Auto update product custom field based on stock not working

• jcmatoskx

• October 20, 2020 at 2:25 am

I have an ACF field “DeliverySpeed” attached to Products with the values ‘Fast’ and ‘Slow’

I am trying to update this field to change to value ‘Slow’ automatically every time the product stock is zero or less (product on backorder)

I have managed to come up to this code so far however it is not working and I can’t find out what seems to be the issue:

add_action( 'woocommerce_payment_complete', 'update_product_custom_field_after_reduced_stock_levels', 20, 2 );
add_action( 'woocommerce_order_status_completed', 'update_product_custom_field_after_reduced_stock_levels', 20, 2 );
add_action( 'woocommerce_order_status_processing', 'update_product_custom_field_after_reduced_stock_levels', 20, 2 );
add_action( 'woocommerce_order_status_on-hold', 'update_product_custom_field_after_reduced_stock_levels', 20, 2 );
function update_product_custom_field_( $order_id, $order = '' ) {
    // Continue only when order has reduced product stock levels
    if ( wc_string_to_bool( get_post_meta( $order_id, '_order_stock_reduced', true ) ) )
        return $order_id; // Exit
    
    if( ! $order || ! is_a( $order, 'WC_Order') ) {
        $order = wc_get_order( $order_id ); // Get the WC_Order object if it's empty
    }
    
    $field_key = 'DeliverySpeed';
        
    // Loop through order items
    foreach ( $order->get_items() as $item ) {
        $product     = $cart_item['data'];
        $product_id  = $product->get_id();
        $stock_qty   = $product->get_stock_quantity();
        $field_value = get_field( $field_key, $product_id ); // Get ACF field value
        
        if ( $stock_qty <= 0 && $field_value === 'Fast' ) {
            update_field( $field_key, 'Slow', $product_id );
        }
        elseif ( $stock_qty > 0 && $field_value === 'Slow' ) {
            update_field( $field_key, 'Fast', $product_id );
        }
    }
}

Thank you in advance for the attention and advice.