{ config, lib, pkgs, extendModules, diskoLib, ... }:
let
  cfg = config.disko;

  vmVariantWithDisko = extendModules {
    modules = [
      ./lib/interactive-vm.nix
      config.disko.tests.extraConfig
    ];
  };
in
{
  imports = [ ./lib/make-disk-image.nix ];

  options.disko = {
    imageBuilder = {
      qemu = lib.mkOption {
        type = lib.types.nullOr lib.types.str;
        description = ''
          the qemu emulator string used when building disk images via make-disk-image.nix.
          Useful when using binfmt on your build host, and wanting to build disk
          images for a foreign architecture
        '';
        default = null;
        example = lib.literalExpression "\${pkgs.qemu_kvm}/bin/qemu-system-aarch64";
      };

      pkgs = lib.mkOption {
        type = lib.types.attrs;
        description = ''
          the pkgs instance used when building disk images via make-disk-image.nix.
          Useful when the config's kernel won't boot in the image-builder.
        '';
        default = pkgs;
        defaultText = lib.literalExpression "pkgs";
        example = lib.literalExpression "pkgs";
      };

      kernelPackages = lib.mkOption {
        type = lib.types.attrs;
        description = ''
          the kernel used when building disk images via make-disk-image.nix.
          Useful when the config's kernel won't boot in the image-builder.
        '';
        default = config.boot.kernelPackages;
        defaultText = lib.literalExpression "config.boot.kernelPackages";
        example = lib.literalExpression "pkgs.linuxPackages_testing";
      };

      extraRootModules = lib.mkOption {
        type = lib.types.listOf lib.types.str;
        description = ''
          extra kernel modules to pass to the vmTools.runCommand invocation in the make-disk-image.nix builder
        '';
        default = [ ];
        example = [ "bcachefs" ];
      };

      extraPostVM = lib.mkOption {
        type = lib.types.str;
        description = ''
          extra shell code to execute once the disk image(s) have been succesfully created and moved to $out
        '';
        default = "";
        example = lib.literalExpression ''
          ''${pkgs.zstd}/bin/zstd --compress $out/*raw
          rm $out/*raw
        '';
      };

      extraDependencies = lib.mkOption {
        type = lib.types.listOf lib.types.package;
        description = ''
          list of extra packages to make available in the make-disk-image.nix VM builder, an example might be f2fs-tools
        '';
        default = [ ];
      };

      name = lib.mkOption {
        type = lib.types.str;
        description = "name for the disk images";
        default = "${config.networking.hostName}-disko-images";
        defaultText = "\${config.networking.hostName}-disko-images";
      };

      copyNixStore = lib.mkOption {
        type = lib.types.bool;
        description = "whether to copy the nix store into the disk images we just created";
        default = true;
      };

      extraConfig = lib.mkOption {
        description = ''
          Extra NixOS config for your test. Can be used to specify a different luks key for tests.
          A dummy key is in /tmp/secret.key
        '';
        default = { };
      };

      imageFormat = lib.mkOption {
        type = lib.types.enum [ "raw" "qcow2" ];
        description = "QEMU image format to use for the disk images";
        default = "raw";
      };
    };

    memSize = lib.mkOption {
      type = lib.types.int;
      description = ''
        size of the memory passed to runInLinuxVM, in megabytes
      '';
      default = 1024;
    };

    devices = lib.mkOption {
      type = diskoLib.toplevel;
      default = { };
      description = "The devices to set up";
    };

    rootMountPoint = lib.mkOption {
      type = lib.types.str;
      default = "/mnt";
      description = "Where the device tree should be mounted by the mountScript";
    };

    enableConfig = lib.mkOption {
      description = ''
        configure nixos with the specified devices
        should be true if the system is booted with those devices
        should be false on an installer image etc.
      '';
      type = lib.types.bool;
      default = true;
    };

    checkScripts = lib.mkOption {
      description = ''
        Whether to run shellcheck on script outputs
      '';
      type = lib.types.bool;
      default = false;
    };

    testMode = lib.mkOption {
      internal = true;
      description = ''
        this is true if the system is being run in test mode.
        like a vm test or an interactive vm
      '';
      type = lib.types.bool;
      default = false;
    };

    tests = {
      efi = lib.mkOption {
        description = ''
          Whether efi is enabled for the `system.build.installTest`.
          We try to automatically detect efi based on the configured bootloader.
        '';
        type = lib.types.bool;
        defaultText = "config.boot.loader.systemd-boot.enable || config.boot.loader.grub.efiSupport";
        default = config.boot.loader.systemd-boot.enable || config.boot.loader.grub.efiSupport;
      };

      extraChecks = lib.mkOption {
        description = ''
          extra checks to run in the `system.build.installTest`.
        '';
        type = lib.types.lines;
        default = "";
        example = ''
          machine.succeed("test -e /var/secrets/my.secret")
        '';
      };

      extraConfig = lib.mkOption {
        description = ''
          Extra NixOS config for your test. Can be used to specify a different luks key for tests.
          A dummy key is in /tmp/secret.key
        '';
        default = { };
      };
    };
  };

  options.virtualisation.vmVariantWithDisko = lib.mkOption {
    description = ''
      Machine configuration to be added for the vm script available at `.system.build.vmWithDisko`.
    '';
    inherit (vmVariantWithDisko) type;
    default = { };
    visible = "shallow";
  };

  config = {
    _module.args.diskoLib = import ./lib {
      inherit lib;
      rootMountPoint = config.disko.rootMountPoint;
      makeTest = import (pkgs.path + "/nixos/tests/make-test-python.nix");
      eval-config = import (pkgs.path + "/nixos/lib/eval-config.nix");
    };

    system.build = (cfg.devices._scripts { inherit pkgs; checked = cfg.checkScripts; }) // (
      let
        throwIfNoDisksDetected = _: v: if cfg.devices.disk == { } then throw "No disks defined, did you forget to import your disko config?" else v;
      in
      lib.mapAttrs throwIfNoDisksDetected {
        # we keep these old outputs for compatibility
        disko = builtins.trace "the .disko output is deprecated, please use .diskoScript instead" (cfg.devices._scripts { inherit pkgs; }).diskoScript;
        diskoNoDeps = builtins.trace "the .diskoNoDeps output is deprecated, please use .diskoScriptNoDeps instead" (cfg.devices._scripts { inherit pkgs; }).diskoScriptNoDeps;

        installTest = diskoLib.testLib.makeDiskoTest {
          inherit extendModules pkgs;
          name = "${config.networking.hostName}-disko";
          disko-config = builtins.removeAttrs config [ "_module" ];
          testMode = "direct";
          efi = cfg.tests.efi;
          extraSystemConfig = cfg.tests.extraConfig;
          extraTestScript = cfg.tests.extraChecks;
        };

        vmWithDisko = lib.mkDefault config.virtualisation.vmVariantWithDisko.system.build.vmWithDisko;
      }
    );

    # we need to specify the keys here, so we don't get an infinite recursion error
    # Remember to add config keys here if they are added to types
    fileSystems = lib.mkIf cfg.enableConfig cfg.devices._config.fileSystems or { };
    boot = lib.mkIf cfg.enableConfig cfg.devices._config.boot or { };
    swapDevices = lib.mkIf cfg.enableConfig cfg.devices._config.swapDevices or [ ];
  };
}