{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE CPP #-}

module Distribution.CurrentPackageDescription
  ( currentPackageDescription
  , getField
  ) where

import Prelude.Compat
import Distribution.PackageDescription
import Distribution.PackageDescription.Parse
import Distribution.Verbosity

import Data.List           (isSuffixOf)
import Language.Haskell.TH (stringE, runIO, Q, Exp)
import System.Directory    (getCurrentDirectory, getDirectoryContents)


getField :: (PackageDescription -> String) -> Q Exp
getField f = runIO currentPackageDescription >>= stringE . f

currentPackageDescription :: IO PackageDescription
currentPackageDescription = fmap packageDescription $ do
  dir <- getCurrentDirectory
  cs  <- cabalFiles dir
  case cs of
#if MIN_VERSION_base(4,10,0)
    (c:_) -> readGenericPackageDescription silent c
#else
    (c:_) -> readPackageDescription silent c
#endif
    []    -> error $ "Couldn't find a cabal file in the current working directory (" ++ dir ++ ")"

cabalFiles :: FilePath -> IO [FilePath]
cabalFiles dir = filter (".cabal" `isSuffixOf`) <$> getDirectoryContents dir