nixconfigs/common/nix-settings.nix

# needs to be kept compatible to both NixOS and nix-darwin
{
  config,
  pkgs,
  lib,
  ...
}:

let
  inputs = config.inputInjection.flake-inputs;
  unstable = inputs.nixos-unstable;
in
{
  nix = {
    # expose all flake inputs through nix Path and registry
    registry = (lib.mapAttrs (_: value: { flake = value; }) inputs) // {
      nixpkgs.flake = inputs.nixpkgs;
    };
    nixPath = lib.mapAttrsToList (key: value: "${key}=${value.to.path}") config.nix.registry;
  };
  nix.settings = builtins.mapAttrs (_: lib.mkDefault) {
    # keep around all inputs necessary for offline-rebuilding the system
    keep-outputs = true;
    keep-derivations = true;
    trusted-users = [ "spiollinux" ];
    experimental-features = [
      "nix-command"
      "flakes"
    ];
    # use all cores for building
    cores = 0;
  };
  # TODO: manage access token with sops instead of manual deployment
  # permissions: needs to be readable by the user invoking nix and root (for nix daemon)
  nix.extraOptions = ''
    !include /etc/nix/secrets.conf
  '';
}