// Copyright 2026 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

syntax = "proto3";

package google.api;

import "google/protobuf/descriptor.proto";

option go_package = "google.golang.org/genproto/googleapis/api/annotations;annotations";
option java_multiple_files = true;
option java_outer_classname = "FieldInfoProto";
option java_package = "com.google.api";
option objc_class_prefix = "GAPI";

extend google.protobuf.FieldOptions {
  // Rich semantic descriptor of an API field beyond the basic typing.
  //
  // Examples:
  //
  //     string request_id = 1 [(google.api.field_info).format = UUID4];
  //     string old_ip_address = 2 [(google.api.field_info).format = IPV4];
  //     string new_ip_address = 3 [(google.api.field_info).format = IPV6];
  //     string actual_ip_address = 4 [
  //       (google.api.field_info).format = IPV4_OR_IPV6
  //     ];
  //     google.protobuf.Any generic_field = 5 [
  //       (google.api.field_info).referenced_types = {type_name: "ActualType"},
  //       (google.api.field_info).referenced_types = {type_name: "OtherType"},
  //     ];
  //     google.protobuf.Any generic_user_input = 5 [
  //       (google.api.field_info).referenced_types = {type_name: "*"},
  //     ];
  google.api.FieldInfo field_info = 291403980;
}

// Rich semantic information of an API field beyond basic typing.
message FieldInfo {
  // The standard format of a field value. The supported formats are all backed
  // by either an RFC defined by the IETF or a Google-defined AIP.
  enum Format {
    // Default, unspecified value.
    FORMAT_UNSPECIFIED = 0;

    // Universally Unique Identifier, version 4, value as defined by
    // https://datatracker.ietf.org/doc/html/rfc4122. The value may be
    // normalized to entirely lowercase letters. For example, the value
    // `F47AC10B-58CC-0372-8567-0E02B2C3D479` would be normalized to
    // `f47ac10b-58cc-0372-8567-0e02b2c3d479`.
    UUID4 = 1;

    // Internet Protocol v4 value as defined by [RFC
    // 791](https://datatracker.ietf.org/doc/html/rfc791). The value may be
    // condensed, with leading zeros in each octet stripped. For example,
    // `001.022.233.040` would be condensed to `1.22.233.40`.
    IPV4 = 2;

    // Internet Protocol v6 value as defined by [RFC
    // 2460](https://datatracker.ietf.org/doc/html/rfc2460). The value may be
    // normalized to entirely lowercase letters with zeros compressed, following
    // [RFC 5952](https://datatracker.ietf.org/doc/html/rfc5952). For example,
    // the value `2001:0DB8:0::0` would be normalized to `2001:db8::`.
    IPV6 = 3;

    // An IP address in either v4 or v6 format as described by the individual
    // values defined herein. See the comments on the IPV4 and IPV6 types for
    // allowed normalizations of each.
    IPV4_OR_IPV6 = 4;
  }

  // The standard format of a field value. This does not explicitly configure
  // any API consumer, just documents the API's format for the field it is
  // applied to.
  Format format = 1;

  // The type(s) that the annotated, generic field may represent.
  //
  // Currently, this must only be used on fields of type `google.protobuf.Any`.
  // Supporting other generic types may be considered in the future.
  repeated TypeReference referenced_types = 2;
}

// A reference to a message type, for use in [FieldInfo][google.api.FieldInfo].
message TypeReference {
  // The name of the type that the annotated, generic field may represent.
  // If the type is in the same protobuf package, the value can be the simple
  // message name e.g., `"MyMessage"`. Otherwise, the value must be the
  // fully-qualified message name e.g., `"google.library.v1.Book"`.
  //
  // If the type(s) are unknown to the service (e.g. the field accepts generic
  // user input), use the wildcard `"*"` to denote this behavior.
  //
  // See [AIP-202](https://google.aip.dev/202#type-references) for more details.
  string type_name = 1;
}
