{-# LANGUAGE DuplicateRecordFields, OverloadedLists #-}
{-# OPTIONS_GHC -Wall #-}
module Data.Language.Ruby
  ( module Data.Language.Ruby.AST
  , parse
  , parseFile
  ) where

import Data.Aeson (eitherDecode)
import Data.ByteString.Lazy (ByteString)
import Data.Language.Ruby.AST
import Frelude
import System.IO (hFlush)
import System.IO.Temp (withSystemTempFile)
import System.Process (readProcess)
import qualified Data.ByteString.Lazy.Char8 as ByteString

decodeFail :: MonadFail m => FromJSON a => ByteString -> m a
decodeFail s = case eitherDecode s of
  Left err -> Frelude.fail err
  Right a -> pure a

runRubyParseFile :: FilePath -> IO String
runRubyParseFile p = sh "ruby-parse" ["--emit-json", "--25", p]

runRubyParse :: ByteString -> IO String
runRubyParse s = withSystemTempFile "rubyhs" $ \p h -> do
  ByteString.hPut h s
  hFlush h
  runRubyParseFile p

sh :: String -> [String] -> IO String
sh cmd a = readProcess cmd a mempty

parseFile :: FromJSON a => FilePath -> IO a
parseFile = runRubyParseFile >=> decodeFail . ByteString.pack

parse :: FromJSON a => ByteString -> IO a
parse = runRubyParse >=> decodeFail . ByteString.pack