{-# LANGUAGE CPP #-}
{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE RankNTypes #-}

-----------------------------------------------------------------------------
-- |
-- Module      :  Distribution.Simple.Setup
-- Copyright   :  Isaac Jones 2003-2004
--                Duncan Coutts 2007
-- License     :  BSD3
--
-- Maintainer  :  cabal-devel@haskell.org
-- Portability :  portable
--
-- This is a big module, but not very complicated. The code is very regular
-- and repetitive. It defines the command line interface for all the Cabal
-- commands. For each command (like @configure@, @build@ etc) it defines a type
-- that holds all the flags, the default set of flags and a 'CommandUI' that
-- maps command line flags to and from the corresponding flags type.
--
-- All the flags types are instances of 'Monoid', see
-- <http://www.haskell.org/pipermail/cabal-devel/2007-December/001509.html>
-- for an explanation.
--
-- The types defined here get used in the front end and especially in
-- @cabal-install@ which has to do quite a bit of manipulating sets of command
-- line flags.
--
-- This is actually relatively nice, it works quite well. The main change it
-- needs is to unify it with the code for managing sets of fields that can be
-- read and written from files. This would allow us to save configure flags in
-- config files.

module Distribution.Simple.Setup (

  GlobalFlags(..),   emptyGlobalFlags,   defaultGlobalFlags,   globalCommand,
  ConfigFlags(..),   emptyConfigFlags,   defaultConfigFlags,   configureCommand,
  configPrograms,
  configAbsolutePaths, readPackageDb, readPackageDbList, showPackageDb, showPackageDbList,
  CopyFlags(..),     emptyCopyFlags,     defaultCopyFlags,     copyCommand,
  InstallFlags(..),  emptyInstallFlags,  defaultInstallFlags,  installCommand,
  HaddockTarget(..),
  HaddockFlags(..),  emptyHaddockFlags,  defaultHaddockFlags,  haddockCommand,
  Visibility(..),
  HaddockProjectFlags(..), emptyHaddockProjectFlags, defaultHaddockProjectFlags, haddockProjectCommand,
  HscolourFlags(..), emptyHscolourFlags, defaultHscolourFlags, hscolourCommand,
  BuildFlags(..),    emptyBuildFlags,    defaultBuildFlags,    buildCommand,
  DumpBuildInfo(..),
  ReplFlags(..),                         defaultReplFlags,     replCommand,
  ReplOptions(..),
  CleanFlags(..),    emptyCleanFlags,    defaultCleanFlags,    cleanCommand,
  RegisterFlags(..), emptyRegisterFlags, defaultRegisterFlags, registerCommand,
                                                               unregisterCommand,
  SDistFlags(..),    emptySDistFlags,    defaultSDistFlags,    sdistCommand,
  TestFlags(..),     emptyTestFlags,     defaultTestFlags,     testCommand,
  TestShowDetails(..),
  BenchmarkFlags(..), emptyBenchmarkFlags,
  defaultBenchmarkFlags, benchmarkCommand,
  CopyDest(..),
  configureArgs, configureOptions, configureCCompiler, configureLinker,
  buildOptions, haddockOptions, haddockProjectOptions, installDirsOptions,
  testOptions', benchmarkOptions',
  programDbOptions, programDbPaths',
  programFlagsDescription,
  replOptions,
  splitArgs,

  defaultDistPref, optionDistPref,

  Flag(..),
  toFlag,
  fromFlag,
  fromFlagOrDefault,
  flagToMaybe,
  flagToList,
  maybeToFlag,
  BooleanFlag(..),
  boolOpt, boolOpt', trueArg, falseArg,
  optionVerbosity, optionNumJobs) where

import Prelude ()
import Distribution.Compat.Prelude hiding (get)

import Distribution.Compiler
import Distribution.ReadE
import Distribution.Parsec
import Distribution.Pretty
import qualified Distribution.Compat.CharParsing as P
import qualified Text.PrettyPrint as Disp
import Distribution.ModuleName
import Distribution.PackageDescription
import Distribution.Simple.Command hiding (boolOpt, boolOpt')
import qualified Distribution.Simple.Command as Command
import Distribution.Simple.Compiler
import Distribution.Simple.Flag
import Distribution.Simple.Utils
import Distribution.Simple.Program
import Distribution.Simple.InstallDirs
import Distribution.Verbosity
import Distribution.Utils.NubList
import Distribution.Types.ComponentId
import Distribution.Types.DumpBuildInfo
import Distribution.Types.GivenComponent
import Distribution.Types.Module
import Distribution.Types.PackageVersionConstraint

import Distribution.Compat.Stack
import Distribution.Compat.Semigroup (Last' (..), Option' (..))

-- FIXME Not sure where this should live
defaultDistPref :: FilePath
defaultDistPref = "dist"

-- ------------------------------------------------------------
-- * Global flags
-- ------------------------------------------------------------

-- In fact since individual flags types are monoids and these are just sets of
-- flags then they are also monoids pointwise. This turns out to be really
-- useful. The mempty is the set of empty flags and mappend allows us to
-- override specific flags. For example we can start with default flags and
-- override with the ones we get from a file or the command line, or both.

-- | Flags that apply at the top level, not to any sub-command.
data GlobalFlags = GlobalFlags {
    globalVersion        :: Flag Bool,
    globalNumericVersion :: Flag Bool
  } deriving (Generic, Typeable)

defaultGlobalFlags :: GlobalFlags
defaultGlobalFlags  = GlobalFlags {
    globalVersion        = Flag False,
    globalNumericVersion = Flag False
  }

globalCommand :: [Command action] -> CommandUI GlobalFlags
globalCommand commands = CommandUI
  { commandName         = ""
  , commandSynopsis     = ""
  , commandUsage        = \pname ->
         "This Setup program uses the Haskell Cabal Infrastructure.\n"
      ++ "See http://www.haskell.org/cabal/ for more information.\n"
      ++ "\n"
      ++ "Usage: " ++ pname ++ " [GLOBAL FLAGS] [COMMAND [FLAGS]]\n"
  , commandDescription = Just $ \pname ->
      let
        commands' = commands ++ [commandAddAction helpCommandUI undefined]
        cmdDescs = getNormalCommandDescriptions commands'
        maxlen    = maximum $ [length name | (name, _) <- cmdDescs]
        align str = str ++ replicate (maxlen - length str) ' '
      in
         "Commands:\n"
      ++ unlines [ "  " ++ align name ++ "    " ++ descr
                 | (name, descr) <- cmdDescs ]
      ++ "\n"
      ++ "For more information about a command use\n"
      ++ "  " ++ pname ++ " COMMAND --help\n\n"
      ++ "Typical steps for installing Cabal packages:\n"
      ++ concat [ "  " ++ pname ++ " " ++ x ++ "\n"
                | x <- ["configure", "build", "install"]]
  , commandNotes        = Nothing
  , commandDefaultFlags = defaultGlobalFlags
  , commandOptions      = \_ ->
      [option ['V'] ["version"]
         "Print version information"
         globalVersion (\v flags -> flags { globalVersion = v })
         trueArg
      ,option [] ["numeric-version"]
         "Print just the version number"
         globalNumericVersion (\v flags -> flags { globalNumericVersion = v })
         trueArg
      ]
  }

emptyGlobalFlags :: GlobalFlags
emptyGlobalFlags = mempty

instance Monoid GlobalFlags where
  mempty = gmempty
  mappend = (<>)

instance Semigroup GlobalFlags where
  (<>) = gmappend

-- ------------------------------------------------------------
-- * Config flags
-- ------------------------------------------------------------

-- | Flags to @configure@ command.
--
-- IMPORTANT: every time a new flag is added, 'D.C.Setup.filterConfigureFlags'
-- should be updated.
-- IMPORTANT: every time a new flag is added, it should be added to the Eq instance
data ConfigFlags = ConfigFlags {
    -- This is the same hack as in 'buildArgs' and 'copyArgs'.
    -- TODO: Stop using this eventually when 'UserHooks' gets changed
    configArgs :: [String],

    --FIXME: the configPrograms is only here to pass info through to configure
    -- because the type of configure is constrained by the UserHooks.
    -- when we change UserHooks next we should pass the initial
    -- ProgramDb directly and not via ConfigFlags
    configPrograms_     :: Option' (Last' ProgramDb), -- ^All programs that
                                                      -- @cabal@ may run
    configProgramPaths  :: [(String, FilePath)], -- ^user specified programs paths
    configProgramArgs   :: [(String, [String])], -- ^user specified programs args
    configProgramPathExtra :: NubList FilePath,  -- ^Extend the $PATH
    configHcFlavor      :: Flag CompilerFlavor, -- ^The \"flavor\" of the
                                                -- compiler, e.g. GHC.
    configHcPath        :: Flag FilePath, -- ^given compiler location
    configHcPkg         :: Flag FilePath, -- ^given hc-pkg location
    configVanillaLib    :: Flag Bool,     -- ^Enable vanilla library
    configProfLib       :: Flag Bool,     -- ^Enable profiling in the library
    configSharedLib     :: Flag Bool,     -- ^Build shared library
    configStaticLib     :: Flag Bool,     -- ^Build static library
    configDynExe        :: Flag Bool,     -- ^Enable dynamic linking of the
                                          -- executables.
    configFullyStaticExe :: Flag Bool,     -- ^Enable fully static linking of the
                                          -- executables.
    configProfExe       :: Flag Bool,     -- ^Enable profiling in the
                                          -- executables.
    configProf          :: Flag Bool,     -- ^Enable profiling in the library
                                          -- and executables.
    configProfDetail    :: Flag ProfDetailLevel, -- ^Profiling detail level
                                          --  in the library and executables.
    configProfLibDetail :: Flag ProfDetailLevel, -- ^Profiling  detail level
                                                 -- in the library
    configConfigureArgs :: [String],      -- ^Extra arguments to @configure@
    configOptimization  :: Flag OptimisationLevel,  -- ^Enable optimization.
    configProgPrefix    :: Flag PathTemplate, -- ^Installed executable prefix.
    configProgSuffix    :: Flag PathTemplate, -- ^Installed executable suffix.
    configInstallDirs   :: InstallDirs (Flag PathTemplate), -- ^Installation
                                                            -- paths
    configScratchDir    :: Flag FilePath,
    configExtraLibDirs  :: [FilePath],   -- ^ path to search for extra libraries
    configExtraLibDirsStatic :: [FilePath],   -- ^ path to search for extra
                                              --   libraries when linking
                                              --   fully static executables
    configExtraFrameworkDirs :: [FilePath],   -- ^ path to search for extra
                                              -- frameworks (OS X only)
    configExtraIncludeDirs :: [FilePath],   -- ^ path to search for header files
    configIPID          :: Flag String, -- ^ explicit IPID to be used
    configCID           :: Flag ComponentId, -- ^ explicit CID to be used
    configDeterministic :: Flag Bool, -- ^ be as deterministic as possible
                                      -- (e.g., invariant over GHC, database,
                                      -- etc).  Used by the test suite

    configDistPref :: Flag FilePath, -- ^"dist" prefix
    configCabalFilePath :: Flag FilePath, -- ^ Cabal file to use
    configVerbosity :: Flag Verbosity, -- ^verbosity level
    configUserInstall :: Flag Bool,    -- ^The --user\/--global flag
    configPackageDBs :: [Maybe PackageDB], -- ^Which package DBs to use
    configGHCiLib   :: Flag Bool,      -- ^Enable compiling library for GHCi
    configSplitSections :: Flag Bool,      -- ^Enable -split-sections with GHC
    configSplitObjs :: Flag Bool,      -- ^Enable -split-objs with GHC
    configStripExes :: Flag Bool,      -- ^Enable executable stripping
    configStripLibs :: Flag Bool,      -- ^Enable library stripping
    configConstraints :: [PackageVersionConstraint], -- ^Additional constraints for
                                                     -- dependencies.
    configDependencies :: [GivenComponent],
      -- ^The packages depended on.
    configInstantiateWith :: [(ModuleName, Module)],
      -- ^ The requested Backpack instantiation.  If empty, either this
      -- package does not use Backpack, or we just want to typecheck
      -- the indefinite package.
    configConfigurationsFlags :: FlagAssignment,
    configTests               :: Flag Bool, -- ^Enable test suite compilation
    configBenchmarks          :: Flag Bool, -- ^Enable benchmark compilation
    configCoverage :: Flag Bool, -- ^Enable program coverage
    configLibCoverage :: Flag Bool, -- ^Enable program coverage (deprecated)
    configExactConfiguration  :: Flag Bool,
      -- ^All direct dependencies and flags are provided on the command line by
      -- the user via the '--dependency' and '--flags' options.
    configFlagError :: Flag String,
      -- ^Halt and show an error message indicating an error in flag assignment
    configRelocatable :: Flag Bool, -- ^ Enable relocatable package built
    configDebugInfo :: Flag DebugInfoLevel,  -- ^ Emit debug info.
    configDumpBuildInfo :: Flag DumpBuildInfo,
      -- ^ Should we dump available build information on build?
      -- Dump build information to disk before attempting to build,
      -- tooling can parse these files and use them to compile the
      -- source files themselves.
    configUseResponseFiles :: Flag Bool,
      -- ^ Whether to use response files at all. They're used for such tools
      -- as haddock, or ld.
    configAllowDependingOnPrivateLibs :: Flag Bool
      -- ^ Allow depending on private sublibraries. This is used by external
      -- tools (like cabal-install) so they can add multiple-public-libraries
      -- compatibility to older ghcs by checking visibility externally.
  }
  deriving (Generic, Read, Show, Typeable)

