syntax = "proto3";
package eraftpb;

option go_package = "pkg/proto";

enum EntryType {
    EntryNormal = 0;
    EntryConfChange = 1;
}

// The entry is a type of change that needs to be applied. It contains two data fields.
// While the fields are built into the model; their usage is determined by the entry_type.
//
// For normal entries, the data field should contain the data change that should be applied.
// The context field can be used for any contextual data that might be relevant to the
// application of the data.
//
// For configuration changes, the data will contain the ConfChange message and the
// context will provide anything needed to assist the configuration change. The context
// if for the user to set and use in this case.
message Entry {
    EntryType entry_type = 1;
    uint64 term = 2;
    uint64 index = 3;
    bytes data = 4;
    bytes context = 6;

    // Deprecated! It is kept for backward compatibility.
    // TODO: remove it in the next major release.
    bool sync_log = 5;
}

message SnapshotMetadata {
    ConfState conf_state = 1;
    uint64 index = 2;
    uint64 term = 3;
}

message Snapshot {
    bytes data = 1;
    SnapshotMetadata metadata = 2;
}

enum MessageType {
    MsgHup = 0;
    MsgBeat = 1;
    MsgPropose = 2;
    MsgAppend = 3;
    MsgAppendResponse = 4;
    MsgRequestVote = 5;
    MsgRequestVoteResponse = 6;
    MsgSnapshot = 7;
    MsgHeartbeat = 8;
    MsgHeartbeatResponse = 9;
    MsgUnreachable = 10;
    MsgSnapStatus = 11;
    MsgCheckQuorum = 12;
    MsgTransferLeader = 13;
    MsgTimeoutNow = 14;
    MsgReadIndex = 15;
    MsgReadIndexResp = 16;
    MsgRequestPreVote = 17;
    MsgRequestPreVoteResponse = 18;
}

message Message {
    MessageType msg_type = 1;
    uint64 to = 2;
    uint64 from = 3;
    uint64 term = 4;
    uint64 log_term = 5;
    uint64 index = 6;
    repeated Entry entries = 7;
    uint64 commit = 8;
    Snapshot snapshot = 9;
    bool reject = 10;
    uint64 reject_hint = 11;
    bytes context = 12;
}

message HardState {
    uint64 term = 1;
    uint64 vote = 2;
    uint64 commit = 3;
}

message ConfState {
    repeated uint64 nodes = 1;
    repeated uint64 learners = 2;
}

enum ConfChangeType {
    AddNode    = 0;
    RemoveNode = 1;
    AddLearnerNode = 2;
}

message ConfChange {
    uint64 id = 1;
    ConfChangeType change_type = 2;
    uint64 node_id = 3;
    bytes context = 4;
}