    -----------------------------------------------------------------------------
    -- |
    -- Module      :  Distribution.Simple.NHC
    -- Copyright   :  Isaac Jones 2003-2006
    --                Duncan Coutts 2009
    --
    -- Maintainer  :  cabal-devel@haskell.org
    -- Portability :  portable
    --
    -- This module contains most of the NHC-specific code for configuring, building
    -- and installing packages.

    {- Copyright (c) 2003-2005, Isaac Jones
    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:

        * Redistributions of source code must retain the above copyright
          notice, this list of conditions and the following disclaimer.

        * Redistributions in binary form must reproduce the above
          copyright notice, this list of conditions and the following
          disclaimer in the documentation and/or other materials provided
          with the distribution.

        * Neither the name of Isaac Jones nor the names of other
          contributors may be used to endorse or promote products derived
          from this software without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -}

    module Distribution.Simple.NHC (
        configure,
        getInstalledPackages,
        buildLib,
        buildExe,
        installLib,
        installExe,
      ) where

    import Distribution.Package
             ( PackageName, PackageIdentifier(..), InstalledPackageId(..)
             , packageId, packageName )
    import Distribution.InstalledPackageInfo
             ( InstalledPackageInfo
             , InstalledPackageInfo_( InstalledPackageInfo, installedPackageId
                                    , sourcePackageId )
             , emptyInstalledPackageInfo, parseInstalledPackageInfo )
    import Distribution.PackageDescription
            ( PackageDescription(..), BuildInfo(..), Library(..), Executable(..)
            , hcOptions, usedExtensions )
    import Distribution.ModuleName (ModuleName)
    import qualified Distribution.ModuleName as ModuleName
    import Distribution.Simple.LocalBuildInfo
            ( LocalBuildInfo(..), ComponentLocalBuildInfo(..) )
    import Distribution.Simple.BuildPaths
            ( mkLibName, objExtension, exeExtension )
    import Distribution.Simple.Compiler
             ( CompilerFlavor(..), CompilerId(..), Compiler(..)
             , Flag, languageToFlags, extensionsToFlags
             , PackageDB(..), PackageDBStack )
    import qualified Distribution.Simple.PackageIndex as PackageIndex
    import Distribution.Simple.PackageIndex (PackageIndex)
    import Language.Haskell.Extension
             ( Language(Haskell98), Extension(..) )
    import Distribution.Simple.Program
             ( ProgramConfiguration, userMaybeSpecifyPath, programPath
             , requireProgram, requireProgramVersion, lookupProgram
             , nhcProgram, hmakeProgram, ldProgram, arProgram
             , rawSystemProgramConf )
    import Distribution.Simple.Utils
            ( die, info, findFileWithExtension, findModuleFiles
            , installOrdinaryFile, installExecutableFile, installOrdinaryFiles
            , createDirectoryIfMissingVerbose, withUTF8FileContents )
    import Distribution.Version
            ( Version(..), orLaterVersion )
    import Distribution.Verbosity
    import Distribution.Text
             ( display, simpleParse )
    import Distribution.ParseUtils
             ( ParseResult(..) )

    import System.FilePath
            ( (</>), (<.>), normalise, takeDirectory, dropExtension )
    import System.Directory
             ( doesFileExist, doesDirectoryExist, getDirectoryContents
             , removeFile, getHomeDirectory )

    import Data.Char ( toLower )
    import Data.List ( nub )
    import Data.Maybe    ( catMaybes )
    import Data.Monoid   ( Monoid(..) )
    import Control.Monad ( when, unless )
    import Distribution.Compat.Exception

    -- -----------------------------------------------------------------------------
    -- Configuring

    configure :: Verbosity -> Maybe FilePath -> Maybe FilePath
              -> ProgramConfiguration -> IO (Compiler, ProgramConfiguration)
    configure verbosity hcPath _hcPkgPath conf = do

      (_nhcProg, nhcVersion, conf') <-
        requireProgramVersion verbosity nhcProgram
          (orLaterVersion (Version [1,20] []))
          (userMaybeSpecifyPath "nhc98" hcPath conf)

      (_hmakeProg, _hmakeVersion, conf'') <-
        requireProgramVersion verbosity hmakeProgram
         (orLaterVersion (Version [3,13] [])) conf'
      (_ldProg, conf''')   <- requireProgram verbosity ldProgram conf''
      (_arProg, conf'''')  <- requireProgram verbosity arProgram conf'''

