{-# LANGUAGE PatternGuards #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  Distribution.Simple.GHC.Internal
-- Copyright   :  Isaac Jones 2003-2007
--
-- Maintainer  :  cabal-devel@haskell.org
-- Portability :  portable
--
-- This module contains functions shared by GHC (Distribution.Simple.GHC)
-- and GHC-derived compilers.

module Distribution.Simple.GHC.Internal (
        configureToolchain,
        getLanguages,
        getExtensions,
        targetPlatform,
        getGhcInfo,
        componentCcGhcOptions,
        componentGhcOptions,
        mkGHCiLibName,
        filterGhciFlags,
        ghcLookupProperty,
        getHaskellObjects,
        mkGhcOptPackages,
        substTopDir,
        checkPackageDbEnvVar,
        profDetailLevelFlag,
        showArchString,
        showOsString,
 ) where

import Distribution.Simple.GHC.ImplInfo
import Distribution.Package
import Distribution.InstalledPackageInfo
import qualified Distribution.InstalledPackageInfo as InstalledPackageInfo
import Distribution.PackageDescription as PD hiding (Flag)
import Distribution.Compat.Exception
import Distribution.Lex
import Distribution.Simple.Compiler hiding (Flag)
import Distribution.Simple.Program.GHC
import Distribution.Simple.Setup
import qualified Distribution.ModuleName as ModuleName
import Distribution.Simple.Program
import Distribution.Simple.LocalBuildInfo
import Distribution.Simple.Utils
import Distribution.Simple.BuildPaths
import Distribution.System
import Distribution.Text ( display, simpleParse )
import Distribution.Utils.NubList ( toNubListR )
import Distribution.Verbosity
import Language.Haskell.Extension

import qualified Data.Map as M
import Data.Char                ( isSpace )
import Data.Maybe               ( fromMaybe, maybeToList, isJust )
import Control.Monad            ( unless, when )
import Data.Monoid as Mon       ( Monoid(..) )
import System.Directory         ( getDirectoryContents, getTemporaryDirectory )
import System.Environment       ( getEnv )
import System.FilePath          ( (</>), (<.>), takeExtension
                                , takeDirectory, takeFileName)
import System.IO                ( hClose, hPutStrLn )

targetPlatform :: [(String, String)] -> Maybe Platform
targetPlatform ghcInfo = platformFromTriple =<< lookup "Target platform" ghcInfo

-- | Adjust the way we find and configure gcc and ld
--
configureToolchain :: GhcImplInfo
                   -> ConfiguredProgram
                   -> M.Map String String
                   -> ProgramConfiguration
                   -> ProgramConfiguration
configureToolchain implInfo ghcProg ghcInfo =
    addKnownProgram gccProgram {
      programFindLocation = findProg gccProgramName extraGccPath,
      programPostConf     = configureGcc
    }
  . addKnownProgram ldProgram {
      programFindLocation = findProg ldProgramName extraLdPath,
      programPostConf     = configureLd
    }
  . addKnownProgram arProgram {
      programFindLocation = findProg arProgramName extraArPath
    }
  . addKnownProgram stripProgram {
      programFindLocation = findProg stripProgramName extraStripPath
    }
  where
    compilerDir = takeDirectory (programPath ghcProg)
    baseDir     = takeDirectory compilerDir
    mingwBinDir = baseDir </> "mingw" </> "bin"
    libDir      = baseDir </> "gcc-lib"
    includeDir  = baseDir </> "include" </> "mingw"
    isWindows   = case buildOS of Windows -> True; _ -> False
    binPrefix   = ""

    maybeName :: Program -> Maybe FilePath -> String
    maybeName prog   = maybe (programName prog) (dropExeExtension . takeFileName)

    gccProgramName   = maybeName gccProgram   mbGccLocation
    ldProgramName    = maybeName ldProgram    mbLdLocation
    arProgramName    = maybeName arProgram    mbArLocation
    stripProgramName = maybeName stripProgram mbStripLocation

    mkExtraPath :: Maybe FilePath -> FilePath -> [FilePath]
    mkExtraPath mbPath mingwPath | isWindows = mbDir ++ [mingwPath]
                                 | otherwise = mbDir
      where
        mbDir = maybeToList . fmap takeDirectory $ mbPath

    extraGccPath   = mkExtraPath mbGccLocation   windowsExtraGccDir
    extraLdPath    = mkExtraPath mbLdLocation    windowsExtraLdDir
    extraArPath    = mkExtraPath mbArLocation    windowsExtraArDir
    extraStripPath = mkExtraPath mbStripLocation windowsExtraStripDir

