Merge pull request 'dev' (#257) from dev into main

Reviewed-on: #257

.gitea/ISSUE_TEMPLATE/bug_report.md

@@ -2,37 +2,18 @@
 name: 🐛 Bug Report
 about: Erstelle einen Bericht, um uns zu helfen, das Projekt zu verbessern.
 title: '[BUG] '
-labels: bug
+labels: Problem
 assignees: ''
 
 ---
 
 **Beschreibung**
-Eine klare und prägnante Beschreibung des Fehlers.
+
 
 **Reproduktion**
-Schritte, um den Fehler zu reproduzieren:
 
-Entweder:
-1. Gehe zu '...'
-2. Klicke auf '...'
-3. Scrolle runter zu '...'
-4. Siehe Fehler
-
-Oder Link zur Seite
-
-**Erwartetes Verhalten**
-Eine klare Beschreibung dessen, was du erwartet hast.
 
 **Screenshots**
-Falls zutreffend, füge hier Screenshots oder Gifs hinzu, um das Problem zu verdeutlichen. 
+
 
 **Achtung: Achte bitte auf Datenschutz deiner Daten sowie der Daten deiner Kunden. Sollten ein Screenshot nur mit Daten möglich sein, schwärze diese bitte vor dem Upload.**
-
-**Umgebung:**
-- Betriebssystem: [z.B. Windows, macOS, Linux]
-- Browser / Version (falls relevant): [z.B. Chrome 120]
-- Projekt-Version: [z.B. v1.0.2]
-
-**Zusätzlicher Kontext**
-Füge hier alle anderen Informationen zum Problem hinzu.

.gitea/ISSUE_TEMPLATE/feature_request.md

@@ -2,19 +2,16 @@
 name: ✨ Feature Request
 about: Schlage eine Idee für dieses Projekt vor.
 title: '[FEATURE] '
-labels: enhancement
+labels: Funktionswunsch
 assignees: ''
 
 ---
 
 **Ist dein Feature-Wunsch mit einem Problem verbunden?**
-Eine klare Beschreibung des Problems (z.B. "Ich bin immer genervt, wenn...").
+
 
 **Lösungsvorschlag**
-Eine klare Beschreibung dessen, was du dir wünschst und wie es funktionieren soll.
+
 
 **Alternativen**
-Hast du über alternative Lösungen oder Workarounds nachgedacht?
 
-**Zusätzlicher Kontext**
-Hier ist Platz für weitere Informationen, Skizzen oder Beispiele von anderen Tools.

backend/db/migrations/0084_cash_discounts.sql

@@ -0,0 +1,5 @@
+ALTER TABLE "tenants" ADD COLUMN "cashDiscountAccounts" jsonb DEFAULT '{}'::jsonb NOT NULL;
+--> statement-breakpoint
+ALTER TABLE "statementallocations" ADD COLUMN "cash_discount_amount" double precision;
+--> statement-breakpoint
+ALTER TABLE "statementallocations" ADD COLUMN "cash_discount_split" jsonb;

backend/db/migrations/0085_cash_discount_terms.sql

@@ -0,0 +1,15 @@
+ALTER TABLE "createddocuments" ADD COLUMN "cashDiscountPercent" double precision;
+--> statement-breakpoint
+ALTER TABLE "createddocuments" ADD COLUMN "cashDiscountDays" smallint;
+--> statement-breakpoint
+ALTER TABLE "incominginvoices" ADD COLUMN "cashDiscountPercent" double precision;
+--> statement-breakpoint
+ALTER TABLE "incominginvoices" ADD COLUMN "cashDiscountDueDate" text;
+--> statement-breakpoint
+ALTER TABLE "customers" ADD COLUMN "customCashDiscountPercent" double precision;
+--> statement-breakpoint
+ALTER TABLE "customers" ADD COLUMN "customCashDiscountDays" smallint;
+--> statement-breakpoint
+ALTER TABLE "vendors" ADD COLUMN "cashDiscountPercent" double precision;
+--> statement-breakpoint
+ALTER TABLE "vendors" ADD COLUMN "cashDiscountDays" smallint;

backend/db/migrations/meta/_journal.json

@@ -568,6 +568,20 @@
       "when": 1792022400001,
       "tag": "0083_collaboration_notifications",
       "breakpoints": true
+    },
+    {
+      "idx": 81,
+      "version": "7",
+      "when": 1792108800001,
+      "tag": "0084_cash_discounts",
+      "breakpoints": true
+    },
+    {
+      "idx": 82,
+      "version": "7",
+      "when": 1792195200001,
+      "tag": "0085_cash_discount_terms",
+      "breakpoints": true
     }
   ]
 }

backend/db/schema/createddocuments.ts

@@ -71,6 +71,8 @@ export const createddocuments = pgTable("createddocuments", {
 
     deliveryDateType: text("deliveryDateType"),
     paymentDays: smallint("paymentDays"),
+    cashDiscountPercent: doublePrecision("cashDiscountPercent"),
+    cashDiscountDays: smallint("cashDiscountDays"),
     deliveryDate: text("deliveryDate"),
 
     contactPerson: uuid("contactPerson"),

backend/db/schema/customers.ts

@@ -7,6 +7,7 @@ import {
     jsonb,
     smallint,
     uuid,
+    doublePrecision,
 } from "drizzle-orm/pg-core"
 import { tenants } from "./tenants"
 import { authUsers } from "./auth_users"
@@ -41,6 +42,8 @@ export const customers = pgTable(
         profiles: jsonb("profiles").notNull().default([]),
 
         customPaymentDays: smallint("customPaymentDays"),
+        customCashDiscountPercent: doublePrecision("customCashDiscountPercent"),
+        customCashDiscountDays: smallint("customCashDiscountDays"),
 
         firstname: text("firstname"),
         lastname: text("lastname"),

backend/db/schema/incominginvoices.ts

@@ -7,6 +7,7 @@ import {
     jsonb,
     numeric,
     uuid,
+    doublePrecision,
 } from "drizzle-orm/pg-core"
 
 import { vendors } from "./vendors"
@@ -36,6 +37,8 @@ export const incominginvoices = pgTable("incominginvoices", {
     document: bigint("document", { mode: "number" }),
 
     dueDate: text("dueDate"),
+    cashDiscountPercent: doublePrecision("cashDiscountPercent"),
+    cashDiscountDueDate: text("cashDiscountDueDate"),
 
     description: text("description"),
 

backend/db/schema/statementallocations.ts

@@ -7,6 +7,7 @@ import {
     timestamp,
     boolean,
     doublePrecision,
+    jsonb,
 } from "drizzle-orm/pg-core"
 
 import { tenants } from "./tenants"
@@ -30,6 +31,10 @@ export const statementallocations = pgTable("statementallocations", {
 
     amount: doublePrecision("amount").notNull().default(0),
 
+    // Skonto mit dem Vorzeichen der Zahlung; amount bleibt der tatsächlich gezahlte Betrag.
+    cashDiscountAmount: doublePrecision("cash_discount_amount"),
+    cashDiscountSplit: jsonb("cash_discount_split"),
+
     incominginvoice: bigint("ii_id", { mode: "number" }).references(
         () => incominginvoices.id
     ),

backend/db/schema/tenants.ts

@@ -154,6 +154,8 @@ export const tenants = pgTable(
             }),
         accountChart: text("accountChart").notNull().default("skr03"),
 
+        cashDiscountAccounts: jsonb("cashDiscountAccounts").notNull().default({}),
+
         standardEmailForInvoices: text("standardEmailForInvoices"),
 
         extraModules: jsonb("extraModules").notNull().default([]),

backend/db/schema/vendors.ts

@@ -6,6 +6,8 @@ import {
     boolean,
     jsonb,
     uuid,
+    doublePrecision,
+    smallint,
 } from "drizzle-orm/pg-core"
 
 import { tenants } from "./tenants"
@@ -36,6 +38,8 @@ export const vendors = pgTable("vendors", {
     archived: boolean("archived").notNull().default(false),
 
     defaultPaymentMethod: text("defaultPaymentMethod"),
+    cashDiscountPercent: doublePrecision("cashDiscountPercent"),
+    cashDiscountDays: smallint("cashDiscountDays"),
 
     updatedAt: timestamp("updated_at", { withTimezone: true }),
     updatedBy: uuid("updated_by").references(() => authUsers.id),

backend/package.json

@@ -9,7 +9,7 @@
     "fill": "ts-node src/webdav/fill-file-sizes.ts",
     "dev:dav": "tsx watch src/webdav/server.ts",
     "build": "tsc",
-    "test:einvoice": "tsx --test tests/einvoice.test.ts",
+    "test:einvoice": "tsx --test tests/einvoice.test.ts tests/zugferdInvoice.test.ts",
     "start": "node dist/src/index.js",
     "schema:index": "ts-node scripts/generate-schema-index.ts",
     "bankcodes:update": "tsx scripts/generate-de-bank-codes.ts",

backend/src/mcp/statementAllocations.ts

@@ -55,6 +55,14 @@ export const prepareStatementAllocationInput = (args: Record<string, unknown>) =
     if (!bookingModes.has(bookingMode)) throw new Error(`Ungültige Aufwandsart: ${bookingMode}`)
 
     payload.amount = amount
+    if (hasValue(args.cashDiscountAmount)) {
+        const cashDiscountAmount = Number(args.cashDiscountAmount)
+        if (!Number.isFinite(cashDiscountAmount)) throw new Error("cashDiscountAmount muss eine gültige Zahl sein")
+        if (cashDiscountAmount !== 0) {
+            if (!hasValue(args.bankstatement)) throw new Error("Skonto ist nur zusammen mit einer Bankzahlung möglich")
+            payload.cashDiscountAmount = cashDiscountAmount
+        }
+    }
     if (args.description !== undefined) payload.description = stringArg(args, "description")
     payload.bookingMode = bookingMode
     if (args.datevTaxKey !== undefined) payload.datevTaxKey = stringArg(args, "datevTaxKey")

backend/src/mcp/tools/accounting.ts

@@ -34,8 +34,10 @@ import { applyOutgoingRowCatalogDefaults } from "../outgoingRowDefaults"
 import { analyzeOutgoingDocumentLayout, DEFAULT_CONTENT_BOTTOM_MM } from "../outgoingDocumentLayout"
 import { withImages } from "../result"
 import { renderOutgoingDocumentPdf } from "../../modules/outgoing-document-pdf.service"
+import { assertOutgoingEInvoiceRequirements } from "../../modules/einvoice/outgoingZugferd.service"
 import { renderPdfPagesAsPng } from "../../utils/pdfPreview"
 import { outgoingStatusTools } from "./outgoingStatus"
+import { normalizeCashDiscountDays, normalizeCashDiscountPercent, prepareCashDiscountAllocation } from "../../modules/cash-discount"
 
 export { prepareStatementAllocationInput } from "../statementAllocations"
 
@@ -246,6 +248,8 @@ const buildOutgoingDocumentPayload = (
     for (const field of ["paymentDays"] as const) {
         if (args[field] !== undefined) payload[field] = numberArg(args, field)
     }
+    if (args.cashDiscountPercent !== undefined) payload.cashDiscountPercent = normalizeCashDiscountPercent(args.cashDiscountPercent)
+    if (args.cashDiscountDays !== undefined) payload.cashDiscountDays = normalizeCashDiscountDays(args.cashDiscountDays)
 
     if (args.type !== undefined) payload.type = documentTypeArg(args)
     if (args.address !== undefined) payload.address = optionalObjectArg(args, "address")
@@ -431,6 +435,8 @@ const buildIncomingInvoicePayload = (
     for (const field of ["state", "reference", "date", "dueDate", "description", "paymentType"] as const) {
         if (args[field] !== undefined) payload[field] = stringArg(args, field)
     }
+    if (args.cashDiscountPercent !== undefined) payload.cashDiscountPercent = normalizeCashDiscountPercent(args.cashDiscountPercent)
+    if (args.cashDiscountDueDate !== undefined) payload.cashDiscountDueDate = stringArg(args, "cashDiscountDueDate")
     if (args.vendor !== undefined) payload.vendor = numberArg(args, "vendor")
     if (args.document !== undefined) payload.document = numberArg(args, "document")
     if (args.expense !== undefined) payload.expense = args.expense === true
@@ -634,6 +640,8 @@ export const accountingTools: McpTool[] = [
                 deliveryDateEnd: { type: "string" },
                 deliveryDateType: { type: "string" },
                 paymentDays: { type: "number" },
+                cashDiscountPercent: { type: ["number", "null"], description: "Skontosatz in Prozent (0 bis 10). Wird im PDF als Skontohinweis ausgegeben." },
+                cashDiscountDays: { type: ["number", "null"], description: "Skontofrist in Tagen ab Belegdatum." },
                 payment_type: { type: "string" },
                 taxType: {
                     type: "string",
@@ -691,6 +699,8 @@ export const accountingTools: McpTool[] = [
                 deliveryDateEnd: { type: "string" },
                 deliveryDateType: { type: "string" },
                 paymentDays: { type: "number" },
+                cashDiscountPercent: { type: ["number", "null"], description: "Skontosatz in Prozent (0 bis 10). Wird im PDF als Skontohinweis ausgegeben." },
+                cashDiscountDays: { type: ["number", "null"], description: "Skontofrist in Tagen ab Belegdatum." },
                 payment_type: { type: "string" },
                 taxType: {
                     type: "string",
@@ -881,6 +891,8 @@ export const accountingTools: McpTool[] = [
                 deliveryDate: { type: "string" },
                 deliveryDateEnd: { type: "string" },
                 paymentDays: { type: "number" },
+                cashDiscountPercent: { type: ["number", "null"], description: "Skontosatz in Prozent (0 bis 10). Wird im PDF als Skontohinweis ausgegeben." },
+                cashDiscountDays: { type: ["number", "null"], description: "Skontofrist in Tagen ab Belegdatum." },
                 payment_type: { type: "string" },
                 taxType: {
                     type: "string",
@@ -908,11 +920,13 @@ export const accountingTools: McpTool[] = [
 
             if (args.rows !== undefined) args = { ...args, rows: await applyOutgoingRowCatalogDefaults(context, args.rows) }
             const payload = buildOutgoingDocumentPayload(args, context.userId, context.tenantId)
+            applyOutgoingDocumentTaxType(payload, args, existing.type, existing.taxType, existing.rows)
+            // Pflichtangaben der E-Rechnung vor der Nummernvergabe durchsetzen
+            await assertOutgoingEInvoiceRequirements(context.server, context.tenantId, { ...existing, ...payload })
             const result = await useNextNumberRangeNumber(context.server, context.tenantId, existing.type)
 
             payload.state = "Gebucht"
             payload.documentNumber = result.usedNumber
-            applyOutgoingDocumentTaxType(payload, args, existing.type, existing.taxType, existing.rows)
 
             const [updated] = await context.server.db
                 .update(createddocuments)
@@ -1200,6 +1214,8 @@ export const accountingTools: McpTool[] = [
                         reference: { type: "string" },
                         date: { type: "string" },
                         dueDate: { type: "string" },
+                        cashDiscountPercent: { type: ["number", "null"] },
+                        cashDiscountDueDate: { type: ["string", "null"] },
                         document: { type: "number" },
                         description: { type: "string" },
                         paymentType: { type: "string" },
@@ -1317,6 +1333,8 @@ export const accountingTools: McpTool[] = [
                 reference: { type: "string" },
                 date: { type: "string" },
                 dueDate: { type: "string" },
+                cashDiscountPercent: { type: ["number", "null"], description: "Skontosatz in Prozent laut Rechnung." },
+                cashDiscountDueDate: { type: ["string", "null"], description: "Letzter Tag der Skontofrist (YYYY-MM-DD)." },
                 document: { type: "number" },
                 description: { type: "string" },
                 paymentType: { type: "string" },
@@ -1350,6 +1368,8 @@ export const accountingTools: McpTool[] = [
                 reference: { type: "string" },
                 date: { type: "string" },
                 dueDate: { type: "string" },
+                cashDiscountPercent: { type: ["number", "null"], description: "Skontosatz in Prozent laut Rechnung." },
+                cashDiscountDueDate: { type: ["string", "null"], description: "Letzter Tag der Skontofrist (YYYY-MM-DD)." },
                 document: { type: "number" },
                 description: { type: "string" },
                 paymentType: { type: "string" },
@@ -1613,7 +1633,7 @@ export const accountingTools: McpTool[] = [
     {
         name: "accounting.statement_allocations.create",
         title: "Bankzuweisung erstellen",
-        description: "Erstellt eine Bankzuweisung oder manuelle Soll/Haben-Buchung. Unterstützt Ausgangs- und Eingangsbelege, Sachkonten, zusätzliche Konten, Debitoren, Kreditoren, Teilbeträge, DATEV-Steuerschlüssel und Abschreibungen.",
+        description: "Erstellt eine Bankzuweisung oder manuelle Soll/Haben-Buchung. Unterstützt Ausgangs- und Eingangsbelege, Sachkonten, zusätzliche Konten, Debitoren, Kreditoren, Teilbeträge, Skonto, DATEV-Steuerschlüssel und Abschreibungen.",
         requiredPermissions: ["accounting.statement_allocations.write"],
         inputSchema: {
             type: "object",
@@ -1621,6 +1641,7 @@ export const accountingTools: McpTool[] = [
             properties: {
                 bankstatement: { type: "number", description: "Bankumsatz-ID. Weglassen für eine manuelle Soll/Haben-Buchung." },
                 amount: { type: "number", description: "Zuweisungsbetrag mit Vorzeichen des Bankumsatzes; bei manuellen Buchungen positiv." },
+                cashDiscountAmount: { type: "number", description: "Skonto (brutto) zu einem Ausgangs- oder Eingangsbeleg, zusätzlich zum gezahlten amount. Nur mit bankstatement; das Vorzeichen wird an amount angeglichen. Wird anteilig nach Steuersätzen auf die Skontokonten verteilt." },
                 createddocument: { type: "number", description: "Ausgangsbeleg-ID." },
                 incominginvoice: { type: "number", description: "Eingangsbeleg-ID." },
                 account: { type: "number", description: "Sachkonto-ID beziehungsweise Soll-Sachkonto." },
@@ -1646,8 +1667,9 @@ export const accountingTools: McpTool[] = [
             },
         },
         async handler(context, args) {
-            const payload = prepareStatementAllocationInput(args)
+            const prepared = prepareStatementAllocationInput(args)
-            await assertStatementAllocationReferences(context, payload)
+            await assertStatementAllocationReferences(context, prepared)
+            const payload = await prepareCashDiscountAllocation(context.server.db, context.tenantId, prepared)
 
             const [created] = await context.server.db
                 .insert(statementallocations)

backend/src/mcp/tools/masterdataWrites.ts

@@ -46,14 +46,14 @@ export const masterdataWriteConfigs: Config[] = [
     makeConfig({
         resource: "customers", namespace: "customers", label: "Kunde", resultKey: "customer", table: tables.customers,
         required: ["name"], numberField: "customerNumber",
-        fieldNames: "name customerNumber infoData active notes type isCompany profiles customPaymentDays firstname lastname customSurchargePercentage salutation title nameAddition availableInPortal customPaymentType customTaxType memberrelation",
+        fieldNames: "name customerNumber infoData active notes type isCompany profiles customPaymentDays firstname lastname customSurchargePercentage salutation title nameAddition availableInPortal customPaymentType customTaxType memberrelation customCashDiscountPercent customCashDiscountDays",
         overrides: { customerNumber: textField(true), infoData: infoDataField, profiles: profilesField, memberrelation: idField },
         references: [commonProfiles, bankAccounts, { field: "memberrelation", table: tables.memberrelations }],
     }),
     makeConfig({
         resource: "vendors", namespace: "vendors", label: "Lieferant", resultKey: "vendor", table: tables.vendors,
         required: ["name"], numberField: "vendorNumber",
-        fieldNames: "name vendorNumber infoData notes hasSEPA profiles defaultPaymentMethod",
+        fieldNames: "name vendorNumber infoData notes hasSEPA profiles defaultPaymentMethod cashDiscountPercent cashDiscountDays",
         overrides: { vendorNumber: textField(true), infoData: infoDataField, profiles: profilesField },
         references: [commonProfiles, bankAccounts],
     }),

backend/src/mcp/tools/outgoingStatus.ts

@@ -41,10 +41,10 @@ function documentAmount(document: any, advanceInvoices: any[]) {
     return money(money(net) + money(tax19) + money(tax7) - advanceAmount)
 }
 
-export function outgoingDocumentStatus(document: any, paidAmount: number, cancellations: any[], advanceInvoices: any[]) {
+export function outgoingDocumentStatus(document: any, paidAmount: number, cancellations: any[], advanceInvoices: any[], cashDiscountAmount = 0) {
     const amount = documentAmount(document, advanceInvoices)
-    if (![amount, paidAmount].every(Number.isFinite)) throw new Error(`Beleg ${document.id}: Betrag kann nicht berechnet werden`)
+    if (![amount, paidAmount, cashDiscountAmount].every(Number.isFinite)) throw new Error(`Beleg ${document.id}: Betrag kann nicht berechnet werden`)
-    const openAmount = money(amount - paidAmount)
+    const openAmount = money(amount - paidAmount - cashDiscountAmount)
     const cancelled = cancellations.length > 0
     const applicable = document.state === "Gebucht" && ["invoices", "advanceInvoices"].includes(document.type) && !cancelled
     // Signed invoices and refunds use the same payment-direction comparison.
@@ -55,7 +55,7 @@ export function outgoingDocumentStatus(document: any, paidAmount: number, cancel
         id: document.id, type: document.type, documentNumber: document.documentNumber, documentDate: document.documentDate,
         state: document.state, customer: document.customer, project: document.project,
         cancelled, cancellationDocuments: cancellations.map(({ id, documentNumber }) => ({ id, documentNumber })),
-        paymentStatus, amount, paidAmount: money(paidAmount), openAmount,
+        paymentStatus, amount, paidAmount: money(paidAmount), cashDiscountAmount: money(cashDiscountAmount), openAmount,
     }
 }
 
@@ -65,7 +65,7 @@ async function statusesFor(context: McpContext, documents: Array<typeof createdd
     const advanceIds = [...new Set(documents.flatMap(document => Array.isArray(document.usedAdvanceInvoices)
         ? document.usedAdvanceInvoices.filter(id => typeof id === "number" && Number.isSafeInteger(id) && id > 0) as number[] : []))]
     const [allocations, cancellations, advances] = await Promise.all([
-        context.server.db.select({ createddocument: statementallocations.createddocument, amount: statementallocations.amount }).from(statementallocations)
+        context.server.db.select({ createddocument: statementallocations.createddocument, amount: statementallocations.amount, cashDiscountAmount: statementallocations.cashDiscountAmount }).from(statementallocations)
             .where(and(eq(statementallocations.tenant, context.tenantId), eq(statementallocations.archived, false), inArray(statementallocations.createddocument, ids))),
         context.server.db.select({ id: createddocuments.id, createddocument: createddocuments.createddocument, documentNumber: createddocuments.documentNumber }).from(createddocuments)
             .where(and(eq(createddocuments.tenant, context.tenantId), eq(createddocuments.archived, false), eq(createddocuments.type, "cancellationInvoices"),
@@ -73,15 +73,19 @@ async function statusesFor(context: McpContext, documents: Array<typeof createdd
         advanceIds.length ? context.server.db.select().from(createddocuments)
             .where(and(eq(createddocuments.tenant, context.tenantId), eq(createddocuments.archived, false), inArray(createddocuments.id, advanceIds))) : [],
     ])
-    return documents.map(document => outgoingDocumentStatus(document,
+    return documents.map(document => {
-        allocations.filter(allocation => allocation.createddocument === document.id).reduce((sum, allocation) => sum + Number(allocation.amount), 0),
+        const documentAllocations = allocations.filter(allocation => allocation.createddocument === document.id)
-        cancellations.filter(cancellation => cancellation.createddocument === document.id), advances))
+        return outgoingDocumentStatus(document,
+            documentAllocations.reduce((sum, allocation) => sum + Number(allocation.amount), 0),
+            cancellations.filter(cancellation => cancellation.createddocument === document.id), advances,
+            documentAllocations.reduce((sum, allocation) => sum + Number(allocation.cashDiscountAmount || 0), 0))
+    })
 }
 
 export const outgoingStatusTools: McpTool[] = [
     {
         name: "accounting.outgoing_documents.status.get", title: "Ausgangsbelegstatus laden",
-        description: "Lädt Buchungs-, Zahlungs- und Stornostatus mit Gesamtbetrag, zugeordneten Zahlungen und offenem Betrag. Zahlungsstatus gilt für gebuchte, nicht stornierte Rechnungen und Abschlagsrechnungen; sonst null. Ändert keine Belege oder Buchungen.",
+        description: "Lädt Buchungs-, Zahlungs- und Stornostatus mit Gesamtbetrag, zugeordneten Zahlungen, gebuchtem Skonto und offenem Betrag. Zahlungsstatus gilt für gebuchte, nicht stornierte Rechnungen und Abschlagsrechnungen; sonst null. Ändert keine Belege oder Buchungen.",
         requiredPermissions: ["accounting.outgoing_documents.read"],
         inputSchema: { ...objectField({ id: idField }).schema, required: ["id"] },
         async handler(context, args) {

