fix: auto-scroll to typing indicator in chat

feat: add EditEventScreen with calendar and chat mode support
Add a unified event editor that works in two modes: - Calendar mode: Create/edit events directly via EventService API - Chat mode: Edit AI-proposed events before confirming them The chat mode allows users to modify proposed events (title, time, recurrence) and persists changes both locally and to the server. New components: DateTimePicker, ScrollableDropdown, useDropdownPosition New API: PUT /api/chat/messages/:messageId/proposal
2026-01-31 18:51:02 +01:00 · 2026-01-31 18:46:31 +01:00 · 2026-01-27 21:15:19 +01:00
36 changed files with 1698 additions and 284 deletions
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -76,6 +76,7 @@ src/
 │   │   ├── chat.tsx            # Chat screen (AI conversation)
 │   │   ├── calendar.tsx        # Calendar overview
 │   │   └── settings.tsx        # Settings screen (theme switcher, logout)
+│   ├── editEvent.tsx           # Event edit screen (dual-mode: calendar/chat)
 │   ├── event/
 │   │   └── [id].tsx            # Event detail screen (dynamic route)
 │   └── note/
@@ -93,8 +94,10 @@ src/
 │   ├── EventCardBase.tsx       # Event card layout with icons (uses CardBase)
 │   ├── EventCard.tsx           # Calendar event card (uses EventCardBase + edit/delete buttons)
 │   ├── EventConfirmDialog.tsx  # AI-proposed event confirmation modal (skeleton)
-│   ├── ProposedEventCard.tsx   # Chat event proposal (uses EventCardBase + confirm/reject buttons)
-│   └── DeleteEventModal.tsx    # Delete confirmation modal (uses ModalBase)
+│   ├── ProposedEventCard.tsx   # Chat event proposal (uses EventCardBase + confirm/reject/edit buttons)
+│   ├── DeleteEventModal.tsx    # Delete confirmation modal (uses ModalBase)
+│   ├── DateTimePicker.tsx      # Date and time picker components
+│   └── ScrollableDropdown.tsx  # Scrollable dropdown component
 ├── Themes.tsx                  # Theme definitions: THEMES object with defaultLight/defaultDark, Theme type
 ├── logging/
 │   ├── index.ts                # Re-exports
@@ -104,14 +107,16 @@ src/
 │   ├── ApiClient.ts            # HTTP client with X-User-Id header injection, request logging, handles empty responses (204)
 │   ├── AuthService.ts          # login(), register(), logout() - calls API and updates AuthStore
 │   ├── EventService.ts         # getAll(), getById(), getByDateRange(), create(), update(), delete(mode, occurrenceDate)
-│   └── ChatService.ts          # sendMessage(), confirmEvent(deleteMode, occurrenceDate), rejectEvent(), getConversations(), getConversation()
-└── stores/                     # Zustand state management
-    ├── index.ts                # Re-exports all stores
-    ├── AuthStore.ts            # user, isAuthenticated, isLoading, login(), logout(), loadStoredUser()
-    │                           # Uses expo-secure-store (native) / localStorage (web)
-    ├── ChatStore.ts            # messages[], isWaitingForResponse, addMessage(), addMessages(), updateMessage(), clearMessages(), setWaitingForResponse(), chatMessageToMessageData()
-    ├── EventsStore.ts          # events[], setEvents(), addEvent(), updateEvent(), deleteEvent()
-    └── ThemeStore.ts           # theme, setTheme() - reactive theme switching with Zustand
+│   └── ChatService.ts          # sendMessage(), confirmEvent(deleteMode, occurrenceDate), rejectEvent(), getConversations(), getConversation(), updateProposalEvent()
+├── stores/                     # Zustand state management
+│   ├── index.ts                # Re-exports all stores
+│   ├── AuthStore.ts            # user, isAuthenticated, isLoading, login(), logout(), loadStoredUser()
+│   │                           # Uses expo-secure-store (native) / localStorage (web)
+│   ├── ChatStore.ts            # messages[], isWaitingForResponse, addMessage(), addMessages(), updateMessage(), clearMessages(), setWaitingForResponse(), chatMessageToMessageData()
+│   ├── EventsStore.ts          # events[], setEvents(), addEvent(), updateEvent(), deleteEvent()
+│   └── ThemeStore.ts           # theme, setTheme() - reactive theme switching with Zustand
+└── hooks/
+    └── useDropdownPosition.ts  # Hook for positioning dropdowns relative to trigger element
 ```

 **Routing:** Tab-based navigation with Chat, Calendar, and Settings as main screens. Auth screens (login, register) outside tabs. Dynamic routes for event detail and note editing.
@@ -223,7 +228,7 @@ src/
 ├── app.ts                    # Entry point, DI setup, Express config
 ├── controllers/              # Request handlers + middleware (per architecture diagram)
 │   ├── AuthController.ts     # login(), register(), refresh(), logout()
-│   ├── ChatController.ts     # sendMessage(), confirmEvent(), rejectEvent(), getConversations(), getConversation()
+│   ├── ChatController.ts     # sendMessage(), confirmEvent(), rejectEvent(), getConversations(), getConversation(), updateProposalEvent()
 │   ├── EventController.ts    # create(), getById(), getAll(), getByDateRange(), update(), delete()
 │   ├── AuthMiddleware.ts     # authenticate() - X-User-Id header validation
 │   └── LoggingMiddleware.ts  # httpLogger - pino-http request logging
@@ -290,6 +295,7 @@ src/
 - `POST /api/chat/reject/:conversationId/:messageId` - Reject proposed event (protected)
 - `GET /api/chat/conversations` - Get all conversations (protected)
 - `GET /api/chat/conversations/:id` - Get messages of a conversation with cursor-based pagination (protected)
+- `PUT /api/chat/messages/:messageId/proposal` - Update proposal event data before confirming (protected)
 - `GET /health` - Health check
 - `POST /api/ai/test` - AI test endpoint (development only)

@@ -309,7 +315,9 @@ src/
 │                         # DAY_TO_GERMAN, DAY_TO_GERMAN_SHORT, MONTH_TO_GERMAN
 └── utils/
    ├── index.ts
-    └── dateHelpers.ts    # getDay() - get date for specific weekday relative to today
+    ├── dateHelpers.ts    # getDay() - get date for specific weekday relative to today
+    ├── formatters.ts     # formatDate(), formatTime(), formatDateTime(), formatDateWithWeekday() - German locale
+    └── rruleHelpers.ts   # parseRRule() - parse RRULE strings to extract freq, until, count, interval, byDay
 ```

 **Key Types:**
@@ -326,7 +334,7 @@ src/
 - `Conversation`: id, userId, createdAt?, updatedAt? (messages loaded separately via lazy loading)
 - `CreateUserDTO`: email, userName, password (for registration)
 - `LoginDTO`: identifier (email OR userName), password
- `CreateEventDTO`: Used for creating events AND for AI-proposed events
+- `CreateEventDTO`: Used for creating events AND for AI-proposed events, includes optional `exceptionDates` for proposals
 - `GetMessagesOptions`: Cursor-based pagination with `before?: string` and `limit?: number`
 - `ConversationSummary`: id, lastMessage?, createdAt? (for conversation list)
 - `UpdateMessageDTO`: proposalId?, respondedAction? (for marking individual proposals as confirmed/rejected)
@@ -463,11 +471,12 @@ NODE_ENV=development        # development = pretty logs, production = JSON
  - `utils/recurrenceExpander`: expandRecurringEvents() using rrule library for RRULE parsing
  - `ChatController`: getConversations(), getConversation() with cursor-based pagination support
  - `ChatService`: getConversations(), getConversation(), processMessage() uses real AI or test responses (via USE_TEST_RESPONSES), confirmEvent()/rejectEvent() update respondedAction and persist response messages
-  - `MongoChatRepository`: Full CRUD implemented (getConversationsByUser, createConversation, getMessages with cursor pagination, createMessage, updateMessage, updateProposalResponse)
-  - `ChatRepository` interface: updateMessage() and updateProposalResponse() for per-proposal respondedAction tracking
+  - `MongoChatRepository`: Full CRUD implemented (getConversationsByUser, createConversation, getMessages with cursor pagination, createMessage, updateMessage, updateProposalResponse, updateProposalEvent)
+  - `ChatRepository` interface: updateMessage(), updateProposalResponse(), updateProposalEvent() for per-proposal tracking
  - `GPTAdapter`: Full implementation with OpenAI GPT (gpt-4o-mini model), function calling for calendar operations, collects multiple proposals per response
  - `ai/utils/`: Provider-agnostic shared utilities (systemPrompt, toolDefinitions, toolExecutor, eventFormatter)
-  - `ai/utils/systemPrompt`: Includes RRULE documentation - AI knows to create separate events when times differ by day
+  - `ai/utils/systemPrompt`: Includes RRULE documentation - AI knows to create separate events when times differ by day, warns AI not to put RRULE in description field
+  - `ai/utils/toolDefinitions`: proposeUpdateEvent supports `isRecurring` and `recurrenceRule` parameters for adding UNTIL or modifying recurrence
  - `utils/recurrenceExpander`: Handles RRULE parsing, strips `RRULE:` prefix if present (AI may include it), filters out exceptionDates
  - `logging/`: Structured logging with pino, pino-http middleware, @Logged decorator
  - All repositories and GPTAdapter decorated with @Logged for automatic method logging
@@ -477,7 +486,11 @@ NODE_ENV=development        # development = pretty logs, production = JSON
  - `AuthService`: refreshToken()
  - JWT authentication (currently using simple X-User-Id header)

-**Shared:** Types, DTOs, constants (Day, Month with German translations), ExpandedEvent type, and date utilities defined and exported.
+**Shared:**
+- Types, DTOs, constants (Day, Month with German translations), ExpandedEvent type defined and exported
+- `rruleHelpers.ts`: `parseRRule()` parses RRULE strings using rrule library, returns `ParsedRRule` with freq, until, count, interval, byDay
+- `formatters.ts`: German date/time formatters (`formatDate`, `formatTime`, `formatDateTime`, `formatDateWithWeekday`) used by both client and server
+- rrule library added as dependency for RRULE parsing

