{-# LANGUAGE QuasiQuotes #-}

module Commands.Repl where

import Commands.Base hiding (command)
import Commands.Extra.Paths
import Commands.Repl.Options
import Control.Exception (throwIO)
import Control.Monad.State.Strict qualified as State
import Data.String.Interpolate (i, __i)
import Evaluator
import Juvix.Compiler.Builtins.Effect
import Juvix.Compiler.Core.Error qualified as Core
import Juvix.Compiler.Core.Extra qualified as Core
import Juvix.Compiler.Core.Info qualified as Info
import Juvix.Compiler.Core.Info.NoDisplayInfo qualified as Info
import Juvix.Compiler.Core.Language qualified as Core
import Juvix.Compiler.Core.Pretty qualified as Core
import Juvix.Compiler.Core.Translation.FromInternal.Data qualified as Core
import Juvix.Compiler.Internal.Language qualified as Internal
import Juvix.Compiler.Internal.Pretty qualified as Internal
import Juvix.Data.Error.GenericError qualified as Error
import Juvix.Extra.Paths
import Juvix.Extra.Version
import Juvix.Prelude.Pretty qualified as P
import System.Console.ANSI qualified as Ansi
import System.Console.Haskeline
import System.Console.Repline
import System.Console.Repline qualified as Repline

type ReplS = State.StateT ReplState IO

type Repl a = HaskelineT ReplS a

data ReplContext = ReplContext
  { _replContextBuiltins :: BuiltinsState,
    _replContextExpContext :: ExpressionContext,
    _replContextEntryPoint :: EntryPoint
  }

data ReplState = ReplState
  { _replStatePkgDir :: Path Abs Dir,
    _replStateInvokeDir :: Path Abs Dir,
    _replStateContext :: Maybe ReplContext,
    _replStateGlobalOptions :: GlobalOptions
  }

makeLenses ''ReplState
makeLenses ''ReplContext

helpTxt :: (MonadIO m) => m ()
helpTxt =
  liftIO
    ( putStrLn
        [__i|
  EXPRESSION                Evaluate an expression in the context of the currently loaded module
  :help                     Print help text and describe options
  :load       FILE          Load a file into the REPL
  :reload                   Reload the currently loaded file
  :prelude                  Load the Prelude from the standard library
  :type       EXPRESSION    Infer the type of an expression
  :core       EXPRESSION    Translate the expression to JuvixCore
  :multiline                Start a multi-line input. Submit with <Ctrl-D>
  :root                     Print the current project root
  :version                  Display the Juvix version
  :quit                     Exit the REPL
  |]
    )

noFileLoadedMsg :: (MonadIO m) => m ()
noFileLoadedMsg = liftIO (putStrLn "No file loaded. Load a file using the `:load FILE` command.")

welcomeMsg :: (MonadIO m) => m ()
welcomeMsg = liftIO (putStrLn [i|Juvix REPL version #{versionTag}: https://juvix.org. Run :help for help|])

runCommand :: (Members '[Embed IO, App] r) => ReplOptions -> Sem r ()
runCommand opts = do
  root <- askPkgDir
  buildDir <- askBuildDir
  package <- askPackage
  let getReplEntryPoint :: SomeBase File -> Repl EntryPoint
      getReplEntryPoint inputFile = do
        gopts <- State.gets (^. replStateGlobalOptions)
        absInputFile :: Path Abs File <- replMakeAbsolute inputFile
        return $
          EntryPoint
            { _entryPointRoot = root,
              _entryPointBuildDir = buildDir,
              _entryPointResolverRoot = root,
              _entryPointNoTermination = gopts ^. globalNoTermination,
              _entryPointNoPositivity = gopts ^. globalNoPositivity,
              _entryPointNoStdlib = gopts ^. globalNoStdlib,
              _entryPointPackage = package,
              _entryPointModulePaths = pure absInputFile,
              _entryPointGenericOptions = project gopts,
              _entryPointStdin = Nothing
            }

      printHelpTxt :: String -> Repl ()
      printHelpTxt _ = helpTxt

      multilineCmd :: String
      multilineCmd = "multiline"

      quit :: String -> Repl ()
      quit _ = liftIO (throwIO Interrupt)

