$memo;
}

/**
 * Parses the "_embed" parameter into the list of resources to embed.
 *
 * @since 5.4.0
 *
 * @param string|array $embed Raw "_embed" parameter value.
 * @return true|string[] Either true to embed all embeds, or a list of relations to embed.
 */
function rest_parse_embed_param( $embed ) {
	if ( ! $embed || 'true' === $embed || '1' === $embed ) {
		return true;
	}

	$rels = wp_parse_list( $embed );

	if ( ! $rels ) {
		return true;
	}

	return $rels;
}

/**
 * Filters the response to remove any fields not available in the given context.
 *
 * @since 5.5.0
 * @since 5.6.0 Support the "patternProperties" keyword for objects.
 *              Support the "anyOf" and "oneOf" keywords.
 *
 * @param array|object $data    The response data to modify.
 * @param array        $schema  The schema for the endpoint used to filter the response.
 * @param string       $context The requested context.
 * @return array|object The filtered response data.
 */
function rest_filter_response_by_context( $data, $schema, $context ) {
	if ( isset( $schema['anyOf'] ) ) {
		$matching_schema = rest_find_any_matching_schema( $data, $schema, '' );
		if ( ! is_wp_error( $matching_schema ) ) {
			if ( ! isset( $schema['type'] ) ) {
				$schema['type'] = $matching_schema['type'];
			}

			$data = rest_filter_response_by_context( $data, $matching_schema, $context );
		}
	}

	if ( isset( $schema['oneOf'] ) ) {
		$matching_schema = rest_find_one_matching_schema( $data, $schema, '', true );
		if ( ! is_wp_error( $matching_schema ) ) {
			if ( ! isset( $schema['type'] ) ) {
				$schema['type'] = $matching_schema['type'];
			}

			$data = rest_filter_response_by_context( $data, $matching_schema, $context );
		}
	}

	if ( ! is_array( $data ) && ! is_object( $data ) ) {
		return $data;
	}

	if ( isset( $schema['type'] ) ) {
		$type = $schema['type'];
	} elseif ( isset( $schema['properties'] ) ) {
		$type = 'object'; // Back compat if a developer accidentally omitted the type.
	} else {
		return $data;
	}

	$is_array_type  = 'array' === $type || ( is_array( $type ) && in_array( 'array', $type, true ) );
	$is_object_type = 'object' === $type || ( is_array( $type ) && in_array( 'object', $type, true ) );

	if ( $is_array_type && $is_object_type ) {
		if ( rest_is_array( $data ) ) {
			$is_object_type = false;
		} else {
			$is_array_type = false;
		}
	}

	$has_additional_properties = $is_object_type && isset( $schema['additionalProperties'] ) && is_array( $schema['additionalProperties'] );

	foreach ( $data as $key => $value ) {
		$check = array();

		if ( $is_array_type ) {
			$check = isset( $schema['items'] ) ? $schema['items'] : array();
		} elseif ( $is_object_type ) {
			if ( isset( $schema['properties'][ $key ] ) ) {
				$check = $schema['properties'][ $key ];
			} else {
				$pattern_property_schema = rest_find_matching_pattern_property_schema( $key, $schema );
				if ( null !== $pattern_property_schema ) {
					$check = $pattern_property_schema;
				} elseif ( $has_additional_properties ) {
					$check = $schema['additionalProperties'];
				}
			}
		}

		if ( ! isset( $check['context'] ) ) {
			continue;
		}

		if ( ! in_array( $context, $check['context'], true ) ) {
			if ( $is_array_type ) {
				// All array items share schema, so there's no need to check each one.
				$data = array();
				break;
			}

			if ( is_object( $data ) ) {
				unset( $data->$key );
			} else {
				unset( $data[ $key ] );
			}
		} elseif ( is_array( $value ) || is_object( $value ) ) {
			$new_value = rest_filter_response_by_context( $value, $check, $context );

			if ( is_object( $data ) ) {
				$data->$key = $new_value;
			} else {
				$data[ $key ] = $new_value;
			}
		}
	}

