{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE RankNTypes #-}

-----------------------------------------------------------------------------
-- |
-- Module      :  Distribution.Simple.Program.HcPkg
-- Copyright   :  Duncan Coutts 2009, 2013
--
-- Maintainer  :  cabal-devel@haskell.org
-- Portability :  portable
--
-- This module provides an library interface to the @hc-pkg@ program.
-- Currently only GHC, GHCJS and LHC have hc-pkg programs.

module Distribution.Simple.Program.HcPkg (
    -- * Types
    HcPkgInfo(..),
    RegisterOptions(..),
    defaultRegisterOptions,

    -- * Actions
    init,
    invoke,
    register,
    unregister,
    recache,
    expose,
    hide,
    dump,
    describe,
    list,

    -- * Program invocations
    initInvocation,
    registerInvocation,
    unregisterInvocation,
    recacheInvocation,
    exposeInvocation,
    hideInvocation,
    dumpInvocation,
    describeInvocation,
    listInvocation,
  ) where

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

import Distribution.InstalledPackageInfo
import Distribution.ParseUtils
import Distribution.Simple.Compiler
import Distribution.Simple.Program.Types
import Distribution.Simple.Program.Run
import Distribution.Simple.Utils
import Distribution.Text
import Distribution.Types.ComponentId
import Distribution.Types.PackageId
import Distribution.Types.UnitId
import Distribution.Verbosity
import Distribution.Compat.Exception

import Data.List
         ( stripPrefix )
import System.FilePath as FilePath
         ( (</>), (<.>)
         , splitPath, splitDirectories, joinPath, isPathSeparator )
import qualified System.FilePath.Posix as FilePath.Posix

-- | Information about the features and capabilities of an @hc-pkg@
--   program.
--
data HcPkgInfo = HcPkgInfo
  { hcPkgProgram    :: ConfiguredProgram
  , noPkgDbStack    :: Bool -- ^ no package DB stack supported
  , noVerboseFlag   :: Bool -- ^ hc-pkg does not support verbosity flags
  , flagPackageConf :: Bool -- ^ use package-conf option instead of package-db
  , supportsDirDbs  :: Bool -- ^ supports directory style package databases
  , requiresDirDbs  :: Bool -- ^ requires directory style package databases
  , nativeMultiInstance  :: Bool -- ^ supports --enable-multi-instance flag
  , recacheMultiInstance :: Bool -- ^ supports multi-instance via recache
  , suppressFilesCheck   :: Bool -- ^ supports --force-files or equivalent
  }


-- | Call @hc-pkg@ to initialise a package database at the location {path}.
--
-- > hc-pkg init {path}
--
init :: HcPkgInfo -> Verbosity -> Bool -> FilePath -> IO ()
init hpi verbosity preferCompat path
  |  not (supportsDirDbs hpi)
 || (not (requiresDirDbs hpi) && preferCompat)
  = writeFile path "[]"

  | otherwise
  = runProgramInvocation verbosity (initInvocation hpi verbosity path)

-- | Run @hc-pkg@ using a given package DB stack, directly forwarding the
-- provided command-line arguments to it.
invoke :: HcPkgInfo -> Verbosity -> PackageDBStack -> [String] -> IO ()
invoke hpi verbosity dbStack extraArgs =
  runProgramInvocation verbosity invocation
  where
    args       = packageDbStackOpts hpi dbStack ++ extraArgs
    invocation = programInvocation (hcPkgProgram hpi) args

-- | Additional variations in the behaviour for 'register'.
data RegisterOptions = RegisterOptions {
       -- | Allows re-registering \/ overwriting an existing package
       registerAllowOverwrite     :: Bool,

       -- | Insist on the ability to register multiple instances of a
       -- single version of a single package. This will fail if the @hc-pkg@
       -- does not support it, see 'nativeMultiInstance' and
       -- 'recacheMultiInstance'.
       registerMultiInstance      :: Bool,

