1 files changed, 61 insertions, 0 deletions
diff --git a/web/src/counts.js b/web/src/counts.js
new file mode 100644
index 0000000..1b98bbe
--- /dev/null
+++ b/web/src/counts.js
@@ -0,0 +1,61 @@
+import { api } from './api.js';
+import { getOnlineCount } from './multiplayer.js';
+import { getUser, onAuthChange } from './auth.js';
+
+// Live counts for the badges on the Friends and Multiplayer controls: how
+// many people you can race right now, and how many friends you have.
+//
+// Shared and cached rather than fetched per control. The rail is rebuilt on
+// every screen change, and without this each navigation fired a fresh pair of
+// requests - and the main menu's Multiplayer button would have fired its own
+// on top of that, asking the server the same question twice per screen.
+const REFRESH_MS = 30000;
+
+let cache = { online: 0, friends: 0 };
+const listeners = new Set();
+let timer = null;
+let inFlight = false;
+
+async function refresh() {
+    if (inFlight) return;
+    inFlight = true;
+    try {
+        const online = await getOnlineCount().then(r => r.players).catch(() => cache.online);
+        // Friends only exist for a signed-in user; asking while signed out is
+        // a guaranteed 401, so skip it rather than log noise on every poll.
+        const friends = getUser()
+            ? await api.get('/api/friends').then(r => (r.friends || []).length).catch(() => cache.friends)
+            : 0;
+        cache = { online, friends };
+        for (const fn of listeners) fn(cache);
+    } finally {
+        inFlight = false;
+    }
+}
+
+export function getCounts() {
+    return cache;
+}
+
+// Returns an unsubscribe function. Polling runs only while something is
+// listening, so a screen with no badges costs nothing.
+export function onCountsChange(fn) {
+    listeners.add(fn);
+    if (!timer) {
+        refresh();
+        timer = setInterval(refresh, REFRESH_MS);
+    }
+    return () => {
+        listeners.delete(fn);
+        if (listeners.size === 0 && timer) {
+            clearInterval(timer);
+            timer = null;
+        }
+    };
+}
+
+// Signing in or out changes the friend count immediately - waiting up to the
+// full poll interval would leave a stale badge behind.
+onAuthChange(() => {
+    if (listeners.size > 0) refresh();
+});