feat(mcp): Belegvorbereitung für Eingangsrechnungen anstoßen

- accounting.incoming_invoices.prepare startet die Vorbereitung für alle offenen oder ausgewählte Dateien und liefert angelegte Entwürfe samt Validierung sowie übersprungene Dateien
- Vorbereitungslauf meldet sein Ergebnis und läuft je Mandant nacheinander, damit parallele Aufrufe keine doppelten Belege anlegen

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

backend/src/mcp/tools/accounting.ts

@@ -1,6 +1,6 @@
 import { outgoingAddressSchema, outgoingRowsSchema, outgoingReportSchema } from "../documentSchemas"
 import { limitFromArgs, offsetFromArgs, paginatedResult, paginationProperties } from "../pagination"
-import { and, desc, eq, ilike, or } from "drizzle-orm"
+import { and, desc, eq, ilike, inArray, or } from "drizzle-orm"
 import { randomUUID } from "node:crypto"
 import { validateBankAllocationCostCentre } from "../../modules/bank-allocation-details"
 import {
@@ -1154,6 +1154,62 @@ export const accountingTools: McpTool[] = [
             return validateIncomingInvoiceData(rows[0] as Record<string, any>)
         },
     },
+    {
+        name: "accounting.incoming_invoices.prepare",
+        title: "Belegvorbereitung starten",
+        description: "Startet die Belegvorbereitung wie der Button „Belege vorbereiten“: Dateien vom Typ Eingangsrechnung ohne verknüpften Beleg werden ausgelesen (strukturierte E-Rechnung, sonst KI) und als Eingangsbeleg-Entwurf angelegt. Optional nur für bestimmte Datei-IDs. Kann je Datei einige Sekunden dauern.",
+        requiredPermissions: ["accounting.incoming_invoices.write"],
+        inputSchema: {
+            type: "object",
+            properties: {
+                fileIds: {
+                    type: "array",
+                    items: { type: "string", format: "uuid" },
+                    minItems: 1,
+                    maxItems: 50,
+                    description: "Optionale Datei-IDs; ohne Angabe alle offenen Eingangsrechnungsdateien.",
+                },
+            },
+            additionalProperties: false,
+        },
+        async handler(context, args) {
+            let fileIds: string[] | undefined
+            if (args.fileIds !== undefined) {
+                if (!Array.isArray(args.fileIds) || !args.fileIds.length || args.fileIds.length > 50) {
+                    throw new Error("fileIds muss 1 bis 50 Datei-IDs enthalten")
+                }
+                if (args.fileIds.some((id) => typeof id !== "string" || !UUID_PATTERN.test(id))) {
+                    throw new Error("fileIds darf nur gültige UUIDs enthalten")
+                }
+                fileIds = [...new Set((args.fileIds as string[]).map((id) => id.toLowerCase()))]
+            }
+
+            const result = await context.server.services.prepareIncomingInvoices.run(context.tenantId, { fileIds })
+            if (result.error && !result.filesFound) throw new Error(result.error)
+
+            const invoiceIds = result.created.map((entry) => entry.invoiceId)
+            const invoices = invoiceIds.length
+                ? await context.server.db
+                    .select()
+                    .from(incominginvoices)
+                    .where(and(eq(incominginvoices.tenant, context.tenantId), inArray(incominginvoices.id, invoiceIds)))
+                : []
+            const handled = new Set([...result.created, ...result.skipped].map((entry) => entry.fileId))
+
+            return {
+                filesFound: result.filesFound,
+                created: result.created.map((entry) => {
+                    const invoice = invoices.find((row) => row.id === entry.invoiceId) || null
+                    return { ...entry, invoice, validation: invoice ? validateIncomingInvoiceData(invoice as Record<string, any>) : null }
+                }),
+                skipped: [
+                    ...result.skipped,
+                    ...(fileIds || []).filter((id) => !handled.has(id))
+                        .map((fileId) => ({ fileId, reason: "Keine offene Eingangsrechnungsdatei (nicht gefunden, archiviert, anderer Dateityp oder bereits vorbereitet)" })),
+                ],
+            }
+        },
+    },
     {
         name: "accounting.incoming_invoices.create",
         title: "Eingangsbeleg erstellen",

backend/src/modules/cron/prepareIncomingInvoices.ts

@@ -17,7 +17,7 @@ import {
     incominginvoices,
 } from "../../../db/schema"
 
