module Network.MPD.Core (
MonadMPD(..),
MPD, MPDError(..), ACKType(..), Response, Host, Port, Password,
withMPDEx,
getResponse, kill,
) where
import Network.MPD.Core.Class
import Network.MPD.Core.Error
import Control.Applicative (Applicative(..), (<$>))
import Control.Monad (ap, unless)
import Control.Monad.Error (ErrorT(..), MonadError(..))
import Control.Monad.Reader (ReaderT(..), ask)
import Control.Monad.State (StateT, MonadIO(..), put, get, evalStateT)
import qualified Data.Foldable as F
import Data.List (isPrefixOf)
import Network (PortID(..), withSocketsDo, connectTo)
import System.IO (Handle, hPutStrLn, hReady, hClose, hFlush)
import System.IO.Error (isEOFError)
import qualified System.IO.UTF8 as U
type Host = String
type Port = Integer
newtype MPD a =
MPD { runMPD :: ErrorT MPDError
(StateT (Maybe Handle)
(ReaderT (Host, Port, Password) IO)) a
} deriving (Functor, Monad, MonadIO, MonadError MPDError)
instance Applicative MPD where
(<*>) = ap
pure = return
instance MonadMPD MPD where
open = mpdOpen
close = mpdClose
send = mpdSend
getPassword = MPD $ ask >>= \(_,_,pw) -> return pw
type Response = Either MPDError
withMPDEx :: Host -> Port -> Password -> MPD a -> IO (Response a)
withMPDEx host port pw x = withSocketsDo $
runReaderT (evalStateT (runErrorT . runMPD $ open >> x) Nothing)
(host, port, pw)
mpdOpen :: MPD ()
mpdOpen = MPD $ do
(host, port, _) <- ask
runMPD close
handle <- liftIO (safeConnectTo host port)
put handle
F.forM_ handle (const $ runMPD checkConn >>= flip unless (runMPD close))
where
safeConnectTo host port =
(Just <$> connectTo host (PortNumber $ fromInteger port))
`catch` const (return Nothing)
checkConn =
isPrefixOf "OK MPD" <$> send ""
mpdClose :: MPD ()
mpdClose =
MPD $ get >>= F.mapM_ (liftIO . sendClose) >> put Nothing
where
sendClose handle =
(hPutStrLn handle "close" >> hReady handle >> hClose handle)
`catch` whenEOF (return ())
whenEOF result err
| isEOFError err = result
| otherwise = ioError err
mpdSend :: String -> MPD String
mpdSend str = send' `catchError` handler
where
handler TimedOut = mpdOpen >> send'
handler err = throwError err
send' = MPD $ get >>= maybe (throwError NoMPD) go
go handle = do
unless (null str) $
liftIO $ U.hPutStrLn handle str >> hFlush handle
liftIO ((Right <$> getLines handle []) `catch` (return . Left))
>>= either (\err -> if isEOFError err then
put Nothing >> throwError TimedOut
else liftIO (ioError err))
return
getLines handle acc = do
l <- U.hGetLine handle
if "OK" `isPrefixOf` l || "ACK" `isPrefixOf` l
then return . unlines $ reverse (l:acc)
else getLines handle (l:acc)
ignore :: (Monad m) => m a -> m ()
ignore x = x >> return ()
kill :: (MonadMPD m) => m ()
kill = ignore (send "kill") `catchError` cleanup
where
cleanup e = if e == TimedOut then close else throwError e
getResponse :: (MonadMPD m) => String -> m [String]
getResponse cmd = (send cmd >>= parseResponse) `catchError` sendpw
where
sendpw e@(ACK Auth _) = do
pw <- getPassword
if null pw then throwError e
else send ("password " ++ pw) >>= parseResponse
>> send cmd >>= parseResponse
sendpw e =
throwError e
parseResponse :: (MonadError MPDError m) => String -> m [String]
parseResponse s
| null xs = throwError $ NoMPD
| isPrefixOf "ACK" (head xs) = throwError $ parseAck s
| otherwise = return $ Prelude.takeWhile ("OK" /=) xs
where
xs = lines s
parseAck :: String -> MPDError
parseAck s = ACK ack msg
where
ack = case code of
2 -> InvalidArgument
3 -> InvalidPassword
4 -> Auth
5 -> UnknownCommand
50 -> FileNotFound
51 -> PlaylistMax
52 -> System
53 -> PlaylistLoad
54 -> Busy
55 -> NotPlaying
56 -> FileExists
_ -> UnknownACK
(code, _, msg) = splitAck s
splitAck :: String -> (Int, String, String)
splitAck s = (read code, cmd, msg)
where
(code, notCode) = between '[' '@' s
(cmd, notCmd) = between '{' '}' notCode
msg = drop 1 $ dropWhile (' ' ==) notCmd
between a b xs = let (_, y) = break (== a) xs
in break (== b) (drop 1 y)