{ config, pkgs, lib, inputs, modulesPath, ... }:
# prior art:
# https://github.com/NixOS/nixos-hardware/blob/master/starfive/visionfive/v2/sd-image.nix
# https://github.com/nix-community/nixos-generators/blob/master/formats/raw.nix
# https://github.com/nix-community/nixos-generators/blob/master/formats/raw-efi.nix

let
  firmware = pkgs.callPackage "${inputs.nixos-hardware}/starfive/visionfive/v2/firmware.nix" { };
in {

  options.efiImage = {
    imageBaseName = lib.mkOption {
      default = "nixos-efi-image";
      description = lib.mdDoc "Prefix of the name of the generated image file.";
    };
  };

  config = {
    boot.loader.grub.device = config.fileSystems.${config.boot.loader.efi.efiSysMountPoint}.device; # hack for installBootLoader
    fileSystems.${config.boot.loader.efi.efiSysMountPoint}.neededForBoot = true;
    fileSystems."/".autoResize = true;
    boot.growPartition = true;

    #boot.loader.grub.device = "nodev";
    #boot.loader.grub.efiSupport = true;
    #boot.loader.grub.efiInstallAsRemovable = true;

    system.build.efiImage = import "${modulesPath}/../lib/make-disk-image.nix" {
      inherit config lib pkgs;
      name = "${config.efiImage.imageBaseName}-${config.system.nixos.label}-${pkgs.stdenv.hostPlatform.system}-starfive-visionfive2.img";
      #diskSize = 8*1024; # megabytes, defaults to "auto"
      bootSize = "512M"; # nixos-install default

      partitionTableType = "efi";
      installBootLoader = true;
      touchEFIVars = true;

      #efiFirmware
      #efiVariables

      fsType = config.fileSystems."/".fsType;
      # TODO: zstd
      format = "raw"; # one of qcow2, qcow2-compressed, vdi, vpc, raw.

      # TODO: make this thing able to rebuild
      #configFile = pkgs.writeText "configuration.nix" ''
      #  {
      #    imports = [ <./machine-config.nix> ];
      #  }
      #'';
    };

    assertions = [
      {
        assertion = config.boot.loader.systemd-boot.enable;
        message = "Building EFI Image requires systemd-boot";
      }
    ];
  };

}