# Audit: Migrating from `userId` to `workspaceId`

This document audits every place the project uses `userId` (and `user_id`) so the
migration to a `workspaceId`-scoped model can be done completely. There are
currently **no references to `workspaceId`** anywhere in the codebase — this is a
greenfield rename/replacement.

## How scoping currently works (the mental model)

1. **Source of truth set at login** — `login_controller.dart:70` stores
   `prefs.setString('userId', response['uuid'])`. The backend's `uuid` becomes
   the locally cached `userId`.
2. **Anonymous fallback** — `home_screen.dart:127,162` generate a random
   `Uuid().v4()` and store it as `userId` when none exists (anonymous/guest flow).
3. **Consumption** — Almost everywhere else reads `prefs.getString("userId")`
   and passes it to the backend as:
   - a **query param** (`?userId=...` or `_queryParams['userId']`),
   - a **request body field** (`BatchActionRequest.userId`, `FormData.userId`),
   - a **model field** deserialized from `json['userId']`.

> Migration decision needed (see "Open questions"): is `workspaceId` a NEW value
> the backend returns at login, or simply a rename of the existing `uuid`? And
> will the API now accept/scope by a header (e.g. `X-Workspace-Id`) instead of a
> query param? The plan below assumes a rename + the option to centralize scoping.

---

## Inventory of changes required

### A. Persistence / key name (the keystone)

The SharedPreferences key string `"userId"` is the single most important thing to
change consistently. If the key string is changed in one place but not another,
reads will silently return `null`.

| File | Line | Current | Action |
|---|---|---|---|
| `lib/screens/onboarding/login/login_controller.dart` | 70 | `prefs.setString('userId', response['uuid'])` | Write `workspaceId`. Confirm backend field — may become `response['workspaceId']`. |
| `lib/screens/home/home_screen.dart` | 127, 162 | `prefs.setString("userId", Uuid().v4())` | Rename key to `workspaceId` (anonymous fallback). |
| `lib/screens/home/home_screen.dart` | 126, 130, 151, 152, 161, 165 | `prefs.getString("userId")` | Rename key reads to `workspaceId`. |
| `lib/screens/onboarding/phone/phone_controller.dart` | 48 | `"tempUid": prefs.get("userId")` | Rename key read; confirm whether `tempUid` body field name should change too. |

> Recommendation: introduce a single constant, e.g. `const kWorkspaceIdKey = 'workspaceId';`
> and a small helper (`Prefs.workspaceId`) so the key string is never duplicated again.
> A migration shim should also copy any existing `userId` value to `workspaceId` on
> first launch so logged-in users aren't logged out.

### B. Query-param / URL usages (sent to backend)

| File | Line | Current |
|---|---|---|
| `lib/screens/recipient/recipients_screen.dart` | 69, 271 | `_queryParams['userId'] = prefs.getString("userId")!` |
| `lib/screens/history/history_controller.dart` | 119, 146 | `'userId': userId` (query map) |
| `lib/screens/groups/controllers/group_controller.dart` | 72, 197, 233, 269 | `'userId': userId` and `?userId=$userId` in URLs |
| `lib/screens/groups/controllers/batch_controller.dart` | 369, 528, 584 | `?userId=$userId` in URLs |
| `lib/screens/home/home_controller.dart` | 158 | `...&userId=$userId` in URL |

Action: rename the param key to `workspaceId` (or move scoping into a header — see C).

### C. HTTP layer (`lib/http/http.dart`)

Currently the HTTP wrapper only adds `Authorization: Bearer <token>` headers
(`getHeaders()` around lines 28–36). It does **not** know about `userId`.

Action / opportunity: if the backend now scopes by a workspace header, this is the
single best place to inject `X-Workspace-Id` once, eliminating the dozens of
per-call query params. Otherwise, leave the per-call params and just rename them.