backend/src/modules/cash-discount.ts

@@ -0,0 +1,378 @@
+import { and, eq, inArray } from "drizzle-orm"
+import { createddocuments, incominginvoices, statementallocations, tenants } from "../../db/schema"
+
+// Skonto wird an der Zahlungszuordnung gespeichert. amount bleibt der tatsächlich gezahlte Betrag,
+// cashDiscountAmount trägt dasselbe Vorzeichen und schließt zusammen mit amount den Beleg aus.
+
+export type CashDiscountRate = "19" | "7" | "0"
+export type CashDiscountSide = "received" | "granted"
+export type CashDiscountAccountConfig = Record<CashDiscountSide, Record<CashDiscountRate, string>>
+export type CashDiscountSplitItem = { rate: number, account: string, gross: number, net: number, tax: number }
+
+export const CASH_DISCOUNT_RATES: CashDiscountRate[] = ["19", "7", "0"]
+
+// SKR03: Erhaltene Skonti (Eingangsbelege) und gewährte Skonti (Ausgangsbelege), jeweils Automatikkonten.
+export const DEFAULT_CASH_DISCOUNT_ACCOUNTS: CashDiscountAccountConfig = {
+    received: { "19": "3736", "7": "3731", "0": "3730" },
+    granted: { "19": "8736", "7": "8731", "0": "8730" },
+}
+
+// Weicht der Skonto um mehr als diesen Anteil vom Beleg ab, liegt sehr wahrscheinlich ein Eingabefehler vor.
+export const MAX_CASH_DISCOUNT_SHARE = 0.1
+
+const invalidInput = (message: string) => Object.assign(new Error(message), { statusCode: 400 })
+const money = (value: number) => Number(value.toFixed(2))
+const sameSign = (value: number, sign: number) => sign === 0 || Math.sign(value) === 0 || Math.sign(value) === sign
+
+export function resolveCashDiscountAccounts(config: any): CashDiscountAccountConfig {
+    const result = {
+        received: { ...DEFAULT_CASH_DISCOUNT_ACCOUNTS.received },
+        granted: { ...DEFAULT_CASH_DISCOUNT_ACCOUNTS.granted },
+    }
+    for (const side of ["received", "granted"] as const) {
+        for (const rate of CASH_DISCOUNT_RATES) {
+            const value = config?.[side]?.[rate]
+            if (typeof value === "string" && value.trim()) result[side][rate] = value.trim()
+            else if (typeof value === "number" && Number.isFinite(value)) result[side][rate] = String(value)
+        }
+    }
+    return result
+}
+
+// Validiert die Einstellung aus den Firmeneinstellungen. Leere Felder fallen auf SKR03 zurück.
+export function normalizeCashDiscountAccountsInput(input: any): Partial<CashDiscountAccountConfig> {
+    if (!input || typeof input !== "object" || Array.isArray(input)) {
+        throw invalidInput("Die Skontokonten müssen als Objekt übergeben werden.")
+    }
+    const result: Partial<CashDiscountAccountConfig> = {}
+    for (const side of ["received", "granted"] as const) {
+        const entries: Partial<Record<CashDiscountRate, string>> = {}
+        for (const rate of CASH_DISCOUNT_RATES) {
+            const raw = input?.[side]?.[rate]
+            if (raw === undefined || raw === null || String(raw).trim() === "") continue
+            const value = String(raw).trim()
+            if (!/^\d{4,9}$/.test(value)) {
+                throw invalidInput(`Das Skontokonto ${value} muss aus 4 bis 9 Ziffern bestehen.`)
+            }
+            entries[rate] = value
+        }
+        if (Object.keys(entries).length) result[side] = entries as Record<CashDiscountRate, string>
+    }
+    return result
+}
+
+export function settledAllocationAmount(allocation: { amount?: any, cashDiscountAmount?: any }) {
+    return Number(allocation?.amount || 0) + Number(allocation?.cashDiscountAmount || 0)
+}
+
+type GrossByRate = Record<CashDiscountRate, number>
+const emptyGross = (): GrossByRate => ({ "19": 0, "7": 0, "0": 0 })
+
+// Bruttobeträge eines Eingangsbelegs je Steuersatz. Vorzeichen: Ausgaben negativ (wie die Bankzuordnung).
+export function getIncomingInvoiceGrossByRate(invoice: any): GrossByRate {
+    const gross = emptyGross()
+    const accounts = Array.isArray(invoice?.accounts) ? invoice.accounts : []
+    for (const account of accounts) {
+        const taxType = account?.taxType === null || account?.taxType === undefined ? "null" : String(account.taxType)
+        const amount = Number(account?.amountNet || 0) + Number(account?.amountTax || 0)
+        if (!Number.isFinite(amount)) throw invalidInput("Der Eingangsbeleg enthält ungültige Beträge.")
+        if (amount === 0) continue
+        if (taxType === "19" || taxType === "7") gross[taxType] += amount
+        else if (taxType === "null" || taxType === "" || taxType === "0") gross["0"] += amount
+        else {
+            throw invalidInput("Skonto auf Belege mit innergemeinschaftlichem Erwerb oder §13b UStG bitte manuell buchen.")
+        }
+    }
+
+    const override = invoice?.taxAmountOverride
+    if (override !== null && override !== undefined && override !== "") {
+        const calculatedTax = accounts.reduce((sum: number, account: any) => sum + Number(account?.amountTax || 0), 0)
+        const correction = Number(override) - calculatedTax
+        if (Number.isFinite(correction) && Math.abs(correction) >= 0.005) {
+            if (gross["19"] !== 0) gross["19"] += correction
+            else if (gross["7"] !== 0) gross["7"] += correction
+        }
+    }
+
+    const sign = invoice?.expense === false ? 1 : -1
+    return {
+        "19": money(gross["19"] * sign),
+        "7": money(gross["7"] * sign),
+        "0": money(gross["0"] * sign),
+    }
+}
+
+const rowsGrossByRate = (document: any, taxFree: boolean): GrossByRate => {
+    const net = emptyGross()
+    for (const row of Array.isArray(document?.rows) ? document.rows : []) {
+        if (!row || ["pagebreak", "title", "text"].includes(row.mode)) continue
+        const rowNet = Number((Number(row.quantity || 0) * Number(row.price || 0) * (1 - Number(row.discountPercent || 0) / 100)).toFixed(3))
+        if (!Number.isFinite(rowNet)) throw invalidInput(`Beleg ${document.id}: ungültiger Positionsbetrag`)
+        const taxPercent = Number(row.taxPercent)
+        if (!taxFree && taxPercent === 19) net["19"] += rowNet
+        else if (!taxFree && taxPercent === 7) net["7"] += rowNet
+        else net["0"] += rowNet
+    }
+    return {
+        "19": money(money(net["19"]) + money(net["19"] * 0.19)),
+        "7": money(money(net["7"]) + money(net["7"] * 0.07)),
+        "0": money(net["0"]),
+    }
+}
+
+const createdDocumentAmounts = (document: any, advanceInvoices: any[]) => {
+    if (document?.taxType === "13b UStG") {
+        throw invalidInput("Skonto auf Ausgangsbelege nach §13b UStG bitte manuell buchen.")
+    }
+    const taxFree = ["19 UStG", "12.3 UStG"].includes(String(document?.taxType || ""))
+    const gross = rowsGrossByRate(document, taxFree)
+    const advances = emptyGross()
+    for (const id of Array.isArray(document?.usedAdvanceInvoices) ? document.usedAdvanceInvoices : []) {
+        const row = advanceInvoices.find((invoice) => invoice.id === id)?.rows?.find((row: any) => row?.advanceInvoiceData)
+        if (!row) continue
+        const rate = String(Number(row.taxPercent)) as CashDiscountRate
+        const amount = Number(row.price) * ((100 + Number(row.taxPercent || 0)) / 100)
+        advances[!taxFree && (rate === "19" || rate === "7") ? rate : "0"] += amount
+    }
+    return { gross, advances }
+}
+
+// Bruttobeträge eines Ausgangsbelegs je Steuersatz. Bei Schlussrechnungen werden die Abschläge mit ihren
+// ursprünglich berechneten Beträgen abgezogen, damit sich der Skonto auf die Restforderung verteilt.
+export function getCreatedDocumentGrossByRate(document: any, advanceInvoices: any[] = []): GrossByRate {
+    const { gross, advances } = createdDocumentAmounts(document, advanceInvoices)
+    const total = gross["19"] + gross["7"] + gross["0"]
+    const sign = Math.sign(total) || 1
+    const remaining = emptyGross()
+    for (const rate of CASH_DISCOUNT_RATES) {
+        const value = money(gross[rate] - advances[rate])
+        remaining[rate] = sameSign(value, sign) ? value : 0
+    }
+    return remaining["19"] || remaining["7"] || remaining["0"] ? remaining : gross
+}
+
+// Offene Gesamtforderung des Ausgangsbelegs: Bruttobetrag abzüglich der berechneten Abschläge.
+export function getCreatedDocumentGrossTotal(document: any, advanceInvoices: any[] = []) {
+    const { gross, advances } = createdDocumentAmounts(document, advanceInvoices)
+    return money(gross["19"] + gross["7"] + gross["0"] - advances["19"] - advances["7"] - advances["0"])
+}
+
+// Verteilt den Skonto anteilig auf die Steuersätze; Rundungsdifferenzen gehen an den größten Anteil.
+export function splitCashDiscount(amount: number, grossByRate: GrossByRate, accounts: Record<CashDiscountRate, string>): CashDiscountSplitItem[] {
+    const discount = money(amount)
+    if (!discount) return []
+    const weights = CASH_DISCOUNT_RATES
+        .map((rate) => ({ rate, weight: Math.abs(Number(grossByRate[rate] || 0)) }))
+        .filter((item) => item.weight > 0)
+    if (!weights.length) weights.push({ rate: "0", weight: 1 })
+
+    const totalWeight = weights.reduce((sum, item) => sum + item.weight, 0)
+    const items = weights.map((item) => ({ rate: item.rate, gross: money(discount * item.weight / totalWeight) }))
+    const difference = money(discount - items.reduce((sum, item) => sum + item.gross, 0))
+    if (difference) {
+        const largest = items.reduce((max, item) => Math.abs(item.gross) > Math.abs(max.gross) ? item : max, items[0])
+        largest.gross = money(largest.gross + difference)
+    }
+
+    return items.filter((item) => item.gross !== 0).map((item) => {
+        const rate = Number(item.rate)
+        const net = money(item.gross / (1 + rate / 100))
+        return { rate, account: accounts[item.rate], gross: item.gross, net, tax: money(item.gross - net) }
+    })
+}
+
+// Bereitet Skonto für eine neue Bankzuordnung vor: Vorzeichen, Plausibilität und Steueraufteilung.
+export async function prepareCashDiscountAllocation(db: any, tenantId: number, payload: Record<string, any>) {
+    const requested = Number(payload.cashDiscountAmount || 0)
+    if (!Number.isFinite(requested)) throw invalidInput("Der Skontobetrag muss eine gültige Zahl sein.")
+    if (Math.abs(requested) < 0.005) {
+        return { ...payload, cashDiscountAmount: null, cashDiscountSplit: null }
+    }
+
+    const amount = Number(payload.amount || 0)
+    if (!payload.bankstatement) throw invalidInput("Skonto kann nur zusammen mit einer Bankzahlung gebucht werden.")
+    const hasDocument = Boolean(payload.createddocument)
+    const hasInvoice = Boolean(payload.incominginvoice)
+    if (hasDocument === hasInvoice) {
+        throw invalidInput("Skonto ist nur bei der Zuordnung genau eines Ausgangs- oder Eingangsbelegs möglich.")
+    }
+    if (!amount) throw invalidInput("Für Skonto muss ein Zahlbetrag zugeordnet werden.")
+
+    const discount = money(Math.sign(amount) * Math.abs(requested))
+    const [tenant] = await db.select({ cashDiscountAccounts: tenants.cashDiscountAccounts })
+        .from(tenants).where(eq(tenants.id, tenantId)).limit(1)
+    const accounts = resolveCashDiscountAccounts(tenant?.cashDiscountAccounts)
+
+    let grossByRate: GrossByRate
+    let total: number
+    let existing: any[]
+
+    if (hasDocument) {
+        const documentId = Number(payload.createddocument)
+        const [document] = await db.select().from(createddocuments).where(and(
+            eq(createddocuments.id, documentId),
+            eq(createddocuments.tenant, tenantId),
+        )).limit(1)
+        if (!document || document.archived) throw invalidInput("Der Ausgangsbeleg wurde nicht gefunden.")
+        if (document.state !== "Gebucht") throw invalidInput("Skonto ist nur auf gebuchte Ausgangsbelege möglich.")
+        const advanceIds = (Array.isArray(document.usedAdvanceInvoices) ? document.usedAdvanceInvoices : [])
+            .filter((id: any) => Number.isSafeInteger(id) && id > 0)
+        const advanceInvoices = advanceIds.length
+            ? await db.select().from(createddocuments).where(and(
+                eq(createddocuments.tenant, tenantId),
+                inArray(createddocuments.id, advanceIds),
+            ))
+            : []
+        grossByRate = getCreatedDocumentGrossByRate(document, advanceInvoices)
+        total = getCreatedDocumentGrossTotal(document, advanceInvoices)
+        existing = await db.select({ amount: statementallocations.amount, cashDiscountAmount: statementallocations.cashDiscountAmount })
+            .from(statementallocations).where(and(
+                eq(statementallocations.createddocument, documentId),
+                eq(statementallocations.tenant, tenantId),
+                eq(statementallocations.archived, false),
+            ))
+    } else {
+        const invoiceId = Number(payload.incominginvoice)
+        const [invoice] = await db.select().from(incominginvoices).where(and(
+            eq(incominginvoices.id, invoiceId),
+            eq(incominginvoices.tenant, tenantId),
+        )).limit(1)
+        if (!invoice || invoice.archived) throw invalidInput("Der Eingangsbeleg wurde nicht gefunden.")
+        if (invoice.state !== "Gebucht") throw invalidInput("Skonto ist nur auf gebuchte Eingangsbelege möglich.")
+        grossByRate = getIncomingInvoiceGrossByRate(invoice)
+        total = money(grossByRate["19"] + grossByRate["7"] + grossByRate["0"])
+        existing = await db.select({ amount: statementallocations.amount, cashDiscountAmount: statementallocations.cashDiscountAmount })
+            .from(statementallocations).where(and(
+                eq(statementallocations.incominginvoice, invoiceId),
+                eq(statementallocations.tenant, tenantId),
+                eq(statementallocations.archived, false),
+            ))
+    }
+
+    validateCashDiscount({ amount, discount, total, settled: existing.reduce((sum, item) => sum + settledAllocationAmount(item), 0) })
+
+    const side: CashDiscountSide = hasDocument ? "granted" : "received"
+    return {
+        ...payload,
+        cashDiscountAmount: discount,
+        cashDiscountSplit: splitCashDiscount(discount, grossByRate, accounts[side]),
+    }
+}
+
+export function validateCashDiscount({ amount, discount, total, settled }: { amount: number, discount: number, total: number, settled: number }) {
+    if (!total) throw invalidInput("Der Beleg hat keinen Betrag, auf den Skonto gebucht werden kann.")
+    if (Math.sign(amount) !== Math.sign(total)) {
+        throw invalidInput("Skonto ist nur bei Zahlungen in Richtung des Belegs möglich.")
+    }
+    const open = money(total - settled)
+    if (Math.abs(amount + discount) > Math.abs(open) + 0.02 || Math.sign(open) !== Math.sign(total)) {
+        throw invalidInput(`Zahlung und Skonto übersteigen den offenen Betrag von ${Math.abs(open).toFixed(2).replace(".", ",")} €.`)
+    }
+    if (Math.abs(discount) > Math.abs(total) * MAX_CASH_DISCOUNT_SHARE + 0.005) {
+        throw invalidInput(`Der Skonto ist höher als ${MAX_CASH_DISCOUNT_SHARE * 100} % des Belegbetrags. Bitte Betrag prüfen.`)
+    }
+}
+
+// ---------------------------------------------------------------------------
+// Skonto-Bedingungen auf Belegen
+// ---------------------------------------------------------------------------
+
+export type CashDiscountTerms = {
+    percent: number
+    days: number | null
+    dueDate: string | null
+    discount: number
+    payable: number
+}
+
+const formatEuro = (value: number) => new Intl.NumberFormat("de-DE", { style: "currency", currency: "EUR" }).format(value)
+const formatGermanDate = (value: string) => {
+    const [year, month, day] = value.split("-")
+    return `${day}.${month}.${year}`
+}
+
+const addDays = (date: string, days: number) => {
+    const parsed = new Date(`${String(date).slice(0, 10)}T00:00:00Z`)
+    if (Number.isNaN(parsed.getTime())) return null
+    parsed.setUTCDate(parsed.getUTCDate() + days)
+    return parsed.toISOString().slice(0, 10)
+}
+
+export function normalizeCashDiscountPercent(value: unknown) {
+    if (value === null || value === undefined || value === "") return null
+    const percent = Number(String(value).replace(",", "."))
+    if (!Number.isFinite(percent) || percent < 0 || percent > 10) {
+        throw invalidInput("Der Skontosatz muss zwischen 0 und 10 % liegen.")
+    }
+    return percent === 0 ? null : Number(percent.toFixed(2))
+}
+
+export function normalizeCashDiscountDays(value: unknown) {
+    if (value === null || value === undefined || value === "") return null
+    const days = Number(value)
+    if (!Number.isInteger(days) || days < 0 || days > 365) {
+        throw invalidInput("Die Skontofrist muss zwischen 0 und 365 Tagen liegen.")
+    }
+    return days
+}
+
+// Berechnet Frist, Skonto und Zahlbetrag aus Satz, Tagen und Belegdatum.
+export function buildCashDiscountTerms({ percent, days, documentDate, dueDate, amount }: {
+    percent: unknown, days?: unknown, documentDate?: string | null, dueDate?: string | null, amount: number
+}): CashDiscountTerms | null {
+    const normalizedPercent = Number(percent)
+    if (!Number.isFinite(normalizedPercent) || normalizedPercent <= 0 || !Number.isFinite(amount) || !amount) return null
+    const normalizedDays = days === null || days === undefined || days === "" ? null : Number(days)
+    const computedDueDate = dueDate
+        ? String(dueDate).slice(0, 10)
+        : documentDate && normalizedDays !== null && Number.isFinite(normalizedDays) ? addDays(documentDate, normalizedDays) : null
+    const discount = money(amount * normalizedPercent / 100)
+    return {
+        percent: normalizedPercent,
+        days: normalizedDays !== null && Number.isFinite(normalizedDays) ? normalizedDays : null,
+        dueDate: computedDueDate,
+        discount,
+        payable: money(amount - discount),
+    }
+}
+
+export function formatCashDiscountText(terms: CashDiscountTerms | null) {
+    if (!terms) return ""
+    const percent = String(terms.percent).replace(".", ",")
+    const deadline = terms.dueDate
+        ? `bis zum ${formatGermanDate(terms.dueDate)}`
+        : terms.days !== null ? `innerhalb von ${terms.days} Tagen` : "bei sofortiger Zahlung"
+    return `Bei Zahlung ${deadline} gewähren wir ${percent} % Skonto (${formatEuro(Math.abs(terms.discount))}), Zahlbetrag ${formatEuro(Math.abs(terms.payable))}.`
+}
+
+// Kontextvariablen für Textvorlagen; der Satz wird automatisch ergänzt, wenn die Vorlage keine Skontovariable nutzt.
+export function getCashDiscountTemplateContext(terms: CashDiscountTerms | null) {
+    if (!terms) return {}
+    return {
+        skonto_prozent: String(terms.percent).replace(".", ","),
+        skonto_tage: terms.days,
+        skonto_datum: terms.dueDate ? formatGermanDate(terms.dueDate) : null,
+        skonto_betrag: formatEuro(Math.abs(terms.discount)),
+        zahlbetrag_mit_skonto: formatEuro(Math.abs(terms.payable)),
+        skonto_hinweis: formatCashDiscountText(terms),
+    }
+}
+
+export function appendCashDiscountText(renderedText: string, template: string | null | undefined, terms: CashDiscountTerms | null) {
+    if (!terms || /skonto_/i.test(String(template || ""))) return renderedText
+    const sentence = formatCashDiscountText(terms)
+    return renderedText ? `${sentence}\n\n${renderedText}` : sentence
+}
+
+// Liest Skontobedingungen aus E-Rechnungen: XRechnung "#SKONTO#TAGE=14#PROZENT=2.00#" im Zahlungsbedingungstext.
+export function parseCashDiscountPaymentTerms(text: unknown): { percent: number, days: number } | null {
+    const source = String(text || "")
+    const matches = [...source.matchAll(/#SKONTO#([^\n]*?)#(?:\s|$)/gi)]
+    for (const match of matches) {
+        const segment = match[1]
+        const days = Number(segment.match(/TAGE=(\d+)/i)?.[1])
+        const percent = Number(segment.match(/PROZENT=(\d+(?:[.,]\d+)?)/i)?.[1]?.replace(",", "."))
+        if (Number.isInteger(days) && Number.isFinite(percent) && percent > 0) return { percent, days }
+    }
+    return null
+}

backend/src/modules/cron/prepareIncomingInvoices.ts

@@ -31,7 +31,7 @@ const formatInvoiceItemDescription = (item: any) => {
     return parts.join(" - ")
 }
 
-const mapGptDataToIncomingInvoice = (data: any, tenantId: number) => {
+export const mapGptDataToIncomingInvoice = (data: any, tenantId: number) => {
     const itemInfo: any = {
         tenant: tenantId,
         state: "Vorbereitet",
@@ -43,6 +43,17 @@ const mapGptDataToIncomingInvoice = (data: any, tenantId: number) => {
     if (data.issuer?.id) itemInfo.vendor = data.issuer.id
     if (data.invoice_duedate && dayjs(data.invoice_duedate).isValid()) itemInfo.dueDate = dayjs(data.invoice_duedate).toISOString()
 
+    // Skonto nur übernehmen, wenn die Rechnung ihn ausdrücklich nennt (siehe Prompt).
+    const cashDiscountPercent = Number(data.cash_discount_percent)
+    if (Number.isFinite(cashDiscountPercent) && cashDiscountPercent > 0 && cashDiscountPercent <= 10) {
+        itemInfo.cashDiscountPercent = Number(cashDiscountPercent.toFixed(2))
+        if (data.cash_discount_due_date && dayjs(data.cash_discount_due_date).isValid()) {
+            itemInfo.cashDiscountDueDate = dayjs(data.cash_discount_due_date).format("YYYY-MM-DD")
+        } else if (Number.isInteger(data.cash_discount_days) && data.invoice_date && dayjs(data.invoice_date).isValid()) {
+            itemInfo.cashDiscountDueDate = dayjs(data.invoice_date).add(data.cash_discount_days, "day").format("YYYY-MM-DD")
+        }
+    }
+
     const mapPayment: Record<string, string> = {
         "Direct Debit": "Einzug",
         "Transfer": "Überweisung",

