<?php

/**

 * Sitemaps: WP_Sitemaps class

 *

 * This is the main class integrating all other classes.

 *

 * @package WordPress

 * @subpackage Sitemaps

 * @since 5.5.0

 */

/**

 * Class WP_Sitemaps.

 *

 * @since 5.5.0

 */

class WP_Sitemaps {

	/**

	 * The main index of supported sitemaps.

	 *

	 * @since 5.5.0

	 *

	 * @var WP_Sitemaps_Index

	 */

	public $index;

	/**

	 * The main registry of supported sitemaps.

	 *

	 * @since 5.5.0

	 *

	 * @var WP_Sitemaps_Registry

	 */

	public $registry;

	/**

	 * An instance of the renderer class.

	 *

	 * @since 5.5.0

	 *

	 * @var WP_Sitemaps_Renderer

	 */

	public $renderer;

	/**

	 * WP_Sitemaps constructor.

	 *

	 * @since 5.5.0

	 */

	public function __construct() {

		$this->registry = new WP_Sitemaps_Registry();

		$this->renderer = new WP_Sitemaps_Renderer();

		$this->index    = new WP_Sitemaps_Index( $this->registry );

	}

	/**

	 * Initiates all sitemap functionality.

	 *

	 * If sitemaps are disabled, only the rewrite rules will be registered

	 * by this method, in order to properly send 404s.

	 *

	 * @since 5.5.0

	 */

	public function init() {

		// These will all fire on the init hook.

		$this->register_rewrites();

		add_action( 'template_redirect', array( $this, 'render_sitemaps' ) );

		if ( ! $this->sitemaps_enabled() ) {

			return;

		}

		$this->register_sitemaps();

		// Add additional action callbacks.

		add_filter( 'pre_handle_404', array( $this, 'redirect_sitemapxml' ), 10, 2 );

		add_filter( 'robots_txt', array( $this, 'add_robots' ), 0, 2 );

	}

	/**

	 * Determines whether sitemaps are enabled or not.

	 *

	 * @since 5.5.0

	 *

	 * @return bool Whether sitemaps are enabled.

	 */

	public function sitemaps_enabled() {

		$is_enabled = (bool) get_option( 'blog_public' );

		/**

		 * Filters whether XML Sitemaps are enabled or not.

		 *

		 * When XML Sitemaps are disabled via this filter, rewrite rules are still

		 * in place to ensure a 404 is returned.

		 *

		 * @see WP_Sitemaps::register_rewrites()

		 *

		 * @since 5.5.0

		 *

		 * @param bool $is_enabled Whether XML Sitemaps are enabled or not. Defaults

		 * to true for public sites.

		 */

		return (bool) apply_filters( 'wp_sitemaps_enabled', $is_enabled );

	}

	/**

	 * Registers and sets up the functionality for all supported sitemaps.

	 *

	 * @since 5.5.0

	 */

	public function register_sitemaps() {

		$providers = array(

			'posts'      => new WP_Sitemaps_Posts(),

			'taxonomies' => new WP_Sitemaps_Taxonomies(),

			'users'      => new WP_Sitemaps_Users(),

		);

		/* @var WP_Sitemaps_Provider $provider */

		foreach ( $providers as $name => $provider ) {

			$this->registry->add_provider( $name, $provider );

		}

	}

	/**

	 * Registers sitemap rewrite tags and routing rules.

