chore: bump version to v0.8.17

- Added `remove_done` function to clean up finished appointments in the database.
- Introduced `get_upcoming_for_user` function to retrieve upcoming appointments for a specific user.
- Updated `backend_server.py` to include a new endpoint for fetching user-specific upcoming events.
- Modified `blueprint.py` to render upcoming events in the user interface.
- Enhanced `terminplan.html` to display a list of upcoming appointments with relevant details and action links.
- Updated configuration to enable the new appointment planning feature.

.release-version

@@ -1 +1 @@
-v0.8.9
+v0.8.17

Web/app.py

@@ -84,7 +84,7 @@ from Web.modules.terminplaner.blueprint import appoint_bp as terminplaner_bp
 BASE_DIR = os.path.dirname(os.path.abspath(__file__))
 import Web.modules.database.settings as cfg
 from Web.modules.database.settings import MongoClient
-from tenant import get_tenant_context, get_tenant_trial_status, purge_expired_trial_tenants
+from tenant import get_tenant_context, get_tenant_db, get_tenant_trial_status, purge_expired_trial_tenants
 
 
 app = Flask(__name__, static_folder='static')  # Correctly set static folder
@@ -626,14 +626,18 @@ def handle_unexpected_exception(e):
     if request.is_json or request.path.startswith('/api/'):
         return jsonify({'error': 'Internal server error', 'status': 500}), 500
 
-    if 'username' in session:
+    try:
+        return render_template(
+            'maintenance.html',
+            error_code=500,
+            error_message='Das System führt gerade Wartungsarbeiten durch.',
+        ), 500
+    except Exception:
         try:
-            return render_template('error.html', error_code=500, error_message='Interner Serverfehler.'), 500
+            return render_template('error.html', error_code=500, error_message='Das System führt gerade Wartungsarbeiten durch.'), 500
         except Exception:
             return 'Internal Server Error', 500
 
-    return redirect(url_for('login'))
-
 
 def _csrf_error_response(message='CSRF token fehlt oder ist ungültig.'):
     if request.is_json or request.path.startswith('/api/') or request.path in {'/download_book_cover', '/proxy_image', '/log_mobile_issue'}:
@@ -4799,6 +4803,82 @@ def get_bookings():
             client.close()
 
 
+@app.route('/get_user_appointments')
+def get_user_appointments():
+    """Return the current user's planned and active appointments for the calendar."""
+    if 'username' not in session:
+        return jsonify({'ok': False, 'error': 'unauthorized'}), 401
+
+    client = None
+    try:
+        username = session.get('username')
+
+        client = MongoClient(MONGODB_HOST, MONGODB_PORT)
+        db = client[MONGODB_DB]
+        items_col = db['items']
+
+        # Use the established user-specific route logic for appointments.
+        bookings = au.get_ausleihung_by_user(
+            username,
+            status=['planned', 'active', 'completed'],
+            use_client_side_verification=True,
+        )
+        bookings = sorted(bookings, key=lambda b: b.get('Start') or datetime.datetime.min)
+
+        result = []
+        for booking in bookings:
+            start_dt = booking.get('Start')
+            if not start_dt:
+                continue
+
+            end_dt = booking.get('End')
+            if not end_dt and isinstance(start_dt, datetime.datetime):
+                end_dt = start_dt + datetime.timedelta(minutes=45)
+            elif not end_dt:
+                end_dt = start_dt
+
+            item_id = str(booking.get('Item') or '')
+            item_doc = None
+            if item_id:
+                try:
+                    item_doc = items_col.find_one({'_id': ObjectId(item_id)})
+                except Exception:
+                    item_doc = None
+
+            item_name = item_id or 'Termin'
+            if item_doc:
+                item_name = item_doc.get('Name') or item_doc.get('Code_4') or item_name
+
+            period = booking.get('Period')
+            title = item_name
+            if period:
+                title = f"{title} - {period}. Std"
+
+            status = booking.get('VerifiedStatus') or booking.get('Status') or 'unknown'
+            if status == 'active':
+                status = 'current'
+            result.append({
+                'id': str(booking.get('_id')),
+                'title': title,
+                'start': start_dt.isoformat() if isinstance(start_dt, datetime.datetime) else str(start_dt),
+                'end': end_dt.isoformat() if isinstance(end_dt, datetime.datetime) else str(end_dt),
+                'status': status,
+                'itemId': item_id,
+                'userName': str(booking.get('User') or ''),
+                'notes': str(booking.get('Notes') or ''),
+                'period': period,
+                'isCurrentUser': True,
+                'itemBorrower': '',
+            })
+
+        return jsonify({'ok': True, 'bookings': result})
+    except Exception as e:
+        return jsonify({'ok': False, 'error': str(e), 'bookings': []}), 500
+    finally:
+        if client:
+            client.close()
+
+
 @app.route('/api/booking_conflicts')
 def api_booking_conflicts():
     """

Web/modules/database/termine.py

@@ -22,6 +22,14 @@ from Web.modules.database.settings import MongoClient
 from bson.objectid import ObjectId
 import datetime 
 
+
+def _get_tenant_db(client):
+    try:
+        from tenant import get_tenant_db
+        return get_tenant_db(client)
+    except Exception:
+        return client[cfg.MONGODB_DB]
+
 def _active_record_query(extra_query=None):
     """Build a query that excludes logically deleted records."""
     base_query = {'Deleted': {'$ne': True}}
@@ -30,10 +38,10 @@ def _active_record_query(extra_query=None):
     return base_query
 
 
-def add(date_start: str, date_end: str, time_span: list, slots: int, slot_lenght: int, user: str, mail: list=[], note:str=""):
+def add(date_start: str, date_end: str, time_span: list, slots: int, slot_lenght: int, user: str, mail: list=[], note:str="", calendar_enabled: bool=False):
     try:
         client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
-        db = client[cfg.MONGODB_DB]
+        db = _get_tenant_db(client)
         items = db['appointments']
 
         item = {
@@ -45,6 +53,7 @@ def add(date_start: str, date_end: str, time_span: list, slots: int, slot_lenght
             'user': user,
             'mail': mail,
             'note': note,
+            'calendar_enabled': bool(calendar_enabled),
             'slots_booked': [], # -> [(start_time, name), ...]the list gets there indexes as the slot 1-defined so is can be counted without an extra variable
             'Created': datetime.datetime.now(),
             'LastUpdated': datetime.datetime.now()
@@ -67,7 +76,7 @@ def get_item(id):
     """
     try:
         client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
-        db = client[cfg.MONGODB_DB]
+        db = _get_tenant_db(client)
         items = db['appointments']
         item = items.find_one(_active_record_query({'_id': ObjectId(id)}))
         client.close()
@@ -89,11 +98,11 @@ def update(id,slots_used: list):
     """
     try:
         client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
-        db = client[cfg.MONGODB_DB]
+        db = _get_tenant_db(client)
         items = db['appointments']
 
         update_data = {
-            'slots_booked': [slots_used],
+            'slots_booked': slots_used,
             'LastUpdated': datetime.datetime.now()
         }
 
