    -----------------------------------------------------------------------------
    -- |
    -- Module      :  Distribution.Simple.Register
    -- Copyright   :  Isaac Jones 2003-2004
    -- License     :  BSD3
    --
    -- Maintainer  :  cabal-devel@haskell.org
    -- Portability :  portable
    --
    -- This module deals with registering and unregistering packages. There are a
    -- couple ways it can do this, one is to do it directly. Another is to generate
    -- a script that can be run later to do it. The idea here being that the user
    -- is shielded from the details of what command to use for package registration
    -- for a particular compiler. In practice this aspect was not especially
    -- popular so we also provide a way to simply generate the package registration
    -- file which then must be manually passed to @ghc-pkg@. It is possible to
    -- generate registration information for where the package is to be installed,
    -- or alternatively to register the package in place in the build tree. The
    -- latter is occasionally handy, and will become more important when we try to
    -- build multi-package systems.
    --
    -- This module does not delegate anything to the per-compiler modules but just
    -- mixes it all in in this module, which is rather unsatisfactory. The script
    -- generation and the unregister feature are not well used or tested.

    module Distribution.Simple.Register (
        register,
        unregister,

        initPackageDB,
        doesPackageDBExist,
        createPackageDB,
        deletePackageDB,

        invokeHcPkg,
        registerPackage,
        generateRegistrationInfo,
        inplaceInstalledPackageInfo,
        absoluteInstalledPackageInfo,
        generalInstalledPackageInfo,
      ) where

    import Distribution.Simple.LocalBuildInfo
    import Distribution.Simple.BuildPaths

    import qualified Distribution.Simple.GHC   as GHC
    import qualified Distribution.Simple.GHCJS as GHCJS
    import qualified Distribution.Simple.LHC   as LHC
    import qualified Distribution.Simple.UHC   as UHC
    import qualified Distribution.Simple.HaskellSuite as HaskellSuite

    import Distribution.Simple.Compiler
    import Distribution.Simple.Program
    import Distribution.Simple.Program.Script
    import qualified Distribution.Simple.Program.HcPkg as HcPkg
    import Distribution.Simple.Setup
    import Distribution.PackageDescription
    import Distribution.Package
    import qualified Distribution.InstalledPackageInfo as IPI
    import Distribution.InstalledPackageInfo (InstalledPackageInfo)
    import Distribution.Simple.Utils
    import Distribution.System
    import Distribution.Text
    import Distribution.Verbosity as Verbosity

    import System.FilePath ((</>), (<.>), isAbsolute)
    import System.Directory
             ( getCurrentDirectory, removeDirectoryRecursive, removeFile
             , doesDirectoryExist, doesFileExist )

    import Data.Version
    import Control.Monad (when)
    import Data.Maybe
             ( isJust, fromMaybe, maybeToList )
    import Data.List
             ( partition, nub )
    import qualified Data.ByteString.Lazy.Char8 as BS.Char8

    -- -----------------------------------------------------------------------------
    -- Registration

    register :: PackageDescription -> LocalBuildInfo
             -> RegisterFlags -- ^Install in the user's database?; verbose
             -> IO ()
    register pkg@PackageDescription { library       = Just lib  } lbi regFlags
      = do
        let clbi = getComponentLocalBuildInfo lbi CLibName

        absPackageDBs    <- absolutePackageDBPaths packageDbs
        installedPkgInfo <- generateRegistrationInfo
                               verbosity pkg lib lbi clbi inplace reloc distPref
                               (registrationPackageDB absPackageDBs)

        when (fromFlag (regPrintId regFlags)) $ do
          putStrLn (display (IPI.installedUnitId installedPkgInfo))

