import { createHash } from "node:crypto";

/**
 * Derive a short, non-reversible fingerprint of a Telegram bot token suitable
 * for diagnostic logs and persisted-state identity checks. Two tokens for the
 * same bot (e.g. after BotFather `/revoke`) share the same bot id but produce
 * different fingerprints, which lets callers detect rotation without storing
 * the token secret on disk.
 */
export function fingerprintTelegramBotToken(token: string): string {
  return createHash("sha256").update(token).digest("hex").slice(0, 16);
}