# Budget Site — Implementation Plan

## Overview

Replace a Google Docs spreadsheet with a multi-user budget web app. Users get Income, Outgo, and Summary views organized around the 50/30/20 framework. Budgets can be shared with other users in edit or view-only mode.

**Stack:**
- Backend: ASP.NET Core (serves API + hosts compiled React assets)
- Frontend: Vite + React (TypeScript)
- Database: PostgreSQL via EF Core
- Auth: OIDC against `auth.stwaddle.com` (OpenIddict-based)
- Deployment: Single Docker container (no nginx needed)

---

## Frequency Reference

All monetary amounts are normalized to monthly and annual values using these multipliers:

| Frequency     | Monthly Multiplier        | Notes                           |
|---------------|---------------------------|---------------------------------|
| Biennial      | amount / 24               | Once every 2 years              |
| Annually      | amount / 12               | Once per year                   |
| Biannually    | amount × 2 / 12           | Twice per year                  |
| Quarterly     | amount × 4 / 12           | 4× per year                     |
| Every 2 Months| amount × 6 / 12           | Every other month (6× per year) |
| Monthly       | amount × 1                |                                 |
| Semi-monthly  | amount × 2                | Twice per month                 |
| Biweekly      | amount × 26 / 12          | Every 2 weeks                   |
| Weekly        | amount × 52 / 12          | Every week                      |

---

## Architecture

### Single-Container Strategy

The ASP.NET Core app serves the Vite production build from its `wwwroot` directory. The Dockerfile is a two-stage build:

1. **Stage 1 (node):** `npm run build` inside `client/` → outputs to `client/dist/`
2. **Stage 2 (dotnet):** Publishes the ASP.NET app, copies `client/dist` into `wwwroot/`

At runtime, ASP.NET uses `UseStaticFiles()` + a catch-all fallback route that returns `index.html` for any non-API path (SPA fallback). API routes are prefixed `/api`.

### Development Mode

In development the Vite dev server runs separately (e.g., `localhost:5173`). ASP.NET proxies unknown routes to it via `Microsoft.AspNetCore.SpaProxy` or a simple reverse proxy middleware. A `launchSettings.json` profile wires this up so `dotnet run` and `npm run dev` together give hot-reload on both sides.

### Project Layout

```
Budget.sln
├── src/
│   ├── Budget.Api/              # ASP.NET Core project
│   │   ├── Controllers/
│   │   ├── Data/                # EF Core DbContext, migrations
│   │   ├── Models/              # EF Core entities
│   │   ├── DTOs/                # Request/response shapes
│   │   ├── Services/            # Business logic
│   │   ├── wwwroot/             # Populated by Docker build stage
│   │   └── Program.cs
│   └── Budget.Client/           # Vite + React project
│       ├── src/
│       │   ├── pages/           # Income, Outgo, Summary
│       │   ├── components/
│       │   ├── api/             # API client (fetch wrappers)
│       │   ├── hooks/
│       │   └── types/
│       ├── index.html
│       ├── vite.config.ts
│       └── package.json
├── Dockerfile
├── docker-compose.yml           # User maintains this separately
├── .env.example
└── .plans/
```

---

## Data Model

### Entities

**Budget**
- `Id` (Guid)
- `Name` (string)
- `OwnerUserId` (string — `sub` claim from OIDC token)
- `CreatedAt`, `UpdatedAt`

**Income**
- `Id` (Guid)
- `BudgetId` (Guid, FK)
- `Name` (string)
- `Frequency` (enum)
- `Amount` (decimal)
- `SortOrder` (int) — preserves user-defined row ordering

**Outgo**
- `Id` (Guid)
- `BudgetId` (Guid, FK)
- `Name` (string)
- `Category` (string, nullable)
- `Type` (enum: Need | Want | Save)
- `Frequency` (enum)
- `Amount` (decimal)
- `PaymentSource` (string, nullable)
- `Notes` (string, nullable)
- `SortOrder` (int)

> `Monthly`, `Annually`, and `MonthlyPercentage` are computed — not stored. The API returns them as calculated fields in DTOs.

**KnownUser** *(local cache of authenticated users)*
- `Id` (string — the OIDC `sub` claim, PK)
- `Email` (string)
- `Name` (string)
- `LastSeenAt` (DateTimeOffset)

> Populated/updated each time a user authenticates with the Budget app. Used for the share-by-email lookup flow without requiring any changes to the Auth server.