instance Binary ConfigFlags
instance Structured ConfigFlags

-- | More convenient version of 'configPrograms'. Results in an
-- 'error' if internal invariant is violated.
configPrograms :: WithCallStack (ConfigFlags -> ProgramDb)
configPrograms = fromMaybe (error "FIXME: remove configPrograms") . fmap getLast'
               . getOption' . configPrograms_

instance Eq ConfigFlags where
  (==) a b =
    -- configPrograms skipped: not user specified, has no Eq instance
    equal configProgramPaths
    && equal configProgramArgs
    && equal configProgramPathExtra
    && equal configHcFlavor
    && equal configHcPath
    && equal configHcPkg
    && equal configVanillaLib
    && equal configProfLib
    && equal configSharedLib
    && equal configStaticLib
    && equal configDynExe
    && equal configFullyStaticExe
    && equal configProfExe
    && equal configProf
    && equal configProfDetail
    && equal configProfLibDetail
    && equal configConfigureArgs
    && equal configOptimization
    && equal configProgPrefix
    && equal configProgSuffix
    && equal configInstallDirs
    && equal configScratchDir
    && equal configExtraLibDirs
    && equal configExtraLibDirsStatic
    && equal configExtraIncludeDirs
    && equal configIPID
    && equal configDeterministic
    && equal configDistPref
    && equal configVerbosity
    && equal configUserInstall
    && equal configPackageDBs
    && equal configGHCiLib
    && equal configSplitSections
    && equal configSplitObjs
    && equal configStripExes
    && equal configStripLibs
    && equal configConstraints
    && equal configDependencies
    && equal configConfigurationsFlags
    && equal configTests
    && equal configBenchmarks
    && equal configCoverage
    && equal configLibCoverage
    && equal configExactConfiguration
    && equal configFlagError
    && equal configRelocatable
    && equal configDebugInfo
    && equal configDumpBuildInfo
    && equal configUseResponseFiles
    where
      equal f = on (==) f a b

configAbsolutePaths :: ConfigFlags -> IO ConfigFlags
configAbsolutePaths f =
  (\v -> f { configPackageDBs = v })
  `liftM` traverse (maybe (return Nothing) (liftM Just . absolutePackageDBPath))
  (configPackageDBs f)

defaultConfigFlags :: ProgramDb -> ConfigFlags
defaultConfigFlags progDb = emptyConfigFlags {
    configArgs         = [],
    configPrograms_    = Option' (Just (Last' progDb)),
    configHcFlavor     = maybe NoFlag Flag defaultCompilerFlavor,
    configVanillaLib   = Flag True,
    configProfLib      = NoFlag,
    configSharedLib    = NoFlag,
    configStaticLib    = NoFlag,
    configDynExe       = Flag False,
    configFullyStaticExe = Flag False,
    configProfExe      = NoFlag,
    configProf         = NoFlag,
    configProfDetail   = NoFlag,
    configProfLibDetail= NoFlag,
    configOptimization = Flag NormalOptimisation,
    configProgPrefix   = Flag (toPathTemplate ""),
    configProgSuffix   = Flag (toPathTemplate ""),
    configDistPref     = NoFlag,
    configCabalFilePath = NoFlag,
    configVerbosity    = Flag normal,
    configUserInstall  = Flag False,           --TODO: reverse this
#if defined(mingw32_HOST_OS)
    -- See #8062 and GHC #21019.
    configGHCiLib      = Flag False,
#else
    configGHCiLib      = NoFlag,
#endif
    configSplitSections = Flag False,
    configSplitObjs    = Flag False, -- takes longer, so turn off by default
    configStripExes    = NoFlag,
    configStripLibs    = NoFlag,
    configTests        = Flag False,
    configBenchmarks   = Flag False,
    configCoverage     = Flag False,
    configLibCoverage  = NoFlag,
    configExactConfiguration = Flag False,
    configFlagError    = NoFlag,
    configRelocatable  = Flag False,
    configDebugInfo    = Flag NoDebugInfo,
    configDumpBuildInfo = NoFlag,
    configUseResponseFiles = NoFlag
  }

configureCommand :: ProgramDb -> CommandUI ConfigFlags
configureCommand progDb = CommandUI
  { commandName         = "configure"
  , commandSynopsis     = "Prepare to build the package."
  , commandDescription  = Just $ \_ -> wrapText $
         "Configure how the package is built by setting "
      ++ "package (and other) flags.\n"
      ++ "\n"
      ++ "The configuration affects several other commands, "
      ++ "including build, test, bench, run, repl.\n"
  , commandNotes        = Just $ \_pname -> programFlagsDescription progDb
  , commandUsage        = \pname ->
      "Usage: " ++ pname ++ " configure [FLAGS]\n"
  , commandDefaultFlags = defaultConfigFlags progDb
  , commandOptions      = \showOrParseArgs ->
         configureOptions showOrParseArgs
      ++ programDbPaths   progDb showOrParseArgs
           configProgramPaths (\v fs -> fs { configProgramPaths = v })
      ++ programDbOption progDb showOrParseArgs
           configProgramArgs (\v fs -> fs { configProgramArgs = v })
      ++ programDbOptions progDb showOrParseArgs
           configProgramArgs (\v fs -> fs { configProgramArgs = v })
  }

-- | Inverse to 'dispModSubstEntry'.
parsecModSubstEntry :: ParsecParser (ModuleName, Module)
parsecModSubstEntry = do
    k <- parsec
    _ <- P.char '='
    v <- parsec
    return (k, v)

-- | Pretty-print a single entry of a module substitution.
dispModSubstEntry :: (ModuleName, Module) -> Disp.Doc
dispModSubstEntry (k, v) = pretty k <<>> Disp.char '=' <<>> pretty v

configureOptions :: ShowOrParseArgs -> [OptionField ConfigFlags]
configureOptions showOrParseArgs =
      [optionVerbosity configVerbosity
       (\v flags -> flags { configVerbosity = v })
      ,optionDistPref
         configDistPref (\d flags -> flags { configDistPref = d })
         showOrParseArgs

      ,option [] ["compiler"] "compiler"
         configHcFlavor (\v flags -> flags { configHcFlavor = v })
         (choiceOpt [ (Flag GHC,   ("g", ["ghc"]),   "compile with GHC")
                    , (Flag GHCJS, ([] , ["ghcjs"]), "compile with GHCJS")
                    , (Flag UHC,   ([] , ["uhc"]),   "compile with UHC")
                    -- "haskell-suite" compiler id string will be replaced
                    -- by a more specific one during the configure stage
                    , (Flag (HaskellSuite "haskell-suite"), ([] , ["haskell-suite"]),
                        "compile with a haskell-suite compiler")])

      ,option "" ["cabal-file"]
         "use this Cabal file"
         configCabalFilePath (\v flags -> flags { configCabalFilePath = v })
         (reqArgFlag "PATH")

      ,option "w" ["with-compiler"]
         "give the path to a particular compiler"
         configHcPath (\v flags -> flags { configHcPath = v })
         (reqArgFlag "PATH")

      ,option "" ["with-hc-pkg"]
         "give the path to the package tool"
         configHcPkg (\v flags -> flags { configHcPkg = v })
         (reqArgFlag "PATH")
      ]
   ++ map liftInstallDirs installDirsOptions
   ++ [option "" ["program-prefix"]
          "prefix to be applied to installed executables"
          configProgPrefix
          (\v flags -> flags { configProgPrefix = v })
          (reqPathTemplateArgFlag "PREFIX")

      ,option "" ["program-suffix"]
          "suffix to be applied to installed executables"
          configProgSuffix (\v flags -> flags { configProgSuffix = v } )
          (reqPathTemplateArgFlag "SUFFIX")

      ,option "" ["library-vanilla"]
         "Vanilla libraries"
         configVanillaLib (\v flags -> flags { configVanillaLib = v })
         (boolOpt [] [])

      ,option "p" ["library-profiling"]
         "Library profiling"
         configProfLib (\v flags -> flags { configProfLib = v })
         (boolOpt "p" [])

      ,option "" ["shared"]
         "Shared library"
         configSharedLib (\v flags -> flags { configSharedLib = v })
         (boolOpt [] [])

      ,option "" ["static"]
         "Static library"
         configStaticLib (\v flags -> flags { configStaticLib = v })
         (boolOpt [] [])

      ,option "" ["executable-dynamic"]
         "Executable dynamic linking"
         configDynExe (\v flags -> flags { configDynExe = v })
         (boolOpt [] [])

      ,option "" ["executable-static"]
         "Executable fully static linking"
         configFullyStaticExe (\v flags -> flags { configFullyStaticExe = v })
         (boolOpt [] [])

      ,option "" ["profiling"]
         "Executable and library profiling"
         configProf (\v flags -> flags { configProf = v })
         (boolOpt [] [])

      ,option "" ["executable-profiling"]
         "Executable profiling (DEPRECATED)"
         configProfExe (\v flags -> flags { configProfExe = v })
         (boolOpt [] [])

      ,option "" ["profiling-detail"]
         ("Profiling detail level for executable and library (default, " ++
          "none, exported-functions, toplevel-functions,  all-functions, late).")
         configProfDetail (\v flags -> flags { configProfDetail = v })
         (reqArg' "level" (Flag . flagToProfDetailLevel)
                          showProfDetailLevelFlag)

      ,option "" ["library-profiling-detail"]
         "Profiling detail level for libraries only."
         configProfLibDetail (\v flags -> flags { configProfLibDetail = v })
         (reqArg' "level" (Flag . flagToProfDetailLevel)
                          showProfDetailLevelFlag)

      ,multiOption "optimization"
         configOptimization (\v flags -> flags { configOptimization = v })
         [optArg' "n" (Flag . flagToOptimisationLevel)
                     (\f -> case f of
                              Flag NoOptimisation      -> []
                              Flag NormalOptimisation  -> [Nothing]
                              Flag MaximumOptimisation -> [Just "2"]
                              _                        -> [])
                 "O" ["enable-optimization","enable-optimisation"]
                 "Build with optimization (n is 0--2, default is 1)",
          noArg (Flag NoOptimisation) []
                ["disable-optimization","disable-optimisation"]
                "Build without optimization"
         ]

      ,multiOption "debug-info"
         configDebugInfo (\v flags -> flags { configDebugInfo = v })
         [optArg' "n" (Flag . flagToDebugInfoLevel)
                     (\f -> case f of
                              Flag NoDebugInfo      -> []
                              Flag MinimalDebugInfo -> [Just "1"]
                              Flag NormalDebugInfo  -> [Nothing]
                              Flag MaximalDebugInfo -> [Just "3"]
                              _                     -> [])
                 "" ["enable-debug-info"]
                 "Emit debug info (n is 0--3, default is 0)",
          noArg (Flag NoDebugInfo) []
                ["disable-debug-info"]
                "Don't emit debug info"
         ]

      , multiOption "build-info"
         configDumpBuildInfo
         (\v flags -> flags { configDumpBuildInfo = v })
         [noArg (Flag DumpBuildInfo) []
                ["enable-build-info"]
                "Enable build information generation during project building",
          noArg (Flag NoDumpBuildInfo) []
                ["disable-build-info"]
                "Disable build information generation during project building"
         ]

      ,option "" ["library-for-ghci"]
         "compile library for use with GHCi"
         configGHCiLib (\v flags -> flags { configGHCiLib = v })
         (boolOpt [] [])

      ,option "" ["split-sections"]
         "compile library code such that unneeded definitions can be dropped from the final executable (GHC 7.8+)"
         configSplitSections (\v flags -> flags { configSplitSections = v })
         (boolOpt [] [])

      ,option "" ["split-objs"]
         "split library into smaller objects to reduce binary sizes (GHC 6.6+)"
         configSplitObjs (\v flags -> flags { configSplitObjs = v })
         (boolOpt [] [])

      ,option "" ["executable-stripping"]
         "strip executables upon installation to reduce binary sizes"
         configStripExes (\v flags -> flags { configStripExes = v })
         (boolOpt [] [])

      ,option "" ["library-stripping"]
         "strip libraries upon installation to reduce binary sizes"
         configStripLibs (\v flags -> flags { configStripLibs = v })
         (boolOpt [] [])

      ,option "" ["configure-option"]
         "Extra option for configure"
         configConfigureArgs (\v flags -> flags { configConfigureArgs = v })
         (reqArg' "OPT" (\x -> [x]) id)

      ,option "" ["user-install"]
         "doing a per-user installation"
         configUserInstall (\v flags -> flags { configUserInstall = v })
         (boolOpt' ([],["user"]) ([], ["global"]))

