{-# OPTIONS_GHC -Wwarn #-}
{-# LANGUAGE CPP, ScopedTypeVariables, Rank2Types #-}
{-# LANGUAGE LambdaCase #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  Haddock
-- Copyright   :  (c) Simon Marlow 2003-2006,
--                    David Waern  2006-2010,
--                    Mateusz Kowalczyk 2014
-- License     :  BSD-like
--
-- Maintainer  :  haddock@projects.haskell.org
-- Stability   :  experimental
-- Portability :  portable
--
-- Haddock - A Haskell Documentation Tool
--
-- Program entry point and top-level code.
-----------------------------------------------------------------------------
module Haddock (
  haddock,
  haddockWithGhc,
  getGhcDirs,
  readPackagesAndProcessModules,
  withGhc
) where

import Data.Version
import Haddock.Backends.Xhtml
import Haddock.Backends.Xhtml.Themes (getThemes)
import Haddock.Backends.LaTeX
import Haddock.Backends.Hoogle
import Haddock.Interface
import Haddock.Parser
import Haddock.Types
import Haddock.Version
import Haddock.InterfaceFile
import Haddock.Options
import Haddock.Utils

import Control.Monad hiding (forM_)
import Control.Applicative
import Data.Foldable (forM_)
import Data.List (isPrefixOf)
import Control.Exception
import Data.Maybe
import Data.IORef
import qualified Data.Map as Map
import System.IO
import System.Exit

#if defined(mingw32_HOST_OS)
import Foreign
import Foreign.C
import Data.Int
#endif

#ifdef IN_GHC_TREE
import System.FilePath
#else
import qualified GHC.Paths as GhcPaths
import Paths_haddock_api (getDataDir)
import System.Directory (doesDirectoryExist)
#endif

import GHC hiding (verbosity)
import Config
import DynFlags hiding (projectVersion, verbosity)
import StaticFlags (discardStaticFlags)
import Packages
import Panic (handleGhcException)
import Module
import FastString

--------------------------------------------------------------------------------
-- * Exception handling
--------------------------------------------------------------------------------


handleTopExceptions :: IO a -> IO a
handleTopExceptions =
  handleNormalExceptions . handleHaddockExceptions . handleGhcExceptions


-- | Either returns normally or throws an ExitCode exception;
-- all other exceptions are turned into exit exceptions.
handleNormalExceptions :: IO a -> IO a
handleNormalExceptions inner =
  (inner `onException` hFlush stdout)
  `catches`
  [  Handler (\(code :: ExitCode) -> exitWith code)

  ,  Handler (\(ex :: AsyncException) ->
       case ex of
         StackOverflow -> do
           putStrLn "stack overflow: use -g +RTS -K<size> to increase it"
           exitFailure
         _ -> do
           putStrLn ("haddock: " ++ show ex)
           exitFailure)

  ,  Handler (\(ex :: SomeException) -> do
        putStrLn ("haddock: internal error: " ++ show ex)
        exitFailure)
  ]


handleHaddockExceptions :: IO a -> IO a
handleHaddockExceptions inner =
  catches inner [Handler handler]
  where
    handler (e::HaddockException) = do
      putStrLn $ "haddock: " ++ show e
      exitFailure


handleGhcExceptions :: IO a -> IO a
handleGhcExceptions =
  -- error messages propagated as exceptions
  handleGhcException $ \e -> do
    hFlush stdout
    case e of
      PhaseFailed _ code -> exitWith code
      _ -> do
        print (e :: GhcException)
        exitFailure


-------------------------------------------------------------------------------
-- * Top level
-------------------------------------------------------------------------------


-- | Run Haddock with given list of arguments.
--
-- Haddock's own main function is defined in terms of this:
--
-- > main = getArgs >>= haddock
haddock :: [String] -> IO ()
haddock args = haddockWithGhc withGhc args

haddockWithGhc :: (forall a. [Flag] -> Ghc a -> IO a) -> [String] -> IO ()
haddockWithGhc ghc args = handleTopExceptions $ do