       -- | Require that no checks are performed on the existence of package
       -- files mentioned in the registration info. This must be used if
       -- registering prior to putting the files in their final place. This will
       -- fail if the @hc-pkg@ does not support it, see 'suppressFilesCheck'.
       registerSuppressFilesCheck :: Bool
     }

-- | Defaults are @True@, @False@ and @False@
defaultRegisterOptions :: RegisterOptions
defaultRegisterOptions = RegisterOptions {
    registerAllowOverwrite     = True,
    registerMultiInstance      = False,
    registerSuppressFilesCheck = False
  }

-- | Call @hc-pkg@ to register a package.
--
-- > hc-pkg register {filename | -} [--user | --global | --package-db]
--
register :: HcPkgInfo -> Verbosity -> PackageDBStack
         -> InstalledPackageInfo
         -> RegisterOptions
         -> IO ()
register hpi verbosity packagedbs pkgInfo registerOptions
  | registerMultiInstance registerOptions
  , not (nativeMultiInstance hpi || recacheMultiInstance hpi)
  = die' verbosity $ "HcPkg.register: the compiler does not support "
       ++ "registering multiple instances of packages."

  | registerSuppressFilesCheck registerOptions
  , not (suppressFilesCheck hpi)
  = die' verbosity $ "HcPkg.register: the compiler does not support "
                  ++ "suppressing checks on files."

    -- This is a trick. Older versions of GHC do not support the
    -- --enable-multi-instance flag for ghc-pkg register but it turns out that
    -- the same ability is available by using ghc-pkg recache. The recache
    -- command is there to support distro package managers that like to work
    -- by just installing files and running update commands, rather than
    -- special add/remove commands. So the way to register by this method is
    -- to write the package registration file directly into the package db and
    -- then call hc-pkg recache.
    --
  | registerMultiInstance registerOptions
  , recacheMultiInstance hpi
  = do let pkgdb = last packagedbs
       writeRegistrationFileDirectly verbosity hpi pkgdb pkgInfo
       recache hpi verbosity pkgdb

  | otherwise
  = runProgramInvocation verbosity
      (registerInvocation hpi verbosity packagedbs pkgInfo registerOptions)

writeRegistrationFileDirectly :: Verbosity
                              -> HcPkgInfo
                              -> PackageDB
                              -> InstalledPackageInfo
                              -> IO ()
writeRegistrationFileDirectly verbosity hpi (SpecificPackageDB dir) pkgInfo
  | supportsDirDbs hpi
  = do let pkgfile = dir </> display (installedUnitId pkgInfo) <.> "conf"
       writeUTF8File pkgfile (showInstalledPackageInfo pkgInfo)

  | otherwise
  = die' verbosity $ "HcPkg.writeRegistrationFileDirectly: compiler does not support dir style package dbs"

writeRegistrationFileDirectly verbosity _ _ _ =
    -- We don't know here what the dir for the global or user dbs are,
    -- if that's needed it'll require a bit more plumbing to support.
    die' verbosity $ "HcPkg.writeRegistrationFileDirectly: only supports SpecificPackageDB for now"


-- | Call @hc-pkg@ to unregister a package
--
-- > hc-pkg unregister [pkgid] [--user | --global | --package-db]
--
unregister :: HcPkgInfo -> Verbosity -> PackageDB -> PackageId -> IO ()
unregister hpi verbosity packagedb pkgid =
  runProgramInvocation verbosity
    (unregisterInvocation hpi verbosity packagedb pkgid)


-- | Call @hc-pkg@ to recache the registered packages.
--
-- > hc-pkg recache [--user | --global | --package-db]
--
recache :: HcPkgInfo -> Verbosity -> PackageDB -> IO ()
recache hpi verbosity packagedb =
  runProgramInvocation verbosity
    (recacheInvocation hpi verbosity packagedb)


-- | Call @hc-pkg@ to expose a package.
--
-- > hc-pkg expose [pkgid] [--user | --global | --package-db]
--
expose :: HcPkgInfo -> Verbosity -> PackageDB -> PackageId -> IO ()
expose hpi verbosity packagedb pkgid =
  runProgramInvocation verbosity
    (exposeInvocation hpi verbosity packagedb pkgid)

