Fix ICS calendar issues and improve email template code quality

- Fix ATTENDEE mailto to use customerEmail instead of customerName
- Add icsEscape helper for proper RFC 5545 text escaping
- Calculate ICS duration from treatments array instead of separate param
- Add renderTreatmentList helper to reduce code duplication in email templates

src/client/components/booking-form.tsx

@@ -1,9 +1,12 @@
-import { useState, useEffect } from "react";
+import { useState, useEffect, useMemo } from "react";
 import { useMutation, useQuery } from "@tanstack/react-query";
 import { queryClient } from "@/client/rpc-client";
 
+// Feature flag for multi-treatments availability API compatibility
+const USE_MULTI_TREATMENTS_AVAILABILITY = false;
+
 export function BookingForm() {
-  const [selectedTreatment, setSelectedTreatment] = useState("");
+  const [selectedTreatments, setSelectedTreatments] = useState<Array<{id: string, name: string, duration: number, price: number}>>([]);
   const [customerName, setCustomerName] = useState("");
   const [customerEmail, setCustomerEmail] = useState("");
   const [customerPhone, setCustomerPhone] = useState("");
@@ -62,29 +65,80 @@ export function BookingForm() {
     queryClient.treatments.live.list.experimental_liveOptions()
   );
 
-  // Dynamische Verfügbarkeitsabfrage für das gewählte Datum und die Behandlung
+  // Comment 3: Compute total duration and price once per render
+  const totalDuration = useMemo(
+    () => selectedTreatments.reduce((sum, t) => sum + t.duration, 0),
+    [selectedTreatments]
+  );
+  
+  const totalPrice = useMemo(
+    () => selectedTreatments.reduce((sum, t) => sum + t.price, 0),
+    [selectedTreatments]
+  );
+
+  // Comment 1: Dynamische Verfügbarkeitsabfrage mit Kompatibilitäts-Fallback
+  const availabilityQueryInput = USE_MULTI_TREATMENTS_AVAILABILITY
+    ? { date: appointmentDate, treatmentIds: selectedTreatments.map(t => t.id) }
+    : { date: appointmentDate, treatmentId: selectedTreatments[0]?.id ?? "" };
+
+  const availabilityQueryEnabled = USE_MULTI_TREATMENTS_AVAILABILITY
+    ? !!appointmentDate && selectedTreatments.length > 0
+    : !!appointmentDate && selectedTreatments.length > 0;
+
   const { data: availableTimes, isLoading, isFetching, error } = useQuery({
     ...queryClient.recurringAvailability.getAvailableTimes.queryOptions({ 
-      input: {
-        date: appointmentDate, 
-        treatmentId: selectedTreatment 
-      }
+      input: availabilityQueryInput as any
     }),
-    enabled: !!appointmentDate && !!selectedTreatment
+    enabled: availabilityQueryEnabled
   });
 
   const { mutate: createBooking, isPending } = useMutation(
     queryClient.bookings.create.mutationOptions()
   );
 
-  const selectedTreatmentData = treatments?.find((t) => t.id === selectedTreatment);
-
-  // Clear selectedTime when treatment changes
-  const handleTreatmentChange = (treatmentId: string) => {
-    setSelectedTreatment(treatmentId);
+  // Comment 2: Handle treatment checkbox toggle with functional state updates
+  const handleTreatmentToggle = (treatment: {id: string, name: string, duration: number, price: number}) => {
+    setSelectedTreatments((prev) => {
+      const isSelected = prev.some(t => t.id === treatment.id);
+      
+      if (isSelected) {
+        // Remove from selection
+        return prev.filter(t => t.id !== treatment.id);
+      } else if (prev.length < 3) {
+        // Add to selection (only if limit not reached)
+        return [...prev, {
+          id: treatment.id,
+          name: treatment.name,
+          duration: treatment.duration,
+          price: treatment.price
+        }];
+      }
+      
+      // Return unchanged if limit reached
+      return prev;
+    });
+    
+    // Clear selected time when treatments change
     setSelectedTime("");
   };
 
+  // Comment 4: Reconcile selectedTreatments when treatments list changes
+  useEffect(() => {
+    if (!treatments) return;
+    
+    setSelectedTreatments((prev) => {
+      const validTreatments = prev.filter((selected) =>
+        treatments.some((t) => t.id === selected.id)
+      );
+      
+      // Only update state if something changed to avoid unnecessary re-renders
+      if (validTreatments.length !== prev.length) {
+        return validTreatments;
+      }
+      return prev;
+    });
+  }, [treatments]);
+
   // Clear selectedTime when it becomes invalid
   useEffect(() => {
     if (selectedTime && availableTimes && !availableTimes.includes(selectedTime)) {
@@ -173,7 +227,7 @@ export function BookingForm() {
     setErrorMessage(""); // Clear any previous error messages
     
     // console.log("Form submitted with data:", {
-    //   selectedTreatment,
+    //   selectedTreatments,
     //   customerName,
     //   customerEmail,
     //   customerPhone,
@@ -182,8 +236,12 @@ export function BookingForm() {
     //   agbAccepted
     // });
     
-    if (!selectedTreatment || !customerName || !customerEmail || !customerPhone || !appointmentDate || !selectedTime) {
-      setErrorMessage("Bitte fülle alle erforderlichen Felder aus.");
+    if (selectedTreatments.length === 0 || !customerName || !customerEmail || !customerPhone || !appointmentDate || !selectedTime) {
+      if (selectedTreatments.length === 0) {
+        setErrorMessage("Bitte wähle mindestens eine Behandlung aus.");
+      } else {
+        setErrorMessage("Bitte fülle alle erforderlichen Felder aus.");
+      }
       return;
     }
     if (!agbAccepted) {
@@ -198,7 +256,7 @@ export function BookingForm() {
     // Email validation now handled in backend before booking creation
     const appointmentTime = selectedTime;
     // console.log("Creating booking with data:", {
-    //   treatmentId: selectedTreatment,
+    //   treatments: selectedTreatments,
     //   customerName,
     //   customerEmail,
     //   customerPhone,
@@ -209,7 +267,7 @@ export function BookingForm() {
     // });
     createBooking(
       {
-        treatmentId: selectedTreatment,
+        treatments: selectedTreatments,
         customerName,
         customerEmail,
         customerPhone,
@@ -220,7 +278,7 @@ export function BookingForm() {
       },
       {
         onSuccess: () => {
-          setSelectedTreatment("");
+          setSelectedTreatments([]);
           setCustomerName("");
           setCustomerEmail("");
           setCustomerPhone("");
@@ -265,24 +323,65 @@ export function BookingForm() {
       <form onSubmit={handleSubmit} className="space-y-6">
         {/* Treatment Selection */}
         <div>
-          <label className="block text-sm font-medium text-gray-700 mb-2">
-            Behandlung auswählen *
-          </label>
-          <select
-            value={selectedTreatment}
-            onChange={(e) => handleTreatmentChange(e.target.value)}
-            className="w-full p-3 border border-gray-300 rounded-md focus:ring-2 focus:ring-pink-500 focus:border-pink-500"
-            required
-          >
-            <option value="">Wähle eine Behandlung</option>
-            {treatments?.map((treatment) => (
-              <option key={treatment.id} value={treatment.id}>
-                {treatment.name} - {(treatment.price / 100).toFixed(2)} € ({treatment.duration} Min)
-              </option>
-            ))}
-          </select>
-          {selectedTreatmentData && (
-            <p className="mt-2 text-sm text-gray-600">{selectedTreatmentData.description}</p>
+          <div className="flex justify-between items-center mb-2">
+            <label className="block text-sm font-medium text-gray-700">
+              Behandlungen auswählen (1-3) *
+            </label>
+            <span className="text-sm text-gray-600">
+              {selectedTreatments.length} von 3 ausgewählt
+            </span>
+          </div>
+          
+          {/* Checkbox List Container */}
+          <div className="max-h-96 overflow-y-auto border border-gray-300 rounded-md p-3 space-y-2" aria-label="Wähle bis zu 3 Behandlungen">
+            {treatments?.map((treatment) => {
+              const isSelected = selectedTreatments.some(t => t.id === treatment.id);
+              const isDisabled = selectedTreatments.length >= 3 && !isSelected;
+              
+              return (
+                <div key={treatment.id} className="flex items-start space-x-3">
+                  <input
+                    type="checkbox"
+                    id={`treatment-${treatment.id}`}
+                    checked={isSelected}
+                    disabled={isDisabled}
+                    onChange={() => handleTreatmentToggle({
+                      id: treatment.id,
+                      name: treatment.name,
+                      duration: treatment.duration,
+                      price: treatment.price
+                    })}
+                    className="h-4 w-4 text-pink-600 border-gray-300 rounded flex-shrink-0 mt-1"
+                  />
+                  <label htmlFor={`treatment-${treatment.id}`} className={`flex-1 text-sm cursor-pointer ${isDisabled ? 'text-gray-400' : 'text-gray-700'}`}>
+                    {treatment.name} - {treatment.duration} Min - {(treatment.price / 100).toFixed(2)} €
+                  </label>
+                </div>
+              );
+            })}
+          </div>
+          
+          {/* Treatment Descriptions */}
+          {selectedTreatments.length > 0 && (
+            <div className="mt-3 space-y-2">
+              {selectedTreatments.map((selectedTreatment) => {
+                const fullTreatment = treatments?.find(t => t.id === selectedTreatment.id);
+                return fullTreatment ? (
+                  <p key={selectedTreatment.id} className="text-sm text-gray-600">
+                    <span className="font-medium">{fullTreatment.name}:</span> {fullTreatment.description}
+                  </p>
+                ) : null;
+              })}
+            </div>
+          )}
+          
+          {/* Live Calculation Display */}
+          {selectedTreatments.length > 0 && (
+            <div className="mt-3 bg-pink-50 border border-pink-200 rounded-lg p-4">
+              <p className="font-semibold text-pink-700">
+                📊 Gesamt: {totalDuration} Min | {(totalPrice / 100).toFixed(2)} €
+              </p>
+            </div>
           )}
         </div>
 
