{ lib, config, options, ... }:
let

  driveModule = lib.types.submodule {
    options = {
      name = lib.mkOption {
        type = lib.types.str;
        description = ''
          The path of the drive.
          Note that a / is already added at the beginning.
        '';
        default = "";
        example = "drive2";
      };
      drive = lib.mkOption {
        type = lib.types.attrsOf lib.types.anything;
        description = "The attrs of the drive";
        default = { };
        example = {
          device = "/dev/disk/by-label/DRIVE2";
          fsType = "ext4";
          options = [ "noatime" "nodiratime" "discard" ];
        };
      };
    };
  };
in {
  options.mods = {
    extraDrives = lib.mkOption {
      default = [ ];
      example = [{
        name = "drive2";
        drive = {
          device = "/dev/disk/by-label/DRIVE2";
          fsType = "ext4";
          options = [ "noatime" "nodiratime" "discard" ];
        };
      }];
      #  TODO:  how to make this work
      # type = with lib.types; listOf (attrsOf driveModule);
      type = with lib.types; listOf (attrsOf anything);
      description = ''
        Extra drives to add.
      '';
    };
  };

  config = (lib.optionalAttrs (options ? fileSystems) {
    fileSystems = builtins.listToAttrs (map ({ name, drive }: {
      name = "/" + name;
      value = drive;
    }) config.mods.extraDrives);
  });
}