-- | Call @hc-pkg@ to retrieve a specific package
--
-- > hc-pkg describe [pkgid] [--user | --global | --package-db]
--
describe :: HcPkgInfo -> Verbosity -> PackageDBStack -> PackageId -> IO [InstalledPackageInfo]
describe hpi verbosity packagedb pid = do

  output <- getProgramInvocationOutput verbosity
              (describeInvocation hpi verbosity packagedb pid)
    `catchIO` \_ -> return ""

  case parsePackages output of
    Left ok -> return ok
    _       -> die' verbosity $ "failed to parse output of '"
                  ++ programId (hcPkgProgram hpi) ++ " describe " ++ display pid ++ "'"

-- | Call @hc-pkg@ to hide a package.
--
-- > hc-pkg hide [pkgid] [--user | --global | --package-db]
--
hide :: HcPkgInfo -> Verbosity -> PackageDB -> PackageId -> IO ()
hide hpi verbosity packagedb pkgid =
  runProgramInvocation verbosity
    (hideInvocation hpi verbosity packagedb pkgid)


-- | Call @hc-pkg@ to get all the details of all the packages in the given
-- package database.
--
dump :: HcPkgInfo -> Verbosity -> PackageDB -> IO [InstalledPackageInfo]
dump hpi verbosity packagedb = do

  output <- getProgramInvocationOutput verbosity
              (dumpInvocation hpi verbosity packagedb)
    `catchIO` \e -> die' verbosity $ programId (hcPkgProgram hpi) ++ " dump failed: "
                       ++ displayException e

  case parsePackages output of
    Left ok -> return ok
    _       -> die' verbosity $ "failed to parse output of '"
                  ++ programId (hcPkgProgram hpi) ++ " dump'"

parsePackages :: String -> Either [InstalledPackageInfo] [PError]
parsePackages str =
  let parsed = map parseInstalledPackageInfo' (splitPkgs str)
   in case [ msg | ParseFailed msg <- parsed ] of
        []   -> Left [   setUnitId
                       . maybe id mungePackagePaths (pkgRoot pkg)
                       $ pkg
                     | ParseOk _ pkg <- parsed ]
        msgs -> Right msgs
  where
    parseInstalledPackageInfo' =
      parseFieldsFlat fieldsInstalledPackageInfo emptyInstalledPackageInfo

--TODO: this could be a lot faster. We're doing normaliseLineEndings twice
-- and converting back and forth with lines/unlines.
splitPkgs :: String -> [String]
splitPkgs = checkEmpty . map unlines . splitWith ("---" ==) . lines
  where
    -- Handle the case of there being no packages at all.
    checkEmpty [s] | all isSpace s = []
    checkEmpty ss                  = ss

    splitWith :: (a -> Bool) -> [a] -> [[a]]
    splitWith p xs = ys : case zs of
                       []   -> []
                       _:ws -> splitWith p ws
      where (ys,zs) = break p xs

mungePackagePaths :: FilePath -> InstalledPackageInfo -> InstalledPackageInfo
-- Perform path/URL variable substitution as per the Cabal ${pkgroot} spec
-- (http://www.haskell.org/pipermail/libraries/2009-May/011772.html)
-- Paths/URLs can be relative to ${pkgroot} or ${pkgrooturl}.
-- The "pkgroot" is the directory containing the package database.
mungePackagePaths pkgroot pkginfo =
    pkginfo {
      importDirs        = mungePaths (importDirs  pkginfo),
      includeDirs       = mungePaths (includeDirs pkginfo),
      libraryDirs       = mungePaths (libraryDirs pkginfo),
      frameworkDirs     = mungePaths (frameworkDirs pkginfo),
      haddockInterfaces = mungePaths (haddockInterfaces pkginfo),
      haddockHTMLs      = mungeUrls  (haddockHTMLs pkginfo)
    }
  where
    mungePaths = map mungePath
    mungeUrls  = map mungeUrl

