Save custom post meta into attribute and set by default attribute term into the product - Woocommerce

Save custom post meta into attribute and set by default attribute term into the product - Woocommerce.php

<?php

/*
 * Save custom post meta into attribute and set by default attribute term into the product - Woocommerce
*/

function danea_produttore_meta($product_id)
{
	// Verifica se l'ordine è in fase di elaborazione
	if (is_checkout() && !is_wc_endpoint_url('order-received')) {
        return;
    }   
	
$taxonomy = 'pa_denominazione'; // The taxonomy
    
$term_name = get_post_meta($product_id , 'meta_easyfatt_libero_1', true); // The term "NAME" ( custom post meta )
	
//$term_slug = sanitize_title($term_name); // The term "slug"
	

// get an instance of the WC_Product Object
$product = wc_get_product( $product_id );

$attributes = (array) $product->get_attributes();

if ( !empty($term_name) ){

    $attribute = new WC_Product_Attribute();

    $attribute->set_id( sizeof( $attributes) + 1 );
    $attribute->set_name( $taxonomy );
    $attribute->set_options( array( $term_name ) );
    $attribute->set_position( sizeof( $attributes) + 1 );
    $attribute->set_visible( true );
    $attribute->set_variation( false );
    $attributes[] = $attribute;

    $product->set_attributes( $attributes );
}
	
//If calling wp_update_post, unhook this function so it doesn't loop infinitely
remove_action('woocommerce_update_product', 'danea_produttore_meta', 99, 1);
	
// Save
$product->save();
	
// re-hook this function
add_action('woocommerce_update_product', 'danea_produttore_meta', 99, 1);
	
// Append the new term in the product
if( ! has_term( $term_name, $taxonomy, $product_id ))
    wp_set_object_terms($product_id,/*$term_slug,*/ $taxonomy, true );


}
add_action('woocommerce_update_product', 'danea_produttore_meta', 99, 1);