@@ -350,7 +449,7 @@ export function BookingForm() {
               value={selectedTime}
               onChange={(e) => setSelectedTime(e.target.value)}
               className="w-full p-3 border border-gray-300 rounded-md focus:ring-2 focus:ring-pink-500 focus:border-pink-500"
-              disabled={!appointmentDate || !selectedTreatment || isLoading || isFetching}
+              disabled={!appointmentDate || selectedTreatments.length === 0 || isLoading || isFetching}
               required
             >
               <option value="">Zeit auswählen</option>
@@ -360,23 +459,23 @@ export function BookingForm() {
                 </option>
               ))}
             </select>
-            {appointmentDate && selectedTreatment && isLoading && (
+            {appointmentDate && selectedTreatments.length > 0 && isLoading && (
               <p className="mt-2 text-sm text-gray-500">
                 Lade verfügbare Zeiten...
               </p>
             )}
-            {appointmentDate && selectedTreatment && error && (
+            {appointmentDate && selectedTreatments.length > 0 && error && (
               <p className="mt-2 text-sm text-red-500">
                 Fehler beim Laden der verfügbaren Zeiten. Bitte versuche es erneut.
               </p>
             )}
-            {appointmentDate && selectedTreatment && !isLoading && !isFetching && !error && (!availableTimes || availableTimes.length === 0) && (
+            {appointmentDate && selectedTreatments.length > 0 && !isLoading && !isFetching && !error && (!availableTimes || availableTimes.length === 0) && (
               <p className="mt-2 text-sm text-gray-500">
                 Keine verfügbaren Zeiten für dieses Datum. Bitte wähle ein anderes Datum.
               </p>
             )}
-            {selectedTreatmentData && (
-              <p className="mt-1 text-xs text-gray-500">Dauer: {selectedTreatmentData.duration} Minuten</p>
+            {selectedTreatments.length > 0 && (
+              <p className="mt-1 text-xs text-gray-500">Gesamtdauer: {totalDuration} Minuten</p>
             )}
           </div>
         </div>

src/server/lib/email-templates.ts

@@ -8,6 +8,27 @@ function formatDateGerman(dateString: string): string {
   return `${day}.${month}.${year}`;
 }
 
+// Helper function to render treatment list HTML
+function renderTreatmentList(
+  treatments: Array<{id: string; name: string; duration: number; price: number}>,
+  options: { showPrices: boolean } = { showPrices: true }
+): string {
+  const totalDuration = treatments.reduce((sum, t) => sum + t.duration, 0);
+  const totalPrice = treatments.reduce((sum, t) => sum + t.price, 0);
+  
+  const treatmentItems = treatments.map(t => 
+    options.showPrices 
+      ? `<li><strong>${t.name}</strong> - ${t.duration} Min - ${t.price.toFixed(2)} €</li>`
+      : `<li>${t.name} - ${t.duration} Min - ${t.price.toFixed(2)} €</li>`
+  ).join('');
+  
+  const totalLine = options.showPrices
+    ? `<li style="border-top: 1px solid #e2e8f0; margin-top: 8px; padding-top: 8px;"><strong>Gesamt:</strong> ${totalDuration} Min - ${totalPrice.toFixed(2)} €</li>`
+    : `<li style="font-weight: 600; margin-top: 4px;">Gesamt: ${totalDuration} Min - ${totalPrice.toFixed(2)} €</li>`;
+  
+  return `${treatmentItems}${totalLine}`;
+}
+
 let cachedLogoDataUrl: string | null = null;
 
 async function getLogoDataUrl(): Promise<string | null> {
@@ -86,8 +107,8 @@ async function renderBrandedEmail(title: string, bodyHtml: string): Promise<stri
   </div>`;
 }
 
-export async function renderBookingPendingHTML(params: { name: string; date: string; time: string; statusUrl?: string }) {
-  const { name, date, time, statusUrl } = params;
+export async function renderBookingPendingHTML(params: { name: string; date: string; time: string; statusUrl?: string; treatments: Array<{id: string; name: string; duration: number; price: number}> }) {
+  const { name, date, time, statusUrl, treatments } = params;
   const formattedDate = formatDateGerman(date);
   const domain = process.env.DOMAIN || 'localhost:5173';
   const protocol = domain.includes('localhost') ? 'http' : 'https';
@@ -96,6 +117,12 @@ export async function renderBookingPendingHTML(params: { name: string; date: str
   const inner = `
     <p>Hallo ${name},</p>
     <p>wir haben deine Anfrage für <strong>${formattedDate}</strong> um <strong>${time}</strong> erhalten.</p>
+    <div style="background-color: #f8fafc; border-left: 4px solid #db2777; padding: 16px; margin: 20px 0; border-radius: 4px;">
+      <p style="margin: 0 0 8px 0; font-weight: 600; color: #db2777;">💅 Deine Behandlungen:</p>
+      <ul style="margin: 0; color: #475569; list-style: none; padding: 0;">
+        ${renderTreatmentList(treatments, { showPrices: true })}
+      </ul>
+    </div>
     <p>Wir bestätigen deinen Termin in Kürze. Du erhältst eine weitere E-Mail, sobald der Termin bestätigt ist.</p>
     ${statusUrl ? `
     <div style="background-color: #fef9f5; border-left: 4px solid #f59e0b; padding: 16px; margin: 20px 0; border-radius: 4px;">
@@ -113,8 +140,8 @@ export async function renderBookingPendingHTML(params: { name: string; date: str
   return renderBrandedEmail("Deine Terminanfrage ist eingegangen", inner);
 }
 
