Merge pull request #154 from Since-3/feature/notification-system

added in-app notification system

prisma/migrations/20260828160127_add_notifications/migration.sql

@@ -0,0 +1,22 @@
+-- AlterTable
+ALTER TABLE "Business" ADD COLUMN     "notificationSettings" JSONB;
+
+-- CreateTable
+CREATE TABLE "Notification" (
+    "id" TEXT NOT NULL,
+    "recipientId" TEXT NOT NULL,
+    "type" TEXT NOT NULL,
+    "title" TEXT NOT NULL,
+    "body" TEXT NOT NULL,
+    "linkUrl" TEXT,
+    "readAt" TIMESTAMP(3),
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+
+    CONSTRAINT "Notification_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateIndex
+CREATE INDEX "Notification_recipientId_readAt_idx" ON "Notification"("recipientId", "readAt");
+
+-- CreateIndex
+CREATE INDEX "Notification_recipientId_createdAt_idx" ON "Notification"("recipientId", "createdAt");

prisma/schema.prisma

@@ -97,27 +97,28 @@ model Manager {
 }
 
 model Business {
-  id                  String   @id @default(uuid())
+  id                   String   @id @default(uuid())
-  managerId           String
+  managerId            String
-  name                String
+  name                 String
-  address             String
+  address              String
-  email               String
+  email                String
-  title               String
+  title                String
-  ustId               String?
+  ustId                String?
-  banking             String?
+  banking              String?
-  plan                String?
+  plan                 String?
-  subscription        Json?
+  subscription         Json?
-  slug                String?  @unique
+  slug                 String?  @unique
-  isPublic            Boolean  @default(false)
+  isPublic             Boolean  @default(false)
-  stripeAccountId     String?  @unique // Stripe Connect Account ID
+  stripeAccountId      String?  @unique // Stripe Connect Account ID
-  stripeAccountStatus String? // "pending" | "active" | "restricted"
+  stripeAccountStatus  String? // "pending" | "active" | "restricted"
-  invoiceCounter      Int      @default(0) // Fortlaufender Zähler für Rechnungsnummern
+  invoiceCounter       Int      @default(0) // Fortlaufender Zähler für Rechnungsnummern
-  cancellationPolicy  Json? // { tiers: [{ hoursBeforeStart: number, refundPercent: number }, ...] }, absteigend sortiert. null = immer 100% Rückerstattung.
+  cancellationPolicy   Json? // { tiers: [{ hoursBeforeStart: number, refundPercent: number }, ...] }, absteigend sortiert. null = immer 100% Rückerstattung.
-  branding            Json? // { companyName, logoUrl, primaryColor, accentColor }. null = Kumasy-Standardbranding (siehe KUMASY_BRANDING).
+  branding             Json? // { companyName, logoUrl, primaryColor, accentColor }. null = Kumasy-Standardbranding (siehe KUMASY_BRANDING).
-  manager             Manager  @relation(fields: [managerId], references: [id])
+  notificationSettings Json? // { "booking.created": true, ... } Opt-out pro In-App-Benachrichtigungstyp. null / fehlender Key = Registry-Default (siehe NOTIFICATION_TYPES).
-  courses             Course[]
+  manager              Manager  @relation(fields: [managerId], references: [id])
-  createdAt           DateTime @default(now())
+  courses              Course[]
-  updatedAt           DateTime @updatedAt
+  createdAt            DateTime @default(now())
+  updatedAt            DateTime @updatedAt
 
   @@index([managerId])
 }
@@ -225,3 +226,22 @@ model CourseWaitlistEntry {
   @@index([courseId])
   @@index([userId])
 }
+
+// In-App-Benachrichtigungen für die Studio-Seite (Manager/Employee).
+// recipientId ist bewusst polymorph ohne Relation (wie Employee.createdBy /
+// CourseBooking.cancelledBy): Empfänger kann je nach Typ Manager oder Employee
+// sein, perspektivisch auch User. Keine FK, damit kein Modell-Join nötig ist
+// und ein späterer Kunden-Empfänger keine Migration braucht.
+model Notification {
+  id          String    @id @default(uuid())
+  recipientId String // Manager- oder Employee-ID
+  type        String // Schlüssel aus NOTIFICATION_TYPES (src/modules/notifications/lib/notification-types.ts)
+  title       String
+  body        String
+  linkUrl     String? // Ziel beim Klick, z.B. /courses/edit/<id>
+  readAt      DateTime? // null = ungelesen
+  createdAt   DateTime  @default(now())
+
+  @@index([recipientId, readAt])
+  @@index([recipientId, createdAt])
+}

src/app/(main)/settings/notifications/page.tsx

@@ -1,13 +1,32 @@
 import { Suspense } from "react";
+import { AlertTriangle } from "lucide-react";
 import { requireManager } from "@/src/lib/auth/getUser";
+import { getNotificationSettings } from "@/src/modules/settings/actions/notification-settings-actions";
+import { resolveNotificationSettings } from "@/src/modules/notifications/lib/notification-types";
 import SettingsNotificationPageView from "@/src/modules/settings/ui/views/settings-notification-page-view";
 import SettingsLoading from "../loading";
 
 export default async function SettingsNotificationPage() {
-  await requireManager();
+  const manager = await requireManager();
+  const businesses = manager.businesses.map((b) => ({ id: b.id, name: b.name }));
+
+  const firstBusinessId = businesses[0]?.id;
+  const result = firstBusinessId ? await getNotificationSettings(firstBusinessId) : null;
+
+  if (firstBusinessId && !result?.success) {
+    return (
+      <div className="flex gap-2 text-sm bg-red-50 border border-red-200 rounded-lg p-4 text-red-700">
+        <AlertTriangle size={16} className="shrink-0 mt-0.5" />
+        <p>{result?.error ?? "Benachrichtigungseinstellungen konnten nicht geladen werden."}</p>
+      </div>
+    );
+  }
+
+  const initialSettings = result?.success ? result.settings : resolveNotificationSettings(null);
+
   return (
     <Suspense fallback={<SettingsLoading />}>
-      <SettingsNotificationPageView />
+      <SettingsNotificationPageView businesses={businesses} initialSettings={initialSettings} />
     </Suspense>
   );
 }

src/app/api/stripe/webhook/route.ts

@@ -11,6 +11,7 @@ import {
   type BookingRefundReason,
 } from "@/src/lib/mail/templates/booking-refund";
 import { toEmailBranding } from "@/src/modules/settings/lib/to-email-branding";
+import { notifyBusinessManager } from "@/src/modules/notifications/lib/create-notification";
 
 /**
  * Sucht einen registrierten User anhand der E-Mail, case-insensitive.
@@ -315,6 +316,19 @@ async function handleCheckoutCompleted(session: Stripe.Checkout.Session) {
     await removeFromWaitlistIfPresent(courseId, outcome.bookingId).catch((err) =>
       console.error("Warteliste-Aufräumen fehlgeschlagen:", err)
     );
+
+    // In-App-Benachrichtigung ans Studio - blockiert den Webhook nicht.
+    const customerLabel =
+      session.customer_details?.name?.trim() ||
+      session.customer_email ||
+      session.customer_details?.email ||
+      "Ein Kunde";
+    await withTimeout(
+      notifyManagerOfBooking(courseId, customerLabel).catch((err) =>
+        console.error("Buchungs-Benachrichtigung fehlgeschlagen:", err)
+      ),
+      2000
+    );
   }
 
   revalidatePath("/courses");
@@ -678,6 +692,46 @@ async function removeFromWaitlistIfPresent(courseId: string, bookingId: string):
   await prisma.courseWaitlistEntry.deleteMany({ where: { courseId, userId: booking.userId } });
 }
 
