Retrieves the revision's schema, conforming to JSON Schema.
	 *
	 * @since 4.7.0
	 *
	 * @return array Item schema data.
	 */
	public function get_item_schema() {
		if ( $this->schema ) {
			return $this->add_additional_fields_schema( $this->schema );
		}

		$schema = array(
			'$schema'    => 'http://json-schema.org/draft-04/schema#',
			'title'      => "{$this->parent_post_type}-revision",
			'type'       => 'object',
			// Base properties for every Revision.
			'properties' => array(
				'author'       => array(
					'description' => __( 'The ID for the author of the revision.' ),
					'type'        => 'integer',
					'context'     => array( 'view', 'edit', 'embed' ),
				),
				'date'         => array(
					'description' => __( "The date the revision was published, in the site's timezone." ),
					'type'        => 'string',
					'format'      => 'date-time',
					'context'     => array( 'view', 'edit', 'embed' ),
				),
				'date_gmt'     => array(
					'description' => __( 'The date the revision was published, as GMT.' ),
					'type'        => 'string',
					'format'      => 'date-time',
					'context'     => array( 'view', 'edit' ),
				),
				'guid'         => array(
					'description' => __( 'GUID for the revision, as it exists in the database.' ),
					'type'        => 'string',
					'context'     => array( 'view', 'edit' ),
				),
				'id'           => array(
					'description' => __( 'Unique identifier for the revision.' ),
					'type'        => 'integer',
					'context'     => array( 'view', 'edit', 'embed' ),
				),
				'modified'     => array(
					'description' => __( "The date the revision was last modified, in the site's timezone." ),
					'type'        => 'string',
					'format'      => 'date-time',
					'context'     => array( 'view', 'edit' ),
				),
				'modified_gmt' => array(
					'description' => __( 'The date the revision was last modified, as GMT.' ),
					'type'        => 'string',
					'format'      => 'date-time',
					'context'     => array( 'view', 'edit' ),
				),
				'parent'       => array(
					'description' => __( 'The ID for the parent of the revision.' ),
					'type'        => 'integer',
					'context'     => array( 'view', 'edit', 'embed' ),
				),
				'slug'         => array(
					'description' => __( 'An alphanumeric identifier for the revision unique to its type.' ),
					'type'        => 'string',
					'context'     => array( 'view', 'edit', 'embed' ),
				),
			),
		);

		$parent_schema = $this->parent_controller->get_item_schema();

		if ( ! empty( $parent_schema['properties']['title'] ) ) {
			$schema['properties']['title'] = $parent_schema['properties']['title'];
		}

		if ( ! empty( $parent_schema['properties']['content'] ) ) {
			$schema['properties']['content'] = $parent_schema['properties']['content'];
		}

		if ( ! empty( $parent_schema['properties']['excerpt'] ) ) {
			$schema['properties']['excerpt'] = $parent_schema['properties']['excerpt'];
		}

		if ( ! empty( $parent_schema['properties']['guid'] ) ) {
			$schema['properties']['guid'] = $parent_schema['properties']['guid'];
		}

		$schema['properties']['meta'] = $this->meta->get_field_schema();

		$this->schema = $schema;

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

	/**
	 * Retrieves the query params for collections.
	 *
	 * @since 4.7.0
	 *
	 * @return array Collection parameters.
	 */
	public function get_collection_params() {
		$query_params = parent::get_collection_params();

		$query_params['context']['default'] = 'view';

		unset( $query_params['per_page']['default'] );

		$query_params['exclude'] = array(
			'description' => __( 'Ensure result set excludes specific IDs.' ),
			'type'        => 'array',
			'items'       => array(
				'type' => 'integer',
			),
			'default'     => array(),
		);

		$query_params['include'] = array(
			'description' => __( 'Limit result set to specific IDs.' ),
			'type'        => 'array',
			'items'       => array(
				'type' => 'integer',
			),
			'default'     => array(),
		);

		$query_params['offset'] = array(
			'description' => __( 'Offset the result set by a specific number of items.' ),
			'type'        => 'integer',
		);

		$query_params['order'] = array(
			'description' => __( 'Order sort attribute ascending or descending.' ),
			'type'        => 'string',
			'default'     => 'desc',
			'enum'        => array( 'asc', 'desc' ),
		);

		$query_params['orderby'] = array(
			'description' => __( 'Sort collection by object attribute.' ),
			'type'        => 'string',
			'default'     => 'date',
			'enum'        => array(
				'date',
				'id',
				'include',
				'relevance',
				'slug',
				'include_slugs',
				'title',
			),
		);

		return $query_params;
	}

	/**
	 * Checks the post excerpt and prepare it for single post output.
	 *
	 * @since 4.7.0
	 *
	 * @param string  $excerpt The post excerpt.
	 * @param WP_Post $post    Post revision object.
	 * @return string Prepared excerpt or empty string.
	 */
	protected function prepare_excerpt_response( $excerpt, $post ) {

