrument
#else
import Control.Concurrent.Lifted
import GHC.Conc                  (labelThread)
#endif
import DPut
import Nesting
import qualified Network.Tox.DHT.Handlers

xmppToTox :: Conduit XML.Event IO Tox.CryptoMessage
xmppToTox = doNestingXML $ do
    eventBeginDocument <- await
    streamTag <- await
    fix $ \loop -> do
    e <- nextElement
    -- dput DPut.XMan $ "xmppToTox: " ++ show e
    --
    -- (yield e >> awaitForever yield) $$ prettyPrint "xmpp->Tox"
    -- prettyPrint
    loop

toxToXmpp :: Monad m => SockAddr -> PublicKey -> Text -> Conduit Tox.CryptoMessage m XML.Event
toxToXmpp laddr me theirhost = do
    CL.sourceList $ XMPP.greet' "jabber:server" theirhost
    let me_u = T.pack $ show (key2id me)
    awaitForever $ \toxmsg -> do
        xmppInstantMessage "jabber:server"
            (Just theirhost)      -- /from/
            (Just $ unsplitJID (Just me_u,T.pack (show laddr),Nothing)) -- /to/ should match local address of this node.
            (T.pack $ show $ msgID toxmsg)

xmppInstantMessage :: Monad m => Text -> Maybe Text -> Maybe Text -> Text -> ConduitM i Event m ()
xmppInstantMessage namespace mfrom mto text = do
    let ns n = n { nameNamespace = Just namespace }
    C.yield $ EventBeginElement (ns "message")
               (  maybe id (\t->(attr "from" t:)) mfrom
                $ maybe id (\t->(attr "to" t:)) mto
                $ [attr "type" "normal" ] )
    C.yield $   EventBeginElement (ns "body") []
    C.yield $     EventContent $ ContentText text
    C.yield $   EventEndElement (ns "body")
    C.yield $   EventBeginElement "{http://jabber.org/protocol/xhtml-im}html" []
    C.yield $     EventBeginElement "{http://www.w3.org/1999/xhtml}body" []
    C.yield $        EventBeginElement "{http://www.w3.org/1999/xhtml}p"
                       [ attr "style" "font-weight:bold; color:red" ]
    C.yield $          EventContent $ ContentText text
    C.yield $        EventEndElement "{http://www.w3.org/1999/xhtml}p"
    C.yield $     EventEndElement "{http://www.w3.org/1999/xhtml}body"
    C.yield $   EventEndElement "{http://jabber.org/protocol/xhtml-im}html"
    C.yield $ EventEndElement (ns "message")

key2jid :: Word32 -> PublicKey -> Text
key2jid nospam key = T.pack $ show $ NoSpamId nsp key
 where
    nsp = NoSpam nospam (Just sum)
    sum = nlo `xor` nhi `xor` xorsum key
    nlo = fromIntegral (0x0FFFF .&. nospam) :: Word16
    nhi = fromIntegral (0x0FFFF .&. (nospam `shiftR` 16)) :: Word16

type JabberClients = Map.Map ClientAddress PerClient

data PerClient = PerClient
    { pcDeliveredFRs :: TVar (Set.Set Tox.FriendRequest)
    }

initPerClient :: STM PerClient
initPerClient = do
    frs <- newTVar Set.empty
    return PerClient
        { pcDeliveredFRs = frs
        }

data ToxToXMPP = ToxToXMPP
    { txAnnouncer :: Announcer
    , txAccount   :: Account JabberClients
    , txPresence  :: PresenceState
    , txTox       :: Tox JabberClients
    }

default_nospam :: Word32
default_nospam = 0x6a7a27fc -- big-endian base64: anon/A==

nodeinfoStaleTime  :: POSIXTime
nodeinfoStaleTime = 600

nodeinfoSearchInterval :: POSIXTime
nodeinfoSearchInterval = 15

data Awaiting v = Since POSIXTime
data Acquired v = At POSIXTime v
data Moot v     = Moot

data NNS a b c = NNS { -- NetcryptoNegotiationState
  sessionDesired  :: Bool,
  theirPublicKey  :: a Tox.DHTPublicKey,
  theirAddress    :: b NodeInfo,
  theirCookie     :: c (Tox.Cookie Encrypted),
  sessionIsActive :: Bool
}