backend/src/modules/einvoice/buildZugferdInvoice.ts

@@ -0,0 +1,374 @@
+import dayjs from "dayjs"
+import { buildCashDiscountTerms } from "../cash-discount"
+
+/**
+ * Erzeugt das strukturierte CII-XML (ZUGFeRD 2.x / Factur-X, Profil EN 16931) für Ausgangsrechnungen.
+ * Grundlage ist der gespeicherte Beleg, nicht die formatierten PDF-Daten, damit alle Beträge numerisch bleiben.
+ */
+
+export const ZUGFERD_DOCUMENT_TYPES = ["invoices", "advanceInvoices", "cancellationInvoices", "serialInvoices"]
+export const ZUGFERD_GUIDELINE_ID = "urn:cen.eu:en16931:2017"
+export const ZUGFERD_FILENAME = "factur-x.xml"
+
+export type ZugferdInvoiceContext = {
+    tenant: any
+    customer: any
+    contact?: any
+    contactPerson?: any
+    project?: any
+    contract?: any
+    linkedDocument?: any
+    sepaMandate?: any
+    units: any[]
+    products: any[]
+    services: any[]
+    bankAccounts: any[]
+    advanceInvoices: any[]
+}
+
+export type ZugferdInvoiceResult = {
+    xml: string
+    issues: ZugferdIssue[]
+    totals: { lineNet: number, tax: number, gross: number, prepaid: number, payable: number }
+}
+
+type TaxCategory = "S" | "Z" | "E" | "AE"
+type TaxGroup = { category: TaxCategory, rate: number, basis: number, exemptionReason?: string, exemptionReasonCode?: string }
+
+const round = (value: number, digits = 2) => {
+    const factor = 10 ** digits
+    const rounded = Math.round((value + Number.EPSILON * Math.sign(value)) * factor) / factor
+    return Object.is(rounded, -0) ? 0 : rounded
+}
+const amount = (value: number) => round(value).toFixed(2)
+const decimal = (value: number, maxDigits = 4) => String(round(value, maxDigits))
+
+const escapeXml = (value: unknown) => String(value ?? "")
+    .replace(/[\u0000-\u0008\u000B\u000C\u000E-\u001F]/g, "")
+    .replace(/&/g, "&")
+    .replace(/</g, "&lt;")
+    .replace(/>/g, "&gt;")
+    .replace(/"/g, "&quot;")
+
+const text = (value: unknown) => String(value ?? "").trim()
+const el = (name: string, value: unknown, attributes = "") => {
+    const content = text(value)
+    return content ? `<${name}${attributes}>${escapeXml(content)}</${name}>` : ""
+}
+const date102 = (value: unknown) => {
+    if (!value) return ""
+    const parsed = dayjs(value as any)
+    return parsed.isValid() ? parsed.format("YYYYMMDD") : ""
+}
+const dateElement = (name: string, value: unknown) => {
+    const formatted = date102(value)
+    return formatted ? `<${name}><udt:DateTimeString format="102">${formatted}</udt:DateTimeString></${name}>` : ""
+}
+
+const countryCodes: Record<string, string> = {
+    deutschland: "DE", germany: "DE", österreich: "AT", oesterreich: "AT", austria: "AT", schweiz: "CH", switzerland: "CH",
+    liechtenstein: "LI", frankreich: "FR", france: "FR", italien: "IT", italy: "IT", niederlande: "NL", netherlands: "NL",
+    belgien: "BE", belgium: "BE", luxemburg: "LU", luxembourg: "LU", dänemark: "DK", daenemark: "DK", denmark: "DK",
+    polen: "PL", poland: "PL", tschechien: "CZ", "tschechische republik": "CZ", spanien: "ES", spain: "ES",
+    portugal: "PT", schweden: "SE", sweden: "SE", norwegen: "NO", norway: "NO", finnland: "FI", finland: "FI",
+    ungarn: "HU", hungary: "HU", slowakei: "SK", slowenien: "SI", kroatien: "HR", rumänien: "RO", bulgarien: "BG",
+    griechenland: "GR", irland: "IE", ireland: "IE", "vereinigtes königreich": "GB", großbritannien: "GB", england: "GB",
+    "united kingdom": "GB", usa: "US", "vereinigte staaten": "US", estland: "EE", lettland: "LV", litauen: "LT",
+    malta: "MT", zypern: "CY", türkei: "TR",
+}
+
+export function countryCode(value: unknown) {
+    const normalized = text(value).toLocaleLowerCase("de")
+    if (!normalized) return "DE"
+    if (/^[a-z]{2}$/.test(normalized)) return normalized.toUpperCase()
+    return countryCodes[normalized] || "DE"
+}
+
+// UN/ECE Recommendation 20/21, abgebildet über das Kürzel der FEDEO-Einheit.
+const unitCodes: Record<string, string> = {
+    stk: "H87", stück: "H87", m: "MTR", meter: "MTR", km: "KMT", kilometer: "KMT", tag: "DAY", tage: "DAY",
+    std: "HUR", h: "HUR", stunde: "HUR", stunden: "HUR", min: "MIN", minute: "MIN", minuten: "MIN",
+    pausch: "LS", pauschal: "LS", psch: "LS", mon: "MON", monat: "MON", jahr: "ANN", woche: "WEE",
+    pck: "PK", packung: "PK", pers: "IE", person: "IE", l: "LTR", liter: "LTR", ha: "HAR", hektar: "HAR",
+    "m²": "MTK", m2: "MTK", qm: "MTK", quadratmeter: "MTK", "m³": "MTQ", m3: "MTQ", kubikmeter: "MTQ",
+    kg: "KGM", kilogramm: "KGM", g: "GRM", t: "TNE", tonne: "TNE", gb: "E34", gigabyte: "E34", kwp: "KWT", kwh: "KWH",
+}
+
+export function unitCode(unit: any) {
+    for (const candidate of [unit?.short, unit?.single, unit?.name]) {
+        const code = unitCodes[text(candidate).toLocaleLowerCase("de")]
+        if (code) return code
+    }
+    return "C62"
+}
+
+const isItemRow = (row: any) => !["pagebreak", "title", "text"].includes(row?.mode) && !row?.optional && !row?.alternative
+
+function taxGroupFor(taxType: string | null | undefined, rate: number): Omit<TaxGroup, "basis"> {
+    if (taxType === "13b UStG") return {
+        category: "AE", rate: 0, exemptionReasonCode: "VATEX-EU-AE",
+        exemptionReason: "Steuerschuldnerschaft des Leistungsempfängers gemäß § 13b UStG",
+    }
+    if (taxType === "19 UStG") return {
+        category: "E", rate: 0,
+        exemptionReason: "Kein Ausweis von Umsatzsteuer, da Kleinunternehmer gemäß § 19 UStG",
+    }
+    if (taxType === "12.3 UStG") return { category: "Z", rate: 0 }
+    return rate > 0 ? { category: "S", rate } : { category: "Z", rate: 0 }
+}
+
+function advanceInvoiceGross(invoice: any) {
+    const row = (invoice?.rows || []).find((item: any) => item.advanceInvoiceData)
+    return row ? Number(row.price) * ((100 + Number(row.taxPercent)) / 100) : 0
+}
+
+function typeCode(type: string) {
+    if (type === "advanceInvoices") return "386"
+    if (type === "cancellationInvoices") return "381"
+    return "380"
+}
+
+function partyAddress(address: { zip?: unknown, street?: unknown, special?: unknown, city?: unknown, country?: unknown }) {
+    return `<ram:PostalTradeAddress>${el("ram:PostcodeCode", address.zip)}${el("ram:LineOne", address.street)}${el("ram:LineTwo", address.special)}${el("ram:CityName", address.city)}<ram:CountryID>${countryCode(address.country)}</ram:CountryID></ram:PostalTradeAddress>`
+}
+
+function tradeContact(name: unknown, phone?: unknown, email?: unknown) {
+    if (!text(name) && !text(phone) && !text(email)) return ""
+    return `<ram:DefinedTradeContact>${el("ram:PersonName", name)}${text(phone) ? `<ram:TelephoneUniversalCommunication>${el("ram:CompleteNumber", phone)}</ram:TelephoneUniversalCommunication>` : ""}${text(email) ? `<ram:EmailURIUniversalCommunication>${el("ram:URIID", email)}</ram:EmailURIUniversalCommunication>` : ""}</ram:DefinedTradeContact>`
+}
+
+function taxRegistrations(vatId: unknown, taxNumber?: unknown) {
+    return [
+        text(vatId) ? `<ram:SpecifiedTaxRegistration><ram:ID schemeID="VA">${escapeXml(text(vatId).replace(/\s+/g, ""))}</ram:ID></ram:SpecifiedTaxRegistration>` : "",
+        text(taxNumber) ? `<ram:SpecifiedTaxRegistration><ram:ID schemeID="FC">${escapeXml(text(taxNumber))}</ram:ID></ram:SpecifiedTaxRegistration>` : "",
+    ].join("")
+}
+
+export type ZugferdIssue = { message: string, type: "breaking" | "info" }
+
+const sellerIban = (context: ZugferdInvoiceContext) => {
+    const businessInfo = context.tenant?.businessInfo || {}
+    const account = context.bankAccounts.find((item) => !item.archived && !item.expired && item.iban)
+    return text(businessInfo.iban || account?.iban).replace(/\s+/g, "")
+}
+
+/**
+ * Pflichtangaben einer E-Rechnung (EN 16931 / § 14 UStG). "breaking" verhindert das Fertigstellen,
+ * "info" ist ein Hinweis. requireNumber prüft zusätzlich Nummer und Datum, die erst beim Fertigstellen entstehen.
+ */
+export function checkZugferdRequirements(document: any, context: ZugferdInvoiceContext, options: { requireNumber?: boolean } = {}): ZugferdIssue[] {
+    const issues: ZugferdIssue[] = []
+    const breaking = (message: string) => issues.push({ message: `E-Rechnung: ${message}`, type: "breaking" })
+    const info = (message: string) => issues.push({ message: `E-Rechnung: ${message}`, type: "info" })
+    const businessInfo = context.tenant?.businessInfo || {}
+    const customer = context.customer || {}
+    const customerInfo = customer.infoData || {}
+    const address = document.address || {}
+
+    if (options.requireNumber && !text(document.documentNumber)) breaking("Die Rechnungsnummer fehlt")
+    if (options.requireNumber && !date102(document.documentDate)) breaking("Das Rechnungsdatum fehlt")
+    if (!text(businessInfo.name || context.tenant?.name)) breaking("Der Firmenname fehlt in den Firmendaten (Einstellungen > Firmendaten)")
+    if (!text(businessInfo.street) || !text(businessInfo.zip) || !text(businessInfo.city)) breaking("Die Firmenanschrift ist in den Firmendaten unvollständig (Straße, PLZ, Ort)")
+    if (!text(businessInfo.vatId) && !text(businessInfo.taxNumber)) breaking("In den Firmendaten ist weder eine USt-IdNr. noch eine Steuernummer hinterlegt")
+    if (document.customer && !text(customer.name)) breaking("Der Kunde hat keinen Namen")
+    if (document.customer && (!text(address.street ?? customerInfo.street) || !text(address.zip ?? customerInfo.zip) || !text(address.city ?? customerInfo.city))) {
+        breaking("Die Anschrift des Kunden ist unvollständig (Straße, PLZ, Ort)")
+    }
+    if (document.taxType === "13b UStG") {
+        if (document.customer && !text(customerInfo.ustid)) breaking("Für § 13b UStG muss beim Kunden eine USt-Id hinterlegt sein")
+        if (!text(businessInfo.vatId)) breaking("Für § 13b UStG muss in den Firmendaten eine USt-IdNr. hinterlegt sein")
+    }
+    if (!(document.rows || []).some(isItemRow)) breaking("Der Beleg enthält keine abrechenbaren Positionen")
+    if (document.payment_type === "direct-debit") {
+        if (!text(context.tenant?.creditorId)) breaking("Für SEPA-Lastschrift ist in den Firmendaten keine Gläubiger-ID hinterlegt")
+        if (!text(context.sepaMandate?.reference)) breaking("Für SEPA-Lastschrift ist kein Mandat mit Mandatsreferenz ausgewählt")
+    } else if ((document.payment_type === "transfer" || !document.payment_type) && !sellerIban(context)) {
+        breaking("Für Überweisung ist keine IBAN hinterlegt (Firmendaten oder Bankkonto)")
+    }
+    if (text(document.deliveryDateType) === "Kein Lieferdatum anzeigen") info("Es wird kein Liefer- oder Leistungsdatum angegeben (§ 14 UStG)")
+
+    return issues
+}
+
+export function buildZugferdInvoiceXml(document: any, context: ZugferdInvoiceContext): ZugferdInvoiceResult {
+    const businessInfo = context.tenant?.businessInfo || {}
+    const customer = context.customer || {}
+    const customerInfo = customer.infoData || {}
+    const address = document.address || {}
+    // Stornorechnungen tragen negative Preise; als Gutschrift (381) werden die Beträge positiv ausgewiesen.
+    const sign = document.type === "cancellationInvoices" ? -1 : 1
+
+    const issues = checkZugferdRequirements(document, context, { requireNumber: true })
+
+    const groups = new Map<string, TaxGroup>()
+    const lines: string[] = []
+    let lineIndex = 0
+
+    for (const row of document.rows || []) {
+        if (!isItemRow(row)) continue
+        lineIndex++
+        const discountPercent = Number(row.discountPercent) || 0
+        const grossUnitPrice = sign * (Number(row.price) || 0)
+        let netUnitPrice = grossUnitPrice * (1 - discountPercent / 100)
+        let quantity = Number(row.quantity) || 0
+        let grossPrice = grossUnitPrice
+        // EN 16931 verlangt nicht-negative Einzelpreise (BR-27); Minderungen laufen über eine negative Menge.
+        if (netUnitPrice < 0 || (netUnitPrice === 0 && grossPrice < 0)) {
+            netUnitPrice = -netUnitPrice
+            grossPrice = -grossPrice
+            quantity = -quantity
+        }
+        const lineTotal = round(quantity * netUnitPrice)
+        const rate = Number(row.taxPercent) || 0
+        const group = taxGroupFor(document.taxType, rate)
+        const key = `${group.category}:${group.rate}`
+        const existing = groups.get(key)
+        if (existing) existing.basis = round(existing.basis + lineTotal)
+        else groups.set(key, { ...group, basis: lineTotal })
+
+        const product = row.mode === "normal" ? context.products.find((item) => item.id === row.product) : null
+        const service = row.mode === "service" ? context.services.find((item) => item.id === row.service) : null
+        const name = text(product?.name || service?.name || row.text) || `Position ${row.pos ?? lineIndex}`
+        const sellerId = product?.article_number
+        const description = text(row.agriculture?.description || row.description)
+        const unit = context.units.find((item) => item.id === row.unit)
+        const allowance = round(grossPrice - netUnitPrice, 4)
+
+        lines.push(
+            `<ram:IncludedSupplyChainTradeLineItem>` +
+            `<ram:AssociatedDocumentLineDocument><ram:LineID>${escapeXml(text(row.pos) || String(lineIndex))}</ram:LineID></ram:AssociatedDocumentLineDocument>` +
+            `<ram:SpecifiedTradeProduct>${el("ram:SellerAssignedID", sellerId)}<ram:Name>${escapeXml(name)}</ram:Name>${el("ram:Description", description)}</ram:SpecifiedTradeProduct>` +
+            `<ram:SpecifiedLineTradeAgreement>` +
+            (allowance > 0
+                ? `<ram:GrossPriceProductTradePrice><ram:ChargeAmount>${decimal(grossPrice)}</ram:ChargeAmount><ram:AppliedTradeAllowanceCharge><ram:ChargeIndicator><udt:Indicator>false</udt:Indicator></ram:ChargeIndicator><ram:ActualAmount>${decimal(allowance)}</ram:ActualAmount></ram:AppliedTradeAllowanceCharge></ram:GrossPriceProductTradePrice>`
+                : "") +
+            `<ram:NetPriceProductTradePrice><ram:ChargeAmount>${decimal(netUnitPrice)}</ram:ChargeAmount></ram:NetPriceProductTradePrice>` +
+            `</ram:SpecifiedLineTradeAgreement>` +
+            `<ram:SpecifiedLineTradeDelivery><ram:BilledQuantity unitCode="${unitCode(unit)}">${decimal(quantity)}</ram:BilledQuantity></ram:SpecifiedLineTradeDelivery>` +
+            `<ram:SpecifiedLineTradeSettlement><ram:ApplicableTradeTax><ram:TypeCode>VAT</ram:TypeCode><ram:CategoryCode>${group.category}</ram:CategoryCode><ram:RateApplicablePercent>${decimal(group.rate)}</ram:RateApplicablePercent></ram:ApplicableTradeTax>` +
+            `<ram:SpecifiedTradeSettlementLineMonetarySummation><ram:LineTotalAmount>${amount(lineTotal)}</ram:LineTotalAmount></ram:SpecifiedTradeSettlementLineMonetarySummation></ram:SpecifiedLineTradeSettlement>` +
+            `</ram:IncludedSupplyChainTradeLineItem>`,
+        )
+    }
+
+    const taxGroups = [...groups.values()]
+    const lineNet = round(taxGroups.reduce((sum, group) => sum + group.basis, 0))
+    const taxTotal = round(taxGroups.reduce((sum, group) => sum + round(group.basis * group.rate / 100), 0))
+    const grossTotal = round(lineNet + taxTotal)
+    const prepaid = ["invoices", "cancellationInvoices"].includes(document.type)
+        ? round(context.advanceInvoices.reduce((sum, invoice) => sum + advanceInvoiceGross(invoice), 0))
+        : 0
+    const payable = round(grossTotal - prepaid)
+
+    // Zahlungsinformationen
+    const paymentAccount = context.bankAccounts.find((account) => !account.archived && !account.expired && account.iban)
+    const iban = text(businessInfo.iban || paymentAccount?.iban).replace(/\s+/g, "")
+    const bic = text(businessInfo.bic || paymentAccount?.bic).replace(/\s+/g, "")
+    const accountName = text(businessInfo.bankAccountOwner || paymentAccount?.ownerName || businessInfo.name)
+    let paymentMeans = ""
+    if (document.payment_type === "direct-debit") {
+        paymentMeans = `<ram:SpecifiedTradeSettlementPaymentMeans><ram:TypeCode>59</ram:TypeCode><ram:Information>SEPA-Lastschrift</ram:Information></ram:SpecifiedTradeSettlementPaymentMeans>`
+    } else if (document.payment_type === "transfer" || !document.payment_type) {
+        paymentMeans = `<ram:SpecifiedTradeSettlementPaymentMeans><ram:TypeCode>58</ram:TypeCode><ram:Information>SEPA-Überweisung</ram:Information>` +
+            (iban ? `<ram:PayeePartyCreditorFinancialAccount><ram:IBANID>${escapeXml(iban)}</ram:IBANID>${el("ram:AccountName", accountName)}</ram:PayeePartyCreditorFinancialAccount>` : "") +
+            (iban && bic ? `<ram:PayeeSpecifiedCreditorFinancialInstitution><ram:BICID>${escapeXml(bic)}</ram:BICID></ram:PayeeSpecifiedCreditorFinancialInstitution>` : "") +
+            `</ram:SpecifiedTradeSettlementPaymentMeans>`
+    } else {
+        paymentMeans = `<ram:SpecifiedTradeSettlementPaymentMeans><ram:TypeCode>1</ram:TypeCode></ram:SpecifiedTradeSettlementPaymentMeans>`
+    }
+
+    const paymentDays = document.paymentDays === null || document.paymentDays === undefined || document.paymentDays === "" ? null : Number(document.paymentDays)
+    const dueDate = date102(document.documentDate) && paymentDays !== null && Number.isFinite(paymentDays)
+        ? dayjs(document.documentDate).add(paymentDays, "day")
+        : null
+    const cashDiscount = ["invoices", "advanceInvoices"].includes(document.type)
+        ? buildCashDiscountTerms({ percent: document.cashDiscountPercent, days: document.cashDiscountDays, documentDate: document.documentDate, amount: payable })
+        : null
+    const termsDescription = [
+        payable <= 0 ? "" : dueDate ? `Zahlbar bis zum ${dueDate.format("DD.MM.YYYY")} ohne Abzug.` : "Zahlbar sofort ohne Abzug.",
+        // Strukturierte Skontoangabe nach XRechnung-Konvention, die von gängigen Empfängern ausgewertet wird.
+        cashDiscount && cashDiscount.days !== null
+            ? `#SKONTO#TAGE=${cashDiscount.days}#PROZENT=${cashDiscount.percent.toFixed(2)}#BASISBETRAG=${amount(payable)}#`
+            : "",
+    ].filter(Boolean).join("\n")
+    const paymentTerms = termsDescription || dueDate || context.sepaMandate?.reference
+        ? `<ram:SpecifiedTradePaymentTerms>${el("ram:Description", termsDescription)}${dueDate ? dateElement("ram:DueDateDateTime", dueDate.toDate()) : ""}${el("ram:DirectDebitMandateID", document.payment_type === "direct-debit" ? context.sepaMandate?.reference : "")}</ram:SpecifiedTradePaymentTerms>`
+        : ""
+
+    const taxElements = taxGroups.map((group) =>
+        `<ram:ApplicableTradeTax><ram:CalculatedAmount>${amount(group.basis * group.rate / 100)}</ram:CalculatedAmount><ram:TypeCode>VAT</ram:TypeCode>${el("ram:ExemptionReason", group.exemptionReason)}<ram:BasisAmount>${amount(group.basis)}</ram:BasisAmount><ram:CategoryCode>${group.category}</ram:CategoryCode>${el("ram:ExemptionReasonCode", group.exemptionReasonCode)}<ram:RateApplicablePercent>${decimal(group.rate)}</ram:RateApplicablePercent></ram:ApplicableTradeTax>`,
+    ).join("")
+
+    // Leistungsdatum bzw. Leistungszeitraum
+    const deliveryType = text(document.deliveryDateType)
+    const isPeriod = ["Lieferzeitraum", "Leistungszeitraum"].includes(deliveryType)
+    const showDelivery = deliveryType !== "Kein Lieferdatum anzeigen"
+    const deliveryEvent = showDelivery && !isPeriod && date102(document.deliveryDate)
+        ? `<ram:ActualDeliverySupplyChainEvent>${dateElement("ram:OccurrenceDateTime", document.deliveryDate)}</ram:ActualDeliverySupplyChainEvent>`
+        : ""
+    const billingPeriod = showDelivery && isPeriod && (date102(document.deliveryDate) || date102(document.deliveryDateEnd))
+        ? `<ram:BillingSpecifiedPeriod>${dateElement("ram:StartDateTime", document.deliveryDate)}${dateElement("ram:EndDateTime", document.deliveryDateEnd)}</ram:BillingSpecifiedPeriod>`
+        : ""
+
+    const contactPerson = context.contactPerson || {}
+    const sellerContact = tradeContact(contactPerson.full_name, document.contactTel || contactPerson.fixed_tel || contactPerson.mobile_tel || businessInfo.phone, contactPerson.email || businessInfo.email)
+    const seller = `<ram:SellerTradeParty>${el("ram:Name", businessInfo.name || context.tenant?.name)}${sellerContact}` +
+        partyAddress({ zip: businessInfo.zip, street: businessInfo.street, city: businessInfo.city, country: businessInfo.country }) +
+        (text(businessInfo.email) ? `<ram:URIUniversalCommunication><ram:URIID schemeID="EM">${escapeXml(text(businessInfo.email))}</ram:URIID></ram:URIUniversalCommunication>` : "") +
+        taxRegistrations(businessInfo.vatId, businessInfo.taxNumber) +
+        `</ram:SellerTradeParty>`
+
+    const buyerEmail = text(customerInfo.invoiceEmail || customerInfo.email)
+    const contact = context.contact
+    const buyer = `<ram:BuyerTradeParty>${el("ram:ID", typeof customer.customerNumber === "object" ? "" : customer.customerNumber)}${el("ram:Name", customer.name)}` +
+        (contact ? tradeContact([contact.firstName, contact.lastName].filter(Boolean).join(" "), contact.phoneHome || contact.phoneMobile, contact.email) : "") +
+        partyAddress({
+            zip: address.zip ?? customerInfo.zip,
+            street: address.street ?? customerInfo.street,
+            special: address.special ?? customerInfo.special,
+            city: address.city ?? customerInfo.city,
+            country: address.country ?? customerInfo.country,
+        }) +
+        (buyerEmail ? `<ram:URIUniversalCommunication><ram:URIID schemeID="EM">${escapeXml(buyerEmail)}</ram:URIID></ram:URIUniversalCommunication>` : "") +
+        taxRegistrations(customerInfo.ustid) +
+        `</ram:BuyerTradeParty>`
+
+    const contractReference = el("ram:IssuerAssignedID", context.contract?.contractNumber)
+    const projectReference = context.project?.name
+        ? `<ram:SpecifiedProcuringProject><ram:ID>${escapeXml(text(context.project.projectNumber || context.project.id))}</ram:ID><ram:Name>${escapeXml(text(context.project.name))}</ram:Name></ram:SpecifiedProcuringProject>`
+        : ""
+    const precedingInvoice = document.type === "cancellationInvoices" && text(context.linkedDocument?.documentNumber)
+        ? `<ram:InvoiceReferencedDocument><ram:IssuerAssignedID>${escapeXml(text(context.linkedDocument.documentNumber))}</ram:IssuerAssignedID>${date102(context.linkedDocument.documentDate) ? `<ram:FormattedIssueDateTime><qdt:DateTimeString format="102">${date102(context.linkedDocument.documentDate)}</qdt:DateTimeString></ram:FormattedIssueDateTime>` : ""}</ram:InvoiceReferencedDocument>`
+        : ""
+
+    const notes = [
+        text(document.title),
+        text(document.description),
+    ].filter(Boolean).map((note) => `<ram:IncludedNote><ram:Content>${escapeXml(note)}</ram:Content></ram:IncludedNote>`).join("")
+
+    const xml = `<?xml version="1.0" encoding="UTF-8"?>
+<rsm:CrossIndustryInvoice xmlns:rsm="urn:un:unece:uncefact:data:standard:CrossIndustryInvoice:100" xmlns:qdt="urn:un:unece:uncefact:data:standard:QualifiedDataType:100" xmlns:ram="urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:100" xmlns:udt="urn:un:unece:uncefact:data:standard:UnqualifiedDataType:100">` +
+        `<rsm:ExchangedDocumentContext><ram:GuidelineSpecifiedDocumentContextParameter><ram:ID>${ZUGFERD_GUIDELINE_ID}</ram:ID></ram:GuidelineSpecifiedDocumentContextParameter></rsm:ExchangedDocumentContext>` +
+        `<rsm:ExchangedDocument><ram:ID>${escapeXml(text(document.documentNumber))}</ram:ID><ram:TypeCode>${typeCode(document.type)}</ram:TypeCode>` +
+        `<ram:IssueDateTime><udt:DateTimeString format="102">${date102(document.documentDate) || dayjs().format("YYYYMMDD")}</udt:DateTimeString></ram:IssueDateTime>${notes}</rsm:ExchangedDocument>` +
+        `<rsm:SupplyChainTradeTransaction>${lines.join("")}` +
+        `<ram:ApplicableHeaderTradeAgreement>${el("ram:BuyerReference", context.project?.customerRef)}${seller}${buyer}` +
+        (contractReference ? `<ram:ContractReferencedDocument>${contractReference}</ram:ContractReferencedDocument>` : "") +
+        `${projectReference}</ram:ApplicableHeaderTradeAgreement>` +
+        `<ram:ApplicableHeaderTradeDelivery>${deliveryEvent}</ram:ApplicableHeaderTradeDelivery>` +
+        `<ram:ApplicableHeaderTradeSettlement>` +
+        (document.payment_type === "direct-debit" ? el("ram:CreditorReferenceID", context.tenant?.creditorId) : "") +
+        el("ram:PaymentReference", document.documentNumber) +
+        `<ram:InvoiceCurrencyCode>EUR</ram:InvoiceCurrencyCode>${paymentMeans}${taxElements}${billingPeriod}${paymentTerms}` +
+        `<ram:SpecifiedTradeSettlementHeaderMonetarySummation>` +
+        `<ram:LineTotalAmount>${amount(lineNet)}</ram:LineTotalAmount>` +
+        `<ram:TaxBasisTotalAmount>${amount(lineNet)}</ram:TaxBasisTotalAmount>` +
+        `<ram:TaxTotalAmount currencyID="EUR">${amount(taxTotal)}</ram:TaxTotalAmount>` +
+        `<ram:GrandTotalAmount>${amount(grossTotal)}</ram:GrandTotalAmount>` +
+        (prepaid ? `<ram:TotalPrepaidAmount>${amount(prepaid)}</ram:TotalPrepaidAmount>` : "") +
+        `<ram:DuePayableAmount>${amount(payable)}</ram:DuePayableAmount>` +
+        `</ram:SpecifiedTradeSettlementHeaderMonetarySummation>${precedingInvoice}` +
+        `</ram:ApplicableHeaderTradeSettlement></rsm:SupplyChainTradeTransaction></rsm:CrossIndustryInvoice>`
+
+    return { xml, issues, totals: { lineNet, tax: taxTotal, gross: grossTotal, prepaid, payable } }
+}

backend/src/modules/einvoice/embedZugferd.ts

@@ -0,0 +1,80 @@
+import { AFRelationship, PDFDocument, PDFName } from "pdf-lib"
+import { ZUGFERD_FILENAME } from "./buildZugferdInvoice"
+
+const escapeXml = (value: string) => value.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;")
+
+function buildXmp(title: string, now: Date) {
+    const date = now.toISOString()
+    return `<?xpacket begin="" id="W5M0MpCehiHzreSzNTczkc9d"?>
+<x:xmpmeta xmlns:x="adobe:ns:meta/">
+<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
+<rdf:Description rdf:about="" xmlns:dc="http://purl.org/dc/elements/1.1/">
+<dc:format>application/pdf</dc:format>
+<dc:title><rdf:Alt><rdf:li xml:lang="x-default">${escapeXml(title)}</rdf:li></rdf:Alt></dc:title>
+</rdf:Description>
+<rdf:Description rdf:about="" xmlns:xmp="http://ns.adobe.com/xap/1.0/">
+<xmp:CreatorTool>FEDEO</xmp:CreatorTool>
+<xmp:CreateDate>${date}</xmp:CreateDate>
+<xmp:ModifyDate>${date}</xmp:ModifyDate>
+<xmp:MetadataDate>${date}</xmp:MetadataDate>
+</rdf:Description>
+<rdf:Description rdf:about="" xmlns:pdf="http://ns.adobe.com/pdf/1.3/">
+<pdf:Producer>FEDEO</pdf:Producer>
+</rdf:Description>
+<rdf:Description rdf:about="" xmlns:fx="urn:factur-x:pdfa:CrossIndustryDocument:invoice:1p0#">
+<fx:DocumentType>INVOICE</fx:DocumentType>
+<fx:DocumentFileName>${ZUGFERD_FILENAME}</fx:DocumentFileName>
+<fx:Version>1.0</fx:Version>
+<fx:ConformanceLevel>EN 16931</fx:ConformanceLevel>
+</rdf:Description>
+<rdf:Description rdf:about="" xmlns:pdfaExtension="http://www.aiim.org/pdfa/ns/extension/" xmlns:pdfaSchema="http://www.aiim.org/pdfa/ns/schema#" xmlns:pdfaProperty="http://www.aiim.org/pdfa/ns/property#">
+<pdfaExtension:schemas><rdf:Bag><rdf:li rdf:parseType="Resource">
+<pdfaSchema:schema>Factur-X PDFA Extension Schema</pdfaSchema:schema>
+<pdfaSchema:namespaceURI>urn:factur-x:pdfa:CrossIndustryDocument:invoice:1p0#</pdfaSchema:namespaceURI>
+<pdfaSchema:prefix>fx</pdfaSchema:prefix>
+<pdfaSchema:property><rdf:Seq>
+<rdf:li rdf:parseType="Resource"><pdfaProperty:name>DocumentFileName</pdfaProperty:name><pdfaProperty:valueType>Text</pdfaProperty:valueType><pdfaProperty:category>external</pdfaProperty:category><pdfaProperty:description>name of the embedded XML invoice file</pdfaProperty:description></rdf:li>
+<rdf:li rdf:parseType="Resource"><pdfaProperty:name>DocumentType</pdfaProperty:name><pdfaProperty:valueType>Text</pdfaProperty:valueType><pdfaProperty:category>external</pdfaProperty:category><pdfaProperty:description>INVOICE</pdfaProperty:description></rdf:li>
+<rdf:li rdf:parseType="Resource"><pdfaProperty:name>Version</pdfaProperty:name><pdfaProperty:valueType>Text</pdfaProperty:valueType><pdfaProperty:category>external</pdfaProperty:category><pdfaProperty:description>The actual version of the Factur-X XML schema</pdfaProperty:description></rdf:li>
+<rdf:li rdf:parseType="Resource"><pdfaProperty:name>ConformanceLevel</pdfaProperty:name><pdfaProperty:valueType>Text</pdfaProperty:valueType><pdfaProperty:category>external</pdfaProperty:category><pdfaProperty:description>The conformance level of the embedded Factur-X data</pdfaProperty:description></rdf:li>
+</rdf:Seq></pdfaSchema:property>
+</rdf:li></rdf:Bag></pdfaExtension:schemas>
+</rdf:Description>
+</rdf:RDF>
+</x:xmpmeta>
+<?xpacket end="w"?>`
+}
+
+/**
+ * Bettet das CII-XML als factur-x.xml (AFRelationship Alternative) in die PDF ein und ergänzt die
+ * Factur-X/ZUGFeRD-XMP-Metadaten. Ergebnis ist eine hybride ZUGFeRD-Rechnung (PDF + strukturierte Daten).
+ */
+export async function embedZugferdXml(pdfBytes: Uint8Array | Buffer, xml: string, options: { title?: string } = {}) {
+    const pdfDoc = await PDFDocument.load(pdfBytes, { updateMetadata: false })
+    const now = new Date()
+    const title = options.title || "Rechnung"
+
+    await pdfDoc.attach(Buffer.from(xml, "utf8"), ZUGFERD_FILENAME, {
+        mimeType: "text/xml",
+        description: "Factur-X/ZUGFeRD Rechnung",
+        creationDate: now,
+        modificationDate: now,
+        afRelationship: AFRelationship.Alternative,
+    })
+
+    pdfDoc.setTitle(title, { showInWindowTitleBar: true })
+    pdfDoc.setProducer("FEDEO")
+    pdfDoc.setCreator("FEDEO")
+    pdfDoc.setCreationDate(now)
+    pdfDoc.setModificationDate(now)
+    pdfDoc.setLanguage("de-DE")
+
+    const metadata = pdfDoc.context.stream(Buffer.from(buildXmp(title, now), "utf8"), {
+        Type: "Metadata",
+        Subtype: "XML",
+    })
+    pdfDoc.catalog.set(PDFName.of("Metadata"), pdfDoc.context.register(metadata))
+    pdfDoc.setSubject("ZUGFeRD / Factur-X EN 16931")
+
+    return Buffer.from(await pdfDoc.save({ useObjectStreams: false }))
+}

backend/src/modules/einvoice/mapElectronicInvoice.ts

@@ -41,6 +41,13 @@ export const findElectronicInvoiceVendor = async (
     return null
 }
 
