syntax = "proto3";

package chatto.api.v1;

import "buf/validate/validate.proto";
import "google/protobuf/timestamp.proto";

// Request to mark a room timeline as read.
message MarkRoomAsReadRequest {
  // Required. Room whose timeline should be marked read.
  string room_id = 1 [(buf.validate.field).string.min_len = 1];
  // Highest room event ID the current user has read. When set, the event must
  // exist as a root event in the room timeline. Leave empty to mark through the
  // room's current latest root event.
  string up_to_event_id = 2;
}

// Result of marking a room timeline as read.
//
// Clients can use the previous timestamp to place a local New messages
// separator. Notification policy controls room Badge attention separately.
message MarkRoomAsReadResponse {
  // New room read timestamp stored for the current user.
  google.protobuf.Timestamp last_read_at = 1;
  // Previous room read timestamp, when one existed.
  google.protobuf.Timestamp previous_last_read_at = 2;
}

// Request to mark a message thread as read.
message MarkThreadAsReadRequest {
  // Required. Room containing the thread.
  string room_id = 1 [(buf.validate.field).string.min_len = 1];
  // Required. Event ID of the root message for the thread.
  string thread_root_event_id = 2 [(buf.validate.field).string.min_len = 1];
  // Highest thread event ID the current user has read. The event should belong
  // to the thread identified by thread_root_event_id.
  string up_to_event_id = 3;
}

// Result of marking a message thread as read.
message MarkThreadAsReadResponse {
  reserved "previous_read_at";

  // Previous thread read timestamp, when one existed.
  google.protobuf.Timestamp previous_last_read_at = 1;
  // Resulting thread read timestamp. A stale request retains the newer marker.
  // Absent when no marker exists.
  google.protobuf.Timestamp last_read_at = 2;
}

// Current stored read position. Its event can later be retracted. The timestamp
// is absent if the event can no longer be resolved. This is not Badge attention.
message ReadMarker {
  // Last-read event ID, to locate the boundary in a timeline.
  string last_read_event_id = 1;
  // Creation time of the last-read event, when available.
  google.protobuf.Timestamp last_read_at = 2;
}

// Current viewer's stored room read state.
message RoomReadState {
  // Room ID.
  string room_id = 1;
  // Absent when no non-empty marker has been stored. Reading never initializes it.
  ReadMarker marker = 2;
}

// Current viewer's stored thread read state.
message ThreadReadState {
  // Room ID.
  string room_id = 1;
  // Root message ID.
  string thread_root_event_id = 2;
  // Absent when no non-empty marker has been stored. Reading never advances it.
  ReadMarker marker = 3;
}

// Request current room read state without changing it.
message GetRoomReadStateRequest {
  // Room ID.
  string room_id = 1 [(buf.validate.field).string.min_len = 1];
}
// Current room read state, including an absent marker when none is stored.
message GetRoomReadStateResponse {
  // State for the requested room and viewer.
  RoomReadState state = 1;
}
// Request room read states. Duplicates are removed in first-seen order.
message BatchGetRoomReadStatesRequest {
  // Up to 100 room IDs. Missing or inaccessible rooms are omitted.
  repeated string room_ids = 1 [(buf.validate.field).repeated = {
    min_items: 1, max_items: 100, items: {string: {min_len: 1}}
  }];
}
// Accessible room read states in first-seen request order.
message BatchGetRoomReadStatesResponse {
  // States for the current viewer. An absent marker does not omit the state.
  repeated RoomReadState states = 1;
}
// Request current thread read state without changing it.
message GetThreadReadStateRequest {
  // Room ID.
  string room_id = 1 [(buf.validate.field).string.min_len = 1];
  // Root message ID.
  string thread_root_event_id = 2 [(buf.validate.field).string.min_len = 1];
}
// Current thread read state.
message GetThreadReadStateResponse {
  // State for the requested thread and viewer.
  ThreadReadState state = 1;
}
// Request thread read states. Duplicates are removed in first-seen order.
message BatchGetThreadReadStatesRequest {
  // Up to 100 room/thread targets. Missing or inaccessible targets are omitted.
  repeated ThreadReadStateTarget targets = 1 [(buf.validate.field).repeated = {min_items: 1, max_items: 100}];
}
// Accessible thread read states in first-seen request order.
message BatchGetThreadReadStatesResponse {
  // States for the current viewer. An absent marker does not omit the state.
  repeated ThreadReadState states = 1;
}

// Room and root identity for one thread read state.
message ThreadReadStateTarget {
  // Room ID.
  string room_id = 1 [(buf.validate.field).string.min_len = 1];
  // Root message ID.
  string thread_root_event_id = 2 [(buf.validate.field).string.min_len = 1];
}