    {-# OPTIONS -cpp #-}
    -----------------------------------------------------------------------------
    -- |
    -- Module      :  Distribution.Simple.Configure
    -- Copyright   :  Isaac Jones 2003-2005
    --
    -- Maintainer  :  Isaac Jones <ijones@syntaxpolice.org>
    -- Stability   :  alpha
    -- Portability :  portable
    --
    -- Explanation: Perform the \"@.\/setup configure@\" action.
    -- Outputs the @dist\/setup-config@ file.

    {- 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.Configure (configure,
                                          writePersistBuildConfig,
                                          getPersistBuildConfig,
                                          checkPersistBuildConfig,
                                          maybeGetPersistBuildConfig,
    --                                      getConfiguredPkgDescr,
                                          localBuildInfoFile,
                                          getInstalledPackages,
    				      configDependency,
                                          configCompiler, configCompilerAux,
    #ifdef DEBUG
                                          hunitTests
    #endif
                                         )
        where

    #if __GLASGOW_HASKELL__ && __GLASGOW_HASKELL__ < 604
    #if __GLASGOW_HASKELL__ < 603
    #include "config.h"
    #else
    #include "ghcconfig.h"
    #endif
    #endif

    import Distribution.Compat.Directory
        ( createDirectoryIfMissing )
    import Distribution.Simple.Compiler
        ( CompilerFlavor(..), Compiler(..), compilerVersion, showCompilerId
        , unsupportedExtensions, PackageDB(..) )
    import Distribution.Package
        ( PackageIdentifier(..), showPackageId )
    import Distribution.PackageDescription
        ( PackageDescription(..), GenericPackageDescription(..)
        , Library(..), Executable(..), BuildInfo(..), finalizePackageDescription
        , HookedBuildInfo, sanityCheckPackage, updatePackageDescription
        , setupMessage, satisfyDependency, hasLibs, allBuildInfo )
    import Distribution.ParseUtils
        ( showDependency )
    import Distribution.Simple.Program
        ( Program(..), ProgramLocation(..), ConfiguredProgram(..)
        , ProgramConfiguration, configureAllKnownPrograms, knownPrograms
        , lookupKnownProgram, requireProgram, pkgConfigProgram
        , rawSystemProgramStdoutConf )
    import Distribution.Simple.Setup
        ( ConfigFlags(..), CopyDest(..) )
    import Distribution.Simple.InstallDirs
        ( InstallDirs(..), InstallDirTemplates(..), defaultInstallDirs
        , toPathTemplate )
    import Distribution.Simple.LocalBuildInfo
        ( LocalBuildInfo(..), distPref, absoluteInstallDirs
        , prefixRelativeInstallDirs )
    import Distribution.Simple.Utils
        ( die, warn, info, createDirectoryIfMissingVerbose )
    import Distribution.Simple.Register
        ( removeInstalledConfig )
    import Distribution.System
        ( os, OS(..), Windows(..) )
    import Distribution.Version
        ( Version(..), Dependency(..), VersionRange(..), showVersion, readVersion
        , showVersionRange, orLaterVersion, withinRange )
    import Distribution.Verbosity
        ( Verbosity, lessVerbose )

    import qualified Distribution.Simple.GHC  as GHC
    import qualified Distribution.Simple.JHC  as JHC
    import qualified Distribution.Simple.NHC  as NHC
    import qualified Distribution.Simple.Hugs as Hugs

    import Control.Monad
        ( when, unless, foldM )
    import Control.Exception as Exception
        ( catch )
    import Data.Char
        ( toLower )
    import Data.List
        ( intersperse, nub, partition, isPrefixOf )
    import Data.Maybe
        ( fromMaybe, isNothing )
    import System.Directory
        ( doesFileExist, getModificationTime )
    import System.Environment
        ( getProgName )
    import System.Exit
        ( ExitCode(..), exitWith )
    import System.FilePath
        ( (</>) )
    import qualified System.Info
        ( os, arch )
    import System.IO
        ( hPutStrLn, stderr, hGetContents, openFile, hClose, IOMode(ReadMode) )
    import Text.PrettyPrint.HughesPJ
        ( comma, punctuate, render, nest, sep )

    import Prelude hiding (catch)

