{ self, pkgs, ... }:
{
  # Only use homebrew for casks.
  homebrew.enable = true;

  nix = {
    gc = {
      automatic = true;
      interval = {
        Hour = 3;
        Minute = 15;
        Weekday = 7;
      };
      options = "--delete-older-than 30d";
    };

    optimise = {
      automatic = true;
      interval = {
        Hour = 3;
        Minute = 15;
        Weekday = 7;
      };
    };

    settings.experimental-features = "nix-command flakes";
  };

  # Enables Touch ID for sudo prompts.
  security.pam.services.sudo_local.touchIdAuth = true;

  environment = {
    variables = rec {
      XDG_CACHE_HOME = "$HOME/.cache";
      XDG_CONFIG_HOME = "$HOME/.config";
      XDG_DATA_HOME = "$HOME/.local/share";
      XDG_STATE_HOME = "$HOME/.local/state";
    };

    shellAliases = {
      l = "ls -alh";
      ll = "ls -l";
      ls = "ls --color=tty";
      ff = "clear;fastfetch";
      nb = "nix-build";
      nix-rebuild = "sudo darwin-rebuild switch";
    };

    systemPackages = with pkgs; [
      wget
      fastfetch
      btop
    ];
  };

  # Don't touch this unless needed.
  system = {
    configurationRevision = self.rev or self.dirtyRev or null;
    stateVersion = 6;
  };

  nixpkgs.hostPlatform = "aarch64-darwin";
}