flake/nixos/profiles/core/nix.nix

{
  lib,
  config,
  inputs,
  ...
}: {
  nix.settings = {
    substituters =
      (lib.optionals (config.time.timeZone == "Asia/Shanghai") [
        "https://mirrors.tuna.tsinghua.edu.cn/nix-channels/store" # TUNA - 清华大学 Mirror
      ])
      ++ [
        "https://nix-community.cachix.org"
        "https://guanran928.cachix.org"
      ];
    trusted-public-keys = [
      "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
      "guanran928.cachix.org-1:BE/iBCj2/pqJXG908wHRrcaV0B2fC+KbFjHsXY6b91c="
    ];

    experimental-features = [
      "auto-allocate-uids"
      "cgroups"
      "flakes"
      "nix-command"
      "no-url-literals"
    ];
    flake-registry = "";
    trusted-users = ["@wheel"];
    allow-import-from-derivation = false;
    auto-allocate-uids = true;
    auto-optimise-store = true;
    builders-use-substitutes = true;
    use-cgroups = true;
    use-xdg-base-directories = true;
  };

  nix = {
    # Add each flake input as a registry
    # To make nix3 commands consistent with the flake
    registry = lib.mapAttrs (_: value: {flake = value;}) inputs;

    # Disable nix-channel
    channel.enable = false;

    gc = {
      automatic = true;
      dates = "weekly";
      options = "--delete-older-than 7d";
    };

    extraOptions = "!include ${config.sops.secrets.nix-access-tokens.path}";
  };

  users.groups."nix-access-tokens" = {};
  sops.secrets."nix-access-tokens" = {
    group = config.users.groups."nix-access-tokens".name;
    mode = "0440";
  };
}