  -- Parse command-line flags and handle some of them initially.
  -- TODO: unify all of this (and some of what's in the 'render' function),
  -- into one function that returns a record with a field for each option,
  -- or which exits with an error or help message.
  (flags, files) <- parseHaddockOpts args
  shortcutFlags flags
  qual <- case qualification flags of {Left msg -> throwE msg; Right q -> return q}

  -- inject dynamic-too into flags before we proceed
  flags' <- ghc flags $ do
        df <- getDynFlags
        case lookup "GHC Dynamic" (compilerInfo df) of
          Just "YES" -> return $ Flag_OptGhc "-dynamic-too" : flags
          _ -> return flags

  unless (Flag_NoWarnings `elem` flags) $ do
    forM_ (warnings args) $ \warning -> do
      hPutStrLn stderr warning

  ghc flags' $ do

    dflags <- getDynFlags

    if not (null files) then do
      (packages, ifaces, homeLinks) <- readPackagesAndProcessModules flags files

      -- Dump an "interface file" (.haddock file), if requested.
      forM_ (optDumpInterfaceFile flags) $ \path -> liftIO $ do
        writeInterfaceFile path InterfaceFile {
            ifInstalledIfaces = map toInstalledIface ifaces
          , ifLinkEnv         = homeLinks
          }

      -- Render the interfaces.
      liftIO $ renderStep dflags flags qual packages ifaces

    else do
      when (any (`elem` [Flag_Html, Flag_Hoogle, Flag_LaTeX]) flags) $
        throwE "No input file(s)."

      -- Get packages supplied with --read-interface.
      packages <- liftIO $ readInterfaceFiles freshNameCache (readIfaceArgs flags)

      -- Render even though there are no input files (usually contents/index).
      liftIO $ renderStep dflags flags qual packages []

-- | Create warnings about potential misuse of -optghc
warnings :: [String] -> [String]
warnings = map format . filter (isPrefixOf "-optghc")
  where
    format arg = concat ["Warning: `", arg, "' means `-o ", drop 2 arg, "', did you mean `-", arg, "'?"]


withGhc :: [Flag] -> Ghc a -> IO a
withGhc flags action = do
  libDir <- fmap snd (getGhcDirs flags)

  -- Catches all GHC source errors, then prints and re-throws them.
  let handleSrcErrors action' = flip handleSourceError action' $ \err -> do
        printException err
        liftIO exitFailure

  withGhc' libDir (ghcFlags flags) (\_ -> handleSrcErrors action)


readPackagesAndProcessModules :: [Flag] -> [String]
                              -> Ghc ([(DocPaths, InterfaceFile)], [Interface], LinkEnv)
readPackagesAndProcessModules flags files = do
    -- Get packages supplied with --read-interface.
    packages <- readInterfaceFiles nameCacheFromGhc (readIfaceArgs flags)

    -- Create the interfaces -- this is the core part of Haddock.
    let ifaceFiles = map snd packages
    (ifaces, homeLinks) <- processModules (verbosity flags) files flags ifaceFiles

    return (packages, ifaces, homeLinks)


renderStep :: DynFlags -> [Flag] -> QualOption -> [(DocPaths, InterfaceFile)] -> [Interface] -> IO ()
renderStep dflags flags qual pkgs interfaces = do
  updateHTMLXRefs pkgs
  let
    ifaceFiles = map snd pkgs
    installedIfaces = concatMap ifInstalledIfaces ifaceFiles
    srcMap = Map.fromList [ (ifPackageKey if_, x) | ((_, Just x), if_) <- pkgs ]
  render dflags flags qual interfaces installedIfaces srcMap


-- | Render the interfaces with whatever backend is specified in the flags.
render :: DynFlags -> [Flag] -> QualOption -> [Interface] -> [InstalledInterface] -> SrcMap -> IO ()
render dflags flags qual ifaces installedIfaces srcMap = do

  let
    title                = fromMaybe "" (optTitle flags)
    unicode              = Flag_UseUnicode `elem` flags
    pretty               = Flag_PrettyHtml `elem` flags
    opt_wiki_urls        = wikiUrls          flags
    opt_contents_url     = optContentsUrl    flags
    opt_index_url        = optIndexUrl       flags
    odir                 = outputDir         flags
    opt_latex_style      = optLaTeXStyle     flags

    visibleIfaces    = [ i | i <- ifaces, OptHide `notElem` ifaceOptions i ]

