SETUP.md

1. Why We Use the Emulator The Firebase Emulator allows you to:

   Develop without touching production data. Test Firestore locally.

   Use mocked authentication (but with limitations).

   ⚠️ Current Limitation

   🔴 Google Sign-In does NOT work with the Firebase Auth Emulator. The emulator does not support real OAuth flows (Google, Facebook, etc.). Popups will fail with auth/popup-closed-by-user.

   For this reason, the Auth Emulator is currently disabled in our local setup.

   We use real Google login in dev mode until a mock/fake login flow is implemented.

2. What is Enabled in Dev Mode Firestore Emulator ✅ (port 8080) Storage Emulator ✅ (if needed) Auth Emulator ❌ (disabled because Google OAuth cannot be used)

3. How to Run Locally Install Firebase CLI:

   bash
   npm install -g firebase-tools
   firebase emulators:start --only firestore,storage
   

   Run the Next.js dev server:

   bash
   npm run dev
   

4. Switching Between Emulator and Production We control emulator usage via .env.local:

   NEXT_PUBLIC_FIREBASE_USE_EMULATOR=false

   false → Uses real Firebase (with Google login).

   true → Would connect to emulator, but Auth Emulator is skipped.

5. Firebase Config Behavior If NEXT_PUBLIC_FIREBASE_USE_EMULATOR=true → Firestore connects to local emulator. Auth Emulator is intentionally not connected because Google login would fail. You can still test other auth methods (email/password) by manually enabling it.

6. Adding Back Auth Emulator (Optional) If you later implement fake Google login for dev: Uncomment the connectAuthEmulator line in firebaseConfig.js. Use a mock Google credential for sign-in.

   Example:

   import { GoogleAuthProvider, signInWithCredential } from "firebase/ auth";
   const fakeCredential = GoogleAuthProvider.credential(
     '{"sub":"1234567890","email":"testuser@gmail.com",    "email_verified":true}'
   );
   await signInWithCredential(auth, fakeCredential);