@@ -123,7 +132,7 @@ def remove_slot(id, date_start_time, name):
     """
     try:
         client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
-        db = client[cfg.MONGODB_DB]
+        db = _get_tenant_db(client)
         items = db['appointments']
 
         # Attempt to pull the exact element (stored as an array/tuple)
@@ -151,15 +160,75 @@ def remove(id):
     """
     try:
         client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
-        db = client[cfg.MONGODB_DB]
+        db = _get_tenant_db(client)
         items = db['appointments']
 
         result = items.delete_one({'_id': ObjectId(id)})
 
         client.close()
-        return result.modified_count > 0
+        return result.deleted_count > 0
     except Exception as e:
         print(f"Error removing appointment: {e}")
         return False
 
+def remove_done():
+    """removose already finisched appointments"""
+    try:
+        client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
+        db = _get_tenant_db(client)
+        items = db['appointments']
+
+        today = datetime.date.today().strftime('%Y-%m-%d')
+        removed_count = 0
+
+        cursor = items.find(
+            _active_record_query(
+                {
+                    'date_end': {'$lt': today},
+                }
+            )
+        ).sort('date_start', 1)
+
+        for item in cursor:
+            item['_id'] = str(item.get('_id'))
+            result = items.delete_one({'_id': ObjectId(item['_id'])})
+            removed_count += result.deleted_count
+        
+        client.close()
+        return removed_count > 0
+    except Exception as e:
+        print(f"Error removing appointment: {e}")
+        return False
+
+def get_upcoming_for_user(user: str, limit: int = 25):
+    """Return upcoming appointment plans for a user ordered by start date."""
+    remove_done()
+    try:
+        client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
+        db = _get_tenant_db(client)
+        items = db['appointments']
+
+        today = datetime.date.today().strftime('%Y-%m-%d')
+        cursor = items.find(
+            _active_record_query(
+                {
+                    'user': str(user or '').strip(),
+                    'date_end': {'$gte': today},
+                }
+            )
+        ).sort('date_start', 1)
+
+        results = []
+        for item in cursor:
+            item['_id'] = str(item.get('_id'))
+            results.append(item)
+            if len(results) >= max(1, int(limit)):
+                break
+
+        client.close()
+        return results
+    except Exception as e:
+        print(f"Error retrieving upcoming appointments: {e}")
+        return []
+
  

Web/modules/terminplaner/backend_server.py

@@ -2,12 +2,40 @@
 Class for all funktions of the executive -> Lehrer
 """
 import datetime
+from datetime import timedelta
+from flask import url_for, has_request_context, request
 import Web.modules.emailservice.email as mail_service
 import Web.modules.database.termine as termin
 import Web.modules.database.settings as cfg
 from Web.tenant import get_tenant_context
 
 
+def _resolve_public_base_url() -> str:
+    if has_request_context():
+        try:
+            return request.url_root.rstrip('/')
+        except Exception:
+            pass
+
+    tenant_context = get_tenant_context()
+    subdomain = ''
+    if tenant_context:
+        subdomain = getattr(tenant_context, 'subdomain', '') or getattr(tenant_context, 'tenant_id', '') or ''
+    return f"https://{subdomain}.invario.eu" if subdomain else "https://invario.eu"
+
+
+def _current_tenant_id() -> str:
+    tenant_context = get_tenant_context()
+    if tenant_context and getattr(tenant_context, 'tenant_id', None):
+        return str(tenant_context.tenant_id)
+    if has_request_context():
+        try:
+            return str(request.args.get('tenant', '') or request.args.get('tenant_id', '') or '').strip()
+        except Exception:
+            return ''
+    return ''
+
+
 def _normalize_time_span(time_span):
     if isinstance(time_span, list):
         return [str(entry).strip() for entry in time_span if str(entry).strip()]
@@ -32,7 +60,77 @@ def _normalize_mail_list(mail):
         return [entry.strip() for entry in mail.replace(';', ',').split(',') if entry.strip()]
     return []
 
-def new(date_start: str, date_end: str, time_span: list, slots: int, slot_lenght: int, user: str, mail: list=[], note:str="") -> str:
+def _escape_ics_text(value):
+    return str(value or '').replace('\\', '\\\\').replace(';', '\\;').replace(',', '\\,').replace('\r\n', '\n').replace('\n', '\\n').replace('\r', '')
+
+
+def _format_ics_date(date_value):
+    if isinstance(date_value, datetime.datetime):
+        return date_value.strftime('%Y%m%dT%H%M%SZ')
+    if isinstance(date_value, datetime.date):
+        return date_value.strftime('%Y%m%d')
+    return ''
+
+
+def build_calendar_ics(appointment_id: str) -> str | None:
+    item = termin.get_item(appointment_id)
+    if not item:
+        return None
+
+    date_start = item.get('date_start')
+    date_end = item.get('date_end')
+    time_span = item.get('time_span', []) or []
+    creator = item.get('user', 'Terminplaner')
+    note = item.get('note', '') or ''
+    tenant_id = _current_tenant_id()
+    try:
+        link = url_for('terminplaner.client', appointment_id=str(appointment_id), tenant=tenant_id or None, _external=True)
+    except Exception:
+        host = _resolve_public_base_url()
+        link = host + "/terminplaner/client/" + str(appointment_id)
+        if tenant_id:
+            link += f"?tenant={tenant_id}"
+
+    try:
+        start_date = datetime.datetime.strptime(str(date_start), '%Y-%m-%d').date()
+        end_date = datetime.datetime.strptime(str(date_end), '%Y-%m-%d').date()
+    except Exception:
+        return None
+
+    uid = f"terminplaner-{appointment_id}@invario.eu"
+    created_at = datetime.datetime.utcnow().strftime('%Y%m%dT%H%M%SZ')
+    summary = f"Terminplan für {creator}"
+    description_lines = [
+        f"Buchungslink: {link}",
+        f"Zeitraum: {date_start} bis {date_end}",
+    ]
+    if time_span:
+        description_lines.append('Zeitfenster: ' + '; '.join(str(entry) for entry in time_span))
+    if note:
+        description_lines.append('Notiz: ' + str(note))
+
+    ics_lines = [
+        'BEGIN:VCALENDAR',
+        'VERSION:2.0',
+        'PRODID:-//Inventarsystem//Terminplaner//DE',
+        'CALSCALE:GREGORIAN',
+        'METHOD:PUBLISH',
+        'BEGIN:VEVENT',
+        f'UID:{uid}',
+        f'DTSTAMP:{created_at}',
+        f'SUMMARY:{_escape_ics_text(summary)}',
+        f'DESCRIPTION:{_escape_ics_text(chr(10).join(description_lines))}',
+        f'URL:{_escape_ics_text(link)}',
+        f'DTSTART;VALUE=DATE:{_format_ics_date(start_date)}',
+        f'DTEND;VALUE=DATE:{_format_ics_date(end_date + timedelta(days=1))}',
+        'END:VEVENT',
+        'END:VCALENDAR',
+        '',
+    ]
+    return '\r\n'.join(ics_lines)
+
+
+def new(date_start: str, date_end: str, time_span: list, slots: int, slot_lenght: int, user: str, mail: list=[], note:str="", calendar_enabled: bool=False) -> dict:
     """
     Generates a link for the executive to send to his clients to book a time Slot
     