    -- /All/ visible interfaces including external package modules.
    allIfaces        = map toInstalledIface ifaces ++ installedIfaces
    allVisibleIfaces = [ i | i <- allIfaces, OptHide `notElem` instOptions i ]

    pkgMod           = ifaceMod (head ifaces)
    pkgKey           = modulePackageKey pkgMod
    pkgStr           = Just (packageKeyString pkgKey)
    pkgNameVer       = modulePackageInfo dflags flags pkgMod

    (srcBase, srcModule, srcEntity, srcLEntity) = sourceUrls flags
    srcMap' = maybe srcMap (\path -> Map.insert pkgKey path srcMap) srcEntity
    -- TODO: Get these from the interface files as with srcMap
    srcLMap' = maybe Map.empty (\path -> Map.singleton pkgKey path) srcLEntity
    sourceUrls' = (srcBase, srcModule, srcMap', srcLMap')

  libDir   <- getHaddockLibDir flags
  prologue <- getPrologue dflags flags
  themes   <- getThemes libDir flags >>= either bye return

  when (Flag_GenIndex `elem` flags) $ do
    ppHtmlIndex odir title pkgStr
                themes opt_contents_url sourceUrls' opt_wiki_urls
                allVisibleIfaces pretty
    copyHtmlBits odir libDir themes

  when (Flag_GenContents `elem` flags) $ do
    ppHtmlContents dflags odir title pkgStr
                   themes opt_index_url sourceUrls' opt_wiki_urls
                   allVisibleIfaces True prologue pretty
                   (makeContentsQual qual)
    copyHtmlBits odir libDir themes

  when (Flag_Html `elem` flags) $ do
    ppHtml dflags title pkgStr visibleIfaces odir
                prologue
                themes sourceUrls' opt_wiki_urls
                opt_contents_url opt_index_url unicode qual
                pretty
    copyHtmlBits odir libDir themes

  -- TODO: we throw away Meta for both Hoogle and LaTeX right now,
  -- might want to fix that if/when these two get some work on them
  when (Flag_Hoogle `elem` flags) $ do
    case pkgNameVer of
      Nothing -> putStrLn . unlines $
          [ "haddock: Unable to find a package providing module "
            ++ moduleNameString (moduleName pkgMod) ++ ", skipping Hoogle."
          , ""
          , "         Perhaps try specifying the desired package explicitly"
            ++ " using the --package-name"
          , "         and --package-version arguments."
          ]
      Just (PackageName pkgNameFS, pkgVer) ->
          let pkgNameStr | unpackFS pkgNameFS == "main" && title /= [] = title
                         | otherwise = unpackFS pkgNameFS
          in ppHoogle dflags pkgNameStr pkgVer title (fmap _doc prologue)
               visibleIfaces odir

  when (Flag_LaTeX `elem` flags) $ do
    ppLaTeX title pkgStr visibleIfaces odir (fmap _doc prologue) opt_latex_style
                  libDir

-- | From GHC 7.10, this function has a potential to crash with a
-- nasty message such as @expectJust getPackageDetails@ because
-- package name and versions can no longer reliably be extracted in
-- all cases: if the package is not installed yet then this info is no
-- longer available. The @--package-name@ and @--package-version@
-- Haddock flags allow the user to specify this information and it is
-- returned here if present: if it is not present, the error will
-- occur. Nasty but that's how it is for now. Potential TODO.
modulePackageInfo :: DynFlags
                  -> [Flag] -- ^ Haddock flags are checked as they may
                            -- contain the package name or version
                            -- provided by the user which we
                            -- prioritise
                  -> Module -> Maybe (PackageName, Data.Version.Version)
modulePackageInfo dflags flags modu =
    cmdline <|> pkgDb
  where
    cmdline = (,) <$> optPackageName flags <*> optPackageVersion flags
    pkgDb = (\pkg -> (packageName pkg, packageVersion pkg)) <$> lookupPackage dflags (modulePackageKey modu)


