fix(bookkeeping): honor underlag VAT via vat_amount override in categorize flow (#717)

* fix(bookkeeping): honor underlag VAT via vat_amount override in categorize flow The categorize flow always derived VAT as rate × gross/(1+rate) from the transaction amount, with no way to use the underlag's actual moms. On e.g. a restaurant receipt with dricks (no VAT on the tip), the agent could see the document's correct VAT but the staged booking recomputed the wrong rate-based amount on every attempt. - buildMappingResultFromCategory: optional vatAmountOverride replaces the rate-derived VAT line ("Ingående/Utgående moms (enligt underlag)"; 0 = no VAT line). Rejects negatives, amounts above the 25%-extraction bound, and combination with reverse_charge / VAT-less treatments / private. - gnubok_categorize_transaction: new vat_amount input, threaded into the staged preview and persisted in the operation params. - commitCategorizeTransaction: reads params.vat_amount so the approved posting matches the staged preview exactly. - PATCH /api/pending-operations/[id]: accepts vat_amount (null clears); preserves a staged override across category edits while the treatment still carries rate-based VAT, drops it when it no longer does. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * review: guard order + agent guidance on vat_amount (PR #717 bots) - Check treatment compatibility before the 25%-extraction bound so an oversized override on reverse_charge reports the actual mistake (the treatment), not the amount. Document why the typeof re-check stays: commit-time params come from jsonb, so TS types don't hold at runtime. - vat_amount property description now warns that foreign VAT is never deductible as ingående moms and that a 0-moms document should use vat_treatment="exempt" rather than vat_amount=0. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * fix(mcp): tools/list payload budget + reject vat_amount 0 core-only failed: the verbose vat_amount descriptions pushed the projected tools/list payload to 36,051 tokens (ceiling 36,000; main is at 35,862). Per the guard's own guidance, trim descriptions instead of bumping: now 35,943. Folds in the Swedish review's round-2 point while trimming: vat_amount 0 is now rejected with a pointer to vat_treatment "exempt". A 0-moms document is an exempt supply — "exempt" produces the identical expense booking and the correct income account (3004), so 0 had no use case and only created a silent momsdeklaration misclassification path. Schema declares exclusiveMinimum: 0. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * fix(bookkeeping): use roundOre for vat_amount math (antipattern ratchet) Second core-only failure: the naive-ore-round ratchet caught the new Math.round(x*100)/100 lines (662 > baseline 661). Switch the override path to roundOre from lib/money — including the pre-existing computed-VAT line this PR touched — and ratchet the baseline down (659, raw-route-auth 168 locked in from main-side fixes). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> --------- Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
2026-06-12 11:42:21 +02:00
parent f548b04aed
commit 8e8b63a200
8 changed files with 412 additions and 22 deletions
@@ -24,8 +24,10 @@ vi.mock('@/lib/auth/require-write', () => ({
 vi.mock('@/lib/init', () => ({ ensureInitialized: vi.fn() }))

 const mappingMock = vi.fn()
+const accountMappingMock = vi.fn()
 vi.mock('@/lib/bookkeeping/category-mapping', () => ({
  buildMappingResultFromCategory: (...args: unknown[]) => mappingMock(...args),
+  getCategoryAccountMapping: (...args: unknown[]) => accountMappingMock(...args),
 }))

 import { PATCH } from '../route'
@@ -43,6 +45,13 @@ beforeEach(() => {
    credit_account: '1930',
    vat_lines: [],
  })
+  accountMappingMock.mockReturnValue({
+    debitAccount: '5410',
+    creditAccount: '1930',
+    vatTreatment: 'standard_25',
+    vatDebitAccount: '2641',
+    vatCreditAccount: null,
+  })
 })

 describe('PATCH /api/pending-operations/[id]', () => {
@@ -202,6 +211,146 @@ describe('PATCH /api/pending-operations/[id]', () => {
    expect(mappingMock).toHaveBeenCalledTimes(1)
  })

