/*
 * @project      The CERN Tape Archive (CTA)
 * @copyright    Copyright © 2021-2022 CERN
 * @license      This program is free software, distributed under the terms of the GNU General Public
 *               Licence version 3 (GPL Version 3), copied verbatim in the file "COPYING". You can
 *               redistribute it and/or modify it under the terms of the GPL Version 3, or (at your
 *               option) any later version.
 *
 *               This program is distributed in the hope that it will be useful, but WITHOUT ANY
 *               WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 *               PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 *               In applying this licence, CERN does not waive the privileges and immunities
 *               granted to it by virtue of its status as an Intergovernmental Organization or
 *               submit itself to any jurisdiction.
 */

syntax = "proto3";

option java_multiple_files = true;
option java_package = "ch.cern.cta.rpc";
option optimize_for = CODE_SIZE;

package cta.frontend.rpc;

import "google/protobuf/empty.proto";
import "cta_admin.proto";
import "cta_eos.proto";
import "cta_frontend.proto";

/*
 * Requests sent to the CTA Frontend
 */

// gRPC Request for Archive/Retrieve/Delete/Cancel events
message SchedulerRequest {
  cta.eos.Notification md        = 1;    //< Metadata associated with this request
  string objectstore_id          = 2;    //< Address of the queued request in the SchedulerDB (objectstore),
                                         //< used to cancel a previous PREPARE request
  string client_version          = 3;    //< Client software version
  string client_protobuf_version = 4;    //< Client protobuf version
}

// gRPC Request for Admin commands
message AdminRequest {
  cta.admin.AdminCmd admincmd    = 1;    //< CTA Admin Command
  string client_version          = 2;    //< Version of cta-admin client
  string client_protobuf_version = 3;    //< Client protobuf version
}

/*
 * Metadata responses returned by the CTA Frontend
 */

message CreateResponse {
  uint64 archive_file_id = 1;    //< CTA-assigned unique file ID
}

message ArchiveResponse {
  string objectstore_id = 1;     //< Address of the queued request in the SchedulerDB (objectstore),
                                 //< used to cancel the request
}

message RetrieveResponse {
  string objectstore_id = 1;     //< Address of the queued request in the SchedulerDB (objectstore),
                                 //< used to cancel the request
}

message StreamResponse {
    oneof contents {
        cta.xrd.Response header = 1;
        cta.xrd.Data data = 2;
    }
}

// Negotiation
message KerberosAuthenticationRequest {
    bytes challenge = 1;                  //< GSS challenge
    string service_principal_name = 2;    //< KRB5 service principal name
};

message KerberosAuthenticationResponse {
    bytes challenge = 1;                  //< GSS challenge
    bool is_complete = 2;
    bytes token = 3;                      //< KRB5 token
    string error_msg = 4;
};

/*
 * gRPC request-response pairs
 */

service CtaRpc {
  // Generic request to give a migration path from EOS
  rpc GenericRequest (cta.xrd.Request) returns (cta.xrd.Response) {}

  // Specific request types
  rpc Create (SchedulerRequest) returns (CreateResponse) {}
  rpc Archive (SchedulerRequest) returns (ArchiveResponse) {}
  rpc Retrieve (SchedulerRequest) returns (RetrieveResponse) {}
  rpc Delete (SchedulerRequest) returns (google.protobuf.Empty) {}
  rpc CancelRetrieve (SchedulerRequest) returns (google.protobuf.Empty) {}

  // Admin commands
  rpc Admin (AdminRequest) returns (cta.xrd.Response) {}

  // Should possibly be replaced by AdminRequest "version" command
  rpc Version (google.protobuf.Empty) returns (cta.admin.Version) {}
}

service CtaRpcStream {
//  rpc Version (google.protobuf.Empty) returns (cta.admin.Version) {}
  rpc TapeLs (AdminRequest) returns (stream StreamResponse) {}
}

service Negotiation {
    rpc Negotiate (stream KerberosAuthenticationRequest) returns (stream KerberosAuthenticationResponse) {}
}