**BudgetShare**
- `Id` (Guid)
- `BudgetId` (Guid, FK)
- `SharedWithUserId` (string, nullable) — null until the target user has logged in
- `SharedWithEmail` (string) — the email used when the share was created; used to resolve pending shares on login
- `Permission` (enum: View | Edit)
- `IsPending` (bool) — true when `SharedWithUserId` is null
- `CreatedAt`

> When a user authenticates, the app queries for pending shares where `SharedWithEmail` matches their token's `email` claim, sets `SharedWithUserId` and clears `IsPending`. This allows pre-sharing with users who haven't logged in yet without any Auth server changes or enumeration risk.

### Authorization Rules

- Only the budget owner or a user with Edit permission may mutate data.
- A user with View permission may read all budget data.
- A user with no share record (resolved or pending) may not access the budget.
- The owner may not be removed from their own budget.
- Pending shares are not counted for access until resolved.

---

## API Surface

Base path: `/api`

### Budgets
| Method | Path | Description |
|--------|------|-------------|
| GET | `/api/budgets` | List budgets accessible to the current user |
| POST | `/api/budgets` | Create a new budget |
| GET | `/api/budgets/{id}` | Get budget metadata |
| PUT | `/api/budgets/{id}` | Rename budget |
| DELETE | `/api/budgets/{id}` | Delete budget (owner only) |

### Sharing
| Method | Path | Description |
|--------|------|-------------|
| GET | `/api/budgets/{id}/shares` | List shares for a budget |
| POST | `/api/budgets/{id}/shares` | Add a share |
| PUT | `/api/budgets/{id}/shares/{shareId}` | Update permission |
| DELETE | `/api/budgets/{id}/shares/{shareId}` | Revoke share |

### Income
| Method | Path | Description |
|--------|------|-------------|
| GET | `/api/budgets/{id}/incomes` | List all incomes (with computed monthly/annually) |
| POST | `/api/budgets/{id}/incomes` | Add income |
| PUT | `/api/budgets/{id}/incomes/{incomeId}` | Update income |
| DELETE | `/api/budgets/{id}/incomes/{incomeId}` | Delete income |
| PUT | `/api/budgets/{id}/incomes/order` | Reorder incomes |

### Outgo
| Method | Path | Description |
|--------|------|-------------|
| GET | `/api/budgets/{id}/outgos` | List all outgos (with computed fields) |
| POST | `/api/budgets/{id}/outgos` | Add outgo |
| PUT | `/api/budgets/{id}/outgos/{outgoId}` | Update outgo |
| DELETE | `/api/budgets/{id}/outgos/{outgoId}` | Delete outgo |
| PUT | `/api/budgets/{id}/outgos/order` | Reorder outgos |
| GET | `/api/budgets/{id}/outgos/categories` | Distinct category values (autocomplete) |
| GET | `/api/budgets/{id}/outgos/payment-sources` | Distinct payment source values (autocomplete) |

### Summary
| Method | Path | Description |
|--------|------|-------------|
| GET | `/api/budgets/{id}/summary` | Full summary (income total, type breakdowns, pre-tax calc) |

### Summary Response Shape
```json
{
  "monthlyIncome": 0.00,
  "annualIncome": 0.00,
  "breakdown": [
    {
      "type": "Need",
      "targetPercent": 50,
      "total": 0.00,
      "annually": 0.00,
      "percent": 0.00,
      "maxAmount": 0.00,
      "remaining": 0.00
    },
    { "type": "Want", "targetPercent": 30, ... },
    { "type": "Save", "targetPercent": 20, ... },
    { "type": "Unspent", "targetPercent": null, "total": 0.00, "annually": 0.00, "percent": 0.00 }
  ],
  "preTaxIncome": {
    "effectiveTaxRate": 0.25,
    "minimumAnnualGross": 0.00,
    "minimumMonthlyGross": 0.00
  }
}
```

---

## Pre-Tax Income Calculator

The calculator takes a configurable effective tax rate (stored per-budget, defaulting to 25%) and computes:

```
minimumAnnualGross = annualOutgoTotal / (1 - effectiveTaxRate)
```

The effective tax rate is stored on the Budget entity and editable from the Summary page via a settings panel.

---

## Frontend Pages & Components

### Routing

```
/                        → redirect to /budgets
/budgets                 → budget list / selector
/budgets/:id/income      → Income page
/budgets/:id/outgo       → Outgo page
/budgets/:id/summary     → Summary page
/budgets/:id/settings    → Budget settings (sharing, tax rate)
```

### Income Page

Editable table with columns: Name, Frequency, Amount, Monthly, Annually.

- Inline editing (click a cell to edit)
- Add row button at bottom
- Delete row button per row
- Drag-to-reorder rows
- Monthly and Annually columns are read-only computed displays

### Outgo Page

Editable table with columns: Name, Category, Type, Frequency, Amount, Monthly, Annually, Payment Source, Monthly%, Notes.

