🕵️ Impostor

A party word game for React Native (Expo). Everyone gets the same secret word — except the impostor. Describe the word without saying it, then vote out the liar.

Two ways to play:

• Pass & Play — one phone, no setup, works offline.
• Online — create a room, friends join with a 4-letter code (needs Firebase).

Run it

npm install
npm run start        # scan the QR code with Expo Go (iOS/Android)

Pass & Play works immediately. Online mode needs Firebase (below).

Firebase setup (online mode)

This app runs in Expo Go, so it uses the Firebase JS web SDK — do not install @react-native-firebase/* (native modules won't load in Expo Go).

1. Create a project at console.firebase.google.com.
2. Add a Web app (</> icon) and copy the SDK config values.
3. Build → Authentication → Sign-in method → enable Anonymous.
4. Build → Realtime Database → create a database, then paste the contents of database.rules.json into the Rules tab.
5. cp .env.example .env, fill in the values, restart the dev server (npm run start -- --clear).

The anonymous auth UID is persisted in AsyncStorage, so players who close the app can rejoin the same room code and pick up where they left off ("Rejoin last room" on the online screen).

Google sign-in (optional profile)

Players can attach a Google account (name + avatar) on the home screen. It links onto the anonymous session, so the game UID — and any in-progress room — is kept.

1. Firebase console → Authentication → Sign-in method → enable Google. Copy the Web client ID shown in the provider panel into EXPO_PUBLIC_GOOGLE_WEB_CLIENT_ID.
2. Google Cloud console (same project) → Create OAuth client ID → Android:
   • Package name: com.imnb57.impostor
   • SHA-1: from npx eas-cli credentials (Android → your keystore) Put the resulting ID in EXPO_PUBLIC_GOOGLE_ANDROID_CLIENT_ID.

Note: Google sign-in only works in a built app (APK/AAB or dev build) — the button is disabled inside Expo Go, where the app's OAuth redirect scheme doesn't exist. Everything else works in Expo Go.

Build an APK to share (EAS)

npm install -g eas-cli        # or use npx eas-cli
eas login                     # your Expo account
eas init                      # links the project (creates the EAS project id)
eas env:create --scope project   # add every EXPO_PUBLIC_* var for the
                                  # "preview" and "production" environments —
                                  # .env is gitignored and never uploaded
eas build -p android --profile preview

The preview profile produces an installable .apk you can send to anyone (they must enable "install unknown apps"). Build status and the download link appear at expo.dev.

Play Store checklist

1. eas build -p android --profile production → produces an .aab.
2. Play Console: create the app, upload the .aab to Internal testing first.
3. eas submit -p android can automate uploads once you add a service account key.
4. Required before review:
   • App icons/splash: replace the placeholder images in assets/.
   • Privacy policy URL — required because the app uses Firebase Auth (Google sign-in collects name/email/photo; anonymous auth stores a device identifier).
   • Data safety form: declare Firebase Auth (identifiers, name, email) and Realtime Database (player names, votes) collection.
   • Content rating questionnaire (this app: no user-generated chat, no ads yet).
5. Package name com.imnb57.impostor is set in app.json — change it before the first Play upload if you want a different one; it's permanent afterwards.
6. Deploy database.rules.json to Realtime Database rules (console → Rules tab) — test mode expires and leaves the DB open.

Pushing updates without a reinstall (EAS Update)

Installed apps pull JavaScript and asset changes over the air, so most changes reach players without them downloading a new APK.

# ship whatever is in the working tree to everyone on the preview APK
eas update --branch preview --message "fix voting copy"

Players get it on next launch (the app checks automatically), or immediately via Settings → Check for updates.

What can and cannot travel this way — this is the part that bites:

Change	Ships over the air?
Screens, copy, styling, game logic, word bank	✅ yes
New JS dependency (no native code)	✅ yes
New native module (expo install something with native code)	❌ new APK
Anything in app.json native config — icons, splash, permissions, package	❌ new APK
Bumping version in app.json	❌ breaks the update link — see below

runtimeVersion uses the appVersion policy, meaning an update only reaches builds with a matching version. Leave version alone while shipping OTA fixes. When you do need a native change, bump version, build a new APK, and publish updates against that version from then on.

First release on a new version:

eas build -p android --profile preview   # players install this once
eas update --branch preview -m "..."     # then every fix flows automatically

Game modes

Mode	What changes
Classic	Everyone knows the word; the impostor gets one oblique clue.
Saboteur	One player knows the word but wins only if an innocent is voted out.
Informant	One player learns an impostor's name but never the word. If the impostor is caught, they get one shot at naming the informant to steal the round.
Fragments	Nobody gets the word — each player holds a different facet of it, and the impostor's facet belongs to a different word entirely.

Roles, payloads and win conditions live in src/services/roles.ts and src/services/resolveRound.ts. resolveRound is pure and fully tested (npm test) because a subtle bug there silently ruins games.

Scripts

Command	What it does
npm run start	Start the Expo dev server
npm run android / npm run ios	Start and open on a device/simulator
npm run typecheck	TypeScript check (tsc --noEmit)

Project layout

See Claude.md for the full spec. Short version: screens are thin, game logic lives in src/services, Firebase access only goes through src/services/rooms.ts, and every online screen renders from a single Realtime Database subscription mirrored in src/store/roomStore.ts.