      ,option "" ["package-db"]
         (   "Append the given package database to the list of package"
          ++ " databases used (to satisfy dependencies and register into)."
          ++ " May be a specific file, 'global' or 'user'. The initial list"
          ++ " is ['global'], ['global', 'user'], or ['global', $sandbox],"
          ++ " depending on context. Use 'clear' to reset the list to empty."
          ++ " See the user guide for details.")
         configPackageDBs (\v flags -> flags { configPackageDBs = v })
         (reqArg' "DB" readPackageDbList showPackageDbList)

      ,option "f" ["flags"]
         "Force values for the given flags in Cabal conditionals in the .cabal file.  E.g., --flags=\"debug -usebytestrings\" forces the flag \"debug\" to true and \"usebytestrings\" to false."
         configConfigurationsFlags (\v flags -> flags { configConfigurationsFlags = v })
         (reqArg "FLAGS"
              (parsecToReadE (\err -> "Invalid flag assignment: " ++ err) legacyParsecFlagAssignment)
              legacyShowFlagAssignment')

      ,option "" ["extra-include-dirs"]
         "A list of directories to search for header files"
         configExtraIncludeDirs (\v flags -> flags {configExtraIncludeDirs = v})
         (reqArg' "PATH" (\x -> [x]) id)

      ,option "" ["deterministic"]
         "Try to be as deterministic as possible (used by the test suite)"
         configDeterministic (\v flags -> flags {configDeterministic = v})
         (boolOpt [] [])

      ,option "" ["ipid"]
         "Installed package ID to compile this package as"
         configIPID (\v flags -> flags {configIPID = v})
         (reqArgFlag "IPID")

      ,option "" ["cid"]
         "Installed component ID to compile this component as"
         (fmap prettyShow . configCID) (\v flags -> flags {configCID = fmap mkComponentId v})
         (reqArgFlag "CID")

      ,option "" ["extra-lib-dirs"]
         "A list of directories to search for external libraries"
         configExtraLibDirs (\v flags -> flags {configExtraLibDirs = v})
         (reqArg' "PATH" (\x -> [x]) id)

      ,option "" ["extra-lib-dirs-static"]
         "A list of directories to search for external libraries when linking fully static executables"
         configExtraLibDirsStatic (\v flags -> flags {configExtraLibDirsStatic = v})
         (reqArg' "PATH" (\x -> [x]) id)

      ,option "" ["extra-framework-dirs"]
         "A list of directories to search for external frameworks (OS X only)"
         configExtraFrameworkDirs
         (\v flags -> flags {configExtraFrameworkDirs = v})
         (reqArg' "PATH" (\x -> [x]) id)

      ,option "" ["extra-prog-path"]
         "A list of directories to search for required programs (in addition to the normal search locations)"
         configProgramPathExtra (\v flags -> flags {configProgramPathExtra = v})
         (reqArg' "PATH" (\x -> toNubList [x]) fromNubList)

      ,option "" ["constraint"]
         "A list of additional constraints on the dependencies."
         configConstraints (\v flags -> flags { configConstraints = v})
         (reqArg "DEPENDENCY"
                 (parsecToReadE (const "dependency expected") ((\x -> [x]) `fmap` parsec))
                 (map prettyShow))

      ,option "" ["dependency"]
         "A list of exact dependencies. E.g., --dependency=\"void=void-0.5.8-177d5cdf20962d0581fe2e4932a6c309\""
         configDependencies (\v flags -> flags { configDependencies = v})
         (reqArg "NAME[:COMPONENT_NAME]=CID"
                 (parsecToReadE (const "dependency expected") ((\x -> [x]) `fmap` parsecGivenComponent))
                 (map (\(GivenComponent pn cn cid) ->
                     prettyShow pn
                     ++ case cn of LMainLibName -> ""
                                   LSubLibName n -> ":" ++ prettyShow n
                     ++ "=" ++ prettyShow cid)))

      ,option "" ["instantiate-with"]
        "A mapping of signature names to concrete module instantiations."
        configInstantiateWith (\v flags -> flags { configInstantiateWith = v  })
        (reqArg "NAME=MOD"
            (parsecToReadE ("Cannot parse module substitution: " ++) (fmap (:[]) parsecModSubstEntry))
            (map (Disp.renderStyle defaultStyle . dispModSubstEntry)))

      ,option "" ["tests"]
         "dependency checking and compilation for test suites listed in the package description file."
         configTests (\v flags -> flags { configTests = v })
         (boolOpt [] [])

      ,option "" ["coverage"]
         "build package with Haskell Program Coverage. (GHC only)"
         configCoverage (\v flags -> flags { configCoverage = v })
         (boolOpt [] [])

      ,option "" ["library-coverage"]
         "build package with Haskell Program Coverage. (GHC only) (DEPRECATED)"
         configLibCoverage (\v flags -> flags { configLibCoverage = v })
         (boolOpt [] [])

      ,option "" ["exact-configuration"]
         "All direct dependencies and flags are provided on the command line."
         configExactConfiguration
         (\v flags -> flags { configExactConfiguration = v })
         trueArg

      ,option "" ["benchmarks"]
         "dependency checking and compilation for benchmarks listed in the package description file."
         configBenchmarks (\v flags -> flags { configBenchmarks = v })
         (boolOpt [] [])

      ,option "" ["relocatable"]
         "building a package that is relocatable. (GHC only)"
         configRelocatable (\v flags -> flags { configRelocatable = v})
         (boolOpt [] [])

      ,option "" ["response-files"]
         "enable workaround for old versions of programs like \"ar\" that do not support @file arguments"
         configUseResponseFiles
         (\v flags -> flags { configUseResponseFiles = v })
         (boolOpt' ([], ["disable-response-files"]) ([], []))

      ,option "" ["allow-depending-on-private-libs"]
         (  "Allow depending on private libraries. "
         ++ "If set, the library visibility check MUST be done externally." )
         configAllowDependingOnPrivateLibs
         (\v flags -> flags { configAllowDependingOnPrivateLibs = v })
         trueArg
      ]
  where
    liftInstallDirs =
      liftOption configInstallDirs (\v flags -> flags { configInstallDirs = v })

    reqPathTemplateArgFlag title _sf _lf d get set =
      reqArgFlag title _sf _lf d
        (fmap fromPathTemplate . get) (set . fmap toPathTemplate)

readPackageDbList :: String -> [Maybe PackageDB]
readPackageDbList str = [readPackageDb str]

-- | Parse a PackageDB stack entry
--
-- @since 3.7.0.0
readPackageDb :: String -> Maybe PackageDB
readPackageDb "clear"  = Nothing
readPackageDb "global" = Just GlobalPackageDB
readPackageDb "user"   = Just UserPackageDB
readPackageDb other    = Just (SpecificPackageDB other)

showPackageDbList :: [Maybe PackageDB] -> [String]
showPackageDbList = map showPackageDb

-- | Show a PackageDB stack entry
--
-- @since 3.7.0.0
showPackageDb :: Maybe PackageDB -> String
showPackageDb Nothing                       = "clear"
showPackageDb (Just GlobalPackageDB)        = "global"
showPackageDb (Just UserPackageDB)          = "user"
showPackageDb (Just (SpecificPackageDB db)) = db

showProfDetailLevelFlag :: Flag ProfDetailLevel -> [String]
showProfDetailLevelFlag NoFlag    = []
showProfDetailLevelFlag (Flag dl) = [showProfDetailLevel dl]

parsecGivenComponent :: ParsecParser GivenComponent
parsecGivenComponent = do
  pn <- parsec
  ln <- P.option LMainLibName $ do
    _ <- P.char ':'
    ucn <- parsec
    return $ if unUnqualComponentName ucn == unPackageName pn
             then LMainLibName
             else LSubLibName ucn
  _ <- P.char '='
  cid <- parsec
  return $ GivenComponent pn ln cid

installDirsOptions :: [OptionField (InstallDirs (Flag PathTemplate))]
installDirsOptions =
  [ option "" ["prefix"]
      "bake this prefix in preparation of installation"
      prefix (\v flags -> flags { prefix = v })
      installDirArg

  , option "" ["bindir"]
      "installation directory for executables"
      bindir (\v flags -> flags { bindir = v })
      installDirArg

  , option "" ["libdir"]
      "installation directory for libraries"
      libdir (\v flags -> flags { libdir = v })
      installDirArg

  , option "" ["libsubdir"]
      "subdirectory of libdir in which libs are installed"
      libsubdir (\v flags -> flags { libsubdir = v })
      installDirArg

  , option "" ["dynlibdir"]
      "installation directory for dynamic libraries"
      dynlibdir (\v flags -> flags { dynlibdir = v })
      installDirArg

  , option "" ["libexecdir"]
      "installation directory for program executables"
      libexecdir (\v flags -> flags { libexecdir = v })
      installDirArg

  , option "" ["libexecsubdir"]
      "subdirectory of libexecdir in which private executables are installed"
      libexecsubdir (\v flags -> flags { libexecsubdir = v })
      installDirArg

  , option "" ["datadir"]
      "installation directory for read-only data"
      datadir (\v flags -> flags { datadir = v })
      installDirArg

  , option "" ["datasubdir"]
      "subdirectory of datadir in which data files are installed"
      datasubdir (\v flags -> flags { datasubdir = v })
      installDirArg

  , option "" ["docdir"]
      "installation directory for documentation"
      docdir (\v flags -> flags { docdir = v })
      installDirArg

  , option "" ["htmldir"]
      "installation directory for HTML documentation"
      htmldir (\v flags -> flags { htmldir = v })
      installDirArg

  , option "" ["haddockdir"]
      "installation directory for haddock interfaces"
      haddockdir (\v flags -> flags { haddockdir = v })
      installDirArg

  , option "" ["sysconfdir"]
      "installation directory for configuration files"
      sysconfdir (\v flags -> flags { sysconfdir = v })
      installDirArg
  ]
  where
    installDirArg _sf _lf d get set =
      reqArgFlag "DIR" _sf _lf d
        (fmap fromPathTemplate . get) (set . fmap toPathTemplate)

emptyConfigFlags :: ConfigFlags
emptyConfigFlags = mempty

instance Monoid ConfigFlags where
  mempty = gmempty
  mappend = (<>)

instance Semigroup ConfigFlags where
  (<>) = gmappend

-- ------------------------------------------------------------
-- * Copy flags
-- ------------------------------------------------------------

-- | Flags to @copy@: (destdir, copy-prefix (backwards compat), verbosity)
data CopyFlags = CopyFlags {
    copyDest      :: Flag CopyDest,
    copyDistPref  :: Flag FilePath,
    copyVerbosity :: Flag Verbosity,
    -- This is the same hack as in 'buildArgs'.  But I (ezyang) don't
    -- think it's a hack, it's the right way to make hooks more robust
    -- TODO: Stop using this eventually when 'UserHooks' gets changed
    copyArgs :: [String],
    copyCabalFilePath :: Flag FilePath
  }
  deriving (Show, Generic)

defaultCopyFlags :: CopyFlags
defaultCopyFlags  = CopyFlags {
    copyDest      = Flag NoCopyDest,
    copyDistPref  = NoFlag,
    copyVerbosity = Flag normal,
    copyArgs      = [],
    copyCabalFilePath = mempty
  }

copyCommand :: CommandUI CopyFlags
copyCommand = CommandUI
  { commandName         = "copy"
  , commandSynopsis     = "Copy the files of all/specific components to install locations."
  , commandDescription  = Just $ \_ -> wrapText $
          "Components encompass executables and libraries. "
       ++ "Does not call register, and allows a prefix at install time. "
       ++ "Without the --destdir flag, configure determines location.\n"
  , commandNotes        = Just $ \pname ->
       "Examples:\n"
        ++ "  " ++ pname ++ " copy           "
        ++ "    All the components in the package\n"
        ++ "  " ++ pname ++ " copy foo       "
        ++ "    A component (i.e. lib, exe, test suite)"
  , commandUsage        = usageAlternatives "copy" $
      [ "[FLAGS]"
      , "COMPONENTS [FLAGS]"
      ]
  , commandDefaultFlags = defaultCopyFlags
  , commandOptions      = \showOrParseArgs -> case showOrParseArgs of
      ShowArgs -> filter ((`notElem` ["target-package-db"])
                          . optionName) $ copyOptions ShowArgs
      ParseArgs -> copyOptions ParseArgs
}

copyOptions ::  ShowOrParseArgs -> [OptionField CopyFlags]
copyOptions showOrParseArgs =
  [optionVerbosity copyVerbosity (\v flags -> flags { copyVerbosity = v })

  ,optionDistPref
    copyDistPref (\d flags -> flags { copyDistPref = d })
    showOrParseArgs

  ,option "" ["destdir"]
    "directory to copy files to, prepended to installation directories"
    copyDest (\v flags -> case copyDest flags of
                 Flag (CopyToDb _) -> error "Use either 'destdir' or 'target-package-db'."
                 _ -> flags { copyDest = v })
    (reqArg "DIR" (succeedReadE (Flag . CopyTo))
      (\f -> case f of Flag (CopyTo p) -> [p]; _ -> []))