      --TODO: put this stuff in a monad so we can say just:
      -- requireProgram hmakeProgram (orLaterVersion (Version [3,13] []))
      -- requireProgram ldProgram anyVersion
      -- requireProgram ldPrograrProgramam anyVersion
      -- unless (null (cSources bi)) $ requireProgram ccProgram anyVersion

      let comp = Compiler {
            compilerId         = CompilerId NHC nhcVersion,
            compilerLanguages  = nhcLanguages,
            compilerExtensions = nhcLanguageExtensions
          }
      return (comp, conf'''')

    nhcLanguages :: [(Language, Flag)]
    nhcLanguages = [(Haskell98, "-98")]

    -- | The flags for the supported extensions
    nhcLanguageExtensions :: [(Extension, Flag)]
    nhcLanguageExtensions =
        -- NHC doesn't enforce the monomorphism restriction at all.
        -- TODO: pattern guards in 1.20
        [(NoMonomorphismRestriction, "")
        ,(ForeignFunctionInterface,  "")
        ,(ExistentialQuantification, "")
        ,(EmptyDataDecls,            "")
        ,(NamedFieldPuns,            "-puns")
        ,(CPP,                       "-cpp")
        ]

    getInstalledPackages :: Verbosity -> PackageDBStack -> ProgramConfiguration
                         -> IO PackageIndex
    getInstalledPackages verbosity packagedbs conf = do
      homedir      <- getHomeDirectory
      (nhcProg, _) <- requireProgram verbosity nhcProgram conf
      let bindir = takeDirectory (programPath nhcProg)
          incdir = takeDirectory bindir </> "include" </> "nhc98"
          dbdirs = nub (concatMap (packageDbPaths homedir incdir) packagedbs)
      indexes  <- mapM getIndividualDBPackages dbdirs
      return $! mconcat indexes

      where
        getIndividualDBPackages :: FilePath -> IO PackageIndex
        getIndividualDBPackages dbdir = do
          pkgdirs <- getPackageDbDirs dbdir
          pkgs    <- sequence [ getInstalledPackage pkgname pkgdir
                              | (pkgname, pkgdir) <- pkgdirs ]
          let pkgs' = map setInstalledPackageId (catMaybes pkgs)
          return (PackageIndex.fromList pkgs')

    packageDbPaths :: FilePath -> FilePath -> PackageDB -> [FilePath]
    packageDbPaths _home incdir db = case db of
      GlobalPackageDB        -> [ incdir </> "packages" ]
      UserPackageDB          -> [] --TODO any standard per-user db?
      SpecificPackageDB path -> [ path ]

    getPackageDbDirs :: FilePath -> IO [(PackageName, FilePath)]
    getPackageDbDirs dbdir = do
      dbexists <- doesDirectoryExist dbdir
      if not dbexists
        then return []
        else do
          entries  <- getDirectoryContents dbdir
          pkgdirs  <- sequence
            [ do pkgdirExists <- doesDirectoryExist pkgdir
                 return (pkgname, pkgdir, pkgdirExists)
            | (entry, Just pkgname) <- [ (entry, simpleParse entry)
                                       | entry <- entries ]
            , let pkgdir = dbdir </> entry ]
          return [ (pkgname, pkgdir) | (pkgname, pkgdir, True) <- pkgdirs ]

    getInstalledPackage :: PackageName -> FilePath -> IO (Maybe InstalledPackageInfo)
    getInstalledPackage pkgname pkgdir = do
      let pkgconfFile = pkgdir </> "package.conf"
      pkgconfExists <- doesFileExist pkgconfFile

      let cabalFile = pkgdir <.> "cabal"
      cabalExists <- doesFileExist cabalFile

      case () of
        _ | pkgconfExists -> getFullInstalledPackageInfo pkgname pkgconfFile
          | cabalExists   -> getPhonyInstalledPackageInfo pkgname cabalFile
          | otherwise     -> return Nothing

    getFullInstalledPackageInfo :: PackageName -> FilePath
                                -> IO (Maybe InstalledPackageInfo)
    getFullInstalledPackageInfo pkgname pkgconfFile =
      withUTF8FileContents pkgconfFile $ \contents ->
        case parseInstalledPackageInfo contents of
          ParseOk _ pkginfo | packageName pkginfo == pkgname
                            -> return (Just pkginfo)
          _                 -> return Nothing