-import { eq, and, isNull, not } from "drizzle-orm"
+import { eq, and, inArray, isNull, not } from "drizzle-orm"
 
 const formatInvoiceItemDescription = (item: any) => {
     const parts = [
@@ -86,8 +86,16 @@ const mapGptDataToIncomingInvoice = (data: any, tenantId: number) => {
     return itemInfo
 }
 
+export type IncomingInvoicePreparationResult = {
+    filesFound: number
+    created: Array<{ fileId: string, invoiceId: number, source: string | null }>
+    skipped: Array<{ fileId: string, reason: string }>
+    error?: string
+}
+
 export function prepareIncomingInvoices(server: FastifyInstance) {
-    const processInvoices = async (tenantId:number) => {
+    const processInvoices = async (tenantId:number, fileIds?: string[]) => {
+        const result: IncomingInvoicePreparationResult = { filesFound: 0, created: [], skipped: [] }
         console.log("▶ Starting Incoming Invoice Preparation")
 
         const tenantsRes = await server.db
@@ -98,7 +106,7 @@ export function prepareIncomingInvoices(server: FastifyInstance) {
 
         if (!tenantsRes.length) {
             console.log("No tenants with autoPrepareIncomingInvoices = true")
-            return
+            return { ...result, error: "Mandant nicht gefunden" }
         }
 
         console.log(`Processing tenants: ${tenantsRes.map(t => t.id).join(", ")}`)
@@ -124,6 +132,7 @@ export function prepareIncomingInvoices(server: FastifyInstance) {
             const invoiceFileTag = tagRes?.[0]?.id
             if (!invoiceFileTag) {
                 server.log.error(`❌ Missing filetag 'invoices' for tenant ${tenantId}`)
+                result.error = "Dateityp für Eingangsrechnungen fehlt"
                 continue
             }
 
@@ -137,10 +146,13 @@ export function prepareIncomingInvoices(server: FastifyInstance) {
                         eq(files.type, invoiceFileTag),
                         isNull(files.incominginvoice),
                         eq(files.archived, false),
-                        not(isNull(files.path))
+                        not(isNull(files.path)),
+                        ...(fileIds ? [inArray(files.id, fileIds)] : [])
                     )
                 )
 
+            result.filesFound += filesRes.length
+
             if (!filesRes.length) {
                 console.log(`No invoice files for tenant ${tenantId}`)
                 continue
@@ -158,6 +170,7 @@ export function prepareIncomingInvoices(server: FastifyInstance) {
                     fileData = await loadFileBuffer(file.path!)
                 } catch (error) {
                     server.log.error(error, `Datei ${file.id} konnte nicht aus S3 geladen werden.`)
+                    result.skipped.push({ fileId: file.id, reason: "Datei konnte nicht geladen werden" })
                     continue
                 }
 
@@ -186,7 +199,10 @@ export function prepareIncomingInvoices(server: FastifyInstance) {
                     } catch (error) {
                         server.log.error(error, `E-Rechnung aus Datei ${file.id} konnte nicht verarbeitet werden.`)
 
-                        if (electronicInvoice.container === "xml") continue
+                        if (electronicInvoice.container === "xml") {
+                            result.skipped.push({ fileId: file.id, reason: "E-Rechnung konnte nicht verarbeitet werden" })
+                            continue
+                        }
                     }
                 }
 
@@ -195,6 +211,7 @@ export function prepareIncomingInvoices(server: FastifyInstance) {
 
                     if (!data) {
                         server.log.warn(`GPT returned no data for file ${file.id}`)
+                        result.skipped.push({ fileId: file.id, reason: "Keine Belegdaten erkannt" })
                         continue
                     }
 
@@ -213,6 +230,7 @@ export function prepareIncomingInvoices(server: FastifyInstance) {
 
                 if (!newInvoice) {
                     server.log.error(`Failed to insert incoming invoice for file ${file.id}`)
+                    result.skipped.push({ fileId: file.id, reason: "Eingangsbeleg konnte nicht angelegt werden" })
                     continue
                 }
 