+/**
+ * Legt für den Studio-Manager eine In-App-Benachrichtigung über eine neue,
+ * bezahlte Buchung an - und zusätzlich eine "Kurs ausgebucht"-Benachrichtigung,
+ * falls diese Buchung den Kurs gefüllt hat. Wirft nie (notifyBusinessManager
+ * kapselt alle Fehler), der Aufrufer hängt zusätzlich ein .catch daran.
+ */
+async function notifyManagerOfBooking(courseId: string, customerLabel: string): Promise<void> {
+  const course = await prisma.course.findUnique({
+    where: { id: courseId },
+    select: { name: true, date: true, businessId: true, maxParticipants: true },
+  });
+  if (!course?.businessId) return;
+
+  const courseDate = course.date.toLocaleDateString("de-DE", {
+    day: "numeric",
+    month: "long",
+    timeZone: "Europe/Berlin",
+  });
+  const linkUrl = `/courses/edit/${courseId}`;
+
+  await notifyBusinessManager(course.businessId, {
+    type: "booking.created",
+    title: `Neue Buchung: ${course.name}`,
+    body: `${customerLabel} hat sich für den ${courseDate} angemeldet.`,
+    linkUrl,
+  });
+
+  const paidCount = await prisma.courseBooking.count({
+    where: { courseId, paymentStatus: "paid" },
+  });
+  if (paidCount >= course.maxParticipants) {
+    await notifyBusinessManager(course.businessId, {
+      type: "course.full",
+      title: `Kurs ausgebucht: ${course.name}`,
+      body: `Der Kurs am ${courseDate} hat mit ${paidCount} Teilnehmern die maximale Kapazität erreicht.`,
+      linkUrl,
+    });
+  }
+}
+
 async function sendBookingRefund(
   recipientEmail: string,
   courseId: string,

src/modules/courses/actions/cancel-booking-shared.ts

@@ -5,6 +5,7 @@ import { generateBookingRefundEmail } from "@/src/lib/mail/templates/booking-ref
 import { combineDateAndTime, calculateRefundAmountCents } from "./cancellation-policy";
 import { toEmailBranding } from "@/src/modules/settings/lib/to-email-branding";
 import { notifyCourseWaitlist } from "./notify-waitlist";
+import { notifyBusinessManager } from "@/src/modules/notifications/lib/create-notification";
 
 export type CancelBookingResult =
   | { success: true; refundedAmountCents: number; refundPercent: number }
@@ -235,6 +236,35 @@ export async function executeBookingCancellation(
   ).catch((err) => console.error("Storno-Mail fehlgeschlagen:", err));
   await withTimeout(emailPromise, 2000);
 
+  // In-App-Benachrichtigung ans Studio nur bei einer echten Selbst-Stornierung
+  // durch den Kunden. Manager-initiierte Stornos (cancelledBy === "manager")
+  // und der forceFullRefund-Pfad der Kurs-weiten Absage lösen hier bewusst
+  // nichts aus - für Letztere gibt es eine eigene "course.cancelled"-
+  // Benachrichtigung in executeCourseCancellation.
+  if (cancelledBy === "user" && !forceFullRefund) {
+    const notifyPromise = (async () => {
+      const customer = booking.userId
+        ? await prisma.user.findUnique({
+            where: { id: booking.userId },
+            select: { name: true, email: true },
+          })
+        : null;
+      const customerLabel = customer?.name || customer?.email || "Ein Kunde";
+      const courseDate = booking.course.date.toLocaleDateString("de-DE", {
+        day: "numeric",
+        month: "long",
+        timeZone: "Europe/Berlin",
+      });
+      await notifyBusinessManager(booking.course.businessId, {
+        type: "booking.cancelled",
+        title: `Stornierung: ${booking.course.name}`,
+        body: `${customerLabel} hat die Buchung für den ${courseDate} storniert.`,
+        linkUrl: `/courses/edit/${booking.course.id}`,
+      });
+    })().catch((err) => console.error("Storno-Benachrichtigung fehlgeschlagen:", err));
+    await withTimeout(notifyPromise, 2000);
+  }
+
   // Ein frei gewordener Platz soll allen Wartelisten-Einträgen des Kurses
   // gemeldet werden - notifyCourseWaitlist prüft selbst frisch, ob der Kurs
   // noch veröffentlicht ist (bricht bei einer Kurs-weiten Absage von selbst ab).

src/modules/courses/actions/cancel-course-shared.ts

@@ -4,6 +4,7 @@ import { prisma } from "@/src/lib/prisma";
 import { getUserData, isManager, isEmployee, getEffectiveManagerId } from "@/src/lib/auth/getUser";
 import { revalidatePath, revalidateTag } from "next/cache";
 import { executeBookingCancellation } from "./cancel-booking-shared";
+import { notifyBusinessManager } from "@/src/modules/notifications/lib/create-notification";
 
 const COURSE_CANCELLATION_REASON = "Kurs abgesagt";
 
@@ -89,6 +90,11 @@ async function executeCourseCancellation(courseId: string): Promise<CourseCancel
     data: { status: "cancelled", cancelledAt: new Date() },
   });
 
+  const course = await prisma.course.findUnique({
+    where: { id: courseId },
+    select: { name: true, date: true, businessId: true },
+  });
+
   const bookings = await prisma.courseBooking.findMany({
     where: { courseId, paymentStatus: "paid" },
     select: { id: true, userId: true },
@@ -124,6 +130,33 @@ async function executeCourseCancellation(courseId: string): Promise<CourseCancel
 
   revalidatePath("/courses");
 
+  // In-App-Benachrichtigung ans Studio, dass der Termin abgesagt wurde und
+  // wie viele Buchungen erstattet wurden. Fehler hier dürfen das Ergebnis der
+  // Absage nicht beeinflussen (notifyBusinessManager wirft ohnehin nie).
+  if (course?.businessId) {
+    const courseDate = course.date.toLocaleDateString("de-DE", {
+      day: "numeric",
+      month: "long",
+      timeZone: "Europe/Berlin",
+    });
+    const refundInfo =
+      cancelled > 0
+        ? `${cancelled} Buchung${cancelled === 1 ? "" : "en"} wurde${
+            cancelled === 1 ? "" : "n"
+          } storniert und erstattet.`
+        : "Es waren keine bezahlten Buchungen betroffen.";
+    await notifyBusinessManager(course.businessId, {
+      type: "course.cancelled",
+      title: `Kurs abgesagt: ${course.name}`,
+      body: `Der Termin am ${courseDate} wurde abgesagt. ${refundInfo}${
+        failed > 0
+          ? ` ${failed} Erstattung(en) fehlgeschlagen – bitte im Stripe-Dashboard prüfen.`
+          : ""
+      }`,
+      linkUrl: `/courses/edit/${courseId}`,
+    });
+  }
+
   return { success: true, cancelled, failed, errors };
 }
 

src/modules/courses/actions/notify-waitlist.ts

@@ -20,6 +20,7 @@ import { prisma } from "@/src/lib/prisma";
 import { sendMail } from "@/src/lib/mail/resend";
 import { generateWaitlistSpotAvailableEmail } from "@/src/lib/mail/templates/waitlist-spot-available";
 import { toEmailBranding } from "@/src/modules/settings/lib/to-email-branding";
+import { notifyBusinessManager } from "@/src/modules/notifications/lib/create-notification";
 
 export async function notifyCourseWaitlist(courseId: string): Promise<void> {
   // Kurs frisch nachladen statt einem durchgereichten Flag zu vertrauen -
@@ -31,7 +32,7 @@ export async function notifyCourseWaitlist(courseId: string): Promise<void> {
     select: {
       status: true,
       name: true,
-      business: { select: { name: true, branding: true, slug: true } },
+      business: { select: { id: true, name: true, branding: true, slug: true } },
     },
   });
 