    #ifdef DEBUG
    import Test.HUnit
    #endif

    tryGetConfigStateFile :: (Read a) => FilePath -> IO (Either String a)
    tryGetConfigStateFile filename = do
      e <- doesFileExist filename
      let dieMsg = "error reading " ++ filename ++
                   "; run \"setup configure\" command?\n"
      if (not e) then return $ Left dieMsg else do
        str <- readFileStrict filename
        case reads str of
          [(bi,_)] -> return $ Right bi
          _        -> return $ Left  dieMsg
      where
        readFileStrict name = do
          h <- openFile name ReadMode
          str <- hGetContents h >>= \str -> length str `seq` return str
          hClose h
          return str

    -- internal function
    tryGetPersistBuildConfig :: IO (Either String LocalBuildInfo)
    tryGetPersistBuildConfig = tryGetConfigStateFile localBuildInfoFile

    -- |Read the 'localBuildInfoFile'.  Error if it doesn't exist.  Also
    -- fail if the file containing LocalBuildInfo is older than the .cabal
    -- file, indicating that a re-configure is required.
    getPersistBuildConfig :: IO LocalBuildInfo
    getPersistBuildConfig = do
      lbi <- tryGetPersistBuildConfig
      either die return lbi

    -- |Try to read the 'localBuildInfoFile'.
    maybeGetPersistBuildConfig :: IO (Maybe LocalBuildInfo)
    maybeGetPersistBuildConfig = do
      lbi <- tryGetPersistBuildConfig
      return $ either (const Nothing) Just lbi

    -- |After running configure, output the 'LocalBuildInfo' to the
    -- 'localBuildInfoFile'.
    writePersistBuildConfig :: LocalBuildInfo -> IO ()
    writePersistBuildConfig lbi = do
      createDirectoryIfMissing False distPref
      writeFile localBuildInfoFile (show lbi)

    -- |Check that localBuildInfoFile is up-to-date with respect to the
    -- .cabal file.
    checkPersistBuildConfig :: FilePath -> IO ()
    checkPersistBuildConfig pkg_descr_file = do
      t0 <- getModificationTime pkg_descr_file
      t1 <- getModificationTime localBuildInfoFile
      when (t0 > t1) $
        die (pkg_descr_file ++ " has been changed, please re-configure.")

    -- |@dist\/setup-config@
    localBuildInfoFile :: FilePath
    localBuildInfoFile = distPref </> "setup-config"

    -- -----------------------------------------------------------------------------
    -- * Configuration
    -- -----------------------------------------------------------------------------

    -- |Perform the \"@.\/setup configure@\" action.
    -- Returns the @.setup-config@ file.
    configure :: ( Either GenericPackageDescription PackageDescription
                 , HookedBuildInfo)
              -> ConfigFlags -> IO LocalBuildInfo
    configure (pkg_descr0, pbi) cfg
      = do  let verbosity = configVerbose cfg
                cfg' = cfg { configVerbose = lessVerbose verbosity }

    	setupMessage verbosity "Configuring"
                         (either packageDescription id pkg_descr0)

    	createDirectoryIfMissingVerbose (lessVerbose verbosity) True distPref

    	-- detect compiler
    	(comp, programsConfig) <- configCompilerAux cfg'
            let version = compilerVersion comp
                flavor  = compilerFlavor comp

            -- FIXME: currently only GHC has hc-pkg
            mipkgs <- getInstalledPackages (lessVerbose verbosity) comp
                        (configPackageDB cfg) programsConfig

            (pkg_descr, flags) <- case pkg_descr0 of
                Left ppd ->
                    case finalizePackageDescription
                           (configConfigurationsFlags cfg)
                           mipkgs
                           System.Info.os
                           System.Info.arch
                           (map toLower (show flavor),version)
                           ppd
                    of Right r -> return r
                       Left missing ->
                           die $ "At least the following dependencies are missing:\n"
                             ++ (render . nest 4 . sep . punctuate comma $
                                 map showDependency missing)
                Right pd -> return (pd,[])

            when (not (null flags)) $
              info verbosity $ "Flags chosen: " ++ (concat . intersperse ", " .
                          map (\(n,b) -> n ++ "=" ++ show b) $ flags)

