// Copyright 2021 Lightbend Inc.

// gRPC interface for Akka Serverless Views.

syntax = "proto3";

package akkaserverless.component.view;

option go_package = "github.com/lightbend/akkaserverless-go-sdk/akkaserverless/view;view";
option java_package = "com.akkaserverless.protocol";

import "akkaserverless/component/component.proto";
import "google/protobuf/any.proto";

// Service that the SDK (in the user function) implements to make
// views available to the proxy.
//
// TODO: It is currently only implemented to support one request (ReceiveEvent)
// with one response (Upsert). The intention, and reason for full-duplex
// streaming, is that there should be able to have an interaction with two main
// types of operations, loads, and updates, and with each load there is an
// associated continuation, which in turn may return more operations, including
// more loads, and so on recursively.
service Views {
  rpc Handle(stream ViewStreamIn) returns (stream ViewStreamOut);
}

// Input message type for the gRPC stream in.
message ViewStreamIn {
  oneof message {
    ReceiveEvent receive = 1;
  }
}

message ReceiveEvent {
  string service_name = 1;
  string command_name = 2;
  google.protobuf.Any payload = 3;
  Metadata metadata = 4;
  string initial_table = 5;
  Key key = 6;
  Row by_subject_lookup_result = 7;
}

// Output message type for the gRPC stream out.
message ViewStreamOut {
  oneof message {
    Upsert upsert = 1;
  }
}

// to ignore an event and do nothing, use Upsert, but no/empty/null value for row
message Upsert {
  Row row = 1;
}

// Common messages

message Key {
  repeated KeyPart parts = 1;
}

message KeyPart {
  oneof part {
    string string_part = 1;
    bytes bytes_part = 2;
    int64 integer_part = 3;
    double float_part = 4;
  }
}

message Row {
  string index = 1;
  Key key = 2;
  google.protobuf.Any value = 3; // May be unset if a lookup found no row.
}