{-#LANGUAGE ScopedTypeVariables#-}

module StackTest where

import Control.Monad
import Control.Monad.IO.Class
import Control.Monad.Trans.Reader
import Control.Concurrent
import Control.Exception
import System.Environment
import System.Directory
import System.IO
import System.IO.Error
import System.Process
import System.Exit
import System.Info (arch, os)
import GHC.Stack (HasCallStack)

run' :: HasCallStack => FilePath -> [String] -> IO ExitCode
run' cmd args = do
    logInfo $ "Running: " ++ cmd ++ " " ++ unwords (map showProcessArgDebug args)
    (Nothing, Nothing, Nothing, ph) <- createProcess (proc cmd args)
    waitForProcess ph

run :: HasCallStack => FilePath -> [String] -> IO ()
run cmd args = do
    ec <- run' cmd args
    unless (ec == ExitSuccess) $ error $ "Exited with exit code: " ++ show ec

runShell :: HasCallStack => String -> IO ()
runShell cmd = do
    logInfo $ "Running: " ++ cmd
    (Nothing, Nothing, Nothing, ph) <- createProcess (shell cmd)
    ec <- waitForProcess ph
    unless (ec == ExitSuccess) $ error $ "Exited with exit code: " ++ show ec

runWithCwd :: HasCallStack => FilePath -> String -> [String] -> IO String
runWithCwd cwdPath cmd args = do
    logInfo $ "Running: " ++ cmd
    let cp = proc cmd args
    (ec, stdoutStr, _) <- readCreateProcessWithExitCode (cp { cwd = Just cwdPath }) ""
    unless (ec == ExitSuccess) $ error $ "Exited with exit code: " ++ show ec
    return stdoutStr

stackExe :: IO String
stackExe = getEnv "STACK_EXE"

stackSrc :: IO String
stackSrc = getEnv "SRC_DIR"

testDir :: IO String
testDir = getEnv "TEST_DIR"

stack' :: HasCallStack => [String] -> IO ExitCode
stack' args = do
    stackEnv <- stackExe
    run' stackEnv args

stack :: HasCallStack => [String] -> IO ()
stack args = do
    ec <- stack' args
    unless (ec == ExitSuccess) $ error $ "Exited with exit code: " ++ show ec

-- Temporary workaround for Windows to ignore exceptions arising out
-- of Windows when we do stack clean. More info here: https://github.com/commercialhaskell/stack/issues/4936
stackCleanFull :: HasCallStack => IO ()
stackCleanFull = stackIgnoreException ["clean", "--full"]

-- Temporary workaround for Windows to ignore exceptions arising out
-- of Windows when we do stack clean. More info here: https://github.com/commercialhaskell/stack/issues/4936
stackIgnoreException :: HasCallStack => [String] -> IO ()
stackIgnoreException args = if isWindows
                            then void (stack' args) `catch` (\(_e :: IOException) -> return ())
                            else stack args

stackErr :: HasCallStack => [String] -> IO ()
stackErr args = do
    ec <- stack' args
    when (ec == ExitSuccess) $ error "stack was supposed to fail, but didn't"

type Repl = ReaderT ReplConnection IO

data ReplConnection
  = ReplConnection
    { replStdin  :: Handle
    , replStdout :: Handle
    }

nextPrompt :: Repl ()
nextPrompt = do
    (ReplConnection _ inputHandle) <- ask
    c <- liftIO $ hGetChar inputHandle
    if c == '>'
      then do _ <- liftIO $ hGetChar inputHandle
              return ()
      else nextPrompt

replCommand :: String -> Repl ()
replCommand cmd = do
    (ReplConnection input _) <- ask
    liftIO $ hPutStrLn input cmd

replGetLine :: Repl String
replGetLine = ask >>= liftIO . hGetLine . replStdout

replGetChar :: Repl Char
replGetChar = ask >>= liftIO . hGetChar . replStdout

runRepl :: HasCallStack => FilePath -> [String] -> ReaderT ReplConnection IO () -> IO ExitCode
runRepl cmd args actions = do
    logInfo $ "Running: " ++ cmd ++ " " ++ unwords (map showProcessArgDebug args)
    (Just rStdin, Just rStdout, Just rStderr, ph) <-
        createProcess (proc cmd args)
        { std_in = CreatePipe
        , std_out = CreatePipe
        , std_err = CreatePipe
        }
    hSetBuffering rStdin NoBuffering
    hSetBuffering rStdout NoBuffering
    hSetBuffering rStderr NoBuffering

