{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE NoImplicitPrelude #-}
module Com.MusicMeetsComics.Server.Init where

import qualified Com.MusicMeetsComics.Server.Config as Config
import           Control.Concurrent (killThread)
import           Control.Exception (bracket)
import qualified Control.Monad.Metrics as M
import qualified Katip
import           Lens.Micro ((^.))
import           Network.Wai (Application, Middleware)
import           Network.Wai.Handler.Warp (run)
import           Network.Wai.Metrics (metrics, registerWaiMetrics)
import           Network.Wai.Middleware.Gzip
import           Protolude
import qualified System.IO as IO

-- | An action that creates a WAI 'Application' together with its resources,
--   runs it, and tears it down on exit
runApp :: (Config.Config -> Application) -> IO ()
runApp app = bracket Config.acquire shutdownApp jog
  where
    say = IO.hPutStrLn IO.stderr
    jog config = do
        say $ "hero"
        say $ "port: " ++ show (Config.configPort config)
        run (Config.configPort config) =<< initialize app config

-- | The 'initialize' function accepts the required environment information,
-- initializes the WAI 'Application' and returns it
initialize :: (Config.Config -> Application) -> Config.Config -> IO Application
initialize app cfg = do
  waiMetrics <- registerWaiMetrics (Config.configMetrics cfg ^. M.metricsStore)
  let logger = Config.setLogger (Config.configEnv cfg)
  -- generateJavaScript
  pure . logger . metrics waiMetrics . app $ cfg

compress :: Middleware
compress = gzip def { gzipFiles = GzipCompress }

-- | Takes care of cleaning up 'Config.Config' resources
shutdownApp :: Config.Config -> IO ()
shutdownApp cfg = do
  _ <- Katip.closeScribes (Config.configLogEnv cfg)
    -- Monad.Metrics does not provide a function to destroy metrics store
    -- so, it'll hopefully get torn down when async exception gets thrown
    -- at metrics server process
  killThread (Config.configEkgServer cfg)
  pure ()