 **Frontend:**
 - **Authentication fully implemented:**
@@ -520,12 +533,12 @@ NODE_ENV=development        # development = pretty logs, production = JSON
  - Auto-scroll to end on new messages and keyboard show
  - keyboardDismissMode="interactive" and keyboardShouldPersistTaps="handled"
 - `EventService`: getAll(), getById(), getByDateRange(), create(), update(), delete(mode, occurrenceDate) - fully implemented with recurring delete modes
- `ChatService`: sendMessage(), confirmEvent(deleteMode, occurrenceDate), rejectEvent(), getConversations(), getConversation() - fully implemented with cursor pagination and recurring delete support
+- `ChatService`: sendMessage(), confirmEvent(deleteMode, occurrenceDate), rejectEvent(), getConversations(), getConversation(), updateProposalEvent() - fully implemented with cursor pagination, recurring delete support, and proposal editing
 - `CardBase`: Reusable card component with header (title/subtitle), content area, and optional footer button - configurable padding, border, text size via props, ScrollView uses `nestedScrollEnabled` for Android
 - `ModalBase`: Reusable modal wrapper with backdrop (absolute-positioned behind card), uses CardBase internally - provides click-outside-to-close, Android back button support, and proper scrolling on Android
 - `EventCardBase`: Event card with date/time/recurring icons - uses CardBase for structure
 - `EventCard`: Uses EventCardBase + edit/delete buttons (TouchableOpacity with delayPressIn for scroll-friendly touch handling)
- `ProposedEventCard`: Uses EventCardBase + confirm/reject buttons for chat proposals (supports create/update/delete actions with deleteMode display)
+- `ProposedEventCard`: Uses EventCardBase + confirm/reject/edit buttons for chat proposals, displays green highlighted text for new changes ("Neue Ausnahme: [date]" for single delete, "Neues Ende: [date]" for UNTIL updates). Edit button allows modifying proposals before confirming.
 - `DeleteEventModal`: Delete confirmation modal using ModalBase - shows three options for recurring events (single/future/all), simple confirm for non-recurring
 - `EventOverlay` (in calendar.tsx): Day events overlay using ModalBase - shows EventCards for selected day
 - `Themes.tsx`: Theme definitions with THEMES object (defaultLight, defaultDark) including all color tokens (textPrimary, borderPrimary, eventIndicator, secondaryBg, shadowColor, etc.)
@@ -535,6 +548,11 @@ NODE_ENV=development        # development = pretty logs, production = JSON
 - `ChatBubble`: Reusable chat bubble component with Tailwind styling, used by ChatMessage and TypingIndicator
 - `TypingIndicator`: Animated typing indicator component showing `. → .. → ...` loop while waiting for AI response
 - Event Detail and Note screens exist as skeletons
+- `editEvent.tsx`: Dual-mode event editor screen
+  - **Calendar mode**: Edit existing events, create new events - calls EventService API
+  - **Chat mode**: Edit AI-proposed events before confirming - updates ChatStore locally and persists to server via ChatService.updateProposalEvent()
+  - Route params: `mode` ('calendar' | 'chat'), `id?`, `date?`, `eventData?` (JSON), `proposalContext?` (JSON with messageId, proposalId, conversationId)
+  - Supports recurring events with RRULE configuration (daily/weekly/monthly/yearly)

 ## Building

--- a/apps/client/package.json
+++ b/apps/client/package.json
@@ -14,6 +14,7 @@
  "dependencies": {
    "@calchat/shared": "*",
    "@expo/vector-icons": "^15.0.3",
+    "@react-native-community/datetimepicker": "8.4.4",
    "@react-navigation/bottom-tabs": "^7.4.0",
    "@react-navigation/elements": "^2.6.3",
    "@react-navigation/native": "^7.1.8",
@@ -43,6 +44,7 @@
    "react-native-screens": "~4.16.0",
    "react-native-web": "~0.21.0",
    "react-native-worklets": "0.5.1",
+    "rrule": "^2.8.1",
    "zustand": "^5.0.9"
  },
  "devDependencies": {
--- a/apps/client/src/Themes.tsx
+++ b/apps/client/src/Themes.tsx
@@ -46,8 +46,8 @@ export const THEMES = {
    messageBorderBg: "#3A3430",
    placeholderBg: "#4A4440",
    calenderBg: "#3D2A1A",
-    confirmButton: "#22c55e",
-    rejectButton: "#ef4444",
+    confirmButton: "#136e34",
+    rejectButton: "#bd1010",
    disabledButton: "#555",
    buttonText: "#FFFFFF",
    textPrimary: "#FFFFFF",
--- a/apps/client/src/app/(tabs)/calendar.tsx
+++ b/apps/client/src/app/(tabs)/calendar.tsx
@@ -1,4 +1,4 @@
-import { Animated, Modal, Pressable, Text, View } from "react-native";
+import { Pressable, Text, View } from "react-native";
 import {
  DAYS,
  MONTHS,
@@ -10,20 +10,20 @@ import Header from "../../components/Header";
 import { EventCard } from "../../components/EventCard";
 import { DeleteEventModal } from "../../components/DeleteEventModal";
 import { ModalBase } from "../../components/ModalBase";
+import { ScrollableDropdown } from "../../components/ScrollableDropdown";
 import React, {
  useCallback,
  useEffect,
  useMemo,
-  useRef,
  useState,
 } from "react";
-import { useFocusEffect } from "expo-router";
+import { router, useFocusEffect } from "expo-router";
 import { Ionicons } from "@expo/vector-icons";
 import { useThemeStore } from "../../stores/ThemeStore";
 import BaseBackground from "../../components/BaseBackground";
-import { FlashList } from "@shopify/flash-list";
 import { EventService } from "../../services";
 import { useEventsStore } from "../../stores";
+import { useDropdownPosition } from "../../hooks/useDropdownPosition";

 // MonthSelector types and helpers
 type MonthItem = {
@@ -74,6 +74,7 @@ const Calendar = () => {
  const [monthIndex, setMonthIndex] = useState(new Date().getMonth());
  const [currentYear, setCurrentYear] = useState(new Date().getFullYear());
  const [selectedDate, setSelectedDate] = useState<Date | null>(null);
+  const [overlayVisible, setOverlayVisible] = useState(false);

  // State for delete modal
  const [deleteModalVisible, setDeleteModalVisible] = useState(false);
@@ -114,20 +115,33 @@ const Calendar = () => {
  // Load events when tab gains focus or month/year changes
  // NOTE: Wrapper needed because loadEvents is async (returns Promise)
  // and useFocusEffect expects a sync function (optionally returning cleanup)
+  // Also re-open overlay if selectedDate exists (for back navigation from editEvent)
  useFocusEffect(
    useCallback(() => {
      loadEvents();
-    }, [loadEvents]),
+      if (selectedDate) {
+        setOverlayVisible(true);
+      }
+    }, [loadEvents, selectedDate]),
  );

  // Group events by date (YYYY-MM-DD format)
+  // Multi-day events are added to all days they span
  const eventsByDate = useMemo(() => {
    const map = new Map<string, ExpandedEvent[]>();
    events.forEach((e) => {
-      const date = new Date(e.occurrenceStart);
-      const key = getDateKey(date);
-      if (!map.has(key)) map.set(key, []);
-      map.get(key)!.push(e);
+      const start = new Date(e.occurrenceStart);
+      const end = new Date(e.occurrenceEnd);
+
+      // Iterate through each day the event spans
+      const current = new Date(start);
+      current.setHours(0, 0, 0, 0);
+      while (current <= end) {
+        const key = getDateKey(current);
+        if (!map.has(key)) map.set(key, []);
+        map.get(key)!.push(e);
+        current.setDate(current.getDate() + 1);
+      }
    });
    return map;
  }, [events]);
@@ -147,19 +161,32 @@ const Calendar = () => {
    });
  };

-  const handleDayPress = (date: Date, hasEvents: boolean) => {
-    if (hasEvents) {
-      setSelectedDate(date);
-    }
+  const handleDayPress = (date: Date) => {
+    setSelectedDate(date);
+    setOverlayVisible(true);
  };

  const handleCloseOverlay = () => {
    setSelectedDate(null);
+    setOverlayVisible(false);
  };

-  const handleEditEvent = (event: ExpandedEvent) => {
-    console.log("Edit event:", event.id);
-    // TODO: Navigate to event edit screen
+  const handleCreateEvent = () => {
+    setOverlayVisible(false);
+    router.push({
+      pathname: "/editEvent",
+      params: { date: selectedDate?.toISOString() },
+    });
+  };
+
+  const handleEditEvent = (event?: ExpandedEvent) => {
+    router.push({
+      pathname: "/editEvent",
+      params: {
+        mode: "calendar",
+        id: event?.id,
+      },
+    });
  };

  const handleDeleteEvent = (event: ExpandedEvent) => {
@@ -222,12 +249,13 @@ const Calendar = () => {
        onDayPress={handleDayPress}
      />
      <EventOverlay
-        visible={selectedDate !== null && !deleteModalVisible}
+        visible={overlayVisible && !deleteModalVisible}
        date={selectedDate}
        events={selectedDateEvents}
        onClose={handleCloseOverlay}
        onEditEvent={handleEditEvent}
        onDeleteEvent={handleDeleteEvent}
+        onCreateEvent={handleCreateEvent}
      />
      <DeleteEventModal
        visible={deleteModalVisible}
@@ -245,8 +273,9 @@ type EventOverlayProps = {
  date: Date | null;
  events: ExpandedEvent[];
  onClose: () => void;
-  onEditEvent: (event: ExpandedEvent) => void;
+  onEditEvent: (event?: ExpandedEvent) => void;
  onDeleteEvent: (event: ExpandedEvent) => void;
+  onCreateEvent: () => void;
 };

 const EventOverlay = ({
@@ -256,7 +285,10 @@ const EventOverlay = ({
  onClose,
  onEditEvent,
  onDeleteEvent,
+  onCreateEvent,
 }: EventOverlayProps) => {
+  const { theme } = useThemeStore();
+
  if (!date) return null;

  const dateString = date.toLocaleDateString("de-DE", {
@@ -268,12 +300,26 @@ const EventOverlay = ({

  const subtitle = `${events.length} ${events.length === 1 ? "Termin" : "Termine"}`;

+  const addEventAttachment = (
+    <Pressable
+      className="flex flex-row justify-center items-center py-3"
+      style={{ backgroundColor: theme.confirmButton }}
+      onPress={onCreateEvent}
+    >
+      <Ionicons name="add-outline" size={24} color={theme.buttonText} />
+      <Text style={{ color: theme.buttonText }} className="font-semibold ml-1">
+        Neuen Termin erstellen
+      </Text>
+    </Pressable>
+  );
+
  return (
    <ModalBase
      visible={visible}
      onClose={onClose}
      title={dateString}
      subtitle={subtitle}
+      attachment={addEventAttachment}
      footer={{ label: "Schliessen", onPress: onClose }}
      scrollable={true}
      maxContentHeight={400}
@@ -299,6 +345,8 @@ type MonthSelectorProps = {
  onSelectMonth: (year: number, monthIndex: number) => void;
 };

