module Sound.Tidal.Tempo where
import Data.Time (getCurrentTime, UTCTime, NominalDiffTime, diffUTCTime, addUTCTime)
import Data.Time.Clock.POSIX
import Control.Monad (forM_, forever, void)
import Control.Monad.IO.Class (liftIO)
import Control.Concurrent (forkIO, threadDelay)
import Control.Concurrent.MVar
import Control.Monad.Trans (liftIO)
import Data.Text (Text)
import qualified Data.Text as T
import qualified Data.Text.IO as T
import qualified Network.WebSockets as WS
import qualified Control.Exception as E
import qualified System.IO.Error as Error
import GHC.Conc.Sync (ThreadId)
import System.Environment (getEnv)
import Sound.Tidal.Utils
data Tempo = Tempo {at :: UTCTime, beat :: Double, cps :: Double, paused :: Bool, clockLatency :: Double}
type ClientState = [WS.Connection]
instance Eq WS.Connection
instance Show Tempo where
show x = show (at x) ++ "," ++ show (beat x) ++ "," ++ show (cps x) ++ "," ++ show (paused x) ++ "," ++ (show $ clockLatency x)
getLatency :: IO Double
getLatency = fmap (read) (getEnvDefault "0.04" "TIDAL_CLOCK_LATENCY")
getClockIp :: IO String
getClockIp = getEnvDefault "127.0.0.1" "TIDAL_TEMPO_IP"
getServerPort :: IO Int
getServerPort = fmap read (getEnvDefault "9160" "TIDAL_TEMPO_PORT")
readTempo :: String -> Tempo
readTempo x = Tempo (read a) (read b) (read c) (read d) (read e)
where (a:b:c:d:e:_) = wordsBy (== ',') x
logicalTime :: Tempo -> Double -> Double
logicalTime t b = changeT + timeDelta
where beatDelta = b (beat t)
timeDelta = beatDelta / (cps t)
changeT = realToFrac $ utcTimeToPOSIXSeconds $ at t
tempoMVar :: IO (MVar (Tempo))
tempoMVar = do now <- getCurrentTime
l <- getLatency
mv <- newMVar (Tempo now 0 0.5 False l)
forkIO $ clocked $ f mv
return mv
where f mv change _ = do swapMVar mv change
return ()
beatNow :: Tempo -> IO (Double)
beatNow t = do now <- getCurrentTime
let delta = realToFrac $ diffUTCTime now (at t)
let beatDelta = cps t * delta
return $ beat t + beatDelta
clientApp :: MVar Tempo -> MVar Double -> WS.ClientApp ()
clientApp mTempo mCps conn = do
liftIO $ forkIO $ sendCps conn mTempo mCps
forever loop
where
loop = do
msg <- WS.receiveData conn
let s = T.unpack msg
let tempo = readTempo $ s
liftIO $ tryTakeMVar mTempo
liftIO $ putMVar mTempo tempo
sendCps :: WS.Connection -> MVar Tempo -> MVar Double -> IO ()
sendCps conn mTempo mCps = forever $ do
cps <- takeMVar mCps
t <- readMVar mTempo
t' <- updateTempo t cps
WS.sendTextData conn (T.pack $ show t')
connectClient :: Bool -> String -> MVar Tempo -> MVar Double -> IO ()
connectClient secondTry ip mTempo mCps = do
let errMsg = "Failed to connect to tidal server. Try specifying a " ++
"different port (default is 9160) setting the " ++
"environment variable TIDAL_TEMPO_PORT"
serverPort <- getServerPort
WS.runClient ip serverPort "/tempo" (clientApp mTempo mCps) `E.catch`
\(_ :: E.SomeException) -> do
case secondTry of
True -> error errMsg
_ -> do
res <- E.try (void startServer)
case res of
Left (_ :: E.SomeException) -> error errMsg
Right _ -> do
threadDelay 500000
connectClient True ip mTempo mCps
runClient :: IO ((MVar Tempo, MVar Double))
runClient =
do clockip <- getClockIp
mTempo <- newEmptyMVar
mCps <- newEmptyMVar