    -- on Windows finding and configuring ghc's gcc & binutils is a bit special
    (windowsExtraGccDir, windowsExtraLdDir,
     windowsExtraArDir, windowsExtraStripDir)
      | separateGccMingw implInfo = (baseDir, libDir, libDir, libDir)
      | otherwise                 = -- GHC >= 6.12
          let b = mingwBinDir </> binPrefix
          in  (b, b, b, b)

    findProg :: String -> [FilePath]
             -> Verbosity -> ProgramSearchPath
             -> IO (Maybe (FilePath, [FilePath]))
    findProg progName extraPath v searchpath =
        findProgramOnSearchPath v searchpath' progName
      where
        searchpath' = (map ProgramSearchPathDir extraPath) ++ searchpath

    -- Read tool locations from the 'ghc --info' output. Useful when
    -- cross-compiling.
    mbGccLocation   = M.lookup "C compiler command" ghcInfo
    mbLdLocation    = M.lookup "ld command" ghcInfo
    mbArLocation    = M.lookup "ar command" ghcInfo
    mbStripLocation = M.lookup "strip command" ghcInfo

    ccFlags        = getFlags "C compiler flags"
    gccLinkerFlags = getFlags "Gcc Linker flags"
    ldLinkerFlags  = getFlags "Ld Linker flags"

    -- It appears that GHC 7.6 and earlier encode the tokenized flags as a
    -- [String] in these settings whereas later versions just encode the flags as
    -- String.
    --
    -- We first try to parse as a [String] and if this fails then tokenize the
    -- flags ourself.
    getFlags :: String -> [String]
    getFlags key =
        case M.lookup key ghcInfo of
          Nothing -> []
          Just flags
            | (flags', ""):_ <- reads flags -> flags'
            | otherwise -> tokenizeQuotedWords flags

    configureGcc :: Verbosity -> ConfiguredProgram -> IO ConfiguredProgram
    configureGcc v gccProg = do
      gccProg' <- configureGcc' v gccProg
      return gccProg' {
        programDefaultArgs = programDefaultArgs gccProg'
                             ++ ccFlags ++ gccLinkerFlags
      }

    configureGcc' :: Verbosity -> ConfiguredProgram -> IO ConfiguredProgram
    configureGcc'
      | isWindows = \_ gccProg -> case programLocation gccProg of
          -- if it's found on system then it means we're using the result
          -- of programFindLocation above rather than a user-supplied path
          -- Pre GHC 6.12, that meant we should add these flags to tell
          -- ghc's gcc where it lives and thus where gcc can find its
          -- various files:
          FoundOnSystem {}
           | separateGccMingw implInfo ->
               return gccProg { programDefaultArgs = ["-B" ++ libDir,
                                                      "-I" ++ includeDir] }
          _ -> return gccProg
      | otherwise = \_ gccProg -> return gccProg

    configureLd :: Verbosity -> ConfiguredProgram -> IO ConfiguredProgram
    configureLd v ldProg = do
      ldProg' <- configureLd' v ldProg
      return ldProg' {
        programDefaultArgs = programDefaultArgs ldProg' ++ ldLinkerFlags
      }

