feat(customers): let users set a customer number shown on the invoice (#957)

Implements #914 (kundnummer on customers, printed on the invoice PDF).

- Migration: nullable text column customers.customer_number, no unique
  constraint in v1 so existing rows and imports keep working.
- API: CreateCustomerSchema/UpdateCustomerSchema accept an optional
  customer_number (trimmed, max 32 chars, nullable-then-optional so the
  OpenAPI registry sees it as not required); create/update routes
  persist it and normalize empty string to null so it can be cleared.
- v1 public API: customers create/detail/update round-trip the field
  (insert and update field lists, response projections, response
  schemas), and the invoices :send route fetches customer_number in its
  explicit customer join so the emailed PDF matches the downloaded one
  (the pdf route already selects customers(*)).
- UI: optional Kundnummer field in CustomerForm (next-intl keys in both
  sv and en), wired into the edit dialog's initialData; read-only
  Kundnummer row on the customer detail page's business-details card.
- Invoice PDF: renders "Kundnr:" / "Customer no.:" in the customer box
  when set; the PDF reads the live customers join, so no snapshot
  column is needed.
- Tests: route tests cover 400 validation, trimming, clearing with
  null/empty, and omit-leaves-untouched on POST and PATCH; v1 tests
  cover the create/update round-trip (insert/update payload + response
  projection) and the :send customer-join projection.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

app/api/customers/[id]/route.ts

@@ -58,6 +58,8 @@ export const PATCH = withRouteContext(
     const updateData: Record<string, unknown> = {}
     if (body.name !== undefined) updateData.name = body.name
     if (body.customer_type !== undefined) updateData.customer_type = body.customer_type
+    // Empty string clears the customer number, same as an explicit null.
+    if (body.customer_number !== undefined) updateData.customer_number = body.customer_number || null
     if (body.email !== undefined) updateData.email = body.email
     if (body.phone !== undefined) updateData.phone = body.phone
     if (body.address_line1 !== undefined) updateData.address_line1 = body.address_line1