-------------------------------------------------------------------------------
-- * Reading and dumping interface files
-------------------------------------------------------------------------------


readInterfaceFiles :: MonadIO m
                   => NameCacheAccessor m
                   -> [(DocPaths, FilePath)]
                   -> m [(DocPaths, InterfaceFile)]
readInterfaceFiles name_cache_accessor pairs = do
  catMaybes `liftM` mapM tryReadIface pairs
  where
    -- try to read an interface, warn if we can't
    tryReadIface (paths, file) =
      readInterfaceFile name_cache_accessor file >>= \case
        Left err -> liftIO $ do
          putStrLn ("Warning: Cannot read " ++ file ++ ":")
          putStrLn ("   " ++ err)
          putStrLn "Skipping this interface."
          return Nothing
        Right f -> return $ Just (paths, f)


-------------------------------------------------------------------------------
-- * Creating a GHC session
-------------------------------------------------------------------------------


-- | Start a GHC session with the -haddock flag set. Also turn off
-- compilation and linking. Then run the given 'Ghc' action.
withGhc' :: String -> [String] -> (DynFlags -> Ghc a) -> IO a
withGhc' libDir flags ghcActs = runGhc (Just libDir) $ do
  dynflags  <- getSessionDynFlags
  dynflags' <- parseGhcFlags (gopt_set dynflags Opt_Haddock) {
    hscTarget = HscNothing,
    ghcMode   = CompManager,
    ghcLink   = NoLink
    }
  let dynflags'' = gopt_unset dynflags' Opt_SplitObjs
  defaultCleanupHandler dynflags'' $ do
      -- ignore the following return-value, which is a list of packages
      -- that may need to be re-linked: Haddock doesn't do any
      -- dynamic or static linking at all!
      _ <- setSessionDynFlags dynflags''
      ghcActs dynflags''
  where
    parseGhcFlags :: MonadIO m => DynFlags -> m DynFlags
    parseGhcFlags dynflags = do
      -- TODO: handle warnings?

      -- NOTA BENE: We _MUST_ discard any static flags here, because we cannot
      -- rely on Haddock to parse them, as it only parses the DynFlags. Yet if
      -- we pass any, Haddock will fail. Since StaticFlags are global to the
      -- GHC invocation, there's also no way to reparse/save them to set them
      -- again properly.
      --
      -- This is a bit of a hack until we get rid of the rest of the remaining
      -- StaticFlags. See GHC issue #8276.
      let flags' = discardStaticFlags flags
      (dynflags', rest, _) <- parseDynamicFlags dynflags (map noLoc flags')
      if not (null rest)
        then throwE ("Couldn't parse GHC options: " ++ unwords flags')
        else return dynflags'

-------------------------------------------------------------------------------
-- * Misc
-------------------------------------------------------------------------------


getHaddockLibDir :: [Flag] -> IO String
getHaddockLibDir flags =
  case [str | Flag_Lib str <- flags] of
    [] -> do
#ifdef IN_GHC_TREE
      getInTreeDir
#else
      d <- getDataDir -- provided by Cabal
      doesDirectoryExist d >>= \exists -> case exists of
        True -> return d
        False -> do
          -- If directory does not exist then we are probably invoking from
          -- ./dist/build/haddock/haddock so we use ./resources as a fallback.
          doesDirectoryExist "resources" >>= \exists_ -> case exists_ of
            True -> return "resources"
            False -> die ("Haddock's resource directory (" ++ d ++ ") does not exist!\n")
#endif
    fs -> return (last fs)


getGhcDirs :: [Flag] -> IO (String, String)
getGhcDirs flags = do
  case [ dir | Flag_GhcLibDir dir <- flags ] of
    [] -> do
#ifdef IN_GHC_TREE
      libDir <- getInTreeDir
      return (ghcPath, libDir)
#else
      return (ghcPath, GhcPaths.libdir)
#endif
    xs -> return (ghcPath, last xs)
  where
#ifdef IN_GHC_TREE
    ghcPath = "not available"
#else
    ghcPath = GhcPaths.ghc
#endif


