Preserve repeater values when browsing away

frontend/src/components/repeater/repeaterPaneShared.tsx

@@ -80,6 +80,28 @@ export function formatAdvertInterval(val: string | null): string {
   return `${trimmed}h`;
 }
 
+function formatFetchedRelative(fetchedAt: number): string {
+  const elapsedSeconds = Math.max(0, Math.floor((Date.now() - fetchedAt) / 1000));
+
+  if (elapsedSeconds < 60) return 'Just now';
+
+  const elapsedMinutes = Math.floor(elapsedSeconds / 60);
+  if (elapsedMinutes < 60) {
+    return `${elapsedMinutes} minute${elapsedMinutes === 1 ? '' : 's'} ago`;
+  }
+
+  const elapsedHours = Math.floor(elapsedMinutes / 60);
+  return `${elapsedHours} hour${elapsedHours === 1 ? '' : 's'} ago`;
+}
+
+function formatFetchedTime(fetchedAt: number): string {
+  return new Date(fetchedAt).toLocaleTimeString([], {
+    hour: 'numeric',
+    minute: '2-digit',
+    second: '2-digit',
+  });
+}
+
 // --- Generic Pane Wrapper ---
 
 export function RepeaterPane({
@@ -99,10 +121,22 @@ export function RepeaterPane({
   className?: string;
   contentClassName?: string;
 }) {
+  const fetchedAt = state.fetched_at ?? null;
+
   return (
     <div className={cn('border border-border rounded-lg overflow-hidden', className)}>
       <div className="flex items-center justify-between px-3 py-2 bg-muted/50 border-b border-border">
-        <h3 className="text-sm font-medium">{title}</h3>
+        <div className="min-w-0">
+          <h3 className="text-sm font-medium">{title}</h3>
+          {fetchedAt && (
+            <p
+              className="text-[11px] text-muted-foreground"
+              title={new Date(fetchedAt).toLocaleString()}
+            >
+              Fetched {formatFetchedTime(fetchedAt)} ({formatFetchedRelative(fetchedAt)})
+            </p>
+          )}
+        </div>
         {onRefresh && (
           <button
             type="button"

frontend/src/hooks/useRepeaterDashboard.ts

@@ -17,6 +17,7 @@ import type {
 
 const MAX_RETRIES = 3;
 const RETRY_DELAY_MS = 2000;
+const MAX_CACHED_REPEATERS = 20;
 
 interface ConsoleEntry {
   command: string;
@@ -35,7 +36,15 @@ interface PaneData {
   lppTelemetry: RepeaterLppTelemetryResponse | null;
 }
 
-const INITIAL_PANE_STATE: PaneState = { loading: false, attempt: 0, error: null };
+interface RepeaterDashboardCacheEntry {
+  loggedIn: boolean;
+  loginError: string | null;
+  paneData: PaneData;
+  paneStates: Record<PaneName, PaneState>;
+  consoleHistory: ConsoleEntry[];
+}
+
+const INITIAL_PANE_STATE: PaneState = { loading: false, attempt: 0, error: null, fetched_at: null };
 
 function createInitialPaneStates(): Record<PaneName, PaneState> {
   return {
@@ -61,6 +70,67 @@ function createInitialPaneData(): PaneData {
   };
 }
 
