{-# LANGUAGE BlockArguments #-}
{-# LANGUAGE LambdaCase #-}

module ReduceCSpec where

import Control.Monad

import System.Directory
import System.FilePath
import Test.Hspec

import qualified Data.Text.Lazy as LazyText
import qualified Data.Text.Lazy.Encoding as LazyText

import Test.Hspec.Glitter

import qualified Language.C as C
import qualified Text.PrettyPrint as P

import Control.Monad.RTree (extract, iinputs, probe)
import Data.Bool
import Data.Functor
import Data.RPath
import qualified Language.C.System.GCC as C
import ReduceC
import System.Directory.Internal.Prelude (tryIOError)
import System.Process.Typed

spec :: Spec
spec = do
  cases <- runIO (listDirectory "test/cases")

  forM_ cases \cname -> do
    let cfrom = "test/cases" </> cname

    describe cfrom do
      c <- runIO $ parse cfrom

      let expected = "test/expected" </> dropExtensions cname
      onGlitterWith (expected </> "main.c") (\fp () -> render fp c) do
        it "should be valid" . foldMap $ \cf -> do
          validate cf

        it "should be parsed equally" . foldMap $ \cf -> do
          C.parseCFilePre cf >>= \case
            Left err -> fail (show err)
            Right c' -> c' $> () `shouldBe` c $> ()

      describe "reduction" do
        it "should extract itself" do
          fmap ($> ()) (extract $ defaultReduceC c) `shouldBe` Just (c $> ())

      onGlitterWith
        (expected </> "reduction/")
        ( \a () -> do
            _ <- tryIOError (removeDirectoryRecursive a)
            createDirectoryIfMissing True a
            forM_ (iinputs (defaultReduceC c)) \(i, c') -> do
              let rfile = expected </> "reduction" </> "r" <> debugShow i <.> "c"
              maybe (writeFile rfile "") (render rfile) c'
              let cofile = expected </> "reduction" </> "r" <> debugShow i <.> "choices"
              writeFile
                cofile
                ( unlines
                    . map (\(choice, (reason, pos)) -> bool "0" "1" choice <> " " <> reason <> " at " <> show pos)
                    . snd
                    $ probe (defaultReduceC c) i
                )
        )
        do
          it "should validate all reductions" . mapM_ $ \a -> do
            when (takeExtension a == ".c") do
              validate a

validate :: FilePath -> IO ()
validate fp = do
  (ec, _, stderr) <- readProcess (proc "clang" ["-o", "/dev/null", fp])
  case ec of
    ExitFailure _ ->
      expectationFailure $
        "could not validate "
          <> show fp
          <> "\n"
          <> LazyText.unpack (LazyText.decodeUtf8 stderr)
    ExitSuccess -> pure ()

render :: FilePath -> C.CTranslUnit -> IO ()
render cto c = do
  createDirectoryIfMissing True (takeDirectory cto)
  writeFile cto (P.render (C.pretty c) <> "\n")

parse :: FilePath -> IO C.CTranslUnit
parse cfrom = do
  cf <- C.parseCFile (C.newGCC "clang") Nothing [] cfrom
  case cf of
    Left err -> fail (show err)
    Right cf' -> pure cf'