+const addDaysToDate = (date: string, days: number) => {
+    const parsed = new Date(`${String(date).slice(0, 10)}T00:00:00Z`)
+    if (Number.isNaN(parsed.getTime())) return null
+    parsed.setUTCDate(parsed.getUTCDate() + days)
+    return parsed.toISOString().slice(0, 10)
+}
+
 export const mapElectronicInvoiceToIncomingInvoice = (
     invoice: ParsedElectronicInvoice,
     tenantId: number,
@@ -64,6 +71,10 @@ export const mapElectronicInvoiceToIncomingInvoice = (
         reference: invoice.invoiceNumber,
         date: invoice.invoiceDate,
         dueDate: invoice.dueDate,
+        cashDiscountPercent: invoice.cashDiscount?.percent ?? null,
+        cashDiscountDueDate: invoice.cashDiscount && invoice.invoiceDate
+            ? addDaysToDate(invoice.invoiceDate, invoice.cashDiscount.days)
+            : null,
         paymentType: paymentTypeByCode[invoice.paymentMeansCode || ""] || "Sonstiges",
         description: descriptionParts.join("\n"),
         accounts: invoice.items.map((item) => ({

backend/src/modules/einvoice/outgoingZugferd.service.ts

@@ -0,0 +1,106 @@
+import { FastifyInstance } from "fastify"
+import { and, eq, inArray } from "drizzle-orm"
+import {
+    authProfiles,
+    bankaccounts,
+    contacts,
+    contracts,
+    createddocuments,
+    customers,
+    outgoingsepamandates,
+    products,
+    projects,
+    services,
+    tenants,
+    units,
+} from "../../../db/schema"
+import { buildZugferdInvoiceXml, checkZugferdRequirements, ZUGFERD_DOCUMENT_TYPES, ZugferdInvoiceContext, ZugferdIssue } from "./buildZugferdInvoice"
+import { embedZugferdXml } from "./embedZugferd"
+
+export const isZugferdDocumentType = (type: unknown) => ZUGFERD_DOCUMENT_TYPES.includes(String(type))
+export const isZugferdDocument = (document: any) => Boolean(document && isZugferdDocumentType(document.type) && document.documentNumber)
+
+export class EInvoiceRequirementsError extends Error {
+    statusCode = 422
+    code = "EINVOICE_REQUIREMENTS"
+    constructor(public issues: ZugferdIssue[]) {
+        super(`Die E-Rechnung kann nicht erstellt werden: ${issues.map((issue) => issue.message.replace(/^E-Rechnung: /, "")).join("; ")}`)
+    }
+}
+
+export const breakingIssues = (issues: ZugferdIssue[]) => issues.filter((issue) => issue.type === "breaking")
+
+/** Prüft die Pflichtangaben eines (auch ungespeicherten) Belegs. Andere Belegarten liefern keine Hinweise. */
+export async function checkOutgoingEInvoice(server: FastifyInstance, tenantId: number, document: any, options: { requireNumber?: boolean } = {}) {
+    if (!document || !isZugferdDocumentType(document.type)) return [] as ZugferdIssue[]
+    const context = await loadZugferdContext(server, tenantId, document)
+    return checkZugferdRequirements(document, context, options)
+}
+
+/** Wirft EInvoiceRequirementsError, wenn Pflichtangaben fehlen. */
+export async function assertOutgoingEInvoiceRequirements(server: FastifyInstance, tenantId: number, document: any, options: { requireNumber?: boolean } = {}) {
+    const blocking = breakingIssues(await checkOutgoingEInvoice(server, tenantId, document, options))
+    if (blocking.length) throw new EInvoiceRequirementsError(blocking)
+}
+
+const byId = async (server: FastifyInstance, table: any, id: unknown, tenantId: number) => {
+    if (id === null || id === undefined || id === "") return null
+    const [row] = await server.db.select().from(table).where(and(eq(table.id, Number(id)), eq(table.tenant, tenantId))).limit(1)
+    return row || null
+}
+
+export async function loadZugferdContext(server: FastifyInstance, tenantId: number, document: any): Promise<ZugferdInvoiceContext> {
+    const rows = document.rows || []
+    const productIds = [...new Set(rows.filter((row: any) => row.product).map((row: any) => Number(row.product)))] as number[]
+    const serviceIds = [...new Set(rows.filter((row: any) => row.service).map((row: any) => Number(row.service)))] as number[]
+    const advanceIds = (Array.isArray(document.usedAdvanceInvoices) ? document.usedAdvanceInvoices : []).map(Number) as number[]
+    const profileUser = document.contactPerson || document.created_by
+
+    const [[tenant], customer, contact, project, contract, linkedDocument, sepaMandate, unitRows, productRows, serviceRows, bankAccountRows, advanceRows, profileRows] = await Promise.all([
+        server.db.select().from(tenants).where(eq(tenants.id, tenantId)).limit(1),
+        byId(server, customers, document.customer, tenantId),
+        byId(server, contacts, document.contact, tenantId),
+        byId(server, projects, document.project, tenantId),
+        byId(server, contracts, document.contract, tenantId),
+        byId(server, createddocuments, document.createddocument ?? document.linkedDocument, tenantId),
+        byId(server, outgoingsepamandates, document.outgoingsepamandate, tenantId),
+        server.db.select().from(units),
+        productIds.length ? server.db.select().from(products).where(and(eq(products.tenant, tenantId), inArray(products.id, productIds))) : [],
+        serviceIds.length ? server.db.select().from(services).where(and(eq(services.tenant, tenantId), inArray(services.id, serviceIds))) : [],
+        server.db.select().from(bankaccounts).where(and(eq(bankaccounts.tenant, tenantId), eq(bankaccounts.archived, false))),
+        advanceIds.length ? server.db.select().from(createddocuments).where(and(eq(createddocuments.tenant, tenantId), inArray(createddocuments.id, advanceIds))) : [],
+        profileUser
+            ? server.db.select().from(authProfiles).where(and(eq(authProfiles.user_id, profileUser), eq(authProfiles.tenant_id, tenantId))).limit(1)
+            : [],
+    ])
+
+    return {
+        tenant,
+        customer,
+        contact,
+        contactPerson: (profileRows as any[])[0] || null,
+        project,
+        contract,
+        linkedDocument,
+        sepaMandate,
+        units: unitRows,
+        products: productRows as any[],
+        services: serviceRows as any[],
+        bankAccounts: bankAccountRows,
+        advanceInvoices: advanceIds.map((id) => (advanceRows as any[]).find((invoice) => invoice.id === id)).filter(Boolean),
+    }
+}
+
+/**
+ * Macht aus der gerenderten Rechnungs-PDF eine ZUGFeRD-Rechnung. Fehlende Pflichtangaben führen zu
+ * EInvoiceRequirementsError, damit keine Rechnung ohne gültige E-Rechnung abgelegt wird.
+ */
+export async function attachZugferdToPdf(server: FastifyInstance, tenantId: number, document: any, pdf: Buffer) {
+    if (!isZugferdDocument(document)) return { pdf, issues: [] as ZugferdIssue[], einvoice: false }
+    const context = await loadZugferdContext(server, tenantId, document)
+    const { xml, issues } = buildZugferdInvoiceXml(document, context)
+    const blocking = breakingIssues(issues)
+    if (blocking.length) throw new EInvoiceRequirementsError(blocking)
+    const result = await embedZugferdXml(pdf, xml, { title: document.title || `Rechnung ${document.documentNumber}` })
+    return { pdf: result, issues, einvoice: true }
+}

backend/src/modules/einvoice/parseElectronicInvoice.ts

@@ -1,6 +1,7 @@
 import { XMLParser } from "fast-xml-parser"
 import type { ElectronicInvoiceSyntax } from "./detectElectronicInvoice"
 import type { ElectronicInvoiceItem, ParsedElectronicInvoice } from "./types"
+import { parseCashDiscountPaymentTerms } from "../cash-discount"
 
 const parser = new XMLParser({
     ignoreAttributes: false,
@@ -83,7 +84,9 @@ const parseCii = (root: any): Omit<ParsedElectronicInvoice, "validation"> => {
     })
 
     const paymentMeans = array(settlement?.SpecifiedTradeSettlementPaymentMeans)[0] || {}
-    const paymentTerms = array(settlement?.SpecifiedTradePaymentTerms)[0] || {}
+    const paymentTermsList = array(settlement?.SpecifiedTradePaymentTerms)
+    const paymentTerms = paymentTermsList[0] || {}
+    const cashDiscount = ciiCashDiscount(paymentTermsList)
     const guideline = root?.ExchangedDocumentContext?.GuidelineSpecifiedDocumentContextParameter?.ID
 
     return {
@@ -103,6 +106,7 @@ const parseCii = (root: any): Omit<ParsedElectronicInvoice, "validation"> => {
         },
         buyerReference: text(agreement?.BuyerReference),
         paymentMeansCode: text(paymentMeans?.TypeCode),
+        cashDiscount,
         items,
         totals: {
             lineNet: number(monetary?.LineTotalAmount) != null ? roundMoney(sign * number(monetary.LineTotalAmount)!) : null,
@@ -113,6 +117,18 @@ const parseCii = (root: any): Omit<ParsedElectronicInvoice, "validation"> => {
     }
 }
 
+// Skonto steht in XRechnung als "#SKONTO#TAGE=14#PROZENT=2.00#" im Zahlungsbedingungstext,
+// in ZUGFeRD EXTENDED zusätzlich strukturiert als ApplicableTradePaymentDiscountTerms.
+const ciiCashDiscount = (paymentTermsList: any[]) => {
+    for (const terms of paymentTermsList) {
+        const discountTerms = array(terms?.ApplicableTradePaymentDiscountTerms)[0]
+        const percent = number(discountTerms?.CalculationPercent)
+        const days = number(discountTerms?.BasisPeriodMeasure)
+        if (percent && percent > 0 && days !== null && Number.isInteger(days)) return { percent, days }
+    }
+    return parseCashDiscountPaymentTerms(paymentTermsList.flatMap((terms: any) => array(terms?.Description).map(text)).join("\n"))
+}
+
 const ublPartyName = (party: any) => text(party?.PartyLegalEntity?.RegistrationName) || text(party?.PartyName?.Name)
 
 const parseUbl = (root: any, syntax: "ubl-invoice" | "ubl-credit-note"): Omit<ParsedElectronicInvoice, "validation"> => {
@@ -163,6 +179,7 @@ const parseUbl = (root: any, syntax: "ubl-invoice" | "ubl-credit-note"): Omit<Pa
         },
         buyerReference: text(root?.BuyerReference),
         paymentMeansCode: text(paymentMeans?.PaymentMeansCode),
+        cashDiscount: parseCashDiscountPaymentTerms(array(root?.PaymentTerms).flatMap((terms: any) => array(terms?.Note).map(text)).join("\n")),
         items,
         totals: {
             lineNet: number(monetary?.LineExtensionAmount) != null ? roundMoney(sign * number(monetary.LineExtensionAmount)!) : null,

backend/src/modules/einvoice/types.ts

@@ -28,6 +28,7 @@ export type ParsedElectronicInvoice = {
     }
     buyerReference: string | null
     paymentMeansCode: string | null
+    cashDiscount?: { percent: number, days: number } | null
     items: ElectronicInvoiceItem[]
     totals: {
         lineNet: number | null

backend/src/modules/outgoing-document-pdf.service.ts

@@ -18,6 +18,7 @@ import {
 } from "../../db/schema"
 import { documentTemplateHandlebars } from "../utils/handlebars"
 import { createInvoicePDF, InvoicePdfLayout } from "../utils/pdf"
+import { appendCashDiscountText, buildCashDiscountTerms, getCashDiscountTemplateContext } from "./cash-discount"
 
 const quoteLikeDocumentTypes = ["quotes", "costEstimates"]
 const deliveryNoteLikeDocumentTypes = ["deliveryNotes", "packingSlips"]
@@ -130,6 +131,15 @@ export function buildOutgoingDocumentPdfData(source: any, data: OutgoingDocument
     }
 
     const totals = calculateOutgoingDocumentTotals(document, data.advanceInvoices)
+    // Skonto bezieht sich bei Schlussrechnungen auf die Restforderung nach Abzug der Abschläge.
+    const cashDiscountTerms = ["invoices", "advanceInvoices"].includes(document.type)
+        ? buildCashDiscountTerms({
+            percent: document.cashDiscountPercent,
+            days: document.cashDiscountDays,
+            documentDate: document.documentDate,
+            amount: document.type === "invoices" ? totals.totalSumToPay : totals.totalGross,
+        })
+        : null
     const rows = document.rows.map((row: any) => {
         if (!["pagebreak", "title"].includes(row.mode)) {
             if (row.agriculture?.description) row.descriptionText = row.agriculture.description
@@ -160,6 +170,7 @@ export function buildOutgoingDocumentPdfData(source: any, data: OutgoingDocument
         zahlungsziel_in_tagen: document.paymentDays,
         zahlungsart: document.payment_type === "transfer" ? "Überweisung" : "Lastschrift",
         diesel_gesamtverbrauch: document.agriculture?.dieselUsageTotal,
+        ...getCashDiscountTemplateContext(cashDiscountTerms),
     }
     const formatDate = (value: any) => value ? dayjs(value).format("DD.MM.YYYY") : "XXXX"
     const formatSums = (sums: Record<string, number>) => Object.fromEntries(Object.entries(sums).map(([key, value]) => [key, renderCurrency(value)]))
@@ -198,7 +209,7 @@ export function buildOutgoingDocumentPdfData(source: any, data: OutgoingDocument
         ],
         title: document.title,
         description: document.description,
-        endText: documentTemplateHandlebars.compile(document.endText || "")(context),
+        endText: appendCashDiscountText(documentTemplateHandlebars.compile(document.endText || "")(context), document.endText, cashDiscountTerms),
         startText: documentTemplateHandlebars.compile(document.startText || "")(context),
         rows,
         totalArray: [

backend/src/modules/serialexecution.service.ts

@@ -9,7 +9,9 @@ import { saveFile } from "../utils/files";
 import {FastifyInstance} from "fastify";
 import {useNextNumberRangeNumber} from "../utils/functions";
 import {createInvoicePDF} from "../utils/pdf"; // Achtung: Muss Node.js Buffer unterstützen!
+import { assertOutgoingEInvoiceRequirements, attachZugferdToPdf, EInvoiceRequirementsError } from "./einvoice/outgoingZugferd.service";
 import { documentTemplateHandlebars } from "../utils/handlebars";
+import { appendCashDiscountText, buildCashDiscountTerms, getCashDiscountTemplateContext } from "./cash-discount"
 
 dayjs.extend(quarterOfYear);
 
@@ -200,6 +202,7 @@ export const finishManualGeneration = async (server: FastifyInstance, executionI
 
         let successCount = 0;
         let errorCount = 0;
+        const einvoiceErrors: string[] = [];
 
         // 5. Loop durch Dokumente
         for (const doc of documents) {
@@ -215,6 +218,9 @@ export const finishManualGeneration = async (server: FastifyInstance, executionI
                     doc.letterhead ? fetchById(server, schema.letterheads, doc.letterhead) : null
                 ]);
 
+                // Pflichtangaben vor der Nummernvergabe prüfen, damit keine Lücken im Nummernkreis entstehen
+                await assertOutgoingEInvoiceRequirements(server, tenantId, doc);
+
                 const pdfData = await getCloseData(
                     server,
                     doc,
@@ -232,8 +238,14 @@ export const finishManualGeneration = async (server: FastifyInstance, executionI
                 console.log(pdfBase64);
 
                 // E. Datei speichern
+                // E-Rechnung (ZUGFeRD) in die PDF einbetten; Grundlage ist der Beleg mit der neuen Nummer
+                const { pdf: fileBuffer } = await attachZugferdToPdf(
+                    server,
+                    tenantId,
+                    { ...doc, state: "Gebucht", documentNumber: pdfData.documentNumber, title: pdfData.title },
                     // @ts-ignore
-                const fileBuffer = Buffer.from(pdfBase64.base64, "base64");
+                    Buffer.from(pdfBase64.base64, "base64"),
+                );
                 const filename = `${pdfData.documentNumber}.pdf`;
 
                 await saveFile(
@@ -266,6 +278,7 @@ export const finishManualGeneration = async (server: FastifyInstance, executionI
             } catch (innerErr) {
                 console.error(`Fehler beim Finalisieren von Doc ID ${doc.id}:`, innerErr);
                 errorCount++;
+                if (innerErr instanceof EInvoiceRequirementsError) einvoiceErrors.push(`Beleg ${doc.id}: ${innerErr.message}`);
                 // Optional: Status des einzelnen Dokuments auf Error setzen
             }
         }
@@ -275,7 +288,7 @@ export const finishManualGeneration = async (server: FastifyInstance, executionI
 
 
         const execution = await settleExecution(server, executionId, tenantId, finalStatus,
-            `Abgeschlossen: ${successCount} erfolgreich, ${errorCount} Fehler.`);
+            `Abgeschlossen: ${successCount} erfolgreich, ${errorCount} Fehler.${einvoiceErrors.length ? ` ${einvoiceErrors.join(" ")}` : ""}`);
         return { success: execution.status === "completed", execution, processed: successCount, errors: errorCount };
     } catch (error) {
         await settleExecution(server, executionId, tenantId, "error", "Kritischer Fehler beim Finalisieren.");
@@ -421,6 +434,8 @@ async function getSaveData(item: any, tenant: any, firstDate: string, lastDate:
         deliveryDate: firstDate,
         deliveryDateEnd: lastDate,
         paymentDays: item.paymentDays,
+        cashDiscountPercent: item.cashDiscountPercent,
+        cashDiscountDays: item.cashDiscountDays,
         payment_type: item.payment_type,
         deliveryDateType: item.deliveryDateType,
         info: {}, // Achtung: Postgres erwartet hier valides JSON Objekt
@@ -646,6 +661,12 @@ export function getDocumentDataBackend(
 
 
     // --- 5. Handlebars Context ---
+    const cashDiscountTerms = buildCashDiscountTerms({
+        percent: itemInfo.cashDiscountPercent,
+        days: itemInfo.cashDiscountDays,
+        documentDate: itemInfo.documentDate ? dayjs(itemInfo.documentDate).format("YYYY-MM-DD") : null,
+        amount: totals.totalGross,
+    });
     const generateContext = () => {
         return {
             // lohnkosten: null, // Backend hat diesen Wert oft nicht direkt, ggf. aus itemInfo holen
@@ -656,7 +677,8 @@ export function getDocumentDataBackend(
             kundenname: customerData && customerData.name,
             zahlungsziel_in_tagen: itemInfo.paymentDays,
             zahlungsart: itemInfo.payment_type === "transfer" ? "Überweisung" : "Lastschrift",
-            diesel_gesamtverbrauch: (itemInfo.agriculture && itemInfo.agriculture.dieselUsageTotal) || null
+            diesel_gesamtverbrauch: (itemInfo.agriculture && itemInfo.agriculture.dieselUsageTotal) || null,
+            ...getCashDiscountTemplateContext(cashDiscountTerms),
         };
     };
 
@@ -756,7 +778,7 @@ export function getDocumentDataBackend(
         title: itemInfo.title,
         description: itemInfo.description,
         // Handlebars Compilation ausführen
-        endText: templateEndText(generateContext()),
+        endText: appendCashDiscountText(templateEndText(generateContext()), itemInfo.endText, cashDiscountTerms),
         startText: templateStartText(generateContext()),
         rows: rows,
         totalArray: totalArray,

backend/src/routes/banking.ts

@@ -11,6 +11,7 @@ import { centralServicesClient } from "../modules/push-server.client"
 import { findBankInstitutionByBic } from "../modules/banking-institution"
 import { normalizeBankAllocationDetails, validateBankAllocationCostCentre } from "../modules/bank-allocation-details"
 import { CASHBOOK_BANK_ID } from "../modules/bank-balances.service"
+import { prepareCashDiscountAllocation, settledAllocationAmount } from "../modules/cash-discount"
 
 import {
     bankrequisitions,
@@ -56,7 +57,7 @@ export default async function bankingRoutes(server: FastifyInstance) {
                 eq(bankstatements.id, statementId),
                 eq(bankstatements.tenant, tenantId)
             )).limit(1),
-            server.db.select({ amount: statementallocations.amount }).from(statementallocations).where(and(
+            server.db.select({ amount: statementallocations.amount, cashDiscountAmount: statementallocations.cashDiscountAmount }).from(statementallocations).where(and(
                 eq(statementallocations.incominginvoice, invoiceId),
                 eq(statementallocations.tenant, tenantId),
                 eq(statementallocations.archived, false)
@@ -77,10 +78,9 @@ export default async function bankingRoutes(server: FastifyInstance) {
         const correctedTax = invoice.taxAmountOverride !== null && invoice.taxAmountOverride !== undefined && invoice.taxAmountOverride !== ""
             ? Number(invoice.taxAmountOverride)
             : accountTotals.tax
-        const legacyRemaining = Math.max(0, Math.abs(accountTotals.net + accountTotals.tax)
+        const invoiceSettled = invoiceAllocations.reduce((sum, item) => sum + Math.abs(settledAllocationAmount(item)), 0)
-            - invoiceAllocations.reduce((sum, item) => sum + Math.abs(Number(item.amount || 0)), 0))
+        const legacyRemaining = Math.max(0, Math.abs(accountTotals.net + accountTotals.tax) - invoiceSettled)
-        const correctedRemaining = Math.max(0, Math.abs(accountTotals.net + correctedTax)
+        const correctedRemaining = Math.max(0, Math.abs(accountTotals.net + correctedTax) - invoiceSettled)
-            - invoiceAllocations.reduce((sum, item) => sum + Math.abs(Number(item.amount || 0)), 0))
         const statementRemaining = Math.max(0, Math.abs(Number(statement.amount || 0))
             - statementAllocations.reduce((sum, item) => sum + Math.abs(Number(item.amount || 0)), 0))
         const requestedAmount = Number(allocation.amount || 0)
@@ -1168,7 +1168,10 @@ export default async function bankingRoutes(server: FastifyInstance) {
             if (prepared.error) return reply.code(400).send({ error: prepared.error })
             Object.assign(prepared.data, normalizeBankAllocationDetails(prepared.data))
             await validateBankAllocationCostCentre(server.db, req.user.tenant_id, prepared.data.costcentre)
+            if (!Number(prepared.data.cashDiscountAmount || 0)) {
                 prepared.data = await useCurrentIncomingInvoiceAmount(req.user.tenant_id, prepared.data)
+            }
+            prepared.data = await prepareCashDiscountAllocation(server.db, req.user.tenant_id, prepared.data)
 
             const inserted = await server.db.insert(statementallocations).values({
                 ...prepared.data,

backend/src/routes/functions.ts

@@ -18,7 +18,8 @@ import isSameOrBefore from "dayjs/plugin/isSameOrBefore.js"
 import duration from "dayjs/plugin/duration.js";
 import timezone from "dayjs/plugin/timezone.js";
 import {generateTimesEvaluation} from "../modules/time/evaluation.service";
-import {citys, files} from "../../db/schema";
+import {citys, createddocuments, files} from "../../db/schema";
+import { attachZugferdToPdf, checkOutgoingEInvoice, EInvoiceRequirementsError } from "../modules/einvoice/outgoingZugferd.service";
 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";
@@ -110,6 +111,8 @@ export default async function functionRoutes(server: FastifyInstance) {
         const body = req.body as {
             data: any
             backgroundPath?: string
+            // Gespeicherter Beleg, aus dem die eingebettete E-Rechnung (ZUGFeRD) erzeugt wird
+            createdDocumentId?: number
         }
         const {type} = req.params as {type:string}
 
@@ -125,6 +128,17 @@ export default async function functionRoutes(server: FastifyInstance) {
                     body.data,
                     body.backgroundPath
                 )
+                if (body.createdDocumentId) {
+                    const tenantId = (req as any).user.tenant_id
+                    const [document] = await server.db
+                        .select()
+                        .from(createddocuments)
+                        .where(and(eq(createddocuments.id, Number(body.createdDocumentId)), eq(createddocuments.tenant, tenantId)))
+                        .limit(1)
+                    if (!document) return reply.code(404).send({ error: "Beleg nicht gefunden" })
+                    const result = await attachZugferdToPdf(server, tenantId, document, Buffer.from(pdf.base64, "base64"))
+                    pdf = { ...pdf, base64: result.pdf.toString("base64"), einvoice: result.einvoice, einvoiceIssues: result.issues }
+                }
             } else if(type === "timesheet") {
                 pdf = await createTimeSheetPDF(
                     server,
@@ -136,6 +150,9 @@ export default async function functionRoutes(server: FastifyInstance) {
 
             return pdf // Fastify wandelt automatisch in JSON
         } catch (err) {
+            if (err instanceof EInvoiceRequirementsError) {
+                return reply.code(422).send({ error: err.message, code: err.code, issues: err.issues })
+            }
             console.log(err)
             const unsupportedCharacterMessage = getUnsupportedPdfCharacterMessage(err, body.data)
             if (unsupportedCharacterMessage) {
@@ -149,6 +166,14 @@ export default async function functionRoutes(server: FastifyInstance) {
         }
     })
 
+    // Prüft die Pflichtangaben der E-Rechnung für den aktuellen (ggf. ungespeicherten) Stand aus dem Editor
+    server.post("/functions/einvoice/check", async (req, reply) => {
+        const { document } = (req.body || {}) as { document?: any }
+        if (!document || typeof document !== "object") return reply.code(400).send({ error: "document fehlt" })
+        const issues = await checkOutgoingEInvoice(server, (req as any).user.tenant_id, document)
+        return { issues }
+    })
+
     server.get("/functions/usenextnumber/:numberrange", async (req, reply) => {
             const { numberrange } = req.params as { numberrange: string };
             const tenant = (req as any).user.tenant_id

backend/src/routes/resources/main.ts

@@ -507,6 +507,7 @@ export default async function resourceRoutes(server: FastifyInstance) {
                     id: statementallocations.id,
                     createddocument: statementallocations.createddocument,
                     amount: statementallocations.amount,
+                    cashDiscountAmount: statementallocations.cashDiscountAmount,
                 })
                 .from(statementallocations)
                 .where(and(

backend/src/routes/tenant.ts

@@ -15,6 +15,7 @@ import {and, desc, eq, inArray, isNull} from "drizzle-orm"
 import { enrichProfilesWithBranches } from "../utils/profileBranches"
 import { enrichProfilesWithTeams } from "../utils/profileTeams"
 import { rotateRefreshToken } from "../utils/authTokens"
+import { normalizeCashDiscountAccountsInput } from "../modules/cash-discount"
 
 
 export default async function tenantRoutes(server: FastifyInstance) {
@@ -287,6 +288,14 @@ export default async function tenantRoutes(server: FastifyInstance) {
                 delete data.portalConfig.primayColor
             }
 
+            if (Object.prototype.hasOwnProperty.call(data, "cashDiscountAccounts")) {
+                try {
+                    data.cashDiscountAccounts = normalizeCashDiscountAccountsInput(data.cashDiscountAccounts)
+                } catch (err: any) {
+                    return reply.code(400).send({ error: err.message })
+                }
+            }
+
             const updated = await server.db
                 .update(tenants)
                 .set(data)

backend/src/utils/export/datev.ts

@@ -104,6 +104,51 @@ export const getBankAccountBookingLine = (alloc: any) => {
     return columns.join(";");
 };
 
+// Skonto als eigene Buchung je Steuersatz: Skontokonto (Automatikkonto) gegen Debitor bzw. Kreditor.
+// Positiver Skonto (Zahlungseingang) steht im Soll des Skontokontos, negativer (Zahlungsausgang) im Haben.
+export const getCashDiscountBookingLines = (alloc: any) => {
+    const split = Array.isArray(alloc?.cashDiscountSplit) ? alloc.cashDiscountSplit : [];
+    if (!split.length) return [];
+
+    const bs = alloc.bankstatement;
+    const cd = alloc.createddocument;
+    const ii = alloc.incominginvoice;
+    const partner = cd ? cd.customer : ii?.vendor;
+    const partnerNumber = cd ? partner?.customerNumber : partner?.vendorNumber;
+    const reference = cd ? cd.documentNumber : ii?.reference;
+    const prefix = cd ? "Skonto AR" : "Skonto ER";
+    const date = bs?.date || alloc.manualBookingDate;
+    const quote = (value: any) => `"${escapeString(String(value ?? ""))}"`;
+
+    return split
+        .filter((item: any) => Number(item?.gross) && item?.account)
+        .map((item: any) => {
+            const columns = Array(124).fill("");
+            columns[0] = displayCurrency(Number(item.gross), true);
+            columns[1] = quote(Number(item.gross) > 0 ? "S" : "H");
+            columns[6] = item.account;
+            columns[7] = partnerNumber || "";
+            columns[8] = quote("");
+            columns[9] = formatDatevDate(date, "DDMM");
+            columns[10] = quote(reference || "");
+            columns[13] = quote(`${prefix} ${reference || ""} ${item.rate} % - ${partner?.name || ""}`.substring(0, 59));
+            columns[20] = quote("Geschäftspartner");
+            columns[21] = quote(partner?.name || "");
+            columns[22] = quote("Kundennummer");
+            columns[23] = quote(partnerNumber || "");
+            columns[24] = quote("Belegnummer");
+            columns[25] = quote(reference || "");
+            columns[28] = quote("Belegdatum");
+            columns[29] = quote(formatDatevDate(date, "DD.MM.YYYY"));
+            if (bs?.id) {
+                columns[47] = "Bank-Id";
+                columns[48] = bs.id;
+            }
+            columns[112] = "0";
+            return columns.join(";");
+        });
+};
+
 const getIncomingInvoiceTaxOverride = (invoice: any) => {
     if (invoice.taxAmountOverride === null || invoice.taxAmountOverride === undefined || invoice.taxAmountOverride === "") return null;
 
@@ -479,6 +524,10 @@ export async function buildExportZip(
                 const ii = alloc.incominginvoice;
                 const vend = ii.vendor;
                 bookingLines.push(`${displayCurrency(alloc.amount,true)};"${shSelector}";;;;;${datevKonto};${vend?.vendorNumber};"";${formatDatevDate(ii.date, "DDMM")};"${ii.reference}";;;"${`ZA${alloc.description} ${bsText} `.substring(0,59)}";;;;;;;"Geschäftspartner";"${vend?.name}";"Kundennummer";"${vend?.vendorNumber}";"Belegnummer";"${ii.reference}";"Leistungsdatum";"${formatDatevDate(ii.date, "DD.MM.YYYY")}";"Belegdatum";"${dateFull}";;;;;;;;;;"";;;;;;;;Bank-Id;${alloc.bankstatement.id};;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;0;;;;"";;;;;;`);
+            }
+
+            if((alloc.createddocument && alloc.createddocument.customer) || (alloc.incominginvoice && alloc.incominginvoice.vendor)) {
+                bookingLines.push(...getCashDiscountBookingLines(alloc));
             } else if(alloc.account) {
                 bookingLines.push(getBankAccountBookingLine(alloc));
             } else if(alloc.vendor) {

backend/src/utils/gpt.ts

@@ -74,6 +74,9 @@ const InstructionFormat = z.object({
     tax: nullableNumber,
     total: nullableNumber,
     terms: nullableString,
+    cash_discount_percent: nullableNumber,
+    cash_discount_days: nullableNumber,
+    cash_discount_due_date: nullableString,
 });
 
