feat(accounting): Kostenstellen von Eingangsbelegen jederzeit nachträglich ändern

Eigener Endpunkt und MCP-Tool ändern ausschließlich die Positionskostenstellen,
auch bei gebuchten oder einer Bankbuchung zugewiesenen Eingangsbelegen.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

backend/src/mcp/tools/accounting.ts

@@ -22,6 +22,7 @@ import { saveFile } from "../../utils/files"
 import { insertHistoryItem } from "../../utils/history"
 import { executeManualGeneration, finishManualGeneration } from "../../modules/serialexecution.service"
 import { updateOutgoingDocumentCostCentres } from "../../modules/outgoing-document-cost-centres.service"
+import { updateIncomingInvoiceCostCentres } from "../../modules/incoming-invoice-cost-centres.service"
 import { loadBankBalances } from "../../modules/bank-balances.service"
 import { dateField } from "../masterdataFields"
 import {
@@ -1287,6 +1288,44 @@ export const accountingTools: McpTool[] = [
             return { invoice: updated, validation: validateIncomingInvoiceData(updated as Record<string, any>) }
         },
     },
+    {
+        name: "accounting.incoming_invoices.cost_centres.update",
+        title: "Kostenstellen eines Eingangsbelegs ändern",
+        description: "Ändert ausschließlich die Positionskostenstellen eines Eingangsbelegs, auch wenn er gebucht oder einer Bankbuchung zugewiesen ist.",
+        requiredPermissions: ["accounting.incoming_invoices.write"],
+        inputSchema: {
+            type: "object",
+            required: ["id", "accountCostCentres"],
+            properties: {
+                id: { type: "number" },
+                accountCostCentres: {
+                    type: "array",
+                    minItems: 1,
+                    items: {
+                        type: "object",
+                        required: ["index", "costcentre"],
+                        properties: {
+                            index: { type: "integer", minimum: 0, description: "Nullbasierter Index der Position in accounts." },
+                            costcentre: { type: ["string", "null"], description: "UUID der Positionskostenstelle oder null." },
+                        },
+                    },
+                },
+            },
+        },
+        async handler(context, args) {
+            const id = numberArg(args, "id")
+            if (!id) throw new Error("id ist erforderlich")
+
+            const invoice = await updateIncomingInvoiceCostCentres(
+                context.server,
+                context.tenantId,
+                context.userId,
+                id,
+                { accountCostCentres: args.accountCostCentres as any },
+            )
+            return { invoice }
+        },
+    },
     {
         name: "accounting.incoming_invoices.book",
         title: "Eingangsbeleg buchen",