		/** This filter is documented in wp-includes/post-template.php */
		$excerpt = apply_filters( 'the_excerpt', $excerpt, $post );

		if ( empty( $excerpt ) ) {
			return '';
		}

		return $excerpt;
	}
}
ller->get_items,
	 * but global styles does not require as many parameters.
	 *
	 * @since 6.3.0
	 *
	 * @param WP_REST_Request $request The request instance.
	 * @return WP_REST_Response|WP_Error
	 */
	public function get_items( $request ) {
		$parent = $this->get_parent( $request['parent'] );

		if ( is_wp_error( $parent ) ) {
			return $parent;
		}

		$global_styles_config = $this->get_decoded_global_styles_json( $parent->post_content );

		if ( is_wp_error( $global_styles_config ) ) {
			return $global_styles_config;
		}

		if ( wp_revisions_enabled( $parent ) ) {
			$registered = $this->get_collection_params();
			$query_args = array(
				'post_parent'    => $parent->ID,
				'post_type'      => 'revision',
				'post_status'    => 'inherit',
				'posts_per_page' => -1,
				'orderby'        => 'date ID',
				'order'          => 'DESC',
			);

			$parameter_mappings = array(
				'offset'   => 'offset',
				'page'     => 'paged',
				'per_page' => 'posts_per_page',
			);

			foreach ( $parameter_mappings as $api_param => $wp_param ) {
				if ( isset( $registered[ $api_param ], $request[ $api_param ] ) ) {
					$query_args[ $wp_param ] = $request[ $api_param ];
				}
			}

			$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 = (int) 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'];
		}

		$response = array();

		foreach ( $revisions as $revision ) {
			$data       = $this->prepare_item_for_response( $revision, $request );
			$response[] = $this->prepare_response_for_collection( $data );
		}

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

		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;
	}

	/**
	 * Prepares the revision for the REST response.
	 *
	 * @since 6.3.0
	 * @since 6.6.0 Added resolved URI links to the response.
	 *
	 * @param WP_Post         $post    Post revision object.
	 * @param WP_REST_Request $request Request object.
	 * @return WP_REST_Response|WP_Error Response object.
	 */
	public function prepare_item_for_response( $post, $request ) {
		$parent               = $this->get_parent( $request['parent'] );
		$global_styles_config = $this->get_decoded_global_styles_json( $post->post_content );

		if ( is_wp_error( $global_styles_config ) ) {
			return $global_styles_config;
		}

		$fields     = $this->get_fields_for_response( $request );
		$data       = array();
		$theme_json = null;

		if ( ! empty( $global_styles_config['styles'] ) || ! empty( $global_styles_config['settings'] ) ) {
			$theme_json           = new WP_Theme_JSON( $global_styles_config, 'custom' );
			$global_styles_config = $theme_json->get_raw_data();
			if ( rest_is_field_included( 'settings', $fields ) ) {
				$data['settings'] = ! empty( $global_styles_config['settings'] ) ? $global_styles_config['settings'] : new stdClass();
			}
			if ( rest_is_field_included( 'styles', $fields ) ) {
				$data['styles'] = ! empty( $global_styles_config['styles'] ) ? $global_styles_config['styles'] : new stdClass();
			}
		}

		if ( rest_is_field_included( 'author', $fields ) ) {
			$data['author'] = (int) $post->post_author;
		}

		if ( rest_is_field_included( 'date', $fields ) ) {
			$data['date'] = $this->prepare_date_response( $post->post_date_gmt, $post->post_date );
		}

		if ( rest_is_field_included( 'date_gmt', $fields ) ) {
			$data['date_gmt'] = $this->prepare_date_response( $post->post_date_gmt );
		}

		if ( rest_is_field_included( 'id', $fields ) ) {
			$data['id'] = (int) $post->ID;
		}

		if ( rest_is_field_included( 'modified', $fields ) ) {
			$data['modified'] = $this->prepare_date_response( $post->post_modified_gmt, $post->post_modified );
		}

		if ( rest_is_field_included( 'modified_gmt', $fields ) ) {
			$data['modified_gmt'] = $this->prepare_date_response( $post->post_modified_gmt );
		}

		if ( rest_is_field_included( 'parent', $fields ) ) {
			$data['parent'] = (int) $parent->ID;
		}

		$context             = ! empty( $request['context'] ) ? $request['context'] : 'view';
		$data                = $this->add_additional_fields_to_object( $data, $request );
		$data                = $this->filter_response_by_context( $data, $context );
		$response            = rest_ensure_response( $data );
		$resolved_theme_uris = WP_Theme_JSON_Resolver::get_resolved_theme_uris( $theme_json );

		if ( ! empty( $resolved_theme_uris ) ) {
			$response->add_links(
				array(
					'https://api.w.org/theme-file' => $resolved_theme_uris,
				)
			);
		}

		return $response;
	}

	/**
	 * Retrieves the revision's schema, conforming to JSON Schema.
	 *
	 * @since 6.3.0
	 * @since 6.6.0 Merged parent and parent controller schema data.
	 *
	 * @return array Item schema data.
	 */
	public function get_item_schema() {
		if ( $this->schema ) {
			return $this->add_additional_fields_schema( $this->schema );
		}

		$schema               = parent::get_item_schema();
		$parent_schema        = $this->parent_controller->get_item_schema();
		$schema['properties'] = array_merge( $schema['properties'], $parent_schema['properties'] );

		unset(
			$schema['properties']['guid'],
			$schema['properties']['slug'],
			$schema['properties']['meta'],
			$schema['properties']['content'],
			$schema['properties']['title']
		);

			$this->schema = $schema;

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

	/**
	 * Retrieves the query params for collections.
	 * Removes params that are not supported by global styles revisions.
	 *
	 * @since 6.6.0
	 *
	 * @return array Collection parameters.
	 */
	public function get_collection_params() {
		$query_params = parent::get_collection_params();
		unset(
			$query_params['exclude'],
			$query_params['include'],
			$query_params['search'],
			$query_params['order'],
			$query_params['orderby']
		);
		return $query_params;
	}
}