@@ -48,21 +146,41 @@ def new(date_start: str, date_end: str, time_span: list, slots: int, slot_lenght
     """
     normalized_time_span = _normalize_time_span(time_span)
     normalized_mail = _normalize_mail_list(mail)
-    id = termin.add(date_start, date_end, normalized_time_span, slots, slot_lenght, user, normalized_mail, note)
+    id = termin.add(date_start, date_end, normalized_time_span, slots, slot_lenght, user, normalized_mail, note, calendar_enabled=calendar_enabled)
     id_str = str(id)
+    tenant_id = _current_tenant_id()
 
-    tenant_context = get_tenant_context()
-    subdomain = ''
-    if tenant_context:
-        subdomain = getattr(tenant_context, 'subdomain', '') or getattr(tenant_context, 'tenant_id', '') or ''
-
-    host = f"https://{subdomain}.invario.eu" if subdomain else "invario.eu"
-    link = host + "/terminplaner/client" + "?" + "client_id=" + id_str
+    try:
+        link = url_for('terminplaner.client', appointment_id=id_str, tenant=tenant_id or None, _external=True)
+    except Exception:
+        host = _resolve_public_base_url()
+        link = host + "/terminplaner/client/" + id_str
+        if tenant_id:
+            link += f"?tenant={tenant_id}"
     subject = f"Terminanfrage von {user}"
     note_link = note + f"Bitte klicken sie auf den folgenden Link um einen Termin zu vereinbaren: {link}"
-    if normalized_mail:
-        mail_service.send(normalized_mail, subject, note_link)
-    return link
+    calendar_link = None
+    if calendar_enabled:
+        try:
+            calendar_link = url_for('terminplaner.calendar_export', appointment_id=id_str, tenant=tenant_id or None, _external=True)
+        except Exception:
+            host = _resolve_public_base_url()
+            calendar_link = host + "/terminplaner/calendar/" + id_str + ".ics"
+            if tenant_id:
+                calendar_link += f"?tenant={tenant_id}"
+
+    email_body = note_link
+    if calendar_link:
+        email_body += f"\n\nKalendereintrag: {calendar_link}"
+
+    if normalized_mail and cfg.EMAIL_ENABLED:
+        mail_service.send(normalized_mail, subject, email_body)
+
+    return {
+        'appointment_id': id_str,
+        'link': link,
+        'calendar_link': calendar_link,
+    }
     
         
 def book_slot(id, date_start_time, name):
@@ -215,4 +333,57 @@ def get_available_user(id):
     - dict: all the needet information -> [Start_date, End_date, (first day Time Frame, 
     second day Time frame, third etc.), slot lenght, (bookedslots -> list)]
     """
-    return get_available(id)
+    return get_available(id)
+
+
+def get_user_upcoming_events(user: str, limit: int = 25) -> list[dict]:
+    """Return upcoming appointment plans for overview display."""
+    user_name = str(user or '').strip()
+    if not user_name:
+        return []
+
+    appointments = termin.get_upcoming_for_user(user_name, limit=limit)
+    host = _resolve_public_base_url()
+    tenant_id = _current_tenant_id()
+
+    result = []
+    for item in appointments:
+        appointment_id = str(item.get('_id') or '')
+        if not appointment_id:
+            continue
+
+        try:
+            link = url_for('terminplaner.client', appointment_id=appointment_id, tenant=tenant_id or None, _external=True)
+        except Exception:
+            link = host + '/terminplaner/client/' + appointment_id
+            if tenant_id:
+                link += f'?tenant={tenant_id}'
+
+        try:
+            calendar_link = url_for('terminplaner.calendar_export', appointment_id=appointment_id, tenant=tenant_id or None, _external=True)
+        except Exception:
+            calendar_link = host + '/terminplaner/calendar/' + appointment_id + '.ics'
+            if tenant_id:
+                calendar_link += f'?tenant={tenant_id}'
+
+        slots_total = int(item.get('slots', 0) or 0)
+        slots_booked = item.get('slots_booked', []) or []
+        if not isinstance(slots_booked, list):
+            slots_booked = []
+
+        result.append(
+            {
+                'appointment_id': appointment_id,
+                'date_start': str(item.get('date_start') or ''),
+                'date_end': str(item.get('date_end') or ''),
+                'time_span': item.get('time_span', []) or [],
+                'slots_total': slots_total,
+                'slots_booked': len(slots_booked),
+                'slots_left': max(0, slots_total - len(slots_booked)),
+                'note': str(item.get('note') or ''),
+                'link': link,
+                'calendar_link': calendar_link if item.get('calendar_enabled') else None,
+            }
+        )
+
+    return result

Web/modules/terminplaner/blueprint.py

@@ -1,6 +1,9 @@
 from flask import Blueprint, render_template, request, session, url_for, redirect, flash
+from flask import Response
 import Web.modules.terminplaner.backend_server as appointment_service
 import Web.modules.database.settings as cfg
+import Web.modules.database.termine as termin
+import Web.modules.database.user as us
 
 # Create a blueprint instance
 appoint_bp = Blueprint('terminplaner', __name__)
@@ -12,6 +15,25 @@ def _require_module_enabled():
         return redirect(url_for('home'))
     return None
 
