const DEFAULT_COMMAND_DEADLINE_MS = 60_000;

export function classifyExecuteCommandExpiry(event, { now = Date.now() } = {}) {
  const payload = event?.payload || {};
  const observedAtMs = parseTimestamp(
    event?.observed_at
    || payload.quote_observed_at
    || payload.decision_at
    || event?.ingested_at,
  );
  const deadlineMs = parseDeadlineMs(payload.min_deadline_ms);

  if (!Number.isFinite(observedAtMs)) {
    return {
      expired: true,
      reason: 'command_timestamp_missing',
      age_ms: null,
      deadline_ms: deadlineMs,
      deadline_at: null,
    };
  }

  if (!Number.isFinite(deadlineMs) || deadlineMs <= 0) {
    return {
      expired: true,
      reason: 'command_deadline_invalid',
      age_ms: Math.max(0, now - observedAtMs),
      deadline_ms: null,
      deadline_at: null,
    };
  }

  const deadlineAtMs = observedAtMs + deadlineMs;
  const ageMs = Math.max(0, now - observedAtMs);
  return {
    expired: now > deadlineAtMs,
    reason: now > deadlineAtMs ? 'command_deadline_elapsed' : null,
    age_ms: ageMs,
    deadline_ms: deadlineMs,
    deadline_at: new Date(deadlineAtMs).toISOString(),
  };
}

function parseDeadlineMs(value) {
  if (value == null || value === '') return DEFAULT_COMMAND_DEADLINE_MS;
  const parsed = Number(value);
  return Number.isFinite(parsed) ? parsed : Number.NaN;
}

function parseTimestamp(value) {
  if (!value) return Number.NaN;
  const parsed = Date.parse(value);
  return Number.isFinite(parsed) ? parsed : Number.NaN;
}