M5: Energy view — per-metric decimal formatting and chart auto-refresh toggle

frontend/src/energy/hooks.ts

@@ -132,11 +132,28 @@ export function useTestReadDevice() {
   })
 }
 
+// ---------------------------------------------------------------------------
+// Query options shared by auto-refresh–capable queries
+// ---------------------------------------------------------------------------
+
+export interface AutoRefreshOptions {
+  /**
+   * When provided, TanStack Query will automatically re-fetch this query at
+   * this interval (milliseconds).  Pass `undefined` to disable auto-refresh.
+   * Minimum enforced value: 2 000 ms.
+   */
+  refetchIntervalMs?: number
+}
+
 // ---------------------------------------------------------------------------
 // Query: latest reading for a device
 // ---------------------------------------------------------------------------
 
-export function useLatestReading(uuid: string) {
+export function useLatestReading(uuid: string, options?: AutoRefreshOptions) {
+  const refetchInterval = options?.refetchIntervalMs != null
+    ? Math.max(2_000, options.refetchIntervalMs)
+    : undefined
+
   return useQuery({
     queryKey: ['modbus-latest', uuid],
     queryFn: async () => {
@@ -145,8 +162,7 @@ export function useLatestReading(uuid: string) {
       })
       return res.data
     },
-    // Refresh every 10 s to show up-to-date readings.
-    refetchInterval: 10_000,
+    refetchInterval,
   })
 }
 
@@ -175,10 +191,18 @@ export function useMetrics(uuid: string) {
 /** Hard upper-bound on readings fetched; prevents accidental full-table pulls. */
 const READINGS_MAX_LIMIT = 1000
 
-export function useReadings(uuid: string, params: ReadingsQueryParams) {
+export function useReadings(
+  uuid: string,
+  params: ReadingsQueryParams,
+  options?: AutoRefreshOptions,
+) {
   const { start, end, limit } = params
   const effectiveLimit = Math.min(limit ?? READINGS_MAX_LIMIT, READINGS_MAX_LIMIT)
 
+  const refetchInterval = options?.refetchIntervalMs != null
+    ? Math.max(2_000, options.refetchIntervalMs)
+    : undefined
+
   return useQuery({
     queryKey: ['modbus-readings', uuid, { start, end, limit: effectiveLimit }],
     queryFn: async () => {
@@ -196,5 +220,6 @@ export function useReadings(uuid: string, params: ReadingsQueryParams) {
     },
     // Enabled only when we have valid uuid; start/end may be null (full window).
     enabled: !!uuid,
+    refetchInterval,
   })
 }