+
+def _appointment_not_found_response():
+    return render_template(
+        'terminplaner_not_found.html',
+        error_code=404,
+        error_message='Der Termin wurde nicht gefunden.',
+    ), 404
+
+
+def _current_tenant_id():
+    try:
+        from Web.tenant import get_tenant_context
+        ctx = get_tenant_context()
+        if ctx and getattr(ctx, 'tenant_id', None):
+            return str(ctx.tenant_id)
+    except Exception:
+        pass
+    return str(session.get('tenant_id', '') or '').strip()
+
 @appoint_bp.route('/client/<appointment_id>', methods=['POST', 'GET'])
 def client(appointment_id):
     """
@@ -23,8 +45,7 @@ def client(appointment_id):
 
     available = appointment_service.get_available(appointment_id)
     if not available:
-        flash('Der Termin wurde nicht gefunden.', 'error')
-        return redirect(url_for('terminplan'))
+        return _appointment_not_found_response()
 
     if request.method == 'POST':
         start_daytime = request.form.get('start_day_time')
@@ -49,8 +70,37 @@ def client(appointment_id):
         appointment_id=appointment_id,
         available=available,
         current_user=session.get('username', ''),
+        tenant_id=_current_tenant_id(),
     )
 
+
+@appoint_bp.route('/delete/<appointment_id>', methods=['POST'])
+def delete_appointment(appointment_id):
+    guard = _require_module_enabled()
+    if guard:
+        return guard
+
+    if 'username' not in session:
+        flash('Bitte mit einem Konto anmelden.', 'error')
+        return redirect(url_for('login'))
+
+    appointment = termin.get_item(appointment_id)
+    if not appointment:
+        return _appointment_not_found_response()
+
+    current_user = str(session.get('username', '')).strip()
+    appointment_user = str(appointment.get('user', '')).strip()
+    if not us.check_admin(current_user) and appointment_user != current_user:
+        flash('Sie dürfen diesen Termin nicht löschen.', 'error')
+        return redirect(url_for('terminplaner.main', tenant=_current_tenant_id() or None))
+
+    if termin.remove(appointment_id):
+        flash('Der Terminplan wurde gelöscht.', 'success')
+    else:
+        flash('Der Terminplan konnte nicht gelöscht werden.', 'error')
+
+    return redirect(url_for('terminplaner.main', tenant=_current_tenant_id() or None))
+
 @appoint_bp.route('/configure', methods=['GET', 'POST'])
 def configure():
     """
@@ -72,16 +122,51 @@ def configure():
         slot_lenght = request.form.get('slot_lenght')
         mail = request.form.get('mail', '')
         note = request.form.get('note', '')
+        add_to_calendar = request.form.get('add_to_calendar') == 'on'
 
         if not start or not end or not time or not slots_amount or not slot_lenght:
             flash('Bitte alle Pflichtfelder ausfüllen.', 'error')
-            return render_template('termin_configure.html', school_periods=cfg.SCHOOL_PERIODS, generated_link=None)
+            return render_template(
+                'termin_configure.html',
+                school_periods=cfg.SCHOOL_PERIODS,
+                generated_link=None,
+                email_service_enabled=cfg.EMAIL_ENABLED,
+            )
 
-        link = appointment_service.new(start, end, time, slots_amount, slot_lenght, session["username"], mail, note)
+        result = appointment_service.new(start, end, time, slots_amount, slot_lenght, session["username"], mail, note, calendar_enabled=add_to_calendar)
         flash('Der Terminplan wurde angelegt.', 'success')
-        return render_template('termin_configure.html', school_periods=cfg.SCHOOL_PERIODS, generated_link=link)
+        return render_template(
+            'termin_configure.html',
+            school_periods=cfg.SCHOOL_PERIODS,
+            generated_link=result['link'],
+            calendar_link=result.get('calendar_link'),
+            add_to_calendar=add_to_calendar,
+            email_service_enabled=cfg.EMAIL_ENABLED,
+        )
     elif request.method == "GET":
-        return render_template('termin_configure.html', school_periods=cfg.SCHOOL_PERIODS, generated_link=None)
+        return render_template(
+            'termin_configure.html',
+            school_periods=cfg.SCHOOL_PERIODS,
+            generated_link=None,
+            calendar_link=None,
+            add_to_calendar=False,
+            email_service_enabled=cfg.EMAIL_ENABLED,
+        )
+
+
+@appoint_bp.route('/calendar/<appointment_id>.ics', methods=['GET'])
+def calendar_export(appointment_id):
+    guard = _require_module_enabled()
+    if guard:
+        return guard
+
+    ics_content = appointment_service.build_calendar_ics(appointment_id)
+    if not ics_content:
+        return _appointment_not_found_response()
+
+    response = Response(ics_content, mimetype='text/calendar; charset=utf-8')
+    response.headers['Content-Disposition'] = f'attachment; filename=terminplan-{appointment_id}.ics'
+    return response
 
 @appoint_bp.route('/')
 def main():
@@ -89,8 +174,14 @@ def main():
     if guard:
         return guard
 
+    current_user = session.get('username', '')
+    upcoming_events = appointment_service.get_user_upcoming_events(current_user) if current_user else []
+    tenant_id = _current_tenant_id()
+
     return render_template(
         'terminplaner.html',
         school_periods=cfg.SCHOOL_PERIODS,
-        current_user=session.get('username', ''),
+        current_user=current_user,
+        upcoming_events=upcoming_events,
+        tenant_id=tenant_id,
     )

Web/templates/main.html

@@ -269,23 +269,6 @@
         line-height: 1;
     }
 
-    /* Compact appointment badge on cards */
-    .appointment-badge {
-        margin-top: 10px;
-        padding: 10px 12px;
-        background-color: #e1f5fe;
-        border-left: 4px solid #03a9f4;
-        border-radius: 4px;
-        font-size: 0.9rem;
-        line-height: 1.3;
-    }
-    .appointment-badge .appointment-time {
-        display: inline-block;
-        margin-top: 4px;
-        color: #01579b;
-        font-weight: 600;
-    }
-
     /* Search styles */
     .search-container {
         display: flex;
@@ -1006,23 +989,6 @@
                                 </div>`;
                         }
                         
-                        // Add appointment badge if item has upcoming appointments
-                        let appointmentBadge = '';
-                        if (item.appointments && Array.isArray(item.appointments) && item.appointments.length > 0) {
-                            const upcomingAppointment = getUpcomingAppointment(item.appointments);
-                            if (upcomingAppointment) {
-                                const formattedDate = formatAppointmentDate(upcomingAppointment.date);
-                                const startPeriod = formatAppointmentPeriod(upcomingAppointment.start_period);
-                                const endPeriod = formatAppointmentPeriod(upcomingAppointment.end_period);
-                                
-                                appointmentBadge = `
-                                    <div class="appointment-badge">
-                                        <strong>Geplant für:</strong> ${formattedDate}<br>
-                                        <span class="appointment-time">${startPeriod}${endPeriod && endPeriod !== startPeriod ? ' - ' + endPeriod : ''}</span>
-                                    </div>`;
-                            }
-                        }
-
                         card.innerHTML = `
                             <div class="card-content" data-item-id="${item._id}">
                                 <h3 class="item-col-name">${item.Name}</h3>
@@ -1037,7 +1003,6 @@
                                     ${imagesHtml}
                                 </div>
                                 ${borrowerBadge}
-                                ${appointmentBadge}
                             </div>
                             <div class="actions">
                                 ${isAvailableForBorrow && !item.BlockedNow ? 
@@ -1614,27 +1579,6 @@
             `;
         }
         