@@ -86,7 +87,7 @@ export async function notifyCourseWaitlist(courseId: string): Promise<void> {
 
   // Promise.allSettled statt Promise.all - ein fehlgeschlagener Versand
   // (z.B. ungültige/inaktive Adresse) soll die anderen Empfänger nicht blockieren.
-  await Promise.allSettled(
+  const results = await Promise.allSettled(
     recipients.map(async (r) => {
       const result = await sendMail({ to: r.email, subject, html, text });
       // notifiedAt nur bei tatsächlich erfolgreichem Versand setzen - sonst
@@ -99,9 +100,25 @@ export async function notifyCourseWaitlist(courseId: string): Promise<void> {
           where: { id: r.entryId },
           data: { notifiedAt: new Date() },
         });
-      } else {
+        return true;
-        console.error(`Wartelisten-Mail an ${r.email} fehlgeschlagen:`, result.error);
       }
+      console.error(`Wartelisten-Mail an ${r.email} fehlgeschlagen:`, result.error);
+      return false;
     })
   );
+
+  // In-App-Benachrichtigung ans Studio: wie viele Wartende wurden über den
+  // frei gewordenen Platz informiert. Wirft nie und läuft nach dem Fan-out,
+  // damit ein präziser Zähler zur Verfügung steht.
+  const notifiedCount = results.filter((r) => r.status === "fulfilled" && r.value === true).length;
+  if (notifiedCount > 0) {
+    await notifyBusinessManager(course.business.id, {
+      type: "waitlist.spot",
+      title: `Wartelisten-Platz frei: ${course.name}`,
+      body: `Ein Platz ist frei geworden. ${notifiedCount} Wartende${
+        notifiedCount === 1 ? "r wurde" : " wurden"
+      } benachrichtigt – wer zuerst bucht, bekommt den Platz.`,
+      linkUrl: `/courses/edit/${courseId}`,
+    });
+  }
 }

src/modules/dashboard/ui/components/DashboardNavbar.tsx

@@ -4,6 +4,7 @@ import { Button } from "@/src/components/ui/button";
 import { useSidebar } from "@/src/components/ui/sidebar";
 import { PanelLeftCloseIcon, PanelLeftIcon } from "lucide-react";
 import { usePathname } from "next/navigation";
+import NotificationBell from "@/src/modules/notifications/ui/components/NotificationBell";
 
 const menuTitles: Record<string, string> = {
   "/dashboard": "Dashboard",
@@ -69,6 +70,10 @@ const DashboardNavbar = () => {
         <div className="w-px h-6 bg-border" />
 
         <h1 className="text-xl font-semibold mt-1">{pageTitle}</h1>
+
+        <div className="ml-auto">
+          <NotificationBell />
+        </div>
       </div>
     </div>
   );

src/modules/notifications/actions/notification-actions.ts

@@ -0,0 +1,121 @@
+"use server";
+
+import { prisma } from "@/src/lib/prisma";
+import { requireAuthWithData, isManager, isEmployee } from "@/src/lib/auth/getUser";
+import type { NotificationType } from "../lib/notification-types";
+
+const MAX_ITEMS = 20;
+
+export interface NotificationDTO {
+  id: string;
+  type: NotificationType;
+  title: string;
+  body: string;
+  linkUrl: string | null;
+  readAt: string | null;
+  createdAt: string;
+}
+
+export interface GetNotificationsResult {
+  items: NotificationDTO[];
+  unreadCount: number;
+}
+
+const EMPTY: GetNotificationsResult = { items: [], unreadCount: 0 };
+
+/**
+ * Lädt die letzten Benachrichtigungen des eingeloggten Nutzers plus die
+ * Anzahl ungelesener. Nur die Studio-Seite (Manager/Employee) hat ein
+ * Notification-Center - für die User-Rolle (oder ohne Session) wird bewusst
+ * ein leeres Ergebnis zurückgegeben, damit die Bell-Komponente ohne
+ * Sonderfall gerendert werden kann.
+ */
+export async function getNotifications(): Promise<GetNotificationsResult> {
+  let userData;
+  try {
+    userData = await requireAuthWithData();
+  } catch {
+    return EMPTY;
+  }
+
+  if (!isManager(userData) && !isEmployee(userData)) return EMPTY;
+
+  try {
+    const [items, unreadCount] = await Promise.all([
+      prisma.notification.findMany({
+        where: { recipientId: userData.id },
+        orderBy: { createdAt: "desc" },
+        take: MAX_ITEMS,
+      }),
+      prisma.notification.count({
+        where: { recipientId: userData.id, readAt: null },
+      }),
+    ]);
+
+    return {
+      items: items.map((n) => ({
+        id: n.id,
+        type: n.type as NotificationType,
+        title: n.title,
+        body: n.body,
+        linkUrl: n.linkUrl,
+        readAt: n.readAt?.toISOString() ?? null,
+        createdAt: n.createdAt.toISOString(),
+      })),
+      unreadCount,
+    };
+  } catch (error) {
+    console.error("getNotifications fehlgeschlagen:", error);
+    return EMPTY;
+  }
+}
+
+/**
+ * Markiert eine einzelne Benachrichtigung als gelesen. Die recipientId steht
+ * in der WHERE-Bedingung (updateMany), damit niemand fremde Benachrichtigungen
+ * manipulieren kann - ein Treffer 0 ist kein Fehler.
+ */
+export async function markNotificationRead(id: string): Promise<{ success: boolean }> {
+  let userData;
+  try {
+    userData = await requireAuthWithData();
+  } catch {
+    return { success: false };
+  }
+  if (!isManager(userData) && !isEmployee(userData)) return { success: false };
+
+  try {
+    await prisma.notification.updateMany({
+      where: { id, recipientId: userData.id, readAt: null },
+      data: { readAt: new Date() },
+    });
+    return { success: true };
+  } catch (error) {
+    console.error("markNotificationRead fehlgeschlagen:", error);
+    return { success: false };
+  }
+}
+
+/**
+ * Markiert alle ungelesenen Benachrichtigungen des Nutzers als gelesen.
+ */
+export async function markAllNotificationsRead(): Promise<{ success: boolean }> {
+  let userData;
+  try {
+    userData = await requireAuthWithData();
+  } catch {
+    return { success: false };
+  }
+  if (!isManager(userData) && !isEmployee(userData)) return { success: false };
+
+  try {
+    await prisma.notification.updateMany({
+      where: { recipientId: userData.id, readAt: null },
+      data: { readAt: new Date() },
+    });
+    return { success: true };
+  } catch (error) {
+    console.error("markAllNotificationsRead fehlgeschlagen:", error);
+    return { success: false };
+  }
+}

