debug(auth): log session cookie source

apps/web/src/app/(auth)/login/page.mock-mode.test.tsx

@@ -0,0 +1,87 @@
+import { describe, it, expect, vi, beforeEach, type Mock } from "vitest";
+import { render, screen, waitFor } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import LoginPage from "./page";
+
+const { mockPush, mockReplace, mockSearchParams, authState } = vi.hoisted(() => ({
+  mockPush: vi.fn(),
+  mockReplace: vi.fn(),
+  mockSearchParams: new URLSearchParams(),
+  authState: {
+    isAuthenticated: false,
+    refreshSession: vi.fn(),
+  },
+}));
+
+const { mockFetchWithRetry } = vi.hoisted(() => ({
+  mockFetchWithRetry: vi.fn(),
+}));
+
+vi.mock("next/navigation", () => ({
+  useRouter: (): { push: Mock; replace: Mock } => ({
+    push: mockPush,
+    replace: mockReplace,
+  }),
+  useSearchParams: (): URLSearchParams => mockSearchParams,
+}));
+
+vi.mock("@/lib/config", () => ({
+  API_BASE_URL: "http://localhost:3001",
+  IS_MOCK_AUTH_MODE: true,
+}));
+
+vi.mock("@/lib/auth-client", () => ({
+  signIn: {
+    oauth2: vi.fn(),
+    email: vi.fn(),
+  },
+}));
+
+vi.mock("@/lib/auth/auth-context", () => ({
+  useAuth: (): { isAuthenticated: boolean; refreshSession: Mock } => ({
+    isAuthenticated: authState.isAuthenticated,
+    refreshSession: authState.refreshSession,
+  }),
+}));
+
+vi.mock("@/lib/auth/fetch-with-retry", () => ({
+  fetchWithRetry: mockFetchWithRetry,
+}));
+
+describe("LoginPage (mock auth mode)", (): void => {
+  beforeEach((): void => {
+    vi.clearAllMocks();
+    mockSearchParams.delete("error");
+    authState.isAuthenticated = false;
+    authState.refreshSession.mockResolvedValue(undefined);
+  });
+
+  it("should render mock auth controls", (): void => {
+    render(<LoginPage />);
+
+    expect(screen.getByText(/local mock auth mode is active/i)).toBeInTheDocument();
+    expect(screen.getByTestId("mock-auth-login")).toBeInTheDocument();
+    expect(mockFetchWithRetry).not.toHaveBeenCalled();
+  });
+
+  it("should continue with mock session and navigate to tasks", async (): Promise<void> => {
+    const user = userEvent.setup();
+    render(<LoginPage />);
+
+    await user.click(screen.getByTestId("mock-auth-login"));
+
+    await waitFor(() => {
+      expect(authState.refreshSession).toHaveBeenCalledTimes(1);
+      expect(mockPush).toHaveBeenCalledWith("/tasks");
+    });
+  });
+
+  it("should auto-redirect authenticated mock users to tasks", async (): Promise<void> => {
+    authState.isAuthenticated = true;
+    render(<LoginPage />);
+
+    await waitFor(() => {
+      expect(mockReplace).toHaveBeenCalledWith("/tasks");
+    });
+  });
+});

apps/web/src/app/(auth)/login/page.test.tsx

@@ -16,6 +16,11 @@ const { mockOAuth2, mockSignInEmail, mockPush, mockReplace, mockSearchParams } =
   mockSearchParams: new URLSearchParams(),
 }));
 
+const { mockRefreshSession, mockIsAuthenticated } = vi.hoisted(() => ({
+  mockRefreshSession: vi.fn(),
+  mockIsAuthenticated: false,
+}));
+
 vi.mock("next/navigation", () => ({
   useRouter: (): { push: Mock; replace: Mock } => ({
     push: mockPush,
@@ -33,6 +38,14 @@ vi.mock("@/lib/auth-client", () => ({
 
 vi.mock("@/lib/config", () => ({
   API_BASE_URL: "http://localhost:3001",
+  IS_MOCK_AUTH_MODE: false,
+}));
+
+vi.mock("@/lib/auth/auth-context", () => ({
+  useAuth: (): { isAuthenticated: boolean; refreshSession: Mock } => ({
+    isAuthenticated: mockIsAuthenticated,
+    refreshSession: mockRefreshSession,
+  }),
 }));
 