+const INITIAL_RANGE = 12; // 12 months before and after current
+
 const MonthSelector = ({
  modalVisible,
  onClose,
@@ -307,131 +355,98 @@ const MonthSelector = ({
  currentMonthIndex,
  onSelectMonth,
 }: MonthSelectorProps) => {
-  const { theme } = useThemeStore();
-  const heightAnim = useRef(new Animated.Value(0)).current;
-  const listRef = useRef<React.ComponentRef<typeof FlashList<MonthItem>>>(null);
-  const INITIAL_RANGE = 12; // 12 months before and after current
-
  const [monthSelectorData, setMonthSelectorData] = useState<MonthItem[]>([]);

-  const appendMonths = (direction: "start" | "end", count: number) => {
-    setMonthSelectorData((prevData) => {
-      if (prevData.length === 0) return prevData;
+  const appendMonths = useCallback(
+    (direction: "start" | "end", count: number) => {
+      setMonthSelectorData((prevData) => {
+        if (prevData.length === 0) return prevData;

-      const newMonths: MonthItem[] = [];
-      const referenceMonth =
-        direction === "start" ? prevData[0] : prevData[prevData.length - 1];
+        const newMonths: MonthItem[] = [];
+        const referenceMonth =
+          direction === "start" ? prevData[0] : prevData[prevData.length - 1];

-      for (let i = 1; i <= count; i++) {
-        const offset = direction === "start" ? -i : i;
-        let year = referenceMonth.year;
-        let month = referenceMonth.monthIndex + offset;
+        for (let i = 1; i <= count; i++) {
+          const offset = direction === "start" ? -i : i;
+          let year = referenceMonth.year;
+          let month = referenceMonth.monthIndex + offset;

-        while (month < 0) {
-          month += 12;
-          year--;
-        }
-        while (month > 11) {
-          month -= 12;
-          year++;
+          while (month < 0) {
+            month += 12;
+            year--;
+          }
+          while (month > 11) {
+            month -= 12;
+            year++;
+          }
+
+          const newMonth: MonthItem = {
+            id: `${year}-${String(month + 1).padStart(2, "0")}`,
+            year,
+            monthIndex: month,
+            label: `${MONTHS[month]} ${year}`,
+          };
+
+          if (direction === "start") {
+            newMonths.unshift(newMonth);
+          } else {
+            newMonths.push(newMonth);
+          }
        }

-        const newMonth: MonthItem = {
-          id: `${year}-${String(month + 1).padStart(2, "0")}`,
-          year,
-          monthIndex: month,
-          label: `${MONTHS[month]} ${year}`,
-        };
-
-        if (direction === "start") {
-          newMonths.unshift(newMonth);
-        } else {
-          newMonths.push(newMonth);
-        }
-      }
-
-      return direction === "start"
-        ? [...newMonths, ...prevData]
-        : [...prevData, ...newMonths];
-    });
-  };
+        return direction === "start"
+          ? [...newMonths, ...prevData]
+          : [...prevData, ...newMonths];
+      });
+    },
+    [],
+  );

+  // Generate fresh data when modal opens, clear when closes
  useEffect(() => {
    if (modalVisible) {
-      // Generate fresh data centered on current month
      setMonthSelectorData(
        generateMonths(currentYear, currentMonthIndex, INITIAL_RANGE),
      );
-      Animated.timing(heightAnim, {
-        toValue: 200,
-        duration: 200,
-        useNativeDriver: false,
-      }).start();
    } else {
-      heightAnim.setValue(0);
-      // Clear data when closing
      setMonthSelectorData([]);
    }
-  }, [modalVisible, heightAnim, currentYear, currentMonthIndex]);
+  }, [modalVisible, currentYear, currentMonthIndex]);

-  const renderItem = ({ item }: { item: MonthItem }) => (
-    <Pressable
-      onPress={() => {
-        onSelectMonth(item.year, item.monthIndex);
-        onClose();
-      }}
-    >
-      <View
-        className="w-full flex justify-center items-center py-2"
-        style={{
-          backgroundColor:
-            item.monthIndex % 2 === 0 ? theme.primeBg : theme.secondaryBg,
-        }}
-      >
-        <Text className="text-xl" style={{ color: theme.primeFg }}>
-          {item.label}
-        </Text>
-      </View>
-    </Pressable>
+  const handleSelect = useCallback(
+    (item: MonthItem) => {
+      onSelectMonth(item.year, item.monthIndex);
+      onClose();
+    },
+    [onSelectMonth, onClose],
  );

  return (
-    <Modal
+    <ScrollableDropdown
      visible={modalVisible}
-      transparent={true}
-      animationType="none"
-      onRequestClose={onClose}
-    >
-      <Pressable className="flex-1 rounded-lg" onPress={onClose}>
-        <Animated.View
-          className="absolute overflow-hidden"
+      onClose={onClose}
+      position={position}
+      data={monthSelectorData}
+      keyExtractor={(item) => item.id}
+      renderItem={(item, theme) => (
+        <View
+          className="w-full flex justify-center items-center py-2"
          style={{
-            top: position.top,
-            left: position.left,
-            width: position.width,
-            height: heightAnim,
-            backgroundColor: theme.primeBg,
-            borderWidth: 2,
-            borderColor: theme.borderPrimary,
-            borderRadius: 8,
+            backgroundColor:
+              item.monthIndex % 2 === 0 ? theme.primeBg : theme.secondaryBg,
          }}
        >
-          <FlashList
-            className="w-full"
-            style={{ borderRadius: 8 }}
-            ref={listRef}
-            keyExtractor={(item) => item.id}
-            data={monthSelectorData}
-            initialScrollIndex={INITIAL_RANGE}
-            onEndReachedThreshold={0.5}
-            onEndReached={() => appendMonths("end", 12)}
-            onStartReachedThreshold={0.5}
-            onStartReached={() => appendMonths("start", 12)}
-            renderItem={renderItem}
-          />
-        </Animated.View>
-      </Pressable>
-    </Modal>
+          <Text className="text-xl" style={{ color: theme.primeFg }}>
+            {item.label}
+          </Text>
+        </View>
+      )}
+      onSelect={handleSelect}
+      height={200}
+      initialScrollIndex={INITIAL_RANGE}
+      onEndReached={() => appendMonths("end", 12)}
+      onStartReached={() => appendMonths("start", 12)}
+    />
  );
 };

@@ -445,29 +460,16 @@ type CalendarHeaderProps = {

 const CalendarHeader = (props: CalendarHeaderProps) => {
  const { theme } = useThemeStore();
-  const [modalVisible, setModalVisible] = useState(false);
-  const [dropdownPosition, setDropdownPosition] = useState({
-    top: 0,
-    left: 0,
-    width: 0,
-  });
-  const containerRef = useRef<View>(null);
+  const dropdown = useDropdownPosition();

  const prevMonth = () => props.changeMonth(-1);
  const nextMonth = () => props.changeMonth(1);

-  const measureAndOpen = () => {
-    containerRef.current?.measureInWindow((x, y, width, height) => {
-      setDropdownPosition({ top: y + height, left: x, width });
-      setModalVisible(true);
-    });
-  };
-
  return (
    <Header className="flex flex-row items-center justify-between">
      <ChangeMonthButton onPress={prevMonth} icon="chevron-back" />
      <View
-        ref={containerRef}
+        ref={dropdown.ref}
        className="relative flex flex-row items-center justify-around"
      >
        <Text className="text-4xl px-1" style={{ color: theme.textPrimary }}>
@@ -486,15 +488,15 @@ const CalendarHeader = (props: CalendarHeaderProps) => {
            // Android shadow
            elevation: 6,
          }}
-          onPress={measureAndOpen}
+          onPress={dropdown.open}
        >
          <Ionicons name="chevron-down" size={28} color={theme.primeFg} />
        </Pressable>
      </View>
      <MonthSelector
-        modalVisible={modalVisible}
-        onClose={() => setModalVisible(false)}
-        position={dropdownPosition}
+        modalVisible={dropdown.visible}
+        onClose={dropdown.close}
+        position={dropdown.position}
        currentYear={props.currentYear}
        currentMonthIndex={props.monthIndex}
        onSelectMonth={(year, month) => {
@@ -561,7 +563,7 @@ type CalendarGridProps = {
  month: Month;
  year: number;
  eventsByDate: Map<string, ExpandedEvent[]>;
-  onDayPress: (date: Date, hasEvents: boolean) => void;
+  onDayPress: (date: Date) => void;
 };

 const CalendarGrid = (props: CalendarGridProps) => {
@@ -602,7 +604,7 @@ const CalendarGrid = (props: CalendarGridProps) => {
                date={date}
                month={props.month}
                hasEvents={hasEvents}
-                onPress={() => props.onDayPress(date, hasEvents)}
+                onPress={() => props.onDayPress(date)}
              />
            );
          })}
--- a/apps/client/src/app/(tabs)/chat.tsx
+++ b/apps/client/src/app/(tabs)/chat.tsx
@@ -9,7 +9,7 @@ import {
 } from "react-native";
 import { useThemeStore } from "../../stores/ThemeStore";
 import React, { useState, useRef, useEffect, useCallback } from "react";
-import { useFocusEffect } from "expo-router";
+import { useFocusEffect, router } from "expo-router";
 import Header from "../../components/Header";
 import BaseBackground from "../../components/BaseBackground";
 import { FlashList } from "@shopify/flash-list";
@@ -38,6 +38,7 @@ type ChatMessageProps = {
  proposedChanges?: ProposedEventChange[];
  onConfirm?: (proposalId: string, proposal: ProposedEventChange) => void;
  onReject?: (proposalId: string) => void;
+  onEdit?: (proposalId: string, proposal: ProposedEventChange) => void;
 };

 type ChatInputProps = {
@@ -62,6 +63,7 @@ const Chat = () => {
  const [currentConversationId, setCurrentConversationId] = useState<
    string | undefined
  >();
+  const [hasLoadedMessages, setHasLoadedMessages] = useState(false);

  useEffect(() => {
    const keyboardDidShow = Keyboard.addListener(
@@ -71,10 +73,11 @@ const Chat = () => {
    return () => keyboardDidShow.remove();
  }, []);

