<?php

/**

 * Sitemaps: WP_Sitemaps_Provider class

 *

 * This class is a base class for other sitemap providers to extend and contains shared functionality.

 *

 * @package WordPress

 * @subpackage Sitemaps

 * @since 5.5.0

 */

/**

 * Class WP_Sitemaps_Provider.

 *

 * @since 5.5.0

 */

abstract class WP_Sitemaps_Provider {

	/**

	 * Provider name.

	 *

	 * This will also be used as the public-facing name in URLs.

	 *

	 * @since 5.5.0

	 *

	 * @var string

	 */

	protected $name = '';

	/**

	 * Object type name (e.g. 'post', 'term', 'user').

	 *

	 * @since 5.5.0

	 *

	 * @var string

	 */

	protected $object_type = '';

	/**

	 * Gets a URL list for a sitemap.

	 *

	 * @since 5.5.0

	 *

	 * @param int    $page_num       Page of results.

	 * @param string $object_subtype Optional. Object subtype name. Default empty.

	 * @return array Array of URLs for a sitemap.

	 */

	abstract public function get_url_list( $page_num, $object_subtype = '' );

	/**

	 * Gets the max number of pages available for the object type.

	 *

	 * @since 5.5.0

	 *

	 * @param string $object_subtype Optional. Object subtype. Default empty.

	 * @return int Total number of pages.

	 */

	abstract public function get_max_num_pages( $object_subtype = '' );

	/**

	 * Gets data about each sitemap type.

	 *

	 * @since 5.5.0

	 *

	 * @return array[] Array of sitemap types including object subtype name and number of pages.

	 */

	public function get_sitemap_type_data() {

		$sitemap_data = array();

		$object_subtypes = $this->get_object_subtypes();

		// If there are no object subtypes, include a single sitemap for the

		// entire object type.

		if ( empty( $object_subtypes ) ) {

			$sitemap_data[] = array(

				'name'  => '',

				'pages' => $this->get_max_num_pages(),

			);

			return $sitemap_data;

		}

		// Otherwise, include individual sitemaps for every object subtype.

		foreach ( $object_subtypes as $object_subtype_name => $data ) {

			$object_subtype_name = (string) $object_subtype_name;

			$sitemap_data[] = array(

				'name'  => $object_subtype_name,

				'pages' => $this->get_max_num_pages( $object_subtype_name ),

			);

		}

		return $sitemap_data;

	}

	/**

	 * Lists sitemap pages exposed by this provider.

	 *

	 * The returned data is used to populate the sitemap entries of the index.

	 *

	 * @since 5.5.0

	 *

	 * @return array[] Array of sitemap entries.

	 */

	public function get_sitemap_entries() {

		$sitemaps = array();

		$sitemap_types = $this->get_sitemap_type_data();

		foreach ( $sitemap_types as $type ) {

			for ( $page = 1; $page <= $type['pages']; $page ++ ) {

				$sitemap_entry = array(

					'loc' => $this->get_sitemap_url( $type['name'], $page ),

				);

				/**

				 * Filters the sitemap entry for the sitemap index.

				 *

				 * @since 5.5.0

				 *

				 * @param array  $sitemap_entry  Sitemap entry for the post.

				 * @param string $object_type    Object empty name.

				 * @param string $object_subtype Object subtype name.

				 *                               Empty string if the object type does not support subtypes.

				 * @param int    $page           Page number of results.

				 */

				$sitemap_entry = apply_filters( 'wp_sitemaps_index_entry', $sitemap_entry, $this->object_type, $type['name'], $page );

				$sitemaps[] = $sitemap_entry;

			}

		}

		return $sitemaps;

	}

	/**

	 * Gets the URL of a sitemap entry.

	 *

	 * @since 5.5.0

	 *

	 * @global WP_Rewrite $wp_rewrite WordPress rewrite component.

	 *

	 * @param string $name The name of the sitemap.

	 * @param int    $page The page of the sitemap.

	 * @return string The composed URL for a sitemap entry.

	 */

	public function get_sitemap_url( $name, $page ) {

		global $wp_rewrite;

		// Accounts for cases where name is not included, ex: sitemaps-users-1.xml.

		$params = array_filter(

			array(

				'sitemap'         => $this->name,

				'sitemap-subtype' => $name,

				'paged'           => $page,

			)

		);

		$basename = sprintf(

			'/wp-sitemap-%1$s.xml',

			implode( '-', $params )

		);

		if ( ! $wp_rewrite->using_permalinks() ) {

			$basename = '/?' . http_build_query( $params, null, '&' );

		}

		return home_url( $basename );

	}

	/**

	 * Returns the list of supported object subtypes exposed by the provider.

	 *

	 * @since 5.5.0

	 *

	 * @return array List of object subtypes objects keyed by their name.

	 */

	public function get_object_subtypes() {

		return array();

	}

}