{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE TupleSections #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE BangPatterns #-}


{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE PartialTypeSignatures #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE NoMonomorphismRestriction #-}
module Refact.Run where

import Language.Haskell.GHC.ExactPrint
import Language.Haskell.GHC.ExactPrint.Print
import Language.Haskell.GHC.ExactPrint.Parsers (parseModuleWithOptions)
import Language.Haskell.GHC.ExactPrint.Utils


import qualified Refact.Types as R
import Refact.Types hiding (SrcSpan)
import Refact.Apply
import Refact.Fixity
import Refact.Utils (toGhcSrcSpan, Module)
import qualified SrcLoc as GHC

import Options.Applicative
import Data.Maybe
import Data.Monoid ( (<>) )
import Control.Monad.Trans.Maybe
import Data.List hiding (find)

import System.IO
import System.IO.Temp
import System.FilePath.Find
import System.Exit
import qualified System.PosixCompat.Files as F

import Control.Monad
import Control.Monad.State
import Control.Monad.Identity

import Paths_apply_refact
import Data.Version

import Debug.Trace

import SrcLoc
import Text.Read
import Data.Char

refactMain :: IO ()
refactMain = do
  o@Options{..} <- execParser optionsWithHelp
  when optionsVersion (putStr ("v" ++ showVersion version) >> exitSuccess)
  unless (isJust optionsTarget || isJust optionsRefactFile)
    (error "Must specify either the target file or the refact file")
  case optionsTarget of
    Nothing ->
      withSystemTempFile "stdin"  (\fp hin -> do
        getContents >>= hPutStrLn hin >> hClose hin
        runPipe o fp)
    Just target -> do
      targetStatus <- F.getFileStatus target
      if F.isDirectory targetStatus
        then findHsFiles target >>= mapM_ (runPipe o)
        else runPipe o target


parseVerbosity :: Monad m => String -> m Verbosity
parseVerbosity s =
  return $ case s of
             "0" -> Silent
             "1" -> Normal
             "2" -> Loud
             _   -> Normal

parsePos :: Monad m => String -> m (Int, Int)
parsePos s =
  case span isDigit s of
    (line, ',':col) ->
      case (,) <$> readMaybe line <*> readMaybe col of
        Just l -> return l
        Nothing -> fail "Invalid input"
    _ -> fail "Invalid input"

data Target = StdIn | File FilePath

data Options = Options
  { optionsTarget   :: Maybe FilePath -- ^ Where to process hints
  , optionsRefactFile :: Maybe FilePath -- ^ The refactorings to process
  , optionsInplace  :: Bool
  , optionsOutput   :: Maybe FilePath -- ^ Whether to overwrite the file inplace
  , optionsVerbosity :: Verbosity
  , optionsStep :: Bool -- ^ Ask before applying each hint
  , optionsDebug :: Bool
  , optionsRoundtrip :: Bool
  , optionsVersion :: Bool
  , optionsPos     :: Maybe (Int, Int)
  }

options :: Parser Options
options =
  Options <$>
    optional (argument str (metavar "TARGET"))
    <*>
    option (Just <$> str)
      (long "refact-file"
      <> value Nothing
      <> help "A file which specifies which refactorings to perform")

    <*>
    switch (long "inplace"
           <> short 'i'
           <> help "Whether to overwrite the target inplace")
    <*>
    optional (strOption (long "output"
                        <> short 'o'
                        <> help "Name of the file to output to"
                        <> metavar "FILE"))
    <*>
    option (str >>= parseVerbosity)
           ( long "verbosity"
           <> short 'v'
           <> value Normal
           <> help "Specify verbosity, 0, 1 or 2. The default is 1 and 0 is silent.")
    <*>
    switch (short 's'
           <> long "step"
           <> help "Ask before applying each refactoring")
    <*>
    switch (long "debug"
           <> help "Output the GHC AST for debugging"
           <> internal)
    <*>
    switch (long "roundtrip"
           <> help "Run ghc-exactprint on the file"
           <> internal)
    <*>
    switch (long "version"
           <> help "Display version number")
    <*>
    option (Just <$> (str >>= parsePos))
           (long "pos"
           <> value Nothing
           <> metavar "<line>,<col>"
           <> help "Apply hints relevant to a specific position")


optionsWithHelp :: ParserInfo Options
optionsWithHelp
  =
    info (helper <*> options)
          ( fullDesc
          <> progDesc "Automatically perform refactorings on haskell source files"
          <> header "refactor" )



