{-# LANGUAGE DataKinds #-}
{-# LANGUAGE DoAndIfThenElse #-}
{-# LANGUAGE TupleSections #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE OverloadedStrings #-}

module TestCompiler where

-- Failing tests can specify the kind of error that should be thrown with a
-- @shouldFailWith declaration. For example:
--
--   "-- @shouldFailWith TypesDoNotUnify"
--
-- will cause the test to fail unless that module fails to compile with exactly
-- one TypesDoNotUnify error.
--
-- If a module is expected to produce multiple type errors, then use multiple
-- @shouldFailWith lines; for example:
--
--   -- @shouldFailWith TypesDoNotUnify
--   -- @shouldFailWith TypesDoNotUnify
--   -- @shouldFailWith TransitiveExportError

import Prelude ()
import Prelude.Compat

import qualified Language.PureScript as P

import Data.Char (isSpace)
import Data.Function (on)
import Data.List (sort, stripPrefix, intercalate, groupBy, sortBy, minimumBy)
import Data.Maybe (mapMaybe)
import Data.Time.Clock (UTCTime())
import qualified Data.Text as T
import Data.Tuple (swap)

import qualified Data.Map as M

import Control.Monad
import Control.Arrow ((***), (>>>))

import Control.Monad.Reader
import Control.Monad.Trans.Except

import System.Exit
import System.Process hiding (cwd)
import System.FilePath
import System.Directory
import System.IO
import System.IO.UTF8
import qualified System.FilePath.Glob as Glob

import TestUtils
import Test.Tasty
import Test.Tasty.Hspec

main :: IO TestTree
main = testSpec "compiler" spec

spec :: Spec
spec = do

  (supportModules, supportExterns, supportForeigns, passingTestCases, warningTestCases, failingTestCases) <- runIO $ do
    cwd <- getCurrentDirectory
    let passing = cwd </> "tests" </> "purs" </> "passing"
    let warning = cwd </> "tests" </> "purs" </> "warning"
    let failing = cwd </> "tests" </> "purs" </> "failing"
    passingFiles <- getTestFiles passing <$> testGlob passing
    warningFiles <- getTestFiles warning <$> testGlob warning
    failingFiles <- getTestFiles failing <$> testGlob failing
    ms <- getSupportModuleTuples
    let modules = map snd ms
    supportExterns <- runExceptT $ do
      foreigns <- inferForeignModules ms
      externs <- ExceptT . fmap fst . runTest $ P.make (makeActions modules foreigns) modules
      return (externs, foreigns)
    case supportExterns of
      Left errs -> fail (P.prettyPrintMultipleErrors P.defaultPPEOptions errs)
      Right (externs, foreigns) -> return (modules, externs, foreigns, passingFiles, warningFiles, failingFiles)

  outputFile <- runIO $ do
    tmp <- getTemporaryDirectory
    createDirectoryIfMissing False (tmp </> logpath)
    openFile (tmp </> logpath </> logfile) WriteMode

  context "Passing examples" $
    forM_ passingTestCases $ \testPurs ->
      it ("'" <> takeFileName (getTestMain testPurs) <> "' should compile and run without error") $
        assertCompiles supportModules supportExterns supportForeigns testPurs outputFile

  context "Warning examples" $
    forM_ warningTestCases $ \testPurs -> do
      let mainPath = getTestMain testPurs
      expectedWarnings <- runIO $ getShouldWarnWith mainPath
      it ("'" <> takeFileName mainPath <> "' should compile with warning(s) '" <> intercalate "', '" expectedWarnings <> "'") $
        assertCompilesWithWarnings supportModules supportExterns supportForeigns testPurs expectedWarnings

  context "Failing examples" $
    forM_ failingTestCases $ \testPurs -> do
      let mainPath = getTestMain testPurs
      expectedFailures <- runIO $ getShouldFailWith mainPath
      it ("'" <> takeFileName mainPath <> "' should fail with '" <> intercalate "', '" expectedFailures <> "'") $
        assertDoesNotCompile supportModules supportExterns supportForeigns testPurs expectedFailures

  where

  -- A glob for all purs and js files within a test directory
  testGlob :: FilePath -> IO [FilePath]
  testGlob = Glob.globDir1 (Glob.compile "**/*.purs")

  -- Groups the test files so that a top-level file can have dependencies in a
  -- subdirectory of the same name. The inner tuple contains a list of the
  -- .purs files and the .js files for the test case.
  getTestFiles :: FilePath -> [FilePath] -> [[FilePath]]
  getTestFiles baseDir
    = map (filter ((== ".purs") . takeExtensions) . map (baseDir </>))
    . groupBy ((==) `on` extractPrefix)
    . sortBy (compare `on` extractPrefix)
    . map (makeRelative baseDir)

