{
  config,
  lib,
  pkgs,
  ...
}: let
  cfg = config.soispha.services.water-reminder;
in {
  options.soispha.services.water-reminder = {
    enable = lib.mkEnableOption "periodic reminder for water intake";

    frequency = lib.mkOption {
      type = lib.types.str;
      default = "*-*-* *:00/30:00"; # Every 30 minutes
      description = ''
        How often to remind. This value is passed to the systemd
        timer configuration as the `OnCalendar` option. See
        {manpage}`systemd.time(7)` for more information about the format.
      '';
    };
  };

  config = lib.mkIf cfg.enable {
    home-manager.users.soispha = {
      systemd.user.services.water-reminder = {
        Unit = {Description = "Water reminder";};
        Service = {
          CPUSchedulingPolicy = "idle";
          IOSchedulingClass = "idle";
          ExecStart = lib.getExe (
            pkgs.writeShellApplication {
              name = "water-reminder";

              inheritPath = false;
              runtimeInputs = [pkgs.libnotify];

              text =
                # bash
                ''
                  notify-send 'Seek fluid intake' 'Water intake required' --wait --expire-time=0 --urgency=critical
                '';
            }
          );
        };
      };

      systemd.user.timers.water-reminder = {
        Unit = {Description = "periodic reminder for water intake";};
        Timer = {
          Unit = "water-reminder.service";
          OnCalendar = cfg.frequency;
        };
        Install = {WantedBy = ["timers.target"];};
      };
    };
  };
}