{
  lib,
  inputs,
  self,
  root,
}:
let
  specialArgs = {
    inherit
      inputs
      self
      util
      ;
    registry = registry.collected;
  };

  util = import ./util.nix { inherit lib; };

  registry = import ./registry.nix {
    inherit lib util;
    hosts = self.nixosConfigurations;
    root = root + "/registry";
  };

  # TODO: Refactor guest-module composition.
  guestModules = import ./guests.nix {
    inherit
      inputs
      registry
      specialArgs
      util
      ;
    repositoryModules = modules;
    root = root + "/guests";
  };
  modules.imports = [
    {
      nixpkgs.overlays = [ self.overlays.custom ];
    }
  ]
  ++ util.collectNixFiles (root + "/modules");

in
import ./hosts.nix {
  inherit
    inputs
    lib
    specialArgs
    guestModules
    ;
  registryModule = registry.module;
  repositoryModules = modules;
  root = root + "/hosts";
}