backend/src/modules/incoming-invoice-cost-centres.service.ts

@@ -0,0 +1,126 @@
+import { and, eq, inArray } from "drizzle-orm"
+import { FastifyInstance } from "fastify"
+import { costcentres, incominginvoices } from "../../db/schema"
+import { insertHistoryItem } from "../utils/history"
+
+export type AccountCostCentreAssignment = {
+    index: number
+    costcentre: string | null
+}
+
+export type IncomingInvoiceCostCentreUpdate = {
+    accountCostCentres?: AccountCostCentreAssignment[]
+}
+
+const serviceError = (message: string, statusCode = 400) =>
+    Object.assign(new Error(message), { statusCode })
+const UUID_PATTERN = /^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i
+
+export function normalizeAccountCostCentreAssignments(input: unknown): AccountCostCentreAssignment[] {
+    if (!Array.isArray(input)) throw serviceError("accountCostCentres muss ein Array sein")
+    if (!input.length) throw serviceError("Mindestens eine Positionskostenstelle ist erforderlich")
+
+    const seen = new Set<number>()
+    return input.map((assignment) => {
+        const index = assignment?.index
+        const costcentre = assignment?.costcentre
+        if (!Number.isInteger(index) || index < 0) throw serviceError("Jede Positionszuordnung benötigt einen gültigen index")
+        if (seen.has(index)) throw serviceError(`Position ${index + 1} ist mehrfach angegeben`)
+        seen.add(index)
+        if (costcentre !== null && (typeof costcentre !== "string" || !UUID_PATTERN.test(costcentre))) {
+            throw serviceError(`Ungültige Kostenstelle für Position ${index + 1}`)
+        }
+        return { index, costcentre }
+    })
+}
+
+export function applyAccountCostCentreAssignments(
+    accounts: unknown,
+    assignments: AccountCostCentreAssignment[] = [],
+) {
+    if (!Array.isArray(accounts)) throw serviceError("Der Eingangsbeleg enthält keine Positionen")
+
+    for (const { index } of assignments) {
+        const account = accounts[index]
+        if (!account || typeof account !== "object" || Array.isArray(account)) {
+            throw serviceError(`Position ${index + 1} wurde im Eingangsbeleg nicht gefunden`)
+        }
+    }
+
+    const assignmentMap = new Map(assignments.map((assignment) => [assignment.index, assignment.costcentre]))
+    return accounts.map((account, index) => {
+        if (!assignmentMap.has(index)) return account
+        const { costcentre: _legacyCostCentre, ...rest } = account as Record<string, unknown>
+        return { ...rest, costCentre: assignmentMap.get(index) ?? null }
+    })
+}
+
+export async function updateIncomingInvoiceCostCentres(
+    server: FastifyInstance,
+    tenantId: number,
+    userId: string,
+    invoiceId: number,
+    input: IncomingInvoiceCostCentreUpdate,
+) {
+    const assignments = normalizeAccountCostCentreAssignments(input?.accountCostCentres)
+
+    const [existing] = await server.db
+        .select()
+        .from(incominginvoices)
+        .where(and(
+            eq(incominginvoices.id, invoiceId),
+            eq(incominginvoices.tenant, tenantId),
+            eq(incominginvoices.archived, false),
+        ))
+        .limit(1)
+
+    if (!existing) throw serviceError("Eingangsbeleg nicht gefunden", 404)
+
+    const referencedCostCentreIds = [...new Set(
+        assignments.map((assignment) => assignment.costcentre).filter((id): id is string => Boolean(id)),
+    )]
+
+    if (referencedCostCentreIds.length) {
+        const validCostCentres = await server.db
+            .select({ id: costcentres.id })
+            .from(costcentres)
+            .where(and(
+                eq(costcentres.tenant, tenantId),
+                eq(costcentres.archived, false),
+                inArray(costcentres.id, referencedCostCentreIds),
+            ))
+
+        if (validCostCentres.length !== referencedCostCentreIds.length) {
+            throw serviceError("Mindestens eine Kostenstelle wurde nicht gefunden oder ist archiviert")
+        }
+    }
+
+    const [updated] = await server.db
+        .update(incominginvoices)
+        .set({
+            accounts: applyAccountCostCentreAssignments(existing.accounts, assignments),
+            updatedAt: new Date(),
+            updatedBy: userId,
+        })
+        .where(and(
+            eq(incominginvoices.id, invoiceId),
+            eq(incominginvoices.tenant, tenantId),
+            eq(incominginvoices.archived, false),
+        ))
+        .returning()
+
+    if (!updated) throw serviceError("Eingangsbeleg nicht gefunden", 404)
+
+    await insertHistoryItem(server, {
+        tenant_id: tenantId,
+        created_by: userId,
+        entity: "incominginvoices",
+        entityId: invoiceId,
+        action: "updated",
+        oldVal: existing,
+        newVal: updated,
+        text: "Kostenstellen des Eingangsbelegs geändert",
+    })
+
+    return updated
+}

backend/src/routes/functions.ts

@@ -22,6 +22,7 @@ import {citys, files} from "../../db/schema";
 import {and, eq, isNull, not} from "drizzle-orm";
 import {cancelManualGeneration, executeManualGeneration, finishManualGeneration} from "../modules/serialexecution.service";
 import { updateOutgoingDocumentCostCentres } from "../modules/outgoing-document-cost-centres.service";
+import { updateIncomingInvoiceCostCentres } from "../modules/incoming-invoice-cost-centres.service";
 import { s3 } from "../utils/s3";
 import { secrets } from "../utils/secrets";
 import { storeExtractedTextForFile } from "../utils/documentText";
@@ -334,6 +335,26 @@ export default async function functionRoutes(server: FastifyInstance) {
         }
     })
 