  ,option "" ["target-package-db"]
    "package database to copy files into. Required when using ${pkgroot} prefix."
    copyDest (\v flags -> case copyDest flags of
                 NoFlag -> flags { copyDest = v }
                 Flag NoCopyDest -> flags { copyDest = v }
                 _ -> error "Use either 'destdir' or 'target-package-db'.")
    (reqArg "DATABASE" (succeedReadE (Flag . CopyToDb))
      (\f -> case f of Flag (CopyToDb p) -> [p]; _ -> []))
  ]

emptyCopyFlags :: CopyFlags
emptyCopyFlags = mempty

instance Monoid CopyFlags where
  mempty = gmempty
  mappend = (<>)

instance Semigroup CopyFlags where
  (<>) = gmappend

-- ------------------------------------------------------------
-- * Install flags
-- ------------------------------------------------------------

-- | Flags to @install@: (package db, verbosity)
data InstallFlags = InstallFlags {
    installPackageDB :: Flag PackageDB,
    installDest      :: Flag CopyDest,
    installDistPref  :: Flag FilePath,
    installUseWrapper :: Flag Bool,
    installInPlace    :: Flag Bool,
    installVerbosity :: Flag Verbosity,
    -- this is only here, because we can not
    -- change the hooks API.
    installCabalFilePath :: Flag FilePath
  }
  deriving (Show, Generic)

defaultInstallFlags :: InstallFlags
defaultInstallFlags  = InstallFlags {
    installPackageDB = NoFlag,
    installDest      = Flag NoCopyDest,
    installDistPref  = NoFlag,
    installUseWrapper = Flag False,
    installInPlace    = Flag False,
    installVerbosity = Flag normal,
    installCabalFilePath = mempty
  }

installCommand :: CommandUI InstallFlags
installCommand = CommandUI
  { commandName         = "install"
  , commandSynopsis     =
      "Copy the files into the install locations. Run register."
  , commandDescription  = Just $ \_ -> wrapText $
         "Unlike the copy command, install calls the register command."
      ++ "If you want to install into a location that is not what was"
      ++ "specified in the configure step, use the copy command.\n"
  , commandNotes        = Nothing
  , commandUsage        = \pname ->
      "Usage: " ++ pname ++ " install [FLAGS]\n"
  , commandDefaultFlags = defaultInstallFlags
  , commandOptions      = \showOrParseArgs -> case showOrParseArgs of
      ShowArgs -> filter ((`notElem` ["target-package-db"])
                          . optionName) $ installOptions ShowArgs
      ParseArgs -> installOptions ParseArgs
  }

installOptions ::  ShowOrParseArgs -> [OptionField InstallFlags]
installOptions showOrParseArgs =
  [optionVerbosity installVerbosity (\v flags -> flags { installVerbosity = v })
  ,optionDistPref
    installDistPref (\d flags -> flags { installDistPref = d })
    showOrParseArgs

  ,option "" ["inplace"]
    "install the package in the install subdirectory of the dist prefix, so it can be used without being installed"
    installInPlace (\v flags -> flags { installInPlace = v })
    trueArg

  ,option "" ["shell-wrappers"]
    "using shell script wrappers around executables"
    installUseWrapper (\v flags -> flags { installUseWrapper = v })
    (boolOpt [] [])

  ,option "" ["package-db"] ""
    installPackageDB (\v flags -> flags { installPackageDB = v })
    (choiceOpt [ (Flag UserPackageDB, ([],["user"]),
                   "upon configuration register this package in the user's local package database")
               , (Flag GlobalPackageDB, ([],["global"]),
                   "(default) upon configuration register this package in the system-wide package database")])
  ,option "" ["target-package-db"]
    "package database to install into. Required when using ${pkgroot} prefix."
    installDest (\v flags -> flags { installDest = v })
    (reqArg "DATABASE" (succeedReadE (Flag . CopyToDb))
      (\f -> case f of Flag (CopyToDb p) -> [p]; _ -> []))
  ]

emptyInstallFlags :: InstallFlags
emptyInstallFlags = mempty

instance Monoid InstallFlags where
  mempty = gmempty
  mappend = (<>)

instance Semigroup InstallFlags where
  (<>) = gmappend

-- ------------------------------------------------------------
-- * SDist flags
-- ------------------------------------------------------------

-- | Flags to @sdist@: (snapshot, verbosity)
data SDistFlags = SDistFlags {
    sDistSnapshot    :: Flag Bool,
    sDistDirectory   :: Flag FilePath,
    sDistDistPref    :: Flag FilePath,
    sDistListSources :: Flag FilePath,
    sDistVerbosity   :: Flag Verbosity
  }
  deriving (Show, Generic, Typeable)

defaultSDistFlags :: SDistFlags
defaultSDistFlags = SDistFlags {
    sDistSnapshot    = Flag False,
    sDistDirectory   = mempty,
    sDistDistPref    = NoFlag,
    sDistListSources = mempty,
    sDistVerbosity   = Flag normal
  }

sdistCommand :: CommandUI SDistFlags
sdistCommand = CommandUI
  { commandName         = "sdist"
  , commandSynopsis     =
      "Generate a source distribution file (.tar.gz)."
  , commandDescription  = Nothing
  , commandNotes        = Nothing
  , commandUsage        = \pname ->
      "Usage: " ++ pname ++ " sdist [FLAGS]\n"
  , commandDefaultFlags = defaultSDistFlags
  , commandOptions      = \showOrParseArgs ->
      [optionVerbosity sDistVerbosity (\v flags -> flags { sDistVerbosity = v })
      ,optionDistPref
         sDistDistPref (\d flags -> flags { sDistDistPref = d })
         showOrParseArgs

      ,option "" ["list-sources"]
         "Just write a list of the package's sources to a file"
         sDistListSources (\v flags -> flags { sDistListSources = v })
         (reqArgFlag "FILE")

      ,option "" ["snapshot"]
         "Produce a snapshot source distribution"
         sDistSnapshot (\v flags -> flags { sDistSnapshot = v })
         trueArg

      ,option "" ["output-directory"]
       ("Generate a source distribution in the given directory, "
        ++ "without creating a tarball")
         sDistDirectory (\v flags -> flags { sDistDirectory = v })
         (reqArgFlag "DIR")
      ]
  }

emptySDistFlags :: SDistFlags
emptySDistFlags = mempty

instance Monoid SDistFlags where
  mempty = gmempty
  mappend = (<>)

instance Semigroup SDistFlags where
  (<>) = gmappend

-- ------------------------------------------------------------
-- * Register flags
-- ------------------------------------------------------------

-- | Flags to @register@ and @unregister@: (user package, gen-script,
-- in-place, verbosity)
data RegisterFlags = RegisterFlags {
    regPackageDB   :: Flag PackageDB,
    regGenScript   :: Flag Bool,
    regGenPkgConf  :: Flag (Maybe FilePath),
    regInPlace     :: Flag Bool,
    regDistPref    :: Flag FilePath,
    regPrintId     :: Flag Bool,
    regVerbosity   :: Flag Verbosity,
    -- Same as in 'buildArgs' and 'copyArgs'
    regArgs        :: [String],
    regCabalFilePath :: Flag FilePath
  }
  deriving (Show, Generic, Typeable)

defaultRegisterFlags :: RegisterFlags
defaultRegisterFlags = RegisterFlags {
    regPackageDB   = NoFlag,
    regGenScript   = Flag False,
    regGenPkgConf  = NoFlag,
    regInPlace     = Flag False,
    regDistPref    = NoFlag,
    regPrintId     = Flag False,
    regArgs        = [],
    regCabalFilePath = mempty,
    regVerbosity   = Flag normal
  }

registerCommand :: CommandUI RegisterFlags
registerCommand = CommandUI
  { commandName         = "register"
  , commandSynopsis     =
      "Register this package with the compiler."
  , commandDescription  = Nothing
  , commandNotes        = Nothing
  , commandUsage        = \pname ->
      "Usage: " ++ pname ++ " register [FLAGS]\n"
  , commandDefaultFlags = defaultRegisterFlags
  , commandOptions      = \showOrParseArgs ->
      [optionVerbosity regVerbosity (\v flags -> flags { regVerbosity = v })
      ,optionDistPref
         regDistPref (\d flags -> flags { regDistPref = d })
         showOrParseArgs

      ,option "" ["packageDB"] ""
         regPackageDB (\v flags -> flags { regPackageDB = v })
         (choiceOpt [ (Flag UserPackageDB, ([],["user"]),
                                "upon registration, register this package in the user's local package database")
                    , (Flag GlobalPackageDB, ([],["global"]),
                                "(default)upon registration, register this package in the system-wide package database")])

      ,option "" ["inplace"]
         "register the package in the build location, so it can be used without being installed"
         regInPlace (\v flags -> flags { regInPlace = v })
         trueArg

      ,option "" ["gen-script"]
         "instead of registering, generate a script to register later"
         regGenScript (\v flags -> flags { regGenScript = v })
         trueArg

      ,option "" ["gen-pkg-config"]
         "instead of registering, generate a package registration file/directory"
         regGenPkgConf (\v flags -> flags { regGenPkgConf  = v })
         (optArg' "PKG" Flag flagToList)

      ,option "" ["print-ipid"]
         "print the installed package ID calculated for this package"
         regPrintId (\v flags -> flags { regPrintId = v })
         trueArg
      ]
  }

unregisterCommand :: CommandUI RegisterFlags
unregisterCommand = CommandUI
  { commandName         = "unregister"
  , commandSynopsis     =
      "Unregister this package with the compiler."
  , commandDescription  = Nothing
  , commandNotes        = Nothing
  , commandUsage        = \pname ->
      "Usage: " ++ pname ++ " unregister [FLAGS]\n"
  , commandDefaultFlags = defaultRegisterFlags
  , commandOptions      = \showOrParseArgs ->
      [optionVerbosity regVerbosity (\v flags -> flags { regVerbosity = v })
      ,optionDistPref
         regDistPref (\d flags -> flags { regDistPref = d })
          showOrParseArgs

      ,option "" ["user"] ""
         regPackageDB (\v flags -> flags { regPackageDB = v })
         (choiceOpt [ (Flag UserPackageDB, ([],["user"]),
                              "unregister this package in the user's local package database")
                    , (Flag GlobalPackageDB, ([],["global"]),
                              "(default) unregister this package in the  system-wide package database")])

      ,option "" ["gen-script"]
         "Instead of performing the unregister command, generate a script to unregister later"
         regGenScript (\v flags -> flags { regGenScript = v })
         trueArg
      ]
  }

emptyRegisterFlags :: RegisterFlags
emptyRegisterFlags = mempty

instance Monoid RegisterFlags where
  mempty = gmempty
  mappend = (<>)

instance Semigroup RegisterFlags where
  (<>) = gmappend

-- ------------------------------------------------------------
-- * HsColour flags
-- ------------------------------------------------------------

data HscolourFlags = HscolourFlags {
    hscolourCSS         :: Flag FilePath,
    hscolourExecutables :: Flag Bool,
    hscolourTestSuites  :: Flag Bool,
    hscolourBenchmarks  :: Flag Bool,
    hscolourForeignLibs :: Flag Bool,
    hscolourDistPref    :: Flag FilePath,
    hscolourVerbosity   :: Flag Verbosity,
    hscolourCabalFilePath :: Flag FilePath
    }
  deriving (Show, Generic, Typeable)

emptyHscolourFlags :: HscolourFlags
emptyHscolourFlags = mempty

defaultHscolourFlags :: HscolourFlags
defaultHscolourFlags = HscolourFlags {
    hscolourCSS         = NoFlag,
    hscolourExecutables = Flag False,
    hscolourTestSuites  = Flag False,
    hscolourBenchmarks  = Flag False,
    hscolourDistPref    = NoFlag,
    hscolourForeignLibs = Flag False,
    hscolourVerbosity   = Flag normal,
    hscolourCabalFilePath = mempty
  }

instance Monoid HscolourFlags where
  mempty = gmempty
  mappend = (<>)

instance Semigroup HscolourFlags where
  (<>) = gmappend

hscolourCommand :: CommandUI HscolourFlags
hscolourCommand = CommandUI
  { commandName         = "hscolour"
  , commandSynopsis     =
      "Generate HsColour colourised code, in HTML format."
  , commandDescription  = Just (\_ -> "Requires the hscolour program.\n")
  , commandNotes        = Just $ \_ ->
      "Deprecated in favour of 'cabal haddock --hyperlink-source'."
  , commandUsage        = \pname ->
      "Usage: " ++ pname ++ " hscolour [FLAGS]\n"
  , commandDefaultFlags = defaultHscolourFlags
  , commandOptions      = \showOrParseArgs ->
      [optionVerbosity hscolourVerbosity
       (\v flags -> flags { hscolourVerbosity = v })
      ,optionDistPref
         hscolourDistPref (\d flags -> flags { hscolourDistPref = d })
         showOrParseArgs

      ,option "" ["executables"]
         "Run hscolour for Executables targets"
         hscolourExecutables (\v flags -> flags { hscolourExecutables = v })
         trueArg

