/**
 * Formats a timestamp as relative time (e.g., "1s ago", "5m ago", "2h ago")
 * @param timestamp - The timestamp to format (Date object or number in milliseconds)
 * @param currentTime - Current time in milliseconds (defaults to Date.now())
 * @returns Formatted relative time string
 */
export function formatRelativeTime(
  timestamp: Date | number,
  currentTime: number = Date.now()
): string {
  const timestampMs =
    timestamp instanceof Date ? timestamp.getTime() : timestamp;
  const seconds = Math.floor((currentTime - timestampMs) / 1000);

  // Handle edge cases
  if (seconds < 0) {
    return "just now";
  }

  if (seconds < 60) {
    return seconds === 0 ? "just now" : `${seconds}s ago`;
  }

  const minutes = Math.floor(seconds / 60);
  if (minutes < 60) {
    return `${minutes}m ago`;
  }

  const hours = Math.floor(minutes / 60);
  if (hours < 24) {
    return `${hours}h ago`;
  }

  const days = Math.floor(hours / 24);
  return `${days}d ago`;
}