module Hedgehog.Extras.Test.Golden
  ( diffVsGoldenFile,
    diffFileVsGoldenFile,
  ) where

import           Control.Applicative
import           Control.Exception (bracket_)
import           Control.Monad
import           Control.Monad.IO.Class (MonadIO (liftIO))
import           Data.Algorithm.Diff (PolyDiff (Both), getGroupedDiff)
import           Data.Algorithm.DiffOutput (ppDiff)
import           Data.Bool
import           Data.Eq
import           Data.Function
import           Data.Maybe
import           Data.Monoid
import           Data.String
import           GHC.Stack (HasCallStack, callStack)
import           Hedgehog (MonadTest)
import           Hedgehog.Extras.Test.Base (failMessage)
import           System.FilePath (takeDirectory)
import           System.IO (FilePath, IO)

import qualified Control.Concurrent.QSem as IO
import qualified Data.List as List
import qualified GHC.Stack as GHC
import qualified Hedgehog.Extras.Test as H
import qualified Hedgehog.Internal.Property as H
import qualified System.Directory as IO
import qualified System.Environment as IO
import qualified System.IO as IO
import qualified System.IO.Unsafe as IO

sem :: IO.QSem
sem :: QSem
sem = forall a. IO a -> a
IO.unsafePerformIO forall a b. (a -> b) -> a -> b
$ Int -> IO QSem
IO.newQSem Int
1
{-# NOINLINE sem #-}

semBracket :: IO a -> IO a
semBracket :: forall a. IO a -> IO a
semBracket = forall a b c. IO a -> IO b -> IO c -> IO c
bracket_ (QSem -> IO ()
IO.waitQSem QSem
sem) (QSem -> IO ()
IO.signalQSem QSem
sem)

-- | The file to log whenever a golden file is referenced.
mGoldenFileLogFile :: Maybe FilePath
mGoldenFileLogFile :: Maybe String
mGoldenFileLogFile = forall a. IO a -> a
IO.unsafePerformIO forall a b. (a -> b) -> a -> b
$
  String -> IO (Maybe String)
IO.lookupEnv String
"GOLDEN_FILE_LOG_FILE"

-- | Whether the test should create the golden files if the file does ont exist.
createFiles :: Bool
createFiles :: Bool
createFiles = forall a. IO a -> a
IO.unsafePerformIO forall a b. (a -> b) -> a -> b
$ do
  Maybe String
value <- String -> IO (Maybe String)
IO.lookupEnv String
"CREATE_GOLDEN_FILES"
  forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ Maybe String
value forall a. Eq a => a -> a -> Bool
== forall a. a -> Maybe a
Just String
"1"

-- | Diff contents against the golden file.  If CREATE_GOLDEN_FILES environment is
-- set to "1", then should the gold file not exist it would be created.  If
-- GOLDEN_FILE_LOG_FILE is set to a filename, then the golden file path will be
-- logged to the specified file.
--
-- Set the environment variable when you intend to generate or re-generate the golden
-- file for example when running the test for the first time or if the golden file
-- genuinely needs to change.
--
-- To re-generate a golden file you must also delete the golden file because golden
-- files are never overwritten.
--
-- TODO: Improve the help output by saying the difference of
-- each input.
diffVsGoldenFile
  :: HasCallStack
  => (MonadIO m, MonadTest m)
  => String   -- ^ Actual content
  -> FilePath -- ^ Reference file
  -> m ()
diffVsGoldenFile :: forall (m :: * -> *).
(HasCallStack, MonadIO m, MonadTest m) =>
String -> String -> m ()
diffVsGoldenFile String
actualContent String
referenceFile = forall a. HasCallStack => (HasCallStack => a) -> a
GHC.withFrozenCallStack forall a b. (a -> b) -> a -> b
$ do
  forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
t a -> (a -> m b) -> m ()
forM_ Maybe String
mGoldenFileLogFile forall a b. (a -> b) -> a -> b
$ \String
logFile ->
    forall (m :: * -> *) a. MonadIO m => IO a -> m a
liftIO forall a b. (a -> b) -> a -> b
$ forall a. IO a -> IO a
semBracket forall a b. (a -> b) -> a -> b
$ String -> String -> IO ()
IO.appendFile String
logFile forall a b. (a -> b) -> a -> b
$ String
referenceFile forall a. Semigroup a => a -> a -> a
<> String
"\n"

