{ pkgs, lib, config, ... }: {

  options = {
    apps.flatpak.enable =
      lib.mkEnableOption "Enables flatpak support with GUI.";
  };

  config = lib.mkIf config.apps.flatpak.enable {
    # Needed for Flatpaks
    xdg.portal.enable = true;
    services.flatpak.enable = true;
    fonts.fontDir.enable = true;

    # Allow access to system fonts.
    system.fsPackages = [ pkgs.bindfs ];
    fileSystems = let
      mkRoSymBind = path: {
        device = path;
        fsType = "fuse.bindfs";
        options = [ "ro" "resolve-symlinks" "x-gvfs-hide" ];
      };
      aggregatedFonts = pkgs.buildEnv {
        name = "system-fonts";
        paths = config.fonts.packages;
        pathsToLink = [ "/share/fonts" ];
      };
    in {
      # Create an FHS mount to support flatpak host icons/fonts
      "/usr/share/icons" = mkRoSymBind (config.system.path + "/share/icons");
      "/usr/share/fonts" = mkRoSymBind (aggregatedFonts + "/share/fonts");
    };
    environment.systemPackages = with pkgs; [ gnome.gnome-software ];
  };
}