=> true,
							),
						),
					);
					break;

				case 'author':
					$schema['properties']['author'] = array(
						'description' => __( 'The ID for the author of the post.' ),
						'type'        => 'integer',
						'context'     => array( 'view', 'edit', 'embed' ),
					);
					break;

				case 'excerpt':
					$schema['properties']['excerpt'] = array(
						'description' => __( 'The excerpt for the post.' ),
						'type'        => 'object',
						'context'     => array( 'view', 'edit', 'embed' ),
						'arg_options' => array(
							'sanitize_callback' => null, // Note: sanitization implemented in self::prepare_item_for_database().
							'validate_callback' => null, // Note: validation implemented in self::prepare_item_for_database().
						),
						'properties'  => array(
							'raw'       => array(
								'description' => __( 'Excerpt for the post, as it exists in the database.' ),
								'type'        => 'string',
								'context'     => array( 'edit' ),
							),
							'rendered'  => array(
								'description' => __( 'HTML excerpt for the post, transformed for display.' ),
								'type'        => 'string',
								'context'     => array( 'view', 'edit', 'embed' ),
								'readonly'    => true,
							),
							'protected' => array(
								'description' => __( 'Whether the excerpt is protected with a password.' ),
								'type'        => 'boolean',
								'context'     => array( 'view', 'edit', 'embed' ),
								'readonly'    => true,
							),
						),
					);
					break;

				case 'thumbnail':
					$schema['properties']['featured_media'] = array(
						'description' => __( 'The ID of the featured media for the post.' ),
						'type'        => 'integer',
						'context'     => array( 'view', 'edit', 'embed' ),
					);
					break;

				case 'comments':
					$schema['properties']['comment_status'] = array(
						'description' => __( 'Whether or not comments are open on the post.' ),
						'type'        => 'string',
						'enum'        => array( 'open', 'closed' ),
						'context'     => array( 'view', 'edit' ),
					);
					$schema['properties']['ping_status']    = array(
						'description' => __( 'Whether or not the post can be pinged.' ),
						'type'        => 'string',
						'enum'        => array( 'open', 'closed' ),
						'context'     => array( 'view', 'edit' ),
					);
					break;

				case 'page-attributes':
					$schema['properties']['menu_order'] = array(
						'description' => __( 'The order of the post in relation to other posts.' ),
						'type'        => 'integer',
						'context'     => array( 'view', 'edit' ),
					);
					break;

				case 'post-formats':
					// Get the native post formats and remove the array keys.
					$formats = array_values( get_post_format_slugs() );

					$schema['properties']['format'] = array(
						'description' => __( 'The format for the post.' ),
						'type'        => 'string',
						'enum'        => $formats,
						'context'     => array( 'view', 'edit' ),
					);
					break;

				case 'custom-fields':
					$schema['properties']['meta'] = $this->meta->get_field_schema();
					break;

			}
		}

		if ( 'post' === $this->post_type ) {
			$schema['properties']['sticky'] = array(
				'description' => __( 'Whether or not the post should be treated as sticky.' ),
				'type'        => 'boolean',
				'context'     => array( 'view', 'edit' ),
			);
		}

		$schema['properties']['template'] = array(
			'description' => __( 'The theme file to use to display the post.' ),
			'type'        => 'string',
			'context'     => array( 'view', 'edit' ),
			'arg_options' => array(
				'validate_callback' => array( $this, 'check_template' ),
			),
		);

		$taxonomies = wp_list_filter( get_object_taxonomies( $this->post_type, 'objects' ), array( 'show_in_rest' => true ) );

		foreach ( $taxonomies as $taxonomy ) {
			$base = ! empty( $taxonomy->rest_base ) ? $taxonomy->rest_base : $taxonomy->name;

			if ( array_key_exists( $base, $schema['properties'] ) ) {
				$taxonomy_field_name_with_conflict = ! empty( $taxonomy->rest_base ) ? 'rest_base' : 'name';
				_doing_it_wrong(
					'register_taxonomy',
					sprintf(
						/* translators: 1: The taxonomy name, 2: The property name, either 'rest_base' or 'name', 3: The conflicting value. */
						__( 'The "%1$s" taxonomy "%2$s" property (%3$s) conflicts with an existing property on the REST API Posts Controller. Specify a custom "rest_base" when registering the taxonomy to avoid this error.' ),
						$taxonomy->name,
						$taxonomy_field_name_with_conflict,
						$base
					),
					'5.4.0'
				);
			}

