<?php
/**
 * The BreadcrumbList node.
 *
 * @package ElevenRank
 * @since   1.0.0
 */

namespace ElevenRank\Modules\Schema;

defined( 'ABSPATH' ) || exit;

/**
 * Built from the same trail as the visible breadcrumb. Google asks for at least two items and an
 * address on every item except the last.
 *
 * @since 1.0.0
 */
final class Breadcrumb_Node {

	/**
	 * The node for a trail.
	 *
	 * @since 1.0.0
	 *
	 * @param Node_Context                                  $c     Page information.
	 * @param array<int, array{title: string, url: string}> $items The trail.
	 * @return array<string, mixed>|null Null when the trail is too short.
	 */
	public static function build( Node_Context $c, array $items ): ?array {
		$items = array_values(
			array_filter(
				$items,
				static function ( $item ) {
					return is_array( $item ) && '' !== trim( (string) ( $item['title'] ?? '' ) );
				}
			)
		);

		if ( count( $items ) < 2 ) {
			return null;
		}

		$elements = array();
		$last     = count( $items ) - 1;

		foreach ( $items as $index => $item ) {
			$elements[] = array(
				'@type'    => 'ListItem',
				'position' => $index + 1,
				'name'     => trim( (string) $item['title'] ),
				'item'     => $index === $last ? null : $item['url'],
			);
		}

		return array(
			'@type'           => 'BreadcrumbList',
			'@id'             => $c->id( 'breadcrumb' ),
			'itemListElement' => $elements,
		);
	}
}