-  // Load existing messages from database once authenticated and screen is focused
+  // Load existing messages from database only once (on initial mount)
+  // Skip on subsequent focus events to preserve local edits (e.g., edited proposals)
  useFocusEffect(
    useCallback(() => {
-      if (isAuthLoading || !isAuthenticated) return;
+      if (isAuthLoading || !isAuthenticated || hasLoadedMessages) return;

      const fetchMessages = async () => {
        try {
@@ -91,10 +94,12 @@ const Chat = () => {
          }
        } catch (error) {
          console.error("Failed to load messages:", error);
+        } finally {
+          setHasLoadedMessages(true);
        }
      };
      fetchMessages();
-    }, [isAuthLoading, isAuthenticated]),
+    }, [isAuthLoading, isAuthenticated, hasLoadedMessages]),
  );

  const scrollToEnd = () => {
@@ -159,6 +164,22 @@ const Chat = () => {
    }
  };

+  const handleEditProposal = (
+    messageId: string,
+    conversationId: string,
+    proposalId: string,
+    proposal: ProposedEventChange,
+  ) => {
+    router.push({
+      pathname: "/editEvent",
+      params: {
+        mode: "chat",
+        eventData: JSON.stringify(proposal.event),
+        proposalContext: JSON.stringify({ messageId, proposalId, conversationId }),
+      },
+    });
+  };
+
  const handleSend = async (text: string) => {
    // Show user message immediately
    const userMessage: MessageData = {
@@ -173,6 +194,7 @@ const Chat = () => {
    // Show typing indicator after delay
    typingTimeoutRef.current = setTimeout(() => {
      setWaitingForResponse(true);
+      scrollToEnd();
    }, TYPING_INDICATOR_DELAY_MS);

    try {
@@ -238,6 +260,14 @@ const Chat = () => {
                  proposalId,
                )
              }
+              onEdit={(proposalId, proposal) =>
+                handleEditProposal(
+                  item.id,
+                  item.conversationId!,
+                  proposalId,
+                  proposal,
+                )
+              }
            />
          )}
          keyExtractor={(item) => item.id}
@@ -334,6 +364,7 @@ const ChatMessage = ({
  proposedChanges,
  onConfirm,
  onReject,
+  onEdit,
 }: ChatMessageProps) => {
  const { theme } = useThemeStore();
  const [currentIndex, setCurrentIndex] = useState(0);
@@ -361,7 +392,7 @@ const ChatMessage = ({
        {content}
      </Text>

-      {hasProposals && currentProposal && onConfirm && onReject && (
+      {hasProposals && currentProposal && onConfirm && onReject && onEdit && (
        <View>
          {/* Event card with optional navigation arrows */}
          <View className="flex-row items-center">
@@ -381,8 +412,9 @@ const ChatMessage = ({
            <View className="flex-1">
              <ProposedEventCard
                proposedChange={currentProposal}
-                onConfirm={() => onConfirm(currentProposal.id, currentProposal)}
+                onConfirm={(proposal) => onConfirm(proposal.id, proposal)}
                onReject={() => onReject(currentProposal.id)}
+                onEdit={(proposal) => onEdit(proposal.id, proposal)}
              />
            </View>

--- a/apps/client/src/app/(tabs)/settings.tsx
+++ b/apps/client/src/app/(tabs)/settings.tsx
@@ -5,7 +5,7 @@ import { useThemeStore } from "../../stores/ThemeStore";
 import { AuthService } from "../../services/AuthService";
 import { router } from "expo-router";
 import { Ionicons } from "@expo/vector-icons";
-import Header from "../../components/Header";
+import { SimpleHeader } from "../../components/Header";
 import { THEMES } from "../../Themes";

