{-# LANGUAGE CPP, PatternGuards, RecordWildCards, ViewPatterns #-}

-- | Check the <TEST> annotations within source and hint files.
module Test.Annotations(testAnnotations, parseTestFile, TestCase(..)) where

import Control.Exception.Extra
import Control.Monad
import Control.Monad.IO.Class
import Data.Char
import Data.Either.Extra
import Data.Function
import Data.Functor
import Data.List.Extra
import Data.Maybe
import Data.Tuple.Extra
import System.Exit
import System.FilePath
import System.IO.Extra
import GHC.All
import qualified Data.ByteString.Char8 as BS

import Config.Type
import Idea
import Apply
import Extension
import Refact
import Test.Util
import Prelude
import Config.Yaml
import GHC.Data.FastString

import GHC.Util
import GHC.Types.SrcLoc
import Language.Haskell.GhclibParserEx.GHC.Utils.Outputable

#ifdef HS_YAML

import Data.YAML.Aeson (decode1Strict)
import Data.YAML (Pos)
import Data.ByteString (ByteString)

decodeEither' :: ByteString -> Either (Pos, String) ConfigYaml
decodeEither' = decode1Strict

#else

import Data.Yaml

#endif

-- Input, Output
-- Output = Nothing, should not match
-- Output = Just xs, should match xs
data TestCase = TestCase SrcLoc Refactor String (Maybe String) [Setting] deriving (Show)

data Refactor = TestRefactor | SkipRefactor deriving (Eq, Show)

testAnnotations :: [Setting] -> FilePath -> Maybe FilePath -> Test ()
testAnnotations setting file rpath = do
    tests <- liftIO $ parseTestFile file
    mapM_ f tests
    where
        f (TestCase loc refact inp out additionalSettings) = do
            ideas <- liftIO $ try_ $ do
                res <- applyHintFile defaultParseFlags (setting ++ additionalSettings) file $ Just inp
                evaluate $ length $ show res
                pure res

            let good = case (out, ideas) of
                    (Nothing, Right []) -> True
                    (Just x, Right [idea]) | match x idea -> True
                    _ -> False
            let bad =
                    [failed $
                        ["TEST FAILURE (" ++ show (either (const 1) length ideas) ++ " hints generated)"
                        ,"SRC: " ++ unsafePrettyPrint loc
                        ,"INPUT: " ++ inp] ++
                        map ("OUTPUT: " ++) (either (pure . show) (map show) ideas) ++
                        ["WANTED: " ++ fromMaybe "<failure>" out]
                        | not good] ++
                    [failed
                        ["TEST FAILURE (BAD LOCATION)"
                        ,"SRC: " ++ unsafePrettyPrint loc
                        ,"INPUT: " ++ inp
                        ,"OUTPUT: " ++ show i]
                        | i@Idea{..} <- fromRight [] ideas, let SrcLoc{..} = srcSpanStart ideaSpan, srcFilename == "" || srcLine == 0 || srcColumn == 0]
                        -- TODO: shouldn't these checks be == -1 instead?

            -- Skip refactoring test if the hlint test failed, or if the
            -- test is annotated with @NoRefactor.
            let skipRefactor = notNull bad || refact == SkipRefactor
            badRefactor <- if skipRefactor then pure [] else liftIO $ do
                refactorErr <- case ideas of
                    Right [] -> testRefactor rpath Nothing inp
                    Right [idea] -> testRefactor rpath (Just idea) inp
                    -- Skip refactoring test if there are multiple hints
                    _ -> pure []
                pure $ [failed $
                           ["TEST FAILURE (BAD REFACTORING)"
                           ,"SRC: " ++ unsafePrettyPrint loc
                           ,"INPUT: " ++ inp] ++ refactorErr
                           | notNull refactorErr]

            if null bad && null badRefactor then passed else sequence_ (bad ++ badRefactor)

        match "???" _ = True
        match (word1 -> ("@Message",msg)) i = ideaHint i == msg
        match (word1 -> ("@Note",note)) i = map show (ideaNote i) == [note]
        match "@NoNote" i = null (ideaNote i)
        match (word1 -> ('@':sev, msg)) i = sev == show (ideaSeverity i) && match msg i
        match msg i = on (==) norm (fromMaybe "" $ ideaTo i) msg

