{-# LANGUAGE LambdaCase, ViewPatterns, RecordWildCards #-}
module Development.Debug.Interactive where

import System.IO
import System.Exit
import System.Directory
import System.Console.Haskeline
import System.Console.Haskeline.Completion
import Control.Monad.State
import Control.Monad.Reader
import Control.Monad.RWS
import Options.Applicative
import Options.Applicative.BashCompletion

import Development.Debug.Adapter.Flags  -- use different namespace for common things
import Development.Debug.Adapter.Handles

import GHC.Debugger.Logger
import GHC.Debugger.Interface.Messages
import GHC.Debugger.Monad
import GHC.Debugger

-- | Interactive debugging monad
type InteractiveDM a = InputT (RWST (FilePath{-entry file-},String{-entry point-}, [String]{-run args-}) ()
                                (Maybe Command{-last cmd-}) Debugger) a

data InteractiveLog
  = DebuggerLog DebuggerLog
  | FlagsLog FlagsLog

instance Pretty InteractiveLog where
  pretty = \ case
    DebuggerLog msg -> pretty msg
    FlagsLog msg -> pretty msg

-- | Run it
runIDM :: String   -- ^ entryPoint
       -> FilePath -- ^ entryFile
       -> [String] -- ^ entryArgs
       -> [String] -- ^ extraGhcArgs
       -> InteractiveDM a
       -> IO a
runIDM entryPoint entryFile entryArgs extraGhcArgs act = do
  projectRoot <- getCurrentDirectory
  l           <- handleLogger stdout
  let
    loggerWithSev = cmap renderPrettyWithSeverity (fromCologAction l)
  let hieBiosLogger = cmapWithSev FlagsLog loggerWithSev
  cradle <- hieBiosCradle hieBiosLogger projectRoot entryFile >>=
    \case
      Left e -> exitWithMsg e
      Right c -> pure c
  mflags <- hieBiosFlags hieBiosLogger cradle projectRoot entryFile
  case mflags of
    Left e -> exitWithMsg e
    Right HieBiosFlags{..} -> do
      let defaultRunConf = RunDebuggerSettings
            { supportsANSIStyling = True
            , supportsANSIHyperlinks = False
            }
      let finalGhcInvocation = ghcInvocation ++ extraGhcArgs
      runDebugger stdout rootDir componentDir libdir units finalGhcInvocation entryFile defaultRunConf $
        fmap fst $
          evalRWST (runInputT (setComplete noCompletion defaultSettings) act)
                   (entryFile, entryPoint, entryArgs) Nothing
  where
    exitWithMsg str = do
      putStrLn str
      exitWith (ExitFailure 33)

  --   completeF = completeWordWithPrev Nothing filenameWordBreakChars $
  --     \(reverse -> previous) word -> do
  --       let comp_words = words previous ++ [word]
  --           comp_cword = length comp_words
  --       case execParserPure parserPrefs cmdParserInfo
  --           ("--bash-completion-index":show comp_cword:
  --             concat (zipWith (\fl a -> [fl, show a]) (repeat "--bash-completion-word") comp_words)) of
  --         CompletionInvoked CompletionResult{execCompletion} ->
  --           map simpleCompletion . words <$> liftIO (execCompletion "")
  --         _ -> return []

-- | Run the interactive command-line debugger
debugInteractive :: Recorder (WithSeverity InteractiveLog) -> InteractiveDM ()
debugInteractive recorder = withInterrupt loop
  where
    debugRec = cmapWithSev DebuggerLog recorder
    loop = handleInterrupt loop $ do
      minput <- getInputLine "(hdb) "
      case minput of
        Nothing -> outputStrLn "Exiting..." >> liftIO (exitWith ExitSuccess)
        Just "" -> do
          lift get >>= \case
            Nothing -> return ()
            Just (cmd :: Command) -> do
              out <- lift . lift $ execute debugRec cmd -- repeat last command
              printResponse debugRec out
        Just input -> do
          mcmd <- parseCmd input
          lift $ put mcmd
          case mcmd of
            Nothing -> return ()
            Just cmd -> do
              out <- lift . lift $ execute debugRec cmd
              printResponse debugRec out
      loop

--------------------------------------------------------------------------------
-- Printing
--------------------------------------------------------------------------------

printResponse :: Recorder (WithSeverity DebuggerLog) -> Response -> InteractiveDM ()
printResponse recd = \case
  DidEval er -> outputStrLn $ show er
  DidSetBreakpoint bf       -> outputStrLn $ show bf
  DidRemoveBreakpoint bf    -> outputStrLn $ show bf
  DidGetBreakpoints mb_span -> outputStrLn $ show mb_span
  DidClearBreakpoints -> outputStrLn "Cleared all breakpoints."
  DidContinue er -> outputStrLn $ show er
  DidStep er -> printEvalResult recd er
  DidExec er -> outputStrLn $ show er
  GotStacktrace stackframes -> outputStrLn $ show stackframes
  GotScopes scopeinfos -> outputStrLn $ show scopeinfos
  GotVariables vis -> outputStrLn $ show vis -- (Either VarInfo [VarInfo])
  Aborted str -> outputStrLn ("Aborted: " ++ str)
  Initialised -> pure ()

printEvalResult :: Recorder (WithSeverity DebuggerLog) -> EvalResult -> InteractiveDM ()
printEvalResult recd EvalStopped{breakId} = do
  out <- lift . lift $ execute recd GetScopes
  printResponse recd out
printEvalResult _ er = outputStrLn $ show er