src/modules/notifications/lib/create-notification.ts

@@ -0,0 +1,102 @@
+/**
+ * Kern-Helfer zum Erzeugen von In-App-Benachrichtigungen.
+ *
+ * Prinzipien:
+ *  - Wirft NIE. Ein fehlgeschlagenes Insert (DB weg, o.ä.) darf niemals eine
+ *    Buchung, Stornierung oder Kursabsage kippen. Alles in try/catch, Fehler
+ *    landen nur im Log - gleiches Pattern wie der Mailversand.
+ *  - Respektiert die pro-Business-Opt-outs aus Business.notificationSettings,
+ *    wenn ein businessId übergeben wird. Ohne businessId (kein Business-Kontext)
+ *    wird immer zugestellt.
+ *  - Empfänger ist die Manager-ID des Business (kein Employee-Fanout im MVP).
+ */
+
+import { prisma } from "@/src/lib/prisma";
+import {
+  NOTIFICATION_TYPES,
+  resolveNotificationSettings,
+  type NotificationType,
+} from "./notification-types";
+
+interface CreateNotificationInput {
+  recipientId: string;
+  type: NotificationType;
+  title: string;
+  body: string;
+  linkUrl?: string;
+}
+
+/**
+ * Prüft, ob ein Benachrichtigungstyp für ein Business aktiv ist.
+ * Fällt bei fehlendem Business / fehlendem Key auf den Registry-Default zurück.
+ */
+export async function isNotificationEnabled(
+  businessId: string,
+  type: NotificationType
+): Promise<boolean> {
+  try {
+    const business = await prisma.business.findUnique({
+      where: { id: businessId },
+      select: { notificationSettings: true },
+    });
+    if (!business) return NOTIFICATION_TYPES[type].defaultOn;
+    return resolveNotificationSettings(business.notificationSettings)[type];
+  } catch (error) {
+    console.error("isNotificationEnabled fehlgeschlagen:", error);
+    // Im Zweifel zustellen - eine verpasste Benachrichtigung ist schlimmer
+    // als eine, die trotz Opt-out durchrutscht.
+    return NOTIFICATION_TYPES[type].defaultOn;
+  }
+}
+
+/**
+ * Legt eine einzelne Benachrichtigung an. Gibt true zurück, wenn ein Datensatz
+ * geschrieben wurde, false wenn übersprungen (Opt-out) oder fehlgeschlagen.
+ */
+export async function createNotification(input: CreateNotificationInput): Promise<boolean> {
+  try {
+    await prisma.notification.create({
+      data: {
+        recipientId: input.recipientId,
+        type: input.type,
+        title: input.title,
+        body: input.body,
+        linkUrl: input.linkUrl ?? null,
+      },
+    });
+    return true;
+  } catch (error) {
+    console.error("createNotification fehlgeschlagen:", error);
+    return false;
+  }
+}
+
+/**
+ * Legt eine Benachrichtigung für den Manager eines Business an - sofern der
+ * Typ für dieses Business nicht abgeschaltet wurde.
+ *
+ * Bewusst fire-and-forget-tauglich: Rückgabe wird von den Aufrufern (Webhook,
+ * Storno-Action, ...) nicht ausgewertet, der Aufruf hängt an einem
+ * .catch(console.error) und blockiert den Request nicht.
+ */
+export async function notifyBusinessManager(
+  businessId: string | null | undefined,
+  input: Omit<CreateNotificationInput, "recipientId">
+): Promise<void> {
+  try {
+    if (!businessId) return;
+
+    const business = await prisma.business.findUnique({
+      where: { id: businessId },
+      select: { managerId: true, notificationSettings: true },
+    });
+    if (!business) return;
+
+    const enabled = resolveNotificationSettings(business.notificationSettings)[input.type];
+    if (!enabled) return;
+
+    await createNotification({ ...input, recipientId: business.managerId });
+  } catch (error) {
+    console.error("notifyBusinessManager fehlgeschlagen:", error);
+  }
+}

src/modules/notifications/lib/notification-types.ts

@@ -0,0 +1,92 @@
+/**
+ * Registry aller In-App-Benachrichtigungstypen.
+ *
+ * Single Source of Truth für:
+ *  - welche Typen es gibt (Schlüssel)
+ *  - Anzeigelabel + Kurzbeschreibung in den Einstellungen
+ *  - Icon (lucide-react Komponentenname, wird in NotificationItem/Settings gemappt)
+ *  - defaultOn: ob der Typ ohne explizite Einstellung aktiv ist
+ *  - audience: an wen der Typ gerichtet ist (aktuell nur "studio" = Manager)
+ *
+ * Ein neuer Typ wird ausschließlich hier ergänzt; Einstellungen-UI, Zod-
+ * Validierung und createNotification leiten sich daraus ab.
+ */
+
+export type NotificationAudience = "studio";
+
+export interface NotificationTypeDef {
+  label: string;
+  description: string;
+  /** lucide-react Icon-Komponentenname */
+  icon: string;
+  defaultOn: boolean;
+  audience: NotificationAudience;
+}
+
+export const NOTIFICATION_TYPES = {
+  "booking.created": {
+    label: "Neue Buchung",
+    description: "Ein Kunde hat einen Platz in einem deiner Kurse gebucht.",
+    icon: "CalendarPlus",
+    defaultOn: true,
+    audience: "studio",
+  },
+  "booking.cancelled": {
+    label: "Stornierung durch Kunde",
+    description: "Ein Kunde hat seine Buchung selbst storniert.",
+    icon: "CalendarX",
+    defaultOn: true,
+    audience: "studio",
+  },
+  "course.full": {
+    label: "Kurs ausgebucht",
+    description: "Ein Kurs hat seine maximale Teilnehmerzahl erreicht.",
+    icon: "Users",
+    defaultOn: true,
+    audience: "studio",
+  },
+  "course.cancelled": {
+    label: "Kurs abgesagt",
+    description: "Ein kompletter Kurstermin wurde abgesagt und alle Buchungen erstattet.",
+    icon: "Ban",
+    defaultOn: true,
+    audience: "studio",
+  },
+  "waitlist.spot": {
+    label: "Wartelisten-Platz frei",
+    description:
+      "In einem ausgebuchten Kurs ist ein Platz frei geworden und die Warteliste wurde benachrichtigt.",
+    icon: "BellRing",
+    defaultOn: true,
+    audience: "studio",
+  },
+} as const satisfies Record<string, NotificationTypeDef>;
+
+export type NotificationType = keyof typeof NOTIFICATION_TYPES;
+
+export const NOTIFICATION_TYPE_KEYS = Object.keys(NOTIFICATION_TYPES) as NotificationType[];
+
+export function isNotificationType(value: string): value is NotificationType {
+  // Object.hasOwn statt `in`: schließt geerbte Namen wie "__proto__" oder
+  // "constructor" aus, die sonst als gültige Typen durchrutschen würden.
+  return Object.hasOwn(NOTIFICATION_TYPES, value);
+}
+
+/**
+ * Merged gespeicherte Einstellungen (Business.notificationSettings, evtl. null
+ * oder unvollständig) über die Registry-Defaults zu einer vollständigen Map.
+ * Unbekannte Keys im gespeicherten Wert werden ignoriert.
+ */
+export function resolveNotificationSettings(stored: unknown): Record<NotificationType, boolean> {
+  const storedRecord =
+    stored && typeof stored === "object" && !Array.isArray(stored)
+      ? (stored as Record<string, unknown>)
+      : {};
+
+  const result = {} as Record<NotificationType, boolean>;
+  for (const key of NOTIFICATION_TYPE_KEYS) {
+    const value = Object.hasOwn(storedRecord, key) ? storedRecord[key] : undefined;
+    result[key] = typeof value === "boolean" ? value : NOTIFICATION_TYPES[key].defaultOn;
+  }
+  return result;
+}