			$schema['properties'][ $base ] = array(
				/* translators: %s: Taxonomy name. */
				'description' => sprintf( __( 'The terms assigned to the post in the %s taxonomy.' ), $taxonomy->name ),
				'type'        => 'array',
				'items'       => array(
					'type' => 'integer',
				),
				'context'     => array( 'view', 'edit' ),
			);
		}

		$schema_links = $this->get_schema_links();

		if ( $schema_links ) {
			$schema['links'] = $schema_links;
		}

		// Take a snapshot of which fields are in the schema pre-filtering.
		$schema_fields = array_keys( $schema['properties'] );

		/**
		 * Filters the post's schema.
		 *
		 * The dynamic portion of the filter, `$this->post_type`, refers to the
		 * post type slug for the controller.
		 *
		 * Possible hook names include:
		 *
		 *  - `rest_post_item_schema`
		 *  - `rest_page_item_schema`
		 *  - `rest_attachment_item_schema`
		 *
		 * @since 5.4.0
		 *
		 * @param array $schema Item schema data.
		 */
		$schema = apply_filters( "rest_{$this->post_type}_item_schema", $schema );

		// Emit a _doing_it_wrong warning if user tries to add new properties using this filter.
		$new_fields = array_diff( array_keys( $schema['properties'] ), $schema_fields );
		if ( count( $new_fields ) > 0 ) {
			_doing_it_wrong(
				__METHOD__,
				sprintf(
					/* translators: %s: register_rest_field */
					__( 'Please use %s to add new schema properties.' ),
					'register_rest_field'
				),
				'5.4.0'
			);
		}

		$this->schema = $schema;

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

	/**
	 * Retrieves Link Description Objects that should be added to the Schema for the posts collection.
	 *
	 * @since 4.9.8
	 *
	 * @return array
	 */
	protected function get_schema_links() {

		$href = rest_url( "{$this->namespace}/{$this->rest_base}/{id}" );

		$links = array();

		if ( 'attachment' !== $this->post_type ) {
			$links[] = array(
				'rel'          => 'https://api.w.org/action-publish',
				'title'        => __( 'The current user can publish this post.' ),
				'href'         => $href,
				'targetSchema' => array(
					'type'       => 'object',
					'properties' => array(
						'status' => array(
							'type' => 'string',
							'enum' => array( 'publish', 'future' ),
						),
					),
				),
			);
		}

		$links[] = array(
			'rel'          => 'https://api.w.org/action-unfiltered-html',
			'title'        => __( 'The current user can post unfiltered HTML markup and JavaScript.' ),
			'href'         => $href,
			'targetSchema' => array(
				'type'       => 'object',
				'properties' => array(
					'content' => array(
						'raw' => array(
							'type' => 'string',
						),
					),
				),
			),
		);

		if ( 'post' === $this->post_type ) {
			$links[] = array(
				'rel'          => 'https://api.w.org/action-sticky',
				'title'        => __( 'The current user can sticky this post.' ),
				'href'         => $href,
				'targetSchema' => array(
					'type'       => 'object',
					'properties' => array(
						'sticky' => array(
							'type' => 'boolean',
						),
					),
				),
			);
		}

		if ( post_type_supports( $this->post_type, 'author' ) ) {
			$links[] = array(
				'rel'          => 'https://api.w.org/action-assign-author',
				'title'        => __( 'The current user can change the author on this post.' ),
				'href'         => $href,
				'targetSchema' => array(
					'type'       => 'object',
					'properties' => array(
						'author' => array(
							'type' => 'integer',
						),
					),
				),
			);
		}

		$taxonomies = wp_list_filter( get_object_taxonomies( $this->post_type, 'objects' ), array( 'show_in_rest' => true ) );

		foreach ( $taxonomies as $tax ) {
			$tax_base = ! empty( $tax->rest_base ) ? $tax->rest_base : $tax->name;

			/* translators: %s: Taxonomy name. */
			$assign_title = sprintf( __( 'The current user can assign terms in the %s taxonomy.' ), $tax->name );
			/* translators: %s: Taxonomy name. */
			$create_title = sprintf( __( 'The current user can create terms in the %s taxonomy.' ), $tax->name );