--------------------------------------------------------------------------------
-- Command parser
--------------------------------------------------------------------------------

breakpointParser :: Parser Breakpoint
breakpointParser =
  ( ModuleBreak
  <$> argument str
      ( metavar "PATH" -- todo: accept module breaks using module name
     <> help "Path to module to break at" )
  <*> argument auto
      ( metavar "LINE_NUM"
     <> help "The line number to break at" )
  <*> optional (argument auto
      ( metavar "COLUMN_NUM"
     <> help "The column number to break at" ))
  )
  <|>
  ( FunctionBreak
    <$> option str
      ( long "name"
     <> short 'n'
     <> metavar "FUNCTION_NAME"
     <> help "Set a breakpoint using the function name" )
  )
  <|>
  ( flag' OnExceptionsBreak ( long "exceptions" )
  )
  <|>
  ( flag' OnUncaughtExceptionsBreak ( long "error" )
  )

runParser :: FilePath -> String -> [String] -> Parser Command
runParser entryFile entryPoint entryArgs =
  -- --entry <name> with some args
  -- (DebugExecution <$> parseEntry <*> parseSomeArgs)
  -- --entry <name> without any args
  -- <|> (DebugExecution <$> parseEntry <*> pure [])
  -- just some args
  (DebugExecution (mkEntry entryPoint) entryFile <$> parseSomeArgs)
  -- just "run"
  <|> (pure $ DebugExecution (mkEntry entryPoint) entryFile entryArgs)
  where
    parseEntry =
      fmap mkEntry $
      option str
        ( long "entry"
        <> short 'e'
        <> metavar "FUNCTION_NAME"
        <> help "Run with this entry point"
        )
    parseSomeArgs =
      some ( argument str
        ( metavar "ARGS" <> help "Arguments to pass to the entry point. If empty, the arguments given at the debugger invocation are used." ) )
    mkEntry entry
      | entry == "main" = MainEntry Nothing
      | otherwise = FunctionEntry entryPoint

-- | Combined parser for 'Command'
cmdParser :: FilePath -> String -> [String] -> Parser Command
cmdParser entryFile entryPoint entryArgs = hsubparser
  ( Options.Applicative.command "break"
    ( info (SetBreakpoint <$> breakpointParser)
      ( progDesc "Set a breakpoint" ) )
  <>
    Options.Applicative.command "delete"
    ( info (DelBreakpoint <$> breakpointParser)
      ( progDesc "Delete a breakpoint" ) )
  <>
    Options.Applicative.command "run"
    ( info (runParser entryFile entryPoint entryArgs)
      ( progDesc "Run the debuggee" ) )
  <>
    Options.Applicative.command "next"
    ( info (pure DoStepLocal)
      ( progDesc "Step over to the next line" ) )
  <>
    Options.Applicative.command "step"
    ( info (pure DoSingleStep)
      ( progDesc "Step-in to the next immediate location" ) )
  <>
    Options.Applicative.command "finish"
    ( info (pure DoStepOut)
      ( progDesc "Step-out of the current function into the caller/its continuation" ) )
  <>
    Options.Applicative.command "continue"
    ( info (pure DoContinue)
      ( progDesc "Continue executing from the current breakpoint" ) )
  <>
    Options.Applicative.command "print"
    ( info (DoEval . unwords <$> many (argument str ( metavar "EXPRESSION"
     <> help "Expression to evaluate in the current context" )))
      ( progDesc "Evaluate an expression in the current context" ) )
  )

-- | Main parser info
cmdParserInfo :: FilePath -> String -> [String] -> ParserInfo Command
cmdParserInfo entryFile entryPoint entryArgs = info (cmdParser entryFile entryPoint entryArgs)
  ( fullDesc )

-- | Parse command line arguments
parseCmd :: String -> InteractiveDM (Maybe Command)
parseCmd input = do
  (entryFile, entryPoint, entryArgs) <- lift ask
  let
    res = execParserPure
     parserPrefs
     (cmdParserInfo entryFile entryPoint entryArgs)
     (words input)
   in case res of
    Success x ->
      return (Just x)
    Failure bad ->
      let (msg, _exit) = renderFailure bad "(hdb)"
       in outputStrLn msg >> pure Nothing
    _ -> outputStrLn "Unsupported command parsing mode" >> pure Nothing

parserPrefs = prefs (disambiguate <> showHelpOnError <> showHelpOnEmpty)