{
  config,
  lib,
  pkgs,
  ...
}: let
  inherit
    (lib)
    mkEnableOption
    mkOption
    mkIf
    types
    concatStrings
    mapAttrsToList
    escapeShellArg
    concatMap
    ;
  cfg = config.boot.netboot-xyz;

  grubOptions = {name, ...}: {
    options.image = mkOption {
      default = let
        url = {
          bios = {
            url = "https://github.com/netbootxyz/netboot.xyz/releases/download/2.0.79/netboot.xyz.lkrn";
            hash = "sha256-Jtu4ps9hVHYVJI1IKNnXHMD9QnFLwv53OWOaSt0yVWM=";
          };
          efi = {
            url = "https://github.com/netbootxyz/netboot.xyz/releases/download/2.0.79/netboot.xyz.efi";
            hash = "sha256-UvmoiHpThoj3cNR27KXydVfsPPSe2UDq5w/JmBDJFO8=";
          };
        };
      in
        pkgs.fetchurl ({
            curlOptsList = ["-L"];
          }
          // url.${name});
    };
  };
in {
  options.boot.netboot-xyz = {
    enable = mkEnableOption "Enable netboot.xyz in grub.";

    grub = mkOption {
      type = types.attrTag {
        bios = mkOption {
          type = types.submodule grubOptions;
        };
        efi = mkOption {
          type = types.submodule grubOptions;
        };
      };
    };
  };

  config = mkIf cfg.enable {
    boot.loader.grub.extraEntries =
      if cfg.grub ? "efi"
      then ''
        menuentry "netboot.xyz.efi" {
            chainloader @bootRoot@/netboot.xyz.efi
        }
      ''
      else if cfg.grub ? "bios"
      then ''
        menuentry "netboot.xyz.lkrn" {
            linux16 @bootRoot@/netboot.xyz.lkrn
        }
      ''
      else throw cfg.grub;

    boot.loader.grub.extraPrepareConfig = concatStrings (map (boot: let
        file =
          if cfg.grub ? "efi"
          then {
            name = "netboot.xyz.efi";
            source = "${cfg.grub.efi.image}";
          }
          else if cfg.grub ? "bios"
          then {
            name = "netboot.xyz.lkrn";
            source = "${cfg.grub.bios.image}";
          }
          else throw cfg.grub;
      in ''
        ${pkgs.coreutils}/bin/install -Dp "${file.source}" "${boot.path}/"${escapeShellArg file.name}
      '')
      config.boot.loader.grub.mirroredBoots);
  };
}