      loadEntryPoint :: EntryPoint -> Repl ()
      loadEntryPoint ep = do
        (artif, res) <- liftIO (runIO' iniState ep upToCore)
        State.modify
          ( set
              replStateContext
              ( Just
                  ( ReplContext
                      { _replContextBuiltins = artif ^. artifactBuiltins,
                        _replContextExpContext = expressionContext res,
                        _replContextEntryPoint = ep
                      }
                  )
              )
          )
        let epPath :: Path Abs File = ep ^. entryPointModulePaths . _head1
        liftIO (putStrLn [i|OK loaded: #{toFilePath epPath}|])

      reloadFile :: String -> Repl ()
      reloadFile _ = do
        mentryPoint <- State.gets (fmap (^. replContextEntryPoint) . (^. replStateContext))
        case mentryPoint of
          Just entryPoint -> do
            loadEntryPoint entryPoint
          Nothing -> noFileLoadedMsg

      pSomeFile :: String -> SomeBase File
      pSomeFile = someFile . unpack . strip . pack

      loadFile :: SomeBase File -> Repl ()
      loadFile f = do
        entryPoint <- getReplEntryPoint f
        loadEntryPoint entryPoint

      loadPrelude :: Repl ()
      loadPrelude = loadDefaultPrelude

      loadDefaultPrelude :: Repl ()
      loadDefaultPrelude = defaultPreludeEntryPoint >>= loadEntryPoint

      printRoot :: String -> Repl ()
      printRoot _ = do
        r <- State.gets (^. replStatePkgDir)
        liftIO $ putStrLn (pack (toFilePath r))

      displayVersion :: String -> Repl ()
      displayVersion _ = liftIO (putStrLn versionTag)

      command :: String -> Repl ()
      command input = Repline.dontCrash $ do
        ctx <- State.gets (^. replStateContext)
        case ctx of
          Just ctx' -> do
            evalRes <- compileThenEval ctx' input
            case evalRes of
              Left err -> printError err
              Right n
                | Info.member Info.kNoDisplayInfo (Core.getInfo n) -> return ()
              Right n -> renderOut (Core.ppOut opts n)
          Nothing -> noFileLoadedMsg
        where
          defaultLoc :: Interval
          defaultLoc = singletonInterval (mkInitialLoc replPath)

          compileThenEval :: ReplContext -> String -> Repl (Either JuvixError Core.Node)
          compileThenEval ctx s = bindEither compileString eval
            where
              eval :: Core.Node -> Repl (Either JuvixError Core.Node)
              eval n =
                liftIO $
                  mapLeft
                    (JuvixError @Core.CoreError)
                    <$> doEvalIO False defaultLoc (ctx ^. replContextExpContext . contextCoreResult . Core.coreResultTable) n

              compileString :: Repl (Either JuvixError Core.Node)
              compileString = liftIO $ compileExpressionIO' ctx (strip (pack s))

              bindEither :: (Monad m) => m (Either e a) -> (a -> m (Either e b)) -> m (Either e b)
              bindEither x f = join <$> (x >>= mapM f)

      core :: String -> Repl ()
      core input = Repline.dontCrash $ do
        ctx <- State.gets (^. replStateContext)
        case ctx of
          Just ctx' -> do
            compileRes <- liftIO (compileExpressionIO' ctx' (strip (pack input)))
            case compileRes of
              Left err -> printError err
              Right n -> renderOut (Core.ppOut opts n)
          Nothing -> noFileLoadedMsg

      inferType :: String -> Repl ()
      inferType input = Repline.dontCrash $ do
        ctx <- State.gets (^. replStateContext)
        gopts <- State.gets (^. replStateGlobalOptions)
        case ctx of
          Just ctx' -> do
            compileRes <- liftIO (inferExpressionIO' ctx' (strip (pack input)))
            case compileRes of
              Left err -> printError err
              Right n -> renderOut (Internal.ppOut (project' @GenericOptions gopts) n)
          Nothing -> noFileLoadedMsg

      options :: [(String, String -> Repl ())]
      options =
        [ ("help", Repline.dontCrash . printHelpTxt),
          -- `multiline` is included here for auto-completion purposes only.
          -- `repline`'s `multilineCommand` logic overrides this no-op.
          (multilineCmd, Repline.dontCrash . \_ -> return ()),
          ("quit", quit),
          ("load", Repline.dontCrash . loadFile . pSomeFile),
          ("reload", Repline.dontCrash . reloadFile),
          ("prelude", Repline.dontCrash . const loadPrelude),
          ("root", printRoot),
          ("type", inferType),
          ("version", displayVersion),
          ("core", core)
        ]