	return $data;
}

/**
 * Sets the "additionalProperties" to false by default for all object definitions in the schema.
 *
 * @since 5.5.0
 * @since 5.6.0 Support the "patternProperties" keyword.
 *
 * @param array $schema The schema to modify.
 * @return array The modified schema.
 */
function rest_default_additional_properties_to_false( $schema ) {
	$type = (array) $schema['type'];

	if ( in_array( 'object', $type, true ) ) {
		if ( isset( $schema['properties'] ) ) {
			foreach ( $schema['properties'] as $key => $child_schema ) {
				$schema['properties'][ $key ] = rest_default_additional_properties_to_false( $child_schema );
			}
		}

		if ( isset( $schema['patternProperties'] ) ) {
			foreach ( $schema['patternProperties'] as $key => $child_schema ) {
				$schema['patternProperties'][ $key ] = rest_default_additional_properties_to_false( $child_schema );
			}
		}

		if ( ! isset( $schema['additionalProperties'] ) ) {
			$schema['additionalProperties'] = false;
		}
	}

	if ( in_array( 'array', $type, true ) ) {
		if ( isset( $schema['items'] ) ) {
			$schema['items'] = rest_default_additional_properties_to_false( $schema['items'] );
		}
	}

	return $schema;
}

/**
 * Gets the REST API route for a post.
 *
 * @since 5.5.0
 *
 * @param int|WP_Post $post Post ID or post object.
 * @return string The route path with a leading slash for the given post, or an empty string if there is not a route.
 */
function rest_get_route_for_post( $post ) {
	$post = get_post( $post );

	if ( ! $post instanceof WP_Post ) {
		return '';
	}

	$post_type = get_post_type_object( $post->post_type );
	if ( ! $post_type ) {
		return '';
	}

	$controller = $post_type->get_rest_controller();
	if ( ! $controller ) {
		return '';
	}

	$route = '';

	// The only two controllers that we can detect are the Attachments and Posts controllers.
	if ( in_array( get_class( $controller ), array( 'WP_REST_Attachments_Controller', 'WP_REST_Posts_Controller' ), true ) ) {
		$namespace = 'wp/v2';
		$rest_base = ! empty( $post_type->rest_base ) ? $post_type->rest_base : $post_type->name;
		$route     = sprintf( '/%s/%s/%d', $namespace, $rest_base, $post->ID );
	}

	/**
	 * Filters the REST API route for a post.
	 *
	 * @since 5.5.0
	 *
	 * @param string  $route The route path.
	 * @param WP_Post $post  The post object.
	 */
	return apply_filters( 'rest_route_for_post', $route, $post );
}

/**
 * Gets the REST API route for a term.
 *
 * @since 5.5.0
 *
 * @param int|WP_Term $term Term ID or term object.
 * @return string The route path with a leading slash for the given term, or an empty string if there is not a route.
 */
function rest_get_route_for_term( $term ) {
	$term = get_term( $term );

	if ( ! $term instanceof WP_Term ) {
		return '';
	}

	$taxonomy = get_taxonomy( $term->taxonomy );
	if ( ! $taxonomy ) {
		return '';
	}

	$controller = $taxonomy->get_rest_controller();
	if ( ! $controller ) {
		return '';
	}

	$route = '';

	// The only controller that works is the Terms controller.
	if ( $controller instanceof WP_REST_Terms_Controller ) {
		$namespace = 'wp/v2';
		$rest_base = ! empty( $taxonomy->rest_base ) ? $taxonomy->rest_base : $taxonomy->name;
		$route     = sprintf( '/%s/%s/%d', $namespace, $rest_base, $term->term_id );
	}

	/**
	 * Filters the REST API route for a term.
	 *
	 * @since 5.5.0
	 *
	 * @param string  $route The route path.
	 * @param WP_Term $term  The term object.
	 */
	return apply_filters( 'rest_route_for_term', $route, $term );
}

/**
 * Gets the REST route for the currently queried object.
 *
 * @since 5.5.0
 *
 * @return string The REST route of the resource, or an empty string if no resource identified.
 */
function rest_get_queried_resource_route() {
	if ( is_singular() ) {
		$route = rest_get_route_for_post( get_queried_object() );
	} elseif ( is_category() || is_tag() || is_tax() ) {
		$route = rest_get_route_for_term( get_queried_object() );
	} elseif ( is_author() ) {
		$route = '/wp/v2/users/' . get_queried_object_id();
	} else {
		$route = '';
	}