    -- | This is a backup option for existing versions of nhc98 which do not supply
    -- proper installed package info files for the bundled libs. Instead we look
    -- for the .cabal file and extract the package version from that.
    -- We don't know any other details for such packages, in particular we pretend
    -- that they have no dependencies.
    --
    getPhonyInstalledPackageInfo :: PackageName -> FilePath
                                 -> IO (Maybe InstalledPackageInfo)
    getPhonyInstalledPackageInfo pkgname pathsModule = do
      content <- readFile pathsModule
      case extractVersion content of
        Nothing      -> return Nothing
        Just version -> return (Just pkginfo)
          where
            pkgid   = PackageIdentifier pkgname version
            pkginfo = emptyInstalledPackageInfo { sourcePackageId = pkgid }
      where
        -- search through the .cabal file, looking for a line like:
        --
        -- > version: 2.0
        --
        extractVersion :: String -> Maybe Version
        extractVersion content =
          case catMaybes (map extractVersionLine (lines content)) of
            [version] -> Just version
            _         -> Nothing
        extractVersionLine :: String -> Maybe Version
        extractVersionLine line =
          case words line of
            [versionTag, ":", versionStr]
              | map toLower versionTag == "version"  -> simpleParse versionStr
            [versionTag,      versionStr]
              | map toLower versionTag == "version:" -> simpleParse versionStr
            _                                        -> Nothing

    -- Older installed package info files did not have the installedPackageId
    -- field, so if it is missing then we fill it as the source package ID.
    setInstalledPackageId :: InstalledPackageInfo -> InstalledPackageInfo
    setInstalledPackageId pkginfo@InstalledPackageInfo {
                            installedPackageId = InstalledPackageId "",
                            sourcePackageId    = pkgid
                          }
                        = pkginfo {
                            --TODO use a proper named function for the conversion
                            -- from source package id to installed package id
                            installedPackageId = InstalledPackageId (display pkgid)
                          }
    setInstalledPackageId pkginfo = pkginfo

    -- -----------------------------------------------------------------------------
    -- Building

    -- |FIX: For now, the target must contain a main module.  Not used
    -- ATM. Re-add later.
    buildLib :: Verbosity -> PackageDescription -> LocalBuildInfo
                          -> Library            -> ComponentLocalBuildInfo -> IO ()
    buildLib verbosity pkg_descr lbi lib clbi = do
      let conf = withPrograms lbi
          Just nhcProg = lookupProgram nhcProgram conf
      let bi = libBuildInfo lib
          modules = exposedModules lib ++ otherModules bi
          -- Unsupported extensions have already been checked by configure
          languageFlags = languageToFlags (compiler lbi) (defaultLanguage bi)
                       ++ extensionsToFlags (compiler lbi) (usedExtensions bi)
      inFiles <- getModulePaths lbi bi modules
      let targetDir = buildDir lbi
          srcDirs  = nub (map takeDirectory inFiles)
          destDirs = map (targetDir </>) srcDirs
      mapM_ (createDirectoryIfMissingVerbose verbosity True) destDirs
      rawSystemProgramConf verbosity hmakeProgram conf $
           ["-hc=" ++ programPath nhcProg]
        ++ nhcVerbosityOptions verbosity
        ++ ["-d", targetDir, "-hidir", targetDir]
        ++ maybe [] (hcOptions NHC . libBuildInfo)
                               (library pkg_descr)
        ++ languageFlags
        ++ concat [ ["-package", display (packageName pkgid) ]
                  | (_, pkgid) <- componentPackageDeps clbi ]
        ++ inFiles
    {-
      -- build any C sources
      unless (null (cSources bi)) $ do
         info verbosity "Building C Sources..."
         let commonCcArgs = (if verbosity >= deafening then ["-v"] else [])
                         ++ ["-I" ++ dir | dir <- includeDirs bi]
                         ++ [opt | opt <- ccOptions bi]
                         ++ (if withOptimization lbi then ["-O2"] else [])
         flip mapM_ (cSources bi) $ \cfile -> do
           let ofile = targetDir </> cfile `replaceExtension` objExtension
           createDirectoryIfMissingVerbose verbosity True (takeDirectory ofile)
           rawSystemProgramConf verbosity hmakeProgram conf
             (commonCcArgs ++ ["-c", cfile, "-o", ofile])
    -}
      -- link:
      info verbosity "Linking..."
      let --cObjs = [ targetDir </> cFile `replaceExtension` objExtension
          --        | cFile <- cSources bi ]
          libFilePath = targetDir </> mkLibName (packageId pkg_descr)
          hObjs = [ targetDir </> ModuleName.toFilePath m <.> objExtension
                  | m <- modules ]

      unless (null hObjs {-&& null cObjs-}) $ do
        -- first remove library if it exists
        removeFile libFilePath `catchIO` \_ -> return ()

        let arVerbosity | verbosity >= deafening = "v"
                        | verbosity >= normal = ""
                        | otherwise = "c"

        rawSystemProgramConf verbosity arProgram (withPrograms lbi) $
             ["q"++ arVerbosity, libFilePath]
          ++ hObjs
    --    ++ cObjs