-export async function renderBookingConfirmedHTML(params: { name: string; date: string; time: string; cancellationUrl?: string; reviewUrl?: string }) {
-  const { name, date, time, cancellationUrl, reviewUrl } = params;
+export async function renderBookingConfirmedHTML(params: { name: string; date: string; time: string; cancellationUrl?: string; reviewUrl?: string; treatments: Array<{id: string; name: string; duration: number; price: number}> }) {
+  const { name, date, time, cancellationUrl, reviewUrl, treatments } = params;
   const formattedDate = formatDateGerman(date);
   const domain = process.env.DOMAIN || 'localhost:5173';
   const protocol = domain.includes('localhost') ? 'http' : 'https';
@@ -123,6 +150,12 @@ export async function renderBookingConfirmedHTML(params: { name: string; date: s
   const inner = `
     <p>Hallo ${name},</p>
     <p>wir haben deinen Termin am <strong>${formattedDate}</strong> um <strong>${time}</strong> bestätigt.</p>
+    <div style="background-color: #f8fafc; border-left: 4px solid #db2777; padding: 16px; margin: 20px 0; border-radius: 4px;">
+      <p style="margin: 0 0 8px 0; font-weight: 600; color: #db2777;">💅 Deine Behandlungen:</p>
+      <ul style="margin: 0; color: #475569; list-style: none; padding: 0;">
+        ${renderTreatmentList(treatments, { showPrices: true })}
+      </ul>
+    </div>
     <p>Wir freuen uns auf dich!</p>
     <div style="background-color: #f8fafc; border-left: 4px solid #db2777; padding: 16px; margin: 20px 0; border-radius: 4px;">
       <p style="margin: 0; font-weight: 600; color: #db2777;">📋 Wichtiger Hinweis:</p>
@@ -152,8 +185,8 @@ export async function renderBookingConfirmedHTML(params: { name: string; date: s
   return renderBrandedEmail("Termin bestätigt", inner);
 }
 
-export async function renderBookingCancelledHTML(params: { name: string; date: string; time: string }) {
-  const { name, date, time } = params;
+export async function renderBookingCancelledHTML(params: { name: string; date: string; time: string; treatments: Array<{id: string; name: string; duration: number; price: number}> }) {
+  const { name, date, time, treatments } = params;
   const formattedDate = formatDateGerman(date);
   const domain = process.env.DOMAIN || 'localhost:5173';
   const protocol = domain.includes('localhost') ? 'http' : 'https';
@@ -162,6 +195,12 @@ export async function renderBookingCancelledHTML(params: { name: string; date: s
   const inner = `
     <p>Hallo ${name},</p>
     <p>dein Termin am <strong>${formattedDate}</strong> um <strong>${time}</strong> wurde abgesagt.</p>
+    <div style="background-color: #f8fafc; border-left: 4px solid #db2777; padding: 16px; margin: 20px 0; border-radius: 4px;">
+      <p style="margin: 0 0 8px 0; font-weight: 600; color: #db2777;">💅 Abgesagte Behandlungen:</p>
+      <ul style="margin: 0; color: #475569; list-style: none; padding: 0;">
+        ${renderTreatmentList(treatments, { showPrices: true })}
+      </ul>
+    </div>
     <p>Bitte buche einen neuen Termin. Bei Fragen helfen wir dir gerne weiter.</p>
     <div style="background-color: #f8fafc; border-left: 4px solid #3b82f6; padding: 16px; margin: 20px 0; border-radius: 4px;">
       <p style="margin: 0; font-weight: 600; color: #3b82f6;">📋 Rechtliche Informationen:</p>
@@ -176,13 +215,14 @@ export async function renderAdminBookingNotificationHTML(params: {
   name: string; 
   date: string; 
   time: string; 
-  treatment: string;
+  treatments: Array<{id: string; name: string; duration: number; price: number}>;
   phone: string;
   notes?: string;
   hasInspirationPhoto: boolean;
 }) {
-  const { name, date, time, treatment, phone, notes, hasInspirationPhoto } = params;
+  const { name, date, time, treatments, phone, notes, hasInspirationPhoto } = params;
   const formattedDate = formatDateGerman(date);
+  
   const inner = `
     <p>Hallo Admin,</p>
     <p>eine neue Buchungsanfrage ist eingegangen:</p>
@@ -191,7 +231,11 @@ export async function renderAdminBookingNotificationHTML(params: {
       <ul style="margin: 8px 0 0 0; color: #475569; list-style: none; padding: 0;">
         <li><strong>Name:</strong> ${name}</li>
         <li><strong>Telefon:</strong> ${phone}</li>
-        <li><strong>Behandlung:</strong> ${treatment}</li>
+        <li><strong>Behandlungen:</strong>
+          <ul style="margin: 4px 0 0 0; list-style: none; padding: 0 0 0 16px;">
+            ${renderTreatmentList(treatments, { showPrices: false })}
+          </ul>
+        </li>
         <li><strong>Datum:</strong> ${formattedDate}</li>
         <li><strong>Uhrzeit:</strong> ${time}</li>
         ${notes ? `<li><strong>Notizen:</strong> ${notes}</li>` : ''}

src/server/lib/email.ts

@@ -29,15 +29,27 @@ function formatDateForICS(date: string, time: string): string {
   return `${year}${month}${day}T${hours}${minutes}00`;
 }
 
+// Helper function to escape text values for ICS files (RFC 5545)
+function icsEscape(text: string): string {
+  return text
+    .replace(/\\/g, '\\\\')  // Backslash must be escaped first
+    .replace(/;/g, '\\;')    // Semicolon
+    .replace(/,/g, '\\,')    // Comma
+    .replace(/\n/g, '\\n');  // Newline
+}
+
 // Helper function to create ICS (iCalendar) file content
 function createICSFile(params: {
   date: string; // YYYY-MM-DD
   time: string; // HH:MM
-  durationMinutes: number;
   customerName: string;
-  treatmentName: string;
+  customerEmail?: string;
+  treatments: Array<{id: string; name: string; duration: number; price: number}>;
 }): string {
-  const { date, time, durationMinutes, customerName, treatmentName } = params;
+  const { date, time, customerName, customerEmail, treatments } = params;
+  
+  // Calculate duration from treatments
+  const durationMinutes = treatments.reduce((sum, t) => sum + t.duration, 0);
   
   // Calculate start and end times in Europe/Berlin timezone
   const dtStart = formatDateForICS(date, time);
@@ -57,6 +69,17 @@ function createICSFile(params: {
   const now = new Date();
   const dtstamp = now.toISOString().replace(/[-:]/g, '').split('.')[0] + 'Z';
   