### D. Request-body model fields & method params (Dart-side, hand-written)

These are the hand-written declarations and call sites to rename
(`userId` -> `workspaceId`):

- `lib/screens/groups/models/group_batch_model.dart` — fields at lines 9, 90, 117, 134 and constructors 26, 100, 121, 141 (includes `BatchActionRequest.userId`).
- `lib/screens/groups/models/recipient_group_model.dart` — fields 11, 33, 58 and constructors 18, 42, 64.
- `lib/screens/groups/models/batch_item_update_model.dart` — field 38, constructor 40.
- `lib/screens/transactions/transaction_model.dart` — field 53, constructor 101.
- `lib/screens/transaction_controller.dart` — defaults/params 41, 71, 152 (the freezed `FormData.userId`).
- `lib/screens/groups/controllers/group_controller.dart` — method params 56, 118, 123, 193, 229, 244, 257 and internal calls 120, 128, 251.
- `lib/screens/groups/controllers/batch_controller.dart` — method params 363, 466, 494, 522, 545, 581, 598 and `BatchActionRequest(userId: ...)` at 473, 501, 552; recursive call 606.
- `lib/screens/history/history_controller.dart` — method params 110, 141.
- `lib/screens/home/home_controller.dart` — method param 151.

### E. Call sites in screens (read prefs -> pass through)

- `lib/screens/pay/pay_controller.dart` — 101 (`userId: prefs.getString("userId") ?? ''` into FormData).
- `lib/screens/groups/screens/group_create_screen.dart` — 84, 91.
- `lib/screens/groups/screens/group_detail_screen.dart` — 555, 678, 703 (`widget.group.userId`).
- `lib/screens/groups/screens/batch_detail_screen.dart` — local `_userId` at 36, 88 and uses at 90, 139, 155, 434, 487, 675, 688, 1438.
- `lib/screens/groups/screens/create_group_from_file_screen.dart` — 68, 72.
- `lib/screens/groups/screens/groups_screen.dart` — 33, 39, 40, 44, 46, 52, 75.
- `lib/screens/groups/screens/batch_create_screen.dart` — 92, 96, 118, 133, 157.
- `lib/screens/history/history_screen.dart` — 67, 74, 230, 330, 354, 499, 512.

### F. Generated files (DO NOT hand-edit — regenerate)

These contain `userId` derived from `@JsonKey`/freezed annotations in the
hand-written sources above. After renaming the source fields (and the JSON keys),
regenerate with build_runner:

- `lib/screens/transaction_controller.g.dart`
- `lib/screens/transaction_controller.freezed.dart`
- `lib/screens/groups/models/batch_item_update_model.g.dart`
- `lib/screens/groups/models/recipient_group_model.g.dart`
- `lib/screens/groups/models/group_batch_model.g.dart`
- `lib/screens/transactions/transaction_model.g.dart`

Regenerate command:
```
dart run build_runner build --delete-conflicting-outputs
```

---

## JSON wire-key decision (critical)

The generated serializers currently read/write the JSON key `'userId'`
(e.g. `json['userId']`, `'userId': instance.userId`). You must decide whether the
**backend JSON contract** also changes to `workspaceId`:

- If the API now expects/returns `workspaceId`: rename the Dart field AND let the
  serializer use the new key (or add `@JsonKey(name: 'workspaceId')`).
- If the API still uses `userId` on the wire but you only want the Dart field
  renamed: keep the wire key with `@JsonKey(name: 'userId')` on the renamed field.

This must be coordinated with the backend team before regenerating.

---

## Recommended migration order

1. Confirm backend contract (see Open questions) — header vs query param, and the
   JSON key name.
2. Add a `kWorkspaceIdKey` constant + prefs helper, plus a one-time migration shim
   that copies existing `userId` -> `workspaceId`.
3. (Optional but recommended) Inject `X-Workspace-Id` centrally in `http.dart`.
4. Rename hand-written model fields / method params (sections D & E).
5. Update query-param/URL usages (section B), or remove them if moved to header.
6. Update the prefs key reads/writes (section A).
7. Regenerate build_runner outputs (section F).
8. `flutter analyze` and test the anonymous flow, login flow, history, groups,
   batches, recipients, and pay flows end-to-end.

## Open questions for the team

- Is `workspaceId` a brand-new value from the backend (e.g. `response['workspaceId']`),
  or just a rename of the existing `uuid`/`userId`?
- Should scoping move to a request **header** (`X-Workspace-Id`) so it can be set
  once in `http.dart`, instead of ~15 per-call query params/body fields?
- Does the JSON wire contract change to `workspaceId`, or stay `userId`?
- For the anonymous/guest flow (`home_screen.dart`), is a client-generated
  `Uuid().v4()` still acceptable as a `workspaceId`, or must the backend mint it?
- Does `phone_controller`'s `tempUid` body key need renaming too?

## Summary counts

- Non-generated `.dart` files to edit: **21**
- Generated files to regenerate: **6**
- Total non-generated `userId`/`user_id` occurrences: **~112**
- Existing `workspaceId` references: **0**