src/modules/notifications/ui/components/NotificationBell.tsx

@@ -0,0 +1,138 @@
+"use client";
+
+import { useCallback, useEffect, useState, useTransition } from "react";
+import { useRouter, usePathname } from "next/navigation";
+import { Bell, CheckCheck } from "lucide-react";
+import { Popover, PopoverContent, PopoverTrigger } from "@/src/components/ui/popover";
+import { Button } from "@/src/components/ui/button";
+import { cn } from "@/src/lib/utils";
+import {
+  getNotifications,
+  markNotificationRead,
+  markAllNotificationsRead,
+  type NotificationDTO,
+} from "../../actions/notification-actions";
+import NotificationItem from "./NotificationItem";
+
+const NotificationBell = () => {
+  const router = useRouter();
+  const pathname = usePathname();
+  const [items, setItems] = useState<NotificationDTO[]>([]);
+  const [unreadCount, setUnreadCount] = useState(0);
+  const [open, setOpen] = useState(false);
+  const [loaded, setLoaded] = useState(false);
+  const [, startTransition] = useTransition();
+
+  const refresh = useCallback(async () => {
+    const result = await getNotifications();
+    setItems(result.items);
+    setUnreadCount(result.unreadCount);
+    setLoaded(true);
+  }, []);
+
+  // Erstladen + Refetch bei jedem Seitenwechsel (kein Hintergrund-Polling).
+  // Das setState läuft erst nach dem await, nicht synchron im Effect-Body -
+  // gleiches Muster wie CancelBookingConfirmDialog.
+  useEffect(() => {
+    let cancelled = false;
+    (async () => {
+      const result = await getNotifications();
+      if (cancelled) return;
+      setItems(result.items);
+      setUnreadCount(result.unreadCount);
+      setLoaded(true);
+    })();
+    return () => {
+      cancelled = true;
+    };
+  }, [pathname]);
+
+  const handleOpenChange = (next: boolean) => {
+    setOpen(next);
+    if (next) void refresh();
+  };
+
+  const handleSelect = (notification: NotificationDTO) => {
+    if (notification.readAt === null) {
+      // Optimistisch als gelesen markieren.
+      setItems((prev) =>
+        prev.map((n) => (n.id === notification.id ? { ...n, readAt: new Date().toISOString() } : n))
+      );
+      setUnreadCount((c) => Math.max(0, c - 1));
+      startTransition(async () => {
+        await markNotificationRead(notification.id);
+      });
+    }
+    setOpen(false);
+    if (notification.linkUrl) router.push(notification.linkUrl);
+  };
+
+  const handleMarkAll = () => {
+    setItems((prev) => prev.map((n) => ({ ...n, readAt: n.readAt ?? new Date().toISOString() })));
+    setUnreadCount(0);
+    startTransition(async () => {
+      await markAllNotificationsRead();
+    });
+  };
+
+  const badgeLabel = unreadCount > 99 ? "99+" : String(unreadCount);
+
+  return (
+    <Popover open={open} onOpenChange={handleOpenChange}>
+      <PopoverTrigger asChild>
+        <Button
+          variant="outline"
+          size="icon"
+          className="relative size-9 cursor-pointer"
+          aria-label={
+            unreadCount > 0 ? `Benachrichtigungen, ${unreadCount} ungelesen` : "Benachrichtigungen"
+          }
+        >
+          <Bell className="size-4" />
+          {unreadCount > 0 && (
+            <span className="absolute -right-1 -top-1 flex min-w-4 items-center justify-center rounded-full bg-destructive px-1 text-[10px] font-semibold leading-4 text-white">
+              {badgeLabel}
+            </span>
+          )}
+        </Button>
+      </PopoverTrigger>
+
+      <PopoverContent align="end" sideOffset={8} className="w-88 p-0">
+        <div className="flex items-center justify-between border-b px-4 py-3">
+          <span className="text-sm font-semibold">Benachrichtigungen</span>
+          {unreadCount > 0 && (
+            <button
+              type="button"
+              onClick={handleMarkAll}
+              className="flex items-center gap-1 text-xs text-muted-foreground transition-colors hover:text-foreground"
+            >
+              <CheckCheck className="size-3.5" />
+              Alle gelesen
+            </button>
+          )}
+        </div>
+
+        <div className="max-h-96 overflow-y-auto">
+          {!loaded ? (
+            <p className="px-4 py-10 text-center text-sm text-muted-foreground">Lädt …</p>
+          ) : items.length === 0 ? (
+            <div className="px-4 py-12 text-center">
+              <Bell className="mx-auto size-6 text-muted-foreground/40" />
+              <p className="mt-2 text-sm text-muted-foreground">Keine Benachrichtigungen</p>
+            </div>
+          ) : (
+            <ul className={cn("divide-y")}>
+              {items.map((n) => (
+                <li key={n.id}>
+                  <NotificationItem notification={n} onSelect={handleSelect} />
+                </li>
+              ))}
+            </ul>
+          )}
+        </div>
+      </PopoverContent>
+    </Popover>
+  );
+};
+
+export default NotificationBell;

src/modules/notifications/ui/components/NotificationItem.tsx

@@ -0,0 +1,62 @@
+"use client";
+
+import { formatDistanceToNow } from "date-fns";
+import { de } from "date-fns/locale";
+import { cn } from "@/src/lib/utils";
+import type { NotificationDTO } from "../../actions/notification-actions";
+import NotificationTypeIcon from "./NotificationTypeIcon";
+
+interface NotificationItemProps {
+  notification: NotificationDTO;
+  onSelect: (notification: NotificationDTO) => void;
+}
+
+const NotificationItem = ({ notification, onSelect }: NotificationItemProps) => {
+  const isUnread = notification.readAt === null;
+  const relativeTime = formatDistanceToNow(new Date(notification.createdAt), {
+    addSuffix: true,
+    locale: de,
+  });
+
+  return (
+    <button
+      type="button"
+      onClick={() => onSelect(notification)}
+      className={cn(
+        "flex w-full gap-3 px-4 py-3 text-left transition-colors hover:bg-accent focus-visible:bg-accent focus-visible:outline-none",
+        isUnread && "bg-accent/40"
+      )}
+    >
+      <span
+        className={cn(
+          "mt-0.5 flex size-8 shrink-0 items-center justify-center rounded-full",
+          isUnread ? "bg-primary/10 text-primary" : "bg-muted text-muted-foreground"
+        )}
+      >
+        <NotificationTypeIcon type={notification.type} className="size-4" />
+      </span>
+
+      <span className="min-w-0 flex-1">
+        <span className="flex items-start justify-between gap-2">
+          <span
+            className={cn(
+              "truncate text-sm",
+              isUnread ? "font-semibold text-foreground" : "font-medium text-foreground/90"
+            )}
+          >
+            {notification.title}
+          </span>
+          {isUnread && (
+            <span className="mt-1.5 size-2 shrink-0 rounded-full bg-primary" aria-hidden />
+          )}
+        </span>
+        <span className="mt-0.5 line-clamp-2 block text-sm text-muted-foreground">
+          {notification.body}
+        </span>
+        <span className="mt-1 block text-xs text-muted-foreground/70">{relativeTime}</span>
+      </span>
+    </button>
+  );
+};
+
+export default NotificationItem;

src/modules/notifications/ui/components/NotificationTypeIcon.tsx

@@ -0,0 +1,38 @@
+import {
+  Ban,
+  Bell,
+  BellRing,
+  CalendarPlus,
+  CalendarX,
+  Users,
+  type LucideProps,
+} from "lucide-react";
+import { NOTIFICATION_TYPES, type NotificationType } from "../../lib/notification-types";
+
+/**
+ * Rendert das zu einem Benachrichtigungstyp gehörende lucide-Icon.
+ *
+ * Bewusst als eigene, modul-scoped Komponente statt `const Icon = lookup(type)`
+ * im Aufrufer: Letzteres wertet der React-Compiler-Linter als "Komponente
+ * während Render erzeugt". Hier sind alle Icon-Referenzen statisch.
+ */
+const ICONS = {
+  Ban,
+  Bell,
+  BellRing,
+  CalendarPlus,
+  CalendarX,
+  Users,
+} as const;
+
+interface NotificationTypeIconProps extends LucideProps {
+  type: NotificationType;
+}
+
+const NotificationTypeIcon = ({ type, ...props }: NotificationTypeIconProps) => {
+  const name = NOTIFICATION_TYPES[type]?.icon as keyof typeof ICONS | undefined;
+  const Icon = (name && ICONS[name]) || Bell;
+  return <Icon {...props} />;
+};
+
+export default NotificationTypeIcon;