			$links[] = array(
				'rel'          => 'https://api.w.org/action-assign-' . $tax_base,
				'title'        => $assign_title,
				'href'         => $href,
				'targetSchema' => array(
					'type'       => 'object',
					'properties' => array(
						$tax_base => array(
							'type'  => 'array',
							'items' => array(
								'type' => 'integer',
							),
						),
					),
				),
			);

			$links[] = array(
				'rel'          => 'https://api.w.org/action-create-' . $tax_base,
				'title'        => $create_title,
				'href'         => $href,
				'targetSchema' => array(
					'type'       => 'object',
					'properties' => array(
						$tax_base => array(
							'type'  => 'array',
							'items' => array(
								'type' => 'integer',
							),
						),
					),
				),
			);
		}

		return $links;
	}

	/**
	 * Retrieves the query params for the posts collection.
	 *
	 * @since 4.7.0
	 * @since 5.4.0 The `tax_relation` query parameter was added.
	 * @since 5.7.0 The `modified_after` and `modified_before` query parameters were added.
	 *
	 * @return array Collection parameters.
	 */
	public function get_collection_params() {
		$query_params = parent::get_collection_params();

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

		$query_params['after'] = array(
			'description' => __( 'Limit response to posts published after a given ISO8601 compliant date.' ),
			'type'        => 'string',
			'format'      => 'date-time',
		);

		$query_params['modified_after'] = array(
			'description' => __( 'Limit response to posts modified after a given ISO8601 compliant date.' ),
			'type'        => 'string',
			'format'      => 'date-time',
		);

		if ( post_type_supports( $this->post_type, 'author' ) ) {
			$query_params['author']         = array(
				'description' => __( 'Limit result set to posts assigned to specific authors.' ),
				'type'        => 'array',
				'items'       => array(
					'type' => 'integer',
				),
				'default'     => array(),
			);
			$query_params['author_exclude'] = array(
				'description' => __( 'Ensure result set excludes posts assigned to specific authors.' ),
				'type'        => 'array',
				'items'       => array(
					'type' => 'integer',
				),
				'default'     => array(),
			);
		}

		$query_params['before'] = array(
			'description' => __( 'Limit response to posts published before a given ISO8601 compliant date.' ),
			'type'        => 'string',
			'format'      => 'date-time',
		);

		$query_params['modified_before'] = array(
			'description' => __( 'Limit response to posts modified before a given ISO8601 compliant date.' ),
			'type'        => 'string',
			'format'      => 'date-time',
		);

		$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(),
		);

		if ( 'page' === $this->post_type || post_type_supports( $this->post_type, 'page-attributes' ) ) {
			$query_params['menu_order'] = array(
				'description' => __( 'Limit result set to posts with a specific menu_order value.' ),
				'type'        => 'integer',
			);
		}

		$query_params['search_semantics'] = array(
			'description' => __( 'How to interpret the search input.' ),
			'type'        => 'string',
			'enum'        => array( 'exact' ),
		);

		$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 post attribute.' ),
			'type'        => 'string',
			'default'     => 'date',
			'enum'        => array(
				'author',
				'date',
				'id',
				'include',
				'modified',
				'parent',
				'relevance',
				'slug',
				'include_slugs',
				'title',
			),
		);

		if ( 'page' === $this->post_type || post_type_supports( $this->post_type, 'page-attributes' ) ) {
			$query_params['orderby']['enum'][] = 'menu_order';
		}

		$post_type = get_post_type_object( $this->post_type );

		if ( $post_type->hierarchical || 'attachment' === $this->post_type ) {
			$query_params['parent']         = array(
				'description' => __( 'Limit result set to items with particular parent IDs.' ),
				'type'        => 'array',
				'items'       => array(
					'type' => 'integer',
				),
				'default'     => array(),
			);
			$query_params['parent_exclude'] = array(
				'description' => __( 'Limit result set to all items except those of a particular parent ID.' ),
				'type'        => 'array',
				'items'       => array(
					'type' => 'integer',
				),
				'default'     => array(),
			);
		}

		$query_params['search_columns'] = array(
			'default'     => array(),
			'description' => __( 'Array of column names to be searched.' ),
			'type'        => 'array',
			'items'       => array(
				'enum' => array( 'post_title', 'post_content', 'post_excerpt' ),
				'type' => 'string',
			),
		);

		$query_params['slug'] = array(
			'description' => __( 'Limit result set to posts with one or more specific slugs.' ),
			'type'        => 'array',
			'items'       => array(
				'type' => 'string',
			),
		);