data NS
  = Stage1 (NNS Moot Moot Moot)
  | Stage2 (NNS Awaiting Moot Moot)
  | Stage3 (NNS Acquired Awaiting Moot)
  | Stage4 (NNS Acquired Acquired Awaiting)
  | Stage5 (NNS Acquired Acquired Acquired)

gotDhtPubkey :: Tox.DHTPublicKey -> ToxToXMPP -> PublicKey -> IO ()
gotDhtPubkey theirDhtKey tx theirKey = do
  contact <- atomically $ getContact theirKey (txAccount tx) >>= mapM (readTVar . contactLastSeenAddr)
  forM_ contact $ \lastSeen -> do
    case lastSeen of
      Nothing -> doSearch
      Just (tm, _) -> do
        now <- getPOSIXTime
        when (now - tm > nodeinfoStaleTime) doSearch
  where
    tox :: Tox JabberClients
    tox = txTox tx

    myPublicKey = toPublic $ userSecret (txAccount tx)
    me = key2id myPublicKey

    doSearch = do
      let akey = akeyConnect (txAnnouncer tx) me theirKey
      atomically $ registerNodeCallback (toxRouting tox) (nic akey)
      scheduleSearch (txAnnouncer tx) akey meth theirDhtKey

    target :: NodeId
    target = key2id $ dhtpk theirDhtKey

    meth :: SearchMethod Tox.DHTPublicKey
    meth =
      SearchMethod
      { sSearch       = nodeSearch (toxDHT tox) (nodesOfInterest $ toxRouting tox)
      , sNearestNodes = nearNodes tox
      , sTarget       = target
      , sInterval     = nodeinfoSearchInterval
      , sWithResult   = \r sr -> return ()
      }
    nic akey =
      NodeInfoCallback
      { interestingNodeId = target
      , listenerId        = 2
      , observedAddress   = observe akey
      , rumoredAddress    = assume akey
      }

    assume :: AnnounceKey -> POSIXTime -> SockAddr -> NodeInfo -> STM ()
    assume akey time addr ni =
      tput XNodeinfoSearch $ show ("rumor", akey, time, addr, ni)

    observe :: AnnounceKey -> POSIXTime -> NodeInfo -> STM ()
    observe akey time ni@(nodeAddr -> addr) = do
      tput XNodeinfoSearch $ show ("observation", akey, time, addr)
      setContactAddr time theirKey ni (txAccount tx)

gotAddr :: NodeInfo -> ToxToXMPP -> PublicKey -> IO ()
gotAddr ni@(nodeAddr -> addr) tx theirKey = do
  dhtkey <- (fmap.fmap) snd $
            fmap join $
            atomically $
            traverse readTVar =<< fmap contactKeyPacket <$> getContact theirKey (txAccount tx)
  forM_ dhtkey $ gotAddr' ni tx theirKey

gotAddr' :: NodeInfo -> ToxToXMPP -> PublicKey -> Tox.DHTPublicKey -> IO ()
gotAddr' ni@(nodeAddr -> addr) tx theirKey theirDhtKey = atomically blee

  where
    myPublicKey = toPublic $ userSecret (txAccount tx)
    me          = key2id myPublicKey
    akey        = akeyConnect (txAnnouncer tx) me theirKey

    blee = do
      scheduleImmediately (txAnnouncer tx) akey $
        ScheduledItem $ getCookie ni (activeSesh addr) (getContact theirKey (txAccount tx))

    tox :: Tox JabberClients
    tox = txTox tx

    byAddr :: TVar (Map.Map SockAddr Tox.NetCryptoSession)
    byAddr = Tox.netCryptoSessions (toxCryptoSessions tox)

    crypto = Tox.transportCrypto $ toxCryptoSessions tox

    readNcVar :: (Tox.NetCryptoSession -> TVar b) -> SockAddr -> STM (Maybe b)
    readNcVar v addr = traverse readTVar =<< fmap v . Map.lookup addr <$> readTVar byAddr

    chillSesh :: SockAddr -> STM (Maybe (Status Tox.ToxProgress))
    chillSesh = readNcVar Tox.ncState

    activeSesh :: SockAddr -> STM Bool
    activeSesh a = chillSesh a >>= return . \case
      Just Established -> True
      _                -> False