    _ <- forkIO $ withFile "/tmp/stderr" WriteMode
        $ \err -> do
            hSetBuffering err NoBuffering
            forever $ catch (hGetChar rStderr >>= hPutChar err)
                    $ \e -> unless (isEOFError e) $ throw e

    runReaderT (nextPrompt >> actions) (ReplConnection rStdin rStdout)
    waitForProcess ph

repl :: HasCallStack => [String] -> Repl () -> IO ()
repl args action = do
    stackExe' <- stackExe
    ec <- runRepl stackExe' ("repl":args) action
    unless (ec == ExitSuccess) $ return ()
        -- TODO: Understand why the exit code is 1 despite running GHCi tests
        -- successfully.
        -- else error $ "Exited with exit code: " ++ show ec

stackStderr :: HasCallStack => [String] -> IO (ExitCode, String)
stackStderr args = do
    stackExe' <- stackExe
    logInfo $ "Running: " ++ stackExe' ++ " " ++ unwords (map showProcessArgDebug args)
    (ec, _, err) <- readProcessWithExitCode stackExe' args ""
    hPutStr stderr err
    return (ec, err)

-- | Run stack with arguments and apply a check to the resulting
-- stderr output if the process succeeded.
stackCheckStderr :: HasCallStack => [String] -> (String -> IO ()) -> IO ()
stackCheckStderr args check = do
    (ec, err) <- stackStderr args
    if ec /= ExitSuccess
        then error $ "Exited with exit code: " ++ show ec
        else check err

-- | Same as 'stackCheckStderr', but ensures that the Stack process
-- fails.
stackErrStderr :: HasCallStack => [String] -> (String -> IO ()) -> IO ()
stackErrStderr args check = do
    (ec, err) <- stackStderr args
    if ec == ExitSuccess
        then error "Stack process succeeded, but it shouldn't"
        else check err

runEx :: HasCallStack => FilePath -> String -> IO (ExitCode, String, String)
runEx cmd args = runEx' cmd $ words args

runEx' :: HasCallStack => FilePath -> [String] -> IO (ExitCode, String, String)
runEx' cmd args = do
    logInfo $ "Running: " ++ cmd ++ " " ++ unwords (map showProcessArgDebug args)
    (ec, out, err) <- readProcessWithExitCode cmd args ""
    putStr out
    hPutStr stderr err
    return (ec, out, err)

-- | Run stack with arguments and apply a check to the resulting
-- stdout output if the process succeeded.
--
-- Take care with newlines; if the output includes a newline character that
-- should not be there, use 'Data.List.Extra.trimEnd' to remove it.
stackCheckStdout :: HasCallStack => [String] -> (String -> IO ()) -> IO ()
stackCheckStdout args check = do
    stackExe' <- stackExe
    (ec, out, _) <- runEx' stackExe' args
    if ec /= ExitSuccess
        then error $ "Exited with exit code: " ++ show ec
        else check out

doesNotExist :: HasCallStack => FilePath -> IO ()
doesNotExist fp = do
    logInfo $ "doesNotExist " ++ fp
    exists <- doesFileOrDirExist fp
    case exists of
      (Right msg) -> error msg
      (Left _) -> return ()

doesExist :: HasCallStack => FilePath -> IO ()
doesExist fp = do
    logInfo $ "doesExist " ++ fp
    exists <- doesFileOrDirExist fp
    case exists of
      (Right _) -> return ()
      (Left _) -> error "No file or directory exists"