app/api/customers/__tests__/customer-number.test.ts

@@ -0,0 +1,230 @@
+/**
+ * Tests for the customer_number field (kundnummer, issue #914) on
+ * POST /api/customers and PATCH /api/customers/[id].
+ *
+ * Exercises the routes through the real withRouteContext wrapper, mocking its
+ * auth/company/write dependencies. Uses a hand-rolled Supabase mock that
+ * records insert/update payloads so the tests can assert the route-level
+ * normalization: the value is trimmed by the Zod schema, and empty string or
+ * null clears the column to null.
+ */
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { createMockRequest, parseJsonResponse } from '@/tests/helpers'
+import { eventBus } from '@/lib/events'
+
+const captured: { insert: unknown[]; update: unknown[] } = { insert: [], update: [] }
+let queryResult: { data: unknown; error: unknown } = { data: null, error: null }
+
+const buildChain = (): unknown =>
+  new Proxy(
+    {},
+    {
+      get(_target, prop) {
+        if (prop === 'then') {
+          return (resolve: (v: unknown) => void) => resolve(queryResult)
+        }
+        return (...args: unknown[]) => {
+          if (prop === 'insert') captured.insert.push(args[0])
+          if (prop === 'update') captured.update.push(args[0])
+          return buildChain()
+        }
+      },
+    },
+  )
+
+const supabase = {
+  from: vi.fn(() => buildChain()),
+  rpc: vi.fn(() => buildChain()),
+}
+
+const requireAuthMock = vi.fn()
+vi.mock('@/lib/auth/require-auth', () => ({
+  requireAuth: (...args: unknown[]) => requireAuthMock(...args),
+}))
+
+vi.mock('@/lib/company/context', () => ({
+  getActiveCompanyId: vi.fn().mockResolvedValue('company-1'),
+  requireCompanyId: vi.fn().mockResolvedValue('company-1'),
+}))
+
+const requireWriteMock = vi.fn()
+vi.mock('@/lib/auth/require-write', () => ({
+  requireWritePermission: (...args: unknown[]) => requireWriteMock(...args),
+}))
+
+vi.mock('@/lib/init', () => ({ ensureInitialized: vi.fn() }))
+
+import { POST } from '../route'
+import { PATCH } from '../[id]/route'
+
+type CustomerRow = { customer_number?: string | null }
+
+describe('customer_number on POST /api/customers', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    eventBus.clear()
+    captured.insert.length = 0
+    captured.update.length = 0
+    queryResult = { data: null, error: null }
+    requireAuthMock.mockResolvedValue({ user: { id: 'user-1' }, supabase })
+    requireWriteMock.mockResolvedValue({ ok: true })
+  })
+
+  it('rejects a customer_number longer than 32 characters with 400', async () => {
+    const request = createMockRequest('/api/customers', {
+      method: 'POST',
+      body: {
+        name: 'Test AB',
+        customer_type: 'swedish_business',
+        customer_number: 'X'.repeat(33),
+      },
+    })
+
+    const response = await POST(request, { params: Promise.resolve({}) })
+    const { status } = await parseJsonResponse(response)
+
+    expect(status).toBe(400)
+    expect(captured.insert).toHaveLength(0)
+  })
+
+  it('stores a trimmed customer_number on create', async () => {
+    queryResult = {
+      data: { id: 'cust-1', name: 'Test AB', customer_type: 'swedish_business', customer_number: '1001' },
+      error: null,
+    }
+
+    const request = createMockRequest('/api/customers', {
+      method: 'POST',
+      body: {
+        name: 'Test AB',
+        customer_type: 'swedish_business',
+        customer_number: '  1001  ',
+      },
+    })
+
+    const response = await POST(request, { params: Promise.resolve({}) })
+    const { status, body } = await parseJsonResponse<{ data: CustomerRow }>(response)
+
+    expect(status).toBe(200)
+    expect((captured.insert[0] as CustomerRow).customer_number).toBe('1001')
+    expect(body.data.customer_number).toBe('1001')
+  })
+
+  it('normalizes an empty customer_number to null on create', async () => {
+    queryResult = {
+      data: { id: 'cust-1', name: 'Test AB', customer_type: 'swedish_business', customer_number: null },
+      error: null,
+    }
+
+    const request = createMockRequest('/api/customers', {
+      method: 'POST',
+      body: { name: 'Test AB', customer_type: 'swedish_business', customer_number: '' },
+    })
+
+    const response = await POST(request, { params: Promise.resolve({}) })
+    const { status } = await parseJsonResponse(response)
+
+    expect(status).toBe(200)
+    expect((captured.insert[0] as CustomerRow).customer_number).toBeNull()
+  })
+
+  it('defaults customer_number to null when omitted', async () => {
+    queryResult = {
+      data: { id: 'cust-1', name: 'Test AB', customer_type: 'swedish_business', customer_number: null },
+      error: null,
+    }
+
+    const request = createMockRequest('/api/customers', {
+      method: 'POST',
+      body: { name: 'Test AB', customer_type: 'swedish_business' },
+    })
+
+    const response = await POST(request, { params: Promise.resolve({}) })
+    const { status } = await parseJsonResponse(response)
+
+    expect(status).toBe(200)
+    expect((captured.insert[0] as CustomerRow).customer_number).toBeNull()
+  })
+})
+
+describe('customer_number on PATCH /api/customers/[id]', () => {
+  const routeParams = { params: Promise.resolve({ id: 'cust-1' }) }
+
+  beforeEach(() => {
+    vi.clearAllMocks()
+    eventBus.clear()
+    captured.insert.length = 0
+    captured.update.length = 0
+    queryResult = {
+      data: { id: 'cust-1', customer_type: 'swedish_business' },
+      error: null,
+    }
+    requireAuthMock.mockResolvedValue({ user: { id: 'user-1' }, supabase })
+    requireWriteMock.mockResolvedValue({ ok: true })
+  })
+
+  it('rejects a customer_number longer than 32 characters with 400', async () => {
+    const request = createMockRequest('/api/customers/cust-1', {
+      method: 'PATCH',
+      body: { customer_number: 'X'.repeat(33) },
+    })
+
+    const response = await PATCH(request, routeParams)
+    const { status } = await parseJsonResponse(response)
+
+    expect(status).toBe(400)
+    expect(captured.update).toHaveLength(0)
+  })
+
+  it('updates the customer_number', async () => {
+    const request = createMockRequest('/api/customers/cust-1', {
+      method: 'PATCH',
+      body: { customer_number: 'K-42' },
+    })
+
+    const response = await PATCH(request, routeParams)
+    const { status } = await parseJsonResponse(response)
+
+    expect(status).toBe(200)
+    expect((captured.update[0] as CustomerRow).customer_number).toBe('K-42')
+  })
+
+  it('clears the customer_number when null is sent', async () => {
+    const request = createMockRequest('/api/customers/cust-1', {
+      method: 'PATCH',
+      body: { customer_number: null },
+    })
+
+    const response = await PATCH(request, routeParams)
+    const { status } = await parseJsonResponse(response)
+
+    expect(status).toBe(200)
+    expect((captured.update[0] as CustomerRow).customer_number).toBeNull()
+  })
+
+  it('clears the customer_number when an empty string is sent', async () => {
+    const request = createMockRequest('/api/customers/cust-1', {
+      method: 'PATCH',
+      body: { customer_number: '' },
+    })
+
+    const response = await PATCH(request, routeParams)
+    const { status } = await parseJsonResponse(response)
+
+    expect(status).toBe(200)
+    expect((captured.update[0] as CustomerRow).customer_number).toBeNull()
+  })
+
+  it('leaves the customer_number untouched when the field is omitted', async () => {
+    const request = createMockRequest('/api/customers/cust-1', {
+      method: 'PATCH',
+      body: { name: 'New Name AB' },
+    })
+
+    const response = await PATCH(request, routeParams)
+    const { status } = await parseJsonResponse(response)
+
+    expect(status).toBe(200)
+    expect(captured.update[0]).not.toHaveProperty('customer_number')
+  })
+})

app/api/customers/route.ts

@@ -49,6 +49,7 @@ export const POST = withRouteContext(
         company_id: companyId,
         name: body.name,
         customer_type: body.customer_type,
+        customer_number: body.customer_number || null,
         email: body.email,
         phone: body.phone,
         address_line1: body.address_line1,