		$query_params['status'] = array(
			'default'           => 'publish',
			'description'       => __( 'Limit result set to posts assigned one or more statuses.' ),
			'type'              => 'array',
			'items'             => array(
				'enum' => array_merge( array_keys( get_post_stati() ), array( 'any' ) ),
				'type' => 'string',
			),
			'sanitize_callback' => array( $this, 'sanitize_post_statuses' ),
		);

		$query_params = $this->prepare_taxonomy_limit_schema( $query_params );

		if ( 'post' === $this->post_type ) {
			$query_params['sticky'] = array(
				'description' => __( 'Limit result set to items that are sticky.' ),
				'type'        => 'boolean',
			);
		}

		if ( post_type_supports( $this->post_type, 'post-formats' ) ) {
			$query_params['format'] = array(
				'description' => __( 'Limit result set to items assigned one or more given formats.' ),
				'type'        => 'array',
				'uniqueItems' => true,
				'items'       => array(
					'enum' => array_values( get_post_format_slugs() ),
					'type' => 'string',
				),
			);
		}

		/**
		 * Filters collection parameters for the posts controller.
		 *
		 * The dynamic part of the filter `$this->post_type` refers to the post
		 * type slug for the controller.
		 *
		 * This filter registers the collection parameter, but does not map the
		 * collection parameter to an internal WP_Query parameter. Use the
		 * `rest_{$this->post_type}_query` filter to set WP_Query parameters.
		 *
		 * @since 4.7.0
		 *
		 * @param array        $query_params JSON Schema-formatted collection parameters.
		 * @param WP_Post_Type $post_type    Post type object.
		 */
		return apply_filters( "rest_{$this->post_type}_collection_params", $query_params, $post_type );
	}

	/**
	 * Sanitizes and validates the list of post statuses, including whether the
	 * user can query private statuses.
	 *
	 * @since 4.7.0
	 *
	 * @param string|array    $statuses  One or more post statuses.
	 * @param WP_REST_Request $request   Full details about the request.
	 * @param string          $parameter Additional parameter to pass to validation.
	 * @return array|WP_Error A list of valid statuses, otherwise WP_Error object.
	 */
	public function sanitize_post_statuses( $statuses, $request, $parameter ) {
		$statuses = wp_parse_slug_list( $statuses );

		// The default status is different in WP_REST_Attachments_Controller.
		$attributes     = $request->get_attributes();
		$default_status = $attributes['args']['status']['default'];

		foreach ( $statuses as $status ) {
			if ( $status === $default_status ) {
				continue;
			}

			$post_type_obj = get_post_type_object( $this->post_type );

			if ( current_user_can( $post_type_obj->cap->edit_posts ) || 'private' === $status && current_user_can( $post_type_obj->cap->read_private_posts ) ) {
				$result = rest_validate_request_arg( $status, $request, $parameter );
				if ( is_wp_error( $result ) ) {
					return $result;
				}
			} else {
				return new WP_Error(
					'rest_forbidden_status',
					__( 'Status is forbidden.' ),
					array( 'status' => rest_authorization_required_code() )
				);
			}
		}

		return $statuses;
	}

	/**
	 * Prepares the 'tax_query' for a collection of posts.
	 *
	 * @since 5.7.0
	 *
	 * @param array           $args    WP_Query arguments.
	 * @param WP_REST_Request $request Full details about the request.
	 * @return array Updated query arguments.
	 */
	private function prepare_tax_query( array $args, WP_REST_Request $request ) {
		$relation = $request['tax_relation'];

		if ( $relation ) {
			$args['tax_query'] = array( 'relation' => $relation );
		}

		$taxonomies = wp_list_filter(
			get_object_taxonomies( $this->post_type, 'objects' ),
			array( 'show_in_rest' => true )
		);

		foreach ( $taxonomies as $taxonomy ) {
			$base = ! empty( $taxonomy->rest_base ) ? $taxonomy->rest_base : $taxonomy->name;