doesFileOrDirExist :: HasCallStack => FilePath -> IO (Either () String)
doesFileOrDirExist fp = do
    isFile <- doesFileExist fp
    if isFile
        then return (Right ("File exists: " ++ fp))
        else do
            isDir <- doesDirectoryExist fp
            if isDir
                then return (Right ("Directory exists: " ++ fp))
                else return (Left ())

copy :: HasCallStack => FilePath -> FilePath -> IO ()
copy src dest = do
    logInfo ("Copy " ++ show src ++ " to " ++ show dest)
    System.Directory.copyFile src dest

fileContentsMatch :: HasCallStack => FilePath -> FilePath -> IO ()
fileContentsMatch f1 f2 = do
    doesExist f1
    doesExist f2
    f1Contents <- readFile f1
    f2Contents <- readFile f2
    unless (f1Contents == f2Contents) $
        error ("contents do not match for " ++ show f1 ++ " " ++ show f2)

logInfo :: String -> IO ()
logInfo = hPutStrLn stderr

-- TODO: use stack's process running utilties?  (better logging)
-- for now just copy+modifying this one from System.Process.Log

-- | Show a process arg including speechmarks when necessary. Just for
-- debugging purposes, not functionally important.
showProcessArgDebug :: String -> String
showProcessArgDebug x
    | any special x = show x
    | otherwise = x
  where special '"' = True
        special ' ' = True
        special _ = False

-- | Extension of executables
exeExt :: String
exeExt = if isWindows then ".exe" else ""

-- | Is the OS Windows?
isWindows :: Bool
isWindows = os == "mingw32"

isLinux :: Bool
isLinux = os == "linux"

-- | Is the OS Alpine Linux?
getIsAlpine :: IO Bool
getIsAlpine = doesFileExist "/etc/alpine-release"

-- | Is the architecture ARM?
isARM :: Bool
isARM = arch == "arm"

-- | Is the OS Mac OS X?
isMacOSX :: Bool
isMacOSX = os == "darwin"

-- | To avoid problems with GHC version mismatch when a new LTS major
-- version is released, pass this argument to @stack@ when running in
-- a global context. The LTS major version here should match that of
-- the main @stack.yaml@.
--
defaultResolverArg :: String
defaultResolverArg = "--resolver=lts-14.27"

-- | Remove a file and ignore any warnings about missing files.
removeFileIgnore :: HasCallStack => FilePath -> IO ()
removeFileIgnore fp = removeFile fp `catch` \e ->
  if isDoesNotExistError e
    then return ()
    else throwIO e

-- | Remove a directory and ignore any warnings about missing files.
removeDirIgnore :: HasCallStack => FilePath -> IO ()
removeDirIgnore fp = removeDirectoryRecursive fp `catch` \e ->
  if isDoesNotExistError e
    then return ()
    else throwIO e

-- | Changes working directory to Stack source directory
withSourceDirectory :: HasCallStack => IO () -> IO ()
withSourceDirectory action = do
  dir <- stackSrc
  currentDirectory <- getCurrentDirectory
  let enterDir = setCurrentDirectory dir
      exitDir = setCurrentDirectory currentDirectory
  bracket_ enterDir exitDir action

-- | Mark a test as superslow, only to be run when explicitly requested.
superslow :: HasCallStack => IO () -> IO ()
superslow inner = do
  mres <- lookupEnv "STACK_TEST_SPEED"
  case mres of
    Just "NORMAL" -> logInfo "Skipping superslow test"
    Just "SUPERSLOW" -> do
      logInfo "Running superslow test, hold on to your butts"
      inner
    Nothing -> do
      logInfo "No STACK_TEST_SPEED specified. Executing superslow test, hold on to your butts"
      inner
    Just x -> error $ "Invalid value for STACK_TEST_SPEED env var: " ++ show x