{ stdenv, fetchurl, bash, unzip, glibc, openssl, gcc, mesa, freetype, xorg, alsaLib, cairo, libuuid, autoreconfHook, gcc6, ... }:

{ name, src, version, source-date, source-url, ... }:

# Build the Pharo VM
stdenv.mkDerivation rec {
  inherit name src;

  # Command line invocation name.
  # Distinct name for 64-bit builds because they only work with 64-bit images.
  cmd = if stdenv.is64bit then "pharo-spur64" else "pharo-spur";

  # Choose desired VM sources. Separate for 32-bit and 64-bit VM.
  # (Could extent to building more VM variants e.g. SpurV3, Sista, etc.)
  vm = if stdenv.is64bit then "spur64src" else "spursrc";

  # Choose target platform name in the format used by the vm.
  flavor =
    if      stdenv.isLinux && stdenv.isi686    then "linux32x86"
    else if stdenv.isLinux && stdenv.isx86_64  then "linux64x64"
    else if stdenv.isDarwin && stdenv.isi686   then "macos32x86"
    else if stdenv.isDarwin && stdenv.isx86_64 then "macos64x64"
    else abort "Unsupported platform: only Linux/Darwin x86/x64 are supported.";

  # Shared data (for the sources file)
  pharo-share = import ./share.nix { inherit stdenv fetchurl unzip; };

  # Note: -fPIC causes the VM to segfault.
  hardeningDisable = [ "format" "pic" ];

  # Regenerate the configure script.
  # Unnecessary? But the build breaks without this.
  autoreconfPhase = ''
    (cd opensmalltalk-vm/platforms/unix/config && make)
  '';

  # Configure with options modeled on the 'mvm' build script from the vm.
  configureScript = "platforms/unix/config/configure";
  configureFlags = [ "--without-npsqueak"
                     "--with-vmversion=5.0"
                     "--with-src=${vm}" ];
  CFLAGS = "-msse2 -D_GNU_SOURCE -DCOGMTVM=0 -g -O2 -DNDEBUG -DDEBUGVM=0";
  LDFLAGS = "-Wl,-z,now";

  # VM sources require some patching before build.
  prePatch = ''
    patchShebangs opensmalltalk-vm/build.${flavor}
    # Fix hard-coded path to /bin/rm in a script
    sed -i -e 's:/bin/rm:rm:' opensmalltalk-vm/platforms/unix/config/mkmf
    # Fill in mandatory metadata about the VM source version
    sed -i -e 's!\$Date\$!$Date: ${source-date} $!' \
           -e 's!\$Rev\$!$Rev: ${version} $!' \
           -e 's!\$URL\$!$URL: ${source-url} $!' \
           opensmalltalk-vm/platforms/Cross/vm/sqSCCSVersion.h
  '';

  # Note: --with-vmcfg configure option is broken so copy plugin specs to ./
  preConfigure = ''
    cd opensmalltalk-vm
    cp build.${flavor}/pharo.cog.spur/plugins.{ext,int} .
  '';

  # (No special build phase.)

  installPhase = ''
    # Install in working directory and then copy
    make install-squeak install-plugins prefix=$(pwd)/products

    # Copy binaries & rename from 'squeak' to 'pharo'
    mkdir -p $out
    cp    products/lib/squeak/5.0-*/squeak $out/pharo

    cp -r products/lib/squeak/5.0-*/*.so $out
    ln -s "${pharo-share}/lib/"*.sources $out

    # Create a shell script to run the VM in the proper environment.
    # 
    # These wrapper puts all relevant libraries into the
    # LD_LIBRARY_PATH. This is important because various C code in the VM
    # and Smalltalk code in the image will search for them there.
    mkdir -p $out/bin
    chmod u+w $out/bin

    # Note: include ELF rpath in LD_LIBRARY_PATH for finding libc.
    libs=$out:$(patchelf --print-rpath $out/pharo):${cairo}/lib:${mesa}/lib:${freetype}/lib:${openssl}/lib:${libuuid}/lib:${alsaLib}/lib:${xorg.libICE}/lib:${xorg.libSM}/lib

    # Create the script
    cat > $out/bin/${cmd} <<EOF
    #!/bin/sh
    set -f
    LD_LIBRARY_PATH="\$LD_LIBRARY_PATH:$libs" exec $out/pharo "\$@"
    EOF
    chmod +x $prefix/bin/${cmd}
  '';

  enableParallelBuilding = true;

  # Note: Force gcc6 because gcc5 crashes when compiling the VM.
  buildInputs = [ bash unzip glibc openssl gcc6 mesa freetype xorg.libX11 xorg.libICE xorg.libSM alsaLib cairo pharo-share libuuid autoreconfHook ];


  meta = {
    description = "Clean and innovative Smalltalk-inspired environment";
    longDescription = ''
      Pharo's goal is to deliver a clean, innovative, free open-source
      Smalltalk-inspired environment. By providing a stable and small core
      system, excellent dev tools, and maintained releases, Pharo is an
      attractive platform to build and deploy mission critical applications.

      This package provides the executable VM. You should probably not care
      about this package (which represents a packaging detail) and have a
      look at the pharo-vm-core package instead.

      Please fill bug reports on http://bugs.pharo.org under the 'Ubuntu
      packaging (ppa:pharo/stable)' project.
    '';
    homepage = http://pharo.org;
    license = stdenv.lib.licenses.mit;
    maintainers = [ stdenv.lib.maintainers.lukego ];
    # Pharo VM sources are packaged separately for darwin (OS X)
    platforms = with stdenv.lib;
                  intersectLists
                    platforms.mesaPlatforms
                    (subtractLists platforms.darwin platforms.unix);
  };
}