/* -------------------------------------------------------------------
**
** machi.proto: Protocol Buffers definition for Machi
**
** Copyright (c) 2014-2015 Basho Technologies, Inc.  All Rights Reserved.
**
** This file is provided to you 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.
**
** -------------------------------------------------------------------
*/

/*
** Revision: 0.1
*/

// Java package specifiers
option java_package = "com.basho.machi.protobuf";
option java_outer_classname = "MachiPB";

//////////////////////////////////////////
//
// enums
//
//////////////////////////////////////////

enum MpbGeneralStatusCode {
     OK = 0;
     BAD_ARG = 1;
     WEDGED = 2;
     BAD_CHECKSUM = 3;
}

// Must match with machi.hrl's values!
enum MpbCSumType {
     CSUM_TAG_NONE = 0;
     CSUM_TAG_CLIENT_GEN = 1;
     CSUM_TAG_SERVER_GEN = 2;
     CSUM_TAG_SERVER_REGEN = 3;
}

//////////////////////////////////////////
//
// basic data types
//
//////////////////////////////////////////

// chunk_pos() type
message MpbChunkPos {
    required uint64 offset = 1;
    required uint64 chunk_size = 2;
    required string file_name = 3;
}

// chunk_csum() type
message MpbChunkCSum {
    required MpbCSumType type = 1;
    required bytes csum = 2;
}

// epoch_id() type
message MpbEpochId {
    required uint32 epoch_num = 1;
    required MpbChunkCSum epoch_csum = 2;
}

// Error response - may be generated for any Req
message MpbErrorResp {
    required string errmsg = 1;
    required uint32 errcode = 2;
}

//////////////////////////////////////////
//
// requests & responses
//
//////////////////////////////////////////

// ping() request & response

message MpbEchoReq {
    optional string message = 1;
}

message MpbEchoResp {
    optional string message = 1;
}

// Authentication request & response

message MpbAuthReq {
    required bytes user = 1;
    required bytes password = 2;
}

message MpbAuthResp {
    required uint32 code = 1;
    // TODO: not implemented yet
}

// append_chunk() request & response

message MpbAppendChunkReq {
    required string prefix = 1;
    optional bytes placement_key = 2;
    required bytes chunk = 3;
    optional uint32 chunk_extra = 4;
}

message MpbAppendChunkResp {
    required MpbGeneralStatusCode status = 1;
    optional MpbChunkPos chunk_pos = 2;
    optional MbpGeneralError = 3;
}

//////////////////////////////////////////
//
// request & response wrapper
//
//////////////////////////////////////////

message MpbRequest_v1 {
    // TODO: If we wish to support pipelined requests sometime in the
    // future, this is the placeholder to do it.
    required bytes req_id = 1;

    // The client should only define one request message.  If the client
    // includes multiple requests here, the server may pick/choose an
    // arbitrary one.
    // NOTE: The erlang protobuffs compiler doesn't support 'oneof'.
    //       But 'oneof' appears to be a very tiny memory optimization
    //       that not all languages might care about?  (Erlang doesn't)
    optional MpbEchoReq echo = 10;
    optional MpbAuthReq auth = 11;
    optional MpbAppendChunkReq append_chunk = 12;
}

message MpbResponse_v1 {
    // TODO: If we wish to support pipelined requests sometime in the
    // future, this is the placeholder to do it.
    required bytes req_id = 1;

    // The server will define only one of the optional responses below.

    // Generic error response, typically used when something quite
    // bad/unexpected happened within the server.
    // Clients should always check this response and, if defined,
    // ignroe any request-specific response at codes 10+.
    optional MpbErrorResp = 2;

    // Specific responses.
    optional MpbEchoResp echo = 10;
    optional MpbAuthResp auth = 11;
    optional MpbAppendChunkResp append_chunk = 12;
}