<?php
/**
 * Sitemaps: WP_Sitemaps_Taxonomies class
 *
 * Builds the sitemaps for the 'taxonomy' object type.
 *
 * @package WordPress
 * @subpackage Sitemaps
 * @since 5.5.0
 */

/**
 * Taxonomies XML sitemap provider.
 *
 * @since 5.5.0
 */
class WP_Sitemaps_Taxonomies extends WP_Sitemaps_Provider {
    /**
     * WP_Sitemaps_Taxonomies constructor.
     *
     * @since 5.5.0
     */
    public function __construct() {
        $this->name        = 'taxonomies';
        $this->object_type = 'term';
    }

    /**
     * Returns all public, registered taxonomies.
     *
     * @since 5.5.0
     *
     * @return WP_Taxonomy[] Array of registered taxonomy objects keyed by their name.
     */
    public function get_object_subtypes() {
        $taxonomies = get_taxonomies( array( 'public' => true ), 'objects' );

        $taxonomies = array_filter( $taxonomies, 'is_taxonomy_viewable' );

        /**
         * Filters the list of taxonomy object subtypes available within the sitemap.
         *
         * @since 5.5.0
         *
         * @param WP_Taxonomy[] $taxonomies Array of registered taxonomy objects keyed by their name.
         */
        return apply_filters( 'wp_sitemaps_taxonomies', $taxonomies );
    }

    /**
     * Gets a URL list for a taxonomy sitemap.
     *
     * @since 5.5.0
     * @since 5.9.0 Renamed `$taxonomy` to `$object_subtype` to match parent class
     *              for PHP 8 named parameter support.
     *
     * @param int    $page_num       Page of results.
     * @param string $object_subtype Optional. Taxonomy name. Default empty.
     * @return array[] Array of URL information for a sitemap.
     */
    public function get_url_list( $page_num, $object_subtype = '' ) {
        // Restores the more descriptive, specific name for use within this method.
        $taxonomy = $object_subtype;

        $supported_types = $this->get_object_subtypes();

        // Bail early if the queried taxonomy is not supported.
        if ( ! isset( $supported_types[ $taxonomy ] ) ) {
            return array();
        }

        /**
         * Filters the taxonomies URL list before it is generated.
         *
         * Returning a non-null value will effectively short-circuit the generation,
         * returning that value instead.
         *
         * @since 5.5.0
         *
         * @param array[]|null $url_list The URL list. Default null.
         * @param string       $taxonomy Taxonomy name.
         * @param int          $page_num Page of results.
         */
        $url_list = apply_filters(
            'wp_sitemaps_taxonomies_pre_url_list',
            null,
            $taxonomy,
            $page_num
        );

        if ( null !== $url_list ) {
            return $url_list;
        }

        $url_list = array();

        // Offset by how many terms should be included in previous pages.
        $offset = ( $page_num - 1 ) * wp_sitemaps_get_max_urls( $this->object_type );

        $args           = $this->get_taxonomies_query_args( $taxonomy );
        $args['fields'] = 'all';
        $args['offset'] = $offset;

        $taxonomy_terms = new WP_Term_Query( $args );

        if ( ! empty( $taxonomy_terms->terms ) ) {
            foreach ( $taxonomy_terms->terms as $term ) {
                $term_link = get_term_link( $term, $taxonomy );

                if ( is_wp_error( $term_link ) ) {
                    continue;
                }

                $sitemap_entry = array(
                    'loc' => $term_link,
                );

                /**
                 * Filters the sitemap entry for an individual term.
                 *
                 * @since 5.5.0
                 * @since 6.0.0 Added `$term` argument containing the term object.
                 *
                 * @param array   $sitemap_entry Sitemap entry for the term.
                 * @param int     $term_id       Term ID.
                 * @param string  $taxonomy      Taxonomy name.
                 * @param WP_Term $term          Term object.
                 */
                $sitemap_entry = apply_filters( 'wp_sitemaps_taxonomies_entry', $sitemap_entry, $term->term_id, $taxonomy, $term );
                $url_list[]    = $sitemap_entry;
            }
        }

        return $url_list;
    }

    /**
     * Gets the max number of pages available for the object type.
     *
     * @since 5.5.0
     * @since 5.9.0 Renamed `$taxonomy` to `$object_subtype` to match parent class
     *              for PHP 8 named parameter support.
     *
     * @param string $object_subtype Optional. Taxonomy name. Default empty.
     * @return int Total number of pages.
     */
    public function get_max_num_pages( $object_subtype = '' ) {
        if ( empty( $object_subtype ) ) {
            return 0;
        }

        // Restores the more descriptive, specific name for use within this method.
        $taxonomy = $object_subtype;

        /**
         * Filters the max number of pages for a taxonomy sitemap before it is generated.
         *
         * Passing a non-null value will short-circuit the generation,
         * returning that value instead.
         *
         * @since 5.5.0
         *
         * @param int|null $max_num_pages The maximum number of pages. Default null.
         * @param string   $taxonomy      Taxonomy name.
         */
        $max_num_pages = apply_filters( 'wp_sitemaps_taxonomies_pre_max_num_pages', null, $taxonomy );

        if ( null !== $max_num_pages ) {
            return $max_num_pages;
        }

        $term_count = wp_count_terms( $this->get_taxonomies_query_args( $taxonomy ) );

        return (int) ceil( (int) $term_count / wp_sitemaps_get_max_urls( $this->object_type ) );
    }

    /**
     * Returns the query args for retrieving taxonomy terms to list in the sitemap.
     *
     * @since 5.5.0
     *
     * @param string $taxonomy Taxonomy name.
     * @return array Array of WP_Term_Query arguments.
     */
    protected function get_taxonomies_query_args( $taxonomy ) {
        /**
         * Filters the taxonomy terms query arguments.
         *
         * Allows modification of the taxonomy query arguments before querying.
         *
         * @see WP_Term_Query for a full list of arguments
         *
         * @since 5.5.0
         *
         * @param array  $args     Array of WP_Term_Query arguments.
         * @param string $taxonomy Taxonomy name.
         */
        $args = apply_filters(
            'wp_sitemaps_taxonomies_query_args',
            array(
                'taxonomy'               => $taxonomy,
                'orderby'                => 'term_order',
                'number'                 => wp_sitemaps_get_max_urls( $this->object_type ),
                'hide_empty'             => true,
                'hierarchical'           => false,
                'update_term_meta_cache' => false,
            ),
            $taxonomy
        );

        return $args;
    }
}