 const handleLogout = async () => {
@@ -18,11 +18,7 @@ const Settings = () => {

  return (
    <BaseBackground>
-      <Header>
-        <View className="h-full flex justify-center">
-          <Text className="text-center text-3xl font-bold">Settings</Text>
-        </View>
-      </Header>
+      <SimpleHeader text="Settings" />
      <View className="flex items-center mt-4">
        <BaseButton onPress={handleLogout} solid={true}>
          <Ionicons name="log-out-outline" size={24} color={theme.primeFg} />{" "}
--- a/apps/client/src/app/_layout.tsx
+++ b/apps/client/src/app/_layout.tsx
@@ -7,8 +7,9 @@ export default function RootLayout() {
      <Stack.Screen name="(tabs)" />
      <Stack.Screen name="login" />
      <Stack.Screen name="register" />
-      <Stack.Screen name="event/[id]" />
-      <Stack.Screen name="note/[id]" />
+      <Stack.Screen name="editEvent" />
+      {/* <Stack.Screen name="event/[id]" /> */}
+      {/* <Stack.Screen name="note/[id]" /> */}
    </Stack>
  );
 }
--- a/apps/client/src/app/editEvent.tsx
+++ b/apps/client/src/app/editEvent.tsx
@@ -0,0 +1,597 @@
+import {
+  View,
+  Text,
+  TextInput,
+  Pressable,
+  ActivityIndicator,
+} from "react-native";
+import { Frequency, rrulestr } from "rrule";
+import BaseBackground from "../components/BaseBackground";
+import { useThemeStore } from "../stores/ThemeStore";
+import { useCallback, useEffect, useState } from "react";
+import { router, useLocalSearchParams } from "expo-router";
+import Header, { HeaderButton } from "../components/Header";
+import {
+  DatePickerButton,
+  TimePickerButton,
+} from "../components/DateTimePicker";
+import { Ionicons } from "@expo/vector-icons";
+import { ScrollableDropdown } from "../components/ScrollableDropdown";
+import { useDropdownPosition } from "../hooks/useDropdownPosition";
+import { EventService, ChatService } from "../services";
+import { buildRRule, CreateEventDTO } from "@calchat/shared";
+import { useChatStore } from "../stores";
+
+// Direct store access for getting current state in callbacks
+const getChatStoreState = () => useChatStore.getState();
+
+type EditEventTextFieldProps = {
+  titel: string;
+  text?: string;
+  focused?: boolean;
+  className?: string;
+  multiline?: boolean;
+  onValueChange?: (text: string) => void;
+};
+
+const EditEventTextField = (props: EditEventTextFieldProps) => {
+  const { theme } = useThemeStore();
+  const [focused, setFocused] = useState(props.focused ?? false);
+
+  return (
+    <View className={props.className}>
+      <Text className="text-xl" style={{ color: theme.textPrimary }}>
+        {props.titel}
+      </Text>
+      <TextInput
+        onChangeText={props.onValueChange}
+        value={props.text}
+        multiline={props.multiline}
+        className="flex-1 border border-solid rounded-2xl px-3 py-2 w-full h-11/12"
+        style={{
+          backgroundColor: theme.messageBorderBg,
+          color: theme.textPrimary,
+          textAlignVertical: "top",
+          borderColor: focused ? theme.chatBot : theme.borderPrimary,
+        }}
+        onFocus={() => setFocused(true)}
+        onBlur={() => setFocused(false)}
+      />
+    </View>
+  );
+};
+
+type PickerRowProps = {
+  title: string;
+  showLabels?: boolean;
+  dateValue: Date;
+  onDateChange: (date: Date) => void;
+  onTimeChange: (date: Date) => void;
+};
+
+const PickerRow = ({
+  showLabels,
+  dateValue,
+  title,
+  onDateChange,
+  onTimeChange,
+}: PickerRowProps) => {
+  const { theme } = useThemeStore();
+  return (
+    <View className="flex flex-row w-11/12 mt-4 items-end justify-between gap-x-2">
+      <Text className="text-xl pb-2" style={{ color: theme.textPrimary }}>
+        {title}
+      </Text>
+      <View className="flex flex-row w-10/12 gap-x-2">
+        <DatePickerButton
+          className="flex-1"
+          label={showLabels ? "Datum" : undefined}
+          value={dateValue}
+          onChange={onDateChange}
+        />
+        <TimePickerButton
+          className="flex-1"
+          label={showLabels ? "Uhrzeit" : undefined}
+          value={dateValue}
+          onChange={onTimeChange}
+        />
+      </View>
+    </View>
+  );
+};
+
+type RepeatType = "Tag" | "Woche" | "Monat" | "Jahr";
+
+const REPEAT_TYPE_LABELS: Record<RepeatType, string> = {
+  Tag: "Tage",
+  Woche: "Wochen",
+  Monat: "Monate",
+  Jahr: "Jahre",
+};
+
+type RepeatPressableProps = {
+  focused: boolean;
+  repeatType: RepeatType;
+  setRepeatType: (repeatType: RepeatType) => void;
+};
+
+const RepeatPressable = ({
+  focused,
+  repeatType,
+  setRepeatType,
+}: RepeatPressableProps) => {
+  const { theme } = useThemeStore();
+  return (
+    <Pressable
+      className="px-4 py-2 rounded-lg border"
+      style={{
+        backgroundColor: focused ? theme.chatBot : theme.secondaryBg,
+        borderColor: theme.borderPrimary,
+      }}
+      onPress={() => setRepeatType(repeatType)}
+    >
+      <Text style={{ color: focused ? theme.buttonText : theme.textPrimary }}>
+        {repeatType}
+      </Text>
+    </Pressable>
+  );
+};
+
+type RepeatSelectorProps = {
+  repeatCount: number;
+  onRepeatCountChange: (count: number) => void;
+  repeatType: RepeatType;
+  onRepeatTypeChange: (type: RepeatType) => void;
+};
+
+// Static data for repeat count dropdown (1-120)
+const REPEAT_COUNT_DATA = Array.from({ length: 120 }, (_, i) => i + 1);
+
+const RepeatSelector = ({
+  repeatCount,
+  onRepeatCountChange,
+  repeatType,
+  onRepeatTypeChange,
+}: RepeatSelectorProps) => {
+  const { theme } = useThemeStore();
+  const dropdown = useDropdownPosition(2);
+
+  const handleSelectCount = useCallback(
+    (count: number) => {
+      onRepeatCountChange(count);
+      dropdown.close();
+    },
+    [onRepeatCountChange, dropdown],
+  );
+
+  const typeLabel = REPEAT_TYPE_LABELS[repeatType];
+
+  return (
+    <View className="mt-4">
+      {/* Repeat Type Selection */}
+      <View className="flex flex-row gap-2 mb-3">
+        <RepeatPressable
+          repeatType="Tag"
+          setRepeatType={onRepeatTypeChange}
+          focused={repeatType === "Tag"}
+        />
+        <RepeatPressable
+          repeatType="Woche"
+          setRepeatType={onRepeatTypeChange}
+          focused={repeatType === "Woche"}
+        />
+        <RepeatPressable
+          repeatType="Monat"
+          setRepeatType={onRepeatTypeChange}
+          focused={repeatType === "Monat"}
+        />
+        <RepeatPressable
+          repeatType="Jahr"
+          setRepeatType={onRepeatTypeChange}
+          focused={repeatType === "Jahr"}
+        />
+      </View>
+
+      {/* Repeat Count Selection */}
+      <View className="flex flex-row items-center">
+        <Text className="text-lg" style={{ color: theme.textPrimary }}>
+          Alle{" "}
+        </Text>
+        <Pressable
+          ref={dropdown.ref}
+          className="px-4 py-2 rounded-lg border"
+          style={{
+            backgroundColor: theme.secondaryBg,
+            borderColor: theme.borderPrimary,
+          }}
+          onPress={dropdown.open}
+        >
+          <Text className="text-lg" style={{ color: theme.textPrimary }}>
+            {repeatCount}
+          </Text>
+        </Pressable>
+        <Text className="text-lg" style={{ color: theme.textPrimary }}>
+          {" "}
+          {typeLabel}
+        </Text>
+      </View>
+
+      {/* Count Dropdown */}
+      <ScrollableDropdown
+        visible={dropdown.visible}
+        onClose={dropdown.close}
+        position={{
+          bottom: 12,
+          left: 10,
+          width: 100,
+        }}
+        data={REPEAT_COUNT_DATA}
+        keyExtractor={(n) => String(n)}
+        renderItem={(n, theme) => (
+          <View
+            className="w-full flex justify-center items-center py-2"
+            style={{
+              backgroundColor: n % 2 === 0 ? theme.primeBg : theme.secondaryBg,
+            }}
+          >
+            <Text className="text-xl" style={{ color: theme.textPrimary }}>
+              {n}
+            </Text>
+          </View>
+        )}
+        onSelect={handleSelectCount}
+        heightRatio={0.4}
+        initialScrollIndex={repeatCount - 1}
+      />
+    </View>
+  );
+};
+
+type EditEventHeaderProps = {
+  id?: string;
+  mode?: "calendar" | "chat";
+};
+
+const EditEventHeader = ({ id, mode }: EditEventHeaderProps) => {
+  const getTitle = () => {
+    if (mode === "chat") return "Edit Proposal";
+    return id ? "Edit Meeting" : "New Meeting";
+  };
+
+  return (
+    <Header className="flex flex-row justify-center items-center">
+      <HeaderButton
+        className="absolute left-6"
+        iconName="arrow-back-outline"
+        iconSize={36}
+        onPress={router.back}
+      />
+      <View className="h-full flex justify-center ml-4">
+        <Text className="text-center text-3xl font-bold">{getTitle()}</Text>
+      </View>
+    </Header>
+  );
+};
+
+type EditEventParams = {
+  id?: string;
+  date?: string;
+  mode?: "calendar" | "chat";
+  eventData?: string;
+  proposalContext?: string;
+};
+
+type ProposalContext = {
+  messageId: string;
+  proposalId: string;
+  conversationId: string;
+};
+
+const EditEventScreen = () => {
+  const { id, date, mode, eventData, proposalContext } =
+    useLocalSearchParams<EditEventParams>();
+  const { theme } = useThemeStore();
+  const updateMessage = useChatStore((state) => state.updateMessage);
+
+  // Only show loading if we need to fetch from API (calendar mode with id)
+  const [isLoading, setIsLoading] = useState(
+    mode !== "chat" && !!id && !eventData,
+  );
+
+  // Initialize dates from URL parameter or use current time
+  const initialDate = date ? new Date(date) : new Date();
+  const initialEndDate = new Date(initialDate.getTime() + 60 * 60 * 1000);
+
+  const [repeatVisible, setRepeatVisible] = useState(false);
+  const [repeatCount, setRepeatCount] = useState(1);
+  const [repeatType, setRepeatType] = useState<RepeatType>("Tag");
+  const [startDate, setStartDate] = useState(initialDate);
+  const [endDate, setEndDate] = useState(initialEndDate);
+  const [title, setTitle] = useState("");
+  const [description, setDescription] = useState("");
+
+  // Helper to populate form from event data
+  const populateFormFromEvent = useCallback((event: CreateEventDTO) => {
+    setStartDate(new Date(event.startTime));
+    setEndDate(new Date(event.endTime));
+    setTitle(event.title);
+    if (event.description) {
+      setDescription(event.description);
+    }
+
+    if (event.recurrenceRule) {
+      setRepeatVisible(true);
+
+      const rrule = rrulestr(event.recurrenceRule);
+      if (rrule.options.interval) {
+        setRepeatCount(rrule.options.interval);
+      }
+      switch (rrule.options.freq) {
+        case Frequency.DAILY:
+          setRepeatType("Tag");
+          break;
+        case Frequency.WEEKLY:
+          setRepeatType("Woche");
+          break;
+        case Frequency.MONTHLY:
+          setRepeatType("Monat");
+          break;
+        case Frequency.YEARLY:
+          setRepeatType("Jahr");
+          break;
+      }
+    }
+  }, []);
+
+  // Load event data based on mode
+  useEffect(() => {
+    // Chat mode: load from eventData JSON parameter
+    if (mode === "chat" && eventData) {
+      try {
+        const event = JSON.parse(eventData) as CreateEventDTO;
+        populateFormFromEvent(event);
+      } catch (error) {
+        console.error("Failed to parse eventData:", error);
+      }
+      return;
+    }
+
+    // Calendar mode with id: fetch from API
+    if (id && !eventData) {
+      const fetchEvent = async () => {
+        try {
+          const event = await EventService.getById(id);
+          populateFormFromEvent({
+            title: event.title,
+            description: event.description,
+            startTime: event.startTime,
+            endTime: event.endTime,
+            recurrenceRule: event.recurrenceRule,
+          });
+        } catch (error) {
+          console.error("Failed to load event: ", error);
+        } finally {
+          setIsLoading(false);
+        }
+      };
+
+      fetchEvent();
+    }
+  }, [id, mode, eventData, populateFormFromEvent]);
+
+  if (isLoading) {
+    return (
+      <BaseBackground>
+        <EditEventHeader id={id} mode={mode} />
+        <View className="flex-1 justify-center items-center">
+          <ActivityIndicator size="large" color={theme.chatBot} />
+        </View>
+      </BaseBackground>
+    );
+  }
+
+  const handleStartDateChange = (date: Date) => {
+    // Keep the time from startDate, update the date part
+    const newStart = new Date(startDate);
+    newStart.setFullYear(date.getFullYear(), date.getMonth(), date.getDate());
+    setStartDate(newStart);
+
+    // If end date is before new start date, adjust it
+    if (endDate < newStart) {
+      const newEnd = new Date(newStart);
+      newEnd.setHours(newStart.getHours() + 1);
+      setEndDate(newEnd);
+    }
+  };
+
+  const handleStartTimeChange = (date: Date) => {
+    // Keep the date from startDate, update the time part
+    const newStart = new Date(startDate);
+    newStart.setHours(date.getHours(), date.getMinutes(), 0, 0);
+    setStartDate(newStart);
+
+    // If end time is before new start time on the same day, adjust it
+    if (endDate <= newStart) {
+      const newEnd = new Date(newStart);
+      newEnd.setHours(newStart.getHours() + 1);
+      setEndDate(newEnd);
+    }
+  };
+
+  const handleEndDateChange = (date: Date) => {
+    // Keep the time from endDate, update the date part
+    const newEnd = new Date(endDate);
+    newEnd.setFullYear(date.getFullYear(), date.getMonth(), date.getDate());
+    setEndDate(newEnd);
+  };
+
+  const handleEndTimeChange = (date: Date) => {
+    // Keep the date from endDate, update the time part
+    const newEnd = new Date(endDate);
+    newEnd.setHours(date.getHours(), date.getMinutes(), 0, 0);
+    setEndDate(newEnd);
+  };
+
+  const handleSave = async () => {
+    const eventObject: CreateEventDTO = {
+      title,
+      description: description === "" ? undefined : description,
+      startTime: startDate,
+      endTime: endDate,
+      recurrenceRule: repeatVisible
+        ? buildRRule(repeatType, repeatCount)
+        : undefined,
+    };
+
+    // Chat mode: update proposal locally and on server
+    if (mode === "chat" && proposalContext) {
+      try {
+        const context = JSON.parse(proposalContext) as ProposalContext;
+
+        // Update locally in ChatStore
+        const currentMessages = getChatStoreState().messages;
+        const message = currentMessages.find((m) => m.id === context.messageId);
+
+        if (message?.proposedChanges) {
+          const updatedProposals = message.proposedChanges.map((p) =>
+            p.id === context.proposalId ? { ...p, event: eventObject } : p,
+          );
+          updateMessage(context.messageId, {
+            proposedChanges: updatedProposals,
+          });
+        }
+
+        // Persist to server
+        await ChatService.updateProposalEvent(
+          context.messageId,
+          context.proposalId,
+          eventObject,
+        );
+
+        router.back();
+      } catch (error) {
+        console.error("Failed to update proposal:", error);
+      }
+      return;
+    }
+
+    // Calendar mode: call API
+    try {
+      if (id) {
+        await EventService.update(id, eventObject);
+      } else {
+        await EventService.create(eventObject);
+      }
+      router.back();
+    } catch (error) {
+      console.error("Creating/Updating event failed!", error);
+    }
+  };
+
+  const getButtonText = () => {
+    if (mode === "chat") {
+      return "Fertig";
+    }
+    return id ? "Aktualisiere Termin" : "Erstelle neuen Termin";
+  };
+
+  return (
+    <BaseBackground>
+      <EditEventHeader id={id} mode={mode} />
+      <View className="h-full flex items-center">
+        {/* Date and Time */}
+        <View className="w-11/12">
+          <EditEventTextField
+            className="h-16 mt-2"
+            titel="Titel"
+            text={title}
+            onValueChange={setTitle}
+          />
+          <PickerRow
+            title="Von"
+            dateValue={startDate}
+            onDateChange={handleStartDateChange}
+            onTimeChange={handleStartTimeChange}
+            showLabels
+          />
+          <PickerRow
+            title="Bis"
+            dateValue={endDate}
+            onDateChange={handleEndDateChange}
+            onTimeChange={handleEndTimeChange}
+          />
+
+          {/* TODO: Reminder */}
+
+          {/* Notes */}
+          <EditEventTextField
+            className="h-64 mt-6"
+            titel="Notizen"
+            text={description}
+            onValueChange={setDescription}
+            multiline
+          />
+
+          {/* Repeat Toggle Button */}
+          <Pressable
+            className="flex flex-row w-1/3 h-10 mt-4 rounded-lg items-center justify-evenly"
+            style={{
+              backgroundColor: repeatVisible
+                ? theme.chatBot
+                : theme.secondaryBg,
+              borderWidth: 1,
+              borderColor: theme.borderPrimary,
+            }}
+            onPress={() => setRepeatVisible(!repeatVisible)}
+          >
+            <Ionicons
+              name="repeat"
+              size={24}
+              color={repeatVisible ? theme.buttonText : theme.textPrimary}
+            />
+            <Text
+              style={{
+                color: repeatVisible ? theme.buttonText : theme.textPrimary,
+              }}
+            >
+              Wiederholen
+            </Text>
+          </Pressable>
+
+          {/* Repeat Selector (shown when toggle is active) */}
+          {repeatVisible && (
+            <RepeatSelector
+              repeatCount={repeatCount}
+              onRepeatCountChange={setRepeatCount}
+              repeatType={repeatType}
+              onRepeatTypeChange={setRepeatType}
+            />
+          )}
+        </View>
+      </View>
+
+      {/* Send new or updated Event */}
+      <View className="absolute bottom-16 w-full h-16">
+        <Pressable
+          className="flex flex-row justify-center items-center py-3"
+          onPress={handleSave}
+          style={{
+            backgroundColor: theme.confirmButton,
+          }}
+        >
+          {mode !== "chat" && (
+            <Ionicons name="add-outline" size={24} color={theme.buttonText} />
+          )}
+          <Text
+            style={{ color: theme.buttonText }}
+            className="font-semibold ml-1"
+          >
+            {getButtonText()}
+          </Text>
+        </Pressable>
+      </View>
+    </BaseBackground>
+  );
+};
+
+export default EditEventScreen;
--- a/apps/client/src/components/CardBase.tsx
+++ b/apps/client/src/components/CardBase.tsx
@@ -8,6 +8,7 @@ type CardBaseProps = {
  title: string;
  subtitle?: string;
  children: ReactNode;
+  attachment?: ReactNode; // renders between children and footer
  footer?: {
    label: string;
    onPress: () => void;
@@ -27,6 +28,7 @@ export const CardBase = ({
  title,
  subtitle,
  children,
+  attachment,
  footer,
  className = "",
  scrollable = false,
@@ -94,6 +96,8 @@ export const CardBase = ({
        contentElement
      )}

