# CLAUDE.md

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

## Commands

```bash
# Development
pnpm dev                    # Next.js + Turbopack at localhost:3000
pnpm lint                   # ESLint
pnpm type-check             # tsc --noEmit

# Tests
pnpm test                   # Unit tests (Vitest, jsdom)
pnpm test:watch             # Unit tests in watch mode
pnpm test:integration       # Integration tests (Vitest, node + real DB)
pnpm test:e2e               # E2E tests (Playwright, headless)
pnpm test:e2e:ui            # E2E tests with interactive UI
pnpm test:all               # All test suites

# Run a single test file
pnpm test -- tests/unit/po-line-items-editor.test.tsx
pnpm test:integration -- tests/integration/create-po.test.ts

# Database
pnpm db:migrate             # Create + apply migration (dev)
pnpm db:migrate:deploy      # Apply migrations (CI/prod)
pnpm db:seed                # Populate sample data
pnpm db:studio              # Prisma GUI at localhost:5555
pnpm db:reset               # Drop + recreate + seed (dev)
```

## Architecture

### Overview

Internal purchase order management system for a maritime company. Full-stack Next.js 15 App Router app with Prisma + PostgreSQL, NextAuth v5 credentials auth, and Tailwind CSS v4.

**Key design decisions:**
- Server Components for all data-fetching pages; Client Components only where interactivity is needed
- Server Actions for all mutations (form submissions, approvals, etc.)
- Prisma `Decimal` fields **cannot** be passed directly to Client Components — convert with `Number()` in the Server Component before passing as props (see `po-detail.tsx` → `lineItemsForEditor` pattern)
- File storage toggles automatically: Cloudflare R2 in production, `.dev-uploads/` directory in development
- Email toggles automatically: Resend in production, console log in development

### PO Lifecycle (State Machine)

`lib/po-state-machine.ts` enforces all status transitions. The canonical flow:

```
DRAFT → SUBMITTED → MGR_REVIEW → MGR_APPROVED → SENT_FOR_PAYMENT → PAID_DELIVERED → CLOSED
                        ↓↑
               EDITS_REQUESTED / REJECTED / VENDOR_ID_PENDING
```

Every status change is validated against the state machine and recorded as a `POAction` row (audit trail).

### Role-Based Permissions

`lib/permissions.ts` defines `hasPermission(role, permission)` and `requirePermission(role, permission)`. Roles: `TECHNICAL`, `MANNING`, `ACCOUNTS`, `MANAGER`, `SUPERUSER`, `AUDITOR`, `ADMIN`.

**Pattern:** Server Actions call `requirePermission()` at the top before any DB write.

### Key Directories

- `app/(portal)/` — All authenticated pages (portal layout with sidebar)
- `app/api/po/[id]/export/` — PDF and XLSX export endpoint
- `lib/validations/po.ts` — Zod schemas for PO forms; exports `TC_FIXED_LINE` and `TC_DEFAULTS`
- `lib/po-state-machine.ts` — All valid status transitions with required roles
- `lib/notifier.ts` — Email dispatch (Resend in prod, console in dev)
- `lib/storage.ts` — File upload/download (R2 in prod, local in dev)
- `components/po/` — PO-specific components (line items editor, status badge, etc.)
- `tests/integration/helpers.ts` — `makeSession()`, `makePoForm()`, `fd()` for integration test setup

### Cost Centre Model

A PO's "cost centre" is either a **Vessel** or a **Site**. `PurchaseOrder` has both `vesselId String?` (nullable) and `siteId String?` — exactly one is set.

**Form encoding:** All PO creation/edit forms use a `costCentreRef` field with values `v:<vesselId>` (vessel) or `s:<siteId>` (site). Server actions parse this to set the correct FK.

**Display pattern:** `po.vessel?.name ?? po.site?.name ?? "—"` everywhere a cost centre name is shown.

**URL pre-select:** `/po/new?costCentreRef=v:<id>` or `?costCentreRef=s:<id>`.

**Terminology:** Admin pages use the real entity names (Vessel Management, Sites). PO-facing pages use "Cost Centre" for the combined concept. Budget heads are labelled "Accounting Code" (not "Account").

### GST Calculation

`totalAmount = sum(quantity × unitPrice × (1 + gstRate))` for each line item. The `gstRate` is stored as a decimal on `POLineItem` (e.g., `0.18` = 18%). This applies in Server Actions when computing `totalPrice` per line and the PO `totalAmount`.

### Environment Variables

```
NEXTAUTH_SECRET         # Required always
NEXTAUTH_URL            # Required always (e.g., http://localhost:3000)
DATABASE_URL            # PostgreSQL connection string

# Optional in dev (defaults to local storage + console email):
R2_ACCOUNT_ID, R2_ACCESS_KEY_ID, R2_SECRET_ACCESS_KEY, R2_BUCKET_NAME, R2_PUBLIC_URL
RESEND_API_KEY, EMAIL_FROM, EMAIL_FROM_NAME
```