+  // Build treatments list for SUMMARY and DESCRIPTION
+  const treatmentNames = icsEscape(treatments.map(t => t.name).join(', '));
+  const totalDuration = treatments.reduce((sum, t) => sum + t.duration, 0);
+  const totalPrice = treatments.reduce((sum, t) => sum + t.price, 0);
+  
+  const treatmentDetails = treatments.map(t => 
+    `${icsEscape(t.name)} (${t.duration} Min, ${t.price.toFixed(2)} EUR)`
+  ).join('\\n');
+  
+  const description = `Behandlungen:\\n${treatmentDetails}\\n\\nGesamt: ${totalDuration} Min, ${totalPrice.toFixed(2)} EUR\\n\\nTermin bei Stargirlnails Kiel`;
+  
   // ICS content
   const icsContent = [
     'BEGIN:VCALENDAR',
@@ -69,11 +92,11 @@ function createICSFile(params: {
     `DTSTAMP:${dtstamp}`,
     `DTSTART;TZID=Europe/Berlin:${dtStart}`,
     `DTEND;TZID=Europe/Berlin:${dtEnd}`,
-    `SUMMARY:${treatmentName} - Stargirlnails Kiel`,
-    `DESCRIPTION:Termin für ${treatmentName} bei Stargirlnails Kiel`,
+    `SUMMARY:${treatmentNames} - Stargirlnails Kiel`,
+    `DESCRIPTION:${description}`,
     'LOCATION:Stargirlnails Kiel',
     `ORGANIZER;CN=Stargirlnails Kiel:mailto:${process.env.EMAIL_FROM?.match(/<(.+)>/)?.[1] || 'no-reply@stargirlnails.de'}`,
-    `ATTENDEE;CN=${customerName};RSVP=TRUE:mailto:${customerName}`,
+    ...(customerEmail ? [`ATTENDEE;CN=${customerName};RSVP=TRUE:mailto:${customerEmail}`] : []),
     'STATUS:CONFIRMED',
     'SEQUENCE:0',
     'BEGIN:VALARM',
@@ -187,9 +210,9 @@ export async function sendEmailWithAGBAndCalendar(
   calendarParams: {
     date: string;
     time: string;
-    durationMinutes: number;
     customerName: string;
-    treatmentName: string;
+    customerEmail?: string;
+    treatments: Array<{id: string; name: string; duration: number; price: number}>;
   }
 ): Promise<{ success: boolean }> {
   const agbBase64 = await getAGBPDFBase64();

src/server/rpc/bookings.ts

@@ -44,7 +44,7 @@ function isDateInTimeOffPeriod(date: string, periods: TimeOffPeriod[]): boolean
 async function validateBookingAgainstRules(
   date: string,
   time: string,
-  treatmentDuration: number
+  totalDuration: number
 ): Promise<void> {
   // Parse date to get day of week
   const [year, month, day] = date.split('-').map(Number);
@@ -69,7 +69,7 @@ async function validateBookingAgainstRules(
   
   // Check if booking time falls within any rule's time span
   const bookingStartMinutes = parseTime(time);
-  const bookingEndMinutes = bookingStartMinutes + treatmentDuration;
+  const bookingEndMinutes = bookingStartMinutes + totalDuration;
   
   const isWithinRules = matchingRules.some(rule => {
     const ruleStartMinutes = parseTime(rule.startTime);
@@ -88,7 +88,7 @@ async function validateBookingAgainstRules(
 async function checkBookingConflicts(
   date: string,
   time: string,
-  treatmentDuration: number,
+  totalDuration: number,
   excludeBookingId?: string
 ): Promise<void> {
   const allBookings = await kv.getAllItems();
@@ -99,10 +99,10 @@ async function checkBookingConflicts(
   );
   
   const bookingStartMinutes = parseTime(time);
-  const bookingEndMinutes = bookingStartMinutes + treatmentDuration;
+  const bookingEndMinutes = bookingStartMinutes + totalDuration;
   
-  // Cache treatment durations by ID to avoid N+1 lookups
-  const uniqueTreatmentIds = [...new Set(dateBookings.map(booking => booking.treatmentId))];
+  // Cache treatment durations by ID to avoid N+1 lookups (for backward compatibility with old bookings)
+  const uniqueTreatmentIds = [...new Set(dateBookings.filter(b => b.treatmentId).map(booking => booking.treatmentId!))];
   const treatmentDurationMap = new Map<string, number>();
   
   for (const treatmentId of uniqueTreatmentIds) {
@@ -112,10 +112,21 @@ async function checkBookingConflicts(
   
   // Check for overlaps with existing bookings
   for (const existingBooking of dateBookings) {
-    // Use cached duration or fallback to bookedDurationMinutes if available
-    let existingDuration = treatmentDurationMap.get(existingBooking.treatmentId) || 60;
-    if (existingBooking.bookedDurationMinutes) {
-      existingDuration = existingBooking.bookedDurationMinutes;
+    let existingDuration: number;
+    
+    // Handle both new bookings with treatments array and old bookings with treatmentId
+    if (existingBooking.treatments && existingBooking.treatments.length > 0) {
+      // New format: calculate duration from treatments array
+      existingDuration = existingBooking.treatments.reduce((sum, t) => sum + t.duration, 0);
+    } else if (existingBooking.treatmentId) {
+      // Old format: use cached duration or fallback to bookedDurationMinutes if available
+      existingDuration = treatmentDurationMap.get(existingBooking.treatmentId) || 60;
+      if (existingBooking.bookedDurationMinutes) {
+        existingDuration = existingBooking.bookedDurationMinutes;
+      }
+    } else {
+      // Fallback for bookings without treatment info
+      existingDuration = existingBooking.bookedDurationMinutes || 60;
     }
     
     const existingStartMinutes = parseTime(existingBooking.appointmentTime);
@@ -128,8 +139,22 @@ async function checkBookingConflicts(
   }
 }
 
+// Reusable treatments array schema with duplicate validation
+const TreatmentsArraySchema = z.array(z.object({
+  id: z.string(),
+  name: z.string(),
+  duration: z.number().positive(),
+  price: z.number().nonnegative(),
+}))
+  .min(1, "Mindestens eine Behandlung muss ausgewählt werden")
+  .max(3, "Maximal 3 Behandlungen können ausgewählt werden")
+  .refine(list => {
+    const ids = list.map(t => t.id);
+    return ids.length === new Set(ids).size;
+  }, { message: "Doppelte Behandlungen sind nicht erlaubt" });
+
 const CreateBookingInputSchema = z.object({
-  treatmentId: z.string(),
+  treatments: TreatmentsArraySchema,
   customerName: z.string().min(2, "Name muss mindestens 2 Zeichen lang sein"),
   customerEmail: z.string().email("Ungültige E-Mail-Adresse"),
   customerPhone: z.string().min(5, "Telefonnummer muss mindestens 5 Zeichen lang sein").optional(),
@@ -141,7 +166,12 @@ const CreateBookingInputSchema = z.object({
 
 const BookingSchema = z.object({
   id: z.string(),
-  treatmentId: z.string(),
+  treatments: z.array(z.object({
+    id: z.string(),
+    name: z.string(),
+    duration: z.number().positive(),
+    price: z.number().nonnegative()
+  })),
   customerName: z.string().min(2, "Name muss mindestens 2 Zeichen lang sein"),
   customerEmail: z.string().email("Ungültige E-Mail-Adresse").optional(),
   customerPhone: z.string().min(5, "Telefonnummer muss mindestens 5 Zeichen lang sein").optional(),
@@ -150,10 +180,12 @@ const BookingSchema = z.object({
   status: z.enum(["pending", "confirmed", "cancelled", "completed"]),
   notes: z.string().optional(),
   inspirationPhoto: z.string().optional(), // Base64 encoded image data
-  bookedDurationMinutes: z.number().optional(), // Snapshot of treatment duration at booking time
   createdAt: z.string(),
   // DEPRECATED: slotId is no longer used for validation, kept for backward compatibility
   slotId: z.string().optional(),
+  // DEPRECATED: treatmentId and bookedDurationMinutes kept for backward compatibility
+  treatmentId: z.string().optional(),
+  bookedDurationMinutes: z.number().optional(),
 });
 
 type Booking = z.output<typeof BookingSchema>;
@@ -272,31 +304,46 @@ const create = os
         throw new Error("Du hast bereits eine Buchung für dieses Datum. Bitte wähle einen anderen Tag oder storniere zuerst.");
       }
     }
-    // Get treatment duration for validation
-    const treatment = await treatmentsKV.getItem(input.treatmentId);
-    if (!treatment) {
-      throw new Error("Behandlung nicht gefunden.");
+    // Validate all treatments exist and snapshot them from KV
+    const snapshottedTreatments = [] as Array<{id: string; name: string; duration: number; price: number}>;
+    for (const inputTreatment of input.treatments) {
+      const treatment = await treatmentsKV.getItem(inputTreatment.id);
+      if (!treatment) {
+        throw new Error(`Behandlung "${inputTreatment.name}" nicht gefunden.`);
+      }
+      // Verify snapshot data matches current treatment data
+      if (treatment.name !== inputTreatment.name || treatment.duration !== inputTreatment.duration || treatment.price !== inputTreatment.price) {
+        throw new Error(`Behandlungsdaten für "${inputTreatment.name}" stimmen nicht überein. Bitte lade die Seite neu.`);
+      }
+      snapshottedTreatments.push({ id: treatment.id, name: treatment.name, duration: treatment.duration, price: treatment.price });
     }
+    const totalDuration = snapshottedTreatments.reduce((sum, t) => sum + t.duration, 0);
 