    -- we need to find out if ld supports the -x flag
    configureLd' :: Verbosity -> ConfiguredProgram -> IO ConfiguredProgram
    configureLd' verbosity ldProg = do
      tempDir <- getTemporaryDirectory
      ldx <- withTempFile tempDir ".c" $ \testcfile testchnd ->
             withTempFile tempDir ".o" $ \testofile testohnd -> do
               hPutStrLn testchnd "int foo() { return 0; }"
               hClose testchnd; hClose testohnd
               rawSystemProgram verbosity ghcProg ["-c", testcfile,
                                                   "-o", testofile]
               withTempFile tempDir ".o" $ \testofile' testohnd' ->
                 do
                   hClose testohnd'
                   _ <- rawSystemProgramStdout verbosity ldProg
                     ["-x", "-r", testofile, "-o", testofile']
                   return True
                 `catchIO`   (\_ -> return False)
                 `catchExit` (\_ -> return False)
      if ldx
        then return ldProg { programDefaultArgs = ["-x"] }
        else return ldProg

getLanguages :: Verbosity -> GhcImplInfo -> ConfiguredProgram
             -> IO [(Language, String)]
getLanguages _ implInfo _
  -- TODO: should be using --supported-languages rather than hard coding
  | supportsHaskell2010 implInfo = return [(Haskell98,   "-XHaskell98")
                                          ,(Haskell2010, "-XHaskell2010")]
  | otherwise                    = return [(Haskell98,   "")]

getGhcInfo :: Verbosity -> GhcImplInfo -> ConfiguredProgram
           -> IO [(String, String)]
getGhcInfo verbosity implInfo ghcProg
  | flagInfoLanguages implInfo = do
      xs <- getProgramOutput verbosity (suppressOverrideArgs ghcProg)
                 ["--info"]
      case reads xs of
        [(i, ss)]
          | all isSpace ss ->
              return i
        _ ->
          die "Can't parse --info output of GHC"
  | otherwise =
      return []

getExtensions :: Verbosity -> GhcImplInfo -> ConfiguredProgram
              -> IO [(Extension, String)]
getExtensions verbosity implInfo ghcProg
  | flagInfoLanguages implInfo = do
    str <- getProgramOutput verbosity (suppressOverrideArgs ghcProg)
              ["--supported-languages"]
    let extStrs = if reportsNoExt implInfo
                  then lines str
                  else -- Older GHCs only gave us either Foo or NoFoo,
                       -- so we have to work out the other one ourselves
                       [ extStr''
                       | extStr <- lines str
                       , let extStr' = case extStr of
                                       'N' : 'o' : xs -> xs
                                       _              -> "No" ++ extStr
                       , extStr'' <- [extStr, extStr']
                       ]
    let extensions0 = [ (ext, "-X" ++ display ext)
                      | Just ext <- map simpleParse extStrs ]
        extensions1 = if fakeRecordPuns implInfo
                      then -- ghc-6.8 introduced RecordPuns however it
                           -- should have been NamedFieldPuns. We now
                           -- encourage packages to use NamedFieldPuns
                           -- so for compatibility we fake support for
                           -- it in ghc-6.8 by making it an alias for
                           -- the old RecordPuns extension.
                           (EnableExtension  NamedFieldPuns, "-XRecordPuns") :
                           (DisableExtension NamedFieldPuns, "-XNoRecordPuns") :
                           extensions0
                      else extensions0
        extensions2 = if alwaysNondecIndent implInfo
                      then -- ghc-7.2 split NondecreasingIndentation off
                           -- into a proper extension. Before that it
                           -- was always on.
                           (EnableExtension  NondecreasingIndentation, "") :
                           (DisableExtension NondecreasingIndentation, "") :
                           extensions1
                      else extensions1
    return extensions2

