fix(dashboard): redirect authenticated login visits

apps/dashboard/app/login/page.tsx

@@ -1,19 +1,33 @@
+import { headers } from "next/headers";
+import { redirect } from "next/navigation";
 import { LoginForm } from "./login-form";
 import {
   Card,
   CardContent,
   CardHeader,
 } from "@/components/ui/card";
 import { BrandLogo } from "@/components/brand-logo";
+import { auth } from "@/lib/auth";
 import { getBranding } from "@/lib/branding-server";
-import { safeCallbackPath } from "@/lib/safe-callback-path";
+import {
+  DEFAULT_CALLBACK_PATH,
+  safeCallbackPath,
+} from "@/lib/safe-callback-path";
 
 export default async function Login({
   searchParams,
 }: {
   searchParams: Promise<{ callbackURL?: string }>;
 }) {
   const { callbackURL } = await searchParams;
+  const callbackPath = safeCallbackPath(callbackURL);
+  const session = await auth.api.getSession({ headers: await headers() });
+  if (session) {
+    redirect(
+      callbackPath === "/login" ? DEFAULT_CALLBACK_PATH : callbackPath,
+    );
+  }
+
   const branding = await getBranding();
   return (
     <main className="grid min-h-svh place-items-center bg-background p-4">
@@ -22,7 +36,7 @@ export default async function Login({
           <BrandLogo url={branding.logo_url} placement="login" />
         </CardHeader>
         <CardContent>
-          <LoginForm callbackURL={safeCallbackPath(callbackURL)} />
+          <LoginForm callbackURL={callbackPath} />
         </CardContent>
       </Card>
     </main>

tests/e2e/specs/journey.spec.ts

@@ -161,6 +161,18 @@ test.describe.serial("Blue deployment journey", () => {
     expect(refreshedClaims.aud).toBeTruthy();
   });
 
+  test("@smoke authenticated users are redirected away from login", async ({ page }) => {
+    await loginAsAdmin(page);
+
+    await page.goto("/login", { waitUntil: "commit" });
+    await expect(page).toHaveURL(/\/sessions$/);
+    await expect(page.getByLabel("Email")).toHaveCount(0);
+
+    await page.goto("/login?callbackURL=%2Fgateway", { waitUntil: "commit" });
+    await expect(page).toHaveURL(/\/gateway$/);
+    await expect(page.getByLabel("Email")).toHaveCount(0);
+  });
+
   test("@smoke executable provisioner creates managed gateway access", async () => {
     const result = await runCli(home, ["gateway"]);
     expect(result.code, result.stderr).toBe(0);