$this->parent_post_type  = $parent_post_type;

		$this->namespace         = 'wp/v2';

		$this->rest_base         = 'revisions';

		$post_type_object        = get_post_type_object( $parent_post_type );

		$this->parent_base       = ! empty( $post_type_object->rest_base ) ? $post_type_object->rest_base : $post_type_object->name;

		register_rest_route(

			$this->namespace,

			'/' . $this->parent_base . '/(?P<parent>[\d]+)/' . $this->rest_base,

				'args'   => array(

					'parent' => array(

						'description' => __( 'The ID for the parent of the object.' ),

						'type'        => 'integer',

				array(

					'methods'             => WP_REST_Server::READABLE,

					'callback'            => array( $this, 'get_items' ),

					'permission_callback' => array( $this, 'get_items_permissions_check' ),

					'args'                => $this->get_collection_params(),

				),

				'schema' => array( $this, 'get_public_item_schema' ),

			)

		);

		register_rest_route(

			$this->namespace,

			'/' . $this->parent_base . '/(?P<parent>[\d]+)/' . $this->rest_base . '/(?P<id>[\d]+)',

			array(

				'args'   => array(

					'parent' => array(

						'description' => __( 'The ID for the parent of the object.' ),

						'type'        => 'integer',

					),

					'id'     => array(

						'description' => __( 'Unique identifier for the object.' ),

						'type'        => 'integer',

					),

				),

				array(

					'methods'             => WP_REST_Server::READABLE,

					'callback'            => array( $this, 'get_item' ),

					'permission_callback' => array( $this, 'get_item_permissions_check' ),

					'args'                => array(

						'context' => $this->get_context_param( array( 'default' => 'view' ) ),

					),

				),

				array(

					'methods'             => WP_REST_Server::DELETABLE,

					'callback'            => array( $this, 'delete_item' ),

					'permission_callback' => array( $this, 'delete_item_permissions_check' ),

					'args'                => array(

						'force' => array(

							'type'        => 'boolean',

							'default'     => false,

							'description' => __( 'Required to be true, as revisions do not support trashing.' ),

						),

					),

				),

				'schema' => array( $this, 'get_public_item_schema' ),

			)

		);

		// Ensure a search string is set in case the orderby is set to 'relevance'.

		if ( ! empty( $request['orderby'] ) && 'relevance' === $request['orderby'] && empty( $request['search'] ) ) {

			return new WP_Error( 'rest_no_search_term_defined', __( 'You need to define a search term to order by relevance.' ), array( 'status' => 400 ) );

		}

		// Ensure an include parameter is set in case the orderby is set to 'include'.

		if ( ! empty( $request['orderby'] ) && 'include' === $request['orderby'] && empty( $request['include'] ) ) {

			return new WP_Error( 'rest_orderby_include_missing_include', __( 'You need to define an include parameter to order by include.' ), array( 'status' => 400 ) );

		}

		if ( wp_revisions_enabled( $parent ) ) {

			$registered = $this->get_collection_params();

			$args       = array(

				'post_parent'      => $parent->ID,

				'post_type'        => 'revision',

				'post_status'      => 'inherit',

				'posts_per_page'   => -1,

				'orderby'          => 'date ID',

				'order'            => 'DESC',

				'suppress_filters' => true,

			);

			$parameter_mappings = array(

				'exclude'  => 'post__not_in',

				'include'  => 'post__in',

				'offset'   => 'offset',

				'order'    => 'order',

				'orderby'  => 'orderby',

				'page'     => 'paged',

				'per_page' => 'posts_per_page',

				'search'   => 's',

			);

			foreach ( $parameter_mappings as $api_param => $wp_param ) {

				if ( isset( $registered[ $api_param ], $request[ $api_param ] ) ) {

					$args[ $wp_param ] = $request[ $api_param ];

				}

			}

			// For backward-compatibility, 'date' needs to resolve to 'date ID'.

			if ( isset( $args['orderby'] ) && 'date' === $args['orderby'] ) {

				$args['orderby'] = 'date ID';

			}

			/** This filter is documented in wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php */

			$args       = apply_filters( 'rest_revision_query', $args, $request );

			$query_args = $this->prepare_items_query( $args, $request );

			$revisions_query = new WP_Query();

			$revisions       = $revisions_query->query( $query_args );

			$offset          = isset( $query_args['offset'] ) ? (int) $query_args['offset'] : 0;

			$page            = (int) $query_args['paged'];

			$total_revisions = $revisions_query->found_posts;

			if ( $total_revisions < 1 ) {

				// Out-of-bounds, run the query again without LIMIT for total count.

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

				$count_query = new WP_Query();

				$count_query->query( $query_args );

				$total_revisions = $count_query->found_posts;

			}

			if ( $revisions_query->query_vars['posts_per_page'] > 0 ) {

				$max_pages = ceil( $total_revisions / (int) $revisions_query->query_vars['posts_per_page'] );

			} else {

				$max_pages = $total_revisions > 0 ? 1 : 0;

			}

			if ( $total_revisions > 0 ) {

				if ( $offset >= $total_revisions ) {

					return new WP_Error( 'rest_revision_invalid_offset_number', __( 'The offset number requested is larger than or equal to the number of available revisions.' ), array( 'status' => 400 ) );

				} elseif ( ! $offset && $page > $max_pages ) {

					return new WP_Error( 'rest_revision_invalid_page_number', __( 'The page number requested is larger than the number of pages available.' ), array( 'status' => 400 ) );

				}

			}

		} else {

			$revisions       = array();

			$total_revisions = 0;

			$max_pages       = 0;

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

		}

			$data       = $this->prepare_item_for_response( $revision, $request );

		$response = rest_ensure_response( $response );

		$response->header( 'X-WP-Total', (int) $total_revisions );

		$response->header( 'X-WP-TotalPages', (int) $max_pages );

		$request_params = $request->get_query_params();

		$base           = add_query_arg( urlencode_deep( $request_params ), rest_url( sprintf( '%s/%s/%d/%s', $this->namespace, $this->parent_base, $request['parent'], $this->rest_base ) ) );

		if ( $page > 1 ) {

			$prev_page = $page - 1;

			if ( $prev_page > $max_pages ) {

				$prev_page = $max_pages;

			}

			$prev_link = add_query_arg( 'page', $prev_page, $base );

			$response->link_header( 'prev', $prev_link );

		}

		if ( $max_pages > $page ) {

			$next_page = $page + 1;

			$next_link = add_query_arg( 'page', $next_page, $base );

			$response->link_header( 'next', $next_link );

		}

		return $response;