+const repeaterDashboardCache = new Map<string, RepeaterDashboardCacheEntry>();
+
+function clonePaneData(data: PaneData): PaneData {
+  return { ...data };
+}
+
+function normalizePaneStates(paneStates: Record<PaneName, PaneState>): Record<PaneName, PaneState> {
+  return {
+    status: { ...paneStates.status, loading: false },
+    neighbors: { ...paneStates.neighbors, loading: false },
+    acl: { ...paneStates.acl, loading: false },
+    radioSettings: { ...paneStates.radioSettings, loading: false },
+    advertIntervals: { ...paneStates.advertIntervals, loading: false },
+    ownerInfo: { ...paneStates.ownerInfo, loading: false },
+    lppTelemetry: { ...paneStates.lppTelemetry, loading: false },
+  };
+}
+
+function cloneConsoleHistory(consoleHistory: ConsoleEntry[]): ConsoleEntry[] {
+  return consoleHistory.map((entry) => ({ ...entry }));
+}
+
+function getCachedState(publicKey: string | null): RepeaterDashboardCacheEntry | null {
+  if (!publicKey) return null;
+  const cached = repeaterDashboardCache.get(publicKey);
+  if (!cached) return null;
+
+  repeaterDashboardCache.delete(publicKey);
+  repeaterDashboardCache.set(publicKey, cached);
+
+  return {
+    loggedIn: cached.loggedIn,
+    loginError: cached.loginError,
+    paneData: clonePaneData(cached.paneData),
+    paneStates: normalizePaneStates(cached.paneStates),
+    consoleHistory: cloneConsoleHistory(cached.consoleHistory),
+  };
+}
+
+function cacheState(publicKey: string, entry: RepeaterDashboardCacheEntry) {
+  repeaterDashboardCache.delete(publicKey);
+  repeaterDashboardCache.set(publicKey, {
+    loggedIn: entry.loggedIn,
+    loginError: entry.loginError,
+    paneData: clonePaneData(entry.paneData),
+    paneStates: normalizePaneStates(entry.paneStates),
+    consoleHistory: cloneConsoleHistory(entry.consoleHistory),
+  });
+
+  if (repeaterDashboardCache.size > MAX_CACHED_REPEATERS) {
+    const lruKey = repeaterDashboardCache.keys().next().value as string | undefined;
+    if (lruKey) {
+      repeaterDashboardCache.delete(lruKey);
+    }
+  }
+}
+
+export function resetRepeaterDashboardCacheForTests() {
+  repeaterDashboardCache.clear();
+}
+
 // Maps pane name to the API call
 function fetchPaneData(publicKey: string, pane: PaneName) {
   switch (pane) {
@@ -102,15 +172,24 @@ export interface UseRepeaterDashboardResult {
 export function useRepeaterDashboard(
   activeConversation: Conversation | null
 ): UseRepeaterDashboardResult {
-  const [loggedIn, setLoggedIn] = useState(false);
+  const conversationId =
+    activeConversation && activeConversation.type === 'contact' ? activeConversation.id : null;
+  const cachedState = getCachedState(conversationId);
+
+  const [loggedIn, setLoggedIn] = useState(cachedState?.loggedIn ?? false);
   const [loginLoading, setLoginLoading] = useState(false);
-  const [loginError, setLoginError] = useState<string | null>(null);
+  const [loginError, setLoginError] = useState<string | null>(cachedState?.loginError ?? null);
 
-  const [paneData, setPaneData] = useState<PaneData>(createInitialPaneData);
-  const [paneStates, setPaneStates] =
-    useState<Record<PaneName, PaneState>>(createInitialPaneStates);
+  const [paneData, setPaneData] = useState<PaneData>(
+    cachedState?.paneData ?? createInitialPaneData
+  );
+  const [paneStates, setPaneStates] = useState<Record<PaneName, PaneState>>(
+    cachedState?.paneStates ?? createInitialPaneStates
+  );
 
-  const [consoleHistory, setConsoleHistory] = useState<ConsoleEntry[]>([]);
+  const [consoleHistory, setConsoleHistory] = useState<ConsoleEntry[]>(
+    cachedState?.consoleHistory ?? []
+  );
   const [consoleLoading, setConsoleLoading] = useState(false);
 
   // Track which conversation we're operating on to avoid stale updates after
@@ -120,6 +199,10 @@ export function useRepeaterDashboard(
 
   // Guard against setting state after unmount (retry timers firing late)
   const mountedRef = useRef(true);
+  useEffect(() => {
+    activeIdRef.current = conversationId;
+  }, [conversationId]);
+
   useEffect(() => {
     mountedRef.current = true;
     return () => {
@@ -127,6 +210,17 @@ export function useRepeaterDashboard(
     };
   }, []);
 
+  useEffect(() => {
+    if (!conversationId) return;
+    cacheState(conversationId, {
+      loggedIn,
+      loginError,
+      paneData,
+      paneStates,
+      consoleHistory,
+    });
+  }, [consoleHistory, conversationId, loggedIn, loginError, paneData, paneStates]);
+
   const getPublicKey = useCallback((): string | null => {
     if (!activeConversation || activeConversation.type !== 'contact') return null;
     return activeConversation.id;
@@ -172,7 +266,12 @@ export function useRepeaterDashboard(
 
         setPaneStates((prev) => ({
           ...prev,
-          [pane]: { loading: true, attempt, error: null },
+          [pane]: {
+            loading: true,
+            attempt,
+            error: null,
+            fetched_at: prev[pane].fetched_at ?? null,
+          },
         }));
 
         try {
@@ -182,7 +281,7 @@ export function useRepeaterDashboard(
           setPaneData((prev) => ({ ...prev, [pane]: data }));
           setPaneStates((prev) => ({
             ...prev,
-            [pane]: { loading: false, attempt, error: null },
+            [pane]: { loading: false, attempt, error: null, fetched_at: Date.now() },
           }));
           return; // Success
         } catch (err) {
@@ -193,7 +292,12 @@ export function useRepeaterDashboard(
           if (attempt === MAX_RETRIES) {
             setPaneStates((prev) => ({
               ...prev,
-              [pane]: { loading: false, attempt, error: msg },
+              [pane]: {
+                loading: false,
+                attempt,
+                error: msg,
+                fetched_at: prev[pane].fetched_at ?? null,
+              },
             }));
             toast.error(`Failed to fetch ${pane}`, { description: msg });
           } else {

frontend/src/test/repeaterDashboard.test.tsx

@@ -244,6 +244,20 @@ describe('RepeaterDashboard', () => {
     expect(screen.getByText('7.5 dB')).toBeInTheDocument();
   });
 
