{-# LANGUAGE OverloadedStrings #-}
import Network.Wai
import Network.HTTP.Types
import Network.Wai.Handler.Warp (run)
import Database.MySQL.Simple
import Data.Pool (Pool, createPool, withResource)

newConn = connect defaultConnectInfo
    { connectHost = "db"
    , connectUser = "root"
    , connectPassword = "secret"
    , connectDatabase = "test" }

getPool = createPool newConn close 1 10 5

app :: Pool Connection -> Application
app pool _ respond = do
    withResource pool $ c -> query_ c "SELECT 1" :: IO [Only Int]
    respond $ responseLBS
        status200
        [("Content-Type", "text/plain")]
        "Hello, Web!"

main :: IO ()
main = do
    putStrLn $ "http://localhost:8080/"
    pool <- getPool
    run 8080 $ app $ pool