-        // Add appointment info panel if item has appointments
-        let appointmentInfoHtml = '';
-        if (item.appointments && Array.isArray(item.appointments) && item.appointments.length > 0) {
-            const upcomingAppointment = getUpcomingAppointment(item.appointments);
-            if (upcomingAppointment) {
-                const formattedDate = formatAppointmentDate(upcomingAppointment.date);
-                const startPeriod = formatAppointmentPeriod(upcomingAppointment.start_period);
-                const endPeriod = formatAppointmentPeriod(upcomingAppointment.end_period);
-                const timeDisplay = startPeriod + (endPeriod && endPeriod !== startPeriod ? ' - ' + endPeriod : '');
-                
-                appointmentInfoHtml = `
-                    <div class="appointment-info-panel">
-                        <h4>Geplanter Termin</h4>
-                        <p class="appointment-date">Datum: ${formattedDate}</p>
-                        <p class="appointment-time">Zeit: ${timeDisplay}</p>
-                        ${upcomingAppointment.notes ? `<p class="appointment-notes">Notizen: ${upcomingAppointment.notes}</p>` : ''}
-                    </div>
-                `;
-            }
-        }
-        
         // Build modal content HTML
         modalContent.innerHTML = `
             <h2>${item.Name}</h2>
@@ -1642,7 +1586,6 @@
                 <button type="button" class="bookmark-btn" id="modal-bookmark-btn" title="Merken">${(window.currentFavorites||new Set()).has(item._id) ? '★' : '☆'}</button>
             </div>
             ${borrowerInfoHtml}
-            ${appointmentInfoHtml}
             
             <div class="modal-image-container">
                 ${imagesHtml}
@@ -2804,66 +2747,6 @@
         }
     }
 
-    // Helper functions for appointment display
-    function formatAppointmentDate(dateString) {
-        if (!dateString) return '';
-        try {
-                       const date = new Date(dateString);
-            return date.toLocaleDateString('de-DE', {
-                day: '2-digit',
-                month: '2-digit',
-                year: 'numeric'
-            });
-        } catch (e) {
-            return dateString;
-        }
-    }
-
-    function formatAppointmentPeriod(period) {
-        if (!period) return '';
-        const periodMap = {
-            '1': '1. Stunde',
-            '2': '2. Stunde',
-            '3': '3. Stunde',
-            '4': '4. Stunde',
-            '5': '5. Stunde',
-            '6': '6. Stunde',
-            '7': '7. Stunde',
-            '8': '8. Stunde',
-            '9': '9. Stunde',
-            '10': '10. Stunde',
-            'pause1': '1. Pause',
-            'pause2': '2. Pause',
-            'mittagspause': 'Mittagspause'
-        };
-        return periodMap[period] || period;
-    }
-
-    function getUpcomingAppointment(appointments) {
-        if (!appointments || !Array.isArray(appointments) || appointments.length === 0) {
-            return null;
-        }
-        
-        const now = new Date();
-        const today = now.toDateString();
-        
-        // Filter appointments that are today or in the future
-        const futureAppointments = appointments.filter(apt => {
-            try {
-                const aptDate = new Date(apt.date);
-                return aptDate.toDateString() === today || aptDate >= now.setHours(0, 0, 0, 0);
-            } catch (e) {
-                return false;
-            }
-        });
-        
-        if (futureAppointments.length === 0) return null;
-        
-        // Sort by date and return the earliest
-        futureAppointments.sort((a, b) => new Date(a.date) - new Date(b.date));
-        return futureAppointments[0];
-    }
-
     function formatDateForInput(dateString) {
         const options = { year: 'numeric', month: '2-digit', day: '2-digit' };
         const date = new Date(dateString);
@@ -3947,16 +3830,6 @@
     .borrower-info-panel h4 { color: #856404; margin: 0 0 10px 0; font-size: 1.1rem; }
     .borrower-name, .borrow-time { margin: 5px 0; color: #856404; font-weight: 500; }
 
-    .appointment-info-panel {
-        background-color: #e1f5fe;
-        border: 1px solid #81d4fa;
-        border-radius: 5px;
-        padding: 15px;
-        margin-bottom: 20px;
-    }
-    .appointment-info-panel h4 { color: #0277bd; margin: 0 0 10px 0; font-size: 1.1rem; }
-    .appointment-date, .appointment-time, .appointment-user { margin: 5px 0; color: #0277bd; font-weight: 500; }
-
     /* Modal Details Styling (text formatting) */
     .modal-details { margin: 20px 0; }
     .detail-group { display: flex; margin-bottom: 10px; align-items: flex-start; }

Web/templates/maintenance.html

@@ -0,0 +1,28 @@
+{% extends "base.html" %}
+
+{% block title %}Wartungsarbeiten - Inventarsystem{% endblock %}
+
+{% block content %}
+<div class="container py-5">
+    <div class="row justify-content-center">
+        <div class="col-12 col-lg-8 col-xl-7">
+            <div class="card border-0 shadow-lg rounded-4 overflow-hidden">
+                <div class="card-header text-white" style="background: linear-gradient(135deg, #0f4c5c, #16697a);">
+                    <p class="text-uppercase small fw-semibold mb-1 opacity-75">Systemstatus</p>
+                    <h1 class="h3 mb-0 fw-bold">Wartungsarbeiten</h1>
+                </div>
+                <div class="card-body p-4 p-md-5 bg-white text-center">
+                    <div class="display-3 fw-bold text-warning mb-3">500</div>
+                    <p class="lead mb-2">Das System führt gerade Wartungsarbeiten durch.</p>
+                    <p class="text-muted mb-4">Bitte versuchen Sie es in wenigen Minuten erneut. Falls das Problem bestehen bleibt, informieren Sie bitte die Administration.</p>
+
+                    <div class="d-flex flex-column flex-sm-row justify-content-center gap-2">
+                        <a href="{{ url_for('login') }}" class="btn btn-primary btn-lg">Zum Login</a>
+                        <a href="javascript:history.back()" class="btn btn-outline-secondary btn-lg">Zurück</a>
+                    </div>
+                </div>
+            </div>
+        </div>
+    </div>
+</div>
+{% endblock %}