+      {attachment}
+
      {/* Footer (optional) */}
      {footer && (
        <Pressable
--- a/apps/client/src/components/DateTimePicker.tsx
+++ b/apps/client/src/components/DateTimePicker.tsx
@@ -0,0 +1,136 @@
+import { useState } from "react";
+import { Platform, Modal, Pressable, Text, View } from "react-native";
+import DateTimePicker, {
+  DateTimePickerEvent,
+} from "@react-native-community/datetimepicker";
+import { useThemeStore } from "../stores/ThemeStore";
+import { THEMES } from "../Themes";
+
+type DateTimePickerButtonProps = {
+  mode: "date" | "time";
+  className?: string;
+  label?: string;
+  value: Date;
+  onChange: (date: Date) => void;
+};
+
+const DateTimePickerButton = ({
+  mode,
+  label,
+  value,
+  onChange,
+  className,
+}: DateTimePickerButtonProps) => {
+  const { theme } = useThemeStore();
+  const [showPicker, setShowPicker] = useState(false);
+  const isDark = theme === THEMES.defaultDark;
+
+  const handleChange = (event: DateTimePickerEvent, selectedDate?: Date) => {
+    if (Platform.OS === "android") {
+      setShowPicker(false);
+    }
+    if (event.type === "set" && selectedDate) {
+      onChange(selectedDate);
+    }
+  };
+
+  const formattedValue =
+    mode === "date"
+      ? value.toLocaleDateString("de-DE", {
+          day: "2-digit",
+          month: "2-digit",
+          year: "numeric",
+        })
+      : value.toLocaleTimeString("de-DE", {
+          hour: "2-digit",
+          minute: "2-digit",
+        });
+
+  return (
+    <View className={className}>
+      {label && (
+        <Text style={{ color: theme.textSecondary }} className="text-sm mb-1">
+          {label}
+        </Text>
+      )}
+      <Pressable
+        onPress={() => setShowPicker(true)}
+        className="w-full rounded-lg px-3 py-2 border"
+        style={{
+          backgroundColor: theme.messageBorderBg,
+          borderColor: theme.borderPrimary,
+        }}
+      >
+        <Text style={{ color: theme.textPrimary }} className="text-base">
+          {formattedValue}
+        </Text>
+      </Pressable>
+
+      {Platform.OS === "ios" ? (
+        <Modal
+          visible={showPicker}
+          transparent
+          animationType="fade"
+          onRequestClose={() => setShowPicker(false)}
+        >
+          <Pressable
+            className="flex-1 justify-end"
+            style={{ backgroundColor: "rgba(0,0,0,0.5)" }}
+            onPress={() => setShowPicker(false)}
+          >
+            <View
+              style={{ backgroundColor: theme.secondaryBg }}
+              className="rounded-t-2xl"
+            >
+              <View className="flex-row justify-end p-2">
+                <Pressable onPress={() => setShowPicker(false)} className="p-2">
+                  <Text
+                    style={{ color: theme.chatBot }}
+                    className="text-lg font-semibold"
+                  >
+                    Fertig
+                  </Text>
+                </Pressable>
+              </View>
+              <DateTimePicker
+                value={value}
+                mode={mode}
+                display="spinner"
+                onChange={handleChange}
+                locale="de-DE"
+                is24Hour={mode === "time"}
+                accentColor={theme.chatBot}
+                textColor={theme.textPrimary}
+                themeVariant={isDark ? "dark" : "light"}
+              />
+            </View>
+          </Pressable>
+        </Modal>
+      ) : (
+        showPicker && (
+          <DateTimePicker
+            value={value}
+            mode={mode}
+            display="default"
+            onChange={handleChange}
+            is24Hour={mode === "time"}
+            accentColor={theme.chatBot}
+            textColor={theme.textPrimary}
+            themeVariant={isDark ? "dark" : "light"}
+          />
+        )
+      )}
+    </View>
+  );
+};
+
+// Convenience wrappers for simpler usage
+export const DatePickerButton = (
+  props: Omit<DateTimePickerButtonProps, "mode">
+) => <DateTimePickerButton {...props} mode="date" />;
+
+export const TimePickerButton = (
+  props: Omit<DateTimePickerButtonProps, "mode">
+) => <DateTimePickerButton {...props} mode="time" />;
+
+export default DateTimePickerButton;
--- a/apps/client/src/components/EventCardBase.tsx
+++ b/apps/client/src/components/EventCardBase.tsx
@@ -3,6 +3,12 @@ import { Feather } from "@expo/vector-icons";
 import { ReactNode } from "react";
 import { useThemeStore } from "../stores/ThemeStore";
 import { CardBase } from "./CardBase";
+import {
+  isMultiDayEvent,
+  formatDateWithWeekday,
+  formatDateWithWeekdayShort,
+  formatTime,
+} from "@calchat/shared";

 type EventCardBaseProps = {
  className?: string;
@@ -14,24 +20,6 @@ type EventCardBaseProps = {
  children?: ReactNode;
 };

-function formatDate(date: Date): string {
-  const d = new Date(date);
-  return d.toLocaleDateString("de-DE", {
-    weekday: "short",
-    day: "2-digit",
-    month: "2-digit",
-    year: "numeric",
-  });
-}
-
-function formatTime(date: Date): string {
-  const d = new Date(date);
-  return d.toLocaleTimeString("de-DE", {
-    hour: "2-digit",
-    minute: "2-digit",
-  });
-}
-
 function formatDuration(start: Date, end: Date): string {
  const startDate = new Date(start);
  const endDate = new Date(end);
@@ -62,6 +50,7 @@ export const EventCardBase = ({
  children,
 }: EventCardBaseProps) => {
  const { theme } = useThemeStore();
+  const multiDay = isMultiDayEvent(startTime, endTime);

  return (
    <CardBase title={title} className={className} borderWidth={2}>
@@ -73,9 +62,16 @@ export const EventCardBase = ({
          color={theme.textPrimary}
          style={{ marginRight: 8 }}
        />
-        <Text style={{ color: theme.textPrimary }}>
-          {formatDate(startTime)}
-        </Text>
+        {multiDay ? (
+          <Text style={{ color: theme.textPrimary }}>
+            {formatDateWithWeekdayShort(startTime)} →{" "}
+            {formatDateWithWeekday(endTime)}
+          </Text>
+        ) : (
+          <Text style={{ color: theme.textPrimary }}>
+            {formatDateWithWeekday(startTime)}
+          </Text>
+        )}
      </View>

      {/* Time with duration */}
@@ -86,10 +82,16 @@ export const EventCardBase = ({
          color={theme.textPrimary}
          style={{ marginRight: 8 }}
        />
-        <Text style={{ color: theme.textPrimary }}>
-          {formatTime(startTime)} - {formatTime(endTime)} (
-          {formatDuration(startTime, endTime)})
-        </Text>
+        {multiDay ? (
+          <Text style={{ color: theme.textPrimary }}>
+            {formatTime(startTime)} → {formatTime(endTime)}
+          </Text>
+        ) : (
+          <Text style={{ color: theme.textPrimary }}>
+            {formatTime(startTime)} - {formatTime(endTime)} (
+            {formatDuration(startTime, endTime)})
+          </Text>
+        )}
      </View>

      {/* Recurring indicator */}
--- a/apps/client/src/components/Header.tsx
+++ b/apps/client/src/components/Header.tsx
@@ -1,6 +1,7 @@
-import { View } from "react-native";
+import { View, Text, Pressable } from "react-native";
 import { useThemeStore } from "../stores/ThemeStore";
-import { ReactNode } from "react";
+import { ComponentProps, ReactNode } from "react";
+import { Ionicons } from "@expo/vector-icons";

 type HeaderProps = {
  children?: ReactNode;
@@ -37,4 +38,54 @@ const Header = (props: HeaderProps) => {
  );
 };