    mungePath p = case stripVarPrefix "${pkgroot}" p of
      Just p' -> pkgroot </> p'
      Nothing -> p

    mungeUrl p = case stripVarPrefix "${pkgrooturl}" p of
      Just p' -> toUrlPath pkgroot p'
      Nothing -> p

    toUrlPath r p = "file:///"
                 -- URLs always use posix style '/' separators:
                 ++ FilePath.Posix.joinPath (r : FilePath.splitDirectories p)

    stripVarPrefix var p =
      case splitPath p of
        (root:path') -> case stripPrefix var root of
          Just [sep] | isPathSeparator sep -> Just (joinPath path')
          _                                -> Nothing
        _                                  -> Nothing


-- Older installed package info files did not have the installedUnitId
-- field, so if it is missing then we fill it as the source package ID.
-- NB: Internal libraries not supported.
setUnitId :: InstalledPackageInfo -> InstalledPackageInfo
setUnitId pkginfo@InstalledPackageInfo {
                        installedUnitId = uid,
                        sourcePackageId = pid
                      } | unUnitId uid == ""
                    = pkginfo {
                        installedUnitId = mkLegacyUnitId pid,
                        installedComponentId_ = mkComponentId (display pid)
                      }
setUnitId pkginfo = pkginfo


-- | Call @hc-pkg@ to get the source package Id of all the packages in the
-- given package database.
--
-- This is much less information than with 'dump', but also rather quicker.
-- Note in particular that it does not include the 'UnitId', just
-- the source 'PackageId' which is not necessarily unique in any package db.
--
list :: HcPkgInfo -> Verbosity -> PackageDB
     -> IO [PackageId]
list hpi verbosity packagedb = do

  output <- getProgramInvocationOutput verbosity
              (listInvocation hpi verbosity packagedb)
    `catchIO` \_ -> die' verbosity $ programId (hcPkgProgram hpi) ++ " list failed"

  case parsePackageIds output of
    Just ok -> return ok
    _       -> die' verbosity $ "failed to parse output of '"
                  ++ programId (hcPkgProgram hpi) ++ " list'"

  where
    parsePackageIds = traverse simpleParse . words

--------------------------
-- The program invocations
--

initInvocation :: HcPkgInfo -> Verbosity -> FilePath -> ProgramInvocation
initInvocation hpi verbosity path =
    programInvocation (hcPkgProgram hpi) args
  where
    args = ["init", path]
        ++ verbosityOpts hpi verbosity

registerInvocation
  :: HcPkgInfo -> Verbosity -> PackageDBStack
  -> InstalledPackageInfo
  -> RegisterOptions
  -> ProgramInvocation
registerInvocation hpi verbosity packagedbs pkgInfo registerOptions =
    (programInvocation (hcPkgProgram hpi) (args "-")) {
      progInvokeInput         = Just (showInstalledPackageInfo pkgInfo),
      progInvokeInputEncoding = IOEncodingUTF8
    }
  where
    cmdname
      | registerAllowOverwrite registerOptions = "update"
      | registerMultiInstance  registerOptions = "update"
      | otherwise                              = "register"

    args file = [cmdname, file]
             ++ (if noPkgDbStack hpi
                   then [packageDbOpts hpi (last packagedbs)]
                   else packageDbStackOpts hpi packagedbs)
             ++ [ "--enable-multi-instance"
                | registerMultiInstance registerOptions ]
             ++ [ "--force-files"
                | registerSuppressFilesCheck registerOptions ]
             ++ verbosityOpts hpi verbosity

unregisterInvocation :: HcPkgInfo -> Verbosity -> PackageDB -> PackageId
                     -> ProgramInvocation
unregisterInvocation hpi verbosity packagedb pkgid =
  programInvocation (hcPkgProgram hpi) $
       ["unregister", packageDbOpts hpi packagedb, display pkgid]
    ++ verbosityOpts hpi verbosity


