{ lib, utils, config, pkgs, ... }: let
  inherit (lib) mkOption mkEnableOption types;
  cfg = config.bagel.services.git-gc-preserve;
  enabledServices = lib.filterAttrs (_: gcConfig: gcConfig.enable) cfg;
in
{
  options.bagel.services.git-gc-preserve = mkOption {
    default = { };
    description = "Repositories that should be garbage collected";
    type = types.attrsOf (types.submodule {
      options = {
        enable = mkEnableOption "git-gc-preserve";
        user = mkOption {
          type = types.str;
          default = "git";
          description = "The user which will run the garbage collection script";
          example = "forgejo";
        };
        group = mkOption {
          type = types.str;
          default = "git";
          description = "The group which will run the garbage collection script";
          example = "forgejo";
        };
        repoPath = mkOption {
          type = types.path;
          description = "The path to the git repository that should be garbage collected";
          example = "/var/lib/gerrit/git/nixpkgs";
        };
        timeoutSec = mkOption {
          type = types.str;
          default = "1h";
          description = "Garbage collection Systemd unit timeout";
          example = "infinity";
        };
        timerConfig = mkOption {
          type = types.attrsOf utils.systemdUtils.unitOptions.unitOption;
          default = {
            OnCalendar = "daily";
          };
          description = ''
            When to run the git-gc-preserve. See {manpage}`systemd.timer(5)` for details.
          '';
          example = {
            OnCalendar = "00:05";
            RandomizedDelaySec = "5h";
            Persistent = true;
          };
        };
      };
    });
  };
  config = {
    systemd.services =
      let
        mkGCService = name: gcConfig: {
          name = "git-gc-preserve-${name}";
          value = {
            description = "Git-GC-Preserve Service - ${name}";
            path = [ pkgs.util-linux ];
            serviceConfig = {
              WorkingDirectory = gcConfig.repoPath;
              Type = "oneshot";
              User = gcConfig.user;
              Group = gcConfig.group;
              ExecStart = lib.getExe pkgs.git-gc-preserve;
              TimeoutSec = gcConfig.timeoutSec;
            };
          };
        };
        mkServices = lib.mapAttrs' mkGCService;
      in
        mkServices enabledServices;

    systemd.timers = let
      mkGCTimer = name: gcConfig: {
        name = "git-gc-preserve-${name}";
        value = {
          wantedBy = [ "timers.target" ];
          after = [ "multi-user.target" ];
          timerConfig = gcConfig.timerConfig;
        };
      };
      mkTimer = lib.mapAttrs' mkGCTimer;
    in mkTimer enabledServices;
  };
}