	 *

	 * @since 5.5.0

	 */

	public function register_rewrites() {

		// Add rewrite tags.

		add_rewrite_tag( '%sitemap%', '([^?]+)' );

		add_rewrite_tag( '%sitemap-subtype%', '([^?]+)' );

		// Register index route.

		add_rewrite_rule( '^wp-sitemap\.xml$', 'index.php?sitemap=index', 'top' );

		// Register rewrites for the XSL stylesheet.

		add_rewrite_tag( '%sitemap-stylesheet%', '([^?]+)' );

		add_rewrite_rule( '^wp-sitemap\.xsl$', 'index.php?sitemap-stylesheet=sitemap', 'top' );

		add_rewrite_rule( '^wp-sitemap-index\.xsl$', 'index.php?sitemap-stylesheet=index', 'top' );

		// Register routes for providers.

		add_rewrite_rule(

			'^wp-sitemap-([a-z]+?)-([a-z\d_-]+?)-(\d+?)\.xml$',

			'index.php?sitemap=$matches[1]&sitemap-subtype=$matches[2]&paged=$matches[3]',

			'top'

		);

		add_rewrite_rule(

			'^wp-sitemap-([a-z]+?)-(\d+?)\.xml$',

			'index.php?sitemap=$matches[1]&paged=$matches[2]',

			'top'

		);

	}

	/**

	 * Renders sitemap templates based on rewrite rules.

	 *

	 * @since 5.5.0

	 *

	 * @global WP_Query $wp_query WordPress Query object.

	 */

	public function render_sitemaps() {

		global $wp_query;

		$sitemap         = sanitize_text_field( get_query_var( 'sitemap' ) );

		$object_subtype  = sanitize_text_field( get_query_var( 'sitemap-subtype' ) );

		$stylesheet_type = sanitize_text_field( get_query_var( 'sitemap-stylesheet' ) );

		$paged           = absint( get_query_var( 'paged' ) );

		// Bail early if this isn't a sitemap or stylesheet route.

		if ( ! ( $sitemap || $stylesheet_type ) ) {

			return;

		}

		if ( ! $this->sitemaps_enabled() ) {

			$wp_query->set_404();

			status_header( 404 );

			return;

		}

		// Render stylesheet if this is stylesheet route.

		if ( $stylesheet_type ) {

			$stylesheet = new WP_Sitemaps_Stylesheet();

			$stylesheet->render_stylesheet( $stylesheet_type );

			exit;

		}

		// Render the index.

		if ( 'index' === $sitemap ) {

			$sitemap_list = $this->index->get_sitemap_list();

			$this->renderer->render_index( $sitemap_list );

			exit;

		}

		$provider = $this->registry->get_provider( $sitemap );

		if ( ! $provider ) {

			return;

		}

		if ( empty( $paged ) ) {

			$paged = 1;

		}

		$url_list = $provider->get_url_list( $paged, $object_subtype );

		// Force a 404 and bail early if no URLs are present.

		if ( empty( $url_list ) ) {

			$wp_query->set_404();

			status_header( 404 );

			return;

		}

		$this->renderer->render_sitemap( $url_list );

		exit;

	}

	/**

	 * Redirects a URL to the wp-sitemap.xml

	 *

	 * @since 5.5.0

	 *

	 * @param bool     $bypass Pass-through of the pre_handle_404 filter value.

	 * @param WP_Query $query  The WP_Query object.

	 * @return bool Bypass value.

	 */

	public function redirect_sitemapxml( $bypass, $query ) {

		// If a plugin has already utilized the pre_handle_404 function, return without action to avoid conflicts.

		if ( $bypass ) {

			return $bypass;

		}

		// 'pagename' is for most permalink types, name is for when the %postname% is used as a top-level field.

		if ( 'sitemap-xml' === $query->get( 'pagename' )

			|| 'sitemap-xml' === $query->get( 'name' )

		) {

			wp_safe_redirect( $this->index->get_index_url() );

			exit();

		}

		return $bypass;

	}

	/**

	 * Adds the sitemap index to robots.txt.

	 *

	 * @since 5.5.0

	 *

	 * @param string $output robots.txt output.

	 * @param bool   $public Whether the site is public.

	 * @return string The robots.txt output.

	 */

	public function add_robots( $output, $public ) {

		if ( $public ) {

			$output .= "\nSitemap: " . esc_url( $this->index->get_index_url() ) . "\n";

		}

		return $output;

	}

}