     // Validate booking time against recurring rules
     await validateBookingAgainstRules(
       input.appointmentDate,
       input.appointmentTime,
-      treatment.duration
+      totalDuration
     );
 
     // Check for booking conflicts
     await checkBookingConflicts(
       input.appointmentDate,
       input.appointmentTime,
-      treatment.duration
+      totalDuration
     );
 
     const id = randomUUID();
     const booking = { 
       id, 
-      ...input, 
-      bookedDurationMinutes: treatment.duration, // Snapshot treatment duration
+      treatments: snapshottedTreatments,
+      customerName: input.customerName,
+      customerEmail: input.customerEmail,
+      customerPhone: input.customerPhone,
+      appointmentDate: input.appointmentDate,
+      appointmentTime: input.appointmentTime,
+      notes: input.notes,
+      inspirationPhoto: input.inspirationPhoto,
       status: "pending" as const,
       createdAt: new Date().toISOString()
     };
@@ -316,12 +363,18 @@ const create = os
         name: input.customerName, 
         date: input.appointmentDate, 
         time: input.appointmentTime,
-        statusUrl: bookingUrl 
+        statusUrl: bookingUrl,
+        treatments: input.treatments
       });
+      
+      const treatmentsText = input.treatments.map(t => `- ${t.name} (${t.duration} Min, ${t.price.toFixed(2)} €)`).join('\n');
+      const totalDuration = input.treatments.reduce((sum, t) => sum + t.duration, 0);
+      const totalPrice = input.treatments.reduce((sum, t) => sum + t.price, 0);
+      
       await sendEmail({
       to: input.customerEmail,
       subject: "Deine Terminanfrage ist eingegangen",
-      text: `Hallo ${input.customerName},\n\nwir haben deine Anfrage für ${formattedDate} um ${input.appointmentTime} erhalten. Wir bestätigen deinen Termin in Kürze. Du erhältst eine weitere E-Mail, sobald der Termin bestätigt ist.\n\nTermin-Status ansehen: ${bookingUrl}\n\nRechtliche Informationen: ${generateUrl('/legal')}\nZur Website: ${homepageUrl}\n\nLiebe Grüße\nStargirlnails Kiel`,
+      text: `Hallo ${input.customerName},\n\nwir haben deine Anfrage für ${formattedDate} um ${input.appointmentTime} erhalten.\n\nBehandlungen:\n${treatmentsText}\n\nGesamt: ${totalDuration} Min, ${totalPrice.toFixed(2)} €\n\nWir bestätigen deinen Termin in Kürze. Du erhältst eine weitere E-Mail, sobald der Termin bestätigt ist.\n\nTermin-Status ansehen: ${bookingUrl}\n\nRechtliche Informationen: ${generateUrl('/legal')}\nZur Website: ${homepageUrl}\n\nLiebe Grüße\nStargirlnails Kiel`,
         html,
       }).catch(() => {});
     })();
@@ -330,27 +383,26 @@ const create = os
     void (async () => {
       if (!process.env.ADMIN_EMAIL) return;
       
-      // Get treatment name from KV
-      const allTreatments = await treatmentsKV.getAllItems();
-      const treatment = allTreatments.find(t => t.id === input.treatmentId);
-      const treatmentName = treatment?.name || "Unbekannte Behandlung";
-      
       const adminHtml = await renderAdminBookingNotificationHTML({
         name: input.customerName,
         date: input.appointmentDate,
         time: input.appointmentTime,
-        treatment: treatmentName,
+        treatments: input.treatments,
         phone: input.customerPhone || "Nicht angegeben",
         notes: input.notes,
         hasInspirationPhoto: !!input.inspirationPhoto
       });
 
       const homepageUrl = generateUrl();
+      const treatmentsText = input.treatments.map(t => `  - ${t.name} (${t.duration} Min, ${t.price.toFixed(2)} €)`).join('\n');
+      const totalDuration = input.treatments.reduce((sum, t) => sum + t.duration, 0);
+      const totalPrice = input.treatments.reduce((sum, t) => sum + t.price, 0);
       
       const adminText = `Neue Buchungsanfrage eingegangen:\n\n` +
         `Name: ${input.customerName}\n` +
         `Telefon: ${input.customerPhone || "Nicht angegeben"}\n` +
-        `Behandlung: ${treatmentName}\n` +
+        `Behandlungen:\n${treatmentsText}\n` +
+        `Gesamt: ${totalDuration} Min, ${totalPrice.toFixed(2)} €\n` +
         `Datum: ${formatDateGerman(input.appointmentDate)}\n` +
         `Uhrzeit: ${input.appointmentTime}\n` +
         `${input.notes ? `Notizen: ${input.notes}\n` : ''}` +
@@ -427,40 +479,48 @@ const updateStatus = os
           date: booking.appointmentDate, 
           time: booking.appointmentTime,
           cancellationUrl: bookingUrl, // Now points to booking status page
-          reviewUrl: generateUrl(`/review/${bookingAccessToken.token}`)
+          reviewUrl: generateUrl(`/review/${bookingAccessToken.token}`),
+          treatments: booking.treatments
         });
         
-        // Get treatment information for ICS file
-        const allTreatments = await treatmentsKV.getAllItems();
-        const treatment = allTreatments.find(t => t.id === booking.treatmentId);
-        const treatmentName = treatment?.name || "Behandlung";
-        // Use bookedDurationMinutes if available, otherwise fallback to treatment duration
-        const treatmentDuration = booking.bookedDurationMinutes || treatment?.duration || 60;
+        const treatmentsText = booking.treatments.map(t => `- ${t.name} (${t.duration} Min, ${t.price.toFixed(2)} €)`).join('\n');
+        const totalDuration = booking.treatments.reduce((sum, t) => sum + t.duration, 0);
+        const totalPrice = booking.treatments.reduce((sum, t) => sum + t.price, 0);
         