            (warns, ers) <- sanityCheckPackage $
                              updatePackageDescription pbi pkg_descr

            errorOut verbosity warns ers

            let ipkgs = fromMaybe (map setDepByVersion (buildDepends pkg_descr)) mipkgs

            dep_pkgs <- case flavor of
                          GHC | version >= Version [6,3] [] -> do
    	                mapM (configDependency verbosity ipkgs) (buildDepends pkg_descr)
                          JHC                           -> do
    	                mapM (configDependency verbosity ipkgs) (buildDepends pkg_descr)
                          _                             -> do
                            return $ map setDepByVersion (buildDepends pkg_descr)

    	removeInstalledConfig

    	-- installation directories
    	defaultDirs <- defaultInstallDirs flavor (hasLibs pkg_descr)
    	let maybeDefault confField dirField =
    	      maybe (dirField defaultDirs) toPathTemplate (confField cfg)
    	    installDirs = defaultDirs {
    	        prefixDirTemplate  = maybeDefault configPrefix     prefixDirTemplate,
    		binDirTemplate     = maybeDefault configBinDir     binDirTemplate,
    		libDirTemplate     = maybeDefault configLibDir     libDirTemplate,
    		libSubdirTemplate  = maybeDefault configLibSubDir  libSubdirTemplate,
    		libexecDirTemplate = maybeDefault configLibExecDir libexecDirTemplate,
    		dataDirTemplate    = maybeDefault configDataDir    dataDirTemplate,
    		dataSubdirTemplate = maybeDefault configDataSubDir dataSubdirTemplate,
    		docDirTemplate     = maybeDefault configDocDir     docDirTemplate,
    		htmlDirTemplate    = maybeDefault configHtmlDir    htmlDirTemplate,
                    interfaceDirTemplate = maybeDefault configInterfaceDir interfaceDirTemplate
    	      }

            -- check extensions
            let extlist = nub $ concatMap extensions (allBuildInfo pkg_descr)
            let exts = unsupportedExtensions comp extlist
            unless (null exts) $ warn verbosity $ -- Just warn, FIXME: Should this be an error?
                show flavor ++ " does not support the following extensions:\n " ++
                concat (intersperse ", " (map show exts))

            let requiredBuildTools = concatMap buildTools (allBuildInfo pkg_descr)
            programsConfig' <-
                  configureAllKnownPrograms (lessVerbose verbosity) programsConfig
              >>= configureRequiredPrograms verbosity requiredBuildTools

            (pkg_descr', programsConfig'') <- configurePkgconfigPackages verbosity
                                                pkg_descr programsConfig'

    	split_objs <-
    	   if not (configSplitObjs cfg)
    		then return False
    		else case flavor of
    			    GHC | version >= Version [6,5] [] -> return True
    	    		    _ -> do warn verbosity
                                             ("this compiler does not support " ++
    					  "--enable-split-objs; ignoring")
    				    return False

    	let lbi = LocalBuildInfo{
    		    installDirTemplates = installDirs,
    		    compiler            = comp,
    		    buildDir            = distPref </> "build",
    		    scratchDir          = distPref </> "scratch",
    		    packageDeps         = dep_pkgs,
                        pkgDescrFile        = Nothing,
    		    localPkgDescr       = pkg_descr',
    		    withPrograms        = programsConfig'',
    		    withVanillaLib      = configVanillaLib cfg,
    		    withProfLib         = configProfLib cfg,
    		    withSharedLib       = configSharedLib cfg,
    		    withProfExe         = configProfExe cfg,
    		    withOptimization    = configOptimization cfg,
    		    withGHCiLib         = configGHCiLib cfg,
    		    splitObjs           = split_objs,
    		    withPackageDB       = configPackageDB cfg
                      }

            let dirs = absoluteInstallDirs pkg_descr lbi NoCopyDest
                relative = prefixRelativeInstallDirs pkg_descr lbi

            info verbosity $ "Using compiler: " ++ showCompilerId comp
            info verbosity $ "Using install prefix: " ++ prefix dirs

            let dirinfo name dir isPrefixRelative =
                  info verbosity $ name ++ " installed in: " ++ dir ++ relNote
                  where relNote = case os of
                          Windows MingW | not (hasLibs pkg_descr)
                                       && isNothing isPrefixRelative
                                       -> "  (fixed location)"
                          _            -> ""

            dirinfo "Binaries"         (bindir dirs)     (bindir relative)
            dirinfo "Libraries"        (libdir dirs)     (libdir relative)
            dirinfo "Private binaries" (libexecdir dirs) (libexecdir relative)
            dirinfo "Data files"       (datadir dirs)    (datadir relative)
            dirinfo "Documentation"    (docdir dirs)     (docdir relative)

            sequence_ [ reportProgram verbosity prog configuredProg
                      | (prog, configuredProg) <- knownPrograms programsConfig' ]

    	return lbi

    -- -----------------------------------------------------------------------------
    -- Configuring package dependencies

