1 files changed, 154 insertions, 0 deletions
diff --git a/src/Xmobar/Plugins/Kraken.hs b/src/Xmobar/Plugins/Kraken.hs
new file mode 100644
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--- /dev/null
+++ b/src/Xmobar/Plugins/Kraken.hs
@@ -0,0 +1,154 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE DeriveGeneric #-}
+
+module Xmobar.Plugins.Kraken (Kraken(..)) where
+
+import Control.Concurrent
+import Control.Monad (forever, mzero, void)
+import Data.Aeson
+import Data.Aeson.Types (Parser, typeMismatch)
+import Data.List (sort)
+import Data.Text (Text, pack, unpack)
+import GHC.Generics
+import System.IO (hPutStrLn, stderr)
+import Text.Read (readMaybe)
+import Xmobar.Run.Exec(Exec(..))
+import Network.WebSockets (ClientApp, receiveData, sendTextData)
+import Wuss (runSecureClient)
+
+import qualified Data.HashMap.Lazy as HML (lookup)
+import qualified Data.Map as Map
+import qualified Data.Vector as V
+
+data Kraken = Kraken [String] String
+  deriving (Read,Show)
+
+instance Exec Kraken where
+  alias (Kraken _ a) = a
+  start (Kraken ps _) cb = do
+    mvar <- newEmptyMVar 
+    forkIO $ runSecureClient "ws.kraken.com" 443 "/" $ wsClientApp ps mvar
+    let loop mv p = do
+         v <- takeMVar mv
+         let g = Map.insert (unpack $ fst v) (snd v) p
+         cb (display g)
+         loop mv g
+
+    loop mvar (Map.fromList $ zip ps (repeat 0.0))
+
+    where
+      display :: Map.Map String Double -> String 
+      display m = unwords $ sort $ map (\x -> fst x ++ ": " ++ show (snd x)) $ Map.toList m
+
+wsClientApp :: [String] -> MVar (Text, Double)  -> ClientApp ()
+wsClientApp ps mvar connection = do
+  sendTextData connection (encode (Subscribe { event = "subscribe", pair = map pack ps, subscription = Subscription { name = "ticker" }} ))
+  void . forever $ do
+    message <- receiveData connection
+    case (eitherDecode message :: Either String Message) of
+      Right m ->
+        case m of
+          TickerMessage _ ti _ tp  -> putMVar mvar (tp, askPrice $ ask ti)
+          _ -> return ()
+      Left e -> hPutStrLn stderr e
+
+data Ask = Ask {
+    askPrice :: Double
+  , askWholeLotVolume :: Int
+  , askLotVolume :: Double
+  } deriving Show
+
+parseDoubleString :: Value -> Parser Double
+parseDoubleString v = do
+  j <- parseJSON v
+  case readMaybe j of
+    Just num -> return num
+    Nothing -> typeMismatch "Double inside a String" v
+
+instance FromJSON Ask where 
+  parseJSON (Array v)
+    | V.length v == 3 = do
+      p <- parseDoubleString $ v V.! 0
+      w <- parseJSON $ v V.! 1
+      l <- parseDoubleString $ v V.! 2
+      return $ Ask { askPrice = p, askWholeLotVolume = w, askLotVolume = l }
+    | otherwise = mzero
+  parseJSON nonArray = typeMismatch "Array" nonArray
+
+data Bid = Bid {
+    bidPrice :: Double
+  , bidWholeLotVolume :: Int
+  , bidLotVolume :: Double
+  } deriving Show
+
+instance FromJSON Bid where 
+  parseJSON (Array v)
+    | V.length v == 3 = do
+      p <- parseDoubleString $ v V.! 0
+      w <- parseJSON $ v V.! 1
+      l <- parseDoubleString $ v V.! 2
+      return $ Bid { bidPrice = p, bidWholeLotVolume = w, bidLotVolume = l }
+    | otherwise = mzero
+  parseJSON nonArray = typeMismatch "Array" nonArray
+
+data Close = Close {
+    closePrice :: Double
+  , closeLotVolume :: Double
+  } deriving Show
+
+instance FromJSON Close where 
+  parseJSON (Array v)
+    | V.length v == 2 = do
+      p <- parseDoubleString $ v V.! 0
+      l <- parseDoubleString $ v V.! 1
+      return $ Close { closePrice= p, closeLotVolume = l }
+    | otherwise = mzero
+  parseJSON nonArray = typeMismatch "Array" nonArray
+
+data TickerInformation = TickerInformation {
+    ask :: Ask
+  , bid :: Bid
+  , close :: Close
+  } deriving Show
+
+instance FromJSON TickerInformation where 
+  parseJSON = withObject "P" $ \v -> TickerInformation
+    <$> v .: "a"
+    <*> v .: "b"
+    <*> v .: "c"
+  
+data Message =
+    Heartbeat
+  | TickerMessage { channelId :: Int, tickerInformation :: TickerInformation, channelName :: Text, tickerPair :: Text }
+  | SubscriptionStatus { channelName :: Text, status :: Text, subscriptionPair :: Text }
+  | SystemStatus { connectionId :: Integer, status :: Text, version :: Text }
+  | UnrecognizedMessage String
+  deriving Show
+
+newtype Subscription = Subscription { name :: Text } deriving (Generic, Show)
+instance ToJSON Subscription where
+  toEncoding = genericToEncoding defaultOptions
+
+data Subscribe = Subscribe { event :: Text, pair :: [Text], subscription :: Subscription } deriving (Generic, Show)
+instance ToJSON Subscribe where
+  toEncoding = genericToEncoding defaultOptions
+
+instance FromJSON Message where
+  parseJSON (Object o) = case HML.lookup (pack "event") o of
+    Just (String "heartbeat") -> pure Heartbeat
+    Just (String "systemStatus") -> systemStatus o
+    Just (String "subscriptionStatus") -> subscriptionStatus o
+    Just eventType -> pure $ UnrecognizedMessage $ "Unrecognized event type " ++ show eventType
+    Nothing -> pure $ UnrecognizedMessage "Missing event"
+    where
+      systemStatus obj = SystemStatus <$> obj .: "connectionID" <*> obj .: "status" <*> obj .: "version"
+      subscriptionStatus obj = SubscriptionStatus <$> obj .: "channelName" <*> obj .: "status" <*> obj .: "pair"
+  parseJSON (Array a)
+    | V.length a == 4 = do
+      cId   <- parseJSON $ a V.! 0
+      info  <- parseJSON $ a V.! 1
+      cName <- parseJSON $ a V.! 2
+      p     <- parseJSON $ a V.! 3
+      pure $ TickerMessage { channelId = cId, tickerInformation = info, channelName = cName, tickerPair = p }
+    | otherwise = mzero
+  parseJSON v = typeMismatch "Object or Array" v