WC Auto Restore Stock

wc-auto-restore-stock.php

add_action( 'woocommerce_order_status_processing_to_cancelled', 'restore_order_stock', 10, 1 );
add_action( 'woocommerce_order_status_completed_to_cancelled', 'restore_order_stock', 10, 1 );
add_action( 'woocommerce_order_status_on-hold_to_cancelled', 'restore_order_stock', 10, 1 );
add_action( 'woocommerce_order_status_processing_to_refunded', 'restore_order_stock', 10, 1 );
add_action( 'woocommerce_order_status_completed_to_refunded', 'restore_order_stock', 10, 1 );
add_action( 'woocommerce_order_status_on-hold_to_refunded', 'restore_order_stock', 10, 1 );

function restore_order_stock( $order_id ) {
	$order = new WC_Order( $order_id );

	if ( ! get_option('woocommerce_manage_stock') == 'yes' && ! sizeof( $order->get_items() ) > 0 ) {
		return;
	}

	foreach ( $order->get_items() as $item ) {

		if ( $item['product_id'] > 0 ) {
			$_product = $order->get_product_from_item( $item );

			if ( $_product && $_product->exists() && $_product->managing_stock() ) {

				    $old_stock = $_product->stock;

				    $qty = apply_filters( 'woocommerce_order_item_quantity', $item['qty'], $this, $item );

				    $new_quantity = $_product->increase_stock( $qty );

				    do_action( 'woocommerce_auto_stock_restored', $_product, $item );

				    $order->add_order_note( sprintf( __( 'Item #%s stock incremented from %s to %s.', 'woocommerce' ), $item['product_id'], $old_stock, $new_quantity) );

				    $order->send_stock_notifications( $_product, $new_quantity, $item['qty'] );
			}
  	}
  }
} // End restore_order_stock()