os/modules/sway/gammastep.service.nix

{pkgs, ...}: {
  Unit = {
    Description = "set color temperature of display according to time of day";
    Documentation = ["man:gammastep(1)"];
    BindsTo = ["sway-session.target"];
    After = ["sway-session.target"];
    # ConditionEnvironment requires systemd v247 to work correctly
    ConditionEnvironment = ["WAYLAND_DISPLAY"];
  };
  Service = {
    Type = "simple";
    ExecStart = "${pkgs.gammastep}/bin/gammastep -l geoclue2 -m wayland -v";
  };
  Install = {
    WantedBy = ["sway-session.target"];
  };
}