+type HeaderButton = {
+  className?: string;
+  iconName: ComponentProps<typeof Ionicons>["name"];
+  iconSize: number;
+  onPress?: () => void;
+};
+
+export const HeaderButton = (props: HeaderButton) => {
+  const { theme } = useThemeStore();
+
+  return (
+    <Pressable
+      onPress={props.onPress}
+      className={
+        "w-16 h-16 flex items-center justify-center mx-2 rounded-xl border border-solid absolute left-6 " +
+        props.className
+      }
+      style={{
+        backgroundColor: theme.chatBot,
+        borderColor: theme.primeFg,
+        // iOS shadow
+        shadowColor: theme.shadowColor,
+        shadowOffset: { width: 0, height: 4 },
+        shadowOpacity: 0.3,
+        shadowRadius: 8,
+        // Android shadow
+        elevation: 6,
+      }}
+    >
+      <Ionicons
+        name={props.iconName}
+        size={props.iconSize}
+        color={theme.buttonText}
+      />
+    </Pressable>
+  );
+};
+
+type SimpleHeaderProps = {
+  text: string;
+};
+
+export const SimpleHeader = ({ text }: SimpleHeaderProps) => (
+  <Header>
+    <View className="h-full flex justify-center">
+      <Text className="text-center text-3xl font-bold">{text}</Text>
+    </View>
+  </Header>
+);
+
 export default Header;
--- a/apps/client/src/components/ModalBase.tsx
+++ b/apps/client/src/components/ModalBase.tsx
@@ -9,6 +9,7 @@ type ModalBaseProps = {
  title: string;
  subtitle?: string;
  children: ReactNode;
+  attachment?: ReactNode;
  footer?: {
    label: string;
    onPress: () => void;
@@ -23,6 +24,7 @@ export const ModalBase = ({
  title,
  subtitle,
  children,
+  attachment,
  footer,
  scrollable,
  maxContentHeight,
@@ -55,6 +57,7 @@ export const ModalBase = ({
          <CardBase
            title={title}
            subtitle={subtitle}
+            attachment={attachment}
            footer={footer}
            scrollable={scrollable}
            maxContentHeight={maxContentHeight}
--- a/apps/client/src/components/ProposedEventCard.tsx
+++ b/apps/client/src/components/ProposedEventCard.tsx
@@ -1,44 +1,31 @@
 import { View, Text, Pressable } from "react-native";
-import { ProposedEventChange, RecurringDeleteMode } from "@calchat/shared";
+import { Feather } from "@expo/vector-icons";
+import { ProposedEventChange, formatDate } from "@calchat/shared";
+import { rrulestr } from "rrule";
 import { useThemeStore } from "../stores/ThemeStore";
 import { EventCardBase } from "./EventCardBase";

-const DELETE_MODE_LABELS: Record<RecurringDeleteMode, string> = {
-  single: "Nur dieses Vorkommen",
-  future: "Dieses & zukuenftige",
-  all: "Alle Vorkommen",
-};
-
 type ProposedEventCardProps = {
  proposedChange: ProposedEventChange;
-  onConfirm: () => void;
+  onConfirm: (proposal: ProposedEventChange) => void;
  onReject: () => void;
+  onEdit?: (proposal: ProposedEventChange) => void;
 };

-const DeleteModeBadge = ({ mode }: { mode: RecurringDeleteMode }) => {
-  const { theme } = useThemeStore();
-  return (
-    <View
-      className="self-start px-2 py-1 rounded-md mb-2"
-      style={{ backgroundColor: theme.rejectButton }}
-    >
-      <Text style={{ color: theme.buttonText }} className="text-xs font-medium">
-        {DELETE_MODE_LABELS[mode]}
-      </Text>
-    </View>
-  );
-};
-
-const ConfirmRejectButtons = ({
+const ActionButtons = ({
  isDisabled,
  respondedAction,
+  showEdit,
  onConfirm,
  onReject,
+  onEdit,
 }: {
  isDisabled: boolean;
  respondedAction?: "confirm" | "reject";
+  showEdit: boolean;
  onConfirm: () => void;
  onReject: () => void;
+  onEdit?: () => void;
 }) => {
  const { theme } = useThemeStore();
  return (
@@ -75,6 +62,19 @@ const ConfirmRejectButtons = ({
          Ablehnen
        </Text>
      </Pressable>
+      {showEdit && onEdit && (
+        <Pressable
+          onPress={onEdit}
+          className="py-2 px-3 rounded-lg items-center"
+          style={{
+            backgroundColor: theme.secondaryBg,
+            borderWidth: 1,
+            borderColor: theme.borderPrimary,
+          }}
+        >
+          <Feather name="edit-2" size={18} color={theme.textPrimary} />
+        </Pressable>
+      )}
    </View>
  );
 };
@@ -83,16 +83,23 @@ export const ProposedEventCard = ({
  proposedChange,
  onConfirm,
  onReject,
+  onEdit,
 }: ProposedEventCardProps) => {
+  const { theme } = useThemeStore();
  const event = proposedChange.event;
-  // respondedAction is now part of the proposedChange
  const isDisabled = !!proposedChange.respondedAction;

-  // Show delete mode badge for delete actions on recurring events
-  const showDeleteModeBadge =
+  // For delete/single action, the occurrenceDate becomes a new exception
+  const newExceptionDate =
    proposedChange.action === "delete" &&
-    event?.isRecurring &&
-    proposedChange.deleteMode;
+    proposedChange.deleteMode === "single" &&
+    proposedChange.occurrenceDate;
+
+  // For update actions, check if a new UNTIL date is being set
+  const newUntilDate =
+    proposedChange.action === "update" &&
+    event?.recurrenceRule &&
+    rrulestr(event.recurrenceRule).options.until;

  if (!event) {
    return null;
@@ -106,16 +113,43 @@ export const ProposedEventCard = ({
        startTime={event.startTime}
        endTime={event.endTime}
        description={event.description}
-        isRecurring={event.isRecurring}
+        isRecurring={!!event.recurrenceRule}
      >
-        {showDeleteModeBadge && (
-          <DeleteModeBadge mode={proposedChange.deleteMode!} />
+        {/* Show new exception date for delete/single actions */}
+        {newExceptionDate && (
+          <View className="flex-row items-center mb-2">
+            <Feather
+              name="plus-circle"
+              size={16}
+              color={theme.confirmButton}
+              style={{ marginRight: 8 }}
+            />
+            <Text style={{ color: theme.confirmButton }} className="font-medium">
+              Neue Ausnahme: {formatDate(new Date(proposedChange.occurrenceDate!))}
+            </Text>
+          </View>
        )}
-        <ConfirmRejectButtons
+        {/* Show new UNTIL date for update actions */}
+        {newUntilDate && (
+          <View className="flex-row items-center mb-2">
+            <Feather
+              name="plus-circle"
+              size={16}
+              color={theme.confirmButton}
+              style={{ marginRight: 8 }}
+            />
+            <Text style={{ color: theme.confirmButton }} className="font-medium">
+              Neues Ende: {formatDate(newUntilDate)}
+            </Text>
+          </View>
+        )}
+        <ActionButtons
          isDisabled={isDisabled}
          respondedAction={proposedChange.respondedAction}
-          onConfirm={onConfirm}
+          showEdit={proposedChange.action !== "delete" && !isDisabled}
+          onConfirm={() => onConfirm(proposedChange)}
          onReject={onReject}
+          onEdit={onEdit ? () => onEdit(proposedChange) : undefined}
        />
      </EventCardBase>
    </View>
--- a/apps/client/src/components/ScrollableDropdown.tsx
+++ b/apps/client/src/components/ScrollableDropdown.tsx
@@ -0,0 +1,107 @@
+import { useRef, useEffect } from "react";
+import { Modal, Pressable, Animated, useWindowDimensions } from "react-native";
+import { FlashList } from "@shopify/flash-list";
+import { useThemeStore } from "../stores/ThemeStore";
+import { Theme } from "../Themes";
+
+export type ScrollableDropdownProps<T> = {
+  visible: boolean;
+  onClose: () => void;
+  position: {
+    top?: number;
+    bottom?: number;
+    left: number;
+    width: number;
+  };
+  data: T[];
+  keyExtractor: (item: T) => string;
+  renderItem: (item: T, theme: Theme) => React.ReactNode;
+  onSelect: (item: T) => void;
+  height?: number;
+  heightRatio?: number; // Alternative: fraction of screen height (0-1)
+  initialScrollIndex?: number;
+  // Infinite scroll (optional)
+  onEndReached?: () => void;
+  onStartReached?: () => void;
+};
+
+export const ScrollableDropdown = <T,>({
+  visible,
+  onClose,
+  position,
+  data,
+  keyExtractor,
+  renderItem,
+  onSelect,
+  height = 200,
+  heightRatio,
+  initialScrollIndex = 0,
+  onEndReached,
+  onStartReached,
+}: ScrollableDropdownProps<T>) => {
+  const { theme } = useThemeStore();
+  const { height: screenHeight } = useWindowDimensions();
+  const heightAnim = useRef(new Animated.Value(0)).current;
+  const listRef = useRef<React.ComponentRef<typeof FlashList<T>>>(null);
+
+  // Calculate actual height: use heightRatio if provided, otherwise fall back to height
+  const actualHeight = heightRatio ? screenHeight * heightRatio : height;
+  // Calculate top position: use top if provided, otherwise calculate from bottom
+  const topValue =
+    position.top ?? screenHeight - actualHeight - (position.bottom ?? 0);
+
+  useEffect(() => {
+    if (visible) {
+      Animated.timing(heightAnim, {
+        toValue: actualHeight,
+        duration: 200,
+        useNativeDriver: false,
+      }).start();
+    } else {
+      heightAnim.setValue(0);
+    }
+  }, [visible, heightAnim, actualHeight]);
+
+  return (
+    <Modal
+      visible={visible}
+      transparent={true}
+      animationType="none"
+      onRequestClose={onClose}
+    >
+      <Pressable className="flex-1 rounded-lg" onPress={onClose}>
+        <Animated.View
+          className="absolute overflow-hidden"
+          style={{
+            top: topValue,
+            left: position.left,
+            width: position.width,
+            height: heightAnim,
+            backgroundColor: theme.primeBg,
+            borderWidth: 2,
+            borderColor: theme.borderPrimary,
+            borderRadius: 8,
+          }}
+        >
+          <FlashList
+            className="w-full"
+            style={{ borderRadius: 8 }}
+            ref={listRef}
+            keyExtractor={keyExtractor}
+            data={data}
+            initialScrollIndex={initialScrollIndex}
+            onEndReachedThreshold={0.5}
+            onEndReached={onEndReached}
+            onStartReachedThreshold={0.5}
+            onStartReached={onStartReached}
+            renderItem={({ item }) => (
+              <Pressable onPress={() => onSelect(item)}>
+                {renderItem(item, theme)}
+              </Pressable>
+            )}
+          />
+        </Animated.View>
+      </Pressable>
+    </Modal>
+  );
+};
--- a/apps/client/src/hooks/useDropdownPosition.ts
+++ b/apps/client/src/hooks/useDropdownPosition.ts
@@ -0,0 +1,37 @@
+import { useCallback, useRef, useState } from "react";
+import { View } from "react-native";
+
+type DropdownPosition = {
+  top: number;
+  left: number;
+  width: number;
+};
+
+/**
+ * Hook for managing dropdown position measurement and visibility.
+ * @param widthMultiplier - Multiply the measured width (default: 1)
+ */
+export const useDropdownPosition = (widthMultiplier = 1) => {
+  const [visible, setVisible] = useState(false);
+  const [position, setPosition] = useState<DropdownPosition>({
+    top: 0,
+    left: 0,
+    width: 0,
+  });
+  const ref = useRef<View>(null);
+
+  const open = useCallback(() => {
+    ref.current?.measureInWindow((x, y, width, height) => {
+      setPosition({
+        top: y + height,
+        left: x,
+        width: width * widthMultiplier,
+      });
+      setVisible(true);
+    });
+  }, [widthMultiplier]);
+
+  const close = useCallback(() => setVisible(false), []);
+
+  return { ref, visible, position, open, close };
+};
--- a/apps/client/src/services/ChatService.ts
+++ b/apps/client/src/services/ChatService.ts
@@ -85,4 +85,15 @@ export const ChatService = {

