feat(lexware): add integration foundation

frontend/athena/app/api/lexware/settings/route.ts

@@ -0,0 +1,18 @@
+import { NextRequest } from "next/server";
+
+import { proxyHermesRequest } from "@/lib/server/hermes-proxy";
+import { assertSameOrigin } from "@/lib/server/request-guards";
+
+export async function GET(request: NextRequest) {
+  return proxyHermesRequest(request, "/lexware/settings");
+}
+
+export async function PUT(request: NextRequest) {
+  const originError = assertSameOrigin(request);
+
+  if (originError) {
+    return originError;
+  }
+
+  return proxyHermesRequest(request, "/lexware/settings");
+}

frontend/athena/app/api/lexware/test-connection/route.ts

@@ -0,0 +1,14 @@
+import { NextRequest } from "next/server";
+
+import { proxyHermesRequest } from "@/lib/server/hermes-proxy";
+import { assertSameOrigin } from "@/lib/server/request-guards";
+
+export async function POST(request: NextRequest) {
+  const originError = assertSameOrigin(request);
+
+  if (originError) {
+    return originError;
+  }
+
+  return proxyHermesRequest(request, "/lexware/test-connection");
+}

frontend/athena/app/api/repairs/[id]/estimates/[estimateId]/lexware/prepare-invoice/route.ts

@@ -0,0 +1,19 @@
+import { NextRequest } from "next/server";
+
+import { proxyHermesRequest } from "@/lib/server/hermes-proxy";
+import { assertSameOrigin } from "@/lib/server/request-guards";
+
+type Params = {
+  params: Promise<{ id: string; estimateId: string }>;
+};
+
+export async function POST(request: NextRequest, { params }: Params) {
+  const originError = assertSameOrigin(request);
+
+  if (originError) {
+    return originError;
+  }
+
+  const { id, estimateId } = await params;
+  return proxyHermesRequest(request, `/repairs/${id}/estimates/${estimateId}/lexware/prepare-invoice`);
+}

frontend/athena/app/repairs/[id]/page.tsx

@@ -176,6 +176,7 @@ export default function RepairDetailPage({ params }: Params) {
   const canDeleteEstimates = hasPermission(currentUser, "repair_estimates.delete");
   const canSendEstimates = hasPermission(currentUser, "repair_estimates.send");
   const canRevokeEstimates = hasPermission(currentUser, "repair_estimates.revoke");
+  const canLexwareExport = hasPermission(currentUser, "lexware.export");
 
   async function createPublicLink() {
     if (!repair || !canManagePublicLink) return;
@@ -444,6 +445,7 @@ export default function RepairDetailPage({ params }: Params) {
           canDelete={canDeleteEstimates}
           canSend={canSendEstimates}
           canRevoke={canRevokeEstimates}
+          canLexwareExport={canLexwareExport}
         />
       </DetailSection>
 

frontend/athena/app/settings/page.tsx

@@ -2,12 +2,17 @@
 
 import { useCallback, useEffect, useState } from "react";
 import type { ReactNode } from "react";
-import { ExternalLink, MailCheck, Save, Send, ShieldCheck } from "lucide-react";
+import { ExternalLink, MailCheck, ReceiptText, Save, Send, ShieldCheck } from "lucide-react";
 
 import { useToast } from "@/components/common/ToastProvider";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { api } from "@/lib/api";
+import type {
+  LexwareSettings,
+  LexwareSettingsPayload,
+  LexwareTestConnectionResponse,
+} from "@/types/lexware";
 import type {
   PublicLinksSettings,
   SettingsSource,
@@ -16,7 +21,7 @@ import type {
   SmtpTestResponse,
 } from "@/types/system-settings";
 
-type SettingsTab = "smtp" | "public-links";
+type SettingsTab = "smtp" | "public-links" | "lexware";
 
 const sourceLabels: Record<SettingsSource, string> = {
   database: "Admin-Konfiguration",
@@ -46,6 +51,18 @@ function emptySmtpSettings(): SmtpSettings {
   };
 }
 
