{-# LANGUAGE OverloadedStrings  #-}
{-# LANGUAGE RecordWildCards    #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# OPTIONS -fno-warn-orphans   #-}
module Main (main) where

import Prelude as P
import Control.Concurrent
import Control.Concurrent.Async
import Control.Concurrent.ParallelIO
import Control.Exception
import Control.Lens hiding (argument, (<.>))
import Control.Monad
import Control.Monad.Trans
import Data.Conduit as C
import Data.List as L
import Data.Maybe as L
import Data.Monoid
import Data.Text as T
import qualified Data.Text.IO as T
import Data.Text.Read as T
import Data.Version
import Network
import Network.URI
import Options.Applicative
import System.Exit
import System.FilePath
import System.Log
import System.Log.Logger
import Text.Read
import Text.PrettyPrint.Class

import Paths_bittorrent (version)
import Data.Torrent
import Data.Torrent.Bitfield as BF
import Data.Torrent.InfoHash
import Data.Torrent.Piece
import Data.Torrent.Layout
import Data.Torrent.Magnet hiding (Magnet)
import Network.BitTorrent.Core
import Network.BitTorrent.DHT.Session hiding (Options, options)
import Network.BitTorrent.DHT as DHT  hiding (Options)
import Network.BitTorrent.Exchange.Message
import Network.BitTorrent.Exchange.Connection hiding (Options)
import System.Torrent.Storage


{-----------------------------------------------------------------------
--  Dialogs
-----------------------------------------------------------------------}

instance Read URI where
  readsPrec _ = f . parseURI
    where
      f Nothing  = []
      f (Just u) = [(u, "")]

question :: Show a => Text -> Maybe a -> IO ()
question q defVal = do
  T.putStrLn q
  case defVal of
    Nothing -> return ()
    Just v  -> T.putStrLn $ "[default: " <> T.pack (show v) <> "]"

ask :: Read a => Text -> IO a
ask q = question q (Just True) >> getReply
  where
    getReply = do
      resp <- P.getLine
      maybe getReply return $ readMaybe resp

askMaybe :: Read a => Text -> IO (Maybe a)
askMaybe q = question q (Just False) >> getReply
  where
    getReply = do
      resp <- P.getLine
      if resp == []
        then return Nothing
        else maybe getReply return $ readMaybe resp

askURI :: IO URI
askURI = do
  s <- P.getLine
  case parseURI s of
    Nothing -> T.putStrLn "incorrect URI" >> askURI
    Just u  -> return u

askFreeform :: IO Text
askFreeform = do
  s <- T.getLine
  if T.null s
    then askFreeform
    else return s

askInRange :: Int -> Int -> IO Int
askInRange a b = do
  s <- T.getLine
  case T.decimal s of
    Left msg -> do
      P.putStrLn msg
      askInRange a b
    Right (i, _)
      | a <= i && i < b -> return i
      |     otherwise   -> do
        T.putStrLn "not in range "
        askInRange a b

askChoice :: [(Text, a)] -> IO a
askChoice kvs = do
  forM_ (L.zip [1 :: Int ..] $ L.map fst kvs) $ \(i, lbl) -> do
    T.putStrLn $ "  " <> T.pack (show i) <> ") " <> lbl
  T.putStrLn "Your choice?"
  n <- askInRange 1 (succ (L.length kvs))
  return $ snd (kvs !! pred n)

{-----------------------------------------------------------------------
--  Helpers
-----------------------------------------------------------------------}

torrentFile :: Parser FilePath
torrentFile = argument Just
    ( metavar "TORRENT_FILE_PATH"
   <> help    "A .torrent file"
    )

{-----------------------------------------------------------------------
--  Amend command - edit a field of torrent file
-----------------------------------------------------------------------}

data AmendOpts = AmendOpts FilePath
  deriving Show

amendInfo :: ParserInfo AmendOpts
amendInfo = info (helper <*> parser) modifier
  where
    modifier = progDesc "Edit info fields of existing torrent"
    parser   = AmendOpts <$> torrentFile

type Amend = Torrent -> Torrent

fields :: [(Text, IO Amend)]
fields = [ ("announce",      set announce     . Just <$> askURI)
         , ("comment",       set comment      . Just <$> askFreeform)
         , ("created by",    set createdBy    . Just <$> askFreeform)
         , ("publisher url", set publisherURL . Just <$> askURI)
         ]

askAmend :: IO Amend
askAmend = join $ T.putStrLn "Choose a field:" >> askChoice fields

amend :: AmendOpts -> IO ()
amend (AmendOpts tpath) = do
  t <- fromFile tpath
  a <- askAmend
  toFile tpath $ a t

