module Logging (
  init_logging,
  log_debug,
  log_error,
  log_info,
  log_warning )
where

import System.Log.Handler.Simple ( GenericHandler )
import System.Log.Logger (
  Priority ( DEBUG, INFO ),
  debugM,
  errorM,
  infoM,
  rootLoggerName,
  setHandlers,
  setLevel,
  updateGlobalLogger,
  warningM )

log_debug :: String -> IO ()
log_debug = debugM rootLoggerName

log_error :: String -> IO ()
log_error = errorM rootLoggerName

log_info :: String -> IO ()
log_info = infoM rootLoggerName

log_warning :: String -> IO ()
log_warning = warningM rootLoggerName

init_logging :: Bool -> IO ()
init_logging use_syslog = do
  let max_level = if use_syslog then INFO else DEBUG
  -- We need to specify the type here; otherwise, setHandlers won't
  -- accept the empty list as an instance of [LogHandler a].
  let no_handlers = [] :: [GenericHandler a]
  -- Removes the default "echo to stdout" handler.
  updateGlobalLogger rootLoggerName (setLevel max_level
                                     . setHandlers no_handlers)