+  it('shows fetched time and relative age when pane data has been loaded', () => {
+    mockHook.loggedIn = true;
+    mockHook.paneStates.status = {
+      loading: false,
+      attempt: 1,
+      error: null,
+      fetched_at: Date.now(),
+    };
+
+    render(<RepeaterDashboard {...defaultProps} />);
+
+    expect(screen.getByText(/Fetched .*Just now/)).toBeInTheDocument();
+  });
+
   it('renders action buttons', () => {
     mockHook.loggedIn = true;
 

frontend/src/test/useRepeaterDashboard.test.ts

@@ -1,7 +1,10 @@
 import { StrictMode, createElement, type ReactNode } from 'react';
 import { describe, it, expect, vi, beforeEach, type Mock } from 'vitest';
 import { renderHook, act } from '@testing-library/react';
-import { useRepeaterDashboard } from '../hooks/useRepeaterDashboard';
+import {
+  resetRepeaterDashboardCacheForTests,
+  useRepeaterDashboard,
+} from '../hooks/useRepeaterDashboard';
 import type { Conversation } from '../types';
 
 // Mock the api module
@@ -43,6 +46,7 @@ const repeaterConversation: Conversation = {
 describe('useRepeaterDashboard', () => {
   beforeEach(() => {
     vi.clearAllMocks();
+    resetRepeaterDashboardCacheForTests();
   });
 
   it('starts with logged out state', () => {
@@ -123,6 +127,7 @@ describe('useRepeaterDashboard', () => {
     expect(result.current.paneData.status).toEqual(statusData);
     expect(result.current.paneStates.status.loading).toBe(false);
     expect(result.current.paneStates.status.error).toBe(null);
+    expect(result.current.paneStates.status.fetched_at).toEqual(expect.any(Number));
   });
 
   it('refreshPane still issues requests under StrictMode remount probing', async () => {
@@ -304,4 +309,38 @@ describe('useRepeaterDashboard', () => {
     expect(mockApi.repeaterOwnerInfo).toHaveBeenCalledTimes(1);
     expect(mockApi.repeaterLppTelemetry).toHaveBeenCalledTimes(1);
   });
+
+  it('restores dashboard state when navigating away and back to the same repeater', async () => {
+    const statusData = { battery_volts: 4.2 };
+    mockApi.repeaterLogin.mockResolvedValueOnce({ status: 'ok' });
+    mockApi.repeaterStatus.mockResolvedValueOnce(statusData);
+    mockApi.sendRepeaterCommand.mockResolvedValueOnce({
+      command: 'ver',
+      response: 'v2.1.0',
+      sender_timestamp: 1000,
+    });
+
+    const firstMount = renderHook(() => useRepeaterDashboard(repeaterConversation));
+
+    await act(async () => {
+      await firstMount.result.current.login('secret');
+      await firstMount.result.current.refreshPane('status');
+      await firstMount.result.current.sendConsoleCommand('ver');
+    });
+
+    expect(firstMount.result.current.loggedIn).toBe(true);
+    expect(firstMount.result.current.paneData.status).toEqual(statusData);
+    expect(firstMount.result.current.consoleHistory).toHaveLength(2);
+
+    firstMount.unmount();
+
+    const secondMount = renderHook(() => useRepeaterDashboard(repeaterConversation));
+
+    expect(secondMount.result.current.loggedIn).toBe(true);
+    expect(secondMount.result.current.loginError).toBe(null);
+    expect(secondMount.result.current.paneData.status).toEqual(statusData);
+    expect(secondMount.result.current.paneStates.status.loading).toBe(false);
+    expect(secondMount.result.current.consoleHistory).toHaveLength(2);
+    expect(secondMount.result.current.consoleHistory[1].response).toBe('v2.1.0');
+  });
 });

frontend/src/types.ts

@@ -364,6 +364,7 @@ export interface PaneState {
   loading: boolean;
   attempt: number;
   error: string | null;
+  fetched_at?: number | null;
 }
 
 export interface TraceResponse {