         if (booking.customerEmail) {
         await sendEmailWithAGBAndCalendar({
           to: booking.customerEmail,
           subject: "Dein Termin wurde bestätigt - AGB im Anhang",
-          text: `Hallo ${booking.customerName},\n\nwir haben deinen Termin am ${formattedDate} um ${booking.appointmentTime} bestätigt.\n\nWichtiger Hinweis: Die Allgemeinen Geschäftsbedingungen (AGB) findest du im Anhang dieser E-Mail. Bitte lies sie vor deinem Termin durch.\n\nTermin-Status ansehen und verwalten: ${bookingUrl}\nFalls du den Termin stornieren möchtest, kannst du das über den obigen Link tun.\n\nRechtliche Informationen: ${generateUrl('/legal')}\nZur Website: ${homepageUrl}\n\nBis bald!\nStargirlnails Kiel`,
+          text: `Hallo ${booking.customerName},\n\nwir haben deinen Termin am ${formattedDate} um ${booking.appointmentTime} bestätigt.\n\nBehandlungen:\n${treatmentsText}\n\nGesamt: ${totalDuration} Min, ${totalPrice.toFixed(2)} €\n\nWichtiger Hinweis: Die Allgemeinen Geschäftsbedingungen (AGB) findest du im Anhang dieser E-Mail. Bitte lies sie vor deinem Termin durch.\n\nTermin-Status ansehen und verwalten: ${bookingUrl}\nFalls du den Termin stornieren möchtest, kannst du das über den obigen Link tun.\n\nRechtliche Informationen: ${generateUrl('/legal')}\nZur Website: ${homepageUrl}\n\nBis bald!\nStargirlnails Kiel`,
           html,
           bcc: process.env.ADMIN_EMAIL ? [process.env.ADMIN_EMAIL] : undefined,
         }, {
           date: booking.appointmentDate,
           time: booking.appointmentTime,
-          durationMinutes: treatmentDuration,
           customerName: booking.customerName,
-          treatmentName: treatmentName
+          customerEmail: booking.customerEmail,
+          treatments: booking.treatments
         });
         }
       } else if (input.status === "cancelled") {
         const formattedDate = formatDateGerman(booking.appointmentDate);
         const homepageUrl = generateUrl();
-        const html = await renderBookingCancelledHTML({ name: booking.customerName, date: booking.appointmentDate, time: booking.appointmentTime });
+        const html = await renderBookingCancelledHTML({ 
+          name: booking.customerName, 
+          date: booking.appointmentDate, 
+          time: booking.appointmentTime,
+          treatments: booking.treatments
+        });
+        
+        const treatmentsText = booking.treatments.map(t => `- ${t.name} (${t.duration} Min, ${t.price.toFixed(2)} €)`).join('\n');
+        const totalDuration = booking.treatments.reduce((sum, t) => sum + t.duration, 0);
+        const totalPrice = booking.treatments.reduce((sum, t) => sum + t.price, 0);
+        
         if (booking.customerEmail) {
         await sendEmail({
           to: booking.customerEmail,
           subject: "Dein Termin wurde abgesagt",
-          text: `Hallo ${booking.customerName},\n\nleider wurde dein Termin am ${formattedDate} um ${booking.appointmentTime} abgesagt. Bitte buche einen neuen Termin.\n\nRechtliche Informationen: ${generateUrl('/legal')}\nZur Website: ${homepageUrl}\n\nLiebe Grüße\nStargirlnails Kiel`,
+          text: `Hallo ${booking.customerName},\n\nleider wurde dein Termin am ${formattedDate} um ${booking.appointmentTime} abgesagt.\n\nBehandlungen:\n${treatmentsText}\n\nGesamt: ${totalDuration} Min, ${totalPrice.toFixed(2)} €\n\nBitte buche einen neuen Termin.\n\nRechtliche Informationen: ${generateUrl('/legal')}\nZur Website: ${homepageUrl}\n\nLiebe Grüße\nStargirlnails Kiel`,
           html,
           bcc: process.env.ADMIN_EMAIL ? [process.env.ADMIN_EMAIL] : undefined,
         });
@@ -504,11 +564,21 @@ const remove = os
       try {
         const formattedDate = formatDateGerman(booking.appointmentDate);
         const homepageUrl = generateUrl();
-        const html = await renderBookingCancelledHTML({ name: booking.customerName, date: booking.appointmentDate, time: booking.appointmentTime });
+        const html = await renderBookingCancelledHTML({ 
+          name: booking.customerName, 
+          date: booking.appointmentDate, 
+          time: booking.appointmentTime,
+          treatments: booking.treatments
+        });
+        
+        const treatmentsText = booking.treatments.map(t => `- ${t.name} (${t.duration} Min, ${t.price.toFixed(2)} €)`).join('\n');
+        const totalDuration = booking.treatments.reduce((sum, t) => sum + t.duration, 0);
+        const totalPrice = booking.treatments.reduce((sum, t) => sum + t.price, 0);
+        
         await sendEmail({
           to: booking.customerEmail,
           subject: "Dein Termin wurde abgesagt",
-          text: `Hallo ${booking.customerName},\n\nleider wurde dein Termin am ${formattedDate} um ${booking.appointmentTime} abgesagt. Bitte buche einen neuen Termin.\n\nRechtliche Informationen: ${generateUrl('/legal')}\nZur Website: ${homepageUrl}\n\nLiebe Grüße\nStargirlnails Kiel`,
+          text: `Hallo ${booking.customerName},\n\nleider wurde dein Termin am ${formattedDate} um ${booking.appointmentTime} abgesagt.\n\nBehandlungen:\n${treatmentsText}\n\nGesamt: ${totalDuration} Min, ${totalPrice.toFixed(2)} €\n\nBitte buche einen neuen Termin.\n\nRechtliche Informationen: ${generateUrl('/legal')}\nZur Website: ${homepageUrl}\n\nLiebe Grüße\nStargirlnails Kiel`,
           html,
           bcc: process.env.ADMIN_EMAIL ? [process.env.ADMIN_EMAIL] : undefined,
         });
@@ -524,7 +594,7 @@ const remove = os
 const createManual = os
   .input(z.object({
     sessionId: z.string(),
-    treatmentId: z.string(),
+    treatments: TreatmentsArraySchema,
     customerName: z.string().min(2, "Name muss mindestens 2 Zeichen lang sein"),
     customerEmail: z.string().email("Ungültige E-Mail-Adresse").optional(),
     customerPhone: z.string().min(5, "Telefonnummer muss mindestens 5 Zeichen lang sein").optional(),
@@ -557,37 +627,45 @@ const createManual = os
       }
     }
 
-    // Get treatment duration for validation
-    const treatment = await treatmentsKV.getItem(input.treatmentId);
-    if (!treatment) {
-      throw new Error("Behandlung nicht gefunden.");
+    // Validate all treatments exist and snapshot them from KV
+    const snapshottedTreatments = [] as Array<{id: string; name: string; duration: number; price: number}>;
+    for (const inputTreatment of input.treatments) {
+      const treatment = await treatmentsKV.getItem(inputTreatment.id);
+      if (!treatment) {
+        throw new Error(`Behandlung "${inputTreatment.name}" nicht gefunden.`);
+      }
+      // Verify snapshot data matches current treatment data
+      if (treatment.name !== inputTreatment.name || treatment.duration !== inputTreatment.duration || treatment.price !== inputTreatment.price) {
+        throw new Error(`Behandlungsdaten für "${inputTreatment.name}" stimmen nicht überein. Bitte lade die Seite neu.`);
+      }
+      snapshottedTreatments.push({ id: treatment.id, name: treatment.name, duration: treatment.duration, price: treatment.price });
     }
+    const totalDuration = snapshottedTreatments.reduce((sum, t) => sum + t.duration, 0);
 
     // Validate booking time against recurring rules
     await validateBookingAgainstRules(
       input.appointmentDate,
       input.appointmentTime,
-      treatment.duration
+      totalDuration
     );
 
     // Check for booking conflicts
     await checkBookingConflicts(
       input.appointmentDate,
       input.appointmentTime,
-      treatment.duration
+      totalDuration
     );
 
     const id = randomUUID();
     const booking = {
       id,
-      treatmentId: input.treatmentId,
+      treatments: snapshottedTreatments,
       customerName: input.customerName,
       customerEmail: input.customerEmail,
       customerPhone: input.customerPhone,
       appointmentDate: input.appointmentDate,
       appointmentTime: input.appointmentTime,
       notes: input.notes,
-      bookedDurationMinutes: treatment.duration,
       status: "confirmed" as const,
       createdAt: new Date().toISOString()
     } as Booking;
@@ -611,20 +689,24 @@ const createManual = os
             date: input.appointmentDate,
             time: input.appointmentTime,
             cancellationUrl: bookingUrl,
-            reviewUrl: generateUrl(`/review/${bookingAccessToken.token}`)
+            reviewUrl: generateUrl(`/review/${bookingAccessToken.token}`),
+            treatments: input.treatments
           });
 
