fix(presence) : count visitors per browser

hooks/use-presence.ts

@@ -14,22 +14,39 @@ export type EditorsByGuide = Record<
   Array<{ userId: string; name: string; sections: string[] }>
 >;
 
-function tabId(storageKey: string): string {
-  const existing = window.sessionStorage.getItem(storageKey);
-  if (existing) return existing;
-  const created = crypto.randomUUID();
-  window.sessionStorage.setItem(storageKey, created);
-  return created;
+const visitorIdStorageKey = "buzz-sheet:visitor-id";
+
+let currentTabId: string | undefined;
+let fallbackVisitorId: string | undefined;
+
+function tabId(): string {
+  currentTabId ??= crypto.randomUUID();
+  return currentTabId;
+}
+
+function visitorId(): string {
+  try {
+    const existing = window.localStorage.getItem(visitorIdStorageKey);
+    if (existing) return existing;
+    const created = crypto.randomUUID();
+    window.localStorage.setItem(visitorIdStorageKey, created);
+    return created;
+  } catch {
+    fallbackVisitorId ??= crypto.randomUUID();
+    return fallbackVisitorId;
+  }
 }
 
 function useHeartbeat<T>({
   endpoint,
   guideId,
   section,
+  identifyBy,
 }: {
   endpoint: string;
   guideId: string | null;
   section?: string | null;
+  identifyBy: "browser" | "tab";
 }) {
   const [value, setValue] = useState<T | null>(null);
   const send = useEffectEvent(async (active = true) => {
@@ -38,7 +55,7 @@ function useHeartbeat<T>({
         method: "POST",
         headers: { "Content-Type": "application/json" },
         body: JSON.stringify({
-          tabId: tabId(`buzz-sheet:${endpoint}:tab`),
+          tabId: identifyBy === "browser" ? visitorId() : tabId(),
           guideId,
           ...(section !== undefined ? { section } : {}),
           active,
@@ -59,7 +76,9 @@ function useHeartbeat<T>({
     const refresh = () => {
       if (document.visibilityState === "visible") void send();
     };
-    const leave = () => void send(false);
+    const leave = () => {
+      if (identifyBy === "tab") void send(false);
+    };
     window.addEventListener("focus", refresh);
     window.addEventListener("pagehide", leave);
     document.addEventListener("visibilitychange", refresh);
@@ -70,13 +89,17 @@ function useHeartbeat<T>({
       window.removeEventListener("pagehide", leave);
       document.removeEventListener("visibilitychange", refresh);
     };
-  }, [endpoint, guideId, section]);
+  }, [endpoint, guideId, identifyBy, section]);
 
   return value;
 }
 
 export function useVisitorPresence(guideId: string | null) {
-  return useHeartbeat<VisitorCounts>({ endpoint: "/api/presence/visitors", guideId });
+  return useHeartbeat<VisitorCounts>({
+    endpoint: "/api/presence/visitors",
+    guideId,
+    identifyBy: "browser",
+  });
 }
 
 export function useAdminPresence(guideId: string | null, section: string | null = null) {
@@ -84,5 +107,6 @@ export function useAdminPresence(guideId: string | null, section: string | null
     endpoint: "/api/presence/admin",
     guideId,
     section,
+    identifyBy: "tab",
   });
 }