Noptin_WooCommerce::get_total_spent( $customer_id_or_email )

	public function get_total_spent( $customer_id_or_email ) {

		if ( empty( $customer_id_or_email ) ) {
			return 0;
		}

		if ( is_numeric( $customer_id_or_email ) ) {
			return (float) wc_get_customer_total_spent( $customer_id_or_email );
		}

		// Fetch all customer orders.
		$orders = wc_get_orders(
			array(
				'limit'         => -1,
				'billing_email' => $customer_id_or_email,
				'status'        => wc_get_is_paid_statuses(),
			)
		);

		$total = 0;

		// Get the sum of order totals.
		foreach( $orders as $order ) {
			$total += $order->get_total();
		}

		return $total;

	}