Function meta

telemetry-dashboard/src/api.ts:223–250

* What the picker anchors on. The dashboard asks for this first and ends every * default range on `latest_day`, because the nightly cron has not rolled up * today yet — anchoring on the wall clock would put a phantom zero on the right * edge of every line chart.

(env: Env)

 * edge of every line chart.
 */
async function meta(env: Env): Promise<ApiResult> {
  const row = await env.DB.prepare(
    `SELECT (SELECT max(day) FROM daily_event_counts) AS latest_rollup_day,
            (SELECT min(day) FROM daily_event_counts) AS earliest_rollup_day,
            (SELECT max(day) FROM machine_days)       AS latest_active_day,
            (SELECT min(day) FROM machine_days)       AS earliest_active_day,
            (SELECT min(day) FROM events)             AS earliest_raw_day,
            (SELECT max(day) FROM events)             AS latest_raw_day`,
  ).first<MetaRow>();

  const latest = row?.latest_rollup_day ?? row?.latest_active_day ?? null;
  const earliest = row?.earliest_rollup_day ?? row?.earliest_active_day ?? null;
  return {
    body: {
      latest_day: latest,
      earliest_day: earliest,
      latest_rollup_day: row?.latest_rollup_day ?? null,
      latest_active_day: row?.latest_active_day ?? null,
      /** Below this day the activation funnel is blind — raw events are purged. */
      earliest_raw_day: row?.earliest_raw_day ?? null,
      latest_raw_day: row?.latest_raw_day ?? null,
      max_range_days: MAX_RANGE_DAYS,
      retention_days: RETENTION_DAYS,
      generated_at: new Date().toISOString(),
    },
    cacheControl: CACHE_CONTROL,
  };
}

// ---------------------------------------------------------------------------
// /api/summary — the big numbers