{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE TypeApplications #-}

-- |
-- Module      :  ELynx.Tools.Logger
-- Description :  Monad logger utility functions
-- Copyright   :  (c) Dominik Schrempf 2021
-- License     :  GPL-3.0-or-later
--
-- Maintainer  :  dominik.schrempf@gmail.com
-- Stability   :  unstable
-- Portability :  portable
--
-- Creation date: Fri Sep  6 14:43:19 2019.
module ELynx.Tools.Logger
  ( -- * Logger
    logNewSection,
    eLynxWrapper,
  )
where

import Control.Monad.Base (liftBase)
import Control.Monad.IO.Class
import Control.Monad.Logger
import Control.Monad.Trans.Control (MonadBaseControl)
import Control.Monad.Trans.Reader (ReaderT (runReaderT))
import qualified Data.ByteString.Char8 as BS
import Data.Text
import ELynx.Tools.InputOutput (openFile')
import ELynx.Tools.Reproduction
import System.IO
import System.Random.MWC

-- | Unified way of creating a new section in the log.
logNewSection :: MonadLogger m => Text -> m ()
logNewSection s = $(logInfo) $ "== " <> s

-- | The 'ReaderT' and 'LoggingT' wrapper for ELynx. Prints a header and a
-- footer, logs to 'stderr' if no file is provided. Initializes the seed if none
-- is provided. If a log file is provided, log to the file and to 'stderr'.
eLynxWrapper ::
  forall a b.
  (Eq a, Show a, Reproducible a, ToJSON a) =>
  Arguments a ->
  (Arguments a -> Arguments b) ->
  ELynx b () ->
  IO ()
eLynxWrapper args f worker = do
  -- Arguments.
  let gArgs = global args
      lArgs = local args
  let lvl = toLogLevel $ verbosity gArgs
      rd = forceReanalysis gArgs
      outBn = outFileBaseName gArgs
      logFile = (++ ".log") <$> outBn
  runELynxLoggingT lvl rd logFile $ do
    -- Header.
    h <- liftIO $ logHeader (cmdName @a) (cmdDsc @a)
    $(logInfo) $ pack $ h ++ "\n"
    -- Fix seed.
    lArgs' <- case getSeed lArgs of
      Nothing -> return lArgs
      Just Random -> do
        -- XXX: Have to go via a generator here, since creation of seed is not
        -- supported.
        g <- liftIO createSystemRandom
        s <- liftIO $ fromSeed <$> save g
        $(logInfo) $ pack $ "Seed: random; set to " <> show s <> "."
        return $ setSeed lArgs s
      Just (Fixed s) -> do
        $(logInfo) $ pack $ "Seed: " <> show s <> "."
        return lArgs
    let args' = Arguments gArgs lArgs'
    -- Run the worker with the fixed seed.
    runReaderT worker $ f args'
    -- Reproduction file.
    case (writeElynxFile gArgs, outBn) of
      (False, _) ->
        $(logInfo)
          "No elynx file option --- skip writing ELynx file for reproducible runs."
      (True, Nothing) ->
        $(logInfo)
          "No output file given --- skip writing ELynx file for reproducible runs."
      (True, Just bn) -> do
        $(logInfo) "Write ELynx reproduction file."
        liftIO $ writeReproduction bn args'
    -- Footer.
    ftr <- liftIO logFooter
    $(logInfo) $ pack ftr

runELynxLoggingT ::
  (MonadBaseControl IO m, MonadIO m) =>
  LogLevel ->
  Force ->
  Maybe FilePath ->
  LoggingT m a ->
  m a
runELynxLoggingT lvl _ Nothing =
  runELynxStderrLoggingT . filterLogger (\_ l -> l >= lvl)
runELynxLoggingT lvl frc (Just fn) =
  runELynxFileLoggingT frc fn . filterLogger (\_ l -> l >= lvl)

runELynxFileLoggingT ::
  MonadBaseControl IO m => Force -> FilePath -> LoggingT m a -> m a
runELynxFileLoggingT frc fp logger = do
  h <- liftBase $ openFile' frc fp WriteMode
  liftBase (hSetBuffering h LineBuffering)
  r <- runLoggingT logger (output2H stderr h)
  liftBase (hClose h)
  return r

runELynxStderrLoggingT :: MonadIO m => LoggingT m a -> m a
runELynxStderrLoggingT = (`runLoggingT` output stderr)

output :: Handle -> Loc -> LogSource -> LogLevel -> LogStr -> IO ()
output h _ _ _ msg = BS.hPutStrLn h ls where ls = fromLogStr msg

output2H :: Handle -> Handle -> Loc -> LogSource -> LogLevel -> LogStr -> IO ()
output2H h1 h2 _ _ _ msg = do
  BS.hPutStrLn h1 ls
  BS.hPutStrLn h2 ls
  where
    ls = fromLogStr msg