/*
 * SPDX-FileCopyrightText: 2023 Contributors to the Eclipse Foundation
 *
 * See the NOTICE file(s) distributed with this work for additional
 * information regarding copyright ownership.
 * 
 * This program and the accompanying materials are made available under
 * the terms of the Apache License Version 2.0 which is available at
 * https://www.apache.org/licenses/LICENSE-2.0
 *
 * SPDX-FileType: SOURCE
 * SPDX-License-Identifier: Apache-2.0
 */
syntax = "proto3";

package uprotocol.core.utwin.v2;

import "uprotocol/uoptions.proto";
import "uprotocol/v1/ustatus.proto";
import "uprotocol/v1/uri.proto";
import "uprotocol/v1/umessage.proto";

option java_package = "org.eclipse.uprotocol.core.utwin.v2";
option java_outer_classname = "UTwinProto";
option java_multiple_files = true;

// Enables generation of generic service attributes in C++
option cc_generic_services = true;

// uTwin Service interface definition
service uTwin {
  option (uprotocol.service_name) = "core.utwin"; // Service name
  option (uprotocol.service_version_major) = 2;
  option (uprotocol.service_version_minor) = 0;
  option (uprotocol.service_id) = 3;

  // A uE calls this API to retrieve the last uMessages for a given set of topics.<br>
  // What is returned is a list of MessageResponse with the status for message retrieval
  // and the event itself if uTwin was able to fetch it. uTwin will also return
  // status for those messages that it was unable to fetch (i.e. due to NOT_FOUND
  // or PERMISSION_DENIED.<br>
  rpc GetLastMessages(GetLastMessagesRequest) returns (GetLastMessagesResponse) {
    option (uprotocol.method_id) = 1;
  }
}


// Response that contains the status and message per topic
message MessageResponse {
  // Topic that was requested to be fetched
  uprotocol.v1.UUri topic = 1;

  // Status (success or not) when fetching the last event for said topic
  uprotocol.v1.UStatus status = 2;

  // message when the topic has been fetched successfully, otherwise empty
  uprotocol.v1.UMessage message = 3;
}

// The request message for the GetLastMessage operation.
message GetLastMessagesRequest {
  // The topics to get the last message for
  uprotocol.v1.UUriBatch topics = 1;
}

// Message returned by the rpc GetLastMessages.
message GetLastMessagesResponse {
  // List of one or more messages and the results for fetching the message per topic
  repeated MessageResponse responses = 2;
}