 // ---------------------------------------------------------
@@ -190,6 +193,7 @@ export const getInvoiceDataFromGPT = async function (
                     "Do not merge summary totals into fabricated invoice_items.\n" +
                     "Match issuer by name to vendor.id.\n" +
                     "Match invoice items to account id based on label/number.\n" +
+                    "Set cash_discount_percent, cash_discount_days and cash_discount_due_date only when the invoice explicitly offers Skonto/cash discount (e.g. '2 % Skonto bei Zahlung innerhalb 10 Tagen'); otherwise null.\n" +
                     "Convert dates to YYYY-MM-DD.\n" +
                     "Keep invoice items in original order.\n",
             },

backend/src/utils/liquidityForecast.ts

@@ -685,14 +685,14 @@ export const generateLiquidityForecast = async (
         if (allocation.createddocument) {
             allocationByDocument.set(
                 allocation.createddocument,
-                roundMoney((allocationByDocument.get(allocation.createddocument) || 0) + Number(allocation.amount || 0))
+                roundMoney((allocationByDocument.get(allocation.createddocument) || 0) + Number(allocation.amount || 0) + Number(allocation.cashDiscountAmount || 0))
             );
         }
 
         if (allocation.incominginvoice) {
             allocationByIncomingInvoice.set(
                 allocation.incominginvoice,
-                roundMoney((allocationByIncomingInvoice.get(allocation.incominginvoice) || 0) + Number(allocation.amount || 0))
+                roundMoney((allocationByIncomingInvoice.get(allocation.incominginvoice) || 0) + Number(allocation.amount || 0) + Number(allocation.cashDiscountAmount || 0))
             );
         }
     });

backend/tests/cashDiscount.test.ts

@@ -0,0 +1,141 @@
+import assert from "node:assert/strict"
+import test from "node:test"
+import {
+    getCreatedDocumentGrossByRate,
+    getCreatedDocumentGrossTotal,
+    getIncomingInvoiceGrossByRate,
+    normalizeCashDiscountAccountsInput,
+    resolveCashDiscountAccounts,
+    splitCashDiscount,
+    validateCashDiscount,
+} from "../src/modules/cash-discount"
+import { getCashDiscountBookingLines } from "../src/utils/export/datev"
+import { prepareStatementAllocationInput } from "../src/mcp/statementAllocations"
+
+const defaults = resolveCashDiscountAccounts({})
+
+test("splits incoming invoice discount by tax rate onto received discount accounts", () => {
+    const gross = getIncomingInvoiceGrossByRate({
+        expense: true,
+        accounts: [
+            { taxType: "19", amountNet: 100, amountTax: 19 },
+            { taxType: "7", amountNet: 100, amountTax: 7 },
+        ],
+    })
+    assert.deepEqual(gross, { "19": -119, "7": -107, "0": 0 })
+
+    const split = splitCashDiscount(-4.52, gross, defaults.received)
+    assert.deepEqual(split, [
+        { rate: 19, account: "3736", gross: -2.38, net: -2, tax: -0.38 },
+        { rate: 7, account: "3731", gross: -2.14, net: -2, tax: -0.14 },
+    ])
+})
+
+test("assigns rounding differences to the largest share", () => {
+    const split = splitCashDiscount(1, { "19": 1, "7": 1, "0": 1 }, defaults.granted)
+    assert.equal(split.reduce((sum, item) => sum + item.gross, 0).toFixed(2), "1.00")
+    assert.equal(split.length, 3)
+})
+
+test("rejects discounts on intra-community acquisitions", () => {
+    assert.throws(
+        () => getIncomingInvoiceGrossByRate({ accounts: [{ taxType: "19I", amountNet: 100, amountTax: 0 }] }),
+        /manuell buchen/,
+    )
+})
+
+test("final invoices spread discounts over the remaining claim after advance invoices", () => {
+    const advance = { id: 7, rows: [{ advanceInvoiceData: true, price: 1000, taxPercent: 19 }] }
+    const final = {
+        id: 8,
+        usedAdvanceInvoices: [7],
+        rows: [
+            { mode: "normal", quantity: 1, price: 2000, discountPercent: 0, taxPercent: 19 },
+            { mode: "normal", quantity: 1, price: 1000, discountPercent: 0, taxPercent: 7 },
+        ],
+    }
+    assert.deepEqual(getCreatedDocumentGrossByRate(final, [advance]), { "19": 1190, "7": 1070, "0": 0 })
+    assert.equal(getCreatedDocumentGrossTotal(final, [advance]), 2260)
+})
+
+test("tax exempt small business invoices use the account without tax", () => {
+    const gross = getCreatedDocumentGrossByRate({
+        taxType: "19 UStG",
+        rows: [{ mode: "normal", quantity: 1, price: 100, discountPercent: 0, taxPercent: 19 }],
+    })
+    assert.deepEqual(gross, { "19": 0, "7": 0, "0": 100 })
+    assert.deepEqual(splitCashDiscount(2, gross, defaults.granted), [{ rate: 0, account: "8730", gross: 2, net: 2, tax: 0 }])
+})
+
+test("validates payment plus discount against the open amount", () => {
+    assert.doesNotThrow(() => validateCashDiscount({ amount: 98, discount: 2, total: 100, settled: 0 }))
+    assert.doesNotThrow(() => validateCashDiscount({ amount: -98, discount: -2, total: -100, settled: 0 }))
+    assert.throws(() => validateCashDiscount({ amount: 99, discount: 2, total: 100, settled: 0 }), /offenen Betrag/)
+    assert.throws(() => validateCashDiscount({ amount: 50, discount: 2, total: 100, settled: 50 }), /offenen Betrag/)
+    assert.throws(() => validateCashDiscount({ amount: 80, discount: 20, total: 100, settled: 0 }), /höher als 10 %/)
+    assert.throws(() => validateCashDiscount({ amount: -98, discount: -2, total: 100, settled: 0 }), /Richtung/)
+})
+
+test("normalizes configured discount accounts and keeps SKR03 defaults", () => {
+    const input = normalizeCashDiscountAccountsInput({ received: { "19": " 3737 ", "7": "" } })
+    assert.deepEqual(input, { received: { "19": "3737" } })
+    assert.equal(resolveCashDiscountAccounts(input).received["19"], "3737")
+    assert.equal(resolveCashDiscountAccounts(input).received["7"], "3731")
+    assert.throws(() => normalizeCashDiscountAccountsInput({ granted: { "19": "87A6" } }), /Ziffern/)
+})
+
+test("exports discount bookings per tax rate against the business partner", () => {
+    const lines = getCashDiscountBookingLines({
+        bankstatement: { id: 42, date: "2026-10-05" },
+        incominginvoice: { reference: "RE-1", vendor: { vendorNumber: "70001", name: "Lieferant" } },
+        cashDiscountSplit: [
+            { rate: 19, account: "3736", gross: -2.38, net: -2, tax: -0.38 },
+            { rate: 7, account: "3731", gross: -2.14, net: -2, tax: -0.14 },
+        ],
+    }).map(line => line.split(";"))
+
+    assert.equal(lines.length, 2)
+    assert.equal(lines[0].length, 124)
+    assert.deepEqual([lines[0][0], lines[0][1], lines[0][6], lines[0][7], lines[0][9], lines[0][10]],
+        ["2,38", '"H"', "3736", "70001", "0510", '"RE-1"'])
+
+    const [granted] = getCashDiscountBookingLines({
+        bankstatement: { id: 43, date: "2026-10-05" },
+        createddocument: { documentNumber: "RE-100", customer: { customerNumber: "10001", name: "Kunde" } },
+        cashDiscountSplit: [{ rate: 19, account: "8736", gross: 2.38, net: 2, tax: 0.38 }],
+    }).map(line => line.split(";"))
+    assert.deepEqual([granted[0], granted[1], granted[6], granted[7]], ["2,38", '"S"', "8736", "10001"])
+})
+
+test("MCP allocation input accepts cash discounts only with bank statements", () => {
+    const payload = prepareStatementAllocationInput({ bankstatement: 1, createddocument: 2, amount: 98, cashDiscountAmount: 2 })
+    assert.equal(payload.cashDiscountAmount, 2)
+    assert.throws(() => prepareStatementAllocationInput({
+        amount: 98, cashDiscountAmount: 2, manualBookingDate: "2026-10-01", account: 1, contraAccount: 2,
+    }), /Bankzahlung/)
+})
+
+test("builds cash discount terms and the PDF sentence", async () => {
+    const { appendCashDiscountText, buildCashDiscountTerms, formatCashDiscountText, getCashDiscountTemplateContext, parseCashDiscountPaymentTerms } = await import("../src/modules/cash-discount")
+    const terms = buildCashDiscountTerms({ percent: 2, days: 10, documentDate: "2026-11-04", amount: 1190 })
+    assert.deepEqual(terms, { percent: 2, days: 10, dueDate: "2026-11-14", discount: 23.8, payable: 1166.2 })
+    assert.equal(formatCashDiscountText(terms).replace(/ /g, " "),
+        "Bei Zahlung bis zum 14.11.2026 gewähren wir 2 % Skonto (23,80 €), Zahlbetrag 1.166,20 €.")
+    assert.equal(getCashDiscountTemplateContext(terms).skonto_datum, "14.11.2026")
+    assert.match(appendCashDiscountText("Vielen Dank.", "Vielen Dank.", terms), /^Bei Zahlung .*\n\nVielen Dank\.$/)
+    assert.equal(appendCashDiscountText("Eigener Text", "{{skonto_hinweis}}", terms), "Eigener Text")
+    assert.equal(buildCashDiscountTerms({ percent: null, days: 10, documentDate: "2026-11-04", amount: 100 }), null)
+
+    assert.deepEqual(parseCashDiscountPaymentTerms("#SKONTO#TAGE=7#PROZENT=3.00#\n#SKONTO#TAGE=14#PROZENT=2.00#"), { percent: 3, days: 7 })
+    assert.deepEqual(parseCashDiscountPaymentTerms("#SKONTO#TAGE=14#PROZENT=2,5#BASISBETRAG=100.00#"), { percent: 2.5, days: 14 })
+    assert.equal(parseCashDiscountPaymentTerms("Zahlbar ohne Abzug"), null)
+})
+
+test("maps explicit AI cash discount data onto incoming invoices", async () => {
+    const { mapGptDataToIncomingInvoice } = await import("../src/modules/cron/prepareIncomingInvoices")
+    const mapped = mapGptDataToIncomingInvoice({ invoice_date: "2026-11-01", cash_discount_percent: 2, cash_discount_days: 10 }, 1)
+    assert.equal(mapped.cashDiscountPercent, 2)
+    assert.equal(mapped.cashDiscountDueDate, "2026-11-11")
+    const ignored = mapGptDataToIncomingInvoice({ invoice_date: "2026-11-01", cash_discount_percent: 25 }, 1)
+    assert.equal(ignored.cashDiscountPercent, undefined)
+})

backend/tests/einvoice.test.ts

@@ -66,3 +66,27 @@ test("markiert Summenabweichungen als Prüfungsfehler", () => {
 
     assert.match(parsed.validation.errors.join(" "), /Positionssumme/)
 })
+
+test("reads XRechnung cash discount terms from CII payment terms", async () => {
+    const xml = Buffer.from(ciiInvoice.toString().replace(
+        "<ram:SpecifiedTradePaymentTerms>",
+        "<ram:SpecifiedTradePaymentTerms><ram:Description>#SKONTO#TAGE=10#PROZENT=2.00#\n</ram:Description>",
+    ))
+    const detection = await detectElectronicInvoice(xml, { name: "rechnung.xml" })
+    const parsed = parseElectronicInvoice(detection!.xml, detection!.syntax)
+    assert.deepEqual(parsed.cashDiscount, { percent: 2, days: 10 })
+
+    const mapped = mapElectronicInvoiceToIncomingInvoice(parsed, 1, 5, "xml", null)
+    assert.equal(mapped.cashDiscountPercent, 2)
+    assert.equal(mapped.cashDiscountDueDate, "2026-07-31")
+})
+
+test("reads cash discount terms from UBL payment terms notes", async () => {
+    const xml = Buffer.from(ublInvoice.toString().replace(
+        "<cac:PaymentMeans>",
+        "<cac:PaymentTerms><cbc:Note>#SKONTO#TAGE=14#PROZENT=3.00#</cbc:Note></cac:PaymentTerms><cac:PaymentMeans>",
+    ))
+    const detection = await detectElectronicInvoice(xml, { name: "xrechnung.xml" })
+    const parsed = parseElectronicInvoice(detection!.xml, detection!.syntax)
+    assert.deepEqual(parsed.cashDiscount, { percent: 3, days: 14 })
+})

backend/tests/zugferdInvoice.test.ts

@@ -0,0 +1,209 @@
+import assert from "node:assert/strict"
+import test from "node:test"
+import { PDFDocument, StandardFonts } from "pdf-lib"
+import { buildZugferdInvoiceXml, checkZugferdRequirements, countryCode, unitCode, ZugferdInvoiceContext } from "../src/modules/einvoice/buildZugferdInvoice"
+import { embedZugferdXml } from "../src/modules/einvoice/embedZugferd"
+import { detectElectronicInvoice } from "../src/modules/einvoice/detectElectronicInvoice"
+import { parseElectronicInvoice } from "../src/modules/einvoice/parseElectronicInvoice"
+
+const context = (overrides: Partial<ZugferdInvoiceContext> = {}): ZugferdInvoiceContext => ({
+    tenant: {
+        name: "Muster GmbH",
+        creditorId: "DE98ZZZ09999999999",
+        businessInfo: {
+            name: "Muster GmbH", street: "Hauptstraße 1", zip: "12345", city: "Musterstadt",
+            vatId: "DE123456789", taxNumber: "12/345/67890", email: "rechnung@muster.de",
+            iban: "DE02120300000000202051", bic: "BYLADEM1001", bankAccountOwner: "Muster GmbH",
+        },
+    },
+    customer: {
+        name: "Kunde & Söhne KG", customerNumber: "10001",
+        infoData: { street: "Kundenweg 5", zip: "54321", city: "Kundenstadt", country: "Deutschland", ustid: "DE987654321", invoiceEmail: "buchhaltung@kunde.de" },
+    },
+    contactPerson: { full_name: "Erika Muster", email: "erika@muster.de" },
+    units: [{ id: 1, short: "Stk" }, { id: 6, short: "Std" }],
+    products: [{ id: 7, name: "Kabel NYM 3x1,5", article_number: "A-7" }],
+    services: [{ id: 3, name: "Montage" }],
+    bankAccounts: [],
+    advanceInvoices: [],
+    ...overrides,
+})
+
+const invoice = (overrides: any = {}) => ({
+    id: 1,
+    type: "invoices",
+    customer: 5,
+    documentNumber: "RE-2026-0042",
+    documentDate: "2026-11-04",
+    deliveryDateType: "Lieferdatum",
+    deliveryDate: "2026-11-02",
+    paymentDays: 14,
+    payment_type: "transfer",
+    taxType: "Standard",
+    title: "Rechnung-Nr. RE-2026-0042",
+    address: { street: "Kundenweg 5", zip: "54321", city: "Kundenstadt" },
+    rows: [
+        { pos: "1", mode: "normal", product: 7, quantity: 10, unit: 1, price: 2.345, discountPercent: 0, taxPercent: 19 },
+        { pos: "2", mode: "service", service: 3, quantity: 1.5, unit: 6, price: 60, discountPercent: 10, taxPercent: 19 },
+        { pos: "3", mode: "free", text: "Fachbuch", quantity: 1, unit: 1, price: 20, discountPercent: 0, taxPercent: 7 },
+        { mode: "title", text: "Optionales" },
+        { pos: "4", mode: "free", text: "Optional", quantity: 1, unit: 1, price: 999, discountPercent: 0, taxPercent: 19, optional: true },
+        { pos: "5", mode: "free", text: "Gutschrift Altmaterial", quantity: 1, unit: 1, price: -5, discountPercent: 0, taxPercent: 19 },
+    ],
+    ...overrides,
+})
+
+const tag = (xml: string, name: string) => [...xml.matchAll(new RegExp(`<ram:${name}(?:\\s[^>]*)?>([^<]*)</ram:${name}>`, "g"))].map((match) => match[1])
+
+test("erzeugt eine EN-16931-Rechnung mit konsistenten Summen", () => {
+    const { xml, issues, totals } = buildZugferdInvoiceXml(invoice(), context())
+
+    assert.deepEqual(issues, [])
+    // 23,45 + 81,00 + 20,00 - 5,00 (optionale Position ausgeschlossen)
+    assert.equal(totals.lineNet, 119.45)
+    // 19 %: 99,45 -> 18,90; 7 %: 20,00 -> 1,40
+    assert.equal(totals.tax, 20.3)
+    assert.equal(totals.gross, 139.75)
+    assert.equal(totals.payable, 139.75)
+    assert.match(xml, /<ram:ID>urn:cen.eu:en16931:2017<\/ram:ID>/)
+    assert.match(xml, /<ram:TypeCode>380<\/ram:TypeCode>/)
+    assert.match(xml, /Kunde &amp; Söhne KG/)
+    assert.match(xml, /<ram:IBANID>DE02120300000000202051<\/ram:IBANID>/)
+    assert.match(xml, /<ram:ID schemeID="VA">DE987654321<\/ram:ID>/)
+    assert.match(xml, /<ram:SellerAssignedID>A-7<\/ram:SellerAssignedID>/)
+    assert.match(xml, /<ram:DueDateDateTime><udt:DateTimeString format="102">20261118<\/udt:DateTimeString>/)
+    assert.match(xml, /<ram:OccurrenceDateTime><udt:DateTimeString format="102">20261102/)
+    // Negative Preise werden als negative Menge mit positivem Nettopreis abgebildet (BR-27).
+    assert.match(xml, /<ram:ChargeAmount>5<\/ram:ChargeAmount><\/ram:NetPriceProductTradePrice><\/ram:SpecifiedLineTradeAgreement><ram:SpecifiedLineTradeDelivery><ram:BilledQuantity unitCode="H87">-1</)
+    assert.ok(tag(xml, "ChargeAmount").every((value) => Number(value) >= 0))
+    // vier Positionen plus zwei Steuergruppen (19 % und 7 %)
+    assert.deepEqual(tag(xml, "CategoryCode"), ["S", "S", "S", "S", "S", "S"])
+    assert.deepEqual(tag(xml, "RateApplicablePercent").slice(-2), ["19", "7"])
+})
+
+test("das eigene XML wird vom FEDEO-Parser ohne Fehler gelesen", async () => {
+    const { xml } = buildZugferdInvoiceXml(invoice(), context())
+    const parsed = parseElectronicInvoice(Buffer.from(xml), "cii")
+
+    assert.deepEqual(parsed.validation.errors, [])
+    assert.equal(parsed.invoiceNumber, "RE-2026-0042")
+    assert.equal(parsed.seller.vatId, "DE123456789")
+    assert.equal(parsed.totals.gross, 139.75)
+    assert.equal(parsed.items.length, 4)
+})
+
+test("bettet das XML als factur-x.xml in die PDF ein", async () => {
+    const source = await PDFDocument.create()
+    const page = source.addPage()
+    page.drawText("Rechnung", { font: await source.embedFont(StandardFonts.Helvetica), x: 50, y: 700 })
+    const { xml } = buildZugferdInvoiceXml(invoice(), context())
+
+    const pdf = await embedZugferdXml(await source.save(), xml, { title: "Rechnung RE-2026-0042" })
+    const detection = await detectElectronicInvoice(pdf, { name: "RE-2026-0042.pdf", mimeType: "application/pdf" })
+
+    assert.equal(detection?.container, "pdf")
+    assert.equal(detection?.syntax, "cii")
+    assert.equal(detection?.attachmentName, "factur-x.xml")
+    assert.equal(detection?.xml.toString("utf8"), xml)
+    const raw = pdf.toString("latin1")
+    assert.match(raw, /\/AFRelationship \/Alternative/)
+    assert.match(raw, /<fx:ConformanceLevel>EN 16931<\/fx:ConformanceLevel>/)
+    assert.equal((await PDFDocument.load(pdf)).getPageCount(), 1)
+})
+
+test("Stornorechnung wird als Gutschrift mit positiven Beträgen und Bezug zur Rechnung ausgegeben", () => {
+    const { xml, totals } = buildZugferdInvoiceXml(invoice({
+        type: "cancellationInvoices",
+        documentNumber: "RE-2026-0043",
+        rows: [{ pos: "1", mode: "free", text: "Montage", quantity: 2, unit: 6, price: -50, discountPercent: 0, taxPercent: 19 }],
+    }), context({ linkedDocument: { documentNumber: "RE-2026-0042", documentDate: "2026-11-04" } }))
+
+    assert.match(xml, /<ram:TypeCode>381<\/ram:TypeCode>/)
+    assert.equal(totals.gross, 119)
+    assert.match(xml, /<ram:BilledQuantity unitCode="HUR">2<\/ram:BilledQuantity>/)
+    assert.match(xml, /<ram:InvoiceReferencedDocument><ram:IssuerAssignedID>RE-2026-0042<\/ram:IssuerAssignedID>/)
+})
+
+test("Schlussrechnung zieht Abschläge als bereits gezahlten Betrag ab", () => {
+    const { xml, totals } = buildZugferdInvoiceXml(invoice({
+        rows: [{ pos: "1", mode: "free", text: "Gesamtleistung", quantity: 1, unit: 1, price: 1000, discountPercent: 0, taxPercent: 19 }],
+    }), context({ advanceInvoices: [{ rows: [{ advanceInvoiceData: {}, price: 500, taxPercent: 19 }] }] }))
+
+    assert.equal(totals.gross, 1190)
+    assert.equal(totals.prepaid, 595)
+    assert.equal(totals.payable, 595)
+    assert.match(xml, /<ram:TotalPrepaidAmount>595.00<\/ram:TotalPrepaidAmount><ram:DuePayableAmount>595.00<\/ram:DuePayableAmount>/)
+})
+
+test("§ 13b und Kleinunternehmer verwenden die passenden Steuerkategorien", () => {
+    const reverseCharge = buildZugferdInvoiceXml(invoice({ taxType: "13b UStG", rows: [{ pos: "1", mode: "free", text: "Bauleistung", quantity: 1, unit: 1, price: 100, taxPercent: 0 }] }), context())
+    assert.match(reverseCharge.xml, /<ram:CategoryCode>AE<\/ram:CategoryCode><ram:ExemptionReasonCode>VATEX-EU-AE<\/ram:ExemptionReasonCode>/)
+    assert.equal(reverseCharge.totals.tax, 0)
+
+    const smallBusiness = buildZugferdInvoiceXml(invoice({ taxType: "19 UStG", rows: [{ pos: "1", mode: "free", text: "Beratung", quantity: 1, unit: 1, price: 100, taxPercent: 0 }] }), context())
+    assert.match(smallBusiness.xml, /<ram:ExemptionReason>Kein Ausweis von Umsatzsteuer, da Kleinunternehmer gemäß § 19 UStG<\/ram:ExemptionReason>/)
+    assert.match(smallBusiness.xml, /<ram:CategoryCode>E<\/ram:CategoryCode>/)
+})
+
+test("Leistungszeitraum, Lastschrift und Skonto werden strukturiert übertragen", () => {
+    const { xml, issues } = buildZugferdInvoiceXml(invoice({
+        deliveryDateType: "Leistungszeitraum", deliveryDate: "2026-10-01", deliveryDateEnd: "2026-10-31",
+        payment_type: "direct-debit", cashDiscountPercent: 2, cashDiscountDays: 7,
+    }), context({ sepaMandate: { reference: "MANDAT-1" } }))
+
+    assert.deepEqual(issues, [])
+    assert.match(xml, /<ram:BillingSpecifiedPeriod><ram:StartDateTime><udt:DateTimeString format="102">20261001/)
+    assert.match(xml, /<ram:CreditorReferenceID>DE98ZZZ09999999999<\/ram:CreditorReferenceID>/)
+    assert.match(xml, /<ram:TypeCode>59<\/ram:TypeCode>/)
+    assert.match(xml, /<ram:DirectDebitMandateID>MANDAT-1<\/ram:DirectDebitMandateID>/)
+    assert.match(xml, /#SKONTO#TAGE=7#PROZENT=2.00#BASISBETRAG=139.75#/)
+    assert.doesNotMatch(xml, /ActualDeliverySupplyChainEvent/)
+})
+
+test("ordnet Länder und Einheiten den Codelisten zu", () => {
+    assert.equal(countryCode("Österreich"), "AT")
+    assert.equal(countryCode(""), "DE")
+    assert.equal(countryCode("ch"), "CH")
+    assert.equal(unitCode({ short: "Std" }), "HUR")
+    assert.equal(unitCode({ short: "m²" }), "MTK")
+    assert.equal(unitCode({ short: "unbekannt" }), "C62")
+})
+
+const breakingMessages = (document: any, ctx: ZugferdInvoiceContext, requireNumber = false) =>
+    checkZugferdRequirements(document, ctx, { requireNumber }).filter((issue) => issue.type === "breaking").map((issue) => issue.message)
+
+test("Pflichtangaben: vollständiger Beleg hat keine blockierenden Fehler", () => {
+    assert.deepEqual(breakingMessages(invoice(), context(), true), [])
+    assert.deepEqual(breakingMessages(invoice({ documentNumber: null }), context()), [])
+    assert.deepEqual(breakingMessages(invoice({ documentNumber: null }), context(), true), ["E-Rechnung: Die Rechnungsnummer fehlt"])
+})
+
+test("Pflichtangaben: fehlende Firmendaten, Kundenanschrift und IBAN blockieren", () => {
+    const ctx = context({
+        tenant: { businessInfo: { name: "Muster GmbH", street: "", zip: "12345", city: "Musterstadt" } },
+    })
+    const messages = breakingMessages(invoice({ address: { street: "Kundenweg 5", zip: "", city: "Kundenstadt" } }), ctx)
+
+    assert.ok(messages.some((message) => message.includes("Firmenanschrift")))
+    assert.ok(messages.some((message) => message.includes("weder eine USt-IdNr. noch eine Steuernummer")))
+    assert.ok(messages.some((message) => message.includes("Anschrift des Kunden")))
+    assert.ok(messages.some((message) => message.includes("keine IBAN")))
+    // Ein Bankkonto mit IBAN genügt anstelle der IBAN in den Firmendaten
+    const withAccount = context({ bankAccounts: [{ iban: "DE02120300000000202051" }] })
+    withAccount.tenant.businessInfo.iban = ""
+    assert.deepEqual(breakingMessages(invoice(), withAccount), [])
+})
+
+test("Pflichtangaben: § 13b und Lastschrift verlangen ihre Zusatzangaben", () => {
+    const reverseCharge = breakingMessages(invoice({ taxType: "13b UStG" }), context({ customer: { name: "Bau AG", infoData: {} } }))
+    assert.deepEqual(reverseCharge, ["E-Rechnung: Für § 13b UStG muss beim Kunden eine USt-Id hinterlegt sein"])
+
+    const directDebit = breakingMessages(invoice({ payment_type: "direct-debit" }), context({ tenant: { ...context().tenant, creditorId: "" } }))
+    assert.deepEqual(directDebit, [
+        "E-Rechnung: Für SEPA-Lastschrift ist in den Firmendaten keine Gläubiger-ID hinterlegt",
+        "E-Rechnung: Für SEPA-Lastschrift ist kein Mandat mit Mandatsreferenz ausgewählt",
+    ])
+
+    const noDate = checkZugferdRequirements(invoice({ deliveryDateType: "Kein Lieferdatum anzeigen" }), context())
+    assert.deepEqual(noDate.map((issue) => issue.type), ["info"])
+})

docs-site/content/bedienung/bankportal.md

@@ -36,6 +36,23 @@ Vor dem Buchen werden Netto-, Steuer- und Bruttobetrag angezeigt. Beispielsweise
 
 Der DATEV-Export übergibt den Bruttobetrag mit dem gewählten BU-Schlüssel (9/8 für Vorsteuer, 3/2 für Umsatzsteuer) und die Kostenstellennummer in **KOST1**. „Ohne Umsatzsteuer“ verwendet Schlüssel 40, um auch eine Kontenautomatik aufzuheben. Bestehende Buchungen ohne Steuerauswahl werden nicht nachträglich umgerechnet. Die Zuordnung folgt den [DATEV-Steuerschlüsseln](https://www.datev.de/dnlexom/v2/content/files/st2286167563_de.pdf) und der [DATEV-Dokumentation zur Aufhebung der Automatik](https://apps.datev.de/help-center/api/knowledge-help/v1/content/entities/st2112778507_de.pdf?docId=0907888&save=False).
 
