Invoice Lifecycle

Use this skill for invoice-domain work in this repository.

Key context

• The app is an invoice product with Bulgarian-market requirements.
• Invoice data is primarily stored through Supabase tables that mirror the Prisma schema.
• Invoice creation logic and list handling live in src/app/api/invoices/route.ts.
• Invoices are intended to be immutable after issuance. Cancellation should be modeled through follow-up documents such as credit notes, not silent mutation of historical records.

Instructions

1. Read the relevant invoice route, form page, and schema before editing business logic.
2. Resolve the current user through getServerSession(authOptions) and resolveSessionUser(session.user) instead of trusting raw session fields alone.
3. Scope every invoice query and mutation to the current user.
4. Recompute subtotal, taxAmount, and total from the submitted line items on the server. Do not trust client-calculated totals.
5. Preserve invoice numbering and sequence behavior. Treat numbering changes as high risk.