CATALYST-1532: fix(core) - Fix analytics visit count inflation (#2916)

Resolve inflated visitor counts caused by three issues:

- Visit cookie used a fixed TTL instead of a sliding window, creating
  new visits for users browsing longer than 30 minutes. Now refreshes
  the cookie TTL on every request.
- Prefetch and RSC requests triggered new visit and product view events.
  Now guards against Next-Router-Prefetch and RSC headers so only real
  navigations fire analytics mutations.
- Locale redirects from withIntl bypassed analytics entirely. Reorder
  middleware so withAnalyticsCookies runs before withIntl, ensuring
  cookies survive redirect responses.

Fixes CATALYST-1532

Co-authored-by: Claude <noreply@anthropic.com>

Author: chanceaclark

.changeset/fix-analytics-visit-inflation.md

@@ -0,0 +1,5 @@
+---
+"@bigcommerce/catalyst-core": patch
+---
+
+Fix analytics visit count inflation by implementing a sliding window for the visit cookie TTL, guarding against prefetch/RSC requests creating spurious visits, and reordering middleware so analytics cookies survive locale redirects.

core/middleware.ts

@@ -7,8 +7,8 @@ import { withRoutes } from './middlewares/with-routes';
 
 export const middleware = composeMiddlewares(
   withAuth,
-  withIntl,
   withAnalyticsCookies,
+  withIntl,
   withChannelId,
   withRoutes,
 );

core/middlewares/with-analytics-cookies.ts

@@ -12,22 +12,30 @@ import { MiddlewareFactory } from './compose-middlewares';
 
 export const withAnalyticsCookies: MiddlewareFactory = (next) => {
   return async (request, event) => {
-    let visitorId = await getVisitorIdCookie();
-    let visitId = await getVisitIdCookie();
+    const existingVisitorId = await getVisitorIdCookie();
+    const existingVisitId = await getVisitIdCookie();
 
-    if (!visitorId || !isUuid(visitorId)) {
-      visitorId = uuidv4();
-    }
+    const isPrefetch = request.headers.get('Next-Router-Prefetch') === '1';
+    const isRSC = request.headers.get('RSC') === '1';
+
+    const visitorId = existingVisitorId && isUuid(existingVisitorId) ? existingVisitorId : uuidv4();
 
-    // Update the visitorId cookie every time
     await setVisitorIdCookie(visitorId);
 
-    if (!visitId || !isUuid(visitId)) {
-      visitId = uuidv4();
-      await setVisitIdCookie(visitId);
+    const hasValidVisit = existingVisitId != null && isUuid(existingVisitId);
 
+    if (hasValidVisit) {
+      // Sliding window: refresh the TTL on every request
+      await setVisitIdCookie(existingVisitId);
+    } else if (!isPrefetch && !isRSC) {
+      // New visit on a real navigation: create cookie and fire event
+      const visitId = uuidv4();
+
+      await setVisitIdCookie(visitId);
       event.waitUntil(recordNewVisit(request, visitorId, visitId));
     }
+    // Prefetch/RSC with no valid visit: skip entirely so the
+    // subsequent real navigation properly detects a new visit.
 
     return next(request, event);
   };

core/middlewares/with-routes.ts

@@ -369,7 +369,12 @@ export const withRoutes: MiddlewareFactory = () => {
       case 'Product': {
         url = `/${locale}/product/${node.entityId}`;
 
-        event.waitUntil(recordProductVisit(request, node.entityId));
+        const isPrefetch = request.headers.get('Next-Router-Prefetch') === '1';
+        const isRSC = request.headers.get('RSC') === '1';
+
+        if (!isPrefetch && !isRSC) {
+          event.waitUntil(recordProductVisit(request, node.entityId));
+        }
 
         break;
       }