module UnitTests
  ( unitTestFolder
  , compileTestFolder
  , compileVideoFolder
  ) where

import           Control.Exception
import qualified Data.ByteString.Lazy as LBS
import           Data.List            (sort)
import           Reanimate.Misc       (withTempDir, withTempFile)
import           System.Directory
import           System.Exit
import           System.FilePath
import           System.IO
import           System.Process
import           Test.Tasty
import           Test.Tasty.Golden
import           Test.Tasty.HUnit

unitTestFolder :: FilePath -> IO TestTree
unitTestFolder path = do
  files <- sort <$> getDirectoryContents path
  mbWDiff <- findExecutable "wdiff"
  let diff = case mbWDiff of
        Nothing -> ["diff", "--strip-trailing-cr"]
        Just wdiff -> [wdiff, "--no-common"]
  return $ testGroup "animate"
    [ goldenVsStringDiff file (\ref new -> diff ++ [ref, new]) fullPath (genGolden hsPath)
    | file <- files
    , let fullPath = path </> file
          hsPath = replaceExtension fullPath "hs"
    , takeExtension fullPath == ".golden"
    ]

genGolden :: FilePath -> IO LBS.ByteString
genGolden path = withTempDir $ \tmpDir -> withTempFile ".exe" $ \tmpExecutable -> do
  let ghcOpts = ["-rtsopts", "--make", "-O2"] ++
                ["-odir", tmpDir, "-hidir", tmpDir, "-o", tmpExecutable]
      runOpts = ["+RTS", "-M1G"]
  -- XXX: Check for errors.
  _ <- readProcessWithExitCode "stack" (["ghc","--", path] ++ ghcOpts) ""
  -- ret <- runCmd_ "stack" $ ["ghc", "--"] ++ ghcOptions tmpDir ++ [self, "-o", tmpExecutable]
  -- ["-rtsopts", "--make", "-threaded", "-O2"] ++
  -- ["-odir", tmpDir, "-hidir", tmpDir]
  (inh, outh, errh, _pid) <- runInteractiveProcess tmpExecutable (["test"] ++ runOpts)
    Nothing Nothing
  -- hSetBinaryMode outh True
  -- hSetNewlineMode outh universalNewlineMode
  hClose inh
  hClose errh
  LBS.hGetContents outh

compileTestFolder :: FilePath -> IO TestTree
compileTestFolder path = do
  files <- sort <$> getDirectoryContents path
  return $ testGroup "compile"
    [ testCase file $ do
        (ret, _stdout, err) <- readProcessWithExitCode "stack" (["ghc","--", fullPath] ++ ghcOpts) ""
        _ <- evaluate (length err)
        case ret of
          ExitFailure{} -> assertFailure $ "Failed to compile:\n" ++ err
          ExitSuccess   -> return ()
    | file <- files
    , let fullPath = path </> file
    , takeExtension file == ".hs" || takeExtension file == ".lhs"
    , notElem (replaceExtension file "golden") files
    ]
  where
    ghcOpts = ["-fno-code", "-O0", "-Werror", "-Wall"]

compileVideoFolder :: FilePath -> IO TestTree
compileVideoFolder path = do
  exist <- doesDirectoryExist path
  if exist
    then do
      files <- sort <$> getDirectoryContents path
      return $ testGroup "videos"
        [ testCase dir $ do
            (ret, _stdout, err) <- readProcessWithExitCode "stack" (["ghc","--", "-i"++path</>dir, fullPath] ++ ghcOpts) ""
            _ <- evaluate (length err)
            case ret of
              ExitFailure{} -> assertFailure $ "Failed to compile:\n" ++ err
              ExitSuccess   -> return ()
        | dir <- files
        , let fullPath = path </> dir </> dir <.> "hs"
        , dir /= "." && dir /= ".."
        ]
    else return $ testGroup "videos" []
  where
    ghcOpts = ["-fno-code", "-O0"]

--------------------------------------------------------------------------------
-- Helpers

-- findAnExecutable :: [String] -> IO (Maybe FilePath)
-- findAnExecutable [] = return Nothing
-- findAnExecutable (x:xs) = do
--   mbExec <- findExecutable x
--   case mbExec of
--     Just exec -> return (Just exec)
--     Nothing   -> findAnExecutable xs
--
-- readFileOptional :: FilePath -> IO String
-- readFileOptional path = do
--   hasFile <- doesFileExist path
--   if hasFile then readFile path else return ""
--
-- assertExitCode :: String -> ExitCode -> Assertion
-- assertExitCode _ ExitSuccess = return ()
-- assertExitCode msg (ExitFailure code) = assertFailure (msg ++ ", code: " ++ show code)
--
-- assertMaybe :: String -> Maybe a -> IO a
-- assertMaybe _ (Just a)  = return a
-- assertMaybe msg Nothing = assertFailure msg