finance-app/CLAUDE.md

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

# 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:

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:

COALESCE(o.merchant_normalized, t.merchant_normalized, t.merchant_name)  -- merchant
COALESCE(o.category_override, t.category)                                 -- category

Database

# 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.