src/modules/settings/actions/notification-settings-actions.ts

@@ -0,0 +1,95 @@
+"use server";
+
+import { z } from "zod";
+import { prisma } from "@/src/lib/prisma";
+import { requireManager } from "@/src/lib/auth/getUser";
+import { revalidatePath } from "next/cache";
+import {
+  NOTIFICATION_TYPE_KEYS,
+  resolveNotificationSettings,
+  type NotificationType,
+} from "@/src/modules/notifications/lib/notification-types";
+
+export type NotificationSettings = Record<NotificationType, boolean>;
+
+// Alle Registry-Keys optional, jeweils boolean. Unbekannte Keys werden von
+// Zod verworfen (strict), damit nur gültige Typen gespeichert werden.
+const notificationSettingsSchema = z
+  .object(
+    Object.fromEntries(NOTIFICATION_TYPE_KEYS.map((k) => [k, z.boolean().optional()])) as Record<
+      NotificationType,
+      z.ZodOptional<z.ZodBoolean>
+    >
+  )
+  .strict();
+
+export async function getNotificationSettings(
+  businessId: string
+): Promise<{ success: true; settings: NotificationSettings } | { success: false; error: string }> {
+  const manager = await requireManager();
+
+  try {
+    const business = await prisma.business.findUnique({
+      where: { id: businessId },
+      select: { managerId: true, notificationSettings: true },
+    });
+    if (!business || business.managerId !== manager.id) {
+      return { success: false, error: "Keine Berechtigung für dieses Business." };
+    }
+
+    return {
+      success: true,
+      settings: resolveNotificationSettings(business.notificationSettings),
+    };
+  } catch (error) {
+    console.error("getNotificationSettings fehlgeschlagen:", error);
+    return {
+      success: false,
+      error: "Benachrichtigungseinstellungen konnten nicht geladen werden.",
+    };
+  }
+}
+
+export async function saveNotificationSettings(
+  businessId: string,
+  partial: Partial<NotificationSettings>
+): Promise<{ success: true } | { success: false; error: string }> {
+  const manager = await requireManager();
+
+  try {
+    const parsed = notificationSettingsSchema.safeParse(partial);
+    if (!parsed.success) {
+      return { success: false, error: "Ungültige Benachrichtigungseinstellungen." };
+    }
+
+    const business = await prisma.business.findUnique({
+      where: { id: businessId },
+      select: { managerId: true, notificationSettings: true },
+    });
+    if (!business || business.managerId !== manager.id) {
+      return { success: false, error: "Keine Berechtigung für dieses Business." };
+    }
+
+    // Auf die vollständige, aufgelöste Map mergen und komplett persistieren -
+    // so ist der gespeicherte Wert immer selbsterklärend und unabhängig von
+    // späteren Default-Änderungen in der Registry.
+    const merged: NotificationSettings = {
+      ...resolveNotificationSettings(business.notificationSettings),
+      ...parsed.data,
+    };
+
+    await prisma.business.update({
+      where: { id: businessId },
+      data: { notificationSettings: merged },
+    });
+
+    revalidatePath("/settings/notifications");
+    return { success: true };
+  } catch (error) {
+    console.error("saveNotificationSettings fehlgeschlagen:", error);
+    return {
+      success: false,
+      error: "Benachrichtigungseinstellungen konnten nicht gespeichert werden.",
+    };
+  }
+}

src/modules/settings/ui/views/settings-notification-page-view.tsx

@@ -1,5 +1,133 @@
-const SettingsNotificationPageView = () => {
+"use client";
-  return <div>SettingsNotificationPageView</div>;
+
+import { useState, useTransition } from "react";
+import { Bell } from "lucide-react";
+import { toast } from "sonner";
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue,
+} from "@/src/components/ui/select";
+import { Switch } from "@/src/components/ui/switch";
+import { cn } from "@/src/lib/utils";
+import {
+  NOTIFICATION_TYPES,
+  NOTIFICATION_TYPE_KEYS,
+  type NotificationType,
+} from "@/src/modules/notifications/lib/notification-types";
+import NotificationTypeIcon from "@/src/modules/notifications/ui/components/NotificationTypeIcon";
+import {
+  getNotificationSettings,
+  saveNotificationSettings,
+  type NotificationSettings,
+} from "../../actions/notification-settings-actions";
+
+interface SettingsNotificationPageViewProps {
+  businesses: { id: string; name: string }[];
+  initialSettings: NotificationSettings;
+}
+
+const SettingsNotificationPageView = ({
+  businesses,
+  initialSettings,
+}: SettingsNotificationPageViewProps) => {
+  const [selectedBusinessId, setSelectedBusinessId] = useState(businesses[0]?.id ?? "");
+  const [settings, setSettings] = useState<NotificationSettings>(initialSettings);
+  const [loading, startLoading] = useTransition();
+  const [, startSaving] = useTransition();
+
+  const handleBusinessChange = (businessId: string) => {
+    const previous = selectedBusinessId;
+    setSelectedBusinessId(businessId);
+    startLoading(async () => {
+      const result = await getNotificationSettings(businessId);
+      if (result.success) {
+        setSettings(result.settings);
+      } else {
+        setSelectedBusinessId(previous);
+        toast.error(result.error);
+      }
+    });
+  };
+
+  const handleToggle = (type: NotificationType, next: boolean) => {
+    const previous = settings[type];
+    setSettings((s) => ({ ...s, [type]: next }));
+    startSaving(async () => {
+      const result = await saveNotificationSettings(selectedBusinessId, { [type]: next });
+      if (!result.success) {
+        setSettings((s) => ({ ...s, [type]: previous }));
+        toast.error(result.error);
+      }
+    });
+  };
+
+  return (
+    <div className="space-y-6">
+      <div>
+        <h1 className="text-2xl flex items-center gap-2 font-bold">
+          <Bell /> Benachrichtigungen
+        </h1>
+        <p className="text-sm text-gray-500 mt-1">
+          Wähle, worüber du im Dashboard benachrichtigt werden möchtest.
+        </p>
+      </div>
+
+      {businesses.length === 0 ? (
+        <div className="border border-white/60 bg-white/55 backdrop-blur-xl rounded-xl p-6 text-center">
+          <p className="text-sm text-gray-500">Du hast noch keine Businesses angelegt.</p>
+        </div>
+      ) : (
+        <div className="space-y-4">
+          {businesses.length > 1 && (
+            <Select value={selectedBusinessId} onValueChange={handleBusinessChange}>
+              <SelectTrigger className="bg-white/60 backdrop-blur-xl border-white/40 w-full sm:w-64">
+                <SelectValue placeholder="Business" />
+              </SelectTrigger>
+              <SelectContent>
+                {businesses.map((b) => (
+                  <SelectItem key={b.id} value={b.id}>
+                    {b.name}
+                  </SelectItem>
+                ))}
+              </SelectContent>
+            </Select>
+          )}
+
+          <ul
+            className={cn(
+              "divide-y divide-white/50 rounded-xl border border-white/60 bg-white/55 backdrop-blur-xl",
+              loading && "opacity-60 transition-opacity"
+            )}
+          >
+            {NOTIFICATION_TYPE_KEYS.map((type) => {
+              const def = NOTIFICATION_TYPES[type];
+              return (
+                <li key={type} className="flex items-start gap-4 p-4">
+                  <span className="mt-0.5 flex size-9 shrink-0 items-center justify-center rounded-full bg-primary/10 text-primary">
+                    <NotificationTypeIcon type={type} className="size-4" />
+                  </span>
+                  <div className="min-w-0 flex-1">
+                    <p className="text-sm font-medium">{def.label}</p>
+                    <p className="mt-0.5 text-sm text-gray-500">{def.description}</p>
+                  </div>
+                  <Switch
+                    checked={settings[type]}
+                    onCheckedChange={(next) => handleToggle(type, next)}
+                    disabled={loading}
+                    aria-label={def.label}
+                    className="mt-1"
+                  />
+                </li>
+              );
+            })}
+          </ul>
+        </div>
+      )}
+    </div>
+  );
 };
 
