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

  options = {
    _1password = {
      enable = lib.mkEnableOption {
        description = "Enable 1Password.";
        default = false;
      };
    };
  };

  config = lib.mkIf (config.gui.enable && config._1password.enable) {
    unfreePackages = [ "1password" "_1password-gui" "1password-cli" ];
    home-manager.users.${config.user} = {
      home.packages = with pkgs; [ _1password-gui ];
    };

    # https://1password.community/discussion/135462/firefox-extension-does-not-connect-to-linux-app
    # On Mac, does not apply: https://1password.community/discussion/142794/app-and-browser-integration
    # However, the button doesn't work either:
    # https://1password.community/discussion/140735/extending-support-for-trusted-web-browsers
    environment.etc."1password/custom_allowed_browsers".text = ''
      ${
        config.home-manager.users.${config.user}.programs.firefox.package
      }/Applications/Firefox.app/Contents/MacOS/firefox
      firefox
    '';
  };

}