url and history

web/src/App.tsx

@@ -48,6 +48,32 @@ type ContextMenuState = {
   y: number;
 };
 
+function readSidebarSelectionFromUrl(): SidebarSelection | null {
+  if (typeof window === "undefined") return null;
+  const params = new URLSearchParams(window.location.search);
+  const chatId = params.get("chat")?.trim();
+  if (chatId) {
+    return { kind: "chat", id: chatId };
+  }
+  const searchId = params.get("search")?.trim();
+  if (searchId) {
+    return { kind: "search", id: searchId };
+  }
+  return null;
+}
+
+function buildWorkspaceUrl(selection: SidebarSelection | null) {
+  if (typeof window === "undefined") return "/";
+  const params = new URLSearchParams(window.location.search);
+  params.delete("chat");
+  params.delete("search");
+  if (selection) {
+    params.set(selection.kind === "chat" ? "chat" : "search", selection.id);
+  }
+  const query = params.toString();
+  return `${window.location.pathname}${query ? `?${query}` : ""}`;
+}
+
 const PROVIDER_FALLBACK_MODELS: Record<Provider, string[]> = {
   openai: ["gpt-4.1-mini"],
   anthropic: ["claude-3-5-sonnet-latest"],
@@ -302,6 +328,8 @@ export default function App() {
   const searchRunCounterRef = useRef(0);
   const [contextMenu, setContextMenu] = useState<ContextMenuState | null>(null);
   const [isMobileSidebarOpen, setIsMobileSidebarOpen] = useState(false);
+  const initialRouteSelectionRef = useRef<SidebarSelection | null>(readSidebarSelectionFromUrl());
+  const hasSyncedSelectionHistoryRef = useRef(false);
 
   useEffect(() => {
     if (typeof document === "undefined") return;
@@ -417,9 +445,43 @@ export default function App() {
 
   useEffect(() => {
     if (!isAuthenticated) return;
-    void Promise.all([refreshCollections(), refreshModels()]);
+    const preferredSelection = initialRouteSelectionRef.current;
+    initialRouteSelectionRef.current = null;
+    void Promise.all([refreshCollections(preferredSelection ?? undefined), refreshModels()]);
   }, [isAuthenticated]);
 
+  useEffect(() => {
+    const onPopState = () => {
+      setContextMenu(null);
+      setDraftKind(null);
+      setSelectedItem(readSidebarSelectionFromUrl());
+      setIsMobileSidebarOpen(false);
+    };
+    window.addEventListener("popstate", onPopState);
+    return () => window.removeEventListener("popstate", onPopState);
+  }, []);
+
+  useEffect(() => {
+    if (!isAuthenticated) {
+      hasSyncedSelectionHistoryRef.current = false;
+      return;
+    }
+    const current = `${window.location.pathname}${window.location.search}`;
+    const next = buildWorkspaceUrl(selectedItem);
+
+    if (!hasSyncedSelectionHistoryRef.current) {
+      hasSyncedSelectionHistoryRef.current = true;
+      if (current !== next) {
+        window.history.replaceState({}, "", next);
+      }
+      return;
+    }
+
+    if (current !== next) {
+      window.history.pushState({}, "", next);
+    }
+  }, [isAuthenticated, selectedItem]);
+
   const providerModelOptions = useMemo(() => getModelOptions(modelCatalog, provider), [modelCatalog, provider]);
 
   useEffect(() => {