+function emptyLexwareSettings(): LexwareSettings {
+  return {
+    enabled: false,
+    api_base_url: "https://api.lexware.io",
+    api_key_is_set: false,
+    organization_name: "",
+    default_tax_rate: "19.00",
+    default_payment_terms_days: 14,
+    source: "missing",
+  };
+}
+
 export default function SettingsPage() {
   const { showToast } = useToast();
   const [activeTab, setActiveTab] = useState<SettingsTab>("smtp");
@@ -56,22 +73,28 @@ export default function SettingsPage() {
     repair_status_base_url: "",
     source: "missing",
   });
+  const [lexware, setLexware] = useState<LexwareSettings>(emptyLexwareSettings());
+  const [newLexwareApiKey, setNewLexwareApiKey] = useState("");
   const [loading, setLoading] = useState(true);
   const [savingSmtp, setSavingSmtp] = useState(false);
   const [sendingTest, setSendingTest] = useState(false);
   const [savingPublicLinks, setSavingPublicLinks] = useState(false);
+  const [savingLexware, setSavingLexware] = useState(false);
+  const [testingLexware, setTestingLexware] = useState(false);
   const [error, setError] = useState("");
 
   const loadSettings = useCallback(async () => {
     setError("");
     setLoading(true);
     try {
-      const [smtpResponse, publicLinksResponse] = await Promise.all([
+      const [smtpResponse, publicLinksResponse, lexwareResponse] = await Promise.all([
         api.get<SmtpSettings>("/system-settings/smtp"),
         api.get<PublicLinksSettings>("/system-settings/public-links"),
+        api.get<LexwareSettings>("/lexware/settings"),
       ]);
       setSmtp(smtpResponse.data);
       setPublicLinks(publicLinksResponse.data);
+      setLexware(lexwareResponse.data);
     } catch (err) {
       setError(getErrorMessage(err, "Einstellungen konnten nicht geladen werden."));
     } finally {
@@ -158,6 +181,56 @@ export default function SettingsPage() {
     }
   }
 
+  async function saveLexware() {
+    setSavingLexware(true);
+    try {
+      const payload: LexwareSettingsPayload = {
+        enabled: lexware.enabled,
+        api_base_url: lexware.api_base_url,
+        organization_name: lexware.organization_name,
+        default_tax_rate: lexware.default_tax_rate,
+        default_payment_terms_days: lexware.default_payment_terms_days,
+      };
+
+      if (newLexwareApiKey) {
+        payload.api_key = newLexwareApiKey;
+      }
+
+      const response = await api.put<LexwareSettings>("/lexware/settings", payload);
+      setLexware(response.data);
+      setNewLexwareApiKey("");
+      showToast({ type: "success", title: "Lexware-Konfiguration gespeichert" });
+    } catch (err) {
+      showToast({
+        type: "error",
+        title: "Lexware konnte nicht gespeichert werden",
+        description: getErrorMessage(err, "Bitte prüfe die Lexware-Einstellungen."),
+      });
+    } finally {
+      setSavingLexware(false);
+    }
+  }
+
+  async function testLexwareConnection() {
+    setTestingLexware(true);
+    try {
+      const response = await api.post<LexwareTestConnectionResponse>("/lexware/test-connection");
+      showToast({
+        type: response.data.success ? "success" : "error",
+        title: response.data.success ? "Lexware-Verbindung erfolgreich" : "Lexware-Verbindung fehlgeschlagen",
+        description: response.data.message,
+      });
+    } catch (err) {
+      showToast({
+        type: "error",
+        title: "Lexware-Verbindung fehlgeschlagen",
+        description: getErrorMessage(err, "Die Verbindung konnte nicht geprüft werden."),
+      });
+    } finally {
+      setTestingLexware(false);
+    }
+  }
+
   if (loading) {
     return <div className="rounded-lg border bg-white p-8 text-slate-500">Einstellungen werden geladen...</div>;
   }
@@ -171,7 +244,7 @@ export default function SettingsPage() {
       <div className="flex flex-col gap-3 lg:flex-row lg:items-center lg:justify-between">
         <div>
           <h1 className="text-3xl font-bold text-slate-950">Einstellungen</h1>
-          <p className="mt-1 text-sm text-slate-500">SMTP-Versand und öffentliche Statuslinks verwalten</p>
+          <p className="mt-1 text-sm text-slate-500">SMTP-Versand, öffentliche Statuslinks und Lexware Office verwalten</p>
         </div>
         <div className="inline-flex w-fit rounded-lg border bg-white p-1">
           <TabButton active={activeTab === "smtp"} onClick={() => setActiveTab("smtp")}>
@@ -180,6 +253,9 @@ export default function SettingsPage() {
           <TabButton active={activeTab === "public-links"} onClick={() => setActiveTab("public-links")}>
             Öffentliche Links
           </TabButton>
+          <TabButton active={activeTab === "lexware"} onClick={() => setActiveTab("lexware")}>
+            Lexware Office
+          </TabButton>
         </div>
       </div>
 