 export default SettingsNotificationPageView;

tests/notifications/create-notification.test.ts

@@ -0,0 +1,125 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+
+vi.mock("@/src/lib/prisma", () => ({
+  prisma: {
+    business: { findUnique: vi.fn() },
+    notification: { create: vi.fn() },
+  },
+}));
+
+import { prisma } from "@/src/lib/prisma";
+import {
+  createNotification,
+  isNotificationEnabled,
+  notifyBusinessManager,
+} from "@/src/modules/notifications/lib/create-notification";
+
+const businessFindUnique = vi.mocked(prisma.business.findUnique);
+const notificationCreate = vi.mocked(prisma.notification.create);
+
+beforeEach(() => {
+  vi.clearAllMocks();
+});
+
+describe("createNotification", () => {
+  it("schreibt einen Datensatz und gibt true zurück", async () => {
+    notificationCreate.mockResolvedValueOnce({} as never);
+    const ok = await createNotification({
+      recipientId: "mgr-1",
+      type: "booking.created",
+      title: "Neue Buchung",
+      body: "…",
+      linkUrl: "/courses/edit/c1",
+    });
+    expect(ok).toBe(true);
+    expect(notificationCreate).toHaveBeenCalledWith({
+      data: {
+        recipientId: "mgr-1",
+        type: "booking.created",
+        title: "Neue Buchung",
+        body: "…",
+        linkUrl: "/courses/edit/c1",
+      },
+    });
+  });
+
+  it("wirft nie, sondern gibt bei DB-Fehler false zurück", async () => {
+    notificationCreate.mockRejectedValueOnce(new Error("db down"));
+    const ok = await createNotification({
+      recipientId: "mgr-1",
+      type: "booking.created",
+      title: "x",
+      body: "y",
+    });
+    expect(ok).toBe(false);
+  });
+
+  it("setzt linkUrl auf null wenn nicht angegeben", async () => {
+    notificationCreate.mockResolvedValueOnce({} as never);
+    await createNotification({ recipientId: "m", type: "course.full", title: "a", body: "b" });
+    expect(notificationCreate.mock.calls[0][0].data.linkUrl).toBeNull();
+  });
+});
+
+describe("isNotificationEnabled", () => {
+  it("gibt den Registry-Default zurück wenn kein Business gefunden wird", async () => {
+    businessFindUnique.mockResolvedValueOnce(null);
+    expect(await isNotificationEnabled("nope", "booking.created")).toBe(true);
+  });
+
+  it("respektiert ein gespeichertes Opt-out", async () => {
+    businessFindUnique.mockResolvedValueOnce({
+      notificationSettings: { "booking.created": false },
+    } as never);
+    expect(await isNotificationEnabled("b1", "booking.created")).toBe(false);
+  });
+
+  it("fällt bei DB-Fehler auf den Default zurück (Zustellung im Zweifel)", async () => {
+    businessFindUnique.mockRejectedValueOnce(new Error("boom"));
+    expect(await isNotificationEnabled("b1", "waitlist.spot")).toBe(true);
+  });
+});
+
+describe("notifyBusinessManager", () => {
+  it("no-op bei fehlender businessId", async () => {
+    await notifyBusinessManager(null, { type: "booking.created", title: "a", body: "b" });
+    await notifyBusinessManager(undefined, { type: "booking.created", title: "a", body: "b" });
+    expect(businessFindUnique).not.toHaveBeenCalled();
+    expect(notificationCreate).not.toHaveBeenCalled();
+  });
+
+  it("erstellt eine Notification für den Manager des Business", async () => {
+    businessFindUnique.mockResolvedValueOnce({
+      managerId: "mgr-42",
+      notificationSettings: null,
+    } as never);
+    notificationCreate.mockResolvedValueOnce({} as never);
+
+    await notifyBusinessManager("b1", {
+      type: "booking.created",
+      title: "Neue Buchung",
+      body: "…",
+      linkUrl: "/x",
+    });
+
+    expect(notificationCreate).toHaveBeenCalledTimes(1);
+    expect(notificationCreate.mock.calls[0][0].data.recipientId).toBe("mgr-42");
+  });
+
+  it("stellt nichts zu, wenn der Typ für das Business abgeschaltet ist", async () => {
+    businessFindUnique.mockResolvedValueOnce({
+      managerId: "mgr-42",
+      notificationSettings: { "booking.created": false },
+    } as never);
+
+    await notifyBusinessManager("b1", { type: "booking.created", title: "a", body: "b" });
+    expect(notificationCreate).not.toHaveBeenCalled();
+  });
+
+  it("wirft nie, auch wenn der Business-Lookup fehlschlägt", async () => {
+    businessFindUnique.mockRejectedValueOnce(new Error("boom"));
+    await expect(
+      notifyBusinessManager("b1", { type: "course.full", title: "a", body: "b" })
+    ).resolves.toBeUndefined();
+  });
+});

tests/notifications/notification-actions.test.ts

@@ -0,0 +1,109 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+
+vi.mock("@/src/lib/prisma", () => ({
+  prisma: {
+    notification: {
+      findMany: vi.fn(),
+      count: vi.fn(),
+      updateMany: vi.fn(),
+    },
+  },
+}));
+
+vi.mock("@/src/lib/auth/getUser", () => ({
+  requireAuthWithData: vi.fn(),
+  isManager: (u: { role: string }) => u?.role === "manager",
+  isEmployee: (u: { role: string }) => u?.role === "employee",
+}));
+
+import { prisma } from "@/src/lib/prisma";
+import { requireAuthWithData } from "@/src/lib/auth/getUser";
+import {
+  getNotifications,
+  markNotificationRead,
+  markAllNotificationsRead,
+} from "@/src/modules/notifications/actions/notification-actions";
+
+const findMany = vi.mocked(prisma.notification.findMany);
+const count = vi.mocked(prisma.notification.count);
+const updateMany = vi.mocked(prisma.notification.updateMany);
+const requireAuth = vi.mocked(requireAuthWithData);
+
+beforeEach(() => {
+  vi.clearAllMocks();
+});
+
+describe("getNotifications", () => {
+  it("liefert leeres Ergebnis für die User-Rolle", async () => {
+    requireAuth.mockResolvedValueOnce({ id: "u1", role: "user" } as never);
+    const result = await getNotifications();
+    expect(result).toEqual({ items: [], unreadCount: 0 });
+    expect(findMany).not.toHaveBeenCalled();
+  });
+
+  it("liefert leeres Ergebnis wenn keine Session besteht", async () => {
+    requireAuth.mockRejectedValueOnce(new Error("redirect"));
+    const result = await getNotifications();
+    expect(result).toEqual({ items: [], unreadCount: 0 });
+  });
+
+  it("scoped die Abfrage auf die eigene recipientId und mappt Datumsfelder", async () => {
+    requireAuth.mockResolvedValueOnce({ id: "mgr-1", role: "manager" } as never);
+    const now = new Date("2026-08-28T10:00:00Z");
+    findMany.mockResolvedValueOnce([
+      {
+        id: "n1",
+        type: "booking.created",
+        title: "T",
+        body: "B",
+        linkUrl: "/x",
+        readAt: null,
+        createdAt: now,
+      },
+    ] as never);
+    count.mockResolvedValueOnce(1);
+
+    const result = await getNotifications();
+
+    expect(findMany.mock.calls[0][0]?.where).toEqual({ recipientId: "mgr-1" });
+    expect(count.mock.calls[0][0]?.where).toEqual({ recipientId: "mgr-1", readAt: null });
+    expect(result.unreadCount).toBe(1);
+    expect(result.items[0].createdAt).toBe(now.toISOString());
+    expect(result.items[0].readAt).toBeNull();
+  });
+});
+
+describe("markNotificationRead", () => {
+  it("nimmt die recipientId in die WHERE-Bedingung auf (Ownership)", async () => {
+    requireAuth.mockResolvedValueOnce({ id: "mgr-1", role: "manager" } as never);
+    updateMany.mockResolvedValueOnce({ count: 1 } as never);
+
+    await markNotificationRead("n1");
+
+    expect(updateMany).toHaveBeenCalledWith({
+      where: { id: "n1", recipientId: "mgr-1", readAt: null },
+      data: { readAt: expect.any(Date) },
+    });
+  });
+
+  it("verweigert die User-Rolle", async () => {
+    requireAuth.mockResolvedValueOnce({ id: "u1", role: "user" } as never);
+    const result = await markNotificationRead("n1");
+    expect(result).toEqual({ success: false });
+    expect(updateMany).not.toHaveBeenCalled();
+  });
+});
+
+describe("markAllNotificationsRead", () => {
+  it("markiert nur ungelesene der eigenen recipientId", async () => {
+    requireAuth.mockResolvedValueOnce({ id: "emp-9", role: "employee" } as never);
+    updateMany.mockResolvedValueOnce({ count: 3 } as never);
+
+    await markAllNotificationsRead();
+
+    expect(updateMany).toHaveBeenCalledWith({
+      where: { recipientId: "emp-9", readAt: null },
+      data: { readAt: expect.any(Date) },
+    });
+  });
+});

