------------------------------------------------------------------------------
-- |
-- Module: Xmobar.Text.Loop
-- Copyright: (c) 2022 Jose Antonio Ortega Ruiz
-- License: BSD3-style (see LICENSE)
--
-- Maintainer: jao@gnu.org
-- Stability: unstable
-- Portability: unportable
-- Created: Fri Jan 28, 2022 01:21
--
--
-- Text-only event loop
--
------------------------------------------------------------------------------

module Xmobar.Text.Loop (textLoop) where

import Prelude hiding (lookup)
import System.IO (hSetBuffering, stdin, stdout, BufferMode(LineBuffering))

import Control.Concurrent.STM

import Xmobar.System.Signal
import Xmobar.Config.Types (Config)
import Xmobar.Run.Loop (loop)
import Xmobar.Text.Output (initLoop, format)

-- | Starts the main event loop and threads
textLoop :: Config -> IO ()
textLoop :: Config -> IO ()
textLoop Config
conf = do
  Handle -> BufferMode -> IO ()
hSetBuffering Handle
stdin BufferMode
LineBuffering
  Handle -> BufferMode -> IO ()
hSetBuffering Handle
stdout BufferMode
LineBuffering
  Config -> IO ()
initLoop Config
conf
  Config -> LoopFunction -> IO ()
loop Config
conf (Config -> LoopFunction
eventLoop Config
conf)

-- | Continuously wait for a signal from a thread or a interrupt handler
eventLoop :: Config -> TMVar SignalType -> TVar [String] -> IO ()
eventLoop :: Config -> LoopFunction
eventLoop Config
cfg TMVar SignalType
signal TVar [String]
tv = do
  SignalType
typ <- STM SignalType -> IO SignalType
forall a. STM a -> IO a
atomically (STM SignalType -> IO SignalType)
-> STM SignalType -> IO SignalType
forall a b. (a -> b) -> a -> b
$ TMVar SignalType -> STM SignalType
forall a. TMVar a -> STM a
takeTMVar TMVar SignalType
signal
  case SignalType
typ of
    SignalType
Wakeup -> Config -> TVar [String] -> IO String
updateString Config
cfg TVar [String]
tv IO String -> (String -> IO ()) -> IO ()
forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= String -> IO ()
putStrLn IO () -> IO () -> IO ()
forall (m :: * -> *) a b. Monad m => m a -> m b -> m b
>> Config -> LoopFunction
eventLoop Config
cfg TMVar SignalType
signal TVar [String]
tv
    SignalType
_ -> Config -> LoopFunction
eventLoop Config
cfg TMVar SignalType
signal TVar [String]
tv

updateString :: Config -> TVar [String] -> IO String
updateString :: Config -> TVar [String] -> IO String
updateString Config
conf TVar [String]
v = do
  [String]
s <- TVar [String] -> IO [String]
forall a. TVar a -> IO a
readTVarIO TVar [String]
v
  Config -> String -> IO String
format Config
conf ([String] -> String
forall (t :: * -> *) a. Foldable t => t [a] -> [a]
concat [String]
s)