         -- Three different modes:
        case () of
         _ | modeGenerateRegFile   -> writeRegistrationFile installedPkgInfo
           | modeGenerateRegScript -> writeRegisterScript   installedPkgInfo
           | otherwise             -> do
               setupMessage verbosity "Registering" (packageId pkg)
               registerPackage verbosity (compiler lbi) (withPrograms lbi) False
                               packageDbs installedPkgInfo

      where
        modeGenerateRegFile = isJust (flagToMaybe (regGenPkgConf regFlags))
        regFile             = fromMaybe (display (packageId pkg) <.> "conf")
                                        (fromFlag (regGenPkgConf regFlags))

        modeGenerateRegScript = fromFlag (regGenScript regFlags)

        inplace   = fromFlag (regInPlace regFlags)
        reloc     = relocatable lbi
        -- FIXME: there's really no guarantee this will work.
        -- registering into a totally different db stack can
        -- fail if dependencies cannot be satisfied.
        packageDbs = nub $ withPackageDB lbi
                        ++ maybeToList (flagToMaybe  (regPackageDB regFlags))
        distPref  = fromFlag (regDistPref regFlags)
        verbosity = fromFlag (regVerbosity regFlags)

        writeRegistrationFile installedPkgInfo = do
          notice verbosity ("Creating package registration file: " ++ regFile)
          writeUTF8File regFile (IPI.showInstalledPackageInfo installedPkgInfo)

        writeRegisterScript installedPkgInfo =
          case compilerFlavor (compiler lbi) of
            JHC -> notice verbosity "Registration scripts not needed for jhc"
            UHC -> notice verbosity "Registration scripts not needed for uhc"
            _   -> withHcPkg
                   "Registration scripts are not implemented for this compiler"
                   (compiler lbi) (withPrograms lbi)
                   (writeHcPkgRegisterScript verbosity installedPkgInfo packageDbs)

    register _ _ regFlags = notice verbosity "No package to register"
      where
        verbosity = fromFlag (regVerbosity regFlags)

    generateRegistrationInfo :: Verbosity
                             -> PackageDescription
                             -> Library
                             -> LocalBuildInfo
                             -> ComponentLocalBuildInfo
                             -> Bool
                             -> Bool
                             -> FilePath
                             -> PackageDB
                             -> IO InstalledPackageInfo
    generateRegistrationInfo verbosity pkg lib lbi clbi inplace reloc distPref packageDb = do
      --TODO: eliminate pwd!
      pwd <- getCurrentDirectory

      --TODO: the method of setting the UnitId is compiler specific
      --      this aspect should be delegated to a per-compiler helper.
      let comp = compiler lbi
      abi_hash <-
        case compilerFlavor comp of
         GHC | compilerVersion comp >= Version [6,11] [] -> do
                fmap AbiHash $ GHC.libAbiHash verbosity pkg lbi lib clbi
         GHCJS -> do
                fmap AbiHash $ GHCJS.libAbiHash verbosity pkg lbi lib clbi
         _ -> return (AbiHash "")

      installedPkgInfo <-
        if inplace
          then return (inplaceInstalledPackageInfo pwd distPref
                         pkg abi_hash lib lbi clbi)
        else if reloc
          then relocRegistrationInfo verbosity
                         pkg lib lbi clbi abi_hash packageDb
          else return (absoluteInstalledPackageInfo
                         pkg abi_hash lib lbi clbi)

      return installedPkgInfo{ IPI.abiHash = abi_hash }

    relocRegistrationInfo :: Verbosity
                          -> PackageDescription
                          -> Library
                          -> LocalBuildInfo
                          -> ComponentLocalBuildInfo
                          -> AbiHash
                          -> PackageDB
                          -> IO InstalledPackageInfo
    relocRegistrationInfo verbosity pkg lib lbi clbi abi_hash packageDb =
      case (compilerFlavor (compiler lbi)) of
        GHC -> do fs <- GHC.pkgRoot verbosity lbi packageDb
                  return (relocatableInstalledPackageInfo
                            pkg abi_hash lib lbi clbi fs)
        _   -> die "Distribution.Simple.Register.relocRegistrationInfo: \
                   \not implemented for this compiler"

    initPackageDB :: Verbosity -> Compiler -> ProgramConfiguration -> FilePath -> IO ()
    initPackageDB verbosity comp progdb dbPath =
        createPackageDB verbosity comp progdb False dbPath