			$tax_include = $request[ $base ];
			$tax_exclude = $request[ $base . '_exclude' ];

			if ( $tax_include ) {
				$terms            = array();
				$include_children = false;
				$operator         = 'IN';

				if ( rest_is_array( $tax_include ) ) {
					$terms = $tax_include;
				} elseif ( rest_is_object( $tax_include ) ) {
					$terms            = empty( $tax_include['terms'] ) ? array() : $tax_include['terms'];
					$include_children = ! empty( $tax_include['include_children'] );

					if ( isset( $tax_include['operator'] ) && 'AND' === $tax_include['operator'] ) {
						$operator = 'AND';
					}
				}

				if ( $terms ) {
					$args['tax_query'][] = array(
						'taxonomy'         => $taxonomy->name,
						'field'            => 'term_id',
						'terms'            => $terms,
						'include_children' => $include_children,
						'operator'         => $operator,
					);
				}
			}

			if ( $tax_exclude ) {
				$terms            = array();
				$include_children = false;

				if ( rest_is_array( $tax_exclude ) ) {
					$terms = $tax_exclude;
				} elseif ( rest_is_object( $tax_exclude ) ) {
					$terms            = empty( $tax_exclude['terms'] ) ? array() : $tax_exclude['terms'];
					$include_children = ! empty( $tax_exclude['include_children'] );
				}

				if ( $terms ) {
					$args['tax_query'][] = array(
						'taxonomy'         => $taxonomy->name,
						'field'            => 'term_id',
						'terms'            => $terms,
						'include_children' => $include_children,
						'operator'         => 'NOT IN',
					);
				}
			}
		}

		return $args;
	}

	/**
	 * Prepares the collection schema for including and excluding items by terms.
	 *
	 * @since 5.7.0
	 *
	 * @param array $query_params Collection schema.
	 * @return array Updated schema.
	 */
	private function prepare_taxonomy_limit_schema( array $query_params ) {
		$taxonomies = wp_list_filter( get_object_taxonomies( $this->post_type, 'objects' ), array( 'show_in_rest' => true ) );

		if ( ! $taxonomies ) {
			return $query_params;
		}

		$query_params['tax_relation'] = array(
			'description' => __( 'Limit result set based on relationship between multiple taxonomies.' ),
			'type'        => 'string',
			'enum'        => array( 'AND', 'OR' ),
		);

		$limit_schema = array(
			'type'  => array( 'object', 'array' ),
			'oneOf' => array(
				array(
					'title'       => __( 'Term ID List' ),
					'description' => __( 'Match terms with the listed IDs.' ),
					'type'        => 'array',
					'items'       => array(
						'type' => 'integer',
					),
				),
				array(
					'title'                => __( 'Term ID Taxonomy Query' ),
					'description'          => __( 'Perform an advanced term query.' ),
					'type'                 => 'object',
					'properties'           => array(
						'terms'            => array(
							'description' => __( 'Term IDs.' ),
							'type'        => 'array',
							'items'       => array(
								'type' => 'integer',
							),
							'default'     => array(),
						),
						'include_children' => array(
							'description' => __( 'Whether to include child terms in the terms limiting the result set.' ),
							'type'        => 'boolean',
							'default'     => false,
						),
					),
					'additionalProperties' => false,
				),
			),
		);

		$include_schema = array_merge(
			array(
				/* translators: %s: Taxonomy name. */
				'description' => __( 'Limit result set to items with specific terms assigned in the %s taxonomy.' ),
			),
			$limit_schema
		);
		// 'operator' is supported only for 'include' queries.
		$include_schema['oneOf'][1]['properties']['operator'] = array(
			'description' => __( 'Whether items must be assigned all or any of the specified terms.' ),
			'type'        => 'string',
			'enum'        => array( 'AND', 'OR' ),
			'default'     => 'OR',
		);

		$exclude_schema = array_merge(
			array(
				/* translators: %s: Taxonomy name. */
				'description' => __( 'Limit result set to items except those with specific terms assigned in the %s taxonomy.' ),
			),
			$limit_schema
		);

		foreach ( $taxonomies as $taxonomy ) {
			$base         = ! empty( $taxonomy->rest_base ) ? $taxonomy->rest_base : $taxonomy->name;
			$base_exclude = $base . '_exclude';

			$query_params[ $base ]                = $include_schema;
			$query_params[ $base ]['description'] = sprintf( $query_params[ $base ]['description'], $base );

			$query_params[ $base_exclude ]                = $exclude_schema;
			$query_params[ $base_exclude ]['description'] = sprintf( $query_params[ $base_exclude ]['description'], $base );

			if ( ! $taxonomy->hierarchical ) {
				unset( $query_params[ $base ]['oneOf'][1]['properties']['include_children'] );
				unset( $query_params[ $base_exclude ]['oneOf'][1]['properties']['include_children'] );
			}
		}

		return $query_params;
	}
}