text: <?php
  /**
   * REST API: WP_REST_Search_Controller class
   *
   * @package WordPress
   * @subpackage REST_API
   * @since 5.0.0
   */
  
  /**
   * Core class to search through all WordPress content via the REST API.
   *
   * @since 5.0.0
   *
   * @see WP_REST_Controller
   */
  class WP_REST_Search_Controller extends WP_REST_Controller {
  
  	/**
  	 * ID property name.
  	 */
  	const PROP_ID = 'id';
  
  	/**
  	 * Title property name.
  	 */
  	const PROP_TITLE = 'title';
  
  	/**
  	 * URL property name.
  	 */
  	const PROP_URL = 'url';
  
  	/**
  	 * Type property name.
  	 */
  	const PROP_TYPE = 'type';
  
  	/**
  	 * Subtype property name.
  	 */
  	const PROP_SUBTYPE = 'subtype';
  
  	/**
  	 * Identifier for the 'any' type.
  	 */
  	const TYPE_ANY = 'any';
  
  	/**
  	 * Search handlers used by the controller.
  	 *
  	 * @since 5.0.0
  	 * @var array
  	 */
  	protected $search_handlers = array();
  
  	/**
  	 * Constructor.
  	 *
  	 * @since 5.0.0
  	 *
  	 * @param array $search_handlers List of search handlers to use in the controller. Each search
  	 *                               handler instance must extend the `WP_REST_Search_Handler` class.
  	 */
  	public function __construct( array $search_handlers ) {
  		$this->namespace = 'wp/v2';
  		$this->rest_base = 'search';
  
  		foreach ( $search_handlers as $search_handler ) {
  			if ( ! $search_handler instanceof WP_REST_Search_Handler ) {
  				_doing_it_wrong(
  					__METHOD__,
  					/* translators: %s: PHP class name. */
  					sprintf( __( 'REST search handlers must extend the %s class.' ), 'WP_REST_Search_Handler' ),
  					'5.0.0'
  				);
  				continue;
  			}
  
  			$this->search_handlers[ $search_handler->get_type() ] = $search_handler;
  		}
  	}
  
  	/**
  	 * Registers the routes for the objects of the controller.
  	 *
  	 * @since 5.0.0
  	 *
  	 * @see register_rest_route()
  	 */
  	public function register_routes() {
  		register_rest_route(
  			$this->namespace,
  			'/' . $this->rest_base,
  			array(
  				array(
  					'methods'             => WP_REST_Server::READABLE,
  					'callback'            => array( $this, 'get_items' ),
  					'permission_callback' => array( $this, 'get_items_permission_check' ),
  					'args'                => $this->get_collection_params(),
  				),
  				'schema' => array( $this, 'get_public_item_schema' ),
  			)
  		);
  	}
  
  	/**
  	 * Checks if a given request has access to search content.
  	 *
  	 * @since 5.0.0
  	 *
  	 * @param WP_REST_Request $request Full details about the request.
  	 * @return true|WP_Error True if the request has search access, WP_Error object otherwise.
  	 */
  	public function get_items_permission_check( $request ) {
  		return true;
  	}
  
  	/**
  	 * Retrieves a collection of search results.
  	 *
  	 * @since 5.0.0
  	 *
  	 * @param WP_REST_Request $request Full details about the request.
  	 * @return WP_REST_Response|WP_Error Response object on success, or WP_Error object on failure.
  	 */
  	public function get_items( $request ) {
  		$handler = $this->get_search_handler( $request );
  		if ( is_wp_error( $handler ) ) {
  			return $handler;
  		}
  
  		$result = $handler->search_items( $request );
  
  		if ( ! isset( $result[ WP_REST_Search_Handler::RESULT_IDS ] ) || ! is_array( $result[ WP_REST_Search_Handler::RESULT_IDS ] ) || ! isset( $result[ WP_REST_Search_Handler::RESULT_TOTAL ] ) ) {
  			return new WP_Error(
  				'rest_search_handler_error',
  				__( 'Internal search handler error.' ),
  				array( 'status' => 500 )
  			);
  		}
  