forkIO $ connectClient False clockip mTempo mCps
return (mTempo, mCps)
cpsUtils :: IO ((Double -> IO (), IO (Rational)))
cpsUtils = do (mTempo, mCps) <- runClient
let cpsSetter b = putMVar mCps b
currentTime = do tempo <- readMVar mTempo
now <- beatNow tempo
return $ toRational now
return (cpsSetter, currentTime)
bpsUtils :: IO ((Double -> IO (), IO (Rational)))
bpsUtils = cpsUtils
cpsSetter :: IO (Double -> IO ())
cpsSetter = do (f, _) <- cpsUtils
return f
clocked :: (Tempo -> Int -> IO ()) -> IO ()
clocked = clockedTick 1
clockedTick :: Int -> (Tempo -> Int -> IO ()) -> IO ()
clockedTick tpb callback =
do (mTempo, mCps) <- runClient
t <- readMVar mTempo
now <- getCurrentTime
let delta = realToFrac $ diffUTCTime now (at t)
beatDelta = cps t * delta
nowBeat = beat t + beatDelta
nextTick = ceiling (nowBeat * (fromIntegral tpb))
loop mTempo nextTick
where loop mTempo tick =
do tempo <- readMVar mTempo
tick' <- doTick tempo tick
loop mTempo tick'
doTick tempo tick | paused tempo =
do let pause = 0.01
threadDelay $ floor (pause * 1000000)
return $ if cps tempo < 0 then 0 else tick
| otherwise =
do now <- getCurrentTime
let tps = (fromIntegral tpb) * cps tempo
delta = realToFrac $ diffUTCTime now (at tempo)
actualTick = ((fromIntegral tpb) * beat tempo) + (tps * delta)
tickDelta = (fromIntegral tick) actualTick
delay = tickDelta / tps
threadDelay $ floor (delay * 1000000)
callback tempo tick
return $ tick + 1
updateTempo :: Tempo -> Double -> IO (Tempo)
updateTempo t cps'
| paused t == True && cps' > 0 =
do now <- getCurrentTime
return $ t {at = addUTCTime (realToFrac $ clockLatency t) now, cps = cps', paused = False}
| otherwise =
do now <- getCurrentTime
let delta = realToFrac $ diffUTCTime now (at t)
beat' = (beat t) + ((cps t) * delta)
beat'' = if cps' < 0 then 0 else beat'
return $ t {at = now, beat = beat'', cps = cps', paused = (cps' <= 0)}
addClient client clients = client : clients
removeClient :: WS.Connection -> ClientState -> ClientState
removeClient client = filter (/= client)
broadcast :: Text -> ClientState -> IO ()
broadcast message clients = do
forM_ clients $ \conn -> WS.sendTextData conn $ message
startServer :: IO (ThreadId)
startServer = do
serverPort <- getServerPort
start <- getCurrentTime
l <- getLatency
tempoState <- newMVar (Tempo start 0 1 False l)
clientState <- newMVar []
forkIO $ WS.runServer "0.0.0.0" serverPort $ serverApp tempoState clientState
serverApp :: MVar Tempo -> MVar ClientState -> WS.ServerApp
serverApp tempoState clientState pending = do
conn <- WS.acceptRequest pending
tempo <- liftIO $ readMVar tempoState
liftIO $ WS.sendTextData conn $ T.pack $ show tempo
clients <- liftIO $ readMVar clientState
liftIO $ modifyMVar_ clientState $ \s -> return $ addClient conn s
serverLoop conn tempoState clientState
serverLoop :: WS.Connection -> MVar Tempo -> MVar ClientState -> IO ()
serverLoop conn tempoState clientState = E.handle catchDisconnect $
forever $ do
msg <- WS.receiveData conn
liftIO $ readMVar clientState >>= broadcast msg
where
catchDisconnect e = case E.fromException e of
Just WS.ConnectionClosed -> liftIO $ modifyMVar_ clientState $ \s -> do
let s' = removeClient conn s
return s'
_ -> return ()