Prelude.hs

{-# LANGUAGE CPP #-}
{-# LANGUAGE OverloadedStrings #-}

-- | Common functions
module Podenv.Prelude
  ( module Relude,
    foldM,
    lookup,
    getEnv,
    orDie,
    mayFail,

    -- * io
    readFileM,
    hPutStrLn,

    -- * base env

#if !MIN_VERSION_relude(1,0,0)
    getArgs,
    lookupEnv,
#endif
    getExecutablePath,

    -- * xdg
    getCacheDir,
    getConfigDir,
    getDataDir,

    -- * directory
    createDirectoryIfMissing,
    getCurrentDirectory,
    doesFileExist,
    doesPathExist,
    doesSymlinkExist,
    pathIsSymbolicLink,
    findExecutable,
    (</>),
    takeFileName,
    takeDirectory,
    hasTrailingPathSeparator,
    listDirectory,

    -- * posix
    UserID,
    getRealUserID,

    -- * lens
    Lens',
    (^.),
    (.~),
    (?~),
    (%~),
    setWhenNothing,
  )
where

import qualified Control.Exception
import Control.Monad (foldM)
import qualified Data.Text.IO
import Lens.Family (ASetter, set, (%~), (.~), (^.))
import Relude
import Relude.Extra.Lens (Lens')
import System.Directory
import System.Environment
import System.FilePath.Posix (hasTrailingPathSeparator, takeDirectory, takeFileName, (</>))
import System.IO (hPutStrLn)
import qualified System.Posix.Files
import System.Posix.Types (UserID)
import System.Posix.User (getRealUserID)

orDie :: Maybe a -> Text -> Either Text a
orDie (Just a) _ = Right a
orDie Nothing e = Left e

mayFail :: Either Text a -> IO a
mayFail (Right a) = pure a
mayFail (Left msg) = hPutStrLn stderr ("Error: " <> toString msg) >> exitFailure >> fail "over"

(?~) :: ASetter s t a (Maybe b) -> b -> s -> t
l ?~ b = set l (Just b)

setWhenNothing :: ASetter s t (Maybe b) (Maybe b) -> b -> s -> t
l `setWhenNothing` b = l %~ maybe (Just b) Just

getCacheDir :: IO FilePath
getCacheDir = getXdgDirectory XdgCache "podenv"

getDataDir :: IO FilePath
getDataDir = getXdgDirectory XdgData "podenv"

getConfigDir :: IO FilePath
getConfigDir = getXdgDirectory XdgConfig "podenv"

readFileM :: FilePath -> IO Text
readFileM fp' = do
  exist <- liftIO $ doesFileExist fp'
  if exist
    then liftIO $ Data.Text.IO.readFile fp'
    else pure ""

doesSymlinkExist :: FilePath -> IO Bool
doesSymlinkExist fp =
  either (const False) (const True) <$> checkFp
  where
    checkFp :: IO (Either Control.Exception.SomeException FilePath)
    checkFp = Control.Exception.try $ System.Posix.Files.readSymbolicLink fp