{-----------------------------------------------------------------------
--  Check command -- validate content files using torrent file
-----------------------------------------------------------------------}
-- TODO progress bar

data CheckOpts = CheckOpts
  { checkTorrentPath :: FilePath -- ^ validation torrent file
  , checkContentPath :: FilePath -- ^ root dir for content files
  } deriving Show

checkInfo :: ParserInfo CheckOpts
checkInfo = info (helper <*> parser) modifier
  where
    modifier = progDesc "Validate integrity of torrent data"
        <> header   "append +RTS -N$NUMBER_OF_CORES -RTS for parallel execution"
    parser   = CheckOpts
      <$> torrentFile
      <*> argument Just
          ( metavar "CONTENT_DIR_PATH"
         <> value   "."
         <> help    "Content directory or a single file"
          )

validatePiece :: Storage -> PieceInfo -> PieceIx -> IO (Maybe PieceIx)
validatePiece s pinfo pix = do
  valid <- verifyPiece s pinfo pix
  if valid
    then do infoM "check" $ "valid piece "   ++ show pix
            return (Just pix)
    else do infoM "check" $ "invalid piece " ++ show pix
            return Nothing

validateStorage :: Storage -> PieceInfo -> IO Bitfield
validateStorage s pinfo = do
  infoM "check" "start storage validation"
  let total = totalPieces s
  pixs <- parallel $ L.map (validatePiece s pinfo) [0 .. total - 1]
  infoM "check" "storage validation finished"
  return $ fromList total $ L.catMaybes pixs

-- TODO use local thread pool
checkContent :: Storage -> PieceInfo -> IO ()
checkContent s pinfo = do
  invalids <- BF.complement <$> validateStorage s pinfo
  if BF.null invalids
    then noticeM "check" "all files are complete and valid"
    else do
      emergencyM "check" $ "there are some invalid pieces" ++ show invalids
      exitFailure

checkTorrent :: CheckOpts -> IO ()
checkTorrent CheckOpts {..} = do
  infoM "check" "openning torrent file..."
  InfoDict {..} <- tInfoDict <$> fromFile checkTorrentPath
  let layout = flatLayout checkContentPath idLayoutInfo
  infoM "check" "mapping content files..."
  withStorage ReadOnly (piPieceLength idPieceInfo) layout $ \ s -> do
    infoM "check" "files mapped"
    checkContent s idPieceInfo
    infoM "check" "unmapping files"

{-----------------------------------------------------------------------
--  Create command
-----------------------------------------------------------------------}
-- TODO progress bar
-- TODO multifile torrents
-- TODO interactive mode
-- TODO non interactive mode
-- TODO --ignore-dot-files
-- TODO --md5
-- TODO --piece-size

{-
createFlags :: Parser CreateFlags
createFlags = CreateFlags
    <$> optional (option
      ( long    "piece-size"
     <> short   's'
     <> metavar "SIZE"
     <> help    "Set size of torrent pieces"
      ))
    <*> switch
      ( long    "md5"
     <> short   '5'
     <> help    "Include md5 hash of each file"
      )
    <*> switch
      ( long    "ignore-dot-files"
     <> short   'd'
     <> help    "Do not include .* files"
      )


createOpts :: Parser CreateOpts
createOpts = CreateOpts
    <$> argument Just
        ( metavar "PATH"
       <> help    "Content directory or a single file"
        )
    <*> optional (argument Just
        ( metavar "FILE"
       <> help    "Place for the output .torrent file"
        ))
    <*> createFlags

createInfo :: ParserInfo CreateOpts
createInfo = info (helper <*> createOpts) modifier
  where
    modifier = progDesc "Make a new .torrent file"
-}