tests/notifications/notification-settings-actions.test.ts

@@ -0,0 +1,88 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+
+vi.mock("@/src/lib/prisma", () => ({
+  prisma: {
+    business: { findUnique: vi.fn(), update: vi.fn() },
+  },
+}));
+
+vi.mock("@/src/lib/auth/getUser", () => ({
+  requireManager: vi.fn(),
+}));
+
+vi.mock("next/cache", () => ({
+  revalidatePath: vi.fn(),
+}));
+
+import { prisma } from "@/src/lib/prisma";
+import { requireManager } from "@/src/lib/auth/getUser";
+import {
+  getNotificationSettings,
+  saveNotificationSettings,
+} from "@/src/modules/settings/actions/notification-settings-actions";
+import { NOTIFICATION_TYPES } from "@/src/modules/notifications/lib/notification-types";
+
+const findUnique = vi.mocked(prisma.business.findUnique);
+const update = vi.mocked(prisma.business.update);
+const requireMgr = vi.mocked(requireManager);
+
+beforeEach(() => {
+  vi.clearAllMocks();
+  requireMgr.mockResolvedValue({ id: "mgr-1" } as never);
+});
+
+describe("getNotificationSettings", () => {
+  it("verweigert ein Business, das dem Manager nicht gehört", async () => {
+    findUnique.mockResolvedValueOnce({
+      managerId: "someone-else",
+      notificationSettings: null,
+    } as never);
+    const result = await getNotificationSettings("b1");
+    expect(result.success).toBe(false);
+  });
+
+  it("liefert die aufgelösten Defaults bei null", async () => {
+    findUnique.mockResolvedValueOnce({ managerId: "mgr-1", notificationSettings: null } as never);
+    const result = await getNotificationSettings("b1");
+    expect(result.success).toBe(true);
+    if (result.success) {
+      expect(result.settings["booking.created"]).toBe(
+        NOTIFICATION_TYPES["booking.created"].defaultOn
+      );
+    }
+  });
+});
+
+describe("saveNotificationSettings", () => {
+  it("lehnt unbekannte Keys ab (strict schema)", async () => {
+    const result = await saveNotificationSettings("b1", {
+      "not.a.real.type": false,
+    } as never);
+    expect(result.success).toBe(false);
+    expect(findUnique).not.toHaveBeenCalled();
+  });
+
+  it("merged partielle Änderungen auf die volle Map und persistiert sie", async () => {
+    findUnique.mockResolvedValueOnce({
+      managerId: "mgr-1",
+      notificationSettings: null,
+    } as never);
+    update.mockResolvedValueOnce({} as never);
+
+    const result = await saveNotificationSettings("b1", { "booking.created": false });
+    expect(result.success).toBe(true);
+
+    const written = update.mock.calls[0][0].data.notificationSettings as Record<string, boolean>;
+    expect(written["booking.created"]).toBe(false);
+    // alle anderen Keys sind ebenfalls enthalten (volle Map)
+    expect(Object.keys(written).sort()).toEqual(Object.keys(NOTIFICATION_TYPES).sort());
+    expect(written["course.cancelled"]).toBe(NOTIFICATION_TYPES["course.cancelled"].defaultOn);
+  });
+
+  it("verweigert ein fremdes Business auch beim Speichern", async () => {
+    findUnique.mockResolvedValueOnce({ managerId: "x", notificationSettings: null } as never);
+    const result = await saveNotificationSettings("b1", { "booking.created": true });
+    expect(result.success).toBe(false);
+    expect(update).not.toHaveBeenCalled();
+  });
+});

tests/notifications/notification-types.test.ts

@@ -0,0 +1,54 @@
+import { describe, it, expect } from "vitest";
+import {
+  NOTIFICATION_TYPES,
+  NOTIFICATION_TYPE_KEYS,
+  isNotificationType,
+  resolveNotificationSettings,
+} from "@/src/modules/notifications/lib/notification-types";
+
+describe("isNotificationType", () => {
+  it("erkennt gültige Registry-Keys", () => {
+    expect(isNotificationType("booking.created")).toBe(true);
+    expect(isNotificationType("course.cancelled")).toBe(true);
+  });
+
+  it("lehnt unbekannte Keys ab", () => {
+    expect(isNotificationType("booking.unknown")).toBe(false);
+    expect(isNotificationType("")).toBe(false);
+    expect(isNotificationType("__proto__")).toBe(false);
+  });
+});
+
+describe("resolveNotificationSettings", () => {
+  it("liefert bei null alle Registry-Defaults", () => {
+    const resolved = resolveNotificationSettings(null);
+    expect(Object.keys(resolved).sort()).toEqual([...NOTIFICATION_TYPE_KEYS].sort());
+    for (const key of NOTIFICATION_TYPE_KEYS) {
+      expect(resolved[key]).toBe(NOTIFICATION_TYPES[key].defaultOn);
+    }
+  });
+
+  it("übersteuert einzelne Keys aus dem gespeicherten Wert", () => {
+    const resolved = resolveNotificationSettings({ "booking.created": false });
+    expect(resolved["booking.created"]).toBe(false);
+    // nicht gesetzte Keys fallen weiterhin auf den Default zurück
+    expect(resolved["course.cancelled"]).toBe(NOTIFICATION_TYPES["course.cancelled"].defaultOn);
+  });
+
+  it("ignoriert unbekannte Keys und Nicht-Boolean-Werte", () => {
+    const resolved = resolveNotificationSettings({
+      "booking.created": "yes",
+      "bogus.key": true,
+      "course.full": 1,
+    });
+    expect(resolved["booking.created"]).toBe(NOTIFICATION_TYPES["booking.created"].defaultOn);
+    expect(resolved["course.full"]).toBe(NOTIFICATION_TYPES["course.full"].defaultOn);
+    expect("bogus.key" in resolved).toBe(false);
+  });
+
+  it("behandelt Arrays / primitive Werte als leer", () => {
+    expect(resolveNotificationSettings([1, 2, 3])).toEqual(resolveNotificationSettings(null));
+    expect(resolveNotificationSettings("string")).toEqual(resolveNotificationSettings(null));
+    expect(resolveNotificationSettings(42)).toEqual(resolveNotificationSettings(null));
+  });
+});