  | otherwise = return oldLanguageExtensions

-- | For GHC 6.6.x and earlier, the mapping from supported extensions to flags
oldLanguageExtensions :: [(Extension, String)]
oldLanguageExtensions =
    let doFlag (f, (enable, disable)) = [(EnableExtension  f, enable),
                                         (DisableExtension f, disable)]
        fglasgowExts = ("-fglasgow-exts",
                        "") -- This is wrong, but we don't want to turn
                            -- all the extensions off when asked to just
                            -- turn one off
        fFlag flag = ("-f" ++ flag, "-fno-" ++ flag)
    in concatMap doFlag
    [(OverlappingInstances       , fFlag "allow-overlapping-instances")
    ,(TypeSynonymInstances       , fglasgowExts)
    ,(TemplateHaskell            , fFlag "th")
    ,(ForeignFunctionInterface   , fFlag "ffi")
    ,(MonomorphismRestriction    , fFlag "monomorphism-restriction")
    ,(MonoPatBinds               , fFlag "mono-pat-binds")
    ,(UndecidableInstances       , fFlag "allow-undecidable-instances")
    ,(IncoherentInstances        , fFlag "allow-incoherent-instances")
    ,(Arrows                     , fFlag "arrows")
    ,(Generics                   , fFlag "generics")
    ,(ImplicitPrelude            , fFlag "implicit-prelude")
    ,(ImplicitParams             , fFlag "implicit-params")
    ,(CPP                        , ("-cpp", ""{- Wrong -}))
    ,(BangPatterns               , fFlag "bang-patterns")
    ,(KindSignatures             , fglasgowExts)
    ,(RecursiveDo                , fglasgowExts)
    ,(ParallelListComp           , fglasgowExts)
    ,(MultiParamTypeClasses      , fglasgowExts)
    ,(FunctionalDependencies     , fglasgowExts)
    ,(Rank2Types                 , fglasgowExts)
    ,(RankNTypes                 , fglasgowExts)
    ,(PolymorphicComponents      , fglasgowExts)
    ,(ExistentialQuantification  , fglasgowExts)
    ,(ScopedTypeVariables        , fFlag "scoped-type-variables")
    ,(FlexibleContexts           , fglasgowExts)
    ,(FlexibleInstances          , fglasgowExts)
    ,(EmptyDataDecls             , fglasgowExts)
    ,(PatternGuards              , fglasgowExts)
    ,(GeneralizedNewtypeDeriving , fglasgowExts)
    ,(MagicHash                  , fglasgowExts)
    ,(UnicodeSyntax              , fglasgowExts)
    ,(PatternSignatures          , fglasgowExts)
    ,(UnliftedFFITypes           , fglasgowExts)
    ,(LiberalTypeSynonyms        , fglasgowExts)
    ,(TypeOperators              , fglasgowExts)
    ,(GADTs                      , fglasgowExts)
    ,(RelaxedPolyRec             , fglasgowExts)
    ,(ExtendedDefaultRules       , fFlag "extended-default-rules")
    ,(UnboxedTuples              , fglasgowExts)
    ,(DeriveDataTypeable         , fglasgowExts)
    ,(ConstrainedClassMethods    , fglasgowExts)
    ]

componentCcGhcOptions :: Verbosity -> GhcImplInfo -> LocalBuildInfo
                      -> BuildInfo -> ComponentLocalBuildInfo
                      -> FilePath -> FilePath
                      -> GhcOptions
componentCcGhcOptions verbosity implInfo lbi bi clbi pref filename =
    mempty {
      ghcOptVerbosity      = toFlag verbosity,
      ghcOptMode           = toFlag GhcModeCompile,
      ghcOptInputFiles     = toNubListR [filename],

      ghcOptCppIncludePath = toNubListR $ [autogenModulesDir lbi, odir]
                                          ++ PD.includeDirs bi,
      ghcOptPackageDBs     = withPackageDB lbi,
      ghcOptPackages       = toNubListR $ mkGhcOptPackages clbi,
      ghcOptCcOptions      = toNubListR $
                             (case withOptimization lbi of
                                  NoOptimisation -> []
                                  _              -> ["-O2"]) ++
                             (case withDebugInfo lbi of
                                  NoDebugInfo   -> []
                                  MinimalDebugInfo -> ["-g1"]
                                  NormalDebugInfo  -> ["-g"]
                                  MaximalDebugInfo -> ["-g3"]) ++
                                  PD.ccOptions bi,
      ghcOptObjDir         = toFlag odir
    }
  where
    odir | hasCcOdirBug implInfo = pref </> takeDirectory filename
         | otherwise             = pref
         -- ghc 6.4.0 had a bug in -odir handling for C compilations.