+  it('preserves a staged vat_amount override when the new treatment still carries VAT', async () => {
+    enqueue({
+      data: {
+        id: 'op-1',
+        company_id: 'company-1',
+        operation_type: 'categorize_transaction',
+        status: 'pending',
+        params: {
+          transaction_id: 'tx-1',
+          category: 'expense_representation',
+          vat_treatment: 'reduced_12',
+          vat_amount: 42.43,
+        },
+        preview_data: {},
+        title: '',
+      },
+    })
+    enqueue({ data: { id: 'tx-1', company_id: 'company-1', amount: -415.8, currency: 'SEK' } })
+    enqueue({ data: { entity_type: 'enskild_firma' } })
+    enqueue({ data: { id: 'op-1', params: {}, preview_data: {}, title: '', status: 'pending' } })
+
+    const res = await PATCH(
+      createMockRequest('/api/pending-operations/op-1', {
+        method: 'PATCH',
+        body: { category: 'expense_office' },
+      }),
+      createMockRouteParams({ id: 'op-1' }),
+    )
+    expect(res.status).toBe(200)
+    // 6th arg = vat_amount override, carried over from the staged params
+    // (vat_treatment persists too — only the category changed)
+    expect(mappingMock).toHaveBeenCalledWith(
+      'expense_office', expect.anything(), true, 'enskild_firma', 'reduced_12', 42.43,
+    )
+  })
+
+  it('drops a stale vat_amount override when the new treatment is VAT-less', async () => {
+    accountMappingMock.mockReturnValueOnce({
+      debitAccount: '6570',
+      creditAccount: '1930',
+      vatTreatment: null,
+      vatDebitAccount: null,
+      vatCreditAccount: null,
+    })
+    enqueue({
+      data: {
+        id: 'op-1',
+        company_id: 'company-1',
+        operation_type: 'categorize_transaction',
+        status: 'pending',
+        params: {
+          transaction_id: 'tx-1',
+          category: 'expense_representation',
+          vat_treatment: 'reduced_12',
+          vat_amount: 42.43,
+        },
+        preview_data: {},
+        title: '',
+      },
+    })
+    enqueue({ data: { id: 'tx-1', company_id: 'company-1', amount: -415.8, currency: 'SEK' } })
+    enqueue({ data: { entity_type: 'enskild_firma' } })
+    enqueue({ data: { id: 'op-1', params: {}, preview_data: {}, title: '', status: 'pending' } })
+
+    const res = await PATCH(
+      createMockRequest('/api/pending-operations/op-1', {
+        method: 'PATCH',
+        body: { category: 'expense_bank_fees', vat_treatment: null },
+      }),
+      createMockRouteParams({ id: 'op-1' }),
+    )
+    expect(res.status).toBe(200)
+    expect(mappingMock).toHaveBeenCalledWith(
+      'expense_bank_fees', expect.anything(), true, 'enskild_firma', undefined, null,
+    )
+  })
+
+  it('returns 400 when vat_amount is explicitly set on a VAT-less treatment', async () => {
+    accountMappingMock.mockReturnValueOnce({
+      debitAccount: '5410',
+      creditAccount: '1930',
+      vatTreatment: null,
+      vatDebitAccount: null,
+      vatCreditAccount: null,
+    })
+    enqueue({
+      data: {
+        id: 'op-1',
+        company_id: 'company-1',
+        operation_type: 'categorize_transaction',
+        status: 'pending',
+        params: { transaction_id: 'tx-1', category: 'expense_other' },
+        preview_data: {},
+        title: '',
+      },
+    })
+    enqueue({ data: { id: 'tx-1', company_id: 'company-1', amount: -500, currency: 'SEK' } })
+    enqueue({ data: { entity_type: 'enskild_firma' } })
+
+    const res = await PATCH(
+      createMockRequest('/api/pending-operations/op-1', {
+        method: 'PATCH',
+        body: { vat_treatment: 'exempt', vat_amount: 50 },
+      }),
+      createMockRouteParams({ id: 'op-1' }),
+    )
+    expect(res.status).toBe(400)
+    expect(mappingMock).not.toHaveBeenCalled()
+  })
+
+  it('returns 400 when the mapping builder rejects the vat_amount', async () => {
+    mappingMock.mockImplementationOnce(() => {
+      throw new Error('vat_amount 100 exceeds the maximum possible Swedish VAT on 415.8')
+    })
+    enqueue({
+      data: {
+        id: 'op-1',
+        company_id: 'company-1',
+        operation_type: 'categorize_transaction',
+        status: 'pending',
+        params: { transaction_id: 'tx-1', category: 'expense_representation', vat_treatment: 'reduced_12' },
+        preview_data: {},
+        title: '',
+      },
+    })
+    enqueue({ data: { id: 'tx-1', company_id: 'company-1', amount: -415.8, currency: 'SEK' } })
+    enqueue({ data: { entity_type: 'enskild_firma' } })
+
+    const res = await PATCH(
+      createMockRequest('/api/pending-operations/op-1', {
+        method: 'PATCH',
+        body: { vat_amount: 100 },
+      }),
+      createMockRouteParams({ id: 'op-1' }),
+    )
+    const { status, body } = await parseJsonResponse<{ error: string }>(res)
+    expect(status).toBe(400)
+    expect(body.error).toMatch(/exceeds the maximum/)
+  })
+
  it('returns 400 when mapping yields no accounts', async () => {
    enqueue({
      data: {
@@ -4,7 +4,8 @@ import { z } from 'zod'
 import { ensureInitialized } from '@/lib/init'
 import { requireCompanyId } from '@/lib/company/context'
 import { requireWritePermission } from '@/lib/auth/require-write'
-import { buildMappingResultFromCategory } from '@/lib/bookkeeping/category-mapping'
+import { buildMappingResultFromCategory, getCategoryAccountMapping } from '@/lib/bookkeeping/category-mapping'
+import { getVatRate } from '@/lib/bookkeeping/vat-entries'
 import type { EntityType, Transaction, TransactionCategory, VatTreatment } from '@/types'