    -- |Converts build dependencies to a versioned dependency.  only sets
    -- version information for exact versioned dependencies.
    setDepByVersion :: Dependency -> PackageIdentifier

    -- if they specify the exact version, use that:
    setDepByVersion (Dependency s (ThisVersion v)) = PackageIdentifier s v

    -- otherwise, just set it to empty
    setDepByVersion (Dependency s _) = PackageIdentifier s (Version [] [])

    reportProgram :: Verbosity -> Program -> Maybe ConfiguredProgram -> IO ()
    reportProgram verbosity prog Nothing
        = info verbosity $ "No " ++ programName prog ++ " found"
    reportProgram verbosity prog (Just configuredProg)
        = info verbosity $ "Using " ++ programName prog ++ version ++ location
        where location = case programLocation configuredProg of
                FoundOnSystem p -> " found on system at: " ++ p
                UserSpecified p -> " given by user at: " ++ p
              version = case programVersion configuredProg of
                Nothing -> ""
                Just v  -> " version " ++ showVersion v

    hackageUrl :: String
    hackageUrl = "http://hackage.haskell.org/cgi-bin/hackage-scripts/package/"

    -- | Test for a package dependency and record the version we have installed.
    configDependency :: Verbosity -> [PackageIdentifier] -> Dependency -> IO PackageIdentifier
    configDependency verbosity ps dep@(Dependency pkgname vrange) =
      case satisfyDependency ps dep of
            Nothing -> die $ "cannot satisfy dependency "
                          ++ pkgname ++ showVersionRange vrange ++ "\n"
                          ++ "Perhaps you need to download and install it from\n"
                          ++ hackageUrl ++ pkgname ++ "?"
            Just pkg -> do info verbosity $ "Dependency " ++ pkgname
                                    ++ showVersionRange vrange
                                    ++ ": using " ++ showPackageId pkg
                           return pkg

    getInstalledPackages :: Verbosity -> Compiler -> PackageDB -> ProgramConfiguration
                         -> IO (Maybe [PackageIdentifier])
    getInstalledPackages verbosity comp packageDb progconf = do
      info verbosity "Reading installed packages..."
      case compilerFlavor comp of
        GHC | compilerVersion comp >= Version [6,3] []
            -> Just `fmap` GHC.getInstalledPackages verbosity packageDb progconf
        JHC -> Just `fmap` JHC.getInstalledPackages verbosity packageDb progconf
        _   -> return Nothing

    -- -----------------------------------------------------------------------------
    -- Configuring program dependencies

    configureRequiredPrograms :: Verbosity -> [Dependency] -> ProgramConfiguration -> IO ProgramConfiguration
    configureRequiredPrograms verbosity deps conf =
      foldM (configureRequiredProgram verbosity) conf deps

    configureRequiredProgram :: Verbosity -> ProgramConfiguration -> Dependency -> IO ProgramConfiguration
    configureRequiredProgram verbosity conf (Dependency progName verRange) =
      case lookupKnownProgram progName conf of
        Nothing -> die ("Unknown build tool " ++ show progName)
        Just prog -> snd `fmap` requireProgram verbosity prog verRange conf

    -- -----------------------------------------------------------------------------
    -- Configuring pkg-config package dependencies

    configurePkgconfigPackages :: Verbosity -> PackageDescription
                               -> ProgramConfiguration
                               -> IO (PackageDescription, ProgramConfiguration)
    configurePkgconfigPackages verbosity pkg_descr conf
      | null allpkgs = return (pkg_descr, conf)
      | otherwise    = do
        (_, conf') <- requireProgram (lessVerbose verbosity) pkgConfigProgram
                        (orLaterVersion $ Version [0,9,0] []) conf
        mapM_ requirePkg allpkgs
        lib'  <- updateLibrary (library pkg_descr)
        exes' <- mapM updateExecutable (executables pkg_descr)
        let pkg_descr' = pkg_descr { library = lib', executables = exes' }
        return (pkg_descr', conf')

      where
        allpkgs = concatMap pkgconfigDepends (allBuildInfo pkg_descr)
        pkgconfig = rawSystemProgramStdoutConf (lessVerbose verbosity)
                      pkgConfigProgram conf

