{ config, pkgs, modulesPath, ... }:
{

  imports = [ "${modulesPath}/image/repart.nix" ];

  fileSystems."/".device = "/dev/disk/by-label/nixos";

  # https://nixos.org/manual/nixos/stable/#sec-image-repart
  # https://x86.lol/generic/2024/08/28/systemd-sysupdate.html
  image.repart = {
    name = "image";
    partitions = {
      "esp" = {
        # The contents to end up in the filesystem image.
        contents = {
          "/EFI/BOOT/BOOTX64.EFI".source = "${pkgs.systemd}/lib/systemd/boot/efi/systemd-bootx64.efi";
          # https://man.archlinux.org/man/loader.conf.5
          "/loader/entries/loader.conf".source = pkgs.writeText "loader.conf" ''
            timeout 0
            editor yes
            default *
            logLevel=debug
          '';
          "/loader/loader.conf".source = pkgs.writeText "loader.conf" ''
            timeout 0
            editor yes
            default *
            logLevel=debug
          '';
          # nixos-*.conf
          # "/loader/entries/nixos.conf".source = pkgs.writeText "nixos.conf" ''
          #   title NixOS
          #   linux /EFI/nixos/kernel.efi
          #   initrd /EFI/nixos/initrd.efi
          #   options init=/nix/store/.../init root=LABEL=nixos
          # '';
        };
        # https://www.man7.org/linux//man-pages/man5/repart.d.5.html
        repartConfig = {
          Priority = 1;
          Type = "esp";
          MountPoint = "/boot";
          Format = "vfat";
          UUID = "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa";
          SizeMinBytes = "500M";
          SizeMaxBytes = "500M";
        };
      };
      "root" = {
        storePaths = [ config.system.build.toplevel ];
        repartConfig = {
          Priority = 2;
          Type = "root";
          Label = "nixos";
          MountPoint = "/";
          Format = "ext4";
          UUID = "bbbbbbbb-bbbb-bbbb-bbbb-bbbbbbbbbbbb";
          # populates the fs twice
          Minimize = "guess";
          # Minimize = "off";
          # SizeMinBytes = "1G";
          # SizeMaxBytes = "20G";
        };
      };
    };
  };

  # disko.devices.disk.main = {
  #   device = "/dev/sda";
  #   type = "disk";
  #   content = {
  #     type = "gpt";
  #     partitions = {
  #       MBR = {
  #         priority = 0;
  #         size = "1M";
  #         type = "EF02";
  #       };
  #       ESP = {
  #         priority = 1;
  #         size = "500M";
  #         type = "EF00";
  #         content = {
  #           type = "filesystem";
  #           format = "vfat";
  #           mountpoint = "/boot";
  #         };
  #       };
  #       root = {
  #         priority = 2;
  #         size = "100%";
  #         content = {
  #           type = "filesystem";
  #           format = "ext4";
  #           mountpoint = "/";
  #         };
  #       };
  #     };
  #   };
  # };

}