recacheInvocation :: HcPkgInfo -> Verbosity -> PackageDB
                  -> ProgramInvocation
recacheInvocation hpi verbosity packagedb =
  programInvocation (hcPkgProgram hpi) $
       ["recache", packageDbOpts hpi packagedb]
    ++ verbosityOpts hpi verbosity


exposeInvocation :: HcPkgInfo -> Verbosity -> PackageDB -> PackageId
                 -> ProgramInvocation
exposeInvocation hpi verbosity packagedb pkgid =
  programInvocation (hcPkgProgram hpi) $
       ["expose", packageDbOpts hpi packagedb, display pkgid]
    ++ verbosityOpts hpi verbosity

describeInvocation :: HcPkgInfo -> Verbosity -> PackageDBStack -> PackageId
                   -> ProgramInvocation
describeInvocation hpi verbosity packagedbs pkgid =
  programInvocation (hcPkgProgram hpi) $
       ["describe", display pkgid]
    ++ (if noPkgDbStack hpi
          then [packageDbOpts hpi (last packagedbs)]
          else packageDbStackOpts hpi packagedbs)
    ++ verbosityOpts hpi verbosity

hideInvocation :: HcPkgInfo -> Verbosity -> PackageDB -> PackageId
               -> ProgramInvocation
hideInvocation hpi verbosity packagedb pkgid =
  programInvocation (hcPkgProgram hpi) $
       ["hide", packageDbOpts hpi packagedb, display pkgid]
    ++ verbosityOpts hpi verbosity


dumpInvocation :: HcPkgInfo -> Verbosity -> PackageDB -> ProgramInvocation
dumpInvocation hpi _verbosity packagedb =
    (programInvocation (hcPkgProgram hpi) args) {
      progInvokeOutputEncoding = IOEncodingUTF8
    }
  where
    args = ["dump", packageDbOpts hpi packagedb]
        ++ verbosityOpts hpi silent
           -- We use verbosity level 'silent' because it is important that we
           -- do not contaminate the output with info/debug messages.

listInvocation :: HcPkgInfo -> Verbosity -> PackageDB -> ProgramInvocation
listInvocation hpi _verbosity packagedb =
    (programInvocation (hcPkgProgram hpi) args) {
      progInvokeOutputEncoding = IOEncodingUTF8
    }
  where
    args = ["list", "--simple-output", packageDbOpts hpi packagedb]
        ++ verbosityOpts hpi silent
           -- We use verbosity level 'silent' because it is important that we
           -- do not contaminate the output with info/debug messages.


packageDbStackOpts :: HcPkgInfo -> PackageDBStack -> [String]
packageDbStackOpts hpi dbstack = case dbstack of
  (GlobalPackageDB:UserPackageDB:dbs) -> "--global"
                                       : "--user"
                                       : map specific dbs
  (GlobalPackageDB:dbs)               -> "--global"
                                       : ("--no-user-" ++ packageDbFlag hpi)
                                       : map specific dbs
  _                                   -> ierror
  where
    specific (SpecificPackageDB db) = "--" ++ packageDbFlag hpi ++ "=" ++ db
    specific _ = ierror
    ierror :: a
    ierror     = error ("internal error: unexpected package db stack: " ++ show dbstack)

packageDbFlag :: HcPkgInfo -> String
packageDbFlag hpi
  | flagPackageConf hpi
  = "package-conf"
  | otherwise
  = "package-db"

packageDbOpts :: HcPkgInfo -> PackageDB -> String
packageDbOpts _ GlobalPackageDB        = "--global"
packageDbOpts _ UserPackageDB          = "--user"
packageDbOpts hpi (SpecificPackageDB db) = "--" ++ packageDbFlag hpi ++ "=" ++ db

verbosityOpts :: HcPkgInfo -> Verbosity -> [String]
verbosityOpts hpi v
  | noVerboseFlag hpi
                   = []
  | v >= deafening = ["-v2"]
  | v == silent    = ["-v0"]
  | otherwise      = []