+## Zahlung mit Skonto ausgleichen
+
+Zahlt ein Kunde weniger als den offenen Betrag oder ziehst du bei einem Lieferanten Skonto ab, öffne den Bankumsatz und wähle beim Beleg **Mit Skonto ausgleichen** (Prozent-Symbol). Der Vorschlag ist die Differenz zwischen offenem Betrag und Zahlung. Zahlung und Skonto gleichen den Beleg gemeinsam aus; der Bankumsatz enthält weiterhin nur den gezahlten Betrag.
+
+- Der Skonto wird anteilig nach den Steuersätzen des Belegs verteilt und mindert die Umsatzsteuer (Ausgangsbelege) bzw. Vorsteuer (Eingangsbelege) im Zeitraum der Zahlung.
+- Bei Schlussrechnungen bleiben die Abschläge mit ihren ursprünglich berechneten Beträgen abgezogen. Skonto auf eine Abschlagsrechnung wird bei deren Zahlung gebucht, Skonto auf die Schlussrechnung bezieht sich auf die Restforderung.
+- Der DATEV-Export erzeugt je Steuersatz eine eigene Buchung vom Skontokonto gegen Debitor bzw. Kreditor mit der Rechnungsnummer als Belegfeld.
+- Standard sind die SKR-03-Automatikkonten 3736/3731/3730 (erhaltene Skonti) und 8736/8731/8730 (gewährte Skonti). Abweichende Konten trägst du unter **Firmeneinstellungen → Rechnung & Kontakt → Skontokonten** ein.
+- Skonto über 10 % des Belegs, auf Belege nach §13b UStG oder mit innergemeinschaftlichem Erwerb wird abgelehnt und muss manuell gebucht werden.
+- Wird die Bankzuordnung gelöscht, entfällt auch der Skonto.
+
+### Skontobedingungen auf Belegen
+
+- **Ausgangsbelege:** Im Beleg-Editor Skontosatz und Frist in Tagen eintragen. Kunden können unter *Skonto in %* und *Skontofrist in Tagen* eine Vorgabe haben, die bei der Kundenauswahl übernommen wird. Im PDF steht automatisch ein Satz wie „Bei Zahlung bis zum 14.11.2026 gewähren wir 2 % Skonto (23,80 €), Zahlbetrag 1.166,20 €.“ vor dem Endtext. Wer den Satz selbst formulieren will, nutzt in der Textvorlage `{{skonto_hinweis}}`, `{{skonto_prozent}}`, `{{skonto_datum}}`, `{{skonto_betrag}}` oder `{{zahlbetrag_mit_skonto}}`; dann entfällt der automatische Satz. Bei Schlussrechnungen bezieht sich der Skonto auf die Restforderung nach Abzug der Abschläge.
+- **Eingangsbelege:** Skontosatz und letzter Skontotag werden aus E-Rechnungen (`#SKONTO#TAGE=…#PROZENT=…#` bzw. ZUGFeRD-Skontobedingungen) und, wenn ausdrücklich genannt, von der KI-Vorbereitung übernommen. Lieferanten können eine Vorgabe haben, die bei der Lieferantenauswahl eingesetzt wird.
+- **Vorschläge:** Entspricht eine Zahlung dem offenen Betrag abzüglich des vereinbarten Skontos und liegt sie in der Frist, zeigt die Bankzuordnung „Passt mit 2 % Skonto“. In der Vorschlagsübersicht lässt sich die Zahlung dann direkt mit Skonto zuweisen.
+
 ## Gute Praxis
 
 - Regelmäßig abrufen, damit sich keine großen Rückstände bilden.

docs/bedienung/bankportal.md

@@ -36,6 +36,23 @@ Vor dem Buchen werden Netto-, Steuer- und Bruttobetrag angezeigt. Beispielsweise
 
 Der DATEV-Export übergibt den Bruttobetrag mit dem gewählten BU-Schlüssel (9/8 für Vorsteuer, 3/2 für Umsatzsteuer) und die Kostenstellennummer in **KOST1**. „Ohne Umsatzsteuer“ verwendet Schlüssel 40, um auch eine Kontenautomatik aufzuheben. Bestehende Buchungen ohne Steuerauswahl werden nicht nachträglich umgerechnet. Die Zuordnung folgt den [DATEV-Steuerschlüsseln](https://www.datev.de/dnlexom/v2/content/files/st2286167563_de.pdf) und der [DATEV-Dokumentation zur Aufhebung der Automatik](https://apps.datev.de/help-center/api/knowledge-help/v1/content/entities/st2112778507_de.pdf?docId=0907888&save=False).
 
+## Zahlung mit Skonto ausgleichen
+
+Zahlt ein Kunde weniger als den offenen Betrag oder ziehst du bei einem Lieferanten Skonto ab, öffne den Bankumsatz und wähle beim Beleg **Mit Skonto ausgleichen** (Prozent-Symbol). Der Vorschlag ist die Differenz zwischen offenem Betrag und Zahlung. Zahlung und Skonto gleichen den Beleg gemeinsam aus; der Bankumsatz enthält weiterhin nur den gezahlten Betrag.
+
+- Der Skonto wird anteilig nach den Steuersätzen des Belegs verteilt und mindert die Umsatzsteuer (Ausgangsbelege) bzw. Vorsteuer (Eingangsbelege) im Zeitraum der Zahlung.
+- Bei Schlussrechnungen bleiben die Abschläge mit ihren ursprünglich berechneten Beträgen abgezogen. Skonto auf eine Abschlagsrechnung wird bei deren Zahlung gebucht, Skonto auf die Schlussrechnung bezieht sich auf die Restforderung.
+- Der DATEV-Export erzeugt je Steuersatz eine eigene Buchung vom Skontokonto gegen Debitor bzw. Kreditor mit der Rechnungsnummer als Belegfeld.
+- Standard sind die SKR-03-Automatikkonten 3736/3731/3730 (erhaltene Skonti) und 8736/8731/8730 (gewährte Skonti). Abweichende Konten trägst du unter **Firmeneinstellungen → Rechnung & Kontakt → Skontokonten** ein.
+- Skonto über 10 % des Belegs, auf Belege nach §13b UStG oder mit innergemeinschaftlichem Erwerb wird abgelehnt und muss manuell gebucht werden.
+- Wird die Bankzuordnung gelöscht, entfällt auch der Skonto.
+
+### Skontobedingungen auf Belegen
+
+- **Ausgangsbelege:** Im Beleg-Editor Skontosatz und Frist in Tagen eintragen. Kunden können unter *Skonto in %* und *Skontofrist in Tagen* eine Vorgabe haben, die bei der Kundenauswahl übernommen wird. Im PDF steht automatisch ein Satz wie „Bei Zahlung bis zum 14.11.2026 gewähren wir 2 % Skonto (23,80 €), Zahlbetrag 1.166,20 €.“ vor dem Endtext. Wer den Satz selbst formulieren will, nutzt in der Textvorlage `{{skonto_hinweis}}`, `{{skonto_prozent}}`, `{{skonto_datum}}`, `{{skonto_betrag}}` oder `{{zahlbetrag_mit_skonto}}`; dann entfällt der automatische Satz. Bei Schlussrechnungen bezieht sich der Skonto auf die Restforderung nach Abzug der Abschläge.
+- **Eingangsbelege:** Skontosatz und letzter Skontotag werden aus E-Rechnungen (`#SKONTO#TAGE=…#PROZENT=…#` bzw. ZUGFeRD-Skontobedingungen) und, wenn ausdrücklich genannt, von der KI-Vorbereitung übernommen. Lieferanten können eine Vorgabe haben, die bei der Lieferantenauswahl eingesetzt wird.
+- **Vorschläge:** Entspricht eine Zahlung dem offenen Betrag abzüglich des vereinbarten Skontos und liegt sie in der Frist, zeigt die Bankzuordnung „Passt mit 2 % Skonto“. In der Vorschlagsübersicht lässt sich die Zahlung dann direkt mit Skonto zuweisen.
+
 ## Gute Praxis
 
 - Regelmäßig abrufen, damit sich keine großen Rückstände bilden.

frontend/components/displayBWASummary.vue

@@ -1,6 +1,7 @@
 <script setup lang="ts">
 import dayjs from "dayjs"
 import { getBankAllocationTaxBreakdown } from "~/utils/bankAllocationTax"
+import { getCashDiscountNetTotals } from "~/utils/cashDiscount"
 import {
   getCreatedDocumentTaxBreakdown,
   getIncomingInvoiceTaxBreakdown
@@ -90,7 +91,7 @@ const loadSummary = async () => {
       return touchesAccount && date.isValid() && !date.isBefore(bounds.start, "day") && !date.isAfter(bounds.end, "day")
     })
 
-    const income = outputDocs.reduce((sum: number, doc: any) => {
+    const documentIncome = outputDocs.reduce((sum: number, doc: any) => {
       return sum + (doc.rows || []).reduce((rowSum: number, row: any) => {
         if (!row || ["pagebreak", "title", "text"].includes(row.mode)) {
           return rowSum
@@ -132,7 +133,14 @@ const loadSummary = async () => {
       const { output, input } = getBankAllocationTaxBreakdown(allocation)
       return sum + output.tax19 + output.tax7 - input.tax19 - input.tax7
     }, 0)
-    const expenses = invoiceExpenses + directAccountExpenses + depreciations
+    // Skonto wirkt im Monat der Zahlung auf Erlöse und Aufwand.
+    const cashDiscountTotals = getCashDiscountNetTotals((allocations || []).filter((allocation: any) => {
+      const date = dayjs(allocation.bankstatement?.date || allocation.bankstatement?.valueDate)
+      return date.isValid() && !date.isBefore(bounds.start, "day") && !date.isAfter(bounds.end, "day")
+    }))
+    const expenses = invoiceExpenses + directAccountExpenses + depreciations - cashDiscountTotals.receivedNet
+
+    const income = documentIncome - cashDiscountTotals.grantedNet
 
     summary.value = {
       label: dayjs().format("MMMM YYYY"),

frontend/composables/useFunctions.js

@@ -34,15 +34,19 @@ export const useFunctions = () => {
         return (await useNuxtApp().$api(`/api/banking/link/${institutionId}`)).link
     }
 
-    const useCreatePDF = async (data,path,type) => {
+    // options.createdDocumentId: gespeicherter Beleg, aus dem das Backend die eingebettete E-Rechnung (ZUGFeRD) erzeugt
+    const useCreatePDF = async (data,path,type,options = {}) => {
         const returnData = await useNuxtApp().$api(`/api/functions/pdf/${type}`, {
             method: "POST",
             body: {
                 data: data,
                 backgroundPath: path,
+                ...(options.createdDocumentId ? { createdDocumentId: options.createdDocumentId } : {}),
             }
         })
 
+        if (options.onResult) options.onResult(returnData)
+
         console.log(returnData)
 
         return `data:${returnData.mimeType};base64,${returnData.base64}`

frontend/composables/useSum.js

@@ -1,3 +1,4 @@
+import { sumSettledAllocations } from "~/utils/cashDiscount"
 
 export const useSum = () => {
     const unwrapCreatedDocuments = (createddocuments = []) => {
@@ -83,8 +84,8 @@ export const useSum = () => {
     }
 
     const getCreatedDocumentOpenAmount = (createddocument, createddocuments = []) => {
-        let amountPaid = 0
+        // Gebuchter Skonto gleicht den Beleg zusammen mit der Zahlung aus.
-        createddocument.statementallocations.forEach(allocation => amountPaid += allocation.amount)
+        const amountPaid = sumSettledAllocations(createddocument.statementallocations || [])
 
         return Number((getCreatedDocumentSum(createddocument, createddocuments) - amountPaid).toFixed(2))
     }

frontend/pages/accounting/bwa.vue

@@ -1,4 +1,5 @@
 <script setup lang="ts">
+import { getCashDiscountNetTotals } from "~/utils/cashDiscount"
 import dayjs from "dayjs"
 import { getBankAllocationAmounts, getBankAllocationTaxBreakdown } from "~/utils/bankAllocationTax"
 import {
@@ -183,8 +184,12 @@ const selectedPeriodBounds = computed(() => {
   return { start, end }
 })
 
+// Skonto wirkt im Zeitraum der Zahlung: gewährter Skonto mindert Erlöse, erhaltener Skonto den Aufwand.
+const cashDiscountTotals = computed(() => getCashDiscountNetTotals(filteredStatementAllocations.value))
+
 const incomeTotal = computed(() => {
-  return Number(filteredDocuments.value.reduce((sum, doc) => sum + computeDocumentNet(doc), 0).toFixed(2))
+  const documents = filteredDocuments.value.reduce((sum, doc) => sum + computeDocumentNet(doc), 0)
+  return Number((documents - cashDiscountTotals.value.grantedNet).toFixed(2))
 })
 
 const expenseNetTotal = computed(() => {
@@ -196,7 +201,7 @@ const expenseNetTotal = computed(() => {
 
   const depreciations = depreciationTotal.value
 
-  return Number((invoiceExpenses + directAccountExpenses + depreciations).toFixed(2))
+  return Number((invoiceExpenses + directAccountExpenses + depreciations - cashDiscountTotals.value.receivedNet).toFixed(2))
 })
 
 const expenseGrossTotal = computed(() => {
@@ -206,7 +211,7 @@ const expenseGrossTotal = computed(() => {
 
   const depreciations = depreciationTotal.value
 
-  return Number((invoiceExpenses + directAccountExpenses + depreciations).toFixed(2))
+  return Number((invoiceExpenses + directAccountExpenses + depreciations - cashDiscountTotals.value.receivedGross).toFixed(2))
 })
 
 const taxSummary = computed(() => {

frontend/pages/accounting/tax.vue

@@ -1,6 +1,7 @@
 <script setup lang="ts">
 import dayjs from "dayjs"
 import { getBankAllocationTaxBreakdown, isDirectBankAllocation } from "~/utils/bankAllocationTax"
+import { hasCashDiscount } from "~/utils/cashDiscount"
 import customParseFormat from "dayjs/plugin/customParseFormat"
 import {
   formatTaxEvaluationPeriodLabel,
@@ -54,7 +55,7 @@ const loadData = async () => {
     createdDocuments.value = (docs || []).filter(isRelevantOutputDocument)
     incomingInvoices.value = (incoming || []).filter(isRelevantInputInvoice)
     manualBookings.value = (manual as any[]) || []
-    bankAllocations.value = (allocations || []).filter(isDirectBankAllocation)
+    bankAllocations.value = (allocations || []).filter((allocation) => isDirectBankAllocation(allocation) || hasCashDiscount(allocation))
   } finally {
     loading.value = false
   }

frontend/pages/banking/index.vue

@@ -1,4 +1,5 @@
 <script setup>
+import { matchCashDiscountPayment, sumSettledAllocations } from "~/utils/cashDiscount"
 import { parseDate } from "@internationalized/date"
 
 const {$api, $dayjs} = useNuxtApp()
@@ -103,12 +104,12 @@ const loadSuggestionData = async () => {
         .map(i => ({
           ...i,
           docTotal: useSum().getCreatedDocumentSum(i, createddocuments.value),
-          statementTotal: Number(i.statementallocations.reduce((n, {amount}) => n + amount, 0)),
+          statementTotal: Number(sumSettledAllocations(i.statementallocations)),
           openSum: useSum().getCreatedDocumentOpenAmount(i, createddocuments.value).toFixed(2)
         }))
 
     openIncomingInvoices.value = invoiceItems
-        .filter(i => i.state === "Gebucht" && !i.archived && i.statementallocations.reduce((n, {amount}) => n + amount, 0).toFixed(2) !== getInvoiceSum(i, false))
+        .filter(i => i.state === "Gebucht" && !i.archived && sumSettledAllocations(i.statementallocations).toFixed(2) !== getInvoiceSum(i, false))
   } catch (err) {
     console.error("Vorschlagsdaten konnten nicht geladen werden:", err)
   } finally {
@@ -232,7 +233,7 @@ const calculateOpenSum = (statement) => {
 const getInvoiceSum = (invoice, onlyOpenSum) => {
   let sum = Number(useSum().getIncomingInvoiceSum(invoice))
 
-  if (onlyOpenSum) sum = sum + Number(invoice.statementallocations.reduce((n, {amount}) => n + amount, 0))
+  if (onlyOpenSum) sum = sum + Number(sumSettledAllocations(invoice.statementallocations))
 
   if (invoice.expense) {
     return (sum * -1).toFixed(2)
@@ -386,25 +387,52 @@ const getTopEntitySuggestion = (statement) => {
   return suggestions[0] || null
 }
 
+// Zahlung entspricht dem offenen Betrag abzüglich vereinbartem Skonto und liegt in der Frist.
+const getCashDiscountMatch = (statement, kind, entity) => {
+  const paymentDate = getStatementDate(statement) ? $dayjs(getStatementDate(statement)).format("YYYY-MM-DD") : null
+  if (kind === "createddocument") {
+    const days = entity.cashDiscountDays
+    return matchCashDiscountPayment({
+      open: entity.openSum,
+      payment: calculateOpenSum(statement),
+      percent: entity.cashDiscountPercent,
+      dueDate: entity.documentDate && days !== null && days !== undefined && days !== ""
+          ? $dayjs(entity.documentDate).add(Number(days), "day").format("YYYY-MM-DD")
+          : null,
+      paymentDate
+    })
+  }
+  return matchCashDiscountPayment({
+    open: getInvoiceSum(entity, true),
+    payment: calculateOpenSum(statement),
+    percent: entity.cashDiscountPercent,
+    dueDate: entity.cashDiscountDueDate || null,
+    paymentDate
+  })
+}
+
 const getDocumentSuggestionMeta = (statement, document, suggestion) => {
   let score = 0
   const remaining = Math.abs(Number(calculateOpenSum(statement)))
   const openSum = Math.abs(Number(document.openSum))
   const purposeMatches = getMatchingPurposeParts(statement.text, [document.documentNumber, document.title, document.description])
-  const amountLabel = getAmountMatchLabel(openSum, remaining)
+  const cashDiscountMatch = getCashDiscountMatch(statement, "createddocument", document)
-  const withinTolerance = isWithinAmountTolerance(openSum, remaining)
+  const amountLabel = cashDiscountMatch
+      ? `Passt mit ${String(cashDiscountMatch.percent).replace(".", ",")} % Skonto`
+      : getAmountMatchLabel(openSum, remaining)
+  const withinTolerance = cashDiscountMatch || isWithinAmountTolerance(openSum, remaining)
 
   if (!withinTolerance) {
-    return { score: 0, amountLabel: null, purposeMatches: [] }
+    return { score: 0, amountLabel: null, purposeMatches: [], cashDiscountMatch: null }
   }
 
-  if (openSum === remaining) score += 100
+  if (openSum === remaining || cashDiscountMatch) score += 100
   else score += Math.max(0, 60 - Math.abs(openSum - remaining))
 
   if (suggestion && document.customer?.id === suggestion.id) score += 80
   if (purposeMatches.length > 0) score += 50 + (purposeMatches.length * 10)
 
-  return { score, amountLabel, purposeMatches }
+  return { score, amountLabel, purposeMatches, cashDiscountMatch }
 }
 
 const getIncomingInvoiceSuggestionMeta = (statement, invoice, suggestion) => {
@@ -412,20 +440,23 @@ const getIncomingInvoiceSuggestionMeta = (statement, invoice, suggestion) => {
   const remaining = Math.abs(Number(calculateOpenSum(statement)))
   const openSum = Math.abs(Number(getInvoiceSum(invoice, true)))
   const purposeMatches = getMatchingPurposeParts(statement.text, [invoice.reference, invoice.description])
-  const amountLabel = getAmountMatchLabel(openSum, remaining)
+  const cashDiscountMatch = getCashDiscountMatch(statement, "incominginvoice", invoice)
-  const withinTolerance = isWithinAmountTolerance(openSum, remaining)
+  const amountLabel = cashDiscountMatch
+      ? `Passt mit ${String(cashDiscountMatch.percent).replace(".", ",")} % Skonto`
+      : getAmountMatchLabel(openSum, remaining)
+  const withinTolerance = cashDiscountMatch || isWithinAmountTolerance(openSum, remaining)
 
   if (!withinTolerance) {
-    return { score: 0, amountLabel: null, purposeMatches: [] }
+    return { score: 0, amountLabel: null, purposeMatches: [], cashDiscountMatch: null }
   }
 
-  if (openSum === remaining) score += 100
+  if (openSum === remaining || cashDiscountMatch) score += 100
   else score += Math.max(0, 60 - Math.abs(openSum - remaining))
 
   if (suggestion && invoice.vendor?.id === suggestion.id) score += 80
   if (purposeMatches.length > 0) score += 50 + (purposeMatches.length * 10)
 
-  return { score, amountLabel, purposeMatches }
+  return { score, amountLabel, purposeMatches, cashDiscountMatch }
 }
 
 const getRowSuggestions = (statement) => {
@@ -434,7 +465,7 @@ const getRowSuggestions = (statement) => {
   const topDocument = (entitySuggestion?.type === "customer" ? openDocuments.value.filter(doc => doc.customer?.id === entitySuggestion.id) : openDocuments.value)
       .map(document => {
         const meta = getDocumentSuggestionMeta(statement, document, entitySuggestion?.type === "customer" ? entitySuggestion : null)
-        return { ...document, suggestionScore: meta.score, suggestionAmountLabel: meta.amountLabel, suggestionPurposeMatches: meta.purposeMatches, suggestionKey: `document:${document.id}` }
+        return { ...document, suggestionScore: meta.score, suggestionAmountLabel: meta.amountLabel, suggestionPurposeMatches: meta.purposeMatches, suggestionCashDiscount: meta.cashDiscountMatch, suggestionKey: `document:${document.id}` }
       })
       .filter(document => !isSuggestionDismissed(statement.id, document.suggestionKey))
       .filter(document => document.suggestionScore >= 80 || document.suggestionPurposeMatches?.length > 0)
@@ -443,7 +474,7 @@ const getRowSuggestions = (statement) => {
   const topIncomingInvoice = (entitySuggestion?.type === "vendor" ? openIncomingInvoices.value.filter(invoice => invoice.vendor?.id === entitySuggestion.id) : openIncomingInvoices.value)
       .map(invoice => {
         const meta = getIncomingInvoiceSuggestionMeta(statement, invoice, entitySuggestion?.type === "vendor" ? entitySuggestion : null)
-        return { ...invoice, suggestionScore: meta.score, suggestionAmountLabel: meta.amountLabel, suggestionPurposeMatches: meta.purposeMatches, suggestionKey: `invoice:${invoice.id}` }
+        return { ...invoice, suggestionScore: meta.score, suggestionAmountLabel: meta.amountLabel, suggestionPurposeMatches: meta.purposeMatches, suggestionCashDiscount: meta.cashDiscountMatch, suggestionKey: `invoice:${invoice.id}` }
       })
       .filter(invoice => !isSuggestionDismissed(statement.id, invoice.suggestionKey))
       .filter(invoice => invoice.suggestionScore >= 80 || invoice.suggestionPurposeMatches?.length > 0)
@@ -551,6 +582,24 @@ const handleAssignIncomingInvoice = async (row, invoice, event) => {
   })
 }
 
+// Bucht die Zahlung zusammen mit dem vereinbarten Skonto, wenn Betrag und Frist zu den Skontobedingungen passen.
+const handleAssignWithCashDiscount = async (row, kind, entity, event) => {
+  event.stopPropagation()
+  const match = entity.suggestionCashDiscount
+  if (!match) return
+  try {
+    await saveAllocation({
+      [kind]: entity.id,
+      bankstatement: row.id,
+      amount: Number(calculateOpenSum(row)),
+      cashDiscountAmount: match.discount,
+      description: "Automatischer Vorschlag mit Skonto"
+    })
+  } catch (err) {
+    toast.add({ title: "Skonto konnte nicht gebucht werden", description: err?.data?.error, color: "error" })
+  }
+}
+
 const dismissSuggestion = (row, suggestionKey, event) => {
   event.stopPropagation()
   const bankingSettings = tempStore.settings?.banking || {}
@@ -927,7 +976,15 @@ onMounted(() => {
                   </UBadge>
                 </div>
               </div>
-              <UButton size="sm" color="emerald" @click="handleAssignDocument(selectedSuggestionRow.row, selectedSuggestionRow.suggestions.topDocument, $event)">
+              <UButton
+                  v-if="selectedSuggestionRow.suggestions.topDocument.suggestionCashDiscount"
+                  size="sm"
+                  color="warning"
+                  @click="handleAssignWithCashDiscount(selectedSuggestionRow.row, 'createddocument', selectedSuggestionRow.suggestions.topDocument, $event)"
+              >
+                Mit Skonto zuweisen
+              </UButton>
+              <UButton v-else size="sm" color="emerald" @click="handleAssignDocument(selectedSuggestionRow.row, selectedSuggestionRow.suggestions.topDocument, $event)">
                 Zuweisen
               </UButton>
               <UButton size="sm" color="gray" variant="ghost" @click="dismissSuggestion(selectedSuggestionRow.row, selectedSuggestionRow.suggestions.topDocument.suggestionKey, $event)">
@@ -950,7 +1007,15 @@ onMounted(() => {
                   </UBadge>
                 </div>
               </div>
-              <UButton size="sm" color="error" @click="handleAssignIncomingInvoice(selectedSuggestionRow.row, selectedSuggestionRow.suggestions.topIncomingInvoice, $event)">
+              <UButton
+                  v-if="selectedSuggestionRow.suggestions.topIncomingInvoice.suggestionCashDiscount"
+                  size="sm"
+                  color="warning"
+                  @click="handleAssignWithCashDiscount(selectedSuggestionRow.row, 'incominginvoice', selectedSuggestionRow.suggestions.topIncomingInvoice, $event)"
+              >
+                Mit Skonto zuweisen
+              </UButton>
+              <UButton v-else size="sm" color="error" @click="handleAssignIncomingInvoice(selectedSuggestionRow.row, selectedSuggestionRow.suggestions.topIncomingInvoice, $event)">
                 Zuweisen
               </UButton>
               <UButton size="sm" color="gray" variant="ghost" @click="dismissSuggestion(selectedSuggestionRow.row, selectedSuggestionRow.suggestions.topIncomingInvoice.suggestionKey, $event)">

frontend/pages/banking/statements/[mode]/[[id]].vue

@@ -1,6 +1,7 @@
 <script setup>
 import dayjs from "dayjs";
 import { BANK_ALLOCATION_TAX_ITEMS, getBankAllocationAmounts } from "~/utils/bankAllocationTax"
+import { matchCashDiscountPayment, sumSettledAllocations } from "~/utils/cashDiscount"
 import {
   DEPRECIATION_METHOD_ITEMS,
   EXPENSE_BOOKING_MODE_ITEMS,
@@ -54,7 +55,7 @@ const rebuildDocumentLists = () => {
     return {
       ...i,
       docTotal: useSum().getCreatedDocumentSum(i, createddocuments.value),
-      statementTotal: Number(i.statementallocations.reduce((n, {amount}) => n + amount, 0)),
+      statementTotal: Number(sumSettledAllocations(i.statementallocations)),
       openSum: useSum().getCreatedDocumentOpenAmount(i, createddocuments.value).toFixed(2)
     }
   })
@@ -62,7 +63,7 @@ const rebuildDocumentLists = () => {
   allocatedDocuments.value = documents.filter(i => i.statementallocations.find(x => x.bankstatement === itemInfo.value.id))
   allocatedIncomingInvoices.value = incominginvoices.value.filter(i => i.statementallocations.find(x => x.bankstatement === itemInfo.value.id))
   openIncomingInvoices.value = incominginvoices.value.filter(i =>
-      !i.archived && i.statementallocations.reduce((n, {amount}) => n + amount, 0).toFixed(2) !== getInvoiceSum(i, false)
+      !i.archived && sumSettledAllocations(i.statementallocations).toFixed(2) !== getInvoiceSum(i, false)
   )
 }
 
