Preserve dashboard page across refreshes

web/src/App.tsx

@@ -47,6 +47,14 @@ const ShellTerminal = lazy(async () => {
 });
 
 type Screen = "loading" | "setup" | "login" | "dashboard" | "fatal";
+type DashboardPage = "home" | "car" | "adb" | "network" | "settings";
+
+const dashboardPages = new Set<DashboardPage>(["home", "car", "adb", "network", "settings"]);
+
+function pageFromLocation(): DashboardPage {
+  const page = window.location.hash.replace(/^#\/?/, "");
+  return dashboardPages.has(page as DashboardPage) ? (page as DashboardPage) : "home";
+}
 
 export function App() {
   const [screen, setScreen] = useState<Screen>("loading");
@@ -171,7 +179,7 @@ function AccountScreen({
 }
 
 function Dashboard({ auth, onLoggedOut }: { auth: AuthState; onLoggedOut: () => Promise<void> }) {
-  const [page, setPage] = useState<"home" | "car" | "adb" | "network" | "settings">("home");
+  const [page, setPage] = useState<DashboardPage>(pageFromLocation);
   const [status, setStatus] = useState<SystemStatus | null>(null);
   const [error, setError] = useState("");
   const [connection, setConnection] = useState<"connecting" | "live" | "offline">("connecting");
@@ -202,6 +210,17 @@ function Dashboard({ auth, onLoggedOut }: { auth: AuthState; onLoggedOut: () =>
     return () => events.close();
   }, [refresh]);
 
+  useEffect(() => {
+    const syncPageWithLocation = () => setPage(pageFromLocation());
+    window.addEventListener("hashchange", syncPageWithLocation);
+    return () => window.removeEventListener("hashchange", syncPageWithLocation);
+  }, []);
+
+  function navigate(nextPage: DashboardPage) {
+    setPage(nextPage);
+    window.location.hash = `/${nextPage}`;
+  }
+
   async function logout() {
     await post("/api/auth/logout", {}, auth.csrfToken);
     await onLoggedOut();
@@ -212,11 +231,11 @@ function Dashboard({ auth, onLoggedOut }: { auth: AuthState; onLoggedOut: () =>
       <aside className="sidebar">
         <div className="brand brand-compact"><Gauge size={30} weight="duotone" /><span>Pi Companion</span></div>
         <nav aria-label="Primary navigation">
-          <button className={`nav-item ${page === "home" ? "active" : ""}`} onClick={() => setPage("home")}><House size={24} weight={page === "home" ? "fill" : "regular"} /><span>Home</span></button>
-          <button className={`nav-item ${page === "car" ? "active" : ""}`} onClick={() => setPage("car")}><CarProfile size={24} weight={page === "car" ? "fill" : "regular"} /><span>Car</span></button>
-          <button className={`nav-item ${page === "adb" ? "active" : ""}`} onClick={() => setPage("adb")}><AndroidLogo size={24} weight={page === "adb" ? "fill" : "regular"} /><span>ADB</span></button>
-          <button className={`nav-item ${page === "network" ? "active" : ""}`} onClick={() => setPage("network")}><WifiHigh size={24} weight={page === "network" ? "fill" : "regular"} /><span>Network</span></button>
-          <button className={`nav-item ${page === "settings" ? "active" : ""}`} onClick={() => setPage("settings")}><Gear size={24} weight={page === "settings" ? "fill" : "regular"} /><span>Settings</span></button>
+          <button className={`nav-item ${page === "home" ? "active" : ""}`} onClick={() => navigate("home")}><House size={24} weight={page === "home" ? "fill" : "regular"} /><span>Home</span></button>
+          <button className={`nav-item ${page === "car" ? "active" : ""}`} onClick={() => navigate("car")}><CarProfile size={24} weight={page === "car" ? "fill" : "regular"} /><span>Car</span></button>
+          <button className={`nav-item ${page === "adb" ? "active" : ""}`} onClick={() => navigate("adb")}><AndroidLogo size={24} weight={page === "adb" ? "fill" : "regular"} /><span>ADB</span></button>
+          <button className={`nav-item ${page === "network" ? "active" : ""}`} onClick={() => navigate("network")}><WifiHigh size={24} weight={page === "network" ? "fill" : "regular"} /><span>Network</span></button>
+          <button className={`nav-item ${page === "settings" ? "active" : ""}`} onClick={() => navigate("settings")}><Gear size={24} weight={page === "settings" ? "fill" : "regular"} /><span>Settings</span></button>
         </nav>
         <button className="nav-item logout" onClick={() => void logout()}><SignOut size={24} /><span>Sign out</span></button>
       </aside>