 // PATCH /api/pending-operations/[id]
@@ -38,9 +39,11 @@ const PatchSchema = z
  .object({
    category: z.enum(CATEGORIES).optional(),
    vat_treatment: z.enum(VAT_TREATMENTS).nullable().optional(),
+    // Underlag's actual VAT override (null clears it; omit to preserve)
+    vat_amount: z.number().min(0).nullable().optional(),
  })
  .refine(
-    (v) => v.category !== undefined || v.vat_treatment !== undefined,
+    (v) => v.category !== undefined || v.vat_treatment !== undefined || v.vat_amount !== undefined,
    { message: 'Nothing to update' },
  )

@@ -129,13 +132,50 @@ export async function PATCH(
  const entityType = ((settings?.entity_type as EntityType) || 'enskild_firma')

  const isBusiness = newCategory !== 'private'
-  const mapping = buildMappingResultFromCategory(
-    newCategory,
-    tx as Transaction,
-    isBusiness,
-    entityType,
-    newVatTreatment,
+
+  // Resolve whether the (possibly defaulted) treatment carries a rate-based
+  // VAT line — only then can a vat_amount override survive. An explicit
+  // override on a VAT-less treatment is a caller error; a preserved one from
+  // before the edit is simply stale and gets dropped.
+  const probe = getCategoryAccountMapping(
+    newCategory, (tx as Transaction).amount, isBusiness, entityType, newVatTreatment,
  )
+  const carriesRateVat =
+    isBusiness &&
+    probe.vatTreatment !== null &&
+    probe.vatTreatment !== 'reverse_charge' &&
+    getVatRate(probe.vatTreatment as VatTreatment) > 0
+
+  let newVatAmount: number | null
+  if (body.vat_amount !== undefined) {
+    if (body.vat_amount !== null && !carriesRateVat) {
+      return NextResponse.json(
+        { error: 'vat_amount kräver en momspliktig vat_treatment (standard_25, reduced_12 eller reduced_6).' },
+        { status: 400 },
+      )
+    }
+    newVatAmount = body.vat_amount
+  } else {
+    const previous = typeof oldParams.vat_amount === 'number' ? oldParams.vat_amount : null
+    newVatAmount = carriesRateVat ? previous : null
+  }
+
+  let mapping
+  try {
+    mapping = buildMappingResultFromCategory(
+      newCategory,
+      tx as Transaction,
+      isBusiness,
+      entityType,
+      newVatTreatment,
+      newVatAmount,
+    )
+  } catch (err) {
+    return NextResponse.json(
+      { error: err instanceof Error ? err.message : 'Ogiltig momsjustering' },
+      { status: 400 },
+    )
+  }

  if (!mapping.debit_account || !mapping.credit_account) {
    return NextResponse.json(
@@ -162,6 +202,7 @@ export async function PATCH(
    ...oldParams,
    category: newCategory,
    vat_treatment: newVatTreatment ?? null,
+    vat_amount: newVatAmount,
  }

  const { data: updated, error } = await supabase