{
  description = "PatOS is a minimal, immutable Linux distribution specialized for the Patagia Platform.";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
  };

  outputs = { self, nixpkgs }: {
    lib = {
      # Prepare a ready-to-boot disk image.
      mkInstallImage = nixos:
        let
          config = nixos.config;
          pkgs = nixpkgs.legacyPackages.x86_64-linux.pkgs;
        in
        nixos.pkgs.runCommand "update-${config.system.image.version}"
          {
            nativeBuildInputs = with pkgs; [ qemu ];
          } ''
          mkdir -p $out
          qemu-img convert -f raw -O qcow2 -C ${config.system.build.image}/${config.boot.uki.name}_${config.system.image.version}.raw $out/disk.qcow2
        '';
    };

    devShells.x86_64-linux.default =
      let
        pkgs = nixpkgs.legacyPackages.x86_64-linux;
      in
      pkgs.mkShell {
        packages = [
          self.packages.x86_64-linux.qemu-efi
        ];
      };

    packages.x86_64-linux = {
      default = self.packages.x86_64-linux.patos_image;

      patos_image = self.lib.mkInstallImage self.nixosConfigurations.patos;

      # A helper script to run the disk images above.
      qemu-efi =
        let
          pkgs = nixpkgs.legacyPackages.x86_64-linux;
        in
        pkgs.writeShellApplication {
          name = "qemu-efi";

          runtimeInputs = [ pkgs.qemu_kvm ];

          text = ''
            qemu-system-x86_64 \
              -smp 2 -m 2048 -machine q35,accel=kvm \
              -bios ${pkgs.OVMF.fd}/FV/OVMF.fd \
              -snapshot \
              -display none \
              -serial stdio "$@"
          '';
        };
    };

    nixosConfigurations = {
      patos = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        modules = [
          ./base.nix
        ];
      };
    };
  };
}