    -- | Create an empty package DB at the specified location.
    createPackageDB :: Verbosity -> Compiler -> ProgramConfiguration -> Bool
                    -> FilePath -> IO ()
    createPackageDB verbosity comp progdb preferCompat dbPath =
        case compilerFlavor comp of
          GHC   -> HcPkg.init (GHC.hcPkgInfo   progdb) verbosity preferCompat dbPath
          GHCJS -> HcPkg.init (GHCJS.hcPkgInfo progdb) verbosity False dbPath
          LHC   -> HcPkg.init (LHC.hcPkgInfo   progdb) verbosity False dbPath
          UHC   -> return ()
          HaskellSuite _ -> HaskellSuite.initPackageDB verbosity progdb dbPath
          _              -> die $ "Distribution.Simple.Register.createPackageDB: "
                               ++ "not implemented for this compiler"

    doesPackageDBExist :: FilePath -> IO Bool
    doesPackageDBExist dbPath = do
        -- currently one impl for all compiler flavours, but could change if needed
        dir_exists <- doesDirectoryExist dbPath
        if dir_exists
            then return True
            else doesFileExist dbPath

    deletePackageDB :: FilePath -> IO ()
    deletePackageDB dbPath = do
        -- currently one impl for all compiler flavours, but could change if needed
        dir_exists <- doesDirectoryExist dbPath
        if dir_exists
            then removeDirectoryRecursive dbPath
            else do file_exists <- doesFileExist dbPath
                    when file_exists $ removeFile dbPath

    -- | Run @hc-pkg@ using a given package DB stack, directly forwarding the
    -- provided command-line arguments to it.
    invokeHcPkg :: Verbosity -> Compiler -> ProgramConfiguration -> PackageDBStack
                    -> [String] -> IO ()
    invokeHcPkg verbosity comp conf dbStack extraArgs =
      withHcPkg "invokeHcPkg" comp conf
        (\hpi -> HcPkg.invoke hpi verbosity dbStack extraArgs)

    withHcPkg :: String -> Compiler -> ProgramConfiguration
              -> (HcPkg.HcPkgInfo -> IO a) -> IO a
    withHcPkg name comp conf f =
      case compilerFlavor comp of
        GHC   -> f (GHC.hcPkgInfo conf)
        GHCJS -> f (GHCJS.hcPkgInfo conf)
        LHC   -> f (LHC.hcPkgInfo conf)
        _     -> die ("Distribution.Simple.Register." ++ name ++ ":\
                      \not implemented for this compiler")

    registerPackage :: Verbosity
                    -> Compiler
                    -> ProgramConfiguration
                    -> Bool
                    -> PackageDBStack
                    -> InstalledPackageInfo
                    -> IO ()
    registerPackage verbosity comp progdb multiInstance packageDbs installedPkgInfo =
      case compilerFlavor comp of
        GHC   -> GHC.registerPackage   verbosity progdb multiInstance packageDbs installedPkgInfo
        GHCJS -> GHCJS.registerPackage verbosity progdb multiInstance packageDbs installedPkgInfo
        _ | multiInstance
              -> die "Registering multiple package instances is not yet supported for this compiler"
        LHC   -> LHC.registerPackage   verbosity      progdb packageDbs installedPkgInfo
        UHC   -> UHC.registerPackage   verbosity comp progdb packageDbs installedPkgInfo
        JHC   -> notice verbosity "Registering for jhc (nothing to do)"
        HaskellSuite {} ->
          HaskellSuite.registerPackage verbosity      progdb packageDbs installedPkgInfo
        _    -> die "Registering is not implemented for this compiler"

    writeHcPkgRegisterScript :: Verbosity
                             -> InstalledPackageInfo
                             -> PackageDBStack
                             -> HcPkg.HcPkgInfo
                             -> IO ()
    writeHcPkgRegisterScript verbosity installedPkgInfo packageDbs hpi = do
      let invocation  = HcPkg.reregisterInvocation hpi Verbosity.normal
                          packageDbs (Right installedPkgInfo)
          regScript   = invocationAsSystemScript buildOS invocation

      notice verbosity ("Creating package registration script: " ++ regScriptFileName)
      writeUTF8File regScriptFileName regScript
      setFileExecutable regScriptFileName

    regScriptFileName :: FilePath
    regScriptFileName = case buildOS of
                            Windows -> "register.bat"
                            _       -> "register.sh"

    -- -----------------------------------------------------------------------------
    -- Making the InstalledPackageInfo

