/**
 * Environment variable helpers.
 */

/**
 * Parse a staleness window from an env var string (interpreted as hours).
 * Falls back to `defaultHours` when the value is missing, non-numeric,
 * non-finite, or <= 0 — preventing NaN from silently breaking staleness checks.
 */
export function parseStalenessHours(envVar: string | undefined, defaultHours: number): number {
  const parsed = parseInt(envVar ?? "", 10);
  return Number.isFinite(parsed) && parsed > 0 ? parsed : defaultHours;
}

/**
 * Returns today's date as YYYY-MM-DD using local wall-clock time with a 3 AM
 * switchover. Before 3 AM local time we still consider it "yesterday", so the
 * calendar doesn't flip to the next day at midnight while people are still out
 * at the park.
 *
 * Important: `new Date().toISOString()` returns UTC, which causes the date to
 * advance at 8 PM EDT (UTC-4) or 7 PM EST (UTC-5) — too early. This helper
 * corrects that by using local year/month/day components and rolling back one
 * day when the local hour is before 3.
 */
export function getTodayLocal(): string {
  const now = new Date();
  if (now.getHours() < 3) {
    now.setDate(now.getDate() - 1);
  }
  const y = now.getFullYear();
  const m = String(now.getMonth() + 1).padStart(2, "0");
  const d = String(now.getDate()).padStart(2, "0");
  return `${y}-${m}-${d}`;
}