  		$ids = array_map( 'absint', $result[ WP_REST_Search_Handler::RESULT_IDS ] );
  
  		$results = array();
  
  		foreach ( $ids as $id ) {
  			$data      = $this->prepare_item_for_response( $id, $request );
  			$results[] = $this->prepare_response_for_collection( $data );
  		}
  
  		$total     = (int) $result[ WP_REST_Search_Handler::RESULT_TOTAL ];
  		$page      = (int) $request['page'];
  		$per_page  = (int) $request['per_page'];
  		$max_pages = ceil( $total / $per_page );
  
  		if ( $page > $max_pages && $total > 0 ) {
  			return new WP_Error(
  				'rest_search_invalid_page_number',
  				__( 'The page number requested is larger than the number of pages available.' ),
  				array( 'status' => 400 )
  			);
  		}
  
  		$response = rest_ensure_response( $results );
  		$response->header( 'X-WP-Total', $total );
  		$response->header( 'X-WP-TotalPages', $max_pages );
  
  		$request_params = $request->get_query_params();
  		$base           = add_query_arg( urlencode_deep( $request_params ), rest_url( sprintf( '%s/%s', $this->namespace, $this->rest_base ) ) );
  
  		if ( $page > 1 ) {
  			$prev_link = add_query_arg( 'page', $page - 1, $base );
  			$response->link_header( 'prev', $prev_link );
  		}
  		if ( $page < $max_pages ) {
  			$next_link = add_query_arg( 'page', $page + 1, $base );
  			$response->link_header( 'next', $next_link );
  		}
  
  		return $response;
  	}
  
  	/**
  	 * Prepares a single search result for response.
  	 *
  	 * @since 5.0.0
  	 *
  	 * @param int             $id      ID of the item to prepare.
  	 * @param WP_REST_Request $request Request object.
  	 * @return WP_REST_Response Response object.
  	 */
  	public function prepare_item_for_response( $id, $request ) {
  		$handler = $this->get_search_handler( $request );
  		if ( is_wp_error( $handler ) ) {
  			return new WP_REST_Response();
  		}
  
  		$fields = $this->get_fields_for_response( $request );
  
  		$data = $handler->prepare_item( $id, $fields );
  		$data = $this->add_additional_fields_to_object( $data, $request );
  
  		$context = ! empty( $request['context'] ) ? $request['context'] : 'view';
  		$data    = $this->filter_response_by_context( $data, $context );
  
  		$response = rest_ensure_response( $data );
  
  		$links               = $handler->prepare_item_links( $id );
  		$links['collection'] = array(
  			'href' => rest_url( sprintf( '%s/%s', $this->namespace, $this->rest_base ) ),
  		);
  		$response->add_links( $links );
  
  		return $response;
  	}
  
  	/**
  	 * Retrieves the item schema, conforming to JSON Schema.
  	 *
  	 * @since 5.0.0
  	 *
  	 * @return array Item schema data.
  	 */
  	public function get_item_schema() {
  		if ( $this->schema ) {
  			return $this->add_additional_fields_schema( $this->schema );
  		}
  
  		$types    = array();
  		$subtypes = array();
  
  		foreach ( $this->search_handlers as $search_handler ) {
  			$types[]  = $search_handler->get_type();
  			$subtypes = array_merge( $subtypes, $search_handler->get_subtypes() );
  		}
  
  		$types    = array_unique( $types );
  		$subtypes = array_unique( $subtypes );
  
  		$schema = array(
  			'$schema'    => 'http://json-schema.org/draft-04/schema#',
  			'title'      => 'search-result',
  			'type'       => 'object',
  			'properties' => array(
  				self::PROP_ID      => array(
  					'description' => __( 'Unique identifier for the object.' ),
  					'type'        => 'integer',
  					'context'     => array( 'view', 'embed' ),
  					'readonly'    => true,
  				),
  				self::PROP_TITLE   => array(
  					'description' => __( 'The title for the object.' ),
  					'type'        => 'string',
  					'context'     => array( 'view', 'embed' ),
  					'readonly'    => true,
  				),
  				self::PROP_URL     => array(
  					'description' => __( 'URL to the object.' ),
  					'type'        => 'string',
  					'format'      => 'uri',
  					'context'     => array( 'view', 'embed' ),
  					'readonly'    => true,
  				),
  				self::PROP_TYPE    => array(
  					'description' => __( 'Object type.' ),
  					'type'        => 'string',
  					'enum'        => $types,
  					'context'     => array( 'view', 'embed' ),
  					'readonly'    => true,
  				),
  				self::PROP_SUBTYPE => array(
  					'description' => __( 'Object subtype.' ),
  					'type'        => 'string',
  					'enum'        => $subtypes,
  					'context'     => array( 'view', 'embed' ),
  					'readonly'    => true,
  				),
  			),
  		);
  
