syntax = "proto3";

package photon.imessage.v1;

import "photon/imessage/v1/chat_types.proto";
import "photon/imessage/v1/group_types.proto";
import "photon/imessage/v1/message_types.proto";
import "photon/imessage/v1/poll_types.proto";
import "photon/imessage/v1/streaming.proto";

option swift_prefix = "PIMsg_";


// ---------------------------------------------------------------------------
// Service
// ---------------------------------------------------------------------------

// Unified finite replay across every durable event domain:
// messages, group state, polls, and chats.
//
// Drains everything newer than `after_sequence` and terminates with
// `CatchUpEventsComplete`, after which the caller hands off to the live
// `Subscribe*` streams without gaps.
//
// All `sequence` values returned here share the same global event log
// as `SubscribeMessageEvents`, `SubscribeGroupEvents`, `SubscribePollEvents`,
// and `SubscribeChatEvents`.
service EventService {

  rpc CatchUpEvents(CatchUpEventsRequest) returns (stream CatchUpEventsResponse);

}


// ---------------------------------------------------------------------------
// Catch-up
// ---------------------------------------------------------------------------

message CatchUpEventsRequest {

  // Resume cursor; absent = replay every event the server still holds.
  optional uint64 after_sequence = 1;

}


// Terminal frame.
//
// `head_sequence` is the fixed global head captured when this catch-up
// started. This stream replays every event with:
//
//   after_sequence < sequence <= head_sequence
//
// Then it terminates. The caller resumes live by passing `head_sequence`
// as `after_sequence` to a `Subscribe*` stream.
message CatchUpEventsComplete {

  uint64 head_sequence = 1;

}


message CatchUpEventsResponse {

  // Monotonic global sequence; absent only on the terminal `complete`
  // frame.
  optional uint64 sequence = 1;

  oneof payload {

    MessageChangeEvent message_changed = 10;

    GroupChangeEvent group_changed = 11;

    PollChangeEvent poll_changed = 12;

    ChatChangeEvent chat_changed = 13;

    CatchUpEventsComplete complete = 20;

    Heartbeat heartbeat = 99;

  }

}