onfirm redirect.
	 * @return array{0: string, 1: string}|null
	 */
	private function result_notice( string $code ): ?array {
		switch ( $code ) {
			case 'sent':
				return array( __( 'A confirmation link has been sent to your email address. Please check your inbox.', 'woocommerce' ), 'success' );
			case 'throttled':
				return array( __( 'A confirmation link was sent recently. Please check your inbox, or wait a moment before requesting a new one.', 'woocommerce' ), 'notice' );
			case 'confirmed':
				return array( __( 'Your email address has been confirmed.', 'woocommerce' ), 'success' );
			case 'expired':
				return array( __( 'This confirmation link is invalid or has expired. Please request a new one.', 'woocommerce' ), 'error' );
			case 'mismatch':
				return array( __( 'Unable to confirm this email while you are logged in to a different account. Please log out and open the link again.', 'woocommerce' ), 'error' );
			case 'invalid':
				return array( __( 'Invalid request. Please try again.', 'woocommerce' ), 'error' );
			default:
				return null;
		}
	}

	/**
	 * Redirect to the orders section carrying a one-off result code, then exit.
	 *
	 * @param string $code Result code understood by {@see self::result_notice()}.
	 * @return never
	 */
	private function redirect_with_result( string $code ): void {
		wp_safe_redirect( add_query_arg( self::NOTICE_PARAM, $code, wc_get_account_endpoint_url( 'orders' ) ) );
		exit;
	}

	/**
	 * Validate a key and verify the user.
	 *
	 * @since 11.0.0
	 *
	 * @param int    $user_id User ID.
	 * @param string $key     Plaintext verification key.
	 * @return bool True when verification succeeded.
	 */
	public function process_verification( int $user_id, string $key ): bool {
		if ( ! $user_id || '' === $key ) {
			return false;
		}
		if ( ! $this->service->check_verification_key( $user_id, $key ) ) {
			return false;
		}
		$this->service->mark_verified( $user_id );
		return true;
	}

	/**
	 * Send (or resend) a verification email to a user.
	 *
	 * @since 11.0.0
	 *
	 * @param int $user_id User ID.
	 */
	public function send_verification_email( int $user_id ): void {
		$user = get_user_by( 'id', $user_id );
		if ( ! $user ) {
			return;
		}

		$verify_url = $this->service->build_verification_url( $user_id );

		WC()->mailer();

		/**
		 * Triggers sending of the customer email-verification email.
		 *
		 * @param int    $user_id    The WordPress user ID of the customer.
		 * @param string $verify_url The one-time verification URL to include in the email.
		 *
		 * @since 11.0.0
		 */
		do_action( 'woocommerce_customer_verify_email_notification', $user_id, $verify_url );
	}
}