shortcutFlags :: [Flag] -> IO ()
shortcutFlags flags = do
  usage <- getUsage

  when (Flag_Help             `elem` flags) (bye usage)
  when (Flag_Version          `elem` flags) byeVersion
  when (Flag_InterfaceVersion `elem` flags) (bye (show binaryInterfaceVersion ++ "\n"))
  when (Flag_CompatibleInterfaceVersions `elem` flags)
    (bye (unwords (map show binaryInterfaceVersionCompatibility) ++ "\n"))
  when (Flag_GhcVersion       `elem` flags) (bye (cProjectVersion ++ "\n"))

  when (Flag_PrintGhcPath `elem` flags) $ do
    dir <- fmap fst (getGhcDirs flags)
    bye $ dir ++ "\n"

  when (Flag_PrintGhcLibDir `elem` flags) $ do
    dir <- fmap snd (getGhcDirs flags)
    bye $ dir ++ "\n"

  when (Flag_UseUnicode `elem` flags && Flag_Html `notElem` flags) $
    throwE "Unicode can only be enabled for HTML output."

  when ((Flag_GenIndex `elem` flags || Flag_GenContents `elem` flags)
        && Flag_Html `elem` flags) $
    throwE "-h cannot be used with --gen-index or --gen-contents"

  when ((Flag_GenIndex `elem` flags || Flag_GenContents `elem` flags)
        && Flag_Hoogle `elem` flags) $
    throwE "--hoogle cannot be used with --gen-index or --gen-contents"

  when ((Flag_GenIndex `elem` flags || Flag_GenContents `elem` flags)
        && Flag_LaTeX `elem` flags) $
    throwE "--latex cannot be used with --gen-index or --gen-contents"
  where
    byeVersion = bye $
      "Haddock version " ++ projectVersion ++ ", (c) Simon Marlow 2006\n"
      ++ "Ported to use the GHC API by David Waern 2006-2008\n"


updateHTMLXRefs :: [(DocPaths, InterfaceFile)] -> IO ()
updateHTMLXRefs packages = do
  writeIORef html_xrefs_ref (Map.fromList mapping)
  writeIORef html_xrefs_ref' (Map.fromList mapping')
  where
    mapping = [ (instMod iface, html) | ((html, _), ifaces) <- packages
              , iface <- ifInstalledIfaces ifaces ]
    mapping' = [ (moduleName m, html) | (m, html) <- mapping ]


getPrologue :: DynFlags -> [Flag] -> IO (Maybe (MDoc RdrName))
getPrologue dflags flags =
  case [filename | Flag_Prologue filename <- flags ] of
    [] -> return Nothing
    [filename] -> withFile filename ReadMode $ \h -> do
      hSetEncoding h utf8
      str <- hGetContents h
      return . Just $! parseParas dflags str
    _ -> throwE "multiple -p/--prologue options"


#ifdef IN_GHC_TREE

getInTreeDir :: IO String
getInTreeDir = getExecDir >>= \case
  Nothing -> error "No GhcDir found"
  Just d -> return (d </> ".." </> "lib")


getExecDir :: IO (Maybe String)
#if defined(mingw32_HOST_OS)
getExecDir = try_size 2048 -- plenty, PATH_MAX is 512 under Win32.
  where
    try_size size = allocaArray (fromIntegral size) $ \buf -> do
        ret <- c_GetModuleFileName nullPtr buf size
        case ret of
          0 -> return Nothing
          _ | ret < size -> fmap (Just . dropFileName) $ peekCWString buf
            | otherwise  -> try_size (size * 2)

foreign import stdcall unsafe "windows.h GetModuleFileNameW"
  c_GetModuleFileName :: Ptr () -> CWString -> Word32 -> IO Word32
#else
getExecDir = return Nothing
#endif

#endif
