--
-- Haddock - A Haskell Documentation Tool
--
-- (c) Simon Marlow 2003
-- 
-- Ported to use the GHC API by David Waern during "Summer of Code" 2006
--


module Main (main) where


import Haddock.Backends.Html
import Haddock.Backends.Hoogle
import Haddock.Interface
import Haddock.Types
import Haddock.Version
import Haddock.InterfaceFile
import Haddock.Exception
import Haddock.Options
import Haddock.GHC
import Haddock.Utils
import Paths_haddock

import Control.Monad
#if __GLASGOW_HASKELL__ >= 609
import Control.OldException
import qualified Control.Exception as NewException
#else
import Control.Exception
#endif
import Data.Dynamic
import Data.Maybe
import Data.IORef
import qualified Data.Map as Map
import System.IO
import System.Exit
import System.Environment

import GHC
import GHC.Paths
import DynFlags
import Bag
import ErrUtils
#if __GLASGOW_HASKELL__ >= 609
import Panic (handleGhcException)
import Util
#else
import Util hiding (handle)
#endif


--------------------------------------------------------------------------------
-- Exception handling
--------------------------------------------------------------------------------


handleTopExceptions = 
  handleNormalExceptions . handleHaddockExceptions . handleGhcExceptions


handleNormalExceptions inner =
  handle (\exception -> do
    hFlush stdout    
    case exception of
      AsyncException StackOverflow -> do
        putStrLn "stack overflow: use -g +RTS -K<size> to increase it"
        exitFailure
      ExitException code -> exitWith code
      _other -> do
        putStrLn ("haddock: internal Haddock or GHC error: " ++ show exception)
        exitFailure
  ) inner


handleHaddockExceptions inner = 
#if __GLASGOW_HASKELL__ >= 609
  NewException.catches inner [NewException.Handler handler]
#else
  handleDyn handler inner
#endif
  where
    handler (e::HaddockException) = do
      putStrLn $ "haddock: " ++ (show e)
      exitFailure


handleGhcExceptions inner = 
  -- compilation errors: messages with locations attached
#if __GLASGOW_HASKELL__ >= 609
  handleErrMsg (\e -> do
#else
 handleDyn (\e -> do
#endif
    putStrLn "haddock: Compilation error(s):"
    printBagOfErrors defaultDynFlags (unitBag e)
    exitFailure
  ) $

  -- error messages propagated as exceptions
#if __GLASGOW_HASKELL__ >= 609
  handleGhcException (\e -> do
#else
  handleDyn (\e -> do
#endif
    hFlush stdout
    case e of
      PhaseFailed _ code -> exitWith code
      Interrupted -> exitFailure
      _ -> do 
        print (e :: GhcException)
        exitFailure
  ) inner


-------------------------------------------------------------------------------
-- Top level
-------------------------------------------------------------------------------


main :: IO ()
main = handleTopExceptions $ do

  -- parse command-line flags and handle some of them initially
  args <- getArgs
  (flags, fileArgs) <- parseHaddockOpts args
  handleEasyFlags flags fileArgs

  let renderStep packages interfaces = do 
        updateHTMLXRefs packages
        let ifaceFiles = map fst packages
            installedIfaces = concatMap ifInstalledIfaces ifaceFiles
        render flags interfaces installedIfaces

  if not (null fileArgs)
    then do

      let libDir
            | Just dir <- getGhcLibDir flags = dir
            | otherwise = libdir -- from GHC.Paths

      -- initialize GHC
      (session, dynflags) <- startGhc libDir (ghcFlags flags)

      -- get packages supplied with --read-interface
      packages <- readInterfaceFiles (Just session) (ifacePairs flags)

      -- typecheck argument modules using GHC
      modules <- typecheckFiles session fileArgs

      -- combine the link envs of the external packages into one
      let extLinks = Map.unions (map (ifLinkEnv . fst) packages)

      -- create the interfaces -- this is the core part of Haddock
      let (interfaces, homeLinks, messages) = createInterfaces modules extLinks flags
      mapM_ putStrLn messages

      -- render the interfaces
      renderStep packages interfaces
 
      -- last but not least, dump the interface file
      dumpInterfaceFile (map toInstalledIface interfaces) homeLinks flags

    else do
      -- get packages supplied with --read-interface
      packages <- readInterfaceFiles Nothing (ifacePairs flags)

      -- render even though there are no input files (usually contents/index)
      renderStep packages []


-------------------------------------------------------------------------------
-- Rendering
-------------------------------------------------------------------------------


