Assist_Design/CLAUDE.md

# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Project Overview

Customer portal with BFF (Backend for Frontend) architecture. Users can self-register, manage subscriptions, view/pay invoices, and manage support cases.

**Systems of Record:**

- **WHMCS**: Billing, subscriptions, invoices, authoritative address storage
- **Salesforce**: CRM (Accounts, Contacts, Cases), order address snapshots
- **Portal**: Next.js UI + NestJS BFF

## Development Commands

```bash
# Start development environment (PostgreSQL + Redis via Docker)
pnpm dev:start

# Start both frontend and backend with hot reload
pnpm dev

# Build domain package (required before running apps if domain changed)
pnpm domain:build

# Type checking
pnpm type-check

# Linting
pnpm lint
pnpm lint:fix

# Database commands
pnpm db:migrate     # Run migrations
pnpm db:studio      # Open Prisma Studio GUI
pnpm db:generate    # Generate Prisma client

# Run tests
pnpm test           # All packages
pnpm --filter @customer-portal/bff test   # BFF only

# Stop services
pnpm dev:stop
```

**Access points:**

- Frontend: http://localhost:3000
- Backend API: http://localhost:4000/api
- Prisma Studio: http://localhost:5555

## Architecture

### Monorepo Structure

```
apps/
├── portal/          # Next.js 15 frontend (React 19, Tailwind, shadcn/ui)
└── bff/             # NestJS 11 backend (Prisma, BullMQ, Zod validation)

packages/
└── domain/          # Unified domain layer (contracts, schemas, provider mappers)
```

### Three-Layer Boundary (Non-Negotiable)

| Layer  | Location           | Purpose                                                                        |
| ------ | ------------------ | ------------------------------------------------------------------------------ |
| Domain | `packages/domain/` | Shared contracts, Zod validation, provider mappers. Framework-agnostic.        |
| BFF    | `apps/bff/`        | HTTP boundary, orchestration, external integrations (Salesforce/WHMCS/Freebit) |
| Portal | `apps/portal/`     | UI layer. Pages are thin wrappers over feature modules.                        |

### Domain Package Structure

Each domain module follows this pattern:

```
packages/domain/<module>/
├── contract.ts       # Normalized types (provider-agnostic)
├── schema.ts         # Zod validation schemas
├── index.ts          # Public exports
└── providers/        # Provider-specific adapters (BFF-only)
    └── whmcs/
        ├── raw.types.ts   # Raw API response types
        └── mapper.ts      # Transform raw → domain
```

### Import Rules (ESLint Enforced)

**Allowed (Portal + BFF):**

```typescript
import type { Invoice } from "@customer-portal/domain/billing";
import { invoiceSchema } from "@customer-portal/domain/billing";
import { Formatting } from "@customer-portal/domain/toolkit";
```

**Allowed (BFF only):**

```typescript
import { Whmcs } from "@customer-portal/domain/billing/providers";
```

**Forbidden everywhere:**

```typescript
// Root import
import { Billing } from "@customer-portal/domain";
// Deep imports beyond entrypoints
import { Invoice } from "@customer-portal/domain/billing/contract";
import { transformWhmcsInvoice } from "@customer-portal/domain/billing/providers/whmcs/mapper";
```

**Forbidden in Portal:**

```typescript
// Portal must NEVER import provider adapters
import { Whmcs } from "@customer-portal/domain/billing/providers";
```

### Portal Feature Architecture

```
apps/portal/src/
├── app/              # Next.js App Router (thin route shells, no API calls)
├── components/       # Atomic design: atoms/, molecules/, organisms/, templates/
├── core/             # App infrastructure: api/, logger/, providers/
├── features/         # Feature modules with: api/, stores/, components/, hooks/, views/
└── shared/           # Cross-feature: hooks/, utils/, constants/
```

**Feature module pattern:**

- `api/`: Data fetching layer (built on shared apiClient)
- `stores/`: Zustand state management
- `hooks/`: React Query hooks wrapping API services
- `components/`: Feature-specific UI
- `views/`: Page-level view components
- `index.ts`: Feature public API (barrel exports)

### BFF Integration Pattern

**Map Once, Use Everywhere:**

```
External API → Integration Service → Domain Mapper → Domain Type → Use Directly
```

Integration services live in `apps/bff/src/integrations/{provider}/`:

- `services/`: Connection services, entity-specific services
- `utils/`: Query builders (SOQL, etc.)

Domain mappers live in `packages/domain/{module}/providers/{provider}/`:

- Integration services fetch data and call domain mappers
- No business logic in integration layer
- No double transformation

## Key Patterns

### Validation (Zod-First)

- Schemas live in domain: `packages/domain/<module>/schema.ts`
- Derive types from schemas: `export type X = z.infer<typeof xSchema>`
- Query params: use `z.coerce.*` for URL strings

### BFF Controllers

- Controllers are thin: no business logic, no Zod imports
- Use `createZodDto(schema)` with global `ZodValidationPipe`
- Integrations: build queries in utils, fetch data, transform via domain mappers

### Logging

- BFF: Use `nestjs-pino` Logger, inject via constructor
- Portal: Use `@/core/logger`
- No `console.log` in production code (ESLint enforced)

### Naming

- No `any` in public APIs
- No `console.log` (use logger)
- Avoid `V2` suffix in service names

## Documentation

Read before coding:

- `docs/README.md` (entrypoint)
- `docs/development/` (BFF/Portal/Domain patterns)
- `docs/architecture/` (boundaries)
- `docs/integrations/` (external API details)

**Rule: Never guess endpoint behavior or payload shapes. Find docs or existing implementation first.**