    -- | Construct 'InstalledPackageInfo' for a library in a package, given a set
    -- of installation directories.
    --
    generalInstalledPackageInfo
      :: ([FilePath] -> [FilePath]) -- ^ Translate relative include dir paths to
                                    -- absolute paths.
      -> PackageDescription
      -> AbiHash
      -> Library
      -> LocalBuildInfo
      -> ComponentLocalBuildInfo
      -> InstallDirs FilePath
      -> InstalledPackageInfo
    generalInstalledPackageInfo adjustRelIncDirs pkg abi_hash lib lbi clbi installDirs =
      IPI.InstalledPackageInfo {
        IPI.sourcePackageId    = packageId   pkg,
        IPI.installedUnitId    = componentUnitId clbi,
        IPI.compatPackageKey   = componentCompatPackageKey clbi,
        IPI.license            = license     pkg,
        IPI.copyright          = copyright   pkg,
        IPI.maintainer         = maintainer  pkg,
        IPI.author             = author      pkg,
        IPI.stability          = stability   pkg,
        IPI.homepage           = homepage    pkg,
        IPI.pkgUrl             = pkgUrl      pkg,
        IPI.synopsis           = synopsis    pkg,
        IPI.description        = description pkg,
        IPI.category           = category    pkg,
        IPI.abiHash            = abi_hash,
        IPI.exposed            = libExposed  lib,
        IPI.exposedModules     = componentExposedModules clbi,
        IPI.hiddenModules      = otherModules bi,
        IPI.trusted            = IPI.trusted IPI.emptyInstalledPackageInfo,
        IPI.importDirs         = [ libdir installDirs | hasModules ],
        -- Note. the libsubdir and datasubdir templates have already been expanded
        -- into libdir and datadir.
        IPI.libraryDirs        = libdirs,
        IPI.libraryDynDirs     = dynlibdirs,
        IPI.dataDir            = datadir installDirs,
        IPI.hsLibraries        = if hasLibrary
                                   then [getHSLibraryName (componentUnitId clbi)]
                                   else [],
        IPI.extraLibraries     = extraLibs bi,
        IPI.extraGHCiLibraries = extraGHCiLibs bi,
        IPI.includeDirs        = absinc ++ adjustRelIncDirs relinc,
        IPI.includes           = includes bi,
        IPI.depends            = map fst (componentPackageDeps clbi),
        IPI.ccOptions          = [], -- Note. NOT ccOptions bi!
                                     -- We don't want cc-options to be propagated
                                     -- to C compilations in other packages.
        IPI.ldOptions          = ldOptions bi,
        IPI.frameworks         = frameworks bi,
        IPI.frameworkDirs      = extraFrameworkDirs bi,
        IPI.haddockInterfaces  = [haddockdir installDirs </> haddockName pkg],
        IPI.haddockHTMLs       = [htmldir installDirs],
        IPI.pkgRoot            = Nothing
      }
      where
        bi = libBuildInfo lib
        (absinc, relinc) = partition isAbsolute (includeDirs bi)
        hasModules = not $ null (libModules lib)
        comp = compiler lbi
        hasLibrary = hasModules || not (null (cSources bi))
                                || (not (null (jsSources bi)) &&
                                    compilerFlavor comp == GHCJS)
        (libdirs, dynlibdirs)
          | not hasLibrary
          = (extraLibDirs bi, [])
          -- the dynamic-library-dirs defaults to the library-dirs if not specified,
          -- so this works whether the dynamic-library-dirs field is supported or not

          | libraryDynDirSupported comp
          = (libdir    installDirs : extraLibDirs bi,
             dynlibdir installDirs : extraLibDirs bi)

          | otherwise
          = (libdir installDirs : dynlibdir installDirs : extraLibDirs bi, [])
          -- the compiler doesn't understand the dynamic-library-dirs field so we
          -- add the dyn directory to the "normal" list in the library-dirs field