      defaultMatcher :: [(String, CompletionFunc ReplS)]
      defaultMatcher = [(":load", fileCompleter)]

      optsCompleter :: WordCompleter ReplS
      optsCompleter n = do
        let names = (":" <>) . fst <$> options
        return (filter (isPrefixOf n) names)

      banner :: MultiLine -> Repl String
      banner = \case
        MultiLine -> return "... "
        SingleLine -> do
          mctx <- State.gets (fmap (^. replContextExpContext) . (^. replStateContext))
          case mctx of
            Just ctx -> return [i|#{unpack (P.prettyText (mainModuleTopPath ctx))}> |]
            Nothing -> return "juvix> "

      prefix :: Maybe Char
      prefix = Just ':'

      multilineCommand :: Maybe String
      multilineCommand = Just multilineCmd

      initialiser :: Repl ()
      initialiser = do
        gopts <- State.gets (^. replStateGlobalOptions)
        welcomeMsg
        unless
          (opts ^. replNoPrelude || gopts ^. globalNoStdlib)
          (maybe loadPrelude (loadFile . (^. pathPath)) (opts ^. replInputFile))

      finaliser :: Repl ExitDecision
      finaliser = return Exit

      tabComplete :: CompleterStyle ReplS
      tabComplete = Prefix (wordCompleter optsCompleter) defaultMatcher

      replAction :: ReplS ()
      replAction = do
        evalReplOpts
          ReplOpts
            { prefix,
              multilineCommand,
              initialiser,
              finaliser,
              tabComplete,
              command,
              options,
              banner
            }

  pkgDir <- askPkgDir
  invokeDir <- askInvokeDir
  globalOptions <- askGlobalOptions
  embed
    ( State.evalStateT
        replAction
        ( ReplState
            { _replStatePkgDir = pkgDir,
              _replStateInvokeDir = invokeDir,
              _replStateContext = Nothing,
              _replStateGlobalOptions = globalOptions
            }
        )
    )

defaultPreludeEntryPoint :: Repl EntryPoint
defaultPreludeEntryPoint = do
  opts <- State.gets (^. replStateGlobalOptions)
  root <- State.gets (^. replStatePkgDir)
  let buildDir = rootBuildDir root
      defStdlibDir = defaultStdlibPath buildDir
  return $
    EntryPoint
      { _entryPointRoot = root,
        _entryPointResolverRoot = defStdlibDir,
        _entryPointBuildDir = buildDir,
        _entryPointNoTermination = opts ^. globalNoTermination,
        _entryPointNoPositivity = opts ^. globalNoPositivity,
        _entryPointNoStdlib = opts ^. globalNoStdlib,
        _entryPointPackage = defaultPackage root buildDir,
        _entryPointModulePaths = pure (defStdlibDir <//> preludePath),
        _entryPointGenericOptions = project opts,
        _entryPointStdin = Nothing
      }

replMakeAbsolute :: SomeBase b -> Repl (Path Abs b)
replMakeAbsolute = \case
  Abs p -> return p
  Rel r -> do
    invokeDir <- State.gets (^. replStateInvokeDir)
    return (invokeDir <//> r)

inferExpressionIO' :: ReplContext -> Text -> IO (Either JuvixError Internal.Expression)
inferExpressionIO' ctx = inferExpressionIO replPath (ctx ^. replContextExpContext) (ctx ^. replContextBuiltins)

compileExpressionIO' :: ReplContext -> Text -> IO (Either JuvixError Core.Node)
compileExpressionIO' ctx = compileExpressionIO replPath (ctx ^. replContextExpContext) (ctx ^. replContextBuiltins)

render' :: (P.HasAnsiBackend a, P.HasTextBackend a) => a -> Repl ()
render' t = do
  opts <- State.gets (^. replStateGlobalOptions)
  hasAnsi <- liftIO (Ansi.hSupportsANSIColor stdout)
  liftIO (P.renderIO (not (opts ^. globalNoColors) && hasAnsi) t)

renderOut :: (P.HasAnsiBackend a, P.HasTextBackend a) => a -> Repl ()
renderOut t = render' t >> liftIO (putStrLn "")

printError :: JuvixError -> Repl ()
printError e = do
  opts <- State.gets (^. replStateGlobalOptions)
  hasAnsi <- liftIO (Ansi.hSupportsANSIColor stderr)
  liftIO $ hPutStrLn stderr $ run (runReader (project' @GenericOptions opts) (Error.render (not (opts ^. globalNoColors) && hasAnsi) False e))