{
  config,
  lib,
  pkgs,
  ...
}: let
  cfg = config.mj.base.btrfssnapshot;
in {
  options.mj.base.btrfssnapshot = {
    enable = lib.mkEnableOption "Enable btrfs snapshots";

    subvolumes = lib.mkOption {
      default = {};
      type = with lib.types;
        attrsOf (submodule {
          options = {
            label = lib.mkOption {type = str;};
            keep = lib.mkOption {type = int;};
            refreshInterval = lib.mkOption {type = str;};
          };
        });
    };
  };

  config = lib.mkIf cfg.enable {
    systemd = {
      services =
        lib.mapAttrs'
        (
          subvolume: params:
            lib.nameValuePair
            "btrfs-snapshot-${lib.strings.sanitizeDerivationName subvolume}"
            {
              description = "${params.label} btrfs snapshot for ${subvolume} (keep ${params.keep}";
              serviceConfig.ExecStart = "${pkgs.btrfs-auto-snapshot} --verbose --label=${params.label} --keep=${params.keep} ${subvolume}";
            }
        );

      timers =
        lib.mapAttrs'
        (
          subvolume: params:
            lib.nameValuePair
            "btrfs-snapshot-${lib.strings.sanitizeDerivationName subvolume}"
            {
              description = "${params.label} btrfs snapshot for ${subvolume}";
              wantedBy = ["timers.target"];
              timerConfig.OnCalendar = params.refreshInterval;
            }
        );
    };
  };
}