      ,option "" ["tests"]
         "Run hscolour for Test Suite targets"
         hscolourTestSuites (\v flags -> flags { hscolourTestSuites = v })
         trueArg

      ,option "" ["benchmarks"]
         "Run hscolour for Benchmark targets"
         hscolourBenchmarks (\v flags -> flags { hscolourBenchmarks = v })
         trueArg

      ,option "" ["foreign-libraries"]
         "Run hscolour for Foreign Library targets"
         hscolourForeignLibs (\v flags -> flags { hscolourForeignLibs = v })
         trueArg

      ,option "" ["all"]
         "Run hscolour for all targets"
         (\f -> allFlags [ hscolourExecutables f
                         , hscolourTestSuites  f
                         , hscolourBenchmarks  f
                         , hscolourForeignLibs f
                         ])
         (\v flags -> flags { hscolourExecutables = v
                            , hscolourTestSuites  = v
                            , hscolourBenchmarks  = v
                            , hscolourForeignLibs = v
                            })
         trueArg

      ,option "" ["css"]
         "Use a cascading style sheet"
         hscolourCSS (\v flags -> flags { hscolourCSS = v })
         (reqArgFlag "PATH")
      ]
  }

-- ------------------------------------------------------------
-- * Haddock flags
-- ------------------------------------------------------------


-- | When we build haddock documentation, there are two cases:
--
-- 1. We build haddocks only for the current development version,
--    intended for local use and not for distribution. In this case,
--    we store the generated documentation in @<dist>/doc/html/<package name>@.
--
-- 2. We build haddocks for intended for uploading them to hackage.
--    In this case, we need to follow the layout that hackage expects
--    from documentation tarballs, and we might also want to use different
--    flags than for development builds, so in this case we store the generated
--    documentation in @<dist>/doc/html/<package id>-docs@.
data HaddockTarget = ForHackage | ForDevelopment deriving (Eq, Show, Generic, Typeable)

instance Binary HaddockTarget
instance Structured HaddockTarget

instance Pretty HaddockTarget where
    pretty ForHackage     = Disp.text "for-hackage"
    pretty ForDevelopment = Disp.text "for-development"

instance Parsec HaddockTarget where
    parsec = P.choice [ P.try $ P.string "for-hackage"     >> return ForHackage
                      , P.string "for-development" >> return ForDevelopment]

data HaddockFlags = HaddockFlags {
    haddockProgramPaths :: [(String, FilePath)],
    haddockProgramArgs  :: [(String, [String])],
    haddockHoogle       :: Flag Bool,
    haddockHtml         :: Flag Bool,
    haddockHtmlLocation :: Flag String,
    haddockForHackage   :: Flag HaddockTarget,
    haddockExecutables  :: Flag Bool,
    haddockTestSuites   :: Flag Bool,
    haddockBenchmarks   :: Flag Bool,
    haddockForeignLibs  :: Flag Bool,
    haddockInternal     :: Flag Bool,
    haddockCss          :: Flag FilePath,
    haddockLinkedSource :: Flag Bool,
    haddockQuickJump    :: Flag Bool,
    haddockHscolourCss  :: Flag FilePath,
    haddockContents     :: Flag PathTemplate,
    haddockIndex        :: Flag PathTemplate,
    haddockDistPref     :: Flag FilePath,
    haddockKeepTempFiles:: Flag Bool,
    haddockVerbosity    :: Flag Verbosity,
    haddockCabalFilePath :: Flag FilePath,
    haddockBaseUrl      :: Flag String,
    haddockLib          :: Flag String,
    haddockArgs         :: [String]
  }
  deriving (Show, Generic, Typeable)

defaultHaddockFlags :: HaddockFlags
defaultHaddockFlags  = HaddockFlags {
    haddockProgramPaths = mempty,
    haddockProgramArgs  = [],
    haddockHoogle       = Flag False,
    haddockHtml         = Flag False,
    haddockHtmlLocation = NoFlag,
    haddockForHackage   = NoFlag,
    haddockExecutables  = Flag False,
    haddockTestSuites   = Flag False,
    haddockBenchmarks   = Flag False,
    haddockForeignLibs  = Flag False,
    haddockInternal     = Flag False,
    haddockCss          = NoFlag,
    haddockLinkedSource = Flag False,
    haddockQuickJump    = Flag False,
    haddockHscolourCss  = NoFlag,
    haddockContents     = NoFlag,
    haddockDistPref     = NoFlag,
    haddockKeepTempFiles= Flag False,
    haddockVerbosity    = Flag normal,
    haddockCabalFilePath = mempty,
    haddockIndex        = NoFlag,
    haddockBaseUrl      = NoFlag,
    haddockLib          = NoFlag,
    haddockArgs         = mempty
  }

haddockCommand :: CommandUI HaddockFlags
haddockCommand = CommandUI
  { commandName         = "haddock"
  , commandSynopsis     = "Generate Haddock HTML documentation."
  , commandDescription  = Just $ \_ ->
      "Requires the program haddock, version 2.x.\n"
  , commandNotes        = Nothing
  , commandUsage        = usageAlternatives "haddock" $
      [ "[FLAGS]"
      , "COMPONENTS [FLAGS]"
      ]
  , commandDefaultFlags = defaultHaddockFlags
  , commandOptions      = \showOrParseArgs ->
         haddockOptions showOrParseArgs
      ++ programDbPaths   progDb ParseArgs
             haddockProgramPaths (\v flags -> flags { haddockProgramPaths = v})
      ++ programDbOption  progDb showOrParseArgs
             haddockProgramArgs (\v fs -> fs { haddockProgramArgs = v })
      ++ programDbOptions progDb ParseArgs
             haddockProgramArgs  (\v flags -> flags { haddockProgramArgs = v})
  }
  where
    progDb = addKnownProgram haddockProgram
             $ addKnownProgram ghcProgram
             $ emptyProgramDb

haddockOptions :: ShowOrParseArgs -> [OptionField HaddockFlags]
haddockOptions showOrParseArgs =
  [optionVerbosity haddockVerbosity
   (\v flags -> flags { haddockVerbosity = v })
  ,optionDistPref
   haddockDistPref (\d flags -> flags { haddockDistPref = d })
   showOrParseArgs

  ,option "" ["keep-temp-files"]
   "Keep temporary files"
   haddockKeepTempFiles (\b flags -> flags { haddockKeepTempFiles = b })
   trueArg

  ,option "" ["hoogle"]
   "Generate a hoogle database"
   haddockHoogle (\v flags -> flags { haddockHoogle = v })
   trueArg

  ,option "" ["html"]
   "Generate HTML documentation (the default)"
   haddockHtml (\v flags -> flags { haddockHtml = v })
   trueArg

  ,option "" ["html-location"]
   "Location of HTML documentation for pre-requisite packages"
   haddockHtmlLocation (\v flags -> flags { haddockHtmlLocation = v })
   (reqArgFlag "URL")

  ,option "" ["for-hackage"]
   "Collection of flags to generate documentation suitable for upload to hackage"
   haddockForHackage (\v flags -> flags { haddockForHackage = v })
   (noArg (Flag ForHackage))

  ,option "" ["executables"]
   "Run haddock for Executables targets"
   haddockExecutables (\v flags -> flags { haddockExecutables = v })
   trueArg

  ,option "" ["tests"]
   "Run haddock for Test Suite targets"
   haddockTestSuites (\v flags -> flags { haddockTestSuites = v })
   trueArg

  ,option "" ["benchmarks"]
   "Run haddock for Benchmark targets"
   haddockBenchmarks (\v flags -> flags { haddockBenchmarks = v })
   trueArg

  ,option "" ["foreign-libraries"]
   "Run haddock for Foreign Library targets"
   haddockForeignLibs (\v flags -> flags { haddockForeignLibs = v })
   trueArg

  ,option "" ["all"]
   "Run haddock for all targets"
   (\f -> allFlags [ haddockExecutables f
                   , haddockTestSuites  f
                   , haddockBenchmarks  f
                   , haddockForeignLibs f
                   ])
         (\v flags -> flags { haddockExecutables = v
                            , haddockTestSuites  = v
                            , haddockBenchmarks  = v
                            , haddockForeignLibs = v
                            })
         trueArg

  ,option "" ["internal"]
   "Run haddock for internal modules and include all symbols"
   haddockInternal (\v flags -> flags { haddockInternal = v })
   trueArg

  ,option "" ["css"]
   "Use PATH as the haddock stylesheet"
   haddockCss (\v flags -> flags { haddockCss = v })
   (reqArgFlag "PATH")

  ,option "" ["hyperlink-source","hyperlink-sources","hyperlinked-source"]
   "Hyperlink the documentation to the source code"
   haddockLinkedSource (\v flags -> flags { haddockLinkedSource = v })
   trueArg

  ,option "" ["quickjump"]
   "Generate an index for interactive documentation navigation"
   haddockQuickJump (\v flags -> flags { haddockQuickJump = v })
   trueArg

  ,option "" ["hscolour-css"]
   "Use PATH as the HsColour stylesheet"
   haddockHscolourCss (\v flags -> flags { haddockHscolourCss = v })
   (reqArgFlag "PATH")

  ,option "" ["contents-location"]
   "Bake URL in as the location for the contents page"
   haddockContents (\v flags -> flags { haddockContents = v })
   (reqArg' "URL"
    (toFlag . toPathTemplate)
    (flagToList . fmap fromPathTemplate))

  ,option "" ["index-location"]
   "Use a separately-generated HTML index"
   haddockIndex (\v flags -> flags { haddockIndex = v})
   (reqArg' "URL"
    (toFlag . toPathTemplate)
    (flagToList . fmap fromPathTemplate))

  ,option "" ["base-url"]
   "Base URL for static files."
   haddockBaseUrl (\v flags -> flags { haddockBaseUrl = v})
   (reqArgFlag "URL")

  ,option "" ["lib"]
   "location of Haddocks static / auxiliary files"
   haddockLib (\v flags -> flags { haddockLib = v})
   (reqArgFlag "DIR")
  ]

emptyHaddockFlags :: HaddockFlags
emptyHaddockFlags = mempty

instance Monoid HaddockFlags where
  mempty = gmempty
  mappend = (<>)

instance Semigroup HaddockFlags where
  (<>) = gmappend

-- ------------------------------------------------------------
-- * HaddocksFlags flags
-- ------------------------------------------------------------

-- | Governs whether modules from a given interface should be visible or
-- hidden in the Haddock generated content page.  We don't expose this
-- functionality to the user, but simply use 'Visible' for only local packages.
-- Visibility of modules is available since @haddock-2.26.1@.
--
data Visibility = Visible | Hidden
  deriving (Eq, Show)

data HaddockProjectFlags = HaddockProjectFlags {
    haddockProjectHackage      :: Flag Bool,
    -- ^ a shortcut option which builds documentation linked to hackage.  It implies:
    -- * `--html-location='https://hackage.haskell.org/package/$prg-$version/docs'
    -- * `--quickjump`
    -- * `--gen-index`
    -- * `--gen-contents`
    -- * `--hyperlinked-source`
    haddockProjectLocal        :: Flag Bool,
    -- ^ a shortcut option which builds self contained directory which contains
    -- all the documentation, it implies:
    -- * `--quickjump`
    -- * `--gen-index`
    -- * `--gen-contents`
    -- * `--hyperlinked-source`
    --
    -- And it will also pass `--base-url` option to `haddock`.

    -- options passed to @haddock@ via 'createHaddockIndex'
    haddockProjectDir          :: Flag String,
    -- ^ output directory of combined haddocks, the default is './haddocks'
    haddockProjectPrologue     :: Flag String,
    haddockProjectGenIndex     :: Flag Bool,
    haddockProjectGenContents  :: Flag Bool,
    haddockProjectInterfaces   :: Flag [(FilePath, Maybe FilePath, Maybe FilePath, Visibility)],
    -- ^ 'haddocksInterfaces' is inferred by the 'haddocksAction'; currently not
    -- exposed to the user.