Web/templates/termin_client.html

@@ -44,7 +44,7 @@
                     <div class="card border-0 shadow-lg rounded-4 h-100">
                         <div class="card-body p-4 p-md-5 bg-white">
                             <h2 class="h4 fw-bold mb-4">Buchung absenden</h2>
-                            <form method="post" action="{{ url_for('terminplaner.client', appointment_id=appointment_id) }}" class="vstack gap-3">
+                            <form method="post" action="{{ url_for('terminplaner.client', appointment_id=appointment_id, tenant=tenant_id) }}" class="vstack gap-3">
                                 <div>
                                     <label for="start_day_time" class="form-label fw-semibold">Gewünschter Zeitpunkt</label>
                                     <input type="text" id="start_day_time" name="start_day_time" class="form-control form-control-lg" placeholder="2026-05-29 10:30" required>
@@ -56,7 +56,7 @@
                                 </div>
                                 <div class="d-flex flex-column flex-sm-row gap-2 pt-2">
                                     <button type="submit" class="btn btn-primary btn-lg">Termin buchen</button>
-                                    <a class="btn btn-outline-secondary btn-lg" href="{{ url_for('terminplaner.main') }}">Zur Übersicht</a>
+                                    <a class="btn btn-outline-secondary btn-lg" href="{{ url_for('terminplaner.main', tenant=tenant_id) }}">Zur Übersicht</a>
                                 </div>
                             </form>
                         </div>

Web/templates/termin_configure.html

@@ -24,10 +24,33 @@
                             </div>
                         </div>
 
-                        <div>
-                            <label for="time_frame" class="form-label fw-semibold">Zeitfenster</label>
-                            <textarea id="time_frame" name="time_frame" class="form-control" rows="5" placeholder="Beispiele:\nMontag 08:00-12:00\nDienstag 08:00-12:00" required></textarea>
-                            <div class="form-text">Jede Zeile kann ein eigenes Zeitfenster enthalten.</div>
+                        <div class="border rounded-4 p-3 p-md-4 bg-light-subtle">
+                            <div class="d-flex flex-column flex-md-row justify-content-between align-items-md-center gap-2 mb-2">
+                                <div>
+                                    <label class="form-label fw-semibold mb-0">Zeitfenster pro Tag</label>
+                                    <div class="form-text mb-0">Sobald Start- und Enddatum gesetzt sind, wird für jeden Tag automatisch ein eigener Eintrag erzeugt.</div>
+                                </div>
+                                <button type="button" class="btn btn-outline-primary btn-sm" id="build_time_frame">Tage aus Zeitraum erzeugen</button>
+                            </div>
+
+                            <div class="row g-3 mb-3">
+                                <div class="col-12 col-md-6 col-xl-4">
+                                    <label for="default_day_start" class="form-label fw-semibold">Standard-Startzeit</label>
+                                    <input type="time" id="default_day_start" class="form-control" value="08:00">
+                                </div>
+                                <div class="col-12 col-md-6 col-xl-4">
+                                    <label for="default_day_end" class="form-label fw-semibold">Standard-Endzeit</label>
+                                    <input type="time" id="default_day_end" class="form-control" value="12:00">
+                                </div>
+                            </div>
+
+                            <div id="time_frame_days" class="vstack gap-2"></div>
+
+                            <div class="mt-3">
+                                <label for="time_frame" class="form-label fw-semibold">Gespeichertes Zeitfenster</label>
+                                <textarea id="time_frame" name="time_frame" class="form-control font-monospace" rows="5" placeholder="Wird automatisch aus den Tagen erzeugt" required></textarea>
+                                <div class="form-text">Das Formular überträgt die erzeugten Tageszeilen an das Backend. Sie können die Liste hier bei Bedarf noch anpassen.</div>
+                            </div>
                         </div>
 
                         <div class="row g-3">
@@ -51,6 +74,12 @@
                             <textarea id="note" name="note" class="form-control" rows="4" placeholder="Optionaler Einführungstext für die Mail"></textarea>
                         </div>
 
