<?php
declare(strict_types=1);

namespace WebCalendar\WP;

defined( 'ABSPATH' ) || exit;

/**
 * Sitemap provider for single event pages.
 *
 * Registers with WordPress's built-in sitemap system (WP 5.5+) so search
 * engines can discover event permalink pages at /webcalendar/event/{id}-{slug}/.
 * Only public-access events are included.
 */
class EventSitemapProvider extends \WP_Sitemaps_Provider {

	/**
	 * Provider name used in sitemap URLs.
	 *
	 * @var string
	 */
	protected $name = 'webcalendar';

	/**
	 * Object type for max-URL filtering.
	 *
	 * @var string
	 */
	protected $object_type = 'webcal_event';

	/**
	 * Get the list of event URLs for a sitemap page.
	 *
	 * @param int    $page_num       Page number (1-based).
	 * @param string $object_subtype Not used.
	 * @return array<int, array{loc: string, lastmod?: string}>
	 */
	public function get_url_list( $page_num, $object_subtype = '' ): array {
		if ( SingleEventPage::get_mode() === 'off' ) {
			return [];
		}

		$container  = Container::get_instance();
		$event_repo = $container->get_event_repository();

		$per_page = wp_sitemaps_get_max_urls( $this->object_type );
		$offset   = ( $page_num - 1 ) * $per_page;

		$events = $event_repo->findByAccessLevel( 'P', $per_page, $offset );

		$urls = [];
		foreach ( $events as $event ) {
			// A pending submission is never advertised, whoever is asking.
			if ( 'TENTATIVE' === $event->status() ) {
				continue;
			}

			// Skip events whose creator opted out of single event pages
			if ( SingleEventPage::creator_opted_out( $event->createdBy() ) ) {
				continue;
			}

			$slug = sanitize_title( $event->name() );
			$loc  = home_url( 'webcalendar/event/' . $event->id()->value() . '-' . $slug . '/' );

			$entry = [ 'loc' => $loc ];

			$mod_date = $event->modDate();
			if ( $mod_date !== null && $mod_date > 0 ) {
				$mod_time = $event->modTime() ?? 0;
				$date_str = sprintf( '%08d', $mod_date );
				$time_str = $mod_time > 0 ? sprintf( '%06d', $mod_time ) : '000000';

				$entry['lastmod'] = substr( $date_str, 0, 4 ) . '-'
					. substr( $date_str, 4, 2 ) . '-'
					. substr( $date_str, 6, 2 ) . 'T'
					. substr( $time_str, 0, 2 ) . ':'
					. substr( $time_str, 2, 2 ) . ':'
					. substr( $time_str, 4, 2 ) . '+00:00';
			}

			$urls[] = $entry;
		}

		return $urls;
	}

	/**
	 * Get the total number of sitemap pages for events.
	 *
	 * @param string $object_subtype Not used.
	 * @return int
	 */
	public function get_max_num_pages( $object_subtype = '' ): int {
		if ( SingleEventPage::get_mode() === 'off' ) {
			return 0;
		}

		$container  = Container::get_instance();
		$event_repo = $container->get_event_repository();

		$count    = $event_repo->countByAccessLevel( 'P' );
		$per_page = wp_sitemaps_get_max_urls( $this->object_type );

		return (int) ceil( $count / $per_page );
	}
}