Optimize terminal batching and cache guards

frontend/components/dashboard/ScanTerminalDashboard.tsx

@@ -77,6 +77,8 @@ const TrainingDashboard = dynamic(
   },
 );
 
+const ONLINE_USERS_REFRESH_MS = 5 * 60_000;
+
 function createEmptyAccess(loading = true): ProAccessState {
   return {
     loading,
@@ -425,14 +427,22 @@ function PolyWeatherTerminal({
 
   useEffect(() => {
     const fetchOnline = () => {
+      if (typeof document !== "undefined" && document.visibilityState === "hidden") return;
       fetch("/api/ops/online-users", { headers: { Accept: "application/json" } })
         .then((r) => (r.ok ? r.json() : null))
         .then((d) => { if (d?.online != null) setOnlineCount(d.online); })
         .catch(() => {});
     };
     fetchOnline();
-    const id = setInterval(fetchOnline, 60_000);
-    return () => clearInterval(id);
+    const handleVisibilityChange = () => {
+      if (document.visibilityState === "visible") fetchOnline();
+    };
+    document.addEventListener("visibilitychange", handleVisibilityChange);
+    const id = setInterval(fetchOnline, ONLINE_USERS_REFRESH_MS);
+    return () => {
+      document.removeEventListener("visibilitychange", handleVisibilityChange);
+      clearInterval(id);
+    };
   }, []);
 
   const [gridCols, setGridCols] = useState<number>(() => {

frontend/components/dashboard/scan-terminal/LiveTemperatureThresholdChart.tsx

@@ -101,6 +101,10 @@ function formatCityLocalDate(tzOffsetSeconds: number | null | undefined) {
   return `${y}-${m}-${d}`;
 }
 
+function getLiveTempFromHourly(data: HourlyForecast) {
+  return validNumber(data?.airportCurrent?.temp) ?? validNumber(data?.airportPrimary?.temp) ?? null;
+}
+
 function getWundergroundDailyHigh(hourly: HourlyForecast) {
   return validNumber(hourly?.wundergroundCurrent?.max_so_far) ?? null;
 }
@@ -365,6 +369,8 @@ export function LiveTemperatureThresholdChart({
         .then((data) => {
           if (cancelled || !data) return;
           hasLoadedHourlyDetailRef.current = true;
+          const temp = getLiveTempFromHourly(data);
+          if (temp !== null) setLiveTemp(temp);
           setHourly(data);
         })
         .catch(() => {})
@@ -377,15 +383,6 @@ export function LiveTemperatureThresholdChart({
       if (typeof document !== "undefined" && document.visibilityState === "hidden") return;
       if (Date.now() - lastPatchAtRef.current < 2 * 60_000) return;
 
-      fetch(`/api/city/${encodeURIComponent(city)}/summary`)
-        .then((res) => (res.ok ? res.json() : null))
-        .then((payload) => {
-          if (cancelled || !payload) return;
-          const temp = validNumber(payload?.current?.temp);
-          if (temp !== null) setLiveTemp(temp);
-        })
-        .catch(() => {});
-
       refreshFullDetail();
     };
 
@@ -403,19 +400,12 @@ export function LiveTemperatureThresholdChart({
     const refreshForegroundFullDetail = () => {
       lastPatchAtRef.current = Date.now();
 
-      fetch(`/api/city/${encodeURIComponent(city)}/summary`)
-        .then((res) => (res.ok ? res.json() : null))
-        .then((payload) => {
-          if (cancelled || !payload) return;
-          const temp = validNumber(payload?.current?.temp);
-          if (temp !== null) setLiveTemp(temp);
-        })
-        .catch(() => {});
-
       fetchHourlyForecastForCity(city, { ignoreCache: true, resolution: targetResolution })
         .then((data) => {
           if (cancelled || !data) return;
           hasLoadedHourlyDetailRef.current = true;
+          const temp = getLiveTempFromHourly(data);
+          if (temp !== null) setLiveTemp(temp);
           setHourly(data);
         })
         .catch(() => {});

frontend/components/dashboard/scan-terminal/__tests__/refreshCadencePolicy.test.ts

