/**
 * Monotonic sequence number generator — shared by stream + buffer.
 *
 * Each chunk of output gets a unique, monotonically increasing seq number.
 * This lets clients resume a stream from a known position (IC-1 `lastSeq`).
 *
 * Owner: T-1.2
 */

export type SeqNum = number; // safe JS integer, starts at 1

/**
 * Per-session sequence counter.
 * Create one instance per session; share between the buffer writer and the
 * WebSocket broadcaster.
 */
export class SequenceCounter {
  private current: SeqNum = 0;

  /** Increment and return the next seq number. */
  next(): SeqNum {
    this.current += 1;
    return this.current;
  }

  /** Current value without incrementing. */
  peek(): SeqNum {
    return this.current;
  }

  /** Reset (e.g. after session restart). */
  reset(): void {
    this.current = 0;
  }
}