{ stdenv, fetchurl, ghc, perl, ncurses, libiconv

, # If enabled, GHC will be built with the GPL-free but slower integer-simple
  # library instead of the faster but GPLed integer-gmp library.
  enableIntegerSimple ? false, gmp ? null
}:

# TODO(@Ericson2314): Cross compilation support
assert stdenv.targetPlatform == stdenv.hostPlatform;
assert !enableIntegerSimple -> gmp != null;

stdenv.mkDerivation rec {
  version = "7.2.2";
  name = "ghc-${version}";

  src = fetchurl {
    url = "http://haskell.org/ghc/dist/${version}/${name}-src.tar.bz2";
    sha256 = "0g87d3z9275dniaqzkf56qfgzp1msd89nqqhhm2gkc6iga072spz";
  };

  patches = [ ./fix-7.2.2-clang.patch ./relocation.patch ];

  buildInputs = [ ghc perl ncurses ]
                ++ stdenv.lib.optional (!enableIntegerSimple) gmp;

  buildMK = ''
    libraries/terminfo_CONFIGURE_OPTS += --configure-option=--with-curses-includes="${ncurses.dev}/include"
    libraries/terminfo_CONFIGURE_OPTS += --configure-option=--with-curses-libraries="${ncurses.out}/lib"
    ${stdenv.lib.optionalString stdenv.isDarwin ''
      libraries/base_CONFIGURE_OPTS += --configure-option=--with-iconv-includes="${libiconv}/include"
      libraries/base_CONFIGURE_OPTS += --configure-option=--with-iconv-libraries="${libiconv}/lib"
    ''}
  '' + (if enableIntegerSimple then ''
    INTEGER_LIBRARY=integer-simple
  '' else ''
    libraries/integer-gmp_CONFIGURE_OPTS += --configure-option=--with-gmp-libraries="${gmp.out}/lib"
    libraries/integer-gmp_CONFIGURE_OPTS += --configure-option=--with-gmp-includes="${gmp.dev}/include"
  '');

  preConfigure = ''
    echo "${buildMK}" > mk/build.mk
    sed -i -e 's|-isysroot /Developer/SDKs/MacOSX10.5.sdk||' configure
  '' + stdenv.lib.optionalString stdenv.isDarwin ''
    find . -name '*.hs'  | xargs sed -i -e 's|ASSERT (|ASSERT(|' -e 's|ASSERT2 (|ASSERT2(|' -e 's|WARN (|WARN(|'
    find . -name '*.lhs' | xargs sed -i -e 's|ASSERT (|ASSERT(|' -e 's|ASSERT2 (|ASSERT2(|' -e 's|WARN (|WARN(|'
    export NIX_LDFLAGS+=" -no_dtrace_dof"
  '';

  configureFlags = if stdenv.isDarwin then "--with-gcc=${./gcc-clang-wrapper.sh}"
                                      else "--with-gcc=${stdenv.cc}/bin/gcc";

  NIX_CFLAGS_COMPILE = "-fomit-frame-pointer";

  # required, because otherwise all symbols from HSffi.o are stripped, and
  # that in turn causes GHCi to abort
  stripDebugFlags=["-S" "--keep-file-symbols"];

  passthru = { targetPrefix = ""; };

  meta = {
    homepage = http://haskell.org/ghc;
    description = "The Glasgow Haskell Compiler";
    maintainers = [
      stdenv.lib.maintainers.marcweber
      stdenv.lib.maintainers.andres
      stdenv.lib.maintainers.peti
    ];
    platforms = ["x86_64-linux" "i686-linux"];  # Darwin is unsupported.
    inherit (ghc.meta) license;
    broken = true;   # broken by 51cf42ad0d3ccb55af182f1f0ee5eb5094ea5995: https://hydra.nixos.org/build/60616815
  };

}