deduplicateSessionBranches function

List<SessionMeta> deduplicateSessionBranches(List<SessionMeta> metas)

Deduplicate conversation branches within the same session.

When a session file has multiple leaf messages (from retries or branching), each branch shares the same root. This keeps only the branch with the most user messages (tie-break by longest duration) per session_id.

Implementation

List<SessionMeta> deduplicateSessionBranches(List<SessionMeta> metas) {
  final bestBySession = <String, SessionMeta>{};
  for (final meta in metas) {
    final existing = bestBySession[meta.sessionId];
    if (existing == null ||
        meta.userMessageCount > existing.userMessageCount ||
        (meta.userMessageCount == existing.userMessageCount &&
            meta.durationMinutes > existing.durationMinutes)) {
      bestBySession[meta.sessionId] = meta;
    }
  }
  return bestBySession.values.toList();
}