@@ -49,6 +49,10 @@ export async function runTests() {
     path.join(projectRoot, "components", "dashboard", "scan-terminal", "temperature-chart-logic.ts"),
     "utf8",
   );
+  const dashboardSource = fs.readFileSync(
+    path.join(projectRoot, "components", "dashboard", "ScanTerminalDashboard.tsx"),
+    "utf8",
+  );
 
   assert(
     querySource.includes("useSsePatchVersion") &&
@@ -91,10 +95,16 @@ export async function runTests() {
       chartLogicSource.includes("primeCityDetailCache"),
     "visible terminal chart detail fetches should be coalesced into one batch request and prime the shared chart cache",
   );
+  const fetchHourlyBlock = chartLogicSource.match(/async function fetchHourlyForecastForCity[\s\S]*?\n}\n\nfunction fetchCityDetailWithTimeout/)?.[0] || "";
   assert(
-    chartLogicSource.includes("options.ignoreCache\n      ? runQueuedHourlyDetailRequest") &&
-      chartLogicSource.includes(": queueCityDetailBatch(city, resParam)"),
-    "normal first-paint city detail requests should enter the batch queue before single-request concurrency limiting",
+    fetchHourlyBlock.includes("queueCityDetailBatch(city, resParam)") &&
+      !fetchHourlyBlock.includes("runQueuedHourlyDetailRequest"),
+    "first-paint and background city detail refreshes should both enter the batch queue before falling back to single requests",
+  );
+  assert(
+    dashboardSource.includes("ONLINE_USERS_REFRESH_MS = 5 * 60_000") &&
+      dashboardSource.includes('document.visibilityState === "hidden"'),
+    "terminal online-user presence should refresh slowly and pause while the browser tab is hidden",
   );
   assert(
     chartSource.includes("IntersectionObserver") &&

frontend/components/dashboard/scan-terminal/__tests__/ssePatchArchitecture.test.ts

@@ -182,6 +182,10 @@ export function runTests() {
       !foregroundRefreshBlock.includes("setIsHourlyLoading(true)"),
     "foreground resume refresh should update full detail immediately in the background without showing the loading overlay",
   );
+  assert(
+    !chart.includes("/api/city/${encodeURIComponent(city)}/summary"),
+    "visible chart fallback and foreground refresh should not issue a separate summary request after requesting full detail",
+  );
   assert(chart.includes("viewMode"), "temperature chart must expose a view mode for DEB-peak auto view versus full-day view");
   assert(chart.includes('useState<"auto" | "full">("full")'), "temperature chart must default every city panel to the all-day view");
   assert(

frontend/components/dashboard/scan-terminal/temperature-chart-logic.ts

@@ -1098,7 +1098,10 @@ async function flushCityDetailBatch(resolution: string) {
           return;
         }
         try {
-          resolveBatchWaiters(waiters, await fetchSingleHourlyForecastForCity(city, resolution));
+          resolveBatchWaiters(
+            waiters,
+            await runQueuedHourlyDetailRequest(() => fetchSingleHourlyForecastForCity(city, resolution)),
+          );
         } catch (error) {
           rejectBatchWaiters(waiters, error);
         }
@@ -1109,7 +1112,10 @@ async function flushCityDetailBatch(resolution: string) {
       cities.map(async (city) => {
         const waiters = queue.waiters.get(city);
         try {
-          resolveBatchWaiters(waiters, await fetchSingleHourlyForecastForCity(city, resolution));
+          resolveBatchWaiters(
+            waiters,
+            await runQueuedHourlyDetailRequest(() => fetchSingleHourlyForecastForCity(city, resolution)),
+          );
         } catch (fallbackError) {
           rejectBatchWaiters(waiters, fallbackError || error);
         }
@@ -1158,11 +1164,7 @@ async function fetchHourlyForecastForCity(
   const pending = _hourlyRequestCache.get(requestKey);
   if (pending) return pending;
 
-  const request = (
-    options.ignoreCache
-      ? runQueuedHourlyDetailRequest(() => fetchSingleHourlyForecastForCity(city, resParam))
-      : queueCityDetailBatch(city, resParam)
-  )
+  const request = queueCityDetailBatch(city, resParam)
     .finally(() => {
       _hourlyRequestCache.delete(requestKey);
     });