+    server.put('/functions/incoming-invoices/:id/cost-centres', async (req, reply) => {
+        try {
+            const { id } = req.params as { id: string }
+            const invoiceId = Number(id)
+            if (!Number.isFinite(invoiceId)) return reply.code(400).send({ error: "Ungültige Eingangsbeleg-ID" })
+
+            const invoice = await updateIncomingInvoiceCostCentres(
+                server,
+                req.user.tenant_id,
+                req.user.user_id,
+                invoiceId,
+                req.body as any,
+            )
+            return { invoice }
+        } catch (error) {
+            const statusCode = (error as any)?.statusCode || 500
+            return reply.code(statusCode).send({ error: error instanceof Error ? error.message : "Kostenstellen konnten nicht geändert werden" })
+        }
+    })
+
     server.post('/functions/services/bankstatementsync', async (req, reply) => {
         const result = await server.services.bankStatements.run(req.user.tenant_id);
         if (result.errors.length > 0) {

backend/tests/incomingInvoiceCostCentres.test.ts

@@ -0,0 +1,48 @@
+import assert from "node:assert/strict"
+import test from "node:test"
+import {
+    applyAccountCostCentreAssignments,
+    normalizeAccountCostCentreAssignments,
+} from "../src/modules/incoming-invoice-cost-centres.service"
+import { mcpToolMap } from "../src/mcp/registry"
+
+const CENTRE = "8f1c2b3a-4d5e-4f60-8a7b-9c0d1e2f3a4b"
+
+test("changes only requested account cost centres", () => {
+    const accounts = [
+        { account: 1, amountNet: 100, taxType: "19", costCentre: "old-1" },
+        { account: 2, amountNet: 50, taxType: "7", costCentre: "old-2" },
+    ]
+
+    assert.deepEqual(applyAccountCostCentreAssignments(accounts, [
+        { index: 1, costcentre: CENTRE },
+    ]), [
+        accounts[0],
+        { account: 2, amountNet: 50, taxType: "7", costCentre: CENTRE },
+    ])
+})
+
+test("rejects assignments for unknown invoice positions", () => {
+    assert.throws(
+        () => applyAccountCostCentreAssignments([{ account: 1 }], [{ index: 3, costcentre: null }]),
+        /Position 4.*nicht gefunden/,
+    )
+})
+
+test("validates cost centre assignments", () => {
+    assert.throws(() => normalizeAccountCostCentreAssignments([]), /Mindestens eine/)
+    assert.throws(() => normalizeAccountCostCentreAssignments([{ index: -1, costcentre: null }]), /gültigen index/)
+    assert.throws(() => normalizeAccountCostCentreAssignments([{ index: 0, costcentre: "x" }]), /Ungültige Kostenstelle/)
+    assert.throws(
+        () => normalizeAccountCostCentreAssignments([{ index: 0, costcentre: null }, { index: 0, costcentre: CENTRE }]),
+        /mehrfach/,
+    )
+    assert.deepEqual(normalizeAccountCostCentreAssignments([{ index: 0, costcentre: CENTRE }]), [{ index: 0, costcentre: CENTRE }])
+})
+
+test("registers a dedicated incoming invoice cost centre tool", () => {
+    const tool = mcpToolMap.get("accounting.incoming_invoices.cost_centres.update")
+
+    assert.deepEqual(tool?.requiredPermissions, ["accounting.incoming_invoices.write"])
+    assert.deepEqual(tool?.inputSchema.required, ["id", "accountCostCentres"])
+})