{-----------------------------------------------------------------------
--  Magnet command -- print magnet link for given torrent file
-----------------------------------------------------------------------}

data MagnetOpts = MagnetOpts
  { magnetFile :: FilePath -- ^ path to torrent file
  , detailed   :: Bool     -- ^ whether to append additional uri params
  } deriving Show

magnetInfo :: ParserInfo MagnetOpts
magnetInfo = info (helper <*> parser) modifier
  where
    modifier = progDesc "Print magnet link"
    parser   = MagnetOpts
      <$> torrentFile
      <*> switch ( long "detailed" )

magnet :: MagnetOpts -> IO ()
magnet MagnetOpts {..} = print . magnetLink =<< fromFile magnetFile
  where
    magnetLink = if detailed then detailedMagnet else simpleMagnet

{-----------------------------------------------------------------------
--  Show command - print torrent file information
-----------------------------------------------------------------------}

data ShowOpts = ShowOpts
  { showPath     :: FilePath -- ^ torrent file to inspect;
  , infoHashOnly :: Bool     -- ^ omit everything except infohash.
  } deriving Show

showInfo :: ParserInfo ShowOpts
showInfo = info (helper <*> parser) modifier
  where
    modifier = progDesc "Print .torrent file metadata"
    parser   = ShowOpts
      <$> torrentFile
      <*> switch
          ( long "infohash"
         <> help "Show only hash of the torrent info part"
          )

showTorrent :: ShowOpts -> Torrent -> ShowS
showTorrent ShowOpts {..} torrent
  | infoHashOnly = shows $ idInfoHash (tInfoDict torrent)
  |   otherwise  = shows $ pretty torrent

putTorrent :: ShowOpts -> IO ()
putTorrent opts @ ShowOpts {..} = do
    torrent <- fromFile showPath `onException` putStrLn msg
    putStrLn $ showTorrent opts torrent []
  where
    msg = "Torrent file is either invalid or do not exist"

{-----------------------------------------------------------------------
--  Get command - fetch torrent by infohash
-----------------------------------------------------------------------}

data GetOpts = GetOpts
  { topic    :: InfoHash
  , servPort :: PortNumber
  , bootNode :: NodeAddr IPv4
  , buckets  :: Int
  } deriving Show

instance Read PortNumber where
  readsPrec i s = [ (toEnum a, t) | (a, t) <- readsPrec i s]

paramsParser :: Parser GetOpts
paramsParser = GetOpts
  <$> argument readMaybe
             (metavar "SHA1"     <> help "infohash of torrent file")
  <*> option (long    "port"     <> short 'p'
           <> value   7000       <> showDefault
           <> metavar "NUM"      <> help "port number to bind"
             )
  <*> option (long    "boot"     <> short 'b'
           <> metavar "NODE"     <> help "bootstrap node address"
             )
  <*> option (long    "bucket"   <> short 'n'
           <> value 2            <> showDefault
           <> metavar "NUM"      <> help "number of buckets to maintain"
             )

getInfo :: ParserInfo GetOpts
getInfo = info (helper <*> paramsParser)
   ( fullDesc
  <> progDesc "Get torrent file by infohash"
  <> header   "get torrent file by infohash"
   )

exchangeTorrent :: InfoHash -> PeerAddr IP -> IO InfoDict
exchangeTorrent ih addr = do
  pid <- genPeerId
  var <- newEmptyMVar
  let hs = Handshake def (toCaps [ExtExtended]) ih pid
  chan <- newChan
  connectWire () hs addr (toCaps [ExtMetadata]) chan $ do
    infodict <- undefined -- getMetadata
    liftIO $ putMVar var infodict
  takeMVar var

exchangeConc :: InfoHash -> [PeerAddr IP] -> IO (Maybe InfoDict)
exchangeConc ih peers = do
  workers <- forM peers $ async . exchangeTorrent ih
  (_, result) <- waitAnyCatchCancel workers
  return $ either (const Nothing) Just result

sinkInfoDict :: InfoHash -> Sink [PeerAddr IPv4] (DHT ip) InfoDict
sinkInfoDict ih = do
  m <- await
  case m of
    Nothing -> liftIO $ throwIO $ userError "impossible: end of peer stream"
    Just peers -> do
      minfodict <- liftIO $ exchangeConc ih (fmap IPv4 <$> peers)
      maybe (sinkInfoDict ih) return minfodict