- Same inline editing / add / delete / reorder as Income
- **Category**: free-text input with dropdown suggestions sourced from `/outgos/categories`
- **Payment Source**: same autocomplete pattern via `/outgos/payment-sources`
- **Type**: dropdown (Need / Want / Save)
- **Monthly%**: read-only computed
- Monthly and Annually: read-only computed

### Summary Page

- Header card: Monthly Income, Annual Income
- Table of types (Need, Want, Save, Unspent) with columns: Type, Monthly Total, Annual Total, % of Income, Target %, Max Amount, Remaining
  - Target % shown as a tooltip/info icon rather than a data column to reduce visual noise
  - Unspent row only shows Total, Annually, %
- Pre-Tax Income section: shows minimum annual gross with an editable tax rate field

### Budget Settings Page

- Rename budget
- Effective tax rate input
- Shares table: list current shares, add by user email/ID, change permission, revoke

### Shared Components

- `FrequencySelect` — dropdown for the 9 frequency options
- `MoneyDisplay` — formatted currency display
- `AutocompleteInput` — reusable input with suggestions dropdown
- `BudgetNav` — tabs: Income | Outgo | Summary | Settings
- Auth guard wrapping all budget routes

---

## Authentication

Auth is handled by the external OIDC provider at `auth.stwaddle.com`.

### Backend

- Add `Microsoft.AspNetCore.Authentication.JwtBearer`
- Configure authority and audience from environment variables:
  ```
  AUTH__AUTHORITY=https://auth.stwaddle.com
  AUTH__AUDIENCE=budget-api
  ```
- All `/api` endpoints require `[Authorize]`
- Extract `sub` claim as the user identity key

### Frontend

- Use `oidc-client-ts` (or `@axa-fr/react-oidc`) for the OIDC flow
- Store the access token and attach it as `Authorization: Bearer <token>` on all API calls
- Auth config sourced from env vars baked in at build time:
  ```
  VITE_AUTH_AUTHORITY=https://auth.stwaddle.com
  VITE_AUTH_CLIENT_ID=budget-client
  VITE_AUTH_REDIRECT_URI=https://budget.stwaddle.com/callback
  ```

Auth integration is scaffolded in Phase 2 but login/callback pages are left as stubs; full OIDC flow requires a client registration on `auth.stwaddle.com` (done via the Auth admin UI — create a Public client with Authorization Code + PKCE, add the budget app's redirect URI, and assign the `email`, `profile`, and `roles` scopes).

### User Identity Cache & Pending Share Resolution

On every authenticated request, the Budget API upserts a `KnownUser` record using the `sub`, `email`, and `name` claims from the token. After upserting, it resolves any pending shares by matching `SharedWithEmail` to the user's email claim, setting `SharedWithUserId` and clearing `IsPending`.

---

## Configuration & Environment

`.env.example`:
```
# Database
POSTGRES_HOST=db
POSTGRES_PORT=5432
POSTGRES_DB=budget
POSTGRES_USER=budget
POSTGRES_PASSWORD=changeme

# Auth
AUTH__AUTHORITY=https://auth.stwaddle.com
AUTH__AUDIENCE=budget-api

# Client (baked into Vite build)
VITE_AUTH_AUTHORITY=https://auth.stwaddle.com
VITE_AUTH_CLIENT_ID=budget-client
VITE_AUTH_REDIRECT_URI=https://budget.stwaddle.com/callback
```

`docker-compose.yml` (user-maintained, referenced here for context):
```yaml
services:
  app:
    build: .
    ports:
      - "8080:8080"
    env_file: .env
    depends_on:
      - db
  db:
    image: postgres:16
    environment:
      POSTGRES_DB: ${POSTGRES_DB}
      POSTGRES_USER: ${POSTGRES_USER}
      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}
    volumes:
      - pgdata:/var/lib/postgresql/data
volumes:
  pgdata:
```

---

## Dockerfile (Multi-Stage)

```dockerfile
# Stage 1: Build React client
FROM node:22-alpine AS client-build
WORKDIR /app/client
COPY src/Budget.Client/package*.json ./
RUN npm ci
COPY src/Budget.Client/ ./
RUN npm run build

# Stage 2: Build and publish ASP.NET app
FROM mcr.microsoft.com/dotnet/sdk:9.0 AS api-build
WORKDIR /app
COPY Budget.sln ./
COPY src/Budget.Api/ ./src/Budget.Api/
RUN dotnet publish src/Budget.Api/Budget.Api.csproj -c Release -o /publish

# Stage 3: Runtime image
FROM mcr.microsoft.com/dotnet/aspnet:9.0
WORKDIR /app
COPY --from=api-build /publish ./
COPY --from=client-build /app/client/dist ./wwwroot
EXPOSE 8080
ENTRYPOINT ["dotnet", "Budget.Api.dll"]
```