+          const treatmentsText = input.treatments.map(t => `- ${t.name} (${t.duration} Min, ${t.price.toFixed(2)} €)`).join('\n');
+          const totalPrice = input.treatments.reduce((sum, t) => sum + t.price, 0);
+
         await sendEmailWithAGBAndCalendar({
           to: input.customerEmail!,
           subject: "Dein Termin wurde bestätigt - AGB im Anhang",
-          text: `Hallo ${input.customerName},\n\nwir haben deinen Termin am ${formattedDate} um ${input.appointmentTime} bestätigt.\n\nWichtiger Hinweis: Die Allgemeinen Geschäftsbedingungen (AGB) findest du im Anhang dieser E-Mail. Bitte lies sie vor deinem Termin durch.\n\nTermin-Status ansehen und verwalten: ${bookingUrl}\nFalls du den Termin stornieren möchtest, kannst du das über den obigen Link tun.\n\nRechtliche Informationen: ${generateUrl('/legal')}\nZur Website: ${homepageUrl}\n\nBis bald!\nStargirlnails Kiel`,
+          text: `Hallo ${input.customerName},\n\nwir haben deinen Termin am ${formattedDate} um ${input.appointmentTime} bestätigt.\n\nBehandlungen:\n${treatmentsText}\n\nGesamt: ${totalDuration} Min, ${totalPrice.toFixed(2)} €\n\nWichtiger Hinweis: Die Allgemeinen Geschäftsbedingungen (AGB) findest du im Anhang dieser E-Mail. Bitte lies sie vor deinem Termin durch.\n\nTermin-Status ansehen und verwalten: ${bookingUrl}\nFalls du den Termin stornieren möchtest, kannst du das über den obigen Link tun.\n\nRechtliche Informationen: ${generateUrl('/legal')}\nZur Website: ${homepageUrl}\n\nBis bald!\nStargirlnails Kiel`,
           html,
         }, {
             date: input.appointmentDate,
             time: input.appointmentTime,
-            durationMinutes: treatment.duration,
             customerName: input.customerName,
-            treatmentName: treatment.name
+            customerEmail: input.customerEmail,
+            treatments: input.treatments
           });
         } catch (e) {
           console.error("Email send failed for manual booking:", e);
@@ -695,8 +777,10 @@ export const router = {
       if (!booking) throw new Error("Booking not found");
       if (booking.status !== "confirmed") throw new Error("Nur bestätigte Termine können umgebucht werden.");
 
-      const treatment = await treatmentsKV.getItem(booking.treatmentId);
-      if (!treatment) throw new Error("Behandlung nicht gefunden.");
+      // Calculate total duration from treatments array
+      const totalDuration = booking.treatments && booking.treatments.length > 0
+        ? booking.treatments.reduce((sum, t) => sum + t.duration, 0)
+        : (booking.bookedDurationMinutes || 60);
 
       // Validate grid and not in past
       const appointmentMinutes = parseTime(input.proposedTime);
@@ -715,8 +799,8 @@ export const router = {
         }
       }
 
-      await validateBookingAgainstRules(input.proposedDate, input.proposedTime, booking.bookedDurationMinutes || treatment.duration);
-      await checkBookingConflicts(input.proposedDate, input.proposedTime, booking.bookedDurationMinutes || treatment.duration, booking.id);
+      await validateBookingAgainstRules(input.proposedDate, input.proposedTime, totalDuration);
+      await checkBookingConflicts(input.proposedDate, input.proposedTime, totalDuration, booking.id);
 
       // Invalidate and create new reschedule token via cancellation router
       const res = await queryClient.cancellation.createRescheduleToken({
@@ -729,13 +813,16 @@ export const router = {
 
       // Send proposal email to customer
       if (booking.customerEmail) {
+        const treatmentName = booking.treatments && booking.treatments.length > 0
+          ? booking.treatments.map(t => t.name).join(', ')
+          : "Behandlung";
         const html = await renderBookingRescheduleProposalHTML({
           name: booking.customerName,
           originalDate: booking.appointmentDate,
           originalTime: booking.appointmentTime,
           proposedDate: input.proposedDate,
           proposedTime: input.proposedTime,
-          treatmentName: (await treatmentsKV.getItem(booking.treatmentId))?.name || "Behandlung",
+          treatmentName: treatmentName,
           acceptUrl,
           declineUrl,
           expiresAt: res.expiresAt,
@@ -761,8 +848,9 @@ export const router = {
       if (!booking) throw new Error("Booking not found");
       if (booking.status !== "confirmed") throw new Error("Buchung ist nicht mehr in bestätigtem Zustand.");
 
-      const treatment = await treatmentsKV.getItem(booking.treatmentId);
-      const duration = booking.bookedDurationMinutes || treatment?.duration || 60;
+      const duration = booking.treatments && booking.treatments.length > 0
+        ? booking.treatments.reduce((sum, t) => sum + t.duration, 0)
+        : (booking.bookedDurationMinutes || 60);
 
       // Re-validate slot to ensure still available
       await validateBookingAgainstRules(proposal.proposed.date, proposal.proposed.time, duration);
@@ -783,29 +871,37 @@ export const router = {
           time: updated.appointmentTime,
           cancellationUrl: generateUrl(`/booking/${bookingAccessToken.token}`),
           reviewUrl: generateUrl(`/review/${bookingAccessToken.token}`),
+          treatments: updated.treatments,
         });
+        
+        const treatmentsText = updated.treatments.map(t => `- ${t.name} (${t.duration} Min, ${t.price.toFixed(2)} €)`).join('\n');
+        const totalPrice = updated.treatments.reduce((sum, t) => sum + t.price, 0);
+        
         await sendEmailWithAGBAndCalendar({
           to: updated.customerEmail,
           subject: "Terminänderung bestätigt",
-          text: `Hallo ${updated.customerName}, dein neuer Termin ist am ${formatDateGerman(updated.appointmentDate)} um ${updated.appointmentTime}.`,
+          text: `Hallo ${updated.customerName}, dein neuer Termin ist am ${formatDateGerman(updated.appointmentDate)} um ${updated.appointmentTime}.\n\nBehandlungen:\n${treatmentsText}\n\nGesamt: ${duration} Min, ${totalPrice.toFixed(2)} €`,
           html,
         }, {
           date: updated.appointmentDate,
           time: updated.appointmentTime,
-          durationMinutes: duration,
           customerName: updated.customerName,
-          treatmentName: (await treatmentsKV.getItem(updated.treatmentId))?.name || "Behandlung",
+          customerEmail: updated.customerEmail,
+          treatments: updated.treatments,
         }).catch(() => {});
       }
 