 -- TODO add tNodes, tCreated, etc?
getTorrent :: GetOpts -> IO ()
getTorrent GetOpts {..} = do
  infoM "get" "starting..."
  dht (def { optBucketCount = buckets }) (NodeAddr "0.0.0.0" servPort) $ do
    bootstrap [bootNode]
    liftIO $ infoM "get" "searching for peers..."
    infodict <- DHT.lookup topic $$ sinkInfoDict topic
    liftIO $ infoM "get" "saving torrent file..."
    liftIO $ toFile (show topic <.> torrentExt) $ nullTorrent infodict
  infoM "get" "done"

{-----------------------------------------------------------------------
--  Command
-----------------------------------------------------------------------}

data Command
  = Amend  AmendOpts
  | Check  CheckOpts
--  | Create CreateOpts
  | Get    GetOpts
  | Magnet MagnetOpts
  | Show   ShowOpts
    deriving Show

commandOpts :: Parser Command
commandOpts = subparser $ mconcat
    [ command "amend"  (Amend  <$> amendInfo)
    , command "check"  (Check  <$> checkInfo)
--    , command "create" (Create <$> createInfo)
    , command "get"    (Get    <$> getInfo)
    , command "magnet" (Magnet <$> magnetInfo)
    , command "show"   (Show   <$> showInfo)
    ]

{-----------------------------------------------------------------------
--  Global Options
-----------------------------------------------------------------------}

data GlobalOpts = GlobalOpts
  { verbosity   :: Priority
  } deriving Show

deriving instance Enum    Priority
deriving instance Bounded Priority

priorities :: [Priority]
priorities = [minBound..maxBound]

defaultPriority :: Priority
defaultPriority = WARNING

verbosityOpts :: Parser Priority
verbosityOpts = verbosityP <|> verboseP <|> quietP
  where
    verbosityP = option
      ( long    "verbosity"
     <> metavar "LEVEL"
     <> help   ("Set verbosity level\n"
             ++ "Possible values are " ++ show priorities)
      )

    verboseP = flag defaultPriority INFO
      ( long    "verbose"
     <> short   'v'
     <> help    "Verbose mode"
      )

    quietP = flag defaultPriority CRITICAL
      ( long    "quiet"
     <> short   'q'
     <> help    "Silent mode"
      )


globalOpts :: Parser GlobalOpts
globalOpts = GlobalOpts <$> verbosityOpts

data Options = Options
  { cmdOpts  :: Command
  , globOpts :: GlobalOpts
  } deriving Show

options :: Parser Options
options = Options <$> commandOpts <*> globalOpts

versioner :: String -> Version -> Parser (a -> a)
versioner prog ver = nullOption $ mconcat
    [ long  "version"
    , help  "Show program version and exit"
    , value id
    , metavar ""
    , hidden
    , reader $ const $ undefined -- Left $ ErrorMsg versionStr
    ]
  where
    versionStr = prog ++ " version " ++ showVersion ver

parserInfo :: ParserInfo Options
parserInfo = info parser modifier
  where
    parser   = helper <*> versioner "mktorrent" version <*> options
    modifier = header synopsis <> progDesc description <> fullDesc
    synopsis    = "Torrent management utility"
    description = "" -- TODO

{-----------------------------------------------------------------------
--  Dispatch
-----------------------------------------------------------------------}

run :: Command -> IO ()
run (Amend  opts) = amend opts
run (Check  opts) = checkTorrent opts
--run (Create opts) = createTorrent opts
run (Get    opts) = getTorrent opts
run (Magnet opts) = magnet opts
run (Show   opts) = putTorrent opts

prepare :: GlobalOpts -> IO ()
prepare GlobalOpts {..} = do
  updateGlobalLogger rootLoggerName (setLevel verbosity)

main :: IO ()
main = do
  Options {..} <- execParser parserInfo
  prepare globOpts
  run cmdOpts