{ lib, config, pkgs, flakeRoot, import-tree, home-manager, ... }:

let
  hostname = "traveldroid";

  modulesPath = "${flakeRoot}/generated/modules/${hostname}";
  usersPath   = "${flakeRoot}/generated/users";

  # Import raw modules (might be functions)
  hostModulesRaw = import-tree modulesPath;
  globalUsersRaw = import-tree usersPath;

  # Helper to fully evaluate import-tree nodes into module sets
  evalModule = m:
    if lib.isFunction m then
      m { lib = lib; pkgs = pkgs; config = config; flakeRoot = flakeRoot; home-manager = home-manager; }
    else
      m;

  # Evaluate all modules into sets
  hostModules = lib.mapAttrsToList (_: mod: evalModule mod) hostModulesRaw;
  globalUsers = lib.mapAttrsToList (_: mod: evalModule mod) globalUsersRaw;

  # Merge all evaluated modules
  allModules = hostModules ++ globalUsers;

  # Merge all _module.args.hmUsers
  allHmUsers = lib.foldl' (acc: m:
    let
      hmUsers = if (builtins.hasAttr "_module" m) &&
                   (builtins.hasAttr "args" m._module) &&
                   (builtins.hasAttr "hmUsers" m._module.args)
                then m._module.args.hmUsers
                else {};
    in acc // hmUsers
  ) {} allModules;

in
{
  #################################
  # Core system config
  #################################

  networking.hostName = hostname;
  system.stateVersion = "26.05";

  #################################
  # Imports
  #################################

  imports =
    [
      ./boot.nix
      ./hardware-configuration.nix
      home-manager.nixosModules.home-manager
    ]
    ++ allModules;

  #################################
  # Home Manager integration
  #################################

  home-manager.useGlobalPkgs = true;
  home-manager.useUserPackages = true;

  # Inject the merged users directly under Home Manager
  home-manager.users = allHmUsers;

  #################################
  # Example: system packages
  #################################
  environment.systemPackages = [
    pkgs.dconf
  ];

  programs.dconf.enable = true;
}