    -- options passed to @haddock@ via 'HaddockFlags' when building
    -- documentation

    haddockProjectProgramPaths :: [(String, FilePath)],
    haddockProjectProgramArgs  :: [(String, [String])],
    haddockProjectHoogle       :: Flag Bool,
    -- haddockHtml is not supported
    haddockProjectHtmlLocation :: Flag String,
    -- haddockForHackage is not supported
    haddockProjectExecutables  :: Flag Bool,
    haddockProjectTestSuites   :: Flag Bool,
    haddockProjectBenchmarks   :: Flag Bool,
    haddockProjectForeignLibs  :: Flag Bool,
    haddockProjectInternal     :: Flag Bool,
    haddockProjectCss          :: Flag FilePath,
    haddockProjectLinkedSource :: Flag Bool,
    haddockProjectQuickJump    :: Flag Bool,
    haddockProjectHscolourCss  :: Flag FilePath,
    -- haddockContent is not supported, a fixed value is provided
    -- haddockIndex is not supported, a fixed value is provided
    -- haddockDistPerf is not supported, note: it changes location of the haddocks
    haddockProjectKeepTempFiles:: Flag Bool,
    haddockProjectVerbosity    :: Flag Verbosity,
    -- haddockBaseUrl is not supported, a fixed value is provided
    haddockProjectLib          :: Flag String
  }
  deriving (Show, Generic, Typeable)

defaultHaddockProjectFlags :: HaddockProjectFlags
defaultHaddockProjectFlags = HaddockProjectFlags {
    haddockProjectHackage      = Flag False,
    haddockProjectLocal        = Flag False,
    haddockProjectDir          = Flag "./haddocks",
    haddockProjectPrologue     = NoFlag,
    haddockProjectGenIndex     = Flag False,
    haddockProjectGenContents  = Flag False,
    haddockProjectTestSuites   = Flag False,
    haddockProjectProgramPaths = mempty,
    haddockProjectProgramArgs  = mempty,
    haddockProjectHoogle       = Flag False,
    haddockProjectHtmlLocation = NoFlag,
    haddockProjectExecutables  = Flag False,
    haddockProjectBenchmarks   = Flag False,
    haddockProjectForeignLibs  = Flag False,
    haddockProjectInternal     = Flag False,
    haddockProjectCss          = NoFlag,
    haddockProjectLinkedSource = Flag False,
    haddockProjectQuickJump    = Flag False,
    haddockProjectHscolourCss  = NoFlag,
    haddockProjectKeepTempFiles= Flag False,
    haddockProjectVerbosity    = Flag normal,
    haddockProjectLib          = NoFlag,
    haddockProjectInterfaces   = NoFlag
  }

haddockProjectCommand :: CommandUI HaddockProjectFlags
haddockProjectCommand = CommandUI
  { commandName        = "v2-haddock-project"
  , commandSynopsis    = "Generate Haddocks HTML documentation for the cabal project."
  , commandDescription = Just $ \_ ->
      "Require the programm haddock, version 2.26.\n"
  , commandNotes       = Nothing
  , commandUsage       = usageAlternatives "haddocks" $
      [ "[FLAGS]"
      , "COMPONENTS [FLAGS]"
      ]
  , commandDefaultFlags = defaultHaddockProjectFlags
  , commandOptions      = \showOrParseArgs ->
         haddockProjectOptions showOrParseArgs
      ++ programDbPaths   progDb ParseArgs
             haddockProjectProgramPaths (\v flags -> flags { haddockProjectProgramPaths = v})
      ++ programDbOption  progDb showOrParseArgs
             haddockProjectProgramArgs (\v fs -> fs { haddockProjectProgramArgs = v })
      ++ programDbOptions progDb ParseArgs
             haddockProjectProgramArgs  (\v flags -> flags { haddockProjectProgramArgs = v})
  }
  where
    progDb = addKnownProgram haddockProgram
             $ addKnownProgram ghcProgram
             $ emptyProgramDb

haddockProjectOptions :: ShowOrParseArgs -> [OptionField HaddockProjectFlags]
haddockProjectOptions _showOrParseArgs =
    [option "" ["hackage"]
     (concat ["A short-cut option to build documentation linked to hackage; "
             ,"it implies --quickjump, --gen-index, --gen-contents, "
             ,"--hyperlinked-source and --html-location"
             ])
     haddockProjectHackage (\v flags -> flags { haddockProjectHackage = v })
     trueArg

    ,option "" ["local"]
     (concat ["A short-cut option to build self contained documentation; "
             ,"it implies  --quickjump, --gen-index, --gen-contents "
             ,"and --hyperlinked-source."
             ])
     haddockProjectLocal (\v flags -> flags { haddockProjectLocal = v })
     trueArg

    ,option "" ["output"]
      "Output directory"
      haddockProjectDir (\v flags -> flags { haddockProjectDir = v })
      (optArg' "DIRECTORY" maybeToFlag (fmap Just . flagToList))

    ,option "" ["prologue"]
     "File path to a prologue file in haddock format"
     haddockProjectPrologue (\v flags -> flags { haddockProjectPrologue = v})
     (optArg' "PATH" maybeToFlag (fmap Just . flagToList))

    ,option "" ["gen-index"]
     "Generate index"
     haddockProjectGenIndex (\v flags -> flags { haddockProjectGenIndex = v})
     trueArg

    ,option "" ["gen-contents"]
     "Generate contents"
     haddockProjectGenContents (\v flags -> flags { haddockProjectGenContents = v})
     trueArg

    ,option "" ["hoogle"]
     "Generate a hoogle database"
     haddockProjectHoogle (\v flags -> flags { haddockProjectHoogle = v })
     trueArg

    ,option "" ["html-location"]
     "Location of HTML documentation for pre-requisite packages"
     haddockProjectHtmlLocation (\v flags -> flags { haddockProjectHtmlLocation = v })
     (reqArgFlag "URL")

    ,option "" ["executables"]
     "Run haddock for Executables targets"
     haddockProjectExecutables (\v flags -> flags { haddockProjectExecutables = v })
     trueArg

    ,option "" ["tests"]
     "Run haddock for Test Suite targets"
     haddockProjectTestSuites (\v flags -> flags { haddockProjectTestSuites = v })
     trueArg

    ,option "" ["benchmarks"]
     "Run haddock for Benchmark targets"
     haddockProjectBenchmarks (\v flags -> flags { haddockProjectBenchmarks = v })
     trueArg

    ,option "" ["foreign-libraries"]
     "Run haddock for Foreign Library targets"
     haddockProjectForeignLibs (\v flags -> flags { haddockProjectForeignLibs = v })
     trueArg

    ,option "" ["internal"]
     "Run haddock for internal modules and include all symbols"
     haddockProjectInternal (\v flags -> flags { haddockProjectInternal = v })
     trueArg

    ,option "" ["css"]
     "Use PATH as the haddock stylesheet"
     haddockProjectCss (\v flags -> flags { haddockProjectCss = v })
     (reqArgFlag "PATH")

    ,option "" ["hyperlink-source","hyperlink-sources","hyperlinked-source"]
     "Hyperlink the documentation to the source code"
     haddockProjectLinkedSource (\v flags -> flags { haddockProjectLinkedSource = v })
     trueArg

    ,option "" ["quickjump"]
     "Generate an index for interactive documentation navigation"
     haddockProjectQuickJump (\v flags -> flags { haddockProjectQuickJump = v })
     trueArg

    ,option "" ["hscolour-css"]
     "Use PATH as the HsColour stylesheet"
     haddockProjectHscolourCss (\v flags -> flags { haddockProjectHscolourCss = v })
     (reqArgFlag "PATH")

    ,option "" ["keep-temp-files"]
     "Keep temporary files"
     haddockProjectKeepTempFiles (\b flags -> flags { haddockProjectKeepTempFiles = b })
     trueArg

    ,optionVerbosity haddockProjectVerbosity
     (\v flags -> flags { haddockProjectVerbosity = v })

    ,option "" ["lib"]
     "location of Haddocks static / auxiliary files"
     haddockProjectLib (\v flags -> flags { haddockProjectLib = v})
     (reqArgFlag "DIR")
    ]


emptyHaddockProjectFlags :: HaddockProjectFlags
emptyHaddockProjectFlags = mempty

instance Monoid HaddockProjectFlags where
  mempty = gmempty
  mappend = (<>)

instance Semigroup HaddockProjectFlags where
  (<>) = gmappend

-- ------------------------------------------------------------
-- * Clean flags
-- ------------------------------------------------------------

data CleanFlags = CleanFlags {
    cleanSaveConf  :: Flag Bool,
    cleanDistPref  :: Flag FilePath,
    cleanVerbosity :: Flag Verbosity,
    cleanCabalFilePath :: Flag FilePath
  }
  deriving (Show, Generic, Typeable)

defaultCleanFlags :: CleanFlags
defaultCleanFlags  = CleanFlags {
    cleanSaveConf  = Flag False,
    cleanDistPref  = NoFlag,
    cleanVerbosity = Flag normal,
    cleanCabalFilePath = mempty
  }

cleanCommand :: CommandUI CleanFlags
cleanCommand = CommandUI
  { commandName         = "clean"
  , commandSynopsis     = "Clean up after a build."
  , commandDescription  = Just $ \_ ->
      "Removes .hi, .o, preprocessed sources, etc.\n"
  , commandNotes        = Nothing
  , commandUsage        = \pname ->
      "Usage: " ++ pname ++ " clean [FLAGS]\n"
  , commandDefaultFlags = defaultCleanFlags
  , commandOptions      = \showOrParseArgs ->
      [optionVerbosity cleanVerbosity (\v flags -> flags { cleanVerbosity = v })
      ,optionDistPref
         cleanDistPref (\d flags -> flags { cleanDistPref = d })
         showOrParseArgs

      ,option "s" ["save-configure"]
         "Do not remove the configuration file (dist/setup-config) during cleaning.  Saves need to reconfigure."
         cleanSaveConf (\v flags -> flags { cleanSaveConf = v })
         trueArg
      ]
  }

emptyCleanFlags :: CleanFlags
emptyCleanFlags = mempty

instance Monoid CleanFlags where
  mempty = gmempty
  mappend = (<>)

instance Semigroup CleanFlags where
  (<>) = gmappend

-- ------------------------------------------------------------
-- * Build flags
-- ------------------------------------------------------------

data BuildFlags = BuildFlags {
    buildProgramPaths :: [(String, FilePath)],
    buildProgramArgs :: [(String, [String])],
    buildDistPref    :: Flag FilePath,
    buildVerbosity   :: Flag Verbosity,
    buildNumJobs     :: Flag (Maybe Int),
    -- TODO: this one should not be here, it's just that the silly
    -- UserHooks stop us from passing extra info in other ways
    buildArgs :: [String],
    buildCabalFilePath :: Flag FilePath
  }
  deriving (Read, Show, Generic, Typeable)

defaultBuildFlags :: BuildFlags
defaultBuildFlags  = BuildFlags {
    buildProgramPaths = mempty,
    buildProgramArgs = [],
    buildDistPref    = mempty,
    buildVerbosity   = Flag normal,
    buildNumJobs     = mempty,
    buildArgs        = [],
    buildCabalFilePath = mempty
  }

buildCommand :: ProgramDb -> CommandUI BuildFlags
buildCommand progDb = CommandUI
  { commandName         = "build"
  , commandSynopsis     = "Compile all/specific components."
  , commandDescription  = Just $ \_ -> wrapText $
         "Components encompass executables, tests, and benchmarks.\n"
      ++ "\n"
      ++ "Affected by configuration options, see `configure`.\n"
  , commandNotes        = Just $ \pname ->
       "Examples:\n"
        ++ "  " ++ pname ++ " build           "
        ++ "    All the components in the package\n"
        ++ "  " ++ pname ++ " build foo       "
        ++ "    A component (i.e. lib, exe, test suite)\n\n"
        ++ programFlagsDescription progDb
--TODO: re-enable once we have support for module/file targets
--        ++ "  " ++ pname ++ " build Foo.Bar   "
--        ++ "    A module\n"
--        ++ "  " ++ pname ++ " build Foo/Bar.hs"
--        ++ "    A file\n\n"
--        ++ "If a target is ambiguous it can be qualified with the component "
--        ++ "name, e.g.\n"
--        ++ "  " ++ pname ++ " build foo:Foo.Bar\n"
--        ++ "  " ++ pname ++ " build testsuite1:Foo/Bar.hs\n"
  , commandUsage        = usageAlternatives "build" $
      [ "[FLAGS]"
      , "COMPONENTS [FLAGS]"
      ]
  , commandDefaultFlags = defaultBuildFlags
  , commandOptions      = \showOrParseArgs ->
      [ optionVerbosity
        buildVerbosity (\v flags -> flags { buildVerbosity = v })

      , optionDistPref
        buildDistPref (\d flags -> flags { buildDistPref = d }) showOrParseArgs
      ]
      ++ buildOptions progDb showOrParseArgs
  }

buildOptions :: ProgramDb -> ShowOrParseArgs
                -> [OptionField BuildFlags]
buildOptions progDb showOrParseArgs =
  [ optionNumJobs
      buildNumJobs (\v flags -> flags { buildNumJobs = v })
  ]

  ++ programDbPaths progDb showOrParseArgs
       buildProgramPaths (\v flags -> flags { buildProgramPaths = v})

  ++ programDbOption progDb showOrParseArgs
       buildProgramArgs (\v fs -> fs { buildProgramArgs = v })