  Bool
fileExists <- forall (m :: * -> *) a. MonadIO m => IO a -> m a
liftIO forall a b. (a -> b) -> a -> b
$ String -> IO Bool
IO.doesFileExist String
referenceFile

  if Bool
fileExists
    then do
      [String]
referenceLines <- String -> [String]
List.lines forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> forall (m :: * -> *).
(MonadTest m, MonadIO m, HasCallStack) =>
String -> m String
H.readFile String
referenceFile
      let difference :: [Diff [String]]
difference = forall a. Eq a => [a] -> [a] -> [Diff [a]]
getGroupedDiff [String]
actualLines [String]
referenceLines
      case [Diff [String]]
difference of
        []       -> forall (f :: * -> *) a. Applicative f => a -> f a
pure ()
        [Both{}] -> forall (f :: * -> *) a. Applicative f => a -> f a
pure ()
        [Diff [String]]
_        -> do
          forall (m :: * -> *). (MonadTest m, HasCallStack) => String -> m ()
H.note_ forall a b. (a -> b) -> a -> b
$ String
"Golden test failed against golden file: " forall a. Semigroup a => a -> a -> a
<> String
referenceFile
          forall (m :: * -> *) a. MonadTest m => CallStack -> String -> m a
failMessage HasCallStack => CallStack
callStack forall a b. (a -> b) -> a -> b
$ [Diff [String]] -> String
ppDiff [Diff [String]]
difference
    else if Bool
createFiles
      then do
        -- CREATE_GOLDEN_FILES is set, so we create any golden files that don't
        -- already exist.
        forall (m :: * -> *). (MonadTest m, HasCallStack) => String -> m ()
H.note_ forall a b. (a -> b) -> a -> b
$ String
"Creating golden file " forall a. Semigroup a => a -> a -> a
<> String
referenceFile
        forall (m :: * -> *).
(MonadTest m, MonadIO m, HasCallStack) =>
String -> m ()
H.createDirectoryIfMissing_ (String -> String
takeDirectory String
referenceFile)
        forall (m :: * -> *).
(MonadTest m, MonadIO m, HasCallStack) =>
String -> String -> m ()
H.writeFile String
referenceFile String
actualContent
      else do
        forall (m :: * -> *). (MonadTest m, HasCallStack) => String -> m ()
H.note_ forall a b. (a -> b) -> a -> b
$ forall a. Monoid a => [a] -> a
mconcat
          [ String
"Golden file " forall a. Semigroup a => a -> a -> a
<> String
referenceFile
          , String
" does not exist.  To create, run with CREATE_GOLDEN_FILES=1"
          ]
        forall (m :: * -> *) a. (MonadTest m, HasCallStack) => m a
H.failure
  where
    actualLines :: [String]
actualLines = String -> [String]
List.lines String
actualContent

-- | Diff file against the golden file.  If CREATE_GOLDEN_FILES environment is
-- set to "1", then should the gold file not exist it would be created.  If
-- GOLDEN_FILE_LOG_FILE is set to a filename, then the golden file path will be
-- logged to the specified file.
--
-- Set the environment variable when you intend to generate or re-generate the golden
-- file for example when running the test for the first time or if the golden file
-- genuinely needs to change.
--
-- To re-generate a golden file you must also delete the golden file because golden
-- files are never overwritten.
diffFileVsGoldenFile
  :: HasCallStack
  => (MonadIO m, MonadTest m)
  => FilePath -- ^ Actual file
  -> FilePath -- ^ Reference file
  -> m ()
diffFileVsGoldenFile :: forall (m :: * -> *).
(HasCallStack, MonadIO m, MonadTest m) =>
String -> String -> m ()
diffFileVsGoldenFile String
actualFile String
referenceFile = forall a. HasCallStack => (HasCallStack => a) -> a
GHC.withFrozenCallStack forall a b. (a -> b) -> a -> b
$ do
  String
contents <- forall (m :: * -> *).
(MonadTest m, MonadIO m, HasCallStack) =>
String -> m String
H.readFile String
actualFile
  forall (m :: * -> *).
(HasCallStack, MonadIO m, MonadTest m) =>
String -> String -> m ()
diffVsGoldenFile String
contents String
referenceFile