componentGhcOptions :: Verbosity -> LocalBuildInfo
                    -> BuildInfo -> ComponentLocalBuildInfo -> FilePath
                    -> GhcOptions
componentGhcOptions verbosity lbi bi clbi odir =
    mempty {
      ghcOptVerbosity       = toFlag verbosity,
      ghcOptHideAllPackages = toFlag True,
      ghcOptCabal           = toFlag True,
      ghcOptThisUnitId      = case clbi of
        LibComponentLocalBuildInfo { componentCompatPackageKey = pk }
          -> toFlag pk
        _ -> Mon.mempty,
      ghcOptPackageDBs      = withPackageDB lbi,
      ghcOptPackages        = toNubListR $ mkGhcOptPackages clbi,
      ghcOptSplitObjs       = toFlag (splitObjs lbi),
      ghcOptSourcePathClear = toFlag True,
      ghcOptSourcePath      = toNubListR $ [odir] ++ (hsSourceDirs bi)
                                           ++ [autogenModulesDir lbi],
      ghcOptCppIncludePath  = toNubListR $ [autogenModulesDir lbi, odir]
                                           ++ PD.includeDirs bi,
      ghcOptCppOptions      = toNubListR $ cppOptions bi,
      ghcOptCppIncludes     = toNubListR $
                              [autogenModulesDir lbi </> cppHeaderName],
      ghcOptFfiIncludes     = toNubListR $ PD.includes bi,
      ghcOptObjDir          = toFlag odir,
      ghcOptHiDir           = toFlag odir,
      ghcOptStubDir         = toFlag odir,
      ghcOptOutputDir       = toFlag odir,
      ghcOptOptimisation    = toGhcOptimisation (withOptimization lbi),
      ghcOptDebugInfo       = toGhcDebugInfo (withDebugInfo lbi),
      ghcOptExtra           = toNubListR $ hcOptions GHC bi,
      ghcOptLanguage        = toFlag (fromMaybe Haskell98 (defaultLanguage bi)),
      -- Unsupported extensions have already been checked by configure
      ghcOptExtensions      = toNubListR $ usedExtensions bi,
      ghcOptExtensionMap    = M.fromList . compilerExtensions $ (compiler lbi)
    }
  where
    toGhcOptimisation NoOptimisation      = mempty --TODO perhaps override?
    toGhcOptimisation NormalOptimisation  = toFlag GhcNormalOptimisation
    toGhcOptimisation MaximumOptimisation = toFlag GhcMaximumOptimisation

    -- GHC doesn't support debug info levels yet.
    toGhcDebugInfo NoDebugInfo      = mempty
    toGhcDebugInfo MinimalDebugInfo = toFlag True
    toGhcDebugInfo NormalDebugInfo  = toFlag True
    toGhcDebugInfo MaximalDebugInfo = toFlag True

-- | Strip out flags that are not supported in ghci
filterGhciFlags :: [String] -> [String]
filterGhciFlags = filter supported
  where
    supported ('-':'O':_) = False
    supported "-debug"    = False
    supported "-threaded" = False
    supported "-ticky"    = False
    supported "-eventlog" = False
    supported "-prof"     = False
    supported "-unreg"    = False
    supported _           = True

mkGHCiLibName :: UnitId -> String
mkGHCiLibName lib = getHSLibraryName lib <.> "o"

ghcLookupProperty :: String -> Compiler -> Bool
ghcLookupProperty prop comp =
  case M.lookup prop (compilerProperties comp) of
    Just "YES" -> True
    _          -> False

-- when using -split-objs, we need to search for object files in the
-- Module_split directory for each module.
getHaskellObjects :: GhcImplInfo -> Library -> LocalBuildInfo
                  -> FilePath -> String -> Bool -> IO [FilePath]
getHaskellObjects implInfo lib lbi pref wanted_obj_ext allow_split_objs
  | splitObjs lbi && allow_split_objs = do
        let splitSuffix = if   noExtInSplitSuffix implInfo
                          then "_split"
                          else "_" ++ wanted_obj_ext ++ "_split"
            dirs = [ pref </> (ModuleName.toFilePath x ++ splitSuffix)
                   | x <- libModules lib ]
        objss <- mapM getDirectoryContents dirs
        let objs = [ dir </> obj
                   | (objs',dir) <- zip objss dirs, obj <- objs',
                     let obj_ext = takeExtension obj,
                     '.':wanted_obj_ext == obj_ext ]
        return objs
  | otherwise  =
        return [ pref </> ModuleName.toFilePath x <.> wanted_obj_ext
               | x <- libModules lib ]