  ++ programDbOptions progDb showOrParseArgs
       buildProgramArgs (\v flags -> flags { buildProgramArgs = v})

emptyBuildFlags :: BuildFlags
emptyBuildFlags = mempty

instance Monoid BuildFlags where
  mempty = gmempty
  mappend = (<>)

instance Semigroup BuildFlags where
  (<>) = gmappend

-- ------------------------------------------------------------
-- * REPL Flags
-- ------------------------------------------------------------

data ReplOptions = ReplOptions {
    replOptionsFlags :: [String],
    replOptionsNoLoad :: Flag Bool
  }
  deriving (Show, Generic, Typeable)

instance Binary ReplOptions
instance Structured ReplOptions


instance Monoid ReplOptions where
  mempty = ReplOptions mempty (Flag False)
  mappend = (<>)

instance Semigroup ReplOptions where
  (<>) = gmappend

data ReplFlags = ReplFlags {
    replProgramPaths :: [(String, FilePath)],
    replProgramArgs :: [(String, [String])],
    replDistPref    :: Flag FilePath,
    replVerbosity   :: Flag Verbosity,
    replReload      :: Flag Bool,
    replReplOptions :: ReplOptions
  }
  deriving (Show, Generic, Typeable)

defaultReplFlags :: ReplFlags
defaultReplFlags  = ReplFlags {
    replProgramPaths = mempty,
    replProgramArgs = [],
    replDistPref    = NoFlag,
    replVerbosity   = Flag normal,
    replReload      = Flag False,
    replReplOptions = mempty
  }

instance Monoid ReplFlags where
  mempty = gmempty
  mappend = (<>)

instance Semigroup ReplFlags where
  (<>) = gmappend

replCommand :: ProgramDb -> CommandUI ReplFlags
replCommand progDb = CommandUI
  { commandName         = "repl"
  , commandSynopsis     =
      "Open an interpreter session for the given component."
  , commandDescription  = Just $ \pname -> wrapText $
         "If the current directory contains no package, ignores COMPONENT "
      ++ "parameters and opens an interactive interpreter session; if a "
      ++ "sandbox is present, its package database will be used.\n"
      ++ "\n"
      ++ "Otherwise, (re)configures with the given or default flags, and "
      ++ "loads the interpreter with the relevant modules. For executables, "
      ++ "tests and benchmarks, loads the main module (and its "
      ++ "dependencies); for libraries all exposed/other modules.\n"
      ++ "\n"
      ++ "The default component is the library itself, or the executable "
      ++ "if that is the only component.\n"
      ++ "\n"
      ++ "Support for loading specific modules is planned but not "
      ++ "implemented yet. For certain scenarios, `" ++ pname
      ++ " exec -- ghci :l Foo` may be used instead. Note that `exec` will "
      ++ "not (re)configure and you will have to specify the location of "
      ++ "other modules, if required.\n"

  , commandNotes        = Just $ \pname ->
         "Examples:\n"
      ++ "  " ++ pname ++ " repl           "
      ++ "    The first component in the package\n"
      ++ "  " ++ pname ++ " repl foo       "
      ++ "    A named component (i.e. lib, exe, test suite)\n"
      ++ "  " ++ pname ++ " repl --repl-options=\"-lstdc++\""
      ++ "  Specifying flags for interpreter\n"
--TODO: re-enable once we have support for module/file targets
--        ++ "  " ++ pname ++ " repl Foo.Bar   "
--        ++ "    A module\n"
--        ++ "  " ++ pname ++ " repl Foo/Bar.hs"
--        ++ "    A file\n\n"
--        ++ "If a target is ambiguous it can be qualified with the component "
--        ++ "name, e.g.\n"
--        ++ "  " ++ pname ++ " repl foo:Foo.Bar\n"
--        ++ "  " ++ pname ++ " repl testsuite1:Foo/Bar.hs\n"
  , commandUsage =  \pname -> "Usage: " ++ pname ++ " repl [COMPONENT] [FLAGS]\n"
  , commandDefaultFlags = defaultReplFlags
  , commandOptions = \showOrParseArgs ->
      optionVerbosity replVerbosity (\v flags -> flags { replVerbosity = v })
      : optionDistPref
          replDistPref (\d flags -> flags { replDistPref = d })
          showOrParseArgs

      : programDbPaths   progDb showOrParseArgs
          replProgramPaths (\v flags -> flags { replProgramPaths = v})

     ++ programDbOption progDb showOrParseArgs
          replProgramArgs (\v flags -> flags { replProgramArgs = v})

     ++ programDbOptions progDb showOrParseArgs
          replProgramArgs (\v flags -> flags { replProgramArgs = v})

     ++ case showOrParseArgs of
          ParseArgs ->
            [ option "" ["reload"]
              "Used from within an interpreter to update files."
              replReload (\v flags -> flags { replReload = v })
              trueArg
            ]
          _ -> []
     ++ map liftReplOption (replOptions showOrParseArgs)
  }
  where
    liftReplOption = liftOption replReplOptions (\v flags -> flags { replReplOptions = v })

replOptions :: ShowOrParseArgs -> [OptionField ReplOptions]
replOptions _ =
  [ option [] ["repl-no-load"]
    "Disable loading of project modules at REPL startup."
    replOptionsNoLoad (\p flags -> flags { replOptionsNoLoad = p })
    trueArg
  , option [] ["repl-options"]
    "Use the option(s) for the repl"
    replOptionsFlags (\p flags -> flags { replOptionsFlags = p })
    (reqArg "FLAG" (succeedReadE words) id)
  ]

-- ------------------------------------------------------------
-- * Test flags
-- ------------------------------------------------------------

data TestShowDetails = Never | Failures | Always | Streaming | Direct
    deriving (Eq, Ord, Enum, Bounded, Generic, Show, Typeable)

instance Binary TestShowDetails
instance Structured TestShowDetails

knownTestShowDetails :: [TestShowDetails]
knownTestShowDetails = [minBound..maxBound]

instance Pretty TestShowDetails where
    pretty  = Disp.text . lowercase . show

instance Parsec TestShowDetails where
    parsec = maybe (fail "invalid TestShowDetails") return . classify =<< ident
      where
        ident        = P.munch1 (\c -> isAlpha c || c == '_' || c == '-')
        classify str = lookup (lowercase str) enumMap
        enumMap     :: [(String, TestShowDetails)]
        enumMap      = [ (prettyShow x, x)
                       | x <- knownTestShowDetails ]

--TODO: do we need this instance?
instance Monoid TestShowDetails where
    mempty = Never
    mappend = (<>)

instance Semigroup TestShowDetails where
    a <> b = if a < b then b else a

data TestFlags = TestFlags {
    testDistPref    :: Flag FilePath,
    testVerbosity   :: Flag Verbosity,
    testHumanLog    :: Flag PathTemplate,
    testMachineLog  :: Flag PathTemplate,
    testShowDetails :: Flag TestShowDetails,
    testKeepTix     :: Flag Bool,
    testWrapper     :: Flag FilePath,
    testFailWhenNoTestSuites :: Flag Bool,
    -- TODO: think about if/how options are passed to test exes
    testOptions     :: [PathTemplate]
  } deriving (Show, Generic, Typeable)

defaultTestFlags :: TestFlags
defaultTestFlags  = TestFlags {
    testDistPref    = NoFlag,
    testVerbosity   = Flag normal,
    testHumanLog    = toFlag $ toPathTemplate $ "$pkgid-$test-suite.log",
    testMachineLog  = toFlag $ toPathTemplate $ "$pkgid.log",
    testShowDetails = toFlag Failures,
    testKeepTix     = toFlag False,
    testWrapper     = NoFlag,
    testFailWhenNoTestSuites = toFlag False,
    testOptions     = []
  }

testCommand :: CommandUI TestFlags
testCommand = CommandUI
  { commandName         = "test"
  , commandSynopsis     =
      "Run all/specific tests in the test suite."
  , commandDescription  = Just $ \ _pname -> wrapText $
      testOrBenchmarkHelpText "test"
  , commandNotes        = Nothing
  , commandUsage        = usageAlternatives "test"
      [ "[FLAGS]"
      , "TESTCOMPONENTS [FLAGS]"
      ]
  , commandDefaultFlags = defaultTestFlags
  , commandOptions = testOptions'
  }

-- | Help text for @test@ and @bench@ commands.
testOrBenchmarkHelpText
  :: String   -- ^ Either @"test"@ or @"benchmark"@.
  -> String   -- ^ Help text.
testOrBenchmarkHelpText s = unlines $ map unwords
  [ [ "The package must have been build with configuration"
    , concat [ "flag `--enable-", s, "s`." ]
    ]
  , []  -- blank line
  , [ concat [ "Note that additional dependencies of the ", s, "s" ]
    , "must have already been installed."
    ]
  , []
  , [ "By defining UserHooks in a custom Setup.hs, the package can define"
    , concat [ "actions to be executed before and after running ", s, "s." ]
    ]
  ]

testOptions' ::  ShowOrParseArgs -> [OptionField TestFlags]
testOptions' showOrParseArgs =
  [ optionVerbosity testVerbosity (\v flags -> flags { testVerbosity = v })
  , optionDistPref
        testDistPref (\d flags -> flags { testDistPref = d })
        showOrParseArgs
  , option [] ["log"]
        ("Log all test suite results to file (name template can use "
        ++ "$pkgid, $compiler, $os, $arch, $test-suite, $result)")
        testHumanLog (\v flags -> flags { testHumanLog = v })
        (reqArg' "TEMPLATE"
            (toFlag . toPathTemplate)
            (flagToList . fmap fromPathTemplate))
  , option [] ["machine-log"]
        ("Produce a machine-readable log file (name template can use "
        ++ "$pkgid, $compiler, $os, $arch, $result)")
        testMachineLog (\v flags -> flags { testMachineLog = v })
        (reqArg' "TEMPLATE"
            (toFlag . toPathTemplate)
            (flagToList . fmap fromPathTemplate))
  , option [] ["show-details"]
        ("'always': always show results of individual test cases. "
         ++ "'never': never show results of individual test cases. "
         ++ "'failures': show results of failing test cases. "
         ++ "'streaming': show results of test cases in real time."
         ++ "'direct': send results of test cases in real time; no log file.")
        testShowDetails (\v flags -> flags { testShowDetails = v })
        (reqArg "FILTER"
            (parsecToReadE (\_ -> "--show-details flag expects one of "
                          ++ intercalate ", "
                               (map prettyShow knownTestShowDetails))
                        (fmap toFlag parsec))
            (flagToList . fmap prettyShow))
  , option [] ["keep-tix-files"]
        "keep .tix files for HPC between test runs"
        testKeepTix (\v flags -> flags { testKeepTix = v})
        trueArg
  , option [] ["test-wrapper"]
        "Run test through a wrapper."
        testWrapper (\v flags -> flags { testWrapper = v })
        (reqArg' "FILE" (toFlag :: FilePath -> Flag FilePath)
            (flagToList :: Flag FilePath -> [FilePath]))
  , option [] ["fail-when-no-test-suites"]
        ("Exit with failure when no test suites are found.")
        testFailWhenNoTestSuites (\v flags -> flags { testFailWhenNoTestSuites = v})
        trueArg
  , option [] ["test-options"]
        ("give extra options to test executables "
         ++ "(name templates can use $pkgid, $compiler, "
         ++ "$os, $arch, $test-suite)")
        testOptions (\v flags -> flags { testOptions = v })
        (reqArg' "TEMPLATES" (map toPathTemplate . splitArgs)
            (const []))
  , option [] ["test-option"]
        ("give extra option to test executables "
         ++ "(no need to quote options containing spaces, "
         ++ "name template can use $pkgid, $compiler, "
         ++ "$os, $arch, $test-suite)")
        testOptions (\v flags -> flags { testOptions = v })
        (reqArg' "TEMPLATE" (\x -> [toPathTemplate x])
            (map fromPathTemplate))
  ]

emptyTestFlags :: TestFlags
emptyTestFlags  = mempty

instance Monoid TestFlags where
  mempty = gmempty
  mappend = (<>)

instance Semigroup TestFlags where
  (<>) = gmappend

-- ------------------------------------------------------------
-- * Benchmark flags
-- ------------------------------------------------------------

data BenchmarkFlags = BenchmarkFlags {
    benchmarkDistPref  :: Flag FilePath,
    benchmarkVerbosity :: Flag Verbosity,
    benchmarkOptions   :: [PathTemplate]
  } deriving (Show, Generic, Typeable)

defaultBenchmarkFlags :: BenchmarkFlags
defaultBenchmarkFlags  = BenchmarkFlags {
    benchmarkDistPref  = NoFlag,
    benchmarkVerbosity = Flag normal,
    benchmarkOptions   = []
  }

benchmarkCommand :: CommandUI BenchmarkFlags
benchmarkCommand = CommandUI
  { commandName         = "bench"
  , commandSynopsis     =
      "Run all/specific benchmarks."
  , commandDescription  = Just $ \ _pname -> wrapText $
      testOrBenchmarkHelpText "benchmark"
  , commandNotes        = Nothing
  , commandUsage        = usageAlternatives "bench"
      [ "[FLAGS]"
      , "BENCHCOMPONENTS [FLAGS]"
      ]
  , commandDefaultFlags = defaultBenchmarkFlags
  , commandOptions = benchmarkOptions'
  }

benchmarkOptions' :: ShowOrParseArgs -> [OptionField BenchmarkFlags]
benchmarkOptions' showOrParseArgs =
  [ optionVerbosity benchmarkVerbosity
    (\v flags -> flags { benchmarkVerbosity = v })
  , optionDistPref
        benchmarkDistPref (\d flags -> flags { benchmarkDistPref = d })
        showOrParseArgs
  , option [] ["benchmark-options"]
        ("give extra options to benchmark executables "
         ++ "(name templates can use $pkgid, $compiler, "
         ++ "$os, $arch, $benchmark)")
        benchmarkOptions (\v flags -> flags { benchmarkOptions = v })
        (reqArg' "TEMPLATES" (map toPathTemplate . splitArgs)
            (const []))
  , option [] ["benchmark-option"]
        ("give extra option to benchmark executables "
         ++ "(no need to quote options containing spaces, "
         ++ "name template can use $pkgid, $compiler, "
         ++ "$os, $arch, $benchmark)")
        benchmarkOptions (\v flags -> flags { benchmarkOptions = v })
        (reqArg' "TEMPLATE" (\x -> [toPathTemplate x])
            (map fromPathTemplate))
  ]

emptyBenchmarkFlags :: BenchmarkFlags
emptyBenchmarkFlags = mempty

instance Monoid BenchmarkFlags where
  mempty = gmempty
  mappend = (<>)

instance Semigroup BenchmarkFlags where
  (<>) = gmappend

-- ------------------------------------------------------------
-- * Shared options utils
-- ------------------------------------------------------------

programFlagsDescription :: ProgramDb -> String
programFlagsDescription progDb =
     "The flags --with-PROG and --PROG-option(s) can be used with"
  ++ " the following programs:"
  ++ (concatMap (\line -> "\n  " ++ unwords line) . wrapLine 77 . sort)
     [ programName prog | (prog, _) <- knownPrograms progDb ]
  ++ "\n"