       if (process.env.ADMIN_EMAIL) {
+        const treatmentName = updated.treatments && updated.treatments.length > 0
+          ? updated.treatments.map(t => t.name).join(', ')
+          : "Behandlung";
         const adminHtml = await renderAdminRescheduleAcceptedHTML({
           customerName: updated.customerName,
           originalDate: proposal.original.date,
           originalTime: proposal.original.time,
           newDate: updated.appointmentDate,
           newTime: updated.appointmentTime,
-          treatmentName: (await treatmentsKV.getItem(updated.treatmentId))?.name || "Behandlung",
+          treatmentName: treatmentName,
         });
         await sendEmail({
           to: process.env.ADMIN_EMAIL,
@@ -832,23 +928,38 @@ export const router = {
       // Notify customer that original stays
       if (booking.customerEmail) {
         const bookingAccessToken = await queryClient.cancellation.createToken({ bookingId: booking.id });
+        
+        const treatmentsText = booking.treatments.map(t => `- ${t.name} (${t.duration} Min, ${t.price.toFixed(2)} €)`).join('\n');
+        const totalDuration = booking.treatments.reduce((sum, t) => sum + t.duration, 0);
+        const totalPrice = booking.treatments.reduce((sum, t) => sum + t.price, 0);
+        
         await sendEmail({
           to: booking.customerEmail,
           subject: "Terminänderung abgelehnt",
-          text: `Du hast den Vorschlag zur Terminänderung abgelehnt. Dein ursprünglicher Termin am ${formatDateGerman(booking.appointmentDate)} um ${booking.appointmentTime} bleibt bestehen.`,
-          html: await renderBookingConfirmedHTML({ name: booking.customerName, date: booking.appointmentDate, time: booking.appointmentTime, cancellationUrl: generateUrl(`/booking/${bookingAccessToken.token}`), reviewUrl: generateUrl(`/review/${bookingAccessToken.token}`) }),
+          text: `Du hast den Vorschlag zur Terminänderung abgelehnt. Dein ursprünglicher Termin am ${formatDateGerman(booking.appointmentDate)} um ${booking.appointmentTime} bleibt bestehen.\n\nBehandlungen:\n${treatmentsText}\n\nGesamt: ${totalDuration} Min, ${totalPrice.toFixed(2)} €`,
+          html: await renderBookingConfirmedHTML({ 
+            name: booking.customerName, 
+            date: booking.appointmentDate, 
+            time: booking.appointmentTime, 
+            cancellationUrl: generateUrl(`/booking/${bookingAccessToken.token}`), 
+            reviewUrl: generateUrl(`/review/${bookingAccessToken.token}`),
+            treatments: booking.treatments
+          }),
         }).catch(() => {});
       }
 
       // Notify admin
       if (process.env.ADMIN_EMAIL) {
+        const treatmentName = booking.treatments && booking.treatments.length > 0
+          ? booking.treatments.map(t => t.name).join(', ')
+          : "Behandlung";
         const html = await renderAdminRescheduleDeclinedHTML({
           customerName: booking.customerName,
           originalDate: proposal.original.date,
           originalTime: proposal.original.time,
           proposedDate: proposal.proposed.date!,
           proposedTime: proposal.proposed.time!,
-          treatmentName: (await treatmentsKV.getItem(booking.treatmentId))?.name || "Behandlung",
+          treatmentName: treatmentName,
           customerEmail: booking.customerEmail,
           customerPhone: booking.customerPhone,
         });
@@ -938,8 +1049,9 @@ export const router = {
       }
       
       // Get treatment name for context
-      const treatment = await treatmentsKV.getItem(booking.treatmentId);
-      const treatmentName = treatment?.name || "Behandlung";
+      const treatmentName = booking.treatments && booking.treatments.length > 0
+        ? booking.treatments.map(t => t.name).join(', ')
+        : "Behandlung";
       
       // Prepare email with Reply-To header
       const ownerName = process.env.OWNER_NAME || "Stargirlnails Kiel";

src/server/rpc/recurring-availability.ts

@@ -272,7 +272,12 @@ const getAvailableTimes = os
   .input(
     z.object({
       date: z.string().regex(/^\d{4}-\d{2}-\d{2}$/),
-      treatmentId: z.string(),
+      treatmentIds: z.array(z.string())
+        .min(1, "Mindestens eine Behandlung muss ausgewählt werden")
+        .max(3, "Maximal 3 Behandlungen können ausgewählt werden")
+        .refine(list => {
+          return list.length === new Set(list).size;
+        }, { message: "Doppelte Behandlungen sind nicht erlaubt" }),
     })
   )
   .handler(async ({ input }) => {
@@ -287,13 +292,22 @@ const getAvailableTimes = os
         return [];
       }
       
-      // Get treatment duration
-      const treatment = await treatmentsKV.getItem(input.treatmentId);
-      if (!treatment) {
-        throw new Error("Behandlung nicht gefunden.");
+      // Get multiple treatments and calculate total duration
+      const treatments = await Promise.all(
+        input.treatmentIds.map(id => treatmentsKV.getItem(id))
+      );
+      
+      // Validate that all treatments exist
+      const missingTreatments = treatments
+        .map((t, i) => t ? null : input.treatmentIds[i])
+        .filter(id => id !== null);
+      
+      if (missingTreatments.length > 0) {
+        throw new Error(`Behandlung(en) nicht gefunden: ${missingTreatments.join(', ')}`);
       }
       
-      const treatmentDuration = treatment.duration;
+      // Calculate total duration by summing all treatment durations
+      const treatmentDuration = treatments.reduce((sum, t) => sum + (t?.duration || 0), 0);
       
       // Parse the date to get day of week
       const [year, month, day] = input.date.split('-').map(Number);
@@ -344,36 +358,38 @@ const getAvailableTimes = os
         ['pending', 'confirmed', 'completed'].includes(booking.status)
       );
       
-      // Optimize treatment duration lookup with Map caching
-      const uniqueTreatmentIds = [...new Set(dateBookings.map(booking => booking.treatmentId))];
+      // Build cache only for legacy treatmentId bookings
+      const legacyTreatmentIds = [...new Set(dateBookings.filter(b => b.treatmentId).map(b => b.treatmentId as string))];
       const treatmentDurationMap = new Map<string, number>();
       
-      for (const treatmentId of uniqueTreatmentIds) {
-        const treatment = await treatmentsKV.getItem(treatmentId);
-        treatmentDurationMap.set(treatmentId, treatment?.duration || 60);
-      }
-      
-      // Get treatment durations for all bookings using the cached map
-      const bookingTreatments = new Map();
-      for (const booking of dateBookings) {
-        // Use bookedDurationMinutes if available, otherwise fallback to treatment duration
-        const duration = booking.bookedDurationMinutes || treatmentDurationMap.get(booking.treatmentId) || 60;
-        bookingTreatments.set(booking.id, duration);
+      // Only build cache if there are legacy bookings
+      if (legacyTreatmentIds.length > 0) {
+        for (const id of legacyTreatmentIds) {
+          const t = await treatmentsKV.getItem(id);
+          treatmentDurationMap.set(id, t?.duration || 60);
+        }
       }
       
       // Filter out booking conflicts
       const availableTimesFiltered = availableTimes.filter(slotTime => {
         const slotStartMinutes = parseTime(slotTime);
-        const slotEndMinutes = slotStartMinutes + treatmentDuration;
+        const slotEndMinutes = slotStartMinutes + treatmentDuration; // total from selected treatments
         
-        // Check if this slot overlaps with any existing booking
         const hasConflict = dateBookings.some(booking => {
-          const bookingStartMinutes = parseTime(booking.appointmentTime);
-          const bookingDuration = bookingTreatments.get(booking.id) || 60;
-          const bookingEndMinutes = bookingStartMinutes + bookingDuration;
+          let bookingDuration: number;
+          if (booking.treatments && booking.treatments.length > 0) {
+            bookingDuration = booking.treatments.reduce((sum: number, t: { duration: number }) => sum + t.duration, 0);
+          } else if (booking.bookedDurationMinutes) {
+            bookingDuration = booking.bookedDurationMinutes;
+          } else if (booking.treatmentId) {
+            bookingDuration = treatmentDurationMap.get(booking.treatmentId) || 60;
+          } else {
+            bookingDuration = 60;
+          }
           
-          // Check overlap: slotStart < bookingEnd && slotEnd > bookingStart
-          return slotStartMinutes < bookingEndMinutes && slotEndMinutes > bookingStartMinutes;
+          const bookingStart = parseTime(booking.appointmentTime);
+          const bookingEnd = bookingStart + bookingDuration;
+          return slotStartMinutes < bookingEnd && slotEndMinutes > bookingStart;
         });
         
         return !hasConflict;