+                        <div class="form-check">
+                            <input class="form-check-input" type="checkbox" id="add_to_calendar" name="add_to_calendar" {% if add_to_calendar %}checked{% endif %}>
+                            <label class="form-check-label fw-semibold" for="add_to_calendar">Kalendereintrag für den Nutzer erzeugen</label>
+                            <div class="form-text">Erzeugt zusätzlich eine .ics-Datei, die in gängige Kalender importiert werden kann.</div>
+                        </div>
+
                         <div class="d-flex flex-column flex-sm-row gap-2 pt-2">
                             <button type="submit" class="btn btn-primary btn-lg">Terminplan erzeugen</button>
                             <a class="btn btn-outline-secondary btn-lg" href="{{ url_for('terminplaner.main') }}">Zur Übersicht</a>
@@ -62,11 +91,168 @@
             {% if generated_link %}
             <div class="alert alert-success mt-4 shadow-sm rounded-4">
                 <div class="fw-bold mb-1">Buchungslink erstellt</div>
-                <div class="mb-2">Teilen Sie diesen Link mit den Teilnehmenden:</div>
+                <div class="mb-2">
+                    {% if email_service_enabled %}
+                        Teilen Sie diesen Link mit den Teilnehmenden oder versenden Sie ihn direkt per E-Mail.
+                    {% else %}
+                        Der E-Mail-Service ist deaktiviert. Teilen Sie diesen Link manuell mit den Teilnehmenden.
+                    {% endif %}
+                </div>
                 <a href="{{ generated_link }}" class="d-inline-block text-break">{{ generated_link }}</a>
+                {% if calendar_link %}
+                <div class="mt-3">
+                    <div class="fw-semibold mb-1">Kalendereintrag</div>
+                    <a href="{{ calendar_link }}" class="btn btn-outline-primary btn-sm">.ics herunterladen</a>
+                </div>
+                {% endif %}
             </div>
             {% endif %}
         </div>
     </div>
 </div>
+<script>
+(function () {
+    const startDateInput = document.getElementById('start_date');
+    const endDateInput = document.getElementById('end_date');
+    const buildButton = document.getElementById('build_time_frame');
+    const daysContainer = document.getElementById('time_frame_days');
+    const timeFrameTextarea = document.getElementById('time_frame');
+    const defaultStartInput = document.getElementById('default_day_start');
+    const defaultEndInput = document.getElementById('default_day_end');
+
+    if (!startDateInput || !endDateInput || !buildButton || !daysContainer || !timeFrameTextarea || !defaultStartInput || !defaultEndInput) {
+        return;
+    }
+
+    const weekdayFormatter = new Intl.DateTimeFormat('de-DE', {
+        weekday: 'long',
+        day: '2-digit',
+        month: '2-digit',
+        year: 'numeric',
+    });
+
+    function parseDate(value) {
+        if (!value) {
+            return null;
+        }
+
+        const parts = value.split('-').map(Number);
+        if (parts.length !== 3 || parts.some(Number.isNaN)) {
+            return null;
+        }
+
+        return new Date(parts[0], parts[1] - 1, parts[2]);
+    }
+
+    function formatDateForRow(date) {
+        return weekdayFormatter.format(date);
+    }
+
+    function formatDateForValue(date) {
+        const year = date.getFullYear();
+        const month = String(date.getMonth() + 1).padStart(2, '0');
+        const day = String(date.getDate()).padStart(2, '0');
+        return `${year}-${month}-${day}`;
+    }
+
+    function addDays(date, days) {
+        const copy = new Date(date);
+        copy.setDate(copy.getDate() + days);
+        return copy;
+    }
+
+    function syncTextarea() {
+        const rows = Array.from(daysContainer.querySelectorAll('[data-day-row]'));
+        const lines = rows.map(function (row) {
+            const dayValue = row.getAttribute('data-day-value') || '';
+            const startTime = row.querySelector('[data-time-start]')?.value || '';
+            const endTime = row.querySelector('[data-time-end]')?.value || '';
+            return `${dayValue} ${startTime}-${endTime}`.trim();
+        }).filter(Boolean);
+
+        timeFrameTextarea.value = lines.join('\n');
+    }
+
+    function renderRows() {
+        const startDate = parseDate(startDateInput.value);
+        const endDate = parseDate(endDateInput.value);
+
+        if (!startDate || !endDate) {
+            daysContainer.innerHTML = '<div class="text-muted small">Bitte Start- und Enddatum auswählen, damit die Tageszeilen erzeugt werden.</div>';
+            timeFrameTextarea.value = '';
+            endDateInput.setCustomValidity('');
+            return;
+        }
+
+        if (endDate < startDate) {
+            daysContainer.innerHTML = '<div class="text-danger small">Das Enddatum muss nach dem Startdatum liegen.</div>';
+            timeFrameTextarea.value = '';
+            endDateInput.setCustomValidity('Das Enddatum muss nach dem Startdatum liegen.');
+            return;
+        }
+
+        endDateInput.setCustomValidity('');
+
+        const existingValues = new Map();
+        Array.from(daysContainer.querySelectorAll('[data-day-row]')).forEach(function (row) {
+            const dayValue = row.getAttribute('data-day-value');
+            const startTime = row.querySelector('[data-time-start]')?.value || '';
+            const endTime = row.querySelector('[data-time-end]')?.value || '';
+            if (dayValue) {
+                existingValues.set(dayValue, { startTime, endTime });
+            }
+        });
+
+        const defaultStart = defaultStartInput.value || '08:00';
+        const defaultEnd = defaultEndInput.value || '12:00';
+        const rows = [];
+
+        for (let current = startDate; current <= endDate; current = addDays(current, 1)) {
+            const dayValue = formatDateForValue(current);
+            const preserved = existingValues.get(dayValue) || {};
+            const rowStart = preserved.startTime || defaultStart;
+            const rowEnd = preserved.endTime || defaultEnd;
+
+            rows.push(`
+                <div class="border rounded-3 bg-white p-3" data-day-row data-day-value="${dayValue}">
+                    <div class="row g-2 align-items-end">
+                        <div class="col-12 col-lg-5">
+                            <label class="form-label fw-semibold mb-1">${formatDateForRow(current)}</label>
+                            <div class="text-muted small">${dayValue}</div>
+                        </div>
+                        <div class="col-6 col-lg-3">
+                            <label class="form-label mb-1">Von</label>
+                            <input type="time" class="form-control" value="${rowStart}" data-time-start>
+                        </div>
+                        <div class="col-6 col-lg-3">
+                            <label class="form-label mb-1">Bis</label>
+                            <input type="time" class="form-control" value="${rowEnd}" data-time-end>
+                        </div>
+                    </div>
+                </div>
+            `);
+        }
+
+        daysContainer.innerHTML = rows.join('');
+        daysContainer.querySelectorAll('input[type="time"]').forEach(function (input) {
+            input.addEventListener('input', syncTextarea);
+            input.addEventListener('change', syncTextarea);
+        });
+
+        syncTextarea();
+    }
+
+    buildButton.addEventListener('click', renderRows);
+    startDateInput.addEventListener('input', renderRows);
+    startDateInput.addEventListener('change', renderRows);
+    endDateInput.addEventListener('input', renderRows);
+    endDateInput.addEventListener('change', renderRows);
+    defaultStartInput.addEventListener('change', syncTextarea);
+    defaultEndInput.addEventListener('change', syncTextarea);
+
+    if (startDateInput.value && endDateInput.value) {
+        renderRows();
+    }
+})();
+</script>
 {% endblock %}

