{ enableMultiThreading ? false
, enableG3toG4         ? false
, enableInventor       ? false
, enableGDML           ? false
, enableQT             ? false
, enableXM             ? false
, enableOpenGLX11      ? false
, enableRaytracerX11   ? false

# Standard build environment with cmake.
, stdenv, fetchurl, cmake

# Optional system packages, otherwise internal GEANT4 packages are used.
, clhep ? null
, expat ? null
, zlib  ? null

# For enableGDML.
, xercesc ? null

# For enableQT.
, qt ? null # qt4SDK or qt5SDK

# For enableXM.
, motif ? null # motif or lesstif

# For enableQT, enableXM, enableOpenGLX11, enableRaytracerX11.
, mesa   ? null
, xlibsWrapper    ? null
, libXmu ? null
}:

# G4persistency library with support for GDML
assert enableGDML -> xercesc != null;

# If enableQT, Qt4/5 User Interface and Visualization drivers.
assert enableQT -> qt != null;

# Motif User Interface and Visualisation drivers.
assert enableXM -> motif != null;

# OpenGL/X11 User Interface and Visualisation drivers.
assert enableQT || enableXM || enableOpenGLX11 || enableRaytracerX11 -> mesa   != null;
assert enableQT || enableXM || enableOpenGLX11 || enableRaytracerX11 -> xlibsWrapper    != null;
assert enableQT || enableXM || enableOpenGLX11 || enableRaytracerX11 -> libXmu != null;

let
  buildGeant4 =
    { version, src, multiThreadingCapable ? false }:

    stdenv.mkDerivation rec {
      inherit version src;
      name = "geant4-${version}";

      # The data directory holds not just interaction cross section data, but other
      # files which the installer needs to write, so we link to the previously installed
      # data instead. This assumes the default data installation location of $out/share.
      preConfigure = ''
        mkdir -p $out/share/Geant4-${version}
        ln -s ${g4data}/Geant4-${version}/data $out/share/Geant4-${version}/data
      '';

      multiThreadingFlag = if multiThreadingCapable then "-DGEANT4_BUILD_MULTITHREADED=${if enableMultiThreading then "ON" else "OFF"}" else "";

      cmakeFlags = ''
        ${multiThreadingFlag}
        -DGEANT4_USE_GDML=${if enableGDML then "ON" else "OFF"}
        -DGEANT4_USE_G3TOG4=${if enableG3toG4 then "ON" else "OFF"}
        -DGEANT4_USE_QT=${if enableQT then "ON" else "OFF"}
        -DGEANT4_USE_XM=${if enableXM then "ON" else "OFF"}
        -DGEANT4_USE_OPENGL_X11=${if enableOpenGLX11 then "ON" else "OFF"}
        -DGEANT4_USE_INVENTOR=${if enableInventor then "ON" else "OFF"}
        -DGEANT4_USE_RAYTRACER_X11=${if enableRaytracerX11 then "ON" else "OFF"}
        -DGEANT4_USE_SYSTEM_CLHEP=${if clhep != null then "ON" else "OFF"}
        -DGEANT4_USE_SYSTEM_EXPAT=${if expat != null then "ON" else "OFF"}
        -DGEANT4_USE_SYSTEM_ZLIB=${if zlib != null then "ON" else "OFF"}
      '';

      g4data = installData {
        inherit version src;
      };

      enableParallelBuilding = true;
      buildInputs = [ cmake clhep expat zlib xercesc qt motif mesa xlibsWrapper libXmu ];
      propagatedBuildInputs = [ g4data clhep expat zlib xercesc qt motif mesa xlibsWrapper libXmu ];

      setupHook = ./setup-hook.sh;

      # Set the myriad of envars required by Geant4 if we use a nix-shell.
      shellHook = ''
        source $out/nix-support/setup-hook
      '';

      meta = {
        description = "A toolkit for the simulation of the passage of particles through matter";
        longDescription = ''
          Geant4 is a toolkit for the simulation of the passage of particles through matter.
          Its areas of application include high energy, nuclear and accelerator physics, as well as studies in medical and space science.
          The two main reference papers for Geant4 are published in Nuclear Instruments and Methods in Physics Research A 506 (2003) 250-303, and IEEE Transactions on Nuclear Science 53 No. 1 (2006) 270-278.
        '';
        homepage = http://www.geant4.org;
        license = stdenv.lib.licenses.g4sl;
        maintainers = [ ];
        platforms = stdenv.lib.platforms.all;
      };
    };

  installData = 
    { version, src }:
 
    stdenv.mkDerivation rec {
      inherit version src;
      name = "g4data-${version}";

      cmakeFlags = ''
        -DGEANT4_INSTALL_DATA="ON"
      '';

      buildInputs = [ cmake expat ];

      enableParallelBuilding = true;
      buildPhase = ''
        make G4EMLOW G4NDL G4NEUTRONXS G4PII G4SAIDDATA PhotonEvaporation RadioactiveDecay RealSurface
      '';

      installPhase = ''
        mkdir -p $out/Geant4-${version}
        cp -R data/ $out/Geant4-${version}
      '';

      meta = {
        description = "Data files for the Geant4 toolkit";
        homepage = http://www.geant4.org;
        license = stdenv.lib.licenses.g4sl;
        maintainers = [ ];
        platforms = stdenv.lib.platforms.all;
      };
    }; 

  fetchGeant4 = import ./fetch.nix {
    inherit stdenv fetchurl;
  };

in {
  v10_0_2 = buildGeant4 {
    inherit (fetchGeant4.v10_0_2) version src;
    multiThreadingCapable = true;
  };
}