{ config, lib, pkgs, flakeRoot, ... }:

let
  packagesConfPath = "${flakeRoot}/assets/system/apps/packages.conf";
  raw = builtins.readFile packagesConfPath;

  # Split lines safely, keep guard against splitting into characters
  rawLines = lib.splitString "\n" raw;
  _guard =
    assert !(builtins.stringLength raw > 1 && builtins.length rawLines == builtins.stringLength raw);
    true;

  # Clean each line: remove CRs, remove comments, trim
  cleanLine = line:
    let
      noCR = lib.replaceStrings [ "\r" ] [ "" ] line;
      noInlineComment = lib.head (lib.splitString "#" noCR);
    in
      lib.strings.trim noInlineComment;

  # Filter out empty lines
  entries = builtins.filter (l: l != "") (map cleanLine rawLines);

  # Resolve attribute path in pkgs
  resolvePkg = name:
    let
      parts = lib.splitString "." name;
      found = lib.attrByPath parts null pkgs;
    in
      if found == null then
        throw ''
          packages.nix: package not found in pkgs
          Token          : ${builtins.toJSON name}
          packages.conf  : ${packagesConfPath}
          Hint           : check the attribute name on search.nixos.org/packages
        ''
      else
        found;

  # Final system-wide package list
  packages = builtins.seq _guard (map resolvePkg entries);

in
{

  nixpkgs.config = { allowUnfree = true; };
  environment.systemPackages = packages;
}