{ stdenv, lib, writeScript, buildFHSUserEnv, steam
, steam-runtime-wrapped, steam-runtime-wrapped-i686 ? null
, withJava ? false
, withPrimus ? false
, extraPkgs ? pkgs: [ ] # extra packages to add to targetPkgs
, nativeOnly ? false
, runtimeOnly ? false
}:

let
  commonTargetPkgs = pkgs: with pkgs;
    let
      tzdir = "${pkgs.tzdata}/share/zoneinfo";
      # I'm not sure if this is the best way to add things like this
      # to an FHSUserEnv
      etc-zoneinfo = pkgs.runCommand "zoneinfo" {} ''
        mkdir -p $out/etc
        ln -s ${tzdir} $out/etc/zoneinfo
        ln -s ${tzdir}/UTC $out/etc/localtime
      '';
    in [
      steamPackages.steam-fonts
      # Errors in output without those
      pciutils
      python2
      # Games' dependencies
      xlibs.xrandr
      which
      # Needed by gdialog, including in the steam-runtime
      perl
      # Open URLs
      xdg_utils
      # Zoneinfo
      etc-zoneinfo
    ] ++ lib.optional withJava jdk
      ++ lib.optional withPrimus primus
      ++ extraPkgs pkgs;

in buildFHSUserEnv rec {
  name = "steam";

  targetPkgs = pkgs: with pkgs; [
    steamPackages.steam
    # License agreement
    gnome3.zenity
  ] ++ commonTargetPkgs pkgs;

  multiPkgs = pkgs: with pkgs; [
    # These are required by steam with proper errors
    xlibs.libXcomposite
    xlibs.libXtst
    xlibs.libXrandr
    xlibs.libXext
    xlibs.libX11
    xlibs.libXfixes

    # Not formally in runtime but needed by some games
    gst_all_1.gstreamer
    gst_all_1.gst-plugins-ugly
    libdrm
    mono
    xorg.xkeyboardconfig
    xlibs.libpciaccess

    (steamPackages.steam-runtime-wrapped.override {
      inherit nativeOnly runtimeOnly;
    })
  ];

  extraBuildCommands = ''
    mkdir -p steamrt
    ln -s ../lib/steam-runtime steamrt/${steam-runtime-wrapped.arch}
    ${lib.optionalString (steam-runtime-wrapped-i686 != null) ''
      ln -s ../lib32/steam-runtime steamrt/${steam-runtime-wrapped-i686.arch}
    ''}
  '';

  extraInstallCommands = ''
    mkdir -p $out/share/applications
    ln -s ${steam}/share/icons $out/share
    ln -s ${steam}/share/pixmaps $out/share
    sed "s,/usr/bin/steam,$out/bin/steam,g" ${steam}/share/applications/steam.desktop > $out/share/applications/steam.desktop
  '';

  profile = ''
    export STEAM_RUNTIME=/steamrt
    export TZDIR=/etc/zoneinfo
  '';

  runScript = "steam";

  passthru.run = buildFHSUserEnv {
    name = "steam-run";

    targetPkgs = commonTargetPkgs;
    inherit multiPkgs extraBuildCommands;

    runScript =
      let ldPath = map (x: "/steamrt/${steam-runtime-wrapped.arch}/" + x) steam-runtime-wrapped.libs
                 ++ lib.optionals (steam-runtime-wrapped-i686 != null) (map (x: "/steamrt/${steam-runtime-wrapped-i686.arch}/" + x) steam-runtime-wrapped-i686.libs);
      in writeScript "steam-run" ''
        #!${stdenv.shell}
        run="$1"
        if [ "$run" = "" ]; then
          echo "Usage: steam-run command-to-run args..." >&2
          exit 1
        fi
        shift
        export LD_LIBRARY_PATH=${lib.concatStringsSep ":" ldPath}:$LD_LIBRARY_PATH
        exec "$run" "$@"
      '';
  };
}