  		$this->schema = $schema;
  
  		return $this->add_additional_fields_schema( $this->schema );
  	}
  
  	/**
  	 * Retrieves the query params for the search results collection.
  	 *
  	 * @since 5.0.0
  	 *
  	 * @return array Collection parameters.
  	 */
  	public function get_collection_params() {
  		$types    = array();
  		$subtypes = array();
  
  		foreach ( $this->search_handlers as $search_handler ) {
  			$types[]  = $search_handler->get_type();
  			$subtypes = array_merge( $subtypes, $search_handler->get_subtypes() );
  		}
  
  		$types    = array_unique( $types );
  		$subtypes = array_unique( $subtypes );
  
  		$query_params = parent::get_collection_params();
  
  		$query_params['context']['default'] = 'view';
  
  		$query_params[ self::PROP_TYPE ] = array(
  			'default'     => $types[0],
  			'description' => __( 'Limit results to items of an object type.' ),
  			'type'        => 'string',
  			'enum'        => $types,
  		);
  
  		$query_params[ self::PROP_SUBTYPE ] = array(
  			'default'           => self::TYPE_ANY,
  			'description'       => __( 'Limit results to items of one or more object subtypes.' ),
  			'type'              => 'array',
  			'items'             => array(
  				'enum' => array_merge( $subtypes, array( self::TYPE_ANY ) ),
  				'type' => 'string',
  			),
  			'sanitize_callback' => array( $this, 'sanitize_subtypes' ),
  		);
  
  		return $query_params;
  	}
  
  	/**
  	 * Sanitizes the list of subtypes, to ensure only subtypes of the passed type are included.
  	 *
  	 * @since 5.0.0
  	 *
  	 * @param string|array    $subtypes  One or more subtypes.
  	 * @param WP_REST_Request $request   Full details about the request.
  	 * @param string          $parameter Parameter name.
  	 * @return array|WP_Error List of valid subtypes, or WP_Error object on failure.
  	 */
  	public function sanitize_subtypes( $subtypes, $request, $parameter ) {
  		$subtypes = wp_parse_slug_list( $subtypes );
  
  		$subtypes = rest_parse_request_arg( $subtypes, $request, $parameter );
  		if ( is_wp_error( $subtypes ) ) {
  			return $subtypes;
  		}
  
  		// 'any' overrides any other subtype.
  		if ( in_array( self::TYPE_ANY, $subtypes, true ) ) {
  			return array( self::TYPE_ANY );
  		}
  
  		$handler = $this->get_search_handler( $request );
  		if ( is_wp_error( $handler ) ) {
  			return $handler;
  		}
  
  		return array_intersect( $subtypes, $handler->get_subtypes() );
  	}
  
  	/**
  	 * Gets the search handler to handle the current request.
  	 *
  	 * @since 5.0.0
  	 *
  	 * @param WP_REST_Request $request Full details about the request.
  	 * @return WP_REST_Search_Handler|WP_Error Search handler for the request type, or WP_Error object on failure.
  	 */
  	protected function get_search_handler( $request ) {
  		$type = $request->get_param( self::PROP_TYPE );
  
  		if ( ! $type || ! isset( $this->search_handlers[ $type ] ) ) {
  			return new WP_Error(
  				'rest_search_invalid_type',
  				__( 'Invalid type parameter.' ),
  				array( 'status' => 400 )
  			);
  		}
  
  		return $this->search_handlers[ $type ];
  	}
  }
  