{ lib, config, pkgs, ... }:
with lib; let
  cfg = config.local.btrfs;
in
{
  options.local.btrfs = {
    mounts = mkOption {
      default = { };

      type = with lib.types; attrsOf (submodule {
        options = {
          ssd = mkOption {
            type = bool;
          };

          device = mkOption {
            type = str;
          };

          subvol = mkOption {
            type = str;
          };
        };
      });
    };
  };

  config = mkIf (cfg.mounts != { }) {
    fileSystems =
      let
        btrfsMount = { device, subvol, ssd }: {
          inherit device;
          fsType = "btrfs";
          options = [ "noatime" "compress=zstd" "subvol=${subvol}" ] ++ optional ssd "ssd";
        };
      in
      mapAttrs (_: btrfsMount) cfg.mounts;
  };
}