{-# LANGUAGE FlexibleInstances          #-}
{-# LANGUAGE TypeSynonymInstances       #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE TemplateHaskell            #-}
module Network.BitTorrent.Client
       ( -- * Options
         Options (..)

         -- * Client session
       , Client

         -- ** Session data
       , clientPeerId
       , clientListenerPort
       , allowedExtensions

         -- ** Session initialization
       , LogFun
       , newClient
       , closeClient
       , withClient
       , simpleClient

         -- * BitTorrent monad
       , MonadBitTorrent (..)
       , BitTorrent
       , runBitTorrent
       , getClient

         -- * Handle
       , Handle
       , handleTopic
       , handleTrackers
       , handleExchange

         -- ** Construction
       , TorrentSource (..)
       , closeHandle

         -- ** Query
       , getHandle
       , getIndex

         -- ** Management
       , start
       , pause
       , stop
       ) where

import Control.Applicative
import Control.Exception
import Control.Concurrent
import Control.Concurrent.Chan.Split as CS
import Control.Monad.Logger
import Control.Monad.Trans
import Control.Monad.Trans.Resource

import Data.Default
import Data.HashMap.Strict as HM
import Data.Text
import Network

import           Data.Torrent
import           Network.Address
import           Network.BitTorrent.Client.Types
import           Network.BitTorrent.Client.Handle
import           Network.BitTorrent.DHT      as DHT      hiding (Options)
import           Network.BitTorrent.Tracker  as Tracker  hiding (Options)
import           Network.BitTorrent.Exchange as Exchange hiding (Options)
import qualified Network.BitTorrent.Exchange as Exchange (Options(..))


data Options = Options
  { optFingerprint :: Fingerprint
  , optName        :: Text
  , optPort        :: PortNumber
  , optExtensions  :: [Extension]
  , optNodeAddr    :: NodeAddr IPv4
  , optBootNode    :: Maybe (NodeAddr IPv4)
  }

instance Default Options where
  def = Options
    { optFingerprint = def
    , optName        = "hs-bittorrent"
    , optPort        = 6882
    , optExtensions  = []
    , optNodeAddr    = "0.0.0.0:6882"
    , optBootNode    = Nothing
    }

exchangeOptions :: PeerId -> Options -> Exchange.Options
exchangeOptions pid Options {..} = Exchange.Options
  { optPeerAddr = PeerAddr (Just pid) (peerHost def) optPort
  , optBacklog  = optBacklog def
  }

connHandler :: MVar (HashMap InfoHash Handle) -> Exchange.Handler
connHandler tmap ih = do
  m <- readMVar tmap
  case HM.lookup ih m of
    Nothing            -> error "torrent not found"
    Just (Handle {..}) -> return handleExchange

initClient :: Options -> LogFun -> ResIO Client
initClient opts @ Options {..} logFun = do
  pid  <- liftIO genPeerId
  tmap <- liftIO $ newMVar HM.empty

  let peerInfo = PeerInfo pid Nothing optPort
  let mkTracker = Tracker.newManager def peerInfo
  (_, tmgr) <- allocate mkTracker Tracker.closeManager

  let mkEx = Exchange.newManager (exchangeOptions pid opts) (connHandler tmap)
  (_, emgr) <- allocate mkEx Exchange.closeManager

  let mkNode = DHT.newNode defaultHandlers def optNodeAddr logFun Nothing
  (_, node) <- allocate mkNode DHT.closeNode

  resourceMap <- getInternalState
  eventStream <- liftIO newSendPort

  return Client
    { clientPeerId       = pid
    , clientListenerPort = optPort
    , allowedExtensions  = toCaps optExtensions
    , clientResources    = resourceMap
    , trackerManager     = tmgr
    , exchangeManager    = emgr
    , clientNode         = node
    , clientTorrents     = tmap
    , clientLogger       = logFun
    , clientEvents       = eventStream
    }

newClient :: Options -> LogFun -> IO Client
newClient opts logFun = do
  s <- createInternalState
  runInternalState (initClient opts logFun) s
    `onException` closeInternalState s

closeClient :: Client -> IO ()
closeClient Client {..} = closeInternalState clientResources

withClient :: Options -> LogFun -> (Client -> IO a) -> IO a
withClient opts lf action = bracket (newClient opts lf) closeClient action

-- do not perform IO in 'initClient', do it in the 'boot'
--boot :: BitTorrent ()
--boot = do
--  Options {..} <- asks options
--  liftDHT $ bootstrap (maybeToList optBootNode)

-- | Run bittorrent client with default options and log to @stderr@.
--
--   For testing purposes only.
--
simpleClient :: BitTorrent () -> IO ()
simpleClient m = do
  runStderrLoggingT $ LoggingT $ \ logger -> do
    withClient def logger (`runBitTorrent` m)

{-----------------------------------------------------------------------
--  Torrent identifiers
-----------------------------------------------------------------------}

class TorrentSource s where
  openHandle :: FilePath -> s -> BitTorrent Handle

instance TorrentSource InfoHash where
  openHandle path ih = openMagnet path (nullMagnet ih)
  {-# INLINE openHandle #-}

instance TorrentSource Magnet where
  openHandle = openMagnet
  {-# INLINE openHandle #-}

instance TorrentSource InfoDict where
  openHandle path dict = openTorrent path (nullTorrent dict)
  {-# INLINE openHandle #-}

instance TorrentSource Torrent where
  openHandle = openTorrent
  {-# INLINE openHandle #-}

instance TorrentSource FilePath where
  openHandle contentDir torrentPath = do
    t <- liftIO $ fromFile torrentPath
    openTorrent contentDir t
  {-# INLINE openHandle #-}

getIndex :: BitTorrent [Handle]
getIndex = do
  Client {..} <- getClient
  elems <$> liftIO (readMVar clientTorrents)