import Distribution.PackageDescription ( PackageDescription )

import Distribution.Simple ( defaultMainWithHooks

                           , simpleUserHooks

                           , postBuild

                           , postCopy

                           , postInst

                           )

import Distribution.Simple.InstallDirs ( mandir

                                       , CopyDest (NoCopyDest)

                                       )

import Distribution.Simple.LocalBuildInfo ( LocalBuildInfo(..)

                                          , absoluteInstallDirs

                                          )

import Distribution.Simple.Utils ( installOrdinaryFiles

                                 , notice )

import Distribution.Simple.Setup ( buildVerbosity

                                 , copyDest

                                 , copyVerbosity

                                 , fromFlag

                                 , installVerbosity

                                 )

import Distribution.Verbosity ( Verbosity )

import System.IO ( openFile

                 , IOMode (WriteMode)

                 )

import System.Process ( runProcess )

import System.FilePath ( () )

-- WARNING to editors of this file:

-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

-- At this moment (Cabal 1.23), whatever you write here must be

-- compatible with ALL Cabal libraries which we support bootstrapping

-- with.  This is because pre-setup-depends versions of cabal-install will

-- build Setup.hs against the version of Cabal which MATCHES the library

-- that cabal-install was built against.  There is no way of overriding

-- this behavior without bumping the required 'cabal-version' in our

-- Cabal file.  Travis will let you know if we fail to install from

-- tarball!

main :: IO ()

main = defaultMainWithHooks $ simpleUserHooks

  { postBuild = \ _ flags _ lbi ->

      buildManpage lbi (fromFlag $ buildVerbosity flags)

  , postCopy = \ _ flags pkg lbi ->

      installManpage pkg lbi (fromFlag $ copyVerbosity flags) (fromFlag $ copyDest flags)

  , postInst = \ _ flags pkg lbi ->

      installManpage pkg lbi (fromFlag $ installVerbosity flags) NoCopyDest

  }

buildManpage :: LocalBuildInfo -> Verbosity -> IO ()

buildManpage lbi verbosity = do

  let cabal = buildDir lbi  "cabal/cabal"

      manpage = buildDir lbi  "cabal/cabal.1"

  manpageHandle <- openFile manpage WriteMode

  notice verbosity ("Generating manual page " ++ manpage ++ " ...")

  _ <- runProcess cabal ["manpage"] Nothing Nothing Nothing (Just manpageHandle) Nothing

  return ()

installManpage :: PackageDescription -> LocalBuildInfo -> Verbosity -> CopyDest -> IO ()

installManpage pkg lbi verbosity copy = do

  let destDir = mandir (absoluteInstallDirs pkg lbi copy)  "man1"

  installOrdinaryFiles verbosity destDir [(buildDir lbi  "cabal", "cabal.1")]