Support Voxel custom fields in Permastructure formats

voxel.php

<?php
/**
 * Support Voxel custom fields in Permastructure formats
 */
function pm_new_permastructure_tag( $custom_field_value, $custom_field, $element ) {
	if ( empty( $custom_field_value ) && class_exists( '\Voxel\Post' ) && method_exists( '\Voxel\Post', 'get' ) && ! empty( $element->post_type ) ) {
		$voxel_post = \Voxel\Post::get( $element );

		if ( method_exists( $voxel_post, 'get_field' ) ) {
			$field = $voxel_post->get_field( $custom_field );

			if ( ! empty( $field ) && method_exists( $field, 'get_value_from_post' ) ) {
				$rel_posts = $field->get_value_from_post();

				if ( ( is_array( $rel_posts ) ) ) {
					if ( ! empty( $rel_posts[0] ) && is_numeric( $rel_posts[0] ) ) {
						$rel_posts = get_posts( array( 'include' => $rel_posts, 'post_type' => 'any' ) );
					}

					// Get lowest element
					if ( ! is_wp_error( $rel_posts ) && ! empty( $rel_posts ) && is_object( $rel_posts[0] ) ) {
						$rel_post = Permalink_Manager_Helper_Functions::get_lowest_element( $rel_posts[0], $rel_posts );
					}
				}

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

			}
		}
	}

	return $custom_field_value;
}
add_filter( 'permalink_manager_custom_field_value', 'pm_new_permastructure_tag', 3, 3 );