{-# LANGUAGE LambdaCase #-}

module XMonad.Stockholm.Shutdown
    ( sendShutdownEvent
    , handleShutdownEvent
    , shutdown
    )
  where

import Control.Monad
import Data.Monoid
import System.Exit (exitSuccess)
import XMonad

sendShutdownEvent :: IO ()
sendShutdownEvent = do
    dpy <- openDisplay ""
    rw <- rootWindow dpy $ defaultScreen dpy
    a <- internAtom dpy "XMONAD_SHUTDOWN" False
    allocaXEvent $ \e -> do
        setEventType e clientMessage
        setClientMessageEvent e rw a 32 0 currentTime
        sendEvent dpy rw False structureNotifyMask e
    sync dpy False

handleShutdownEvent :: Event -> X All
handleShutdownEvent = \case
  ClientMessageEvent { ev_message_type = mt } -> do
    c <- (mt ==) <$> getAtom "XMONAD_SHUTDOWN"
    when c shutdown
    return (All c)
  _ ->
    return (All True)

shutdown :: X ()
shutdown = do
  broadcastMessage ReleaseResources
  writeStateToFile
  _ <- io $ do
    exitSuccess
  return ()