        -- FIXME: Should use a better check for expected results
        norm = filter $ \x -> not (isSpace x) && x /= ';'


parseTestFile :: FilePath -> IO [TestCase]
parseTestFile file =
    -- we remove all leading # symbols since Yaml only lets us do comments that way
    f Nothing TestRefactor . zipFrom 1 . map (dropPrefix "# ") . lines <$> readFile file
    where
        open :: String -> Maybe [Setting]
        open line
          |  "<TEST>" `isPrefixOf` line =
             let suffix = dropPrefix "<TEST>" line
                 config = decodeEither'  $ BS.pack suffix
             in case config of
                  Left err -> Just []
                  Right config -> Just $ settingsFromConfigYaml [config]
          | otherwise = Nothing

        shut :: String -> Bool
        shut = isPrefixOf "</TEST>"

        f :: Maybe [Setting] -> Refactor -> [(Int, String)] -> [TestCase]
        f Nothing _ ((i,x):xs) = f (open x) TestRefactor xs
        f (Just s) refact ((i,x):xs)
            | shut x = f Nothing TestRefactor xs
            | Just (x',_) <- stripInfix "@NoRefactor" x =
                f (Just s) SkipRefactor ((i, trimEnd x' ++ ['\\' | "\\" `isSuffixOf` x]) : xs)
            | null x || "-- " `isPrefixOf` x = f (Just s) refact xs
            | Just x <- stripSuffix "\\" x, (_,y):ys <- xs = f (Just s) refact $ (i,x++"\n"++y):ys
            | otherwise = parseTest refact file i x s : f (Just s) TestRefactor xs
        f _ _ [] = []


parseTest :: Refactor -> String -> Int -> String -> [Setting] -> TestCase
parseTest refact file i x = uncurry (TestCase (mkSrcLoc (mkFastString file) i 0) refact) $ f x
    where
        f x | Just x <- stripPrefix "<COMMENT>" x = first ("--"++) $ f x
        f (' ':'-':'-':xs) | null xs || " " `isPrefixOf` xs = ("", Just $ trimStart xs)
        f (x:xs) = first (x:) $ f xs
        f [] = ([], Nothing)


-- Returns an empty list if the refactoring test passes, otherwise
-- returns error messages.
testRefactor :: Maybe FilePath -> Maybe Idea -> String -> IO [String]
-- Skip refactoring test if the refactor binary is not found.
testRefactor Nothing _ _ = pure []
-- Skip refactoring test if there is no hint.
testRefactor _ Nothing _ = pure []
-- Skip refactoring test if the hint has no suggestion (such as "Parse error" or "Avoid restricted fuction").
testRefactor _ (Just idea) _ | isNothing (ideaTo idea) = pure []
-- Skip refactoring test if the hint does not support refactoring.
testRefactor _ (Just idea) _ | null (ideaRefactoring idea) = pure []
testRefactor (Just rpath) (Just idea) inp = withTempFile $ \tempInp -> withTempFile $ \tempHints -> do
    let refact = (show idea, ideaRefactoring idea)
        -- Ignores spaces and semicolons since unsafePrettyPrint may differ from apply-refact.
        process = filter (\c -> not (isSpace c) && c /= ';')
        matched expected g actual = process expected `g` process actual
        x `isProperSubsequenceOf` y = x /= y && x `isSubsequenceOf` y
    writeFile tempInp inp
    writeFile tempHints (show [refact])
    exitCode <- runRefactoring rpath tempInp tempHints defaultExtensions [] "--inplace"
    refactored <- readFile tempInp
    pure $ case exitCode of
        ExitFailure ec -> ["Refactoring failed: exit code " ++ show ec]
        ExitSuccess -> case ideaTo idea of
            -- The hint's suggested replacement is @Just ""@, which means the hint
            -- suggests removing something from the input. The refactoring output
            -- should be a proper subsequence of the input.
            Just "" | not (matched refactored isProperSubsequenceOf inp) ->
                ["Refactor output is expected to be a proper subsequence of: " ++ inp, "Actual: " ++ refactored]
            -- The hint has a suggested replacement. The suggested replacement
            -- should be a substring of the refactoring output.
            Just to | not (matched to isInfixOf refactored) ->
                ["Refactor output is expected to contain: " ++ to, "Actual: " ++ refactored]
            _ -> []