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

{
  options.services.swww-randomize = {
    enable = lib.mkEnableOption "enable the randomization swww service";
    backgroundDir = lib.mkOption {
      default = config.home.homeDirectory + "/Pictures/Backgrounds";
      description = "directory with images to use for the background";
      type = with lib.types; uniq str;
    };
  };

  config = {
    services.swww.enable = true;
    systemd.user = {
      services.swww-randomize = {
        Unit = {
          Description = "randomly change the swww background image";
          Requires = "swww.service";
        };
        Service = {
          Type = "oneshot";
          ExecStart = "${lib.getExe pkgs.bash} -c '${lib.getExe pkgs.findutils} ${config.services.swww-randomize.backgroundDir} -type f | ${lib.getExe' pkgs.coreutils "shuf"} -n 1 | ${lib.getExe' pkgs.findutils "xargs"} ${lib.getExe pkgs.swww} img --transition-step 16'";
        };
        Install.WantedBy = [ "default.target" ];
      };
      timers.swww-randomize = {
        Unit.Description = "randomly changes the swww background image";
        Timer = {
          Unit = "swww-randomize";
          OnCalendar = "*-*-* *:00,30:00";
        };
        Install.WantedBy = [ "timers.target" ];
      };
    };
  };
}