  -- Takes the test entry point from a group of purs files - this is determined
  -- by the file with the shortest path name, as everything but the main file
  -- will be under a subdirectory.
  getTestMain :: [FilePath] -> FilePath
  getTestMain = minimumBy (compare `on` length)

  -- Extracts the filename part of a .purs file, or if the file is in a
  -- subdirectory, the first part of that directory path.
  extractPrefix :: FilePath -> FilePath
  extractPrefix fp =
    let dir = takeDirectory fp
        ext = reverse ".purs"
    in if dir == "."
       then maybe fp reverse $ stripPrefix ext $ reverse fp
       else dir

  -- Scans a file for @shouldFailWith directives in the comments, used to
  -- determine expected failures
  getShouldFailWith :: FilePath -> IO [String]
  getShouldFailWith = extractPragma "shouldFailWith"

  -- Scans a file for @shouldWarnWith directives in the comments, used to
  -- determine expected warnings
  getShouldWarnWith :: FilePath -> IO [String]
  getShouldWarnWith = extractPragma "shouldWarnWith"

  extractPragma :: String -> FilePath -> IO [String]
  extractPragma pragma = fmap go . readUTF8File
    where
    go = lines >>> mapMaybe (stripPrefix ("-- @" ++ pragma ++ " ")) >>> map trim

inferForeignModules
  :: MonadIO m
  => [(FilePath, P.Module)]
  -> m (M.Map P.ModuleName FilePath)
inferForeignModules = P.inferForeignModules . fromList
  where
    fromList :: [(FilePath, P.Module)] -> M.Map P.ModuleName (Either P.RebuildPolicy FilePath)
    fromList = M.fromList . map ((P.getModuleName *** Right) . swap)

trim :: String -> String
trim = dropWhile isSpace >>> reverse >>> dropWhile isSpace >>> reverse

modulesDir :: FilePath
modulesDir = ".test_modules" </> "node_modules"

makeActions :: [P.Module] -> M.Map P.ModuleName FilePath -> P.MakeActions P.Make
makeActions modules foreigns = (P.buildMakeActions modulesDir (P.internalError "makeActions: input file map was read.") foreigns False)
                               { P.getInputTimestamp = getInputTimestamp
                               , P.getOutputTimestamp = getOutputTimestamp
                               , P.progress = const (pure ())
                               }
  where
  getInputTimestamp :: P.ModuleName -> P.Make (Either P.RebuildPolicy (Maybe UTCTime))
  getInputTimestamp mn
    | isSupportModule (P.runModuleName mn) = return (Left P.RebuildNever)
    | otherwise = return (Left P.RebuildAlways)
    where
    isSupportModule = flip elem (map (P.runModuleName . P.getModuleName) modules)

  getOutputTimestamp :: P.ModuleName -> P.Make (Maybe UTCTime)
  getOutputTimestamp mn = do
    let filePath = modulesDir </> T.unpack (P.runModuleName mn)
    exists <- liftIO $ doesDirectoryExist filePath
    return (if exists then Just (P.internalError "getOutputTimestamp: read timestamp") else Nothing)

runTest :: P.Make a -> IO (Either P.MultipleErrors a, P.MultipleErrors)
runTest = P.runMake P.defaultOptions

compile
  :: [P.Module]
  -> [P.ExternsFile]
  -> M.Map P.ModuleName FilePath
  -> [FilePath]
  -> ([P.Module] -> IO ())
  -> IO (Either P.MultipleErrors [P.ExternsFile], P.MultipleErrors)
compile supportModules supportExterns supportForeigns inputFiles check = runTest $ do
  fs <- liftIO $ readInput inputFiles
  ms <- P.parseModulesFromFiles id fs
  foreigns <- inferForeignModules ms
  liftIO (check (map snd ms))
  let actions = makeActions supportModules (foreigns `M.union` supportForeigns)
  case ms of
    [singleModule] -> pure <$> P.rebuildModule actions supportExterns (snd singleModule)
    _ -> P.make actions (supportModules ++ map snd ms)

assert
  :: [P.Module]
  -> [P.ExternsFile]
  -> M.Map P.ModuleName FilePath
  -> [FilePath]
  -> ([P.Module] -> IO ())
  -> (Either P.MultipleErrors P.MultipleErrors -> IO (Maybe String))
  -> Expectation
assert supportModules supportExterns supportForeigns inputFiles check f = do
  (e, w) <- compile supportModules supportExterns supportForeigns inputFiles check
  maybeErr <- f (const w <$> e)
  maybe (return ()) expectationFailure maybeErr

