--
-- (c) The University of Glasgow, 2004
--

-- | Package configuration information: essentially the interface to Cabal, with some utilities
module PackageConfig (
    -- $package_naming
    
	-- * PackageId
	mkPackageId, packageConfigId, unpackPackageId,
	
	-- * The PackageConfig type: information about a package
	PackageConfig,
	InstalledPackageInfo_(..), display,
	Version(..),
	PackageIdentifier(..),
	defaultPackageConfig,
    packageConfigToInstalledPackageInfo,
    installedPackageInfoToPackageConfig,
  ) where

#include "HsVersions.h"

import Data.Maybe
import Module
import Distribution.InstalledPackageInfo
import Distribution.ModuleName
import Distribution.Package hiding (PackageId)
import Distribution.Text
import Distribution.Version
import Distribution.Compat.ReadP

-- -----------------------------------------------------------------------------
-- Our PackageConfig type is just InstalledPackageInfo from Cabal.  Later we
-- might need to extend it with some GHC-specific stuff, but for now it's fine.

type PackageConfig = InstalledPackageInfo_ Module.ModuleName
defaultPackageConfig :: PackageConfig
defaultPackageConfig = emptyInstalledPackageInfo

-- -----------------------------------------------------------------------------
-- PackageId (package names with versions)

-- $package_naming
-- #package_naming#
-- Mostly the compiler deals in terms of 'PackageName's, which don't
-- have the version suffix.  This is so that we don't need to know the
-- version for the @-package-name@ flag, or know the versions of
-- wired-in packages like @base@ & @rts@.  Versions are confined to the
-- package sub-system.
--
-- This means that in theory you could have multiple base packages installed
-- (for example), and switch between them using @-package@\/@-hide-package@.
--
-- A 'PackageId' is a string of the form @<pkg>-<version>@.

-- | Turn a Cabal 'PackageIdentifier' into a GHC 'PackageId'
mkPackageId :: PackageIdentifier -> PackageId
mkPackageId = stringToPackageId . display

-- | Get the GHC 'PackageId' right out of a Cabalish 'PackageConfig'
packageConfigId :: PackageConfig -> PackageId
packageConfigId = mkPackageId . package

-- | Try and interpret a GHC 'PackageId' as a cabal 'PackageIdentifer'. Returns @Nothing@ if
-- we could not parse it as such an object.
unpackPackageId :: PackageId -> Maybe PackageIdentifier
unpackPackageId p
  = case [ pid | (pid,"") <- readP_to_S parse str ] of
        []      -> Nothing
        (pid:_) -> Just pid
  where str = packageIdString p

-- | Turn a 'PackageConfig', which contains GHC 'ModuleName's into a Cabal specific
-- 'InstalledPackageInfo' which contains Cabal 'Distribution.ModuleName.ModuleName's
packageConfigToInstalledPackageInfo :: PackageConfig -> InstalledPackageInfo
packageConfigToInstalledPackageInfo
    (pkgconf@(InstalledPackageInfo { exposedModules = e,
                                     hiddenModules = h })) =
        pkgconf{ exposedModules = map convert e,
                 hiddenModules  = map convert h }
    where convert :: Module.ModuleName -> Distribution.ModuleName.ModuleName
          convert = fromJust . simpleParse . moduleNameString

-- | Turn an 'InstalledPackageInfo', which contains Cabal 'Distribution.ModuleName.ModuleName's
-- into a GHC specific 'PackageConfig' which contains GHC 'ModuleName's
installedPackageInfoToPackageConfig :: InstalledPackageInfo -> PackageConfig
installedPackageInfoToPackageConfig
    (pkgconf@(InstalledPackageInfo { exposedModules = e,
                                     hiddenModules = h })) =
        pkgconf{ exposedModules = map convert e,
                 hiddenModules  = map convert h }
    where convert :: Distribution.ModuleName.ModuleName -> Module.ModuleName
          convert = mkModuleName . display