 // Mock fetchWithRetry to behave like fetch for test purposes
@@ -91,6 +104,7 @@ describe("LoginPage", (): void => {
     mockSearchParams.delete("error");
     // Default: OAuth2 returns a resolved promise (fire-and-forget redirect)
     mockOAuth2.mockResolvedValue(undefined);
+    mockRefreshSession.mockResolvedValue(undefined);
   });
 
   it("renders loading state initially", (): void => {

apps/web/src/app/(auth)/login/page.tsx

@@ -5,10 +5,11 @@ import type { ReactElement } from "react";
 import { useRouter, useSearchParams } from "next/navigation";
 import { Loader2 } from "lucide-react";
 import type { AuthConfigResponse, AuthProviderConfig } from "@mosaic/shared";
-import { API_BASE_URL } from "@/lib/config";
+import { API_BASE_URL, IS_MOCK_AUTH_MODE } from "@/lib/config";
 import { signIn } from "@/lib/auth-client";
 import { fetchWithRetry } from "@/lib/auth/fetch-with-retry";
 import { parseAuthError } from "@/lib/auth/auth-errors";
+import { useAuth } from "@/lib/auth/auth-context";
 import { OAuthButton } from "@/components/auth/OAuthButton";
 import { LoginForm } from "@/components/auth/LoginForm";
 import { AuthDivider } from "@/components/auth/AuthDivider";
@@ -45,6 +46,7 @@ export default function LoginPage(): ReactElement {
 function LoginPageContent(): ReactElement {
   const router = useRouter();
   const searchParams = useSearchParams();
+  const { isAuthenticated, refreshSession } = useAuth();
   const [config, setConfig] = useState<AuthConfigResponse | null | undefined>(undefined);
   const [loadingConfig, setLoadingConfig] = useState(true);
   const [retryCount, setRetryCount] = useState(0);
@@ -68,6 +70,18 @@ function LoginPageContent(): ReactElement {
   }, [searchParams, router]);
 
   useEffect(() => {
+    if (IS_MOCK_AUTH_MODE && isAuthenticated) {
+      router.replace("/tasks");
+    }
+  }, [isAuthenticated, router]);
+
+  useEffect(() => {
+    if (IS_MOCK_AUTH_MODE) {
+      setConfig({ providers: [] });
+      setLoadingConfig(false);
+      return;
+    }
+
     let cancelled = false;
 
     async function fetchConfig(): Promise<void> {
@@ -158,6 +172,48 @@ function LoginPageContent(): ReactElement {
     setRetryCount((c) => c + 1);
   }, []);
 
+  const handleMockLogin = useCallback(async (): Promise<void> => {
+    setError(null);
+    try {
+      await refreshSession();
+      router.push("/tasks");
+    } catch (err: unknown) {
+      const parsed = parseAuthError(err);
+      setError(parsed.message);
+    }
+  }, [refreshSession, router]);
+
+  if (IS_MOCK_AUTH_MODE) {
+    return (
+      <main className="flex min-h-screen flex-col items-center justify-center p-4 sm:p-8 bg-gray-50">
+        <div className="w-full max-w-md space-y-8">
+          <div className="text-center">
+            <h1 className="text-2xl sm:text-4xl font-bold mb-4">Welcome to Mosaic Stack</h1>
+            <p className="text-base sm:text-lg text-gray-600">
+              Local mock auth mode is active. Real sign-in is bypassed for frontend development.
+            </p>
+          </div>
+          <div className="bg-white p-4 sm:p-8 rounded-lg shadow-md space-y-4">
+            <div className="rounded-md border border-amber-300 bg-amber-50 p-3 text-sm text-amber-900">
+              Mock auth mode is local-only and blocked outside development.
+            </div>
+            {error && <AuthErrorBanner message={error} />}
+            <button
+              type="button"
+              onClick={() => {
+                void handleMockLogin();
+              }}
+              className="w-full rounded-md bg-blue-600 px-4 py-2 text-sm font-medium text-white hover:bg-blue-700 transition-colors"
+              data-testid="mock-auth-login"
+            >
+              Continue with Mock Session
+            </button>
+          </div>
+        </div>
+      </main>
+    );
+  }
+
   return (
     <main className="flex min-h-screen flex-col items-center justify-center p-4 sm:p-8 bg-gray-50">
       <div className="w-full max-w-md space-y-8">

apps/web/src/app/(authenticated)/layout.tsx

@@ -3,6 +3,7 @@
 import { useEffect } from "react";
 import { useRouter } from "next/navigation";
 import { useAuth } from "@/lib/auth/auth-context";
+import { IS_MOCK_AUTH_MODE } from "@/lib/config";
 import { Navigation } from "@/components/layout/Navigation";
 import { ChatOverlay } from "@/components/chat";
 import type { ReactNode } from "react";
@@ -36,8 +37,18 @@ export default function AuthenticatedLayout({
   return (
     <div className="min-h-screen bg-gray-50">
       <Navigation />
-      <div className="pt-16">{children}</div>
-      <ChatOverlay />
+      <div className="pt-16">
+        {IS_MOCK_AUTH_MODE && (
+          <div
+            className="border-b border-amber-300 bg-amber-50 px-4 py-2 text-sm text-amber-900"
+            data-testid="mock-auth-banner"
+          >
+            Mock Auth Mode (Local Only): Real authentication is bypassed for frontend development.
+          </div>
+        )}
+        {children}
+      </div>
+      {!IS_MOCK_AUTH_MODE && <ChatOverlay />}
     </div>
   );
 }