    readCookie :: SockAddr -> STM (Maybe (UponCookie (Tox.Cookie Encrypted)))
    readCookie = readNcVar Tox.ncCookie
    readCookie' :: SockAddr -> STM (Maybe (Tox.Cookie Encrypted))
    readCookie' = fmap join . (fmap.fmap) Tox.toMaybe . readCookie

    client :: Network.Tox.DHT.Handlers.Client
    client = toxDHT tox

    getCookie
      :: NodeInfo
      -> STM Bool
      -> STM (Maybe Contact)
      -> Announcer
      -> AnnounceKey
      -> POSIXTime
      -> STM (IO ())
    getCookie ni isActive getC ann akey now = getCookieAgain
      where
        getCookieAgain = do
          tput XNodeinfoSearch $ show ("getCookieAgain", akey)
          mbContact  <- getC
          case mbContact of
            Nothing      -> return $ return ()
            Just contact -> do
              active <- isActive
              return $ when (not active) getCookieIO

        callRealShakeHands = realShakeHands (userSecret (txAccount tx)) theirKey (dhtpk theirDhtKey) (toxCryptoSessions tox) (nodeAddr ni)

        reschedule n f = scheduleRel ann akey f n
        reschedule' n f = reschedule n (ScheduledItem $ \_ _ now -> f now)

        cookieMaxAge = 60 * 5

        getCookieIO :: IO ()
        getCookieIO = do
          dput XUnused "getCookieIO - entered"
          cookieRequest crypto client myPublicKey ni >>= \case
            Nothing -> atomically $ reschedule' 5 (const getCookieAgain)
            Just cookie -> do
              void $ callRealShakeHands cookie
              cookieCreationStamp <- getPOSIXTime
              let shaker :: POSIXTime -> STM (IO ())
                  shaker now = do
                    active <- isActive
                    if (active)
                      then return $ return ()
                      else if (now > cookieCreationStamp + cookieMaxAge)
                             then return $
                                  dput XUnused "getCookieIO/shaker - cookie expired" >>
                                  getCookieIO
                             else do
                               reschedule' 5 shaker
                               return . void $ callRealShakeHands cookie
              atomically $ reschedule' 5 shaker

realShakeHands :: SecretKey -> PublicKey -> PublicKey -> Tox.NetCryptoSessions -> SockAddr -> Tox.Cookie Encrypted -> IO Bool
realShakeHands myseckey theirpubkey theirDhtKey allsessions saddr cookie = do
  dput XUnused "realShakeHands"
  let hp =
        HParam
        { hpOtherCookie = cookie
        , hpMySecretKey = myseckey
        , hpCookieRemotePubkey = theirpubkey
        , hpCookieRemoteDhtkey = theirDhtKey
        , hpTheirBaseNonce = Nothing
        , hpTheirSessionKeyPublic = Nothing
        }
  newsession <- generateSecretKey
  timestamp <- getPOSIXTime
  (myhandshake, ioAction) <-
    atomically $
    Tox.freshCryptoSession allsessions saddr newsession timestamp hp
  ioAction
  -- send handshake
  isJust <$> forM myhandshake (Tox.sendHandshake allsessions saddr)

dispatch :: ToxToXMPP -> ContactEvent -> IO ()
dispatch tx (SessionEstablished theirKey)                    = stopConnecting tx theirKey
dispatch tx (SessionTerminated theirKey)                     = startConnecting tx theirKey
dispatch tx (AddrChange   theirKey saddr)                    = gotAddr saddr tx theirKey
dispatch tx (PolicyChange theirkey TryingToConnect         ) = startConnecting tx theirkey
dispatch tx (PolicyChange theirkey policy                  ) = stopConnecting tx theirkey
dispatch tx (OnionRouted  theirKey (OnionDHTPublicKey pkey)) = gotDhtPubkey pkey tx theirKey
dispatch tx (OnionRouted  theirkey (OnionFriendRequest fr) ) = do
    let ToxToXMPP { txAnnouncer = acr
                  , txAccount   = acnt
                  , txPresence  = st } = tx
    k2c <- atomically $ do
        refs <- readTVar (accountExtra acnt)
        k2c <- Map.intersectionWith (,) refs <$> readTVar (ckeyToChan st)
        clients <- readTVar (clients st)
        return $ Map.intersectionWith (,) k2c clients
    -- TODO: Below we're using a hard coded default as their jabber user id.
    -- This isn't the right thing, but we don't know their user-id.  Perhaps
    -- there should be a way to parse it out of the friend request text.  Maybe
    -- after a zero-termination, or as visible text (nospam:...).
    let theirjid = key2jid default_nospam theirkey
    forM_ k2c $ \((PerClient{pcDeliveredFRs},conn),client) -> do
        alreadyDelivered <- atomically $ do
            frs <- readTVar pcDeliveredFRs
            writeTVar pcDeliveredFRs $ Set.insert fr frs
            return $ Set.member fr frs
        when (not alreadyDelivered) $ do
        self <- localJID (clientUser client) (clientProfile client) (clientResource client)
        ask <- presenceSolicitation theirjid self
        -- TODO Send friend-request text as an instant message or at least
        -- embed it in the stanza as a <status> element.
        sendModifiedStanzaToClient ask (connChan conn)