@@ -287,7 +363,7 @@ export default function SettingsPage() {
             </div>
           </div>
         </section>
-      ) : (
+      ) : activeTab === "public-links" ? (
         <section className="rounded-lg border bg-white p-6">
           <div className="mb-6 flex flex-col gap-3 border-b pb-5 lg:flex-row lg:items-start lg:justify-between">
             <div>
@@ -319,6 +395,86 @@ export default function SettingsPage() {
             </p>
           </div>
         </section>
+      ) : (
+        <section className="rounded-lg border bg-white p-6">
+          <div className="mb-6 flex flex-col gap-3 border-b pb-5 lg:flex-row lg:items-start lg:justify-between">
+            <div>
+              <div className="flex items-center gap-2">
+                <ReceiptText className="h-5 w-5 text-slate-500" />
+                <h2 className="text-lg font-semibold text-slate-950">Lexware Office</h2>
+              </div>
+              <p className="mt-1 text-sm text-slate-500">
+                Quelle: {sourceLabels[lexware.source]}
+                {lexware.api_key_is_set ? " · API-Key ist gesetzt" : ""}
+              </p>
+            </div>
+            <div className="flex flex-wrap gap-2">
+              <Button type="button" variant="outline" onClick={() => void testLexwareConnection()} disabled={testingLexware}>
+                <ShieldCheck />
+                {testingLexware ? "Prüft..." : "Verbindung testen"}
+              </Button>
+              <Button type="button" onClick={() => void saveLexware()} disabled={savingLexware}>
+                <Save />
+                {savingLexware ? "Speichert..." : "Speichern"}
+              </Button>
+            </div>
+          </div>
+
+          <div className="grid gap-5 lg:grid-cols-2">
+            <label className="flex items-center gap-3 rounded-lg border p-4 text-sm font-medium text-slate-800">
+              <input
+                type="checkbox"
+                className="h-4 w-4 rounded border-slate-300"
+                checked={lexware.enabled}
+                onChange={(event) => setLexware((current) => ({ ...current, enabled: event.target.checked }))}
+              />
+              Lexware-Integration aktivieren
+            </label>
+
+            <Field label="Organisation">
+              <Input value={lexware.organization_name} onChange={(event) => setLexware((current) => ({ ...current, organization_name: event.target.value }))} />
+            </Field>
+
+            <Field label="API Base URL">
+              <Input value={lexware.api_base_url} onChange={(event) => setLexware((current) => ({ ...current, api_base_url: event.target.value }))} />
+            </Field>
+
+            <Field label={lexware.api_key_is_set ? "Neuen API-Key setzen" : "API-Key"}>
+              <Input
+                type="password"
+                value={newLexwareApiKey}
+                placeholder={lexware.api_key_is_set ? "Leer lassen, um aktuellen API-Key zu behalten" : ""}
+                onChange={(event) => setNewLexwareApiKey(event.target.value)}
+              />
+            </Field>
+
+            <Field label="Standard MwSt. %">
+              <Input
+                inputMode="decimal"
+                value={lexware.default_tax_rate}
+                onChange={(event) => setLexware((current) => ({ ...current, default_tax_rate: event.target.value }))}
+              />
+            </Field>
+
+            <Field label="Zahlungsziel Tage">
+              <Input
+                type="number"
+                min={0}
+                max={365}
+                value={lexware.default_payment_terms_days}
+                onChange={(event) => setLexware((current) => ({ ...current, default_payment_terms_days: Number(event.target.value) || 0 }))}
+              />
+            </Field>
+          </div>
+
+          <div className="mt-5 flex items-start gap-3 rounded-lg border border-blue-100 bg-blue-50 p-4 text-sm text-blue-950">
+            <ShieldCheck className="mt-0.5 h-5 w-5 shrink-0" />
+            <p>
+              Olympus bereitet Werkstatt- und KV-Daten vor. Lexware Office bleibt führend für Buchhaltung,
+              Rechnungen, Steuer und DATEV/EÜR. Der API-Key wird nicht angezeigt und nicht an den Browser zurückgegeben.
+            </p>
+          </div>
+        </section>
       )}
     </div>
   );