-- Given base directory finds all haskell source files
findHsFiles :: FilePath -> IO [FilePath]
findHsFiles = find filterDirectory filterFilename

filterDirectory :: FindClause Bool
filterDirectory =
  p <$> fileName
  where
    p x
      | "." `isPrefixOf` x = False
      | otherwise = True

filterFilename :: FindClause Bool
filterFilename = do
  ext <- extension
  fname <- fileName
  return (ext == ".hs" && p fname)
  where
    p x
      | "Setup.hs" `isInfixOf` x = False
      | otherwise                 = True


-- Pipe


runPipe :: Options -> FilePath  -> IO ()
runPipe Options{..} file = do
  let verb = optionsVerbosity
  when (verb == Loud) (traceM "Parsing module")
  (as, m) <- either (error . show) (uncurry applyFixities)
              <$> parseModuleWithOptions rigidLayout file
  when optionsDebug (putStrLn (showAnnData as 0 m))
  rawhints <- getHints optionsRefactFile
  when (verb == Loud) (traceM "Got raw hints")
  let inp :: [(String, [Refactoring R.SrcSpan])] = read rawhints
      n = length inp
  when (verb == Loud) (traceM $ "Read " ++ show n ++ " hints")
  let noOverlapInp = removeOverlap verb inp
      refacts = (fmap . fmap . fmap) (toGhcSrcSpan file) <$> noOverlapInp

      posFilter (_, rs) =
        case optionsPos of
          Nothing -> True
          Just p  -> any (flip spans p . pos) rs
      filtRefacts = filter posFilter refacts


  when (verb >= Normal) (traceM $ "Applying " ++ show (length (concatMap snd filtRefacts)) ++ " hints")
  when (verb == Loud) (traceM $ show filtRefacts)
  -- need a check here to avoid overlap
  (ares, res) <- if optionsStep
                   then fromMaybe (as, m) <$> runMaybeT (refactoringLoop as m filtRefacts)
                   else return . flip evalState 0 $
                          foldM (uncurry runRefactoring) (as, m) (concatMap snd filtRefacts)
  when (optionsDebug) (putStrLn (showAnnData ares 0 res))
  let output = runIdentity $ exactPrintWithOptions refactOptions res ares
  if optionsInplace && isJust optionsTarget
    then writeFile file output
    else case optionsOutput of
           Nothing -> putStr output
           Just f  -> do
            when (verb == Loud) (traceM $ "Writing result to " ++ f)
            writeFile f output

data LoopOption = LoopOption
                    { desc :: String
                    , perform :: MaybeT IO (Anns, Module) }

refactoringLoop :: Anns -> Module -> [(String, [Refactoring GHC.SrcSpan])]
                -> MaybeT IO (Anns, Module)
refactoringLoop as m [] = return (as, m)
refactoringLoop as m ((_, []): rs) = refactoringLoop as m rs
refactoringLoop as m hints@((hintDesc, rs): rss) =
  do inp <- liftIO $ do
        putStrLn hintDesc
        putStrLn $ "Apply hint [" ++ intercalate ", " (map fst opts) ++ "]"
        -- In case that the input also comes from stdin
        withFile "/dev/tty" ReadMode hGetLine
     case lookup inp opts of
          Just opt   -> perform opt
          Nothing    -> loopHelp
  where
    opts =
      [ ("y", LoopOption "Apply current hint" yAction)
      , ("n", LoopOption "Don't apply the current hint" (refactoringLoop as m rss))
      , ("q", LoopOption "Apply no further hints" (return (as, m)))
      , ("d", LoopOption "Discard previous changes" mzero )
      , ("v", LoopOption "View current file" (liftIO (putStrLn (exactPrint m as))
                                              >> refactoringLoop as m hints))
      , ("?", LoopOption "Show this help menu" loopHelp)]
    loopHelp = do
            liftIO . putStrLn . unlines . map mkLine $ opts
            refactoringLoop as m hints
    mkLine (c, opt) = c ++ " - " ++ desc opt
    -- Force to force bottoms
    yAction =
      let (!r1, !r2) = flip evalState 0 $ foldM (uncurry runRefactoring) (as, m) rs
        in do
          exactPrint r2 r1 `seq` return ()
          refactoringLoop r1 r2 rss


getHints :: Maybe FilePath -> IO String
getHints (Just hintFile) = readFile hintFile
getHints Nothing = getContents