import { TimestampPrefs, formatTimestamp } from './formatTimestamp';

/**
 * Builds a plain-text accessible label for a message row, used when the
 * visible sender/timestamp header is collapsed and therefore hidden from
 * assistive technology.
 *
 * @param sender - Sender display name (already resolved to a human string).
 * @param ts - Message origin timestamp in milliseconds.
 * @param prefs - The user's clock/date preferences.
 * @returns A label such as `Alice, 1 Jul 2026 14:30`.
 */
export const messageAriaLabel = (sender: string, ts: number, prefs: TimestampPrefs): string =>
  `${sender}, ${formatTimestamp(ts, prefs, 'dateTime')}`;