Web/templates/terminplaner.html

@@ -14,8 +14,8 @@
                         <p class="lead mb-0" style="max-width: 60ch; opacity: .95;">Erstellen Sie neue Terminreihen, teilen Sie Buchungslinks und öffnen Sie den Kalender für bestehende Reservierungen.</p>
                     </div>
                     <div class="d-flex flex-wrap gap-2">
-                        <a class="btn btn-light btn-lg fw-semibold" href="{{ url_for('terminplaner.configure') }}">Neue Planung</a>
-                        <a class="btn btn-outline-light btn-lg fw-semibold" href="{{ url_for('terminplan') }}">Kalender öffnen</a>
+                        <a class="btn btn-light btn-lg fw-semibold" href="{{ url_for('terminplaner.configure', tenant=tenant_id) }}">Neue Planung</a>
+                        <a class="btn btn-outline-light btn-lg fw-semibold" href="{{ url_for('terminplan', tenant=tenant_id) }}">Kalender öffnen</a>
                     </div>
                 </div>
             </section>
@@ -27,7 +27,7 @@
                             <div class="display-6 mb-3">🗓️</div>
                             <h2 class="h4 fw-bold">Kalender</h2>
                             <p class="mb-4 text-muted">Sehen Sie vorhandene Termine, ihre Auslastung und die aktuellen Reservierungen im Kalender.</p>
-                            <a class="btn btn-primary w-100" href="{{ url_for('terminplan') }}">Zum Kalender</a>
+                            <a class="btn btn-primary w-100" href="{{ url_for('terminplan', tenant=tenant_id) }}">Zum Kalender</a>
                         </div>
                     </div>
                 </div>
@@ -37,7 +37,7 @@
                             <div class="display-6 mb-3">✍️</div>
                             <h2 class="h4 fw-bold">Neue Planung</h2>
                             <p class="mb-4 text-muted">Erstellen Sie einen neuen Terminplan und verschicken Sie den Buchungslink an Ihre Zielgruppe.</p>
-                            <a class="btn btn-outline-primary w-100" href="{{ url_for('terminplaner.configure') }}">Konfiguration öffnen</a>
+                            <a class="btn btn-outline-primary w-100" href="{{ url_for('terminplaner.configure', tenant=tenant_id) }}">Konfiguration öffnen</a>
                         </div>
                     </div>
                 </div>
@@ -58,6 +58,48 @@
                 <h2 class="h5 fw-bold mb-2">Angemeldet als {{ current_user }}</h2>
                 <p class="mb-0 text-muted">Sie können Termine anlegen, den Kalender prüfen und Buchungslinks verteilen.</p>
             </div>
+
+            <div class="mt-4 p-4 rounded-4 bg-white shadow-sm">
+                <div class="d-flex flex-column flex-md-row justify-content-between align-items-md-center gap-2 mb-3">
+                    <h2 class="h5 fw-bold mb-0">Kommende Termine</h2>
+                    <span class="text-muted small">Alle offenen Terminpläne dieses Nutzers</span>
+                </div>
+
+                {% if upcoming_events %}
+                <div class="vstack gap-3">
+                    {% for event in upcoming_events %}
+                    <div class="border rounded-3 p-3">
+                        <div class="d-flex flex-column flex-lg-row justify-content-between gap-3">
+                            <div>
+                                <div class="fw-semibold">{{ event.date_start }} bis {{ event.date_end }}</div>
+                                <div class="text-muted small">ID: {{ event.appointment_id }}</div>
+                                {% if event.time_span %}
+                                <div class="small mt-1">Zeitfenster: {{ event.time_span|join(' | ') }}</div>
+                                {% endif %}
+                                {% if event.note %}
+                                <div class="small mt-1 text-muted">Notiz: {{ event.note }}</div>
+                                {% endif %}
+                            </div>
+                            <div class="text-lg-end">
+                                <div class="small mb-2">Gebucht: <strong>{{ event.slots_booked }}</strong> / {{ event.slots_total }} | Frei: <strong>{{ event.slots_left }}</strong></div>
+                                <div class="d-flex flex-wrap gap-2 justify-content-lg-end">
+                                    <a class="btn btn-sm btn-primary" href="{{ event.link }}" target="_blank" rel="noopener">Client-Link öffnen</a>
+                                    {% if event.calendar_link %}
+                                    <a class="btn btn-sm btn-outline-primary" href="{{ event.calendar_link }}">.ics</a>
+                                    {% endif %}
+                                    <form method="post" action="{{ url_for('terminplaner.delete_appointment', appointment_id=event.appointment_id, tenant=tenant_id) }}" class="d-inline" onsubmit="return confirm('Diesen Terminplan wirklich löschen?');">
+                                        <button type="submit" class="btn btn-sm btn-outline-danger">Entfernen</button>
+                                    </form>
+                                </div>
+                            </div>
+                        </div>
+                    </div>
+                    {% endfor %}
+                </div>
+                {% else %}
+                <div class="text-muted">Keine kommenden Termine gefunden.</div>
+                {% endif %}
+            </div>
             {% endif %}
         </div>
     </div>

Web/templates/terminplaner_not_found.html

@@ -0,0 +1,28 @@
+{% extends "base.html" %}
+
+{% block title %}Termin nicht gefunden - Inventarsystem{% endblock %}
+
+{% block content %}
+<div class="container py-5">
+    <div class="row justify-content-center">
+        <div class="col-12 col-lg-8 col-xl-7">
+            <div class="card border-0 shadow-lg rounded-4 overflow-hidden">
+                <div class="card-header text-white" style="background: linear-gradient(135deg, #0f4c5c, #16697a);">
+                    <p class="text-uppercase small fw-semibold mb-1 opacity-75">Terminplaner</p>
+                    <h1 class="h3 mb-0 fw-bold">Termin nicht gefunden</h1>
+                </div>
+                <div class="card-body p-4 p-md-5 bg-white text-center">
+                    <div class="display-3 fw-bold text-danger mb-3">404</div>
+                    <p class="lead mb-2">Der angeforderte Termin existiert nicht mehr oder der Link ist ungültig.</p>
+                    <p class="text-muted mb-4">Bitte prüfen Sie den Link erneut oder öffnen Sie den Terminplaner von der Startseite aus.</p>
+
+                    <div class="d-flex flex-column flex-sm-row justify-content-center gap-2">
+                        <a href="{{ url_for('home') }}" class="btn btn-primary btn-lg">Zur Startseite</a>
+                        <a href="javascript:history.back()" class="btn btn-outline-secondary btn-lg">Zurück</a>
+                    </div>
+                </div>
+            </div>
+        </div>
+    </div>
+</div>
+{% endblock %}

Web/tenant.py

@@ -473,6 +473,20 @@ class TenantContext:
         if not has_request_context():
             return None
 
+        # Query parameters are useful for public links that must open a specific tenant
+        # even when the host/subdomain cannot be mapped reliably.
+        tenant_from_query = (
+            request.args.get('tenant', '').strip()
+            or request.args.get('tenant_id', '').strip()
+            or request.args.get('tenantId', '').strip()
+        )
+        if tenant_from_query:
+            matched_tenant = _find_registered_tenant_id(tenant_from_query) or tenant_from_query
+            self.tenant_id = matched_tenant
+            self.config = get_tenant_config(matched_tenant)
+            session['tenant_id'] = matched_tenant
+            return self._get_db_name(matched_tenant)
+
         # Priority 1: X-Tenant-ID header (for testing/internal APIs)
         tenant_from_header = request.headers.get('X-Tenant-ID', '').strip()
         if tenant_from_header:
@@ -531,6 +545,10 @@ class TenantContext:
                     potential_subdomain = parts[0]
                     if potential_subdomain not in ('www', 'api', 'admin', 'app', 'mail'):
                         matched_tenant = _find_registered_tenant_id(potential_subdomain)
+                        if not matched_tenant and potential_subdomain.startswith('school'):
+                            matched_tenant = _find_registered_tenant_id('schule' + potential_subdomain[len('school'):])
+                        elif not matched_tenant and potential_subdomain.startswith('schule'):
+                            matched_tenant = _find_registered_tenant_id('school' + potential_subdomain[len('schule'):])
                         if matched_tenant:
                             self.subdomain = potential_subdomain
                             self.tenant_id = matched_tenant

config.json

@@ -53,6 +53,9 @@
         "inventory": {
             "enabled": true
         },
+        "terminplan": {
+            "enabled": true
+        },
         "library": {
             "enabled": true
         },