@@ -224,20 +242,31 @@ export function prepareIncomingInvoices(server: FastifyInstance) {
                     .set({ incominginvoice: newInvoice.id })
                     .where(eq(files.id, file.id))
 
+                result.created.push({ fileId: file.id, invoiceId: newInvoice.id, source: newInvoice.preparationSource ?? null })
                 console.log(`IncomingInvoice ${newInvoice.id} created for file ${file.id}`)
             }
 
         }
 
 
-        return
+        return result
     }
 
-    return {
-        run: async (tenant:number) => {
-            await processInvoices(tenant)
-            console.log("Incoming Invoice Preparation Completed.")
+    // Serialize runs per tenant so concurrent triggers cannot prepare the same file twice.
+    const running = new Map<number, Promise<unknown>>()
 
+    return {
+        run: async (tenant:number, options: { fileIds?: string[] } = {}) => {
+            const previous = running.get(tenant) || Promise.resolve()
+            const current = previous.catch(() => undefined).then(() => processInvoices(tenant, options.fileIds))
+            running.set(tenant, current)
+            try {
+                const result = await current
+                console.log("Incoming Invoice Preparation Completed.")
+                return result
+            } finally {
+                if (running.get(tenant) === current) running.delete(tenant)
+            }
         }
     }
 

backend/tests/mcpIncomingInvoicePreparation.test.ts

@@ -0,0 +1,41 @@
+import assert from "node:assert/strict"
+import test from "node:test"
+import { mcpToolMap } from "../src/mcp/registry"
+
+const fileA = "00000000-0000-4000-8000-00000000000a"
+const fileB = "00000000-0000-4000-8000-00000000000b"
+const tool = mcpToolMap.get("accounting.incoming_invoices.prepare")!
+
+function context(result: any, invoices: any[] = []) {
+    const calls: any[] = []
+    const db: any = {
+        select: () => ({ from: () => ({ where: async () => invoices }) }),
+    }
+    const services = { prepareIncomingInvoices: { run: async (tenantId: number, options: any) => { calls.push({ tenantId, options }); return result } } }
+    return { calls, context: { server: { db, services }, tenantId: 7, userId: "user", isAdmin: true, permissions: [] } as any }
+}
+
+test("prepare runs for the active tenant and returns created drafts with validation", async () => {
+    const invoice = { id: 11, tenant: 7, state: "Entwurf", archived: false }
+    const { calls, context: ctx } = context({ filesFound: 1, created: [{ fileId: fileA, invoiceId: 11, source: "gpt" }], skipped: [] }, [invoice])
+    const result: any = await tool.handler(ctx, {})
+    assert.deepEqual(calls, [{ tenantId: 7, options: { fileIds: undefined } }])
+    assert.equal(result.created[0].invoice.id, 11)
+    assert.ok(result.created[0].validation)
+    assert.deepEqual(result.skipped, [])
+})
+
+test("prepare limits to given files and reports files it could not handle", async () => {
+    const { calls, context: ctx } = context({ filesFound: 1, created: [], skipped: [{ fileId: fileA, reason: "Keine Belegdaten erkannt" }] })
+    const result: any = await tool.handler(ctx, { fileIds: [fileA, fileB.toUpperCase(), fileB] })
+    assert.deepEqual(calls[0].options.fileIds, [fileA, fileB])
+    assert.deepEqual(result.skipped.map((entry: any) => entry.fileId), [fileA, fileB])
+})
+
+test("prepare validates input and surfaces tenant configuration errors", async () => {
+    const { context: ctx } = context({ filesFound: 0, created: [], skipped: [], error: "Dateityp für Eingangsrechnungen fehlt" })
+    await assert.rejects(tool.handler(ctx, { fileIds: [] }), /1 bis 50/)
+    await assert.rejects(tool.handler(ctx, { fileIds: ["abc"] }), /UUID/)
+    await assert.rejects(tool.handler(ctx, {}), /Dateityp für Eingangsrechnungen fehlt/)
+    assert.deepEqual(tool.requiredPermissions, ["accounting.incoming_invoices.write"])
+})