-- | For each known program @PROG@ in 'progDb', produce a @with-PROG@
-- 'OptionField'.
programDbPaths
  :: ProgramDb
  -> ShowOrParseArgs
  -> (flags -> [(String, FilePath)])
  -> ([(String, FilePath)] -> (flags -> flags))
  -> [OptionField flags]
programDbPaths progDb showOrParseArgs get set =
  programDbPaths' ("with-" ++) progDb showOrParseArgs get set

-- | Like 'programDbPaths', but allows to customise the option name.
programDbPaths'
  :: (String -> String)
  -> ProgramDb
  -> ShowOrParseArgs
  -> (flags -> [(String, FilePath)])
  -> ([(String, FilePath)] -> (flags -> flags))
  -> [OptionField flags]
programDbPaths' mkName progDb showOrParseArgs get set =
  case showOrParseArgs of
    -- we don't want a verbose help text list so we just show a generic one:
    ShowArgs  -> [withProgramPath "PROG"]
    ParseArgs -> map (withProgramPath . programName . fst)
                 (knownPrograms progDb)
  where
    withProgramPath prog =
      option "" [mkName prog]
        ("give the path to " ++ prog)
        get set
        (reqArg' "PATH" (\path -> [(prog, path)])
          (\progPaths -> [ path | (prog', path) <- progPaths, prog==prog' ]))

-- | For each known program @PROG@ in 'progDb', produce a @PROG-option@
-- 'OptionField'.
programDbOption
  :: ProgramDb
  -> ShowOrParseArgs
  -> (flags -> [(String, [String])])
  -> ([(String, [String])] -> (flags -> flags))
  -> [OptionField flags]
programDbOption progDb showOrParseArgs get set =
  case showOrParseArgs of
    -- we don't want a verbose help text list so we just show a generic one:
    ShowArgs  -> [programOption "PROG"]
    ParseArgs -> map (programOption  . programName . fst)
                 (knownPrograms progDb)
  where
    programOption prog =
      option "" [prog ++ "-option"]
        ("give an extra option to " ++ prog ++
         " (no need to quote options containing spaces)")
        get set
        (reqArg' "OPT" (\arg -> [(prog, [arg])])
           (\progArgs -> concat [ args
                                | (prog', args) <- progArgs, prog==prog' ]))


-- | For each known program @PROG@ in 'progDb', produce a @PROG-options@
-- 'OptionField'.
programDbOptions
  :: ProgramDb
  -> ShowOrParseArgs
  -> (flags -> [(String, [String])])
  -> ([(String, [String])] -> (flags -> flags))
  -> [OptionField flags]
programDbOptions progDb showOrParseArgs get set =
  case showOrParseArgs of
    -- we don't want a verbose help text list so we just show a generic one:
    ShowArgs  -> [programOptions  "PROG"]
    ParseArgs -> map (programOptions . programName . fst)
                 (knownPrograms progDb)
  where
    programOptions prog =
      option "" [prog ++ "-options"]
        ("give extra options to " ++ prog)
        get set
        (reqArg' "OPTS" (\args -> [(prog, splitArgs args)]) (const []))

-- ------------------------------------------------------------
-- * GetOpt Utils
-- ------------------------------------------------------------

boolOpt :: SFlags -> SFlags
           -> MkOptDescr (a -> Flag Bool) (Flag Bool -> a -> a) a
boolOpt  = Command.boolOpt  flagToMaybe Flag

boolOpt' :: OptFlags -> OptFlags
            -> MkOptDescr (a -> Flag Bool) (Flag Bool -> a -> a) a
boolOpt' = Command.boolOpt' flagToMaybe Flag

trueArg, falseArg :: MkOptDescr (a -> Flag Bool) (Flag Bool -> a -> a) a
trueArg  sfT lfT = boolOpt' (sfT, lfT) ([], [])   sfT lfT
falseArg sfF lfF = boolOpt' ([],  [])  (sfF, lfF) sfF lfF

reqArgFlag :: ArgPlaceHolder -> SFlags -> LFlags -> Description ->
              (b -> Flag String) -> (Flag String -> b -> b) -> OptDescr b
reqArgFlag ad = reqArg ad (succeedReadE Flag) flagToList

optionDistPref :: (flags -> Flag FilePath)
               -> (Flag FilePath -> flags -> flags)
               -> ShowOrParseArgs
               -> OptionField flags
optionDistPref get set = \showOrParseArgs ->
  option "" (distPrefFlagName showOrParseArgs)
    (   "The directory where Cabal puts generated build files "
     ++ "(default " ++ defaultDistPref ++ ")")
    get set
    (reqArgFlag "DIR")
  where
    distPrefFlagName ShowArgs  = ["builddir"]
    distPrefFlagName ParseArgs = ["builddir", "distdir", "distpref"]

optionVerbosity :: (flags -> Flag Verbosity)
                -> (Flag Verbosity -> flags -> flags)
                -> OptionField flags
optionVerbosity get set =
  option "v" ["verbose"]
    "Control verbosity (n is 0--3, default verbosity level is 1)"
    get set
    (optArg "n" (fmap Flag flagToVerbosity)
                (Flag verbose) -- default Value if no n is given
                (fmap (Just . showForCabal) . flagToList))

optionNumJobs :: (flags -> Flag (Maybe Int))
              -> (Flag (Maybe Int) -> flags -> flags)
              -> OptionField flags
optionNumJobs get set =
  option "j" ["jobs"]
    "Run NUM jobs simultaneously (or '$ncpus' if no NUM is given)."
    get set
    (optArg "NUM" (fmap Flag numJobsParser)
                  (Flag Nothing)
                  (map (Just . maybe "$ncpus" show) . flagToList))
  where
    numJobsParser :: ReadE (Maybe Int)
    numJobsParser = ReadE $ \s ->
      case s of
        "$ncpus" -> Right Nothing
        _        -> case reads s of
          [(n, "")]
            | n < 1     -> Left "The number of jobs should be 1 or more."
            | otherwise -> Right (Just n)
          _             -> Left "The jobs value should be a number or '$ncpus'"

-- ------------------------------------------------------------
-- * Other Utils
-- ------------------------------------------------------------

-- | Arguments to pass to a @configure@ script, e.g. generated by
-- @autoconf@.
configureArgs :: Bool -> ConfigFlags -> [String]
configureArgs bcHack flags
  = hc_flag
 ++ optFlag  "with-hc-pkg" configHcPkg
 ++ optFlag' "prefix"      prefix
 ++ optFlag' "bindir"      bindir
 ++ optFlag' "libdir"      libdir
 ++ optFlag' "libexecdir"  libexecdir
 ++ optFlag' "datadir"     datadir
 ++ optFlag' "sysconfdir"  sysconfdir
 ++ configConfigureArgs flags
  where
        hc_flag = case (configHcFlavor flags, configHcPath flags) of
                        (_, Flag hc_path) -> [hc_flag_name ++ hc_path]
                        (Flag hc, NoFlag) -> [hc_flag_name ++ prettyShow hc]
                        (NoFlag,NoFlag)   -> []
        hc_flag_name
            --TODO kill off thic bc hack when defaultUserHooks is removed.
            | bcHack    = "--with-hc="
            | otherwise = "--with-compiler="
        optFlag name config_field = case config_field flags of
                        Flag p -> ["--" ++ name ++ "=" ++ p]
                        NoFlag -> []
        optFlag' name config_field = optFlag name (fmap fromPathTemplate
                                                 . config_field
                                                 . configInstallDirs)

configureCCompiler :: Verbosity -> ProgramDb
                      -> IO (FilePath, [String])
configureCCompiler verbosity progdb = configureProg verbosity progdb gccProgram

configureLinker :: Verbosity -> ProgramDb -> IO (FilePath, [String])
configureLinker verbosity progdb = configureProg verbosity progdb ldProgram

configureProg :: Verbosity -> ProgramDb -> Program
                 -> IO (FilePath, [String])
configureProg verbosity programDb prog = do
    (p, _) <- requireProgram verbosity prog programDb
    let pInv = programInvocation p []
    return (progInvokePath pInv, progInvokeArgs pInv)

-- | Helper function to split a string into a list of arguments.
-- It's supposed to handle quoted things sensibly, eg:
--
-- > splitArgs "--foo=\"C:/Program Files/Bar/" --baz"
-- >   = ["--foo=C:/Program Files/Bar", "--baz"]
--
-- > splitArgs "\"-DMSGSTR=\\\"foo bar\\\"\" --baz"
-- >   = ["-DMSGSTR=\"foo bar\"","--baz"]
--
splitArgs :: String -> [String]
splitArgs  = space []
  where
    space :: String -> String -> [String]
    space w []      = word w []
    space w ( c :s)
        | isSpace c = word w (space [] s)
    space w ('"':s) = string w s
    space w s       = nonstring w s

    string :: String -> String -> [String]
    string w []      = word w []
    string w ('"':s) = space w s
    string w ('\\':'"':s) = string ('"':w) s
    string w ( c :s) = string (c:w) s

    nonstring :: String -> String -> [String]
    nonstring w  []      = word w []
    nonstring w  ('"':s) = string w s
    nonstring w  ( c :s) = space (c:w) s

    word [] s = s
    word w  s = reverse w : s

-- The test cases kinda have to be rewritten from the ground up... :/
--hunitTests :: [Test]
--hunitTests =
--    let m = [("ghc", GHC), ("nhc98", NHC), ("hugs", Hugs)]
--        (flags, commands', unkFlags, ers)
--               = getOpt Permute options ["configure", "foobar", "--prefix=/foo", "--ghc", "--nhc98", "--hugs", "--with-compiler=/comp", "--unknown1", "--unknown2", "--install-prefix=/foo", "--user", "--global"]
--       in  [TestLabel "very basic option parsing" $ TestList [
--                 "getOpt flags" ~: "failed" ~:
--                 [Prefix "/foo", GhcFlag, NhcFlag, HugsFlag,
--                  WithCompiler "/comp", InstPrefix "/foo", UserFlag, GlobalFlag]
--                 ~=? flags,
--                 "getOpt commands" ~: "failed" ~: ["configure", "foobar"] ~=? commands',
--                 "getOpt unknown opts" ~: "failed" ~:
--                      ["--unknown1", "--unknown2"] ~=? unkFlags,
--                 "getOpt errors" ~: "failed" ~: [] ~=? ers],
--
--               TestLabel "test location of various compilers" $ TestList
--               ["configure parsing for prefix and compiler flag" ~: "failed" ~:
--                    (Right (ConfigCmd (Just comp, Nothing, Just "/usr/local"), []))
--                   ~=? (parseArgs ["--prefix=/usr/local", "--"++name, "configure"])
--                   | (name, comp) <- m],
--
--               TestLabel "find the package tool" $ TestList
--               ["configure parsing for prefix comp flag, withcompiler" ~: "failed" ~:
--                    (Right (ConfigCmd (Just comp, Just "/foo/comp", Just "/usr/local"), []))
--                   ~=? (parseArgs ["--prefix=/usr/local", "--"++name,
--                                   "--with-compiler=/foo/comp", "configure"])
--                   | (name, comp) <- m],
--
--               TestLabel "simpler commands" $ TestList
--               [flag ~: "failed" ~: (Right (flagCmd, [])) ~=? (parseArgs [flag])
--                   | (flag, flagCmd) <- [("build", BuildCmd),
--                                         ("install", InstallCmd Nothing False),
--                                         ("sdist", SDistCmd),
--                                         ("register", RegisterCmd False)]
--                  ]
--               ]

{- Testing ideas:
   * IO to look for hugs and hugs-pkg (which hugs, etc)
   * quickCheck to test permutations of arguments
   * what other options can we over-ride with a command-line flag?
-}