mkGhcOptPackages :: ComponentLocalBuildInfo
                 -> [(UnitId, PackageId, ModuleRenaming)]
mkGhcOptPackages clbi =
  map (\(i,p) -> (i,p,lookupRenaming p (componentPackageRenaming clbi)))
      (componentPackageDeps clbi)

substTopDir :: FilePath -> InstalledPackageInfo -> InstalledPackageInfo
substTopDir topDir ipo
 = ipo {
       InstalledPackageInfo.importDirs
           = map f (InstalledPackageInfo.importDirs ipo),
       InstalledPackageInfo.libraryDirs
           = map f (InstalledPackageInfo.libraryDirs ipo),
       InstalledPackageInfo.includeDirs
           = map f (InstalledPackageInfo.includeDirs ipo),
       InstalledPackageInfo.frameworkDirs
           = map f (InstalledPackageInfo.frameworkDirs ipo),
       InstalledPackageInfo.haddockInterfaces
           = map f (InstalledPackageInfo.haddockInterfaces ipo),
       InstalledPackageInfo.haddockHTMLs
           = map f (InstalledPackageInfo.haddockHTMLs ipo)
   }
    where f ('$':'t':'o':'p':'d':'i':'r':rest) = topDir ++ rest
          f x = x

-- Cabal does not use the environment variable GHC{,JS}_PACKAGE_PATH; let
-- users know that this is the case. See ticket #335. Simply ignoring it is
-- not a good idea, since then ghc and cabal are looking at different sets
-- of package DBs and chaos is likely to ensue.
--
-- An exception to this is when running cabal from within a `cabal exec`
-- environment. In this case, `cabal exec` will set the
-- CABAL_SANDBOX_PACKAGE_PATH to the same value that it set
-- GHC{,JS}_PACKAGE_PATH to. If that is the case it is OK to allow
-- GHC{,JS}_PACKAGE_PATH.
checkPackageDbEnvVar :: String -> String -> IO ()
checkPackageDbEnvVar compilerName packagePathEnvVar = do
    mPP <- lookupEnv packagePathEnvVar
    when (isJust mPP) $ do
        mcsPP <- lookupEnv "CABAL_SANDBOX_PACKAGE_PATH"
        unless (mPP == mcsPP) abort
    where
        lookupEnv :: String -> IO (Maybe String)
        lookupEnv name = (Just `fmap` getEnv name)
                         `catchIO` const (return Nothing)
        abort =
            die $ "Use of " ++ compilerName ++ "'s environment variable "
               ++ packagePathEnvVar ++ " is incompatible with Cabal. Use the "
               ++ "flag --package-db to specify a package database (it can be "
               ++ "used multiple times)."

profDetailLevelFlag :: Bool -> ProfDetailLevel -> Flag GhcProfAuto
profDetailLevelFlag forLib mpl =
    case mpl of
      ProfDetailNone                -> mempty
      ProfDetailDefault | forLib    -> toFlag GhcProfAutoExported
                        | otherwise -> toFlag GhcProfAutoToplevel
      ProfDetailExportedFunctions   -> toFlag GhcProfAutoExported
      ProfDetailToplevelFunctions   -> toFlag GhcProfAutoToplevel
      ProfDetailAllFunctions        -> toFlag GhcProfAutoAll
      ProfDetailOther _             -> mempty

-- | GHC's rendering of it's host or target 'Arch' as used in its platform
-- strings and certain file locations (such as user package db location).
--
showArchString :: Arch -> String
showArchString PPC   = "powerpc"
showArchString PPC64 = "powerpc64"
showArchString other = display other

-- | GHC's rendering of it's host or target 'OS' as used in its platform
-- strings and certain file locations (such as user package db location).
--
showOsString :: OS -> String
showOsString Windows = "mingw32"
showOsString OSX     = "darwin"
showOsString Solaris = "solaris2"
showOsString other   = display other