@@ -136,7 +137,7 @@ const separateIBAN = (input) => {
 const getInvoiceSum = (invoice, onlyOpenSum) => {
   let sum = Number(useSum().getIncomingInvoiceSum(invoice))
 
-  if (onlyOpenSum) sum = sum + Number(invoice.statementallocations.reduce((n, {amount}) => n + amount, 0))
+  if (onlyOpenSum) sum = sum + Number(sumSettledAllocations(invoice.statementallocations))
 
   if (invoice.expense) {
     return (sum * -1).toFixed(2)
@@ -420,6 +421,30 @@ const isWithinAmountTolerance = (candidateSum, remaining) => {
   return difference / reference <= 0.1
 }
 
+// Erkennt Zahlungen, die genau dem offenen Betrag abzüglich vereinbartem Skonto entsprechen und in der Frist liegen.
+const getCashDiscountMatch = (kind, entity) => {
+  const paymentDate = itemInfo.value?.date || itemInfo.value?.valueDate
+  if (kind === "createddocument") {
+    const days = entity.cashDiscountDays
+    return matchCashDiscountPayment({
+      open: entity.openSum,
+      payment: calculateOpenSum.value,
+      percent: entity.cashDiscountPercent,
+      dueDate: entity.documentDate && days !== null && days !== undefined && days !== ""
+          ? dayjs(entity.documentDate).add(Number(days), "day").format("YYYY-MM-DD")
+          : null,
+      paymentDate: paymentDate ? dayjs(paymentDate).format("YYYY-MM-DD") : null
+    })
+  }
+  return matchCashDiscountPayment({
+    open: getInvoiceSum(entity, true),
+    payment: calculateOpenSum.value,
+    percent: entity.cashDiscountPercent,
+    dueDate: entity.cashDiscountDueDate || null,
+    paymentDate: paymentDate ? dayjs(paymentDate).format("YYYY-MM-DD") : null
+  })
+}
+
 const getDocumentSuggestionMeta = (document, suggestion) => {
   let score = 0
   const remaining = Math.abs(Number(calculateOpenSum.value))
@@ -429,18 +454,22 @@ const getDocumentSuggestionMeta = (document, suggestion) => {
     document.title,
     document.description
   ])
-  const amountLabel = getAmountMatchLabel(openSum, remaining)
+  const cashDiscountMatch = getCashDiscountMatch("createddocument", document)
-  const withinTolerance = isWithinAmountTolerance(openSum, remaining)
+  const amountLabel = cashDiscountMatch
+      ? `Passt mit ${String(cashDiscountMatch.percent).replace(".", ",")} % Skonto`
+      : getAmountMatchLabel(openSum, remaining)
+  const withinTolerance = cashDiscountMatch || isWithinAmountTolerance(openSum, remaining)
 
   if (!withinTolerance) {
     return {
       score: 0,
       purposeMatches: [],
-      amountLabel: null
+      amountLabel: null,
+      cashDiscountMatch: null
     }
   }
 
-  if (openSum === remaining) score += 100
+  if (openSum === remaining || cashDiscountMatch) score += 100
   else score += Math.max(0, 60 - Math.abs(openSum - remaining))
 
   if (suggestion && document.customer?.id === suggestion.id) score += 80
@@ -449,7 +478,8 @@ const getDocumentSuggestionMeta = (document, suggestion) => {
   return {
     score,
     purposeMatches,
-    amountLabel
+    amountLabel,
+    cashDiscountMatch
   }
 }
 
@@ -461,18 +491,22 @@ const getInvoiceSuggestionMeta = (invoice, suggestion) => {
     invoice.reference,
     invoice.description
   ])
-  const amountLabel = getAmountMatchLabel(openSum, remaining)
+  const cashDiscountMatch = getCashDiscountMatch("incominginvoice", invoice)
-  const withinTolerance = isWithinAmountTolerance(openSum, remaining)
+  const amountLabel = cashDiscountMatch
+      ? `Passt mit ${String(cashDiscountMatch.percent).replace(".", ",")} % Skonto`
+      : getAmountMatchLabel(openSum, remaining)
+  const withinTolerance = cashDiscountMatch || isWithinAmountTolerance(openSum, remaining)
 
   if (!withinTolerance) {
     return {
       score: 0,
       purposeMatches: [],
-      amountLabel: null
+      amountLabel: null,
+      cashDiscountMatch: null
     }
   }
 
-  if (openSum === remaining) score += 100
+  if (openSum === remaining || cashDiscountMatch) score += 100
   else score += Math.max(0, 60 - Math.abs(openSum - remaining))
 
   if (suggestion && invoice.vendor?.id === suggestion.id) score += 80
@@ -481,7 +515,8 @@ const getInvoiceSuggestionMeta = (invoice, suggestion) => {
   return {
     score,
     purposeMatches,
-    amountLabel
+    amountLabel,
+    cashDiscountMatch
   }
 }
 
@@ -497,6 +532,7 @@ const suggestedDocuments = computed(() => {
           suggestionScore: meta.score,
           suggestionPurposeMatches: meta.purposeMatches,
           suggestionAmountLabel: meta.amountLabel,
+          suggestionCashDiscount: meta.cashDiscountMatch,
           suggestionKey: `document:${document.id}`
         }
       })
@@ -517,6 +553,7 @@ const suggestedIncomingInvoices = computed(() => {
           suggestionScore: meta.score,
           suggestionPurposeMatches: meta.purposeMatches,
           suggestionAmountLabel: meta.amountLabel,
+          suggestionCashDiscount: meta.cashDiscountMatch,
           suggestionKey: `invoice:${invoice.id}`
         }
       })
@@ -536,6 +573,7 @@ const fallbackSuggestedDocuments = computed(() => {
           suggestionScore: meta.score,
           suggestionPurposeMatches: meta.purposeMatches,
           suggestionAmountLabel: meta.amountLabel,
+          suggestionCashDiscount: meta.cashDiscountMatch,
           suggestionKey: `document:${document.id}`
         }
       })
@@ -556,6 +594,7 @@ const fallbackSuggestedIncomingInvoices = computed(() => {
           suggestionScore: meta.score,
           suggestionPurposeMatches: meta.purposeMatches,
           suggestionAmountLabel: meta.amountLabel,
+          suggestionCashDiscount: meta.cashDiscountMatch,
           suggestionKey: `invoice:${invoice.id}`
         }
       })
@@ -603,6 +642,76 @@ const getAllocationBookingModeLabel = (item) => {
   return "Sofortaufwand"
 }
 
+// Skonto: Die Zahlung gleicht zusammen mit dem Skonto den offenen Betrag des Belegs aus.
+const cashDiscountModalOpen = ref(false)
+const cashDiscountTarget = ref(null)
+const cashDiscountInput = ref(0)
+const savingCashDiscount = ref(false)
+const cashDiscountError = ref("")
+
+const getCashDiscountCandidate = (kind, entity) => {
+  const open = Number(kind === "createddocument" ? entity.openSum : getInvoiceSum(entity, true))
+  const payment = Number(manualAllocationSum.value)
+  if (!open || !payment || Math.sign(open) !== Math.sign(payment)) return null
+  if (Math.abs(payment) >= Math.abs(open) - 0.004) return null
+  return { open, payment, discount: Number((open - payment).toFixed(2)) }
+}
+
+const canBookCashDiscount = (kind, entity) => Boolean(getCashDiscountCandidate(kind, entity))
+
+const openCashDiscountModal = (kind, entity) => {
+  const candidate = getCashDiscountCandidate(kind, entity)
+  if (!candidate) return
+  cashDiscountTarget.value = {
+    kind,
+    id: entity.id,
+    label: kind === "createddocument"
+        ? `${entity.documentNumber} (${entity.customer?.name || "Ohne Kunde"})`
+        : `${entity.reference || "Eingangsbeleg"} (${entity.vendor?.name || "Ohne Lieferant"})`,
+    ...candidate
+  }
+  cashDiscountInput.value = Math.abs(candidate.discount)
+  cashDiscountError.value = ""
+  cashDiscountModalOpen.value = true
+}
+
+const cashDiscountPercent = computed(() => {
+  const target = cashDiscountTarget.value
+  if (!target || !target.open) return 0
+  return Math.abs(Number(cashDiscountInput.value || 0)) / Math.abs(target.open) * 100
+})
+
+const cashDiscountRemaining = computed(() => {
+  const target = cashDiscountTarget.value
+  if (!target) return 0
+  return Number((Math.abs(target.open) - Math.abs(target.payment) - Math.abs(Number(cashDiscountInput.value || 0))).toFixed(2))
+})
+
+const confirmCashDiscount = async () => {
+  const target = cashDiscountTarget.value
+  if (!target || savingCashDiscount.value) return
+  savingCashDiscount.value = true
+  try {
+    await saveAllocation({
+      [target.kind]: target.id,
+      bankstatement: itemInfo.value.id,
+      amount: target.payment,
+      cashDiscountAmount: Math.abs(Number(cashDiscountInput.value || 0)),
+      description: allocationDescription.value || "Zahlung mit Skonto"
+    })
+    cashDiscountModalOpen.value = false
+    cashDiscountTarget.value = null
+  } catch (err) {
+    cashDiscountError.value = err?.data?.error || "Zahlung und Skonto konnten nicht gebucht werden."
+  } finally {
+    savingCashDiscount.value = false
+  }
+}
+
+const getCashDiscountSplitLabel = (item) => (item.cashDiscountSplit || [])
+    .map(split => `${split.account} (${split.rate} %): ${displayCurrency(split.gross)}`)
+    .join(" · ")
+
 setup()
 </script>
 
@@ -726,6 +835,9 @@ setup()
                       {{ getAllocationTaxLabel(item) }} · Netto {{ displayCurrency(getBankAllocationAmounts(item).amountNet) }}
                       · Steuer {{ displayCurrency(getBankAllocationAmounts(item).amountTax) }}
                     </div>
+                    <div v-if="Number(item.cashDiscountAmount)" class="text-xs text-amber-700 dark:text-amber-400 mt-1">
+                      Skonto {{ displayCurrency(item.cashDiscountAmount) }}<span v-if="item.cashDiscountSplit?.length"> · {{ getCashDiscountSplitLabel(item) }}</span>
+                    </div>
                     <div class="mt-1 flex flex-wrap gap-1" v-if="item.bookingMode && item.bookingMode !== 'expense'">
                       <UBadge size="xs" color="warning" variant="soft">{{ getAllocationBookingModeLabel(item) }}</UBadge>
                       <UBadge size="xs" color="neutral" variant="soft" v-if="item.depreciationGroup">{{ item.depreciationGroup }}</UBadge>
@@ -756,6 +868,9 @@ setup()
                 </div>
                 <div class="text-right">
                   <div class="font-mono text-sm font-semibold">{{ displayCurrency(item.amount) }}</div>
+                  <div v-if="Number(item.cashDiscountAmount)" class="font-mono text-xs text-amber-600">
+                    + {{ displayCurrency(item.cashDiscountAmount) }} Skonto
+                  </div>
                   <UButton
                       icon="i-heroicons-trash"
                       color="error"
@@ -1003,6 +1118,15 @@ setup()
                   >
                     Rechnung zuweisen
                   </UButton>
+                  <UButton
+                      v-if="canBookCashDiscount('createddocument', document)"
+                      size="xs"
+                      color="warning"
+                      :variant="document.suggestionCashDiscount ? 'solid' : 'soft'"
+                      @click="openCashDiscountModal('createddocument', document)"
+                  >
+                    Mit Skonto
+                  </UButton>
                   <UButton
                       size="xs"
                       color="gray"
@@ -1037,6 +1161,15 @@ setup()
                   >
                     Beleg zuweisen
                   </UButton>
+                  <UButton
+                      v-if="canBookCashDiscount('incominginvoice', invoice)"
+                      size="xs"
+                      color="warning"
+                      :variant="invoice.suggestionCashDiscount ? 'solid' : 'soft'"
+                      @click="openCashDiscountModal('incominginvoice', invoice)"
+                  >
+                    Mit Skonto
+                  </UButton>
                   <UButton
                       size="xs"
                       color="gray"
@@ -1087,6 +1220,7 @@ setup()
                     <div class="text-right">
                       <div class="font-mono font-bold text-sm">{{ displayCurrency(document.openSum) }}</div>
                       <div class="text-xs text-gray-400">Offen</div>
+                      <UBadge v-if="getCashDiscountMatch('createddocument', document)" size="xs" color="warning" variant="subtle">Skonto passt</UBadge>
                     </div>
                     <UTooltip text="Zuweisen">
                       <UButton
@@ -1098,6 +1232,16 @@ setup()
                           @click="saveAllocation({createddocument: document.id, bankstatement: itemInfo.id, amount: Number(Number(document.openSum) < manualAllocationSum ? document.openSum : manualAllocationSum), description: allocationDescription})"
                       />
                     </UTooltip>
+                    <UTooltip text="Mit Skonto ausgleichen">
+                      <UButton
+                          v-if="!itemInfo.statementallocations.find(i => i.createddocument === document.id) && canBookCashDiscount('createddocument', document)"
+                          icon="i-heroicons-receipt-percent"
+                          size="sm"
+                          color="warning"
+                          variant="soft"
+                          @click="openCashDiscountModal('createddocument', document)"
+                      />
+                    </UTooltip>
                     <UButton
                         icon="i-heroicons-eye"
                         color="gray"
@@ -1146,6 +1290,7 @@ setup()
                         {{ displayCurrency(getInvoiceSum(item, true)) }}
                       </div>
                       <div class="text-xs text-gray-400">Offen</div>
+                      <UBadge v-if="getCashDiscountMatch('incominginvoice', item)" size="xs" color="warning" variant="subtle">Skonto passt</UBadge>
                     </div>
                     <UTooltip text="Zuweisen">
                       <UButton
@@ -1157,6 +1302,16 @@ setup()
                           @click="saveAllocation({incominginvoice: item.id, bankstatement: itemInfo.id, amount: Number(Math.abs(getInvoiceSum(item,true)) > Math.abs(manualAllocationSum) ? manualAllocationSum : getInvoiceSum(item,true)), description: allocationDescription})"
                       />
                     </UTooltip>
+                    <UTooltip text="Mit Skonto ausgleichen">
+                      <UButton
+                          v-if="!itemInfo.statementallocations.find(i => i.incominginvoice === item.id) && canBookCashDiscount('incominginvoice', item)"
+                          icon="i-heroicons-receipt-percent"
+                          size="sm"
+                          color="warning"
+                          variant="soft"
+                          @click="openCashDiscountModal('incominginvoice', item)"
+                      />
+                    </UTooltip>
                     <UButton
                         icon="i-heroicons-eye"
                         color="gray"
@@ -1180,6 +1335,70 @@ setup()
       </div>
     </div>
   </UDashboardPanelContent>
+
+  <UModal v-model:open="cashDiscountModalOpen" :ui="{ width: 'sm:max-w-lg' }">
+    <template #content>
+      <UCard v-if="cashDiscountTarget">
+        <template #header>
+          <div class="text-lg font-semibold">Mit Skonto ausgleichen</div>
+          <div class="text-sm text-gray-500 mt-0.5">{{ cashDiscountTarget.label }}</div>
+        </template>
+
+        <div class="space-y-4">
+          <div class="grid grid-cols-2 gap-2 text-sm">
+            <div class="text-gray-500">Offener Betrag</div>
+            <div class="text-right font-mono">{{ displayCurrency(Math.abs(cashDiscountTarget.open)) }}</div>
+            <div class="text-gray-500">Zahlung aus diesem Umsatz</div>
+            <div class="text-right font-mono">{{ displayCurrency(Math.abs(cashDiscountTarget.payment)) }}</div>
+          </div>
+
+          <UFormField label="Skonto (brutto)" :help="`${cashDiscountPercent.toFixed(2).replace('.', ',')} % des offenen Betrags`">
+            <UInput v-model="cashDiscountInput" type="number" step="0.01" min="0">
+              <template #trailing><span class="text-gray-500 text-xs">EUR</span></template>
+            </UInput>
+          </UFormField>
+
+          <UAlert
+              v-if="cashDiscountPercent > 5"
+              color="warning"
+              variant="subtle"
+              icon="i-heroicons-exclamation-triangle"
+              title="Ungewöhnlich hoher Skonto"
+              description="Bitte prüfen, ob es sich wirklich um Skonto handelt und nicht um eine Teilzahlung."
+          />
+          <UAlert
+              v-if="cashDiscountError"
+              color="error"
+              variant="subtle"
+              icon="i-heroicons-x-circle"
+              :description="cashDiscountError"
+          />
+          <div v-if="Math.abs(cashDiscountRemaining) >= 0.01" class="text-sm text-amber-600">
+            Danach bleiben {{ displayCurrency(cashDiscountRemaining) }} offen.
+          </div>
+          <p class="text-xs text-gray-500">
+            Der Skonto wird anteilig nach Steuersätzen auf die Skontokonten verteilt
+            ({{ cashDiscountTarget.kind === 'createddocument' ? 'gewährte' : 'erhaltene' }} Skonti) und korrigiert die
+            {{ cashDiscountTarget.kind === 'createddocument' ? 'Umsatzsteuer' : 'Vorsteuer' }} im Monat der Zahlung.
+          </p>
+        </div>
+
+        <template #footer>
+          <div class="flex justify-end gap-2">
+            <UButton color="neutral" variant="ghost" @click="cashDiscountModalOpen = false">Abbrechen</UButton>
+            <UButton
+                color="primary"
+                :loading="savingCashDiscount"
+                :disabled="!(Number(cashDiscountInput) > 0) || cashDiscountRemaining < -0.009"
+                @click="confirmCashDiscount"
+            >
+              Zahlung und Skonto buchen
+            </UButton>
+          </div>
+        </template>
+      </UCard>
+    </template>
+  </UModal>
 </template>
 
 <style scoped>

frontend/pages/createDocument/edit/[[id]].vue

@@ -6,6 +6,7 @@ import {useFunctions} from "~/composables/useFunctions.js";
 import EntityModalButtons from "~/components/EntityModalButtons.vue";
 import { documentTemplateHandlebars } from "~/utils/handlebars";
 import { getTitleSectionMove, moveTitleSection } from "~/utils/documentTitleSections.js";
+import { appendCashDiscountText, buildCashDiscountTerms, formatCashDiscountText, getCashDiscountTemplateContext } from "~/utils/cashDiscount";
 
 const dataStore = useDataStore()
 const profileStore = useProfileStore()
@@ -57,6 +58,8 @@ const itemInfo = ref({
   deliveryDateType: "Lieferdatum",
   dateOfPerformance: null,
   paymentDays: auth.activeTenantData.standardPaymentDays,
+  cashDiscountPercent: null,
+  cashDiscountDays: null,
   payment_type: "transfer",
   outgoingsepamandate: null,
   availableInPortal: false,
@@ -635,7 +638,11 @@ const setupPage = async () => {
         if (optionsToImport.deliveryDate) itemInfo.value.deliveryDate = linkedDocument.deliveryDate
         if (optionsToImport.deliveryDateEnd) itemInfo.value.deliveryDateEnd = linkedDocument.deliveryDateEnd
         if (optionsToImport.documentDate) itemInfo.value.documentDate = linkedDocument.documentDate
-        if (optionsToImport.paymentDays) itemInfo.value.paymentDays = linkedDocument.paymentDays
+        if (optionsToImport.paymentDays) {
+          itemInfo.value.paymentDays = linkedDocument.paymentDays
+          itemInfo.value.cashDiscountPercent = linkedDocument.cashDiscountPercent ?? null
+          itemInfo.value.cashDiscountDays = linkedDocument.cashDiscountDays ?? null
+        }
         if (optionsToImport.payment_type) itemInfo.value.payment_type = linkedDocument.payment_type
         if (optionsToImport.customSurchargePercentage) itemInfo.value.customSurchargePercentage = linkedDocument.customSurchargePercentage
         if (optionsToImport.contactPerson) itemInfo.value.contactPerson = linkedDocument.contactPerson
@@ -663,6 +670,8 @@ const setupPage = async () => {
         itemInfo.value.deliveryDateEnd = linkedDocument.deliveryDateEnd
         itemInfo.value.documentDate = linkedDocument.documentDate
         itemInfo.value.paymentDays = linkedDocument.paymentDays
+        itemInfo.value.cashDiscountPercent = linkedDocument.cashDiscountPercent ?? null
+        itemInfo.value.cashDiscountDays = linkedDocument.cashDiscountDays ?? null
         itemInfo.value.payment_type = linkedDocument.payment_type
         itemInfo.value.customSurchargePercentage = linkedDocument.customSurchargePercentage
         itemInfo.value.contactPerson = linkedDocument.contactPerson
@@ -833,6 +842,10 @@ const setCustomerData = async (customerId, loadOnlyAdress = false) => {
     itemInfo.value.address.country = customer.infoData.country
 
     if (!loadOnlyAdress && customer.customPaymentDays) itemInfo.value.paymentDays = customer.customPaymentDays
+    if (!loadOnlyAdress && customer.customCashDiscountPercent) {
+      itemInfo.value.cashDiscountPercent = customer.customCashDiscountPercent
+      itemInfo.value.cashDiscountDays = customer.customCashDiscountDays ?? null
+    }
     if (!loadOnlyAdress && customer.custom_payment_type) itemInfo.value.payment_type = customer.custom_payment_type
     if (!loadOnlyAdress) {
       itemInfo.value.taxType = normalizeTaxTypeValue(customer.customTaxType)
@@ -1118,8 +1131,54 @@ const checkAddressZip = async () => {
   }
 }
 
+// Pflichtangaben der E-Rechnung (ZUGFeRD) prüft das Backend, da Firmen- und Kundendaten dort vollständig vorliegen
+const eInvoiceDocumentTypes = ["invoices", "advanceInvoices", "cancellationInvoices", "serialInvoices"]
+const eInvoiceIssues = ref([])
+const eInvoiceCheckSource = computed(() => {
+  if (!loaded.value || isTemplateMode.value || !eInvoiceDocumentTypes.includes(itemInfo.value.type)) return null
+  const item = itemInfo.value
+  return JSON.stringify({
+    type: item.type,
+    customer: item.customer,
+    contact: item.contact,
+    project: item.project,
+    contract: item.contract,
+    address: item.address,
+    rows: item.rows,
+    taxType: item.taxType,
+    payment_type: item.payment_type,
+    outgoingsepamandate: item.outgoingsepamandate,
+    deliveryDateType: item.deliveryDateType,
+    usedAdvanceInvoices: item.usedAdvanceInvoices,
+    createddocument: item.createddocument,
+    created_by: item.created_by,
+  })
+})
+
+const refreshEInvoiceIssues = async () => {
+  const source = eInvoiceCheckSource.value
+  if (!source) {
+    eInvoiceIssues.value = []
+    return eInvoiceIssues.value
+  }
+  try {
+    const result = await useNuxtApp().$api("/api/functions/einvoice/check", {
+      method: "POST",
+      body: { document: JSON.parse(source) },
+    })
+    // Nur übernehmen, wenn sich der Beleg während der Anfrage nicht geändert hat
+    if (source === eInvoiceCheckSource.value) eInvoiceIssues.value = result?.issues || []
+  } catch (error) {
+    console.error(error)
+    eInvoiceIssues.value = [{ message: "E-Rechnung: Die Pflichtangaben konnten nicht geprüft werden", type: "breaking" }]
+  }
+  return eInvoiceIssues.value
+}
+
+watchDebounced(eInvoiceCheckSource, refreshEInvoiceIssues, { debounce: 500, immediate: true })
+
 const findDocumentErrors = computed(() => {
-  let errors = []
+  let errors = [...eInvoiceIssues.value]
 
   if (itemInfo.value.customer === null) errors.push({message: "Es ist kein Kunde ausgewählt", type: "breaking"})
   if (itemInfo.value.contact === null) errors.push({message: "Es ist kein Kontakt ausgewählt", type: "info"})
@@ -1357,6 +1416,17 @@ const documentTotal = computed(() => {
   }
 })
 
+// Skonto bezieht sich bei Schlussrechnungen auf die Restforderung nach Abzug der Abschläge.
+const cashDiscountTerms = computed(() => {
+  if (!["invoices", "advanceInvoices", "serialInvoices"].includes(itemInfo.value.type)) return null
+  return buildCashDiscountTerms({
+    percent: itemInfo.value.cashDiscountPercent,
+    days: itemInfo.value.cashDiscountDays,
+    documentDate: itemInfo.value.documentDate ? dayjs(itemInfo.value.documentDate).format("YYYY-MM-DD") : null,
+    amount: itemInfo.value.type === "invoices" ? documentTotal.value.totalSumToPay : documentTotal.value.totalGross
+  })
+})
+
 const documentReport = computed(() => {
 
   let totalProductsPurchasePrice = 0
@@ -1574,7 +1644,8 @@ const getDocumentData = async () => {
       kundenname: customerData && customerData.name,
       zahlungsziel_in_tagen: itemInfo.paymentDays,
       zahlungsart: itemInfo.payment_type === "transfer" ? "Überweisung" : "Lastschrift",
-      diesel_gesamtverbrauch: (itemInfo.agriculture && itemInfo.agriculture.dieselUsageTotal) && itemInfo.agriculture.dieselUsageTotal
+      diesel_gesamtverbrauch: (itemInfo.agriculture && itemInfo.agriculture.dieselUsageTotal) && itemInfo.agriculture.dieselUsageTotal,
+      ...getCashDiscountTemplateContext(cashDiscountTerms.value)
     }
   }
 
@@ -1684,7 +1755,7 @@ const getDocumentData = async () => {
     ],
     title: itemInfo.value.title,
     description: itemInfo.value.description,
-    endText: templateEndText(generateContext(itemInfo.value, contactData)),
+    endText: appendCashDiscountText(templateEndText(generateContext(itemInfo.value, contactData)), itemInfo.value.endText, cashDiscountTerms.value),
     startText: templateStartText(generateContext(itemInfo.value, contactData)),
     rows: rows,
     totalArray: [
@@ -1739,7 +1810,7 @@ const getDocumentData = async () => {
 
 const showDocument = ref(false)
 const uri = ref("")
-const generateDocument = async () => {
+const generateDocument = async (options = {}) => {
   showDocument.value = false
   const selectedLetterhead = getSelectedLetterhead()
 
@@ -1750,7 +1821,7 @@ const generateDocument = async () => {
 
   const path = selectedLetterhead.path
 
-  uri.value = await useFunctions().useCreatePDF(await getDocumentData(), path, "createdDocument")
+  uri.value = await useFunctions().useCreatePDF(await getDocumentData(), path, "createdDocument", options)
   /*uri.value = await useNuxtApp().$api("/api/functions/createinvoicepdf",{
     method: "POST",
     body: {
@@ -1819,6 +1890,8 @@ const saveSerialInvoice = async () => {
     project: normalizeEntityId(itemInfo.value.project),
     costcentre: itemInfo.value.costcentre,
     paymentDays: itemInfo.value.paymentDays,
+    cashDiscountPercent: itemInfo.value.cashDiscountPercent === "" || itemInfo.value.cashDiscountPercent === null ? null : Number(itemInfo.value.cashDiscountPercent),
+    cashDiscountDays: itemInfo.value.cashDiscountDays === "" || itemInfo.value.cashDiscountDays === null ? null : Number(itemInfo.value.cashDiscountDays),
     payment_type: itemInfo.value.payment_type,
     outgoingsepamandate: normalizeEntityId(itemInfo.value.outgoingsepamandate),
     deliveryDateType: "Leistungszeitraum",
@@ -1935,6 +2008,8 @@ const saveDocument = async (state, resetup = false) => {
     deliveryDate: itemInfo.value.deliveryDate,
     deliveryDateEnd: itemInfo.value.deliveryDateEnd,
     paymentDays: itemInfo.value.paymentDays,
+    cashDiscountPercent: itemInfo.value.cashDiscountPercent === "" || itemInfo.value.cashDiscountPercent === null ? null : Number(itemInfo.value.cashDiscountPercent),
+    cashDiscountDays: itemInfo.value.cashDiscountDays === "" || itemInfo.value.cashDiscountDays === null ? null : Number(itemInfo.value.cashDiscountDays),
     payment_type: itemInfo.value.payment_type,
     outgoingsepamandate: normalizeEntityId(itemInfo.value.outgoingsepamandate),
     deliveryDateType: itemInfo.value.deliveryDateType,
@@ -1996,6 +2071,18 @@ const saveFinalizedCostCentres = async () => {
 const selectedTab = ref("0")
 
 const closeDocument = async () => {
+  // Vor Vorschau und Fertigstellung mit dem aktuellen Stand prüfen, nicht mit dem letzten (entprellten) Ergebnis
+  await refreshEInvoiceIssues()
+  const breakingErrors = findDocumentErrors.value.filter(i => i.type === "breaking")
+  if (breakingErrors.length > 0) {
+    selectedTab.value = "0"
+    toast.add({
+      title: "Beleg kann nicht fertiggestellt werden",
+      description: breakingErrors.map(i => i.message).join(" · "),
+      color: "error",
+    })
+    return
+  }
 
   if(selectedTab.value === "0") {
     await generateDocument()
@@ -2005,7 +2092,16 @@ const closeDocument = async () => {
 
     await saveDocument("Gebucht")
 