    -- | Building an executable for NHC.
    buildExe :: Verbosity -> PackageDescription -> LocalBuildInfo
                          -> Executable         -> ComponentLocalBuildInfo -> IO ()
    buildExe verbosity pkg_descr lbi exe clbi = do
      let conf = withPrograms lbi
          Just nhcProg = lookupProgram nhcProgram conf
      when (dropExtension (modulePath exe) /= exeName exe) $
        die $ "hmake does not support exe names that do not match the name of "
           ++ "the 'main-is' file. You will have to rename your executable to "
           ++ show (dropExtension (modulePath exe))
      let bi = buildInfo exe
          modules = otherModules bi
          -- Unsupported extensions have already been checked by configure
          languageFlags = languageToFlags (compiler lbi) (defaultLanguage bi)
                       ++ extensionsToFlags (compiler lbi) (usedExtensions bi)
      inFiles <- getModulePaths lbi bi modules
      let targetDir = buildDir lbi </> exeName exe
          exeDir    = targetDir </> (exeName exe ++ "-tmp")
          srcDirs   = nub (map takeDirectory (modulePath exe : inFiles))
          destDirs  = map (exeDir </>) srcDirs
      mapM_ (createDirectoryIfMissingVerbose verbosity True) destDirs
      rawSystemProgramConf verbosity hmakeProgram conf $
           ["-hc=" ++ programPath nhcProg]
        ++ nhcVerbosityOptions verbosity
        ++ ["-d", targetDir, "-hidir", targetDir]
        ++ maybe [] (hcOptions NHC . libBuildInfo)
                               (library pkg_descr)
        ++ languageFlags
        ++ concat [ ["-package", display (packageName pkgid) ]
                  | (_, pkgid) <- componentPackageDeps clbi ]
        ++ inFiles
        ++ [exeName exe]

    nhcVerbosityOptions :: Verbosity -> [String]
    nhcVerbosityOptions verbosity
         | verbosity >= deafening = ["-v"]
         | verbosity >= normal    = []
         | otherwise              = ["-q"]

    --TODO: where to put this? it's duplicated in .Simple too
    getModulePaths :: LocalBuildInfo -> BuildInfo -> [ModuleName] -> IO [FilePath]
    getModulePaths lbi bi modules = sequence
       [ findFileWithExtension ["hs", "lhs"] (buildDir lbi : hsSourceDirs bi)
           (ModuleName.toFilePath module_) >>= maybe (notFound module_) (return . normalise)
       | module_ <- modules ]
       where notFound module_ = die $ "can't find source for module " ++ display module_

    -- -----------------------------------------------------------------------------
    -- Installing

    -- |Install executables for NHC.
    installExe :: Verbosity -- ^verbosity
               -> FilePath  -- ^install location
               -> FilePath  -- ^Build location
               -> (FilePath, FilePath)  -- ^Executable (prefix,suffix)
               -> Executable
               -> IO ()
    installExe verbosity pref buildPref (progprefix,progsuffix) exe
        = do createDirectoryIfMissingVerbose verbosity True pref
             let exeBaseName = exeName exe
                 exeFileName = exeBaseName <.> exeExtension
                 fixedExeFileName = (progprefix ++ exeBaseName ++ progsuffix) <.> exeExtension
             installExecutableFile verbosity
               (buildPref </> exeBaseName </> exeFileName)
               (pref </> fixedExeFileName)

    -- |Install for nhc98: .hi and .a files
    installLib    :: Verbosity -- ^verbosity
                  -> FilePath  -- ^install location
                  -> FilePath  -- ^Build location
                  -> PackageIdentifier
                  -> Library
                  -> IO ()
    installLib verbosity pref buildPref pkgid lib
        = do let bi = libBuildInfo lib
                 modules = exposedModules lib ++ otherModules bi
             findModuleFiles [buildPref] ["hi"] modules
               >>= installOrdinaryFiles verbosity pref
             let libName = mkLibName pkgid
             installOrdinaryFile verbosity (buildPref </> libName) (pref </> libName)