interweave :: [a] -> [a] -> [a]
interweave []     ys = ys
interweave (x:xs) ys = x : interweave ys xs

akeyDHTKeyShare :: Announcer -> NodeId -> PublicKey -> AnnounceKey
akeyDHTKeyShare announcer me them =
    packAnnounceKey announcer $ "dhtkey:" ++ (take 8 $ show me) ++ ":" ++ show (key2id them)

akeyConnect :: Announcer -> NodeId -> PublicKey -> AnnounceKey
akeyConnect announcer me them =
    packAnnounceKey announcer $ "connect:" ++ (take 8 $ show me) ++ ":" ++ show (key2id them)


-- | Returns a list of nospam values to use for friend requests to send to a
-- remote peer.  This list is non-empty only when it is desirable to send
-- friend requests.
checkSoliciting :: PresenceState -> PublicKey -> PublicKey -> Contact -> IO [NoSpam]
checkSoliciting presence me them contact = do
    let theirhost = T.pack $ show (key2id them) ++ ".tox"
        myhost = T.pack $ show (key2id me) ++ ".tox"
    xs <- getBuddiesAndSolicited presence $ \h -> do
        -- TODO: /h/ matches hostname?
        return $ T.toLower h == T.toLower theirhost
    return $ do
        (is_buddy,their_u,my_uid,xmpp_client_profile) <- xs
        guard $ xmpp_client_profile == myhost
        NoSpamId nospam _ <- case fmap T.unpack $ their_u of
            Just ('$':_)     -> maybeToList $ readMaybe $ T.unpack $ unsplitJID (their_u,theirhost,Nothing)
            Just ('0':'x':_) -> maybeToList $ readMaybe $ T.unpack $ unsplitJID (their_u,theirhost,Nothing)
            _                -> maybeToList $ readMaybe $ T.unpack $ key2jid default_nospam them
        return nospam

nearNodes :: Tox extra -> NodeId -> STM [NodeInfo]
nearNodes tox nid = do
  bkts4 <- readTVar $ routing4 $ toxRouting tox
  bkts6 <- readTVar $ routing6 $ toxRouting tox
  let nss =
        map
          (R.kclosest (searchSpace (toxQSearch tox)) searchK nid)
          [bkts4, bkts6]
  return $ foldr interweave [] nss

