Toolset Relationship field

/**
 * 1. Toolset API
 */
function pm_toolset_related_posts_fields($custom_field_value, $custom_field, $post) {
    // The permastructure tag should be formated like this
    // %__{relationship_slug}%, eg. %__posts_pages%

    // Do not change native permalinks
    if($native_uri || empty($post->ID) || !function_exists('toolset_get_relationship')) { return $custom_field_value; }

    $relationship = toolset_get_relationship($custom_field);

    if(!empty($relationship)) {
        $related_post_id = toolset_get_related_post($post->ID, $custom_field);

        if(!empty($related_post_id)) {
            $related_post = get_post($related_post_id);

            if(!empty($related_post->post_name)) {
                $custom_field_value = Permalink_Manager_Helper_Functions::force_custom_slugs($related_post->post_name, $related_post);
            }
        }
    }

    return $custom_field_value;
}
add_filter('permalink_manager_custom_field_value', 'pm_toolset_related_posts_fields', 1, 5);

/**
 * 2. Legacy variant
 */
function pm_toolset_related_posts_fields($default_uri, $native_slug, $post, $slug, $native_uri) {
    global $wpdb;

    // The permastructure tag should be formated like this
    // %__{relationship_slug}%, eg. %__posts_pages%

    // Do not change native permalinks
    if($native_uri || empty($post->ID) || !function_exists('toolset_get_relationship')) { return $default_uri; }

    // Use it only when custom fields tags are present in the permastructure settings
    if(strpos($default_uri, "%__") === false) { return $default_uri; }

    // Use it only for specific post types
    // if(empty($post->post_type) && !in_array($post->post_type, array('cpt1', 'cpt2'))) { return $default_uri; }

    // List of available relationship fields that should be replaced
    $relationship_fields = $wpdb->get_col("SELECT slug FROM {$wpdb->prefix}toolset_relationships");

    if(!empty($relationship_fields)) {
        foreach($relationship_fields as $field) {
            if(strpos($default_uri, "%__{$field}%") === false) { continue; }

            $related_post_id = toolset_get_related_post($post, $field);

            if(!empty($related_post_id) && is_numeric($related_post_id)) {
                $related_post_uri = get_page_uri($related_post_id);

                $default_uri = str_replace("%__{$field}%", $related_post_uri, $default_uri);
            }
        }
    }
    return $default_uri;
}
add_filter('permalink_manager_filter_default_post_uri', 'pm_toolset_related_posts_fields', 5, 5);