checkMain :: [P.Module] -> IO ()
checkMain ms =
  unless (any ((== P.moduleNameFromString "Main") . P.getModuleName) ms)
    (fail "Main module missing")

checkShouldFailWith :: [String] -> P.MultipleErrors -> Maybe String
checkShouldFailWith expected errs =
  let actual = map P.errorCode $ P.runMultipleErrors errs
  in if sort expected == sort (map T.unpack actual)
    then checkPositioned errs
    else Just $ "Expected these errors: " ++ show expected ++ ", but got these: "
      ++ show actual ++ ", full error messages: \n"
      ++ unlines (map (P.renderBox . P.prettyPrintSingleError P.defaultPPEOptions) (P.runMultipleErrors errs))

checkPositioned :: P.MultipleErrors -> Maybe String
checkPositioned errs =
  case mapMaybe guardSpans (P.runMultipleErrors errs) of
    [] ->
      Nothing
    errs' ->
      Just
        $ "Found errors with missing source spans:\n"
        ++ unlines (map (P.renderBox . P.prettyPrintSingleError P.defaultPPEOptions) errs')
  where
  guardSpans :: P.ErrorMessage -> Maybe P.ErrorMessage
  guardSpans err = case P.errorSpan err of
    Just ss | any (not . isNonsenseSpan) ss -> Nothing
    _ -> Just err

  isNonsenseSpan :: P.SourceSpan -> Bool
  isNonsenseSpan (P.SourceSpan spanName spanStart spanEnd) =
    spanName == "" || spanName == "<module>" || (spanStart == emptyPos && spanEnd == emptyPos)

  emptyPos :: P.SourcePos
  emptyPos = P.SourcePos 0 0

assertCompiles
  :: [P.Module]
  -> [P.ExternsFile]
  -> M.Map P.ModuleName FilePath
  -> [FilePath]
  -> Handle
  -> Expectation
assertCompiles supportModules supportExterns supportForeigns inputFiles outputFile =
  assert supportModules supportExterns supportForeigns inputFiles checkMain $ \e ->
    case e of
      Left errs -> return . Just . P.prettyPrintMultipleErrors P.defaultPPEOptions $ errs
      Right _ -> do
        process <- findNodeProcess
        let entryPoint = modulesDir </> "index.js"
        writeFile entryPoint "require('Main').main()"
        result <- traverse (\node -> readProcessWithExitCode node [entryPoint] "") process
        hPutStrLn outputFile $ "\n" <> takeFileName (last inputFiles) <> ":"
        case result of
          Just (ExitSuccess, out, err)
            | not (null err) -> return $ Just $ "Test wrote to stderr:\n\n" <> err
            | not (null out) && trim (last (lines out)) == "Done" -> do
                hPutStr outputFile out
                return Nothing
            | otherwise -> return $ Just $ "Test did not finish with 'Done':\n\n" <> out
          Just (ExitFailure _, _, err) -> return $ Just err
          Nothing -> return $ Just "Couldn't find node.js executable"

assertCompilesWithWarnings
  :: [P.Module]
  -> [P.ExternsFile]
  -> M.Map P.ModuleName FilePath
  -> [FilePath]
  -> [String]
  -> Expectation
assertCompilesWithWarnings supportModules supportExterns supportForeigns inputFiles shouldWarnWith =
  assert supportModules supportExterns supportForeigns inputFiles checkMain $ \e ->
    case e of
      Left errs ->
        return . Just . P.prettyPrintMultipleErrors P.defaultPPEOptions $ errs
      Right warnings ->
        return
          . fmap (printAllWarnings warnings)
          $ checkShouldFailWith shouldWarnWith warnings

  where
  printAllWarnings warnings =
    (<> "\n\n" <> P.prettyPrintMultipleErrors P.defaultPPEOptions warnings)

assertDoesNotCompile
  :: [P.Module]
  -> [P.ExternsFile]
  -> M.Map P.ModuleName FilePath
  -> [FilePath]
  -> [String]
  -> Expectation
assertDoesNotCompile supportModules supportExterns supportForeigns inputFiles shouldFailWith =
  assert supportModules supportExterns supportForeigns inputFiles noPreCheck $ \e ->
    case e of
      Left errs ->
        return $ if null shouldFailWith
          then Just $ "shouldFailWith declaration is missing (errors were: "
                      ++ show (map P.errorCode (P.runMultipleErrors errs))
                      ++ ")"
          else checkShouldFailWith shouldFailWith errs
      Right _ ->
        return $ Just "Should not have compiled"

  where
  noPreCheck = const (return ())

logpath :: FilePath
logpath = "purescript-output"

logfile :: FilePath
logfile = "psc-tests.out"