support for resume on multiple devices, fix camera freeze bug when opening setup overlay

frontend/app.js

@@ -824,6 +824,11 @@ function showSetupOverlay() {
 
 function hideSetupOverlay() {
     document.getElementById('setup-overlay').classList.remove('active');
+
+    // Resume animation if a trip is active
+    if (localStorage.getItem(LOCATION_STORAGE)) {
+        startCameraAnimation();
+    }
 }
 
 function setupEventListeners() {
@@ -989,6 +994,8 @@ async function calculateAndStartRoute(startAddress, endAddress, isRestoring = fa
             // Reset display steps for visual consistency
             displayTripSteps = 0;
             stateBuffer = [];
+            window.lastPositionUpdateDistance = 0;
+            window.lastPanoUpdate = 0;
 
             startFromLocation(leg.start_location, locationData.startAddress);
             hideSetupOverlay();
@@ -1169,7 +1176,7 @@ function resetLocation() {
     showSetupOverlay();
     document.getElementById('startLocationInput').value = '';
     document.getElementById('endLocationInput').value = '';
-    stopAnimation();
+    // stopAnimation(); // Don't stop animation just because we opened the setup overlay
 }
 
 // Rate limiting for refresh
@@ -1230,14 +1237,64 @@ async function fetchStatus() {
         const data = await response.json();
         const now = Date.now();
 
-        // Update target steps from server
-        if (data.tripSteps !== undefined) {
-            // Add to buffer
-            stateBuffer.push({ t: now, s: data.tripSteps });
+        // Server-Side Trip Synchronization
+        if (data.activeTrip) {
+            // A trip is active on the server
 
-            // Keep buffer size manageable (20 points is ~1.5 mins)
-            if (stateBuffer.length > 20) {
-                stateBuffer.shift();
+            // Check if we need to sync/resume this trip locally
+            const localLocation = localStorage.getItem(LOCATION_STORAGE);
+            let needsResync = false;
+
+            if (!localLocation) {
+                needsResync = true;
+                console.log("[Sync] No local trip found. Syncing from server.");
+            } else {
+                // We have a local trip, check if it's the SAME trip
+                try {
+                    const localData = JSON.parse(localLocation);
+                    if (localData.routeName !== data.activeTrip.route_name) {
+                        needsResync = true;
+                        console.log("[Sync] Local trip route mismatch. Syncing from server.");
+                    }
+                } catch (e) {
+                    needsResync = true;
+                }
+            }
+
+            if (needsResync) {
+                syncActiveTrip(data.activeTrip);
+            }
+
+            // Update target steps from server
+            if (data.tripSteps !== undefined) {
+                // Safety: Only accept step updates if they are for the current trip
+                if (needsResync) {
+                    stateBuffer = [];
+                    displayTripSteps = 0;
+                }
+
+                stateBuffer.push({ t: now, s: data.tripSteps });
+
+                // Keep buffer size manageable (20 points is ~1.5 mins)
+                if (stateBuffer.length > 20) {
+                    stateBuffer.shift();
+                }
+            }
+        } else {
+            // No trip active on the server
+            if (localStorage.getItem(LOCATION_STORAGE)) {
+                console.log("[Sync] No trip on server. Clearing local trip.");
+                localStorage.removeItem(LOCATION_STORAGE);
+
+                if (!document.getElementById('celebration-overlay').classList.contains('active')) {
+                    document.getElementById('routeInfo').textContent = 'Not Started';
+                    document.getElementById('currentSteps').textContent = '0';
+                    document.getElementById('tripMeter').textContent = '0.0 / 0.0 km';
+                    masterPath = [];
+                    routeTotalDistance = 0;
+                    displayTripSteps = 0;
+                    stateBuffer = [];
+                }
             }
         }
 
@@ -1254,6 +1311,24 @@ async function fetchStatus() {
     }
 }
 
+async function syncActiveTrip(activeTrip) {
+    console.log("[Sync] Restoring trip from server:", activeTrip.route_name);
+
+    if (activeTrip.trip_type === 'address') {
+        calculateAndStartRoute(activeTrip.start_address, activeTrip.end_address, true);
+    } else if (activeTrip.trip_type === 'kml') {
+        try {
+            const response = await fetch(`/api/kml/download?owner_id=${activeTrip.kml_owner_id || currentUserID}&filename=${encodeURIComponent(activeTrip.route_name)}`);
+            if (response.ok) {
+                const kmlContent = await response.text();
+                processKML(kmlContent, activeTrip.route_name);
+            }
+        } catch (err) {
+            console.error("[Sync] Failed to download KML for sync:", err);
+        }
+    }
+}
+
 function updateNextSyncCountdown(nextSyncTime) {
     const now = new Date();
     const diff = nextSyncTime - now;
@@ -2154,6 +2229,8 @@ function startFromCustomRoute(pathData, routeName, isRestoring = false, markers
     // Reset display steps
     displayTripSteps = 0;
     stateBuffer = [];
+    window.lastPositionUpdateDistance = 0;
+    window.lastPanoUpdate = 0;
 
     // Initialize Map View
     startFromLocation(startPoint, routeName);
@@ -2301,6 +2378,14 @@ async function triggerCelebration(finalDistance) {
     currentTripDetails = null;
     masterPath = [];
     routeTotalDistance = 0;
+    displayTripSteps = 0;
+    stateBuffer = [];
+
+    // Update UI to reflect reset
+    document.getElementById('routeInfo').textContent = 'Not Started';
+    document.getElementById('currentSteps').textContent = '0';
+    document.getElementById('tripMeter').textContent = '0.0 / 0.0 km';
+
     // We keep window.hasCelebrated = true to prevent immediate re-trigger 
     // but starting a new trip will reset it.
 }

server/step_manager.go

@@ -360,10 +360,26 @@ func (sm *StepManager) GetStatus() map[string]interface{} {
 		go sm.Sync() // Async sync
 	}
 
-	return map[string]interface{}{
+	res := map[string]interface{}{
 		"tripSteps":    currentSmoothed,
 		"nextSyncTime": nextSyncMilli,
 	}
+
+	sm.mu.Lock()
+	if sm.tripState.StartDate != "" {
+		res["activeTrip"] = map[string]interface{}{
+			"trip_type":      sm.tripState.TripType,
+			"route_name":     sm.tripState.RouteName,
+			"start_address":  sm.tripState.StartAddress,
+			"end_address":    sm.tripState.EndAddress,
+			"kml_id":         sm.tripState.KmlID,
+			"total_distance": sm.tripState.TotalDistance,
+			"start_time":     sm.tripState.StartTime,
+		}
+	}
+	sm.mu.Unlock()
+
+	return res
 }
 
 // RecalculateTotalFromState sums up the steps from the DailyCache without making external API calls