        requirePkg (Dependency pkg range) = do
          version <- pkgconfig ["--modversion", pkg]
                     `Exception.catch` \_ -> die notFound
          case readVersion version of
            Nothing -> die "parsing output of pkg-config --modversion failed"
            Just v | not (withinRange v range) -> die (badVersion v)
                   | otherwise                 -> info verbosity (depSatisfied v)
          where
            notFound     = "The pkg-config package " ++ pkg ++ versionRequirement
                        ++ " is required but it could not be found."
            badVersion v = "The pkg-config package " ++ pkg ++ versionRequirement
                        ++ " is required but the version installed on the"
                        ++ " system is version " ++ showVersion v
            depSatisfied v = "Dependency " ++ pkg ++ showVersionRange range
                          ++ ": using version " ++ showVersion v

            versionRequirement
              | range == AnyVersion = ""
              | otherwise           = " version " ++ showVersionRange range

        updateLibrary Nothing    = return Nothing
        updateLibrary (Just lib) = do
          let bi = libBuildInfo lib
          bi' <- updateBuildInfo bi
          return $ Just lib { libBuildInfo = bi' }

        updateExecutable exe = do
          let bi = buildInfo exe
          bi' <- updateBuildInfo bi
          return exe { buildInfo = bi' }

        updateBuildInfo :: BuildInfo -> IO BuildInfo
        updateBuildInfo bi
          | not (buildable bi) = return bi
          | otherwise = do
          let pkgs = nub [ pkg | Dependency pkg _ <- pkgconfigDepends bi ]
          cflags  <- words `fmap` pkgconfig ("--cflags" : pkgs)
          ldflags <- words `fmap` pkgconfig ("--libs"   : pkgs)
          let (includeDirs',  cflags')   = partition ("-I" `isPrefixOf`) cflags
              (extraLibs',    ldflags')  = partition ("-l" `isPrefixOf`) ldflags
              (extraLibDirs', ldflags'') = partition ("-L" `isPrefixOf`) ldflags'
          return bi {
            includeDirs  = includeDirs  bi ++ map (drop 2) includeDirs',
            extraLibs    = extraLibs    bi ++ map (drop 2) extraLibs',
            extraLibDirs = extraLibDirs bi ++ map (drop 2) extraLibDirs',
            ccOptions    = ccOptions    bi ++ cflags',
            ldOptions    = ldOptions    bi ++ ldflags''
          }

    -- -----------------------------------------------------------------------------
    -- Determining the compiler details

    configCompilerAux :: ConfigFlags -> IO (Compiler, ProgramConfiguration)
    configCompilerAux cfg = configCompiler (configHcFlavor cfg)
                                           (configHcPath cfg)
                                           (configHcPkg cfg)
                                           (configPrograms cfg)
                                           (configVerbose cfg)

    configCompiler :: Maybe CompilerFlavor -> Maybe FilePath -> Maybe FilePath
                   -> ProgramConfiguration -> Verbosity
                   -> IO (Compiler, ProgramConfiguration)
    configCompiler Nothing _ _ _ _ = die "Unknown compiler"
    configCompiler (Just hcFlavor) hcPath hcPkg conf verbosity = do
      case hcFlavor of
          GHC  -> GHC.configure  verbosity hcPath hcPkg conf
          JHC  -> JHC.configure  verbosity hcPath hcPkg conf
          Hugs -> Hugs.configure verbosity hcPath hcPkg conf
          NHC  -> NHC.configure  verbosity hcPath hcPkg conf
          _    -> die "Unknown compiler"

    -- |Output warnings and errors. Exit if any errors.
    errorOut :: Verbosity -- ^Verbosity
             -> [String]  -- ^Warnings
             -> [String]  -- ^errors
             -> IO ()
    errorOut verbosity warnings errors = do
      mapM_ (warn verbosity) warnings
      when (not (null errors)) $ do
        pname <- getProgName
        mapM (hPutStrLn stderr . ((pname ++ ": Error: ") ++)) errors
        exitWith (ExitFailure 1)

    -- -----------------------------------------------------------------------------
    -- Tests

    #ifdef DEBUG

    hunitTests :: [Test]
    hunitTests = []
    {- Too specific:
    packageID = PackageIdentifier "Foo" (Version [1] [])
        = [TestCase $
           do let simonMarGHCLoc = "/usr/bin/ghc"
              simonMarGHC <- configure emptyPackageDescription {package=packageID}
                                           (Just GHC,
    				       Just simonMarGHCLoc,
    				       Nothing, Nothing)
    	  assertEqual "finding ghc, etc on simonMar's machine failed"
                 (LocalBuildInfo "/usr" (Compiler GHC
    	                    (Version [6,2,2] []) simonMarGHCLoc
     			    (simonMarGHCLoc ++ "-pkg")) [] [])
                 simonMarGHC
          ]
    -}
    #endif