Add live Prometheus telemetry endpoint

script.js

@@ -1,4 +1,17 @@
 const timeElement = document.querySelector("#local-time");
+const refreshElement = document.querySelector("#refresh-indicator");
+
+const fields = {
+  cpu: document.querySelector("#cpu-value"),
+  memory: document.querySelector("#memory-value"),
+  uptime: document.querySelector("#uptime-value"),
+  containers: document.querySelector("#containers-value"),
+  targets: document.querySelector("#targets-value"),
+  telemetry: document.querySelector("#telemetry-value"),
+};
+
+let lastSuccessfulUpdate = null;
+let requestInFlight = false;
 
 function updateClock() {
   const now = new Date();
@@ -11,5 +24,73 @@ function updateClock() {
   }).format(now);
 }
 
+function formatUptime(totalSeconds) {
+  const seconds = Math.max(0, Number(totalSeconds) || 0);
+  const days = Math.floor(seconds / 86400);
+  const hours = Math.floor((seconds % 86400) / 3600);
+  const minutes = Math.floor((seconds % 3600) / 60);
+
+  if (days > 0) return days + "d " + hours + "h";
+  if (hours > 0) return hours + "h " + minutes + "m";
+  return minutes + "m";
+}
+
+function setUnavailable() {
+  for (const key of ["cpu", "memory", "uptime", "containers", "targets"]) {
+    fields[key].textContent = "--";
+  }
+  fields.telemetry.textContent = "UNAVAILABLE";
+  fields.telemetry.classList.add("metric-error");
+  refreshElement.textContent = "TELEMETRY UNAVAILABLE";
+  refreshElement.classList.add("telemetry-error");
+}
+
+function renderStatus(data) {
+  fields.cpu.textContent = Number(data.host.cpu_percent).toFixed(1);
+  fields.memory.textContent = Number(data.host.memory_percent).toFixed(1);
+  fields.uptime.textContent = formatUptime(data.host.uptime_seconds);
+  fields.containers.textContent = String(data.containers.running);
+  fields.targets.textContent = data.prometheus.up + "/" + data.prometheus.total;
+  fields.telemetry.textContent = "LIVE";
+  fields.telemetry.classList.remove("metric-error");
+  refreshElement.classList.remove("telemetry-error");
+
+  lastSuccessfulUpdate = Date.now();
+  updateRefreshLabel();
+}
+
+function updateRefreshLabel() {
+  if (!lastSuccessfulUpdate) return;
+  const ageSeconds = Math.max(0, Math.floor((Date.now() - lastSuccessfulUpdate) / 1000));
+  refreshElement.textContent = "LIVE TELEMETRY · UPDATED " + String(ageSeconds).padStart(2, "0") + "s AGO";
+}
+
+async function refreshTelemetry() {
+  if (requestInFlight) return;
+  requestInFlight = true;
+
+  try {
+    const response = await fetch("/api/status", {
+      cache: "no-store",
+      headers: { "Accept": "application/json" },
+    });
+
+    if (!response.ok) throw new Error("status " + response.status);
+    const data = await response.json();
+    if (!data.ok) throw new Error("telemetry unavailable");
+
+    renderStatus(data);
+  } catch (error) {
+    console.error("ByteGeist telemetry request failed:", error);
+    setUnavailable();
+  } finally {
+    requestInFlight = false;
+  }
+}
+
 updateClock();
+refreshTelemetry();
+
 window.setInterval(updateClock, 1000);
+window.setInterval(updateRefreshLabel, 1000);
+window.setInterval(refreshTelemetry, 15000);