configuration.nix/home/sway/swayidle.nix

{ pkgs, ... }: {
  services.swayidle.enable = true;
  services.swayidle.events = [
    {
      event = "before-sleep";
      command = "${pkgs.swaylock}/bin/swaylock -f -i /tmp/lockpaper.jpg";
    }
  ];
  services.swayidle.timeouts = [
    {
      timeout = 600;
      command = "${pkgs.swaylock}/bin/swaylock -f -i /tmp/lockpaper.jpg";
    }
  ];
}