{-# LANGUAGE OverloadedStrings #-}
import qualified Data.ByteString.Lazy as BL
import Network.Nats
import Control.Concurrent

main :: IO ()
main = do
    -- Connect to the NATS server
    nats <- connect "nats://user:password@localhost:4222"
    -- Subscribe to channel "news", we do not use any queue group
    sid <- subscribe nats "news" Nothing $ 
            \_ _ msg _ ->    -- The parameters are (sid, subject, message, reply_subject)
                putStrLn $ show msg
    -- Publish a message (the message parameter is a lazy ByteString)
    publish nats "news" "I got news for you"
    -- Wait so that we can receive the message from the server
    threadDelay 1000000
    -- Unsubscribe from the channel
    unsubscribe nats sid
    -- Subscribe to a "gift" channel
    subscribe nats "gift" Nothing $ \_ _ msg mreply -> do
        putStrLn $ show msg
        case mreply of -- If the sender used a 'request' call, use this subject to send message back
            Nothing -> return ()
            Just reply -> publish nats reply "I've got a gift for you."
    -- Request/response communication with a "gift" channel
    reply <- request nats "gift" "Do you have anything for me?"
    putStrLn $ show reply