startConnecting0 :: ToxToXMPP -> PublicKey -> Contact -> IO ()
startConnecting0 tx them contact = do
        dput XMan $ "START CONNECTING " ++ show (key2id them)
        let ToxToXMPP { txTox       = tox
                      , txAnnouncer = announcer
                      , txAccount   = acnt     } = tx
        let nearNodes nid = do
                bkts4 <- readTVar $ routing4 $ toxRouting tox
                bkts6 <- readTVar $ routing6 $ toxRouting tox
                let nss = map (R.kclosest (searchSpace (toxQSearch tox)) searchK nid)
                              [bkts4,bkts6]
                return $ foldr interweave [] nss
        wanted <- atomically $ (==Just TryingToConnect) <$> readTVar (contactPolicy contact)
        let mypub = toPublic $ userSecret acnt
            me  = key2id mypub
        soliciting <- checkSoliciting (txPresence tx) mypub them contact
        when wanted $ do
            akey <- return $ akeyDHTKeyShare announcer me them
                    -- We send this packet every 30 seconds if there is more
                    -- than one peer (in the 8) that says they our friend is
                    -- announced on them. This packet can also be sent through
                    -- the DHT module as a DHT request packet (see DHT) if we
                    -- know the DHT public key of the friend and are looking
                    -- for them in the DHT but have not connected to them yet.
                    -- 30 second is a reasonable timeout to not flood the
                    -- network with too many packets while making sure the
                    -- other will eventually receive the packet. Since packets
                    -- are sent through every peer that knows the friend,
                    -- resending it right away without waiting has a high
                    -- likelihood of failure as the chances of packet loss
                    -- happening to all (up to to 8) packets sent is low.
                    --
            let meth = SearchMethod (toxQSearch tox) onResult nearNodes (key2id them) 30
                 where
                  onResult theirkey rendezvous = do
                    dkey <- Tox.getContactInfo tox
                    let tr    = Tox.toxToRoute tox
                        route = Tox.AnnouncedRendezvous theirkey rendezvous
                    dput XMan $ unwords [ take 8 (show $ key2id mypub) ++ ":"
                                        , "Sending my DHT-key"
                                        , show (key2id $ Tox.dhtpk dkey)
                                        , "to"
                                        , show (key2id theirkey)
                                        , "via"
                                        , show (Tox.rendezvousNode rendezvous)
                                        ]
                    sendMessage tr route (mypub,Tox.OnionDHTPublicKey dkey)
                    forM_ soliciting $ \cksum@(NoSpam nospam _)-> do
                        dput XMan $ unwords [ take 8 (show $ key2id mypub) ++ ":"
                                            , "Sending friend-request"
                                            , "with nospam"
                                            , "(" ++ nospam64 cksum ++ "," ++nospam16 cksum ++ ")"
                                            , "to"
                                            , show (key2id theirkey)
                                            , "via"
                                            , show (Tox.rendezvousNode rendezvous)
                                            ]
                        let fr = FriendRequest
                                    { friendNoSpam      = nospam
                                    , friendRequestText = "XMPP friend request"
                                    }
                        sendMessage tr route (mypub,Tox.OnionFriendRequest fr)
            scheduleSearch announcer akey meth them

startConnecting :: ToxToXMPP -> PublicKey -> IO ()
startConnecting tx them = do
    mc <- atomically $ HashMap.lookup (key2id them)
                        <$> readTVar (contacts $ txAccount tx)
    forM_ mc $ startConnecting0 tx them


stopConnecting :: ToxToXMPP -> PublicKey -> IO ()
stopConnecting ToxToXMPP{txAnnouncer=announcer,txAccount=acnt} them = do
    dput XMan $ "STOP CONNECTING " ++ show (key2id them)
    let pub  = toPublic $ userSecret acnt
        me   = key2id pub
        akey = akeyDHTKeyShare announcer me them
    cancel announcer akey

forkAccountWatcher :: Account JabberClients -> Tox JabberClients -> PresenceState -> Announcer -> IO ThreadId
forkAccountWatcher acc tox st announcer = forkIO $ do
    myThreadId >>= flip labelThread ("tox-xmpp:"
                                      ++ show (key2id $ toPublic $ userSecret acc))
    (chan,cs) <- atomically $ do
                chan <- dupTChan $ eventChan acc -- duplicate broadcast channel for reading.
                contacts <- readTVar (contacts acc)
                return (chan,contacts)
    let tx = ToxToXMPP { txAnnouncer = announcer
                       , txAccount   = acc
                       , txPresence  = st
                       , txTox       = tox
                       }
    forM_ (HashMap.toList cs) $ \(them,c) -> do
        startConnecting0 tx (id2key them) c

    -- Loop endlessly until accountExtra is null.
    fix $ \loop -> do
    mev <- atomically $
            (Just <$> readTChan chan)
            `orElse` do
                refs <- readTVar $ accountExtra acc
                check $ Map.null refs
                return Nothing

    forM_ mev $ \ev -> dispatch tx ev >> loop

    cs <- atomically $ readTVar (contacts acc)
    forM_ (HashMap.toList cs) $ \(them,c) -> do
        stopConnecting tx (id2key them)


toxQSearch :: Tox extra -> Search Tox.NodeId (IP, PortNumber) Nonce32 Tox.NodeInfo Tox.Rendezvous
toxQSearch tox = Tox.toxidSearch (Tox.onionTimeout tox) (Tox.toxCryptoKeys tox) (Tox.toxOnion tox)

toxAnnounceInterval :: POSIXTime
toxAnnounceInterval = 15