'id'     => array(
						'description' => __( 'The ID for the autosave.' ),
						'type'        => 'integer',
					),
				),
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( $this, 'get_item' ),
					'permission_callback' => array( $this->revisions_controller, 'get_item_permissions_check' ),
					'args'                => array(
						'context' => $this->get_context_param( array( 'default' => 'view' ) ),
					),
				),
				'schema' => array( $this, 'get_public_item_schema' ),
			)
		);
	}

	/**
	 * Prepares the item for the REST response.
	 *
	 * @since 6.4.0
	 *
	 * @param WP_Post         $item    Post revision object.
	 * @param WP_REST_Request $request Request object.
	 * @return WP_REST_Response Response object.
	 */
	public function prepare_item_for_response( $item, $request ) {
		$template = _build_block_template_result_from_post( $item );
		$response = $this->parent_controller->prepare_item_for_response( $template, $request );

		$fields = $this->get_fields_for_response( $request );
		$data   = $response->get_data();

		if ( in_array( 'parent', $fields, true ) ) {
			$data['parent'] = (int) $item->post_parent;
		}

		$context = ! empty( $request['context'] ) ? $request['context'] : 'view';
		$data    = $this->filter_response_by_context( $data, $context );

		// Wrap the data in a response object.
		$response = new WP_REST_Response( $data );

		if ( rest_is_field_included( '_links', $fields ) || rest_is_field_included( '_embedded', $fields ) ) {
			$links = $this->prepare_links( $template );
			$response->add_links( $links );
		}

		return $response;
	}

	/**
	 * Gets the autosave, if the ID is valid.
	 *
	 * @since 6.4.0
	 *
	 * @param WP_REST_Request $request Full details about the request.
	 * @return WP_Post|WP_Error Autosave post object if ID is valid, WP_Error otherwise.
	 */
	public function get_item( $request ) {
		$parent = $this->get_parent( $request['parent'] );
		if ( is_wp_error( $parent ) ) {
			return $parent;
		}

		$autosave = wp_get_post_autosave( $parent->ID );

		if ( ! $autosave ) {
			return new WP_Error(
				'rest_post_no_autosave',
				__( 'There is no autosave revision for this template.' ),
				array( 'status' => 404 )
			);
		}

		$response = $this->prepare_item_for_response( $autosave, $request );
		return $response;
	}

	/**
	 * Get the parent post.
	 *
	 * @since 6.4.0
	 *
	 * @param int $parent_id Supplied ID.
	 * @return WP_Post|WP_Error Post object if ID is valid, WP_Error otherwise.
	 */
	protected function get_parent( $parent_id ) {
		return $this->revisions_controller->get_parent( $parent_id );
	}

	/**
	 * Prepares links for the request.
	 *
	 * @since 6.4.0
	 *
	 * @param WP_Block_Template $template Template.
	 * @return array Links for the given post.
	 */
	protected function prepare_links( $template ) {
		$links = array(
			'self'   => array(
				'href' => rest_url( sprintf( '/%s/%s/%s/%s/%d', $this->namespace, $this->parent_base, $template->id, $this->rest_base, $template->wp_id ) ),
			),
			'parent' => array(
				'href' => rest_url( sprintf( '/%s/%s/%s', $this->namespace, $this->parent_base, $template->id ) ),
			),
		);

		return $links;
	}

	/**
	 * Retrieves the autosave's schema, conforming to JSON Schema.
	 *
	 * @since 6.4.0
	 *
	 * @return array Item schema data.
	 */
	public function get_item_schema() {
		if ( $this->schema ) {
			return $this->add_additional_fields_schema( $this->schema );
		}

		$this->schema = $this->revisions_controller->get_item_schema();

		return $this->add_additional_fields_schema( $this->schema );
	}
}