nixos-config/modules/sddm.nix

{ config, lib, pkgs, ... }:
let
  inherit (lib)
    mkEnableOption
    mkIf
  ;

  cfg = config.my.displayManager.sddm;
in
{
  options.my.displayManager.sddm.enable = mkEnableOption "SDDM setup";

  config = mkIf cfg.enable {
    services.xserver.displayManager.sddm = {
      enable = true;
      theme = "sugar-candy";
    };

    environment.systemPackages = builtins.attrValues {
      inherit (pkgs.packages)
        sddm-sugar-candy
      ;

      inherit (pkgs.libsForQt5.qt5)
        qtgraphicaleffects
        qtquickcontrols2
        qtsvg
      ;
    };
  };
}