+    try {
       await uploadGeneratedDocument()
+    } catch (error) {
+      console.error(error)
+      toast.add({
+        title: "PDF bzw. E-Rechnung konnte nicht erstellt werden",
+        description: error?.data?.error || error?.message,
+        color: "error",
+      })
+    }
 
     guard.value = false
 
@@ -2019,7 +2115,14 @@ const closeDocument = async () => {
 
 // Erzeugt die PDF aus dem aktuellen Stand und hängt sie an den Beleg an, ohne den Datensatz zu speichern
 const uploadGeneratedDocument = async () => {
-  await generateDocument()
+  // Rechnungen werden als E-Rechnung (ZUGFeRD) abgelegt; das XML erzeugt das Backend aus dem gespeicherten Beleg
+  await generateDocument({
+    createdDocumentId: itemInfo.value.id,
+    onResult: (result) => {
+      const hints = (result?.einvoiceIssues || []).map(i => i.message)
+      if (hints.length) toast.add({ title: "E-Rechnung mit Hinweisen erstellt", description: hints.join(" · "), color: "warning" })
+    },
+  })
 
   if (!uri.value) throw new Error("PDF konnte nicht erzeugt werden")
 
@@ -2690,6 +2793,39 @@ const setRowData = async (row, service = {sellingPriceComposed: {}}, product = {
                       class="w-full"
                   />
                 </UFormField>
+                <UFormField
+                    v-if="['invoices', 'advanceInvoices', 'serialInvoices'].includes(itemInfo.type)"
+                    class="min-w-0 flex-1"
+                    label="Skonto:"
+                    :help="cashDiscountTerms ? formatCashDiscountText(cashDiscountTerms) : undefined"
+                >
+                  <div class="flex gap-1">
+                    <UInput
+                        type="number"
+                        step="0.01"
+                        min="0"
+                        max="10"
+                        placeholder="%"
+                        v-model="itemInfo.cashDiscountPercent"
+                        class="w-full"
+                    >
+                      <template #trailing>
+                        <span class="text-gray-500 dark:text-gray-400 text-xs">%</span>
+                      </template>
+                    </UInput>
+                    <UInput
+                        type="number"
+                        min="0"
+                        placeholder="Tage"
+                        v-model="itemInfo.cashDiscountDays"
+                        class="w-full"
+                    >
+                      <template #trailing>
+                        <span class="text-gray-500 dark:text-gray-400 text-xs">Tage</span>
+                      </template>
+                    </UInput>
+                  </div>
+                </UFormField>
                 <UFormField
                     class="min-w-0 flex-1"
                     label="Individueller Aufschlag:"

frontend/pages/createDocument/index.vue

@@ -164,6 +164,7 @@
 </template>
 
 <script setup>
+import { sumSettledAllocations } from "~/utils/cashDiscount"
 import CreateDocumentModal from "~/components/createDocumentModal.vue"
 import CreateDocumentFromTemplateModal from "~/components/createDocumentFromTemplateModal.vue"
 import dayjs from "dayjs";
@@ -337,10 +338,7 @@ const documentAmounts = computed(() => {
 
   items.value.forEach((item) => {
     const amount = sum.getCreatedDocumentSum(item, items.value)
-    const amountPaid = (item.statementallocations || []).reduce(
+    const amountPaid = sumSettledAllocations(item.statementallocations || [])
-        (total, allocation) => total + Number(allocation.amount || 0),
-        0
-    )
 
     result.set(item.id, {
       amount,

frontend/pages/createDocument/show/[id].vue

@@ -427,6 +427,7 @@ const togglePortalRelease = async () => {
             <div>
               <p class="text-xs text-gray-500">Betrag</p>
               <p class="font-medium">{{ formatCurrency(allocation.amount) }}</p>
+                    <p v-if="Number(allocation.cashDiscountAmount)" class="text-xs text-amber-600">+ {{ formatCurrency(allocation.cashDiscountAmount) }} Skonto</p>
             </div>
             <div>
               <p class="text-xs text-gray-500">Text</p>

frontend/pages/incomingInvoices/[mode]/[id].vue

@@ -34,6 +34,8 @@ const itemInfo = ref({
   reference: "",
   date:  null,
   dueDate: null,
+  cashDiscountPercent: null,
+  cashDiscountDueDate: null,
   paymentType: "Überweisung",
   description: "",
   state: "Entwurf",
@@ -147,6 +149,28 @@ const setDateFieldToToday = (field) => {
   itemInfo.value[field] = dayjs().toDate()
 }
 
+// Skontofrist als reines Datum speichern, damit der Vergleich mit dem Zahlungsdatum nicht durch Zeitzonen kippt.
+const setCashDiscountDueDate = (value) => {
+  itemInfo.value.cashDiscountDueDate = value ? dayjs(value.toString()).format("YYYY-MM-DD") : null
+}
+
+// Lieferanten-Vorgabe nur bei bewusster Auswahl übernehmen, nicht beim Laden eines Belegs.
+const applyVendorCashDiscount = (vendorId) => {
+  const vendor = vendors.value.find((item) => item.id === vendorId)
+  if (!vendor?.cashDiscountPercent || itemInfo.value.cashDiscountPercent) return
+  itemInfo.value.cashDiscountPercent = vendor.cashDiscountPercent
+  if (itemInfo.value.date && vendor.cashDiscountDays !== null && vendor.cashDiscountDays !== undefined) {
+    itemInfo.value.cashDiscountDueDate = dayjs(itemInfo.value.date).add(vendor.cashDiscountDays, "day").format("YYYY-MM-DD")
+  }
+}
+
+const cashDiscountAmount = computed(() => {
+  const percent = Number(itemInfo.value.cashDiscountPercent || 0)
+  if (!(percent > 0)) return null
+  const gross = (itemInfo.value.accounts || []).reduce((sum, account) => sum + Number(account.amountNet || 0) + Number(account.amountTax || 0), 0)
+  return Number((Math.abs(gross) * percent / 100).toFixed(2))
+})
+
 const getDateButtonLabel = (value, emptyLabel = "Kein Datum") => value ? dayjs(value).format('DD.MM.YYYY') : emptyLabel
 const formatDate = (value) => value ? dayjs(value).format("DD.MM.YYYY") : "-"
 const formatMoney = (value) => `${Number(value || 0).toFixed(2).replace(".", ",")} €`
@@ -333,6 +357,9 @@ const updateIncomingInvoice = async (setBooked = false) => {
 
   let item = { ...itemInfo.value }
   item.accounts = (item.accounts || []).map((account) => ensureDepreciationDefaults({ ...account }, item.date))
+  const cashDiscountPercent = Number(item.cashDiscountPercent)
+  item.cashDiscountPercent = Number.isFinite(cashDiscountPercent) && cashDiscountPercent > 0 ? cashDiscountPercent : null
+  item.cashDiscountDueDate = item.cashDiscountPercent && item.cashDiscountDueDate ? dayjs(item.cashDiscountDueDate).format("YYYY-MM-DD") : null
   delete item.files
   item.state = keepBooked ? "Gebucht" : "Entwurf"
 
@@ -569,6 +596,14 @@ const hasBlockingIncomingInvoiceErrors = computed(() => blockingIncomingInvoiceE
                   <dt class="text-gray-500">Fälligkeitsdatum</dt>
                   <dd class="font-medium">{{ formatDate(itemInfo.dueDate) }}</dd>
                 </div>
+                <div v-if="itemInfo.cashDiscountPercent">
+                  <dt class="text-gray-500">Skonto</dt>
+                  <dd class="font-medium">
+                    {{ String(itemInfo.cashDiscountPercent).replace(".", ",") }} %
+                    <span v-if="cashDiscountAmount">({{ formatMoney(cashDiscountAmount) }})</span>
+                    <span v-if="itemInfo.cashDiscountDueDate"> bis {{ formatDate(itemInfo.cashDiscountDueDate) }}</span>
+                  </dd>
+                </div>
                 <div>
                   <dt class="text-gray-500">Bankbuchungsdatum</dt>
                   <dd class="font-medium">{{ bankBookingDateLabel }}</dd>
@@ -602,6 +637,7 @@ const hasBlockingIncomingInvoiceErrors = computed(() => blockingIncomingInvoiceE
                   <div>
                     <p class="text-xs text-gray-500">Betrag</p>
                     <p class="font-medium">{{ formatMoney(allocation.amount) }}</p>
+                    <p v-if="Number(allocation.cashDiscountAmount)" class="text-xs text-amber-600">+ {{ formatMoney(allocation.cashDiscountAmount) }} Skonto</p>
                   </div>
                   <div>
                     <p class="text-xs text-gray-500">Text</p>
@@ -636,6 +672,7 @@ const hasBlockingIncomingInvoiceErrors = computed(() => blockingIncomingInvoiceE
                       :disabled="mode === 'show'"
                       :filter-fields="['name', 'vendorNumber']"
                       :color="itemInfo.vendor ? 'primary' : 'error'"
+                      @update:model-value="applyVendorCashDiscount"
                   >
                     <template #default>
                       {{ vendors.find(v => v.id === itemInfo.vendor)?.name || 'Bitte wählen' }}
@@ -656,7 +693,7 @@ const hasBlockingIncomingInvoiceErrors = computed(() => blockingIncomingInvoiceE
                       v-if="mode !== 'show'"
                       type="vendors"
                       :id="itemInfo.vendor"
-                      @return-data="(data) => itemInfo.vendor = data.id"
+                      @return-data="(data) => { itemInfo.vendor = data.id; applyVendorCashDiscount(data.id) }"
                   />
                 </div>
               </UFormField>
@@ -735,6 +772,47 @@ const hasBlockingIncomingInvoiceErrors = computed(() => blockingIncomingInvoiceE
                 </UPopover>
               </UFormField>
 
+              <UFormField
+                  label="Skonto"
+                  :help="cashDiscountAmount ? `Abzug ${formatMoney(cashDiscountAmount)} bei Zahlung in der Frist` : undefined"
+              >
+                <UInput
+                    type="number"
+                    step="0.01"
+                    min="0"
+                    max="10"
+                    placeholder="z. B. 2"
+                    v-model="itemInfo.cashDiscountPercent"
+                    :disabled="mode === 'show'"
+                    class="w-full"
+                >
+                  <template #trailing><span class="text-gray-500 text-xs">%</span></template>
+                </UInput>
+              </UFormField>
+
+              <UFormField label="Skonto bis">
+                <UPopover class="w-full" :content="{ side: 'bottom', align: 'start' }">
+                  <UButton
+                      block
+                      icon="i-heroicons-calendar"
+                      :label="getDateButtonLabel(itemInfo.cashDiscountDueDate, 'Keine Skontofrist')"
+                      :disabled="mode === 'show' || !itemInfo.cashDiscountPercent"
+                      color="neutral"
+                      variant="outline"
+                      class="w-full justify-start"
+                  />
+                  <template #content>
+                    <div class="p-2">
+                      <UCalendar
+                          :model-value="getCalendarValue(itemInfo.cashDiscountDueDate)"
+                          @update:model-value="setCashDiscountDueDate"
+                          :week-starts-on="1"
+                      />
+                    </div>
+                  </template>
+                </UPopover>
+              </UFormField>
+
               <UFormField label="Beschreibung / Notiz" class="md:col-span-2">
                 <UTextarea class="w-full" v-model="itemInfo.description" :rows="2" autoresize :disabled="mode === 'show'" />
               </UFormField>

frontend/pages/incomingInvoices/index.vue

@@ -1,4 +1,5 @@
 <script setup>
+import { sumSettledAllocations } from "~/utils/cashDiscount"
 import dayjs from "dayjs"
 import {useSum} from "~/composables/useSum.js";
 
@@ -199,8 +200,8 @@ const getInvoiceSum = (invoice) => {
 }
 
 const getPaidAmount = (item) => {
-  let amountPaid = 0
+  // Gebuchter Skonto zählt zum ausgeglichenen Betrag.
-  item.statementallocations.forEach(allocation => amountPaid += allocation.amount)
+  const amountPaid = sumSettledAllocations(item.statementallocations || [])
   return Number(Math.abs(amountPaid).toFixed(2))
 }
 

frontend/pages/settings/tenant.vue

@@ -1,4 +1,5 @@
 <script setup>
+import { resolveCashDiscountAccounts } from "~/utils/cashDiscount"
 import {
   TAX_EVALUATION_PERIOD_OPTIONS,
   normalizeTaxEvaluationPeriod
@@ -273,6 +274,20 @@ watch(() => auth.activeTenantData?.portalConfig, (config) => {
 })
 const accountChart = ref(auth.activeTenantData.accountChart || "skr03")
 const taxEvaluationPeriod = ref(normalizeTaxEvaluationPeriod(auth.activeTenantData.taxEvaluationPeriod))
+const buildCashDiscountForm = (config) => {
+  const accounts = resolveCashDiscountAccounts(config)
+  return { received: { ...accounts.received }, granted: { ...accounts.granted } }
+}
+const cashDiscountAccounts = ref(buildCashDiscountForm(auth.activeTenantData?.cashDiscountAccounts))
+const cashDiscountRateLabels = { "19": "19 %", "7": "7 %", "0": "ohne USt" }
+const saveCashDiscountAccounts = async () => {
+  try {
+    await updateTenant({ cashDiscountAccounts: cashDiscountAccounts.value })
+    toast.add({ title: "Skontokonten gespeichert", color: "success" })
+  } catch (err) {
+    toast.add({ title: "Skontokonten konnten nicht gespeichert werden", description: err?.data?.error, color: "error" })
+  }
+}
 const accountChartOptions = [
   { label: "SKR 03", value: "skr03" },
   { label: "Verein", value: "verein" }
@@ -293,6 +308,7 @@ const updateTenant = async (newData) => {
     features.value = { ...defaultFeatures, ...(res?.features || {}) }
     businessInfo.value = normalizeBusinessInfo(res?.businessInfo)
     taxEvaluationPeriod.value = normalizeTaxEvaluationPeriod(res?.taxEvaluationPeriod)
+    cashDiscountAccounts.value = buildCashDiscountForm(res?.cashDiscountAccounts)
   }
 }
 const saveFeatures = async () => {
@@ -776,6 +792,32 @@ onMounted(() => {
             >
               Zeitraum speichern
             </UButton>
+            <div class="mt-6">
+              <div class="text-sm font-medium">Skontokonten</div>
+              <p class="text-xs text-muted mt-1">
+                DATEV-Automatikkonten für Skonto bei Zahlungen. Standard ist SKR 03.
+              </p>
+              <div class="mt-3 grid grid-cols-1 gap-4 md:grid-cols-2">
+                <div v-for="side in ['received', 'granted']" :key="side" class="space-y-2">
+                  <div class="text-xs font-semibold uppercase text-muted">
+                    {{ side === 'received' ? 'Erhaltene Skonti (Eingangsbelege)' : 'Gewährte Skonti (Ausgangsbelege)' }}
+                  </div>
+                  <UFormField
+                      v-for="rate in ['19', '7', '0']"
+                      :key="`${side}-${rate}`"
+                      :label="cashDiscountRateLabels[rate]"
+                  >
+                    <UInput v-model="cashDiscountAccounts[side][rate]" inputmode="numeric"/>
+                  </UFormField>
+                </div>
+              </div>
+            </div>
+            <UButton
+                class="mt-3"
+                @click="saveCashDiscountAccounts"
+            >
+              Skontokonten speichern
+            </UButton>
           </UForm>
         </UCard>
 

frontend/pages/settings/texttemplates.vue

@@ -29,12 +29,18 @@ const variableDefinitions = [
   { key: '{{titel}}', label: 'Titel', desc: 'Titel des Kunden' },
   { key: '{{zahlungsziel_in_tagen}}', label: 'Zahlungsziel', desc: 'In Tagen' },
   { key: '{{lohnkosten}}', label: 'Lohnkosten', desc: 'Ausgewiesene Lohnkosten' },
+  { key: '{{skonto_hinweis}}', label: 'Skonto-Hinweis', desc: 'Kompletter Satz; ohne Skontovariable wird er automatisch vor den Endtext gesetzt' },
+  { key: '{{skonto_prozent}}', label: 'Skonto %', desc: 'Skontosatz' },
+  { key: '{{skonto_datum}}', label: 'Skonto bis', desc: 'Datum der Skontofrist' },
+  { key: '{{skonto_betrag}}', label: 'Skontobetrag', desc: 'Abzugsbetrag in Euro' },
+  { key: '{{zahlbetrag_mit_skonto}}', label: 'Zahlbetrag mit Skonto', desc: 'Rechnungsbetrag abzüglich Skonto' },
 ]
 
 const conditionalExamples = [
   '{{#if vorname}}Hallo {{vorname}},{{/if}}',
   '{{#if (eq zahlungsart "Überweisung")}}Bitte überweisen Sie den Betrag.{{/if}}',
   '{{#if (gt zahlungsziel_in_tagen 14)}}Vielen Dank für Ihre Zahlung innerhalb des erweiterten Zahlungsziels.{{/if}}',
+  '{{#if skonto_prozent}}Bei Zahlung bis {{skonto_datum}} ziehen Sie bitte {{skonto_prozent}} % Skonto ab.{{/if}}',
 ]
 
 // --- Shortcuts ---

frontend/stores/data.js

@@ -345,6 +345,18 @@ export const useDataStore = defineStore('data', () => {
                     inputType: "number",
                     inputColumn: "Allgemeines",
                     sortable: true
+                },{
+                    key: "customCashDiscountPercent",
+                    label: "Skonto in %",
+                    inputType: "number",
+                    inputColumn: "Allgemeines",
+                    disabledInTable: true
+                },{
+                    key: "customCashDiscountDays",
+                    label: "Skontofrist in Tagen",
+                    inputType: "number",
+                    inputColumn: "Allgemeines",
+                    disabledInTable: true
                 },{
                     key: "custom_payment_type",
                     label: "Zahlungsart",
@@ -2007,6 +2019,18 @@ export const useDataStore = defineStore('data', () => {
                     inputType: "bool",
                     component: sepa
                 },
+                {
+                    key: "cashDiscountPercent",
+                    label: "Skonto in %",
+                    inputType: "number",
+                    disabledInTable: true
+                },
+                {
+                    key: "cashDiscountDays",
+                    label: "Skontofrist in Tagen",
+                    inputType: "number",
+                    disabledInTable: true
+                },
                 {
                     key: "defaultPaymentMethod",
                     label: "Standard Zahlungsmethode",

frontend/utils/bankAllocationTax.ts

@@ -1,3 +1,5 @@
+import { getCashDiscountTaxBreakdown } from "./cashDiscount"
+
 export const BANK_ALLOCATION_TAX_ITEMS = [
     { value: "9", label: "19 % Vorsteuer", rate: 19, kind: "input" },
     { value: "8", label: "7 % Vorsteuer", rate: 7, kind: "input" },
@@ -25,19 +27,19 @@ export function getBankAllocationAmounts(allocation: any) {
 }
 
 export function getBankAllocationTaxBreakdown(allocation: any) {
-    const output = { net19: 0, tax19: 0, net7: 0, tax7: 0, net0: 0 }
+    // Skonto auf zugeordnete Belege korrigiert die Steuer im Zeitraum der Zahlung.
-    const input = { ...output }
+    const { output, input } = getCashDiscountTaxBreakdown(allocation)
     if (!isDirectBankAllocation(allocation)) return { output, input }
     const { amountNet, amountTax, rate, kind } = getBankAllocationAmounts(allocation)
     if (kind === "none") return { output, input }
     const target = kind === "input" ? input : output
     const sign = kind === "input" ? -1 : 1
     if (rate === 19) {
-        target.net19 = amountNet * sign
+        target.net19 += amountNet * sign
-        target.tax19 = amountTax * sign
+        target.tax19 += amountTax * sign
     } else if (rate === 7) {
-        target.net7 = amountNet * sign
+        target.net7 += amountNet * sign
-        target.tax7 = amountTax * sign
+        target.tax7 += amountTax * sign
     }
     return { output, input }
 }

frontend/utils/cashDiscount.ts

@@ -0,0 +1,162 @@
+// Skonto wird an der Bankzuordnung gespeichert (cashDiscountAmount, gleiches Vorzeichen wie amount).
+// Zahlbetrag und Skonto gleichen den Beleg gemeinsam aus; der Bankumsatz selbst enthält nur amount.
+
+export const CASH_DISCOUNT_RATES = ["19", "7", "0"] as const
+
+export const DEFAULT_CASH_DISCOUNT_ACCOUNTS = {
+    received: { "19": "3736", "7": "3731", "0": "3730" },
+    granted: { "19": "8736", "7": "8731", "0": "8730" },
+}
+
+export const getAllocationCashDiscount = (allocation: any) => Number(allocation?.cashDiscountAmount || 0)
+
+export const getAllocationSettledAmount = (allocation: any) =>
+    Number(allocation?.amount || 0) + getAllocationCashDiscount(allocation)
+
+export const sumSettledAllocations = (allocations: any[] = []) =>
+    (allocations || []).reduce((sum, allocation) => sum + getAllocationSettledAmount(allocation), 0)
+
+export const hasCashDiscount = (allocation: any) =>
+    !allocation?.archived && Array.isArray(allocation?.cashDiscountSplit) && allocation.cashDiscountSplit.length > 0
+
+// Steuerkorrektur nach § 17 UStG im Zeitraum der Zahlung.
+// Ausgangsbelege mindern die Umsatzsteuer, Eingangsbelege die Vorsteuer (Vorzeichen aus der Zahlung).
+export function getCashDiscountTaxBreakdown(allocation: any) {
+    const output = { net19: 0, tax19: 0, net7: 0, tax7: 0, net0: 0 }
+    const input = { ...output }
+    if (!hasCashDiscount(allocation)) return { output, input }
+
+    const isOutgoing = Boolean(allocation.createddocument || allocation.cd_id)
+    const target = isOutgoing ? output : input
+    const sign = isOutgoing ? -1 : 1
+
+    for (const item of allocation.cashDiscountSplit) {
+        const net = Number(item?.net || 0) * sign
+        const tax = Number(item?.tax || 0) * sign
+        if (Number(item?.rate) === 19) {
+            target.net19 += net
+            target.tax19 += tax
+        } else if (Number(item?.rate) === 7) {
+            target.net7 += net
+            target.tax7 += tax
+        } else {
+            target.net0 += net
+        }
+    }
+    return { output, input }
+}
+
+export const resolveCashDiscountAccounts = (config: any) => {
+    const result = {
+        received: { ...DEFAULT_CASH_DISCOUNT_ACCOUNTS.received },
+        granted: { ...DEFAULT_CASH_DISCOUNT_ACCOUNTS.granted },
+    }
+    for (const side of ["received", "granted"] as const) {
+        for (const rate of CASH_DISCOUNT_RATES) {
+            const value = config?.[side]?.[rate]
+            if (value !== undefined && value !== null && String(value).trim()) result[side][rate] = String(value).trim()
+        }
+    }
+    return result
+}
+
+// ---------------------------------------------------------------------------
+// Skonto-Bedingungen auf Belegen (gleiche Logik wie backend/src/modules/cash-discount.ts)
+// ---------------------------------------------------------------------------
+
+const roundMoney = (value: number) => Number(value.toFixed(2))
+const formatEuro = (value: number) => new Intl.NumberFormat("de-DE", { style: "currency", currency: "EUR" }).format(value)
+const formatGermanDate = (value: string) => {
+    const [year, month, day] = value.split("-")
+    return `${day}.${month}.${year}`
+}
+
+const addDays = (date: any, days: number) => {
+    if (!date) return null
+    const iso = typeof date === "string" ? date.slice(0, 10) : new Date(date?.toISOString?.() || date).toISOString().slice(0, 10)
+    const parsed = new Date(`${iso}T00:00:00Z`)
+    if (Number.isNaN(parsed.getTime())) return null
+    parsed.setUTCDate(parsed.getUTCDate() + days)
+    return parsed.toISOString().slice(0, 10)
+}
+
+export function buildCashDiscountTerms({ percent, days, documentDate, dueDate, amount }: any) {
+    const normalizedPercent = Number(percent)
+    if (!Number.isFinite(normalizedPercent) || normalizedPercent <= 0 || !Number.isFinite(Number(amount)) || !Number(amount)) return null
+    const normalizedDays = days === null || days === undefined || days === "" ? null : Number(days)
+    const computedDueDate = dueDate
+        ? String(dueDate).slice(0, 10)
+        : normalizedDays !== null && Number.isFinite(normalizedDays) ? addDays(documentDate, normalizedDays) : null
+    const discount = roundMoney(Number(amount) * normalizedPercent / 100)
+    return {
+        percent: normalizedPercent,
+        days: normalizedDays !== null && Number.isFinite(normalizedDays) ? normalizedDays : null,
+        dueDate: computedDueDate,
+        discount,
+        payable: roundMoney(Number(amount) - discount),
+    }
+}
+
+export function formatCashDiscountText(terms: any) {
+    if (!terms) return ""
+    const percent = String(terms.percent).replace(".", ",")
+    const deadline = terms.dueDate
+        ? `bis zum ${formatGermanDate(terms.dueDate)}`
+        : terms.days !== null ? `innerhalb von ${terms.days} Tagen` : "bei sofortiger Zahlung"
+    return `Bei Zahlung ${deadline} gewähren wir ${percent} % Skonto (${formatEuro(Math.abs(terms.discount))}), Zahlbetrag ${formatEuro(Math.abs(terms.payable))}.`
+}
+
+export function getCashDiscountTemplateContext(terms: any) {
+    if (!terms) return {}
+    return {
+        skonto_prozent: String(terms.percent).replace(".", ","),
+        skonto_tage: terms.days,
+        skonto_datum: terms.dueDate ? formatGermanDate(terms.dueDate) : null,
+        skonto_betrag: formatEuro(Math.abs(terms.discount)),
+        zahlbetrag_mit_skonto: formatEuro(Math.abs(terms.payable)),
+        skonto_hinweis: formatCashDiscountText(terms),
+    }
+}
+
+export function appendCashDiscountText(renderedText: string, template: string | null | undefined, terms: any) {
+    if (!terms || /skonto_/i.test(String(template || ""))) return renderedText
+    const sentence = formatCashDiscountText(terms)
+    return renderedText ? `${sentence}\n\n${renderedText}` : sentence
+}
+
+// Liegt eine Zahlung innerhalb der Skontofrist und passt sie zum Betrag abzüglich Skonto?
+export function matchCashDiscountPayment({ open, payment, percent, dueDate, paymentDate }: any) {
+    const openAmount = Math.abs(Number(open || 0))
+    const paid = Math.abs(Number(payment || 0))
+    const rate = Number(percent || 0)
+    if (!openAmount || !paid || !(rate > 0)) return null
+    if (dueDate && paymentDate && String(paymentDate).slice(0, 10) > String(dueDate).slice(0, 10)) return null
+    const expected = roundMoney(openAmount * (1 - rate / 100))
+    if (Math.abs(expected - paid) > 0.05) return null
+    return { discount: roundMoney(openAmount - paid), percent: rate }
+}
+
+// Nettowirkung von Skonto für die BWA: gewährter Skonto mindert Erlöse, erhaltener Skonto den Aufwand.
+// Vorzeichen: Erlösminderung positiv; Aufwand im Vorzeichen der Eingangsbelege (Ausgaben positiv).
+export function getCashDiscountNetTotals(allocations: any[] = []) {
+    let grantedNet = 0
+    let receivedNet = 0
+    let receivedGross = 0
+    for (const allocation of allocations || []) {
+        if (!hasCashDiscount(allocation)) continue
+        const isOutgoing = Boolean(allocation.createddocument || allocation.cd_id)
+        for (const item of allocation.cashDiscountSplit) {
+            if (isOutgoing) grantedNet += Number(item?.net || 0)
+            else {
+                receivedNet += Number(item?.net || 0)
+                receivedGross += Number(item?.gross || 0)
+            }
+        }
+    }
+    return {
+        grantedNet: roundMoney(grantedNet),
+        // Eingangsbelege: Zahlungen (und damit Skonto) sind negativ, Aufwand wird positiv geführt.
+        receivedNet: roundMoney(-receivedNet),
+        receivedGross: roundMoney(-receivedGross),
+    }
+}