# CLAUDE.md

Guidance for Claude Code when working in this repository.

## Project Overview

Personal finance tracker. Bank statements are ingested via an N8N workflow (in the smarthome repo at `docker/automation/workflows/cc-statement-processor-paperless.json`) that sends PDFs to Gemini 2.5 Flash for extraction, then inserts into PostgreSQL.

- **App**: Next.js 16 App Router, TypeScript, Tailwind CSS
- **DB**: PostgreSQL container `postgres-personal`, database `personal`, user `personal`
- **Auth**: `X-Forwarded-User` header (email) set by Traefik → `participants.email`. In dev/fallback: participant id=1 ("Me")
- **Runs at**: port 3000 inside container, exposed on host port 4100, proxied at `https://finance.bosecamp.com`

## Common Commands

```bash
# Build and deploy (from smarthome repo root)
docker compose --env-file docker/common.env --env-file docker/finance/.env \
  -f docker/finance/docker-compose.yml up -d --build

# IMPORTANT: docker restart does NOT pick up a new image — always use the compose command above

# DB access
docker exec postgres-personal psql -U personal -d personal

# View logs
docker logs finance -f
```

## Architecture

### Key Files

| File | Purpose |
|------|---------|
| `src/lib/db.ts` | `queryRaw<T>()` — the only DB query function; uses `pg` directly |
| `src/lib/queries.ts` | All SQL query functions (no ORM); import `queryRaw` from `@/lib/db` |
| `src/lib/hooks.ts` | TanStack Query hooks for all API calls |
| `src/lib/auth.ts` | `getCurrentUser()` — reads `X-Forwarded-User` header |
| `src/lib/categories.ts` | Canonical category list (`CATEGORIES` array + `formatCategory()`) |
| `src/app/api/*/route.ts` | API route handlers |
| `src/components/` | Shared UI components |

### Data Flow

- All queries in `src/lib/queries.ts` use raw SQL via `queryRaw` from `src/lib/db.ts`
- API routes call query functions and return `NextResponse.json()`
- Frontend uses hooks from `src/lib/hooks.ts` (TanStack Query) — never fetches directly
- Auth is always checked first in every API route: `const user = await getCurrentUser(req)`

### Owner Scoping

All data is scoped by `owner_id`. The effective owner of a transaction is:
```sql
COALESCE(t.owner_id, s.owner_id)
```
- Statement-linked transactions: owner comes from `statements.owner_id`
- Manual transactions: `statement_id IS NULL`, owner stored directly in `transactions.owner_id`

The effective merchant and category always prefer overrides:
```sql
COALESCE(o.merchant_normalized, t.merchant_normalized, t.merchant_name)  -- merchant
COALESCE(o.category_override, t.category)                                 -- category
```

## Database

```bash
# Schema inspection
docker exec postgres-personal psql -U personal -d personal -c "\d transactions"

# Apply a migration SQL file
docker exec postgres-personal psql -U personal -d personal < prisma/migrations/<name>/migration.sql
```

### Key Tables

- `statements` — one row per billing period per bank account
- `transactions` — line items; `statement_id` is nullable (NULL = manual entry)
- `transaction_overrides` — user corrections to AI-extracted data (category, merchant, notes)
- `transaction_splits` — shared expense tracking (participant, share_percent, settled)
- `transaction_tags` — many-to-many join to `tags`
- `rules` — auto-categorisation rules (JSONB conditions + actions)
- `participants` — people; `id=1` is "Me" (the primary user)
- `account_owner_mappings` — persists bank+account → owner assignments

### Rules System

Conditions are AND-evaluated. Fields: `merchant_normalized`, `description`, `category`, `bank_name`, `amount`, `transaction_type`. Operators: `contains`, `equals`, `starts_with`, `gt`, `lt`, `not_equals`. Actions: `set_category`, `set_merchant`, `add_tag_ids`, `apply_split`.

`contains` and `equals` operators are case-insensitive (both sides `.toLowerCase()`).

## Development Patterns

### Adding a new API route

1. Create `src/app/api/<resource>/route.ts`
2. Always call `getCurrentUser(req)` first; return 403 if null
3. Write SQL in `src/lib/queries.ts` using `queryRaw`
4. Add a TanStack Query hook in `src/lib/hooks.ts`

### Adding a new condition field to rules

Two files only:
- `src/app/api/rules/apply/route.ts` — add to `Condition.field` union, `TxFields` interface, and `evaluateCondition()` switch
- `src/app/rules/page.tsx` — add to `FIELDS` array; add special rendering if needed (e.g. enum dropdown for `transaction_type`)

### Modifying queries

- All JOINs to `statements` must be `LEFT JOIN` (manual transactions have no statement)
- Owner filter pattern: `WHERE COALESCE(t.owner_id, s.owner_id) = $1`
- Bank name pattern: `COALESCE(s.bank_name, 'Manual') as bank_name`

## Known Gaps / TODOs

See `README.md` → **Known Gaps / TODOs** for full details.

**Payment provider tracking**: `merchant_normalized` currently conflates payment provider (PayPal, Afterpay, Zip) with the actual merchant. Plan: add `payment_provider` column, update Gemini prompt to extract it separately, backfill from `merchant_name` patterns, surface in UI filters.