Auto Complete all WooCommerce virtual orders

wc_auto_complete_virtual.php

<?php // only copy this line if needed

/**
 * Auto Complete all WooCommerce virtual orders.
 * 
 * @param  int 	$order_id The order ID to check
 * @return void
 */
function custom_woocommerce_auto_complete_virtual_orders( $order_id ) {

	// if there is no order id, exit
	if ( ! $order_id ) {
		return;
	}

	// get the order and its exit
	$order = wc_get_order( $order_id );
	$items = $order->get_items();

	// if there are no items, exit
	if ( 0 >= count( $items ) ) {
		return;
	}

	// go through each item
	foreach ( $items as $item ) {

		// if it is a variation
		if ( '0' != $item['variation_id'] ) {

			// make a product based upon variation
			$product = new WC_Product( $item['variation_id'] );

		} else {

			// else make a product off of the product id
			$product = new WC_Product( $item['product_id'] );

		}

		// if the product isn't virtual, exit
		if ( ! $product->is_virtual() ) {
			return;
		}
	}

	/*
	 * If we made it this far, then all of our items are virual
	 * We set the order to completed.
	 */
	$order->update_status( 'completed' );
}
add_action( 'woocommerce_thankyou', 'custom_woocommerce_auto_complete_virtual_orders' );