    -- | Construct 'InstalledPackageInfo' for a library that is in place in the
    -- build tree.
    --
    -- This function knows about the layout of in place packages.
    --
    inplaceInstalledPackageInfo :: FilePath -- ^ top of the build tree
                                -> FilePath -- ^ location of the dist tree
                                -> PackageDescription
                                -> AbiHash
                                -> Library
                                -> LocalBuildInfo
                                -> ComponentLocalBuildInfo
                                -> InstalledPackageInfo
    inplaceInstalledPackageInfo inplaceDir distPref pkg abi_hash lib lbi clbi =
        generalInstalledPackageInfo adjustRelativeIncludeDirs
                                    pkg abi_hash lib lbi clbi installDirs
      where
        adjustRelativeIncludeDirs = map (inplaceDir </>)
        libTargetDir
            | componentUnitId clbi == localUnitId lbi = buildDir lbi
            | otherwise = buildDir lbi </> display (componentUnitId clbi)
        installDirs =
          (absoluteInstallDirs pkg lbi NoCopyDest) {
            libdir     = inplaceDir </> libTargetDir,
            dynlibdir  = inplaceDir </> libTargetDir,
            datadir    = inplaceDir </> dataDir pkg,
            docdir     = inplaceDocdir,
            htmldir    = inplaceHtmldir,
            haddockdir = inplaceHtmldir
          }
        inplaceDocdir  = inplaceDir </> distPref </> "doc"
        inplaceHtmldir = inplaceDocdir </> "html" </> display (packageName pkg)

    -- | Construct 'InstalledPackageInfo' for the final install location of a
    -- library package.
    --
    -- This function knows about the layout of installed packages.
    --
    absoluteInstalledPackageInfo :: PackageDescription
                                 -> AbiHash
                                 -> Library
                                 -> LocalBuildInfo
                                 -> ComponentLocalBuildInfo
                                 -> InstalledPackageInfo
    absoluteInstalledPackageInfo pkg abi_hash lib lbi clbi =
        generalInstalledPackageInfo adjustReativeIncludeDirs
                                    pkg abi_hash lib lbi clbi installDirs
      where
        -- For installed packages we install all include files into one dir,
        -- whereas in the build tree they may live in multiple local dirs.
        adjustReativeIncludeDirs _
          | null (installIncludes bi) = []
          | otherwise                 = [includedir installDirs]
        bi = libBuildInfo lib
        installDirs = absoluteInstallDirs pkg lbi NoCopyDest

    relocatableInstalledPackageInfo :: PackageDescription
                                    -> AbiHash
                                    -> Library
                                    -> LocalBuildInfo
                                    -> ComponentLocalBuildInfo
                                    -> FilePath
                                    -> InstalledPackageInfo
    relocatableInstalledPackageInfo pkg abi_hash lib lbi clbi pkgroot =
        generalInstalledPackageInfo adjustReativeIncludeDirs
                                    pkg abi_hash lib lbi clbi installDirs
      where
        -- For installed packages we install all include files into one dir,
        -- whereas in the build tree they may live in multiple local dirs.
        adjustReativeIncludeDirs _
          | null (installIncludes bi) = []
          | otherwise                 = [includedir installDirs]
        bi = libBuildInfo lib

        installDirs = fmap (("${pkgroot}" </>) . shortRelativePath pkgroot)
                    $ absoluteInstallDirs pkg lbi NoCopyDest

    -- -----------------------------------------------------------------------------
    -- Unregistration

    unregister :: PackageDescription -> LocalBuildInfo -> RegisterFlags -> IO ()
    unregister pkg lbi regFlags = do
      let pkgid     = packageId pkg
          genScript = fromFlag (regGenScript regFlags)
          verbosity = fromFlag (regVerbosity regFlags)
          packageDb = fromFlagOrDefault (registrationPackageDB (withPackageDB lbi))
                                        (regPackageDB regFlags)
          unreg hpi =
            let invocation = HcPkg.unregisterInvocation
                               hpi Verbosity.normal packageDb pkgid
            in if genScript
                 then writeFileAtomic unregScriptFileName
                        (BS.Char8.pack $ invocationAsSystemScript buildOS invocation)
                 else runProgramInvocation verbosity invocation
      setupMessage verbosity "Unregistering" pkgid
      withHcPkg "unregistering is only implemented for GHC and GHCJS"
        (compiler lbi) (withPrograms lbi) unreg

    unregScriptFileName :: FilePath
    unregScriptFileName = case buildOS of
                              Windows -> "unregister.bat"
                              _       -> "unregister.sh"