	/**
	 * Filters the REST route for the currently queried object.
	 *
	 * @since 5.5.0
	 *
	 * @param string $link The route with a leading slash, or an empty string.
	 */
	return apply_filters( 'rest_queried_resource_route', $route );
}

/**
 * Retrieves an array of endpoint arguments from the item schema and endpoint method.
 *
 * @since 5.6.0
 *
 * @param array  $schema The full JSON schema for the endpoint.
 * @param string $method Optional. HTTP method of the endpoint. The arguments for `CREATABLE` endpoints are
 *                       checked for required values and may fall-back to a given default, this is not done
 *                       on `EDITABLE` endpoints. Default WP_REST_Server::CREATABLE.
 * @return array The endpoint arguments.
 */
function rest_get_endpoint_args_for_schema( $schema, $method = WP_REST_Server::CREATABLE ) {

	$schema_properties       = ! empty( $schema['properties'] ) ? $schema['properties'] : array();
	$endpoint_args           = array();
	$valid_schema_properties = rest_get_allowed_schema_keywords();
	$valid_schema_properties = array_diff( $valid_schema_properties, array( 'default', 'required' ) );

	foreach ( $schema_properties as $field_id => $params ) {

		// Arguments specified as `readonly` are not allowed to be set.
		if ( ! empty( $params['readonly'] ) ) {
			continue;
		}

		$endpoint_args[ $field_id ] = array(
			'validate_callback' => 'rest_validate_request_arg',
			'sanitize_callback' => 'rest_sanitize_request_arg',
		);

		if ( WP_REST_Server::CREATABLE === $method && isset( $params['default'] ) ) {
			$endpoint_args[ $field_id ]['default'] = $params['default'];
		}

		if ( WP_REST_Server::CREATABLE === $method && ! empty( $params['required'] ) ) {
			$endpoint_args[ $field_id ]['required'] = true;
		}

		foreach ( $valid_schema_properties as $schema_prop ) {
			if ( isset( $params[ $schema_prop ] ) ) {
				$endpoint_args[ $field_id ][ $schema_prop ] = $params[ $schema_prop ];
			}
		}

		// Merge in any options provided by the schema property.
		if ( isset( $params['arg_options'] ) ) {

			// Only use required / default from arg_options on CREATABLE endpoints.
			if ( WP_REST_Server::CREATABLE !== $method ) {
				$params['arg_options'] = array_diff_key(
					$params['arg_options'],
					array(
						'required' => '',
						'default'  => '',
					)
				);
			}

			$endpoint_args[ $field_id ] = array_merge( $endpoint_args[ $field_id ], $params['arg_options'] );
		}
	}

	return $endpoint_args;
}


/**
 * Converts an error to a response object.
 *
 * This iterates over all error codes and messages to change it into a flat
 * array. This enables simpler client behaviour, as it is represented as a
 * list in JSON rather than an object/map.
 *
 * @since 5.7.0
 *
 * @param WP_Error $error WP_Error instance.
 *
 * @return WP_REST_Response List of associative arrays with code and message keys.
 */
function rest_convert_error_to_response( $error ) {
	$status = array_reduce(
		$error->get_all_error_data(),
		function ( $status, $error_data ) {
			return is_array( $error_data ) && isset( $error_data['status'] ) ? $error_data['status'] : $status;
		},
		500
	);

	$errors = array();

	foreach ( (array) $error->errors as $code => $messages ) {
		$all_data  = $error->get_all_error_data( $code );
		$last_data = array_pop( $all_data );

		foreach ( (array) $messages as $message ) {
			$formatted = array(
				'code'    => $code,
				'message' => $message,
				'data'    => $last_data,
			);

			if ( $all_data ) {
				$formatted['additional_data'] = $all_data;
			}

			$errors[] = $formatted;
		}
	}

	$data = $errors[0];
	if ( count( $errors ) > 1 ) {
		// Remove the primary error.
		array_shift( $errors );
		$data['additional_errors'] = $errors;
	}

	return new WP_REST_Response( $data, $status );
}