/**
 * Flag definition sync API
 *
 * This proto defines a simple API to synchronize a feature flag definition.
 * It supports establishing a stream for getting notifications about changes in a flag definition.
 */
syntax = "proto3";

package flagd.sync.v1;

import "google/protobuf/struct.proto";

option csharp_namespace = "OpenFeature.Flagd.Grpc.Sync";
option go_package = "flagd/sync/v1";
option java_package = "dev.openfeature.flagd.grpc.sync";
option php_namespace = "OpenFeature\\Providers\\Flagd\\Schema\\Grpc\\Sync";
option ruby_package = "OpenFeature::Flagd::Provider::Grpc::Sync";

// SyncFlagsRequest is the request initiating the server-streaming rpc.
// Implementations of Flagd providers and Flagd itself send this request, acting as the client.
message SyncFlagsRequest {
  // Optional: A unique identifier for flagd(grpc client) initiating the request. The server implementations may
  // utilize this identifier to uniquely identify, validate(ex:- enforce authentication/authorization) and filter
  // flag configurations that it can expose to this request. This field is intended to be optional. However server
  // implementations may enforce it.
  //    ex:- provider_id: flagd-weatherapp-sidecar
  string provider_id = 1;

  // Optional: A selector for the flag configuration request. The server implementation may utilize this to select
  // flag configurations from a collection, select the source of the flag or combine this to any desired underlying
  // filtering mechanism.
  //    ex:- selector: 'source=database,app=weatherapp'
  string selector = 2;
}

// SyncFlagsResponse is the server response containing feature flag configurations and the state
message SyncFlagsResponse {
  // flagd feature flag configuration. Must be validated to schema - https://raw.githubusercontent.com/open-feature/schemas/main/json/flagd-definitions.json
  string flag_configuration = 1;
}

// FetchAllFlagsRequest is the request to fetch all flags. Clients send this request as the client in order to resync their internal state
message FetchAllFlagsRequest {
  // Optional: A unique identifier for clients initiating the request. The server implementations may
  // utilize this identifier to uniquely identify, validate(ex:- enforce authentication/authorization) and filter
  // flag configurations that it can expose to this request. This field is intended to be optional. However server
  // implementations may enforce it.
  //    ex:- provider_id: flagd-weatherapp-sidecar
  string provider_id = 1;

  // Optional: A selector for the flag configuration request. The server implementation may utilize this to select
  // flag configurations from a collection, select the source of the flag or combine this to any desired underlying
  // filtering mechanism.
  //    ex:- selector: 'source=database,app=weatherapp'
  string selector = 2;
}

// FetchAllFlagsResponse is the server response containing feature flag configurations
message FetchAllFlagsResponse {
  // flagd feature flag configuration. Must be validated to schema - https://raw.githubusercontent.com/open-feature/schemas/main/json/flagd-definitions.json
  string flag_configuration = 1;
}

// GetMetadataRequest is the request for retrieving metadata from the sync service
message GetMetadataRequest {}

// GetMetadataResponse contains metadata from the sync service
message GetMetadataResponse {
  reserved 1; // old key/value metadata impl
  google.protobuf.Struct metadata = 2;
}

// FlagService implements a server streaming to provide realtime flag configurations
service FlagSyncService {
  rpc SyncFlags(SyncFlagsRequest) returns (stream SyncFlagsResponse) {}
  rpc FetchAllFlags(FetchAllFlagsRequest) returns (FetchAllFlagsResponse) {}
  rpc GetMetadata(GetMetadataRequest) returns (GetMetadataResponse) {}
}