---

## Implementation Phases

### Phase 1 — Project Scaffolding & Infrastructure
- [ ] Create `src/Budget.Api` ASP.NET Core Web API project (targeting .NET 9)
- [ ] Create `src/Budget.Client` Vite + React + TypeScript project
- [ ] Add both to `Budget.sln`
- [ ] Configure ASP.NET to serve static files from `wwwroot` with SPA fallback
- [ ] Configure Vite dev proxy to forward `/api` requests to the ASP.NET dev port
- [ ] Add EF Core + Npgsql packages; scaffold `AppDbContext`
- [ ] Define all entity models and configure EF mappings
- [ ] Add initial migration
- [ ] Write `Dockerfile` (multi-stage as above)
- [ ] Write `.env.example`
- [ ] Verify clean build: `dotnet build` + `npm run build`

### Phase 2 — Authentication Scaffolding
- [ ] Add JWT bearer auth to ASP.NET; read authority/audience from config
- [ ] Add `[Authorize]` to a test endpoint and verify token validation works
- [ ] Add middleware to upsert `KnownUser` and resolve pending shares on each authenticated request
- [ ] Add `oidc-client-ts` to the React app
- [ ] Create auth context / provider with login, logout, and token storage
- [ ] Add stub `/callback` route for OIDC redirect
- [ ] Protect all budget routes with an auth guard
- [ ] Verify clean build

### Phase 3 — Budget & Sharing API
- [ ] `BudgetsController`: CRUD + list
- [ ] Authorization service: checks owner vs. share permissions
- [ ] `SharesController`: list / add / update / delete
- [ ] Apply authorization service to all budget-scoped controllers
- [ ] Integration-test the happy paths manually
- [ ] Verify clean build

### Phase 4 — Income API & Page
- [ ] `IncomesController`: list, add, update, delete, reorder
- [ ] Frequency calculation service (shared utility used by all computed fields)
- [ ] Income list DTO including computed Monthly and Annually
- [ ] React Income page: table, inline edit, add/delete row, drag reorder
- [ ] `FrequencySelect` and `MoneyDisplay` shared components
- [ ] Verify clean build

### Phase 5 — Outgo API & Page
- [ ] `OutgosController`: list, add, update, delete, reorder, categories, payment-sources
- [ ] Outgo list DTO including Monthly, Annually, MonthlyPercentage
- [ ] React Outgo page: table with all columns, inline edit, add/delete, reorder
- [ ] `AutocompleteInput` component wired to categories and payment-sources endpoints
- [ ] Verify clean build

### Phase 6 — Summary API & Page
- [ ] `SummaryController`: compute and return full summary shape
- [ ] Pre-tax income calculation; `EffectiveTaxRate` field on Budget entity + migration
- [ ] React Summary page: income header cards, type breakdown table, pre-tax section
- [ ] Editable tax rate on Summary page (PATCH to budget settings)
- [ ] Verify clean build

### Phase 7 — Budget Settings & Sharing UI
- [ ] Budget list / selector page (landing page after login)
- [ ] Budget Settings page: rename, tax rate, shares table
- [ ] Share add flow: input email address, choose permission, submit; show "pending" badge for users not yet seen
- [ ] `BudgetNav` tab component used across all budget pages
- [ ] Verify clean build

### Phase 8 — Polish & Production Readiness
- [ ] Global error boundary and API error toasts in React
- [ ] Loading skeletons for tables
- [ ] Confirm-on-delete dialogs
- [ ] EF Core migration applied automatically on startup (`context.Database.MigrateAsync()`)
- [ ] Health check endpoint (`/healthz`)
- [ ] Final Dockerfile review and end-to-end smoke test inside Docker
- [ ] Verify clean build

---

## Open Questions / Deferred Decisions

- **Optimistic vs. server-side updates**: The React tables can either update locally then sync, or round-trip to the server. Phase 4–5 will use server-round-trip for simplicity; can add optimistic updates in Phase 8 if the UX feels slow.
- **Row reordering persistence**: Drag-to-reorder uses a `SortOrder` integer column. The reorder endpoint accepts an ordered list of IDs and bulk-updates SortOrder. This is straightforward but may need debouncing if the user drags frequently.
- **Auth client registration**: Before Phase 2 can be fully tested end-to-end, a client must be registered in the Auth admin UI for the Budget app. Required fields: client type = Public, grant = Authorization Code + PKCE, redirect URI = `http://localhost:5173/callback` (dev) + production URL, scopes = `email profile roles`.