<?php
/**
 * REST API: WP_REST_Term_Search_Handler class
 *
 * @package WordPress
 * @subpackage REST_API
 * @since 5.6.0
 */

/**
 * Core class representing a search handler for terms in the REST API.
 *
 * @since 5.6.0
 *
 * @see WP_REST_Search_Handler
 */
class WP_REST_Term_Search_Handler extends WP_REST_Search_Handler {

    /**
     * Constructor.
     *
     * @since 5.6.0
     */
    public function __construct() {
        $this->type = 'term';

        $this->subtypes = array_values(
            get_taxonomies(
                array(
                    'public'       => true,
                    'show_in_rest' => true,
                ),
                'names'
            )
        );
    }

    /**
     * Searches terms for a given search request.
     *
     * @since 5.6.0
     *
     * @param WP_REST_Request $request Full REST request.
     * @return array {
     *     Associative array containing found IDs and total count for the matching search results.
     *
     *     @type int[]               $ids   Found term IDs.
     *     @type string|int|WP_Error $total Numeric string containing the number of terms in that
     *                                      taxonomy, 0 if there are no results, or WP_Error if
     *                                      the requested taxonomy does not exist.
     * }
     */
    public function search_items( WP_REST_Request $request ) {
        $taxonomies = $request[ WP_REST_Search_Controller::PROP_SUBTYPE ];
        if ( in_array( WP_REST_Search_Controller::TYPE_ANY, $taxonomies, true ) ) {
            $taxonomies = $this->subtypes;
        }

        $page     = (int) $request['page'];
        $per_page = (int) $request['per_page'];

        $query_args = array(
            'taxonomy'   => $taxonomies,
            'hide_empty' => false,
            'offset'     => ( $page - 1 ) * $per_page,
            'number'     => $per_page,
        );

        if ( ! empty( $request['search'] ) ) {
            $query_args['search'] = $request['search'];
        }

        if ( ! empty( $request['exclude'] ) ) {
            $query_args['exclude'] = $request['exclude'];
        }

        if ( ! empty( $request['include'] ) ) {
            $query_args['include'] = $request['include'];
        }

        /**
         * Filters the query arguments for a REST API term search request.
         *
         * Enables adding extra arguments or setting defaults for a term search request.
         *
         * @since 5.6.0
         *
         * @param array           $query_args Key value array of query var to query value.
         * @param WP_REST_Request $request    The request used.
         */
        $query_args = apply_filters( 'rest_term_search_query', $query_args, $request );

        $query       = new WP_Term_Query();
        $found_terms = $query->query( $query_args );
        $found_ids   = wp_list_pluck( $found_terms, 'term_id' );

        unset( $query_args['offset'], $query_args['number'] );

        $total = wp_count_terms( $query_args );

        // wp_count_terms() can return a falsey value when the term has no children.
        if ( ! $total ) {
            $total = 0;
        }

        return array(
            self::RESULT_IDS   => $found_ids,
            self::RESULT_TOTAL => $total,
        );
    }

    /**
     * Prepares the search result for a given term ID.
     *
     * @since 5.6.0
     *
     * @param int   $id     Term ID.
     * @param array $fields Fields to include for the term.
     * @return array {
     *     Associative array containing fields for the term based on the `$fields` parameter.
     *
     *     @type int    $id    Optional. Term ID.
     *     @type string $title Optional. Term name.
     *     @type string $url   Optional. Term permalink URL.
     *     @type string $type  Optional. Term taxonomy name.
     * }
     */
    public function prepare_item( $id, array $fields ) {
        $term = get_term( $id );

        $data = array();

        if ( in_array( WP_REST_Search_Controller::PROP_ID, $fields, true ) ) {
            $data[ WP_REST_Search_Controller::PROP_ID ] = (int) $id;
        }
        if ( in_array( WP_REST_Search_Controller::PROP_TITLE, $fields, true ) ) {
            $data[ WP_REST_Search_Controller::PROP_TITLE ] = $term->name;
        }
        if ( in_array( WP_REST_Search_Controller::PROP_URL, $fields, true ) ) {
            $data[ WP_REST_Search_Controller::PROP_URL ] = get_term_link( $id );
        }
        if ( in_array( WP_REST_Search_Controller::PROP_TYPE, $fields, true ) ) {
            $data[ WP_REST_Search_Controller::PROP_TYPE ] = $term->taxonomy;
        }

        return $data;
    }

    /**
     * Prepares links for the search result of a given ID.
     *
     * @since 5.6.0
     *
     * @param int $id Item ID.
     * @return array[] Array of link arrays for the given item.
     */
    public function prepare_item_links( $id ) {
        $term = get_term( $id );

        $links = array();

        $item_route = rest_get_route_for_term( $term );
        if ( $item_route ) {
            $links['self'] = array(
                'href'       => rest_url( $item_route ),
                'embeddable' => true,
            );
        }

        $links['about'] = array(
            'href' => rest_url( sprintf( 'wp/v2/taxonomies/%s', $term->taxonomy ) ),
        );

        return $links;
    }
}