feat(vat): add per-account declaration treatments (#1588)

Closes #1457

app/api/bookkeeping/accounts/[number]/route.ts

@@ -4,6 +4,7 @@ import { validateBody } from '@/lib/api/validate'
 import { sparsePatchBody } from '@/lib/api/sparse-patch'
 import { UpdateAccountSchema } from '@/lib/api/schemas'
 import { getErrorMessage as getUserErrorMessage } from '@/lib/errors/get-error-message'
+import { isVatTreatmentValidForAccountClass } from '@/lib/vat/account-vat-treatment'
 
 // DELETE hard-deletes an unused, non-system account; accounts referenced by
 // this company's journal entries must be deactivated instead (PUT is_active).
@@ -95,7 +96,7 @@ export const PUT = withRouteContext(
     // .default() today, so sparsePatchBody is a no-op here: it is the
     // structural guarantee that adding one later cannot make a PUT that
     // renames an account also rewrite its VAT code or SRU mapping. An
-    // explicit null (clearing sru_code, default_vat_code, default_vat_rate)
+    // explicit null (clearing sru_code, VAT defaults, or descriptions)
     // still survives.
     const validation = await validateBody(request, sparsePatchBody(UpdateAccountSchema), {
       log,
@@ -104,6 +105,19 @@ export const PUT = withRouteContext(
     if (!validation.success) return validation.response
     const body = validation.data
 
+    if (
+      body.default_vat_treatment &&
+      !isVatTreatmentValidForAccountClass(
+        body.default_vat_treatment,
+        Number(number.charAt(0)),
+      )
+    ) {
+      return NextResponse.json(
+        { error: 'Momshanteringen är inte giltig för kontoklassen' },
+        { status: 400 },
+      )
+    }
+
     if (Object.keys(body).length === 0) {
       return NextResponse.json({ error: 'Inget att uppdatera' }, { status: 400 })
     }

app/api/bookkeeping/accounts/__tests__/accounts.test.ts

@@ -267,6 +267,28 @@ describe('POST /api/bookkeeping/accounts', () => {
     }
     expect(insertArg?.default_vat_rate).toBe(0)
   })
+
+  it('forwards default_vat_treatment into the insert', async () => {
+    const { supabase, calls } = createCapturingSupabase([{
+      data: { account_number: '4056', default_vat_treatment: 'reverse_charge_eu_goods' },
+    }])
+    auth(supabase)
+    const req = createMockRequest('/api/bookkeeping/accounts', {
+      method: 'POST',
+      body: {
+        account_number: '4056',
+        account_name: 'Inköp varor EU',
+        account_type: 'expense',
+        normal_balance: 'debit',
+        default_vat_treatment: 'reverse_charge_eu_goods',
+      },
+    })
+    expect((await createPOST(req, routeParams)).status).toBe(200)
+    const insertArg = calls.find((c) => c.method === 'insert')?.args[0] as {
+      default_vat_treatment?: string | null
+    }
+    expect(insertArg.default_vat_treatment).toBe('reverse_charge_eu_goods')
+  })
 })
 
 describe('DELETE /api/bookkeeping/accounts/[number]', () => {
@@ -376,6 +398,33 @@ describe('PUT /api/bookkeeping/accounts/[number]', () => {
     expect(updateArg?.default_vat_rate).toBe(0)
   })
 
+  it('forwards default_vat_treatment into the update', async () => {
+    const { supabase, calls } = createCapturingSupabase([{
+      data: { account_number: '3041', default_vat_treatment: 'standard_25' },
+    }])
+    auth(supabase)
+    const req = createMockRequest('/api/bookkeeping/accounts/3041', {
+      method: 'PUT',
+      body: { default_vat_treatment: 'standard_25' },
+    })
+    expect((await PUT(req, { params: Promise.resolve({ number: '3041' }) })).status).toBe(200)
+    const updateArg = calls.find((c) => c.method === 'update')?.args[0] as {
+      default_vat_treatment?: string | null
+    }
+    expect(updateArg.default_vat_treatment).toBe('standard_25')
+  })
+
+  it('rejects a VAT treatment that does not apply to the account class', async () => {
+    const { supabase, calls } = createCapturingSupabase([])
+    auth(supabase)
+    const req = createMockRequest('/api/bookkeeping/accounts/5010', {
+      method: 'PUT',
+      body: { default_vat_treatment: 'standard_25' },
+    })
+    expect((await PUT(req, numberParams)).status).toBe(400)
+    expect(calls.some((call) => call.method === 'update')).toBe(false)
+  })
+
   // The body is spread straight into .update(), so the write set must be
   // exactly what the caller named. UpdateAccountSchema carries no .default()
   // today; these two lock the property in so adding one cannot turn a rename

app/api/bookkeeping/accounts/route.ts

@@ -104,6 +104,7 @@ export const POST = withRouteContext(
         description: body.description || null,
         default_vat_code: body.default_vat_code || null,
         default_vat_rate: body.default_vat_rate ?? null,
+        default_vat_treatment: body.default_vat_treatment ?? null,
         sru_code: body.sru_code || null,
         sort_order: parseInt(body.account_number),
       })