-- | Render the interfaces with whatever backend is specified in the flags 
render :: [Flag] -> [Interface] -> [InstalledInterface] -> IO ()
render flags interfaces installedIfaces = do
  let
    title = case [str | Flag_Heading str <- flags] of
		[] -> ""
		(t:_) -> t

    maybe_source_urls = (listToMaybe [str | Flag_SourceBaseURL   str <- flags]
                        ,listToMaybe [str | Flag_SourceModuleURL str <- flags]
                        ,listToMaybe [str | Flag_SourceEntityURL str <- flags])

    maybe_wiki_urls = (listToMaybe [str | Flag_WikiBaseURL   str <- flags]
                      ,listToMaybe [str | Flag_WikiModuleURL str <- flags]
                      ,listToMaybe [str | Flag_WikiEntityURL str <- flags])

    verbose = Flag_Verbose `elem` flags

  libdir <- case [str | Flag_Lib str <- flags] of
		[] -> getDataDir -- provided by Cabal
		fs -> return (last fs)

  let css_file = case [str | Flag_CSS str <- flags] of
			[] -> Nothing
			fs -> Just (last fs)

  odir <- case [str | Flag_OutputDir str <- flags] of
		[] -> return "."
		fs -> return (last fs)

  let 
    maybe_contents_url = 
      case [url | Flag_UseContents url <- flags] of
        [] -> Nothing
        us -> Just (last us)

    maybe_index_url = 
      case [url | Flag_UseIndex url <- flags] of
        [] -> Nothing
        us -> Just (last us)

    maybe_html_help_format =
      case [hhformat | Flag_HtmlHelp hhformat <- flags] of
        []      -> Nothing
        formats -> Just (last formats)

  prologue <- getPrologue flags

  let 
    -- visible home-module interfaces
    visibleIfaces = [ m | m <- interfaces, OptHide `notElem` (ifaceOptions m) ]

    -- *all* visible interfaces including external package modules
    allVisibleIfaces = map toInstalledIface visibleIfaces
                       ++ installedIfaces
    
    packageMod       = ifaceMod (head visibleIfaces)
    packageStr       = Just (modulePackageString packageMod)
    (pkgName,pkgVer) = modulePackageInfo packageMod

 
  when (Flag_GenIndex `elem` flags) $ do
    ppHtmlIndex odir title packageStr maybe_html_help_format
                maybe_contents_url maybe_source_urls maybe_wiki_urls
                allVisibleIfaces
    copyHtmlBits odir libdir css_file
        
  when (Flag_GenContents `elem` flags && Flag_GenIndex `elem` flags) $ do
    ppHtmlHelpFiles title packageStr visibleIfaces odir maybe_html_help_format []

  when (Flag_GenContents `elem` flags) $ do
    ppHtmlContents odir title packageStr maybe_html_help_format
	                 maybe_index_url maybe_source_urls maybe_wiki_urls
	                 allVisibleIfaces True prologue
    copyHtmlBits odir libdir css_file

  when (Flag_Html `elem` flags) $ do
    ppHtml title packageStr visibleIfaces odir
                prologue maybe_html_help_format
                maybe_source_urls maybe_wiki_urls
                maybe_contents_url maybe_index_url
    copyHtmlBits odir libdir css_file

  when (Flag_Hoogle `elem` flags) $ do
    ppHoogle pkgName pkgVer visibleIfaces odir

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


readInterfaceFiles :: Maybe Session -> [(FilePath, FilePath)] ->
                      IO [(InterfaceFile, FilePath)]
readInterfaceFiles session pairs = do
  mbPackages <- mapM tryReadIface pairs
  return (catMaybes mbPackages)
  where
    -- try to read an interface, warn if we can't
    tryReadIface (html, iface) = do
      eIface <- readInterfaceFile session iface
      case eIface of
        Left err -> do
          putStrLn ("Warning: Cannot read " ++ iface ++ ":")
          putStrLn ("   " ++ show err)
          putStrLn "Skipping this interface."
          return Nothing
        Right iface -> return $ Just (iface, html)


dumpInterfaceFile :: [InstalledInterface] -> LinkEnv -> [Flag] -> IO ()
dumpInterfaceFile ifaces homeLinks flags = 
  case [str | Flag_DumpInterface str <- flags] of
    [] -> return ()
    fs -> let filename = last fs in writeInterfaceFile filename ifaceFile
  where 
    ifaceFile = InterfaceFile {
        ifInstalledIfaces = ifaces,
        ifLinkEnv         = homeLinks
      }


-------------------------------------------------------------------------------
-- Misc
-------------------------------------------------------------------------------


getGhcLibDir flags =
  case [ dir | Flag_GhcLibDir dir <- flags ] of
    [] -> Nothing
    xs -> Just $ last xs


handleEasyFlags flags fileArgs = do
  usage <- getUsage

  when (Flag_Help       `elem` flags) (bye usage)
  when (Flag_Version    `elem` flags) byeVersion
  when (Flag_GhcVersion `elem` flags) byeGhcVersion

  when ((Flag_GenIndex `elem` flags || Flag_GenContents `elem` flags)
        && Flag_Html `elem` flags) $
    throwE ("-h 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"

    byeGhcVersion = bye $ 
      (fromJust $ lookup "Project version" $ compilerInfo) ++ "\n"


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


getPrologue :: [Flag] -> IO (Maybe (HsDoc RdrName))
getPrologue flags
  = case [filename | Flag_Prologue filename <- flags ] of
	[] -> return Nothing 
	[filename] -> do
	   str <- readFile filename
	   case parseHaddockComment str of
		Left err -> throwE err
		Right doc -> return (Just doc)
	_otherwise -> throwE "multiple -p/--prologue options"