# Code standardization & modernization review (2026-07-06)

A grounded pass over the Android app (313 Kotlin files), Cloud Functions (TypeScript), and build. Each
item is a *real, measured* inconsistency (with counts), not generic advice.

## Applied (done + verified)

1. **Compose state collection unified on `collectAsStateWithLifecycle`** — was 55 files on
   `collectAsState()` vs 2 lifecycle-aware; now all 57. Added `lifecycle-runtime-compose`. Upstream
   flow collection pauses when the UI isn't visible.
2. **Firebase Tasks → `.await()` across the ENTIRE data layer** — all 15 data sources converted from
   verbose `suspendCancellableCoroutine{cont-> …addOnSuccess/addOnFailure}` wrappers (and the per-file
   `getDoc`/`voidAwait`/`queryAwait`/`refAwait` helper duplicates) to `kotlinx-coroutines-play-services`
   `.await()`. Zero Task-callback wrappers remain. Per-block review kept `callbackFlow` snapshot
   listeners + the one transaction untouched; failure→null/false best-effort blocks became
   `runCatching{…await()}.getOrNull()/getOrDefault()`; no-signed-in-user guards became `?: throw`.
   **Verified live** (real Firebase, paired account): auth + Home reads and a daily-answer write all
   succeed.
3. **Gradle version catalog (`gradle/libs.versions.toml`)** — 57 hardcoded coordinates centralized;
   root + app scripts use `libs.*` / `alias(libs.plugins.*)`. 1:1, no version changes.
4. **Typed Cloud Functions callable payloads** — the 5 `onCall((data: any, …))` handlers now take
   `Record<string, unknown>`, forcing field access through the existing validators.
5. **ViewModels off Firebase (7 of 8 offenders):**
   - 5 VMs (BucketList, QuestionThread, DateBuilder, MessagesInbox, Conversation) switched from the
     `FirebaseAuth.getInstance()` static singleton to the injected `AuthRepository.currentUserId`.
   - 2 VMs (DailyQuestion, PartnerHome) had their raw `db.…addSnapshotListener` on the partner's answer
     doc replaced with the existing `FirestoreAnswerDataSource.observeAnswerForUser(...)` Flow (Job-managed),
     dropping the `FirebaseFirestore` injection. Verified live (correct "waiting for partner" state).

## Remaining — scoped, deliberate follow-ons (NOT churn-avoidance)

6. **HomeViewModel's two snapshot listeners** — the last raw-Firestore-in-VM. Deliberately left because,
   unlike the two extracted above, these use `MetadataChanges.INCLUDE` (fire on local/pending writes, not
   just server data) and carry inline partner-answered analytics + widget-state updates, and they drive
   the app's **core reveal trigger**. Doing this right needs a metadata-aware data-source Flow AND
   **two-device** real-time verification (partner answers on device B → device A flips to reveal) — a
   single-device smoke can't catch a regression here. Extract as its own focused task.
7. **~175 hardcoded `Color(0xFF…)` in `ui/`** → theme tokens. Right modern practice, but visual-
   regression risk; pair with `scripts/theme-scan.sh` + screenshot diffs, per-screen (not en masse).
8. **Cloud Functions v1 → v2** (`firebase-functions/v2/*`). The modern target (cold-start/concurrency/
   typed params), but changes signatures + deploy config and touches the billing webhook / callables —
   its own project with sandbox verification, not bundled.
9. **`catch (err: any)` → `unknown`** narrowing and the untyped Tink handles in `wrapReleaseKeyCallable`
   (the crypto lib ships no types) — marginal value; fold into #8 if/when it happens.

## Healthy already (no action)

Material3 only (86 files, zero Material2); no `GlobalScope`; only 9 `!!` app-wide; analytics hashing
single-sourced. DI split of `@Binds`/`@Provides` is idiomatic.

## Verdict

The safe, high-value standardizations are done and verified (state collection, the whole data-layer
Tasks→await, version catalog, TS payload typing, 7/8 ViewModel-Firebase extractions). The four
remaining items are each a case where a responsible change needs its own verification loop
(two-device real-time, screenshot diffs, or a sandbox deploy) rather than a broad sweep — sequenced
6 → 8 → 7 → 9.