app/api/reports/vat-declaration/ruta/[ruta]/sources/__tests__/route.test.ts

@@ -31,10 +31,19 @@ function buildSupabase(
   chartAccounts: Array<{
     account_number: string
     account_name?: string
+    account_class?: number
     default_vat_rate: number | null
+    default_vat_treatment?: string | null
   }> = []
 ): SupabaseShape {
-  const chartResult = { data: chartAccounts, error: null }
+  const chartResult = {
+    data: chartAccounts.map((account) => ({
+      account_class: 3,
+      default_vat_treatment: null,
+      ...account,
+    })),
+    error: null,
+  }
   return {
     rpc: vi.fn().mockResolvedValue(linesResult),
     from: vi.fn().mockImplementation((table: string) => {
@@ -44,6 +53,8 @@ function buildSupabase(
         return {
           select: vi.fn().mockReturnThis(),
           eq: vi.fn().mockReturnThis(),
+          gte: vi.fn().mockReturnThis(),
+          lte: vi.fn().mockReturnThis(),
           in: vi.fn().mockReturnThis(),
           not: vi.fn().mockReturnThis(),
           order: vi.fn().mockReturnThis(),
@@ -228,7 +239,7 @@ describe('GET /api/reports/vat-declaration/ruta/[ruta]/sources', () => {
   })
 })
 
-describe('GET /api/reports/vat-declaration/ruta/[ruta]/sources: ruta 05 accounts', () => {
+describe('GET /api/reports/vat-declaration/ruta/[ruta]/sources: account overrides', () => {
   /** The p_accounts array the route handed to get_vat_ruta_source_lines. */
   function rpcAccounts(supabase: SupabaseShape): string[] {
     return (supabase.rpc.mock.calls[0][1] as { p_accounts: string[] }).p_accounts
@@ -280,7 +291,23 @@ describe('GET /api/reports/vat-declaration/ruta/[ruta]/sources: ruta 05 accounts
     const accounts = rpcAccounts(supabase)
     expect(accounts).toContain('2611')
     expect(accounts).not.toContain('3013')
-    expect(supabase.from).not.toHaveBeenCalledWith('chart_of_accounts')
+    // Every ruta resolves explicit account overrides before the static BAS
+    // fallback, but a ruta 05-only custom account still stays out of ruta 10.
+    expect(supabase.from).toHaveBeenCalledWith('chart_of_accounts')
+  })
+
+  it('drills into a custom EU purchase account in ruta 20', async () => {
+    const supabase = buildSupabase({ data: [], error: null }, { data: null, error: null }, [{
+      account_number: '4056',
+      account_name: 'Inköp varor 25% EU',
+      account_class: 4,
+      default_vat_rate: 0.25,
+      default_vat_treatment: 'reverse_charge_eu_goods',
+    }])
+    authOk(supabase)
+
+    expect((await get('20')).status).toBe(200)
+    expect(rpcAccounts(supabase)).toContain('4056')
   })
 })
 

app/api/reports/vat-declaration/ruta/[ruta]/sources/route.ts

@@ -4,7 +4,7 @@ import {
   ACCOUNT_RUTA,
   resolvePeriodDates,
 } from '@/lib/reports/vat-declaration'
-import { fetchDynamicRuta05Accounts } from '@/lib/reports/vat-revenue-accounts'
+import { fetchDynamicVatAccounts } from '@/lib/reports/vat-revenue-accounts'
 import type { ReportSourceLine } from '@/lib/reports/source-lines'
 import type { VatDeclarationRutor, VatPeriodType } from '@/types'
 
@@ -40,17 +40,17 @@ export const GET = withRouteContext<{ params: Promise<{ ruta: string }> }>(
     rutaParam.startsWith('ruta') ? rutaParam : `ruta${rutaParam}`
   ) as keyof VatDeclarationRutor
 
-  // Invert ACCOUNT_RUTA: which BAS accounts feed this ruta?
+  const dynamicVatAccounts = await fetchDynamicVatAccounts(supabase, companyId)
+
+  // Invert the effective mapping. Fixed BAS mappings stay authoritative;
+  // explicit treatments add custom accounts only.
   const accountsForRuta = Object.entries(ACCOUNT_RUTA)
     .filter(([, m]) => m.box === rutaKey)
     .map(([acc]) => acc)
 
-  // Ruta 05 also collects the company's own momspliktiga intäktskonton, which
-  // ACCOUNT_RUTA cannot know about (#1261). Without them the drill-down would
-  // list a smaller sum than the figure it drills into.
-  if (rutaKey === 'ruta05') {
-    const { accounts } = await fetchDynamicRuta05Accounts(supabase, companyId)
-    accountsForRuta.push(...accounts)
+  for (const [account, mapping] of dynamicVatAccounts.mappingByAccount) {
+    if (ACCOUNT_RUTA[account]) continue
+    if (mapping.box === rutaKey) accountsForRuta.push(account)
   }
 
   if (accountsForRuta.length === 0) {