    return ApiClient.get<ChatMessage[]>(url);
  },
+
+  updateProposalEvent: async (
+    messageId: string,
+    proposalId: string,
+    event: CreateEventDTO,
+  ): Promise<ChatMessage> => {
+    return ApiClient.put<ChatMessage>(`/chat/messages/${messageId}/proposal`, {
+      proposalId,
+      event,
+    });
+  },
 };
--- a/apps/server/src/ai/utils/eventFormatter.ts
+++ b/apps/server/src/ai/utils/eventFormatter.ts
@@ -1,11 +1,12 @@
-import { CalendarEvent } from "@calchat/shared";
+import {
+  CalendarEvent,
+  formatDate,
+  formatTime,
+  formatDateTime,
+} from "@calchat/shared";

-// German date/time formatting helpers
-export const formatDate = (d: Date) => d.toLocaleDateString("de-DE");
-export const formatTime = (d: Date) =>
-  d.toLocaleTimeString("de-DE", { hour: "2-digit", minute: "2-digit" });
-export const formatDateTime = (d: Date) =>
-  `${formatDate(d)} ${d.toLocaleTimeString("de-DE")}`;
+// Re-export for backwards compatibility
+export { formatDate, formatTime, formatDateTime };

 /**
 * Format a list of events for display in the system prompt.
--- a/apps/server/src/ai/utils/systemPrompt.ts
+++ b/apps/server/src/ai/utils/systemPrompt.ts
@@ -46,13 +46,20 @@ WICHTIG - Wiederkehrende Termine (RRULE):
  2. "Arbeit" Fr 9:00-13:00 (RRULE mit BYDAY=FR)
 - Nutze NIEMALS BYHOUR/BYMINUTE in RRULE - diese überschreiben die Startzeit nicht wie erwartet!
 - Gültige RRULE-Optionen: FREQ (DAILY/WEEKLY/MONTHLY/YEARLY), BYDAY (MO,TU,WE,TH,FR,SA,SU), INTERVAL, COUNT, UNTIL
+- UNTIL Format: YYYYMMDDTHHMMSSZ (UTC) z.B. UNTIL=20260310T000000Z
+- WICHTIG: Schreibe die RRULE NIEMALS in das description-Feld! Nutze IMMER das recurrenceRule-Feld!

 WICHTIG - Antwortformat:
 - Halte deine Textantworten SEHR KURZ (1-2 Sätze maximal)
 - Die Event-Details (Titel, Datum, Uhrzeit, Beschreibung) werden dem Benutzer automatisch in separaten Karten angezeigt
 - Wiederhole NIEMALS die Event-Details im Text! Der Benutzer sieht sie bereits in den Karten
- Gute Beispiele: "Alles klar!" oder "Hier sind deine Termine:"
- Schlechte Beispiele: Lange Listen mit allen Terminen und ihren Details im Text
+- Verwende kontextbezogene Antworten in der GEGENWARTSFORM je nach Aktion:
+  - Bei Termin-Erstellung: "Ich schlage folgenden Termin vor:" oder "Neuer Termin:"
+  - Bei Termin-Änderung: "Ich schlage folgende Änderung vor:" oder "Änderung:"
+  - Bei Termin-Löschung: "Ich schlage vor, diesen Termin zu löschen:" oder "Löschung:"
+  - Bei Übersichten: "Hier sind deine Termine:"
+- WICHTIG: Verwende NIEMALS Vergangenheitsform wie "Ich habe ... vorgeschlagen" - immer Gegenwartsform!
+- Schlechte Beispiele: "Alles klar!" (zu unspezifisch), lange Listen mit Termin-Details im Text
 - Bei Rückfragen oder wenn keine Termine erstellt werden, kannst du ausführlicher antworten

 Existierende Termine des Benutzers:
--- a/apps/server/src/ai/utils/toolDefinitions.ts
+++ b/apps/server/src/ai/utils/toolDefinitions.ts
@@ -94,10 +94,6 @@ export const TOOL_DEFINITIONS: ToolDefinition[] = [
          type: "string",
          description: "Optional event description",
        },
-        isRecurring: {
-          type: "boolean",
-          description: "Whether this is a recurring event",
-        },
        recurrenceRule: {
          type: "string",
          description: "RRULE format string for recurring events",
@@ -131,7 +127,12 @@ export const TOOL_DEFINITIONS: ToolDefinition[] = [
        },
        description: {
          type: "string",
-          description: "New description (optional)",
+          description: "New description (optional). NEVER put RRULE here!",
+        },
+        recurrenceRule: {
+          type: "string",
+          description:
+            "RRULE format string (optional). Use to add UNTIL or modify recurrence. Format: FREQ=DAILY;UNTIL=20260310T000000Z",
        },
      },
      required: ["eventId"],
--- a/apps/server/src/ai/utils/toolExecutor.ts
+++ b/apps/server/src/ai/utils/toolExecutor.ts
@@ -57,7 +57,6 @@ export function executeToolCall(
        startTime: new Date(args.startTime as string),
        endTime: new Date(args.endTime as string),
        description: args.description as string | undefined,
-        isRecurring: args.isRecurring as boolean | undefined,
        recurrenceRule: args.recurrenceRule as string | undefined,
      };
      const dateStr = formatDate(event.startTime);
@@ -88,6 +87,7 @@ export function executeToolCall(
        updates.startTime = new Date(args.startTime as string);
      if (args.endTime) updates.endTime = new Date(args.endTime as string);
      if (args.description) updates.description = args.description;
+      if (args.recurrenceRule) updates.recurrenceRule = args.recurrenceRule;

      // Build event object for display (merge existing with updates)
      const displayEvent = {
@@ -96,7 +96,9 @@ export function executeToolCall(
        endTime: (updates.endTime as Date) || existingEvent.endTime,
        description:
          (updates.description as string) || existingEvent.description,
-        isRecurring: existingEvent.isRecurring,
+        recurrenceRule:
+          (updates.recurrenceRule as string) || existingEvent.recurrenceRule,
+        exceptionDates: existingEvent.exceptionDates,
      };

      return {
@@ -124,7 +126,7 @@ export function executeToolCall(

      // Build descriptive content based on delete mode
      let modeDescription = "";
-      if (existingEvent.isRecurring) {
+      if (existingEvent.recurrenceRule) {
        switch (deleteMode) {
          case "single":
            modeDescription = " (nur dieses Vorkommen)";
@@ -148,10 +150,11 @@ export function executeToolCall(
            startTime: existingEvent.startTime,
            endTime: existingEvent.endTime,
            description: existingEvent.description,
-            isRecurring: existingEvent.isRecurring,
+            recurrenceRule: existingEvent.recurrenceRule,
+            exceptionDates: existingEvent.exceptionDates,
          },
-          deleteMode: existingEvent.isRecurring ? deleteMode : undefined,
-          occurrenceDate: existingEvent.isRecurring
+          deleteMode: existingEvent.recurrenceRule ? deleteMode : undefined,
+          occurrenceDate: existingEvent.recurrenceRule
            ? occurrenceDate
            : undefined,
        },
--- a/apps/server/src/controllers/ChatController.ts
+++ b/apps/server/src/controllers/ChatController.ts
@@ -35,6 +35,10 @@ export class ChatController {
    try {
      const userId = req.user!.userId;
      const { conversationId, messageId } = req.params;
+
+      // DEBUG: Log incoming request body to trace deleteMode issue
+      log.debug({ body: req.body }, "confirmEvent request body");
+
      const {
        proposalId,
        action,
@@ -146,4 +150,33 @@ export class ChatController {
      }
    }
  }
+
+  async updateProposalEvent(
+    req: AuthenticatedRequest,
+    res: Response,
+  ): Promise<void> {
+    try {
+      const { messageId } = req.params;
+      const { proposalId, event } = req.body as {
+        proposalId: string;
+        event: CreateEventDTO;
+      };
+      const message = await this.chatService.updateProposalEvent(
+        messageId,
+        proposalId,
+        event,
+      );
+      if (message) {
+        res.json(message);
+      } else {
+        res.status(404).json({ error: "Message or proposal not found" });
+      }
+    } catch (error) {
+      log.error(
+        { error, messageId: req.params.messageId },
+        "Error updating proposal event",
+      );
+      res.status(500).json({ error: "Failed to update proposal event" });
+    }
+  }
 }
--- a/apps/server/src/repositories/mongo/MongoChatRepository.ts
+++ b/apps/server/src/repositories/mongo/MongoChatRepository.ts
@@ -2,6 +2,7 @@ import {
  ChatMessage,
  Conversation,
  CreateMessageDTO,
+  CreateEventDTO,
  GetMessagesOptions,
  UpdateMessageDTO,
 } from "@calchat/shared";
@@ -82,4 +83,17 @@ export class MongoChatRepository implements ChatRepository {
    );
    return doc ? (doc.toJSON() as unknown as ChatMessage) : null;
  }
+
+  async updateProposalEvent(
+    messageId: string,
+    proposalId: string,
+    event: CreateEventDTO,
+  ): Promise<ChatMessage | null> {
+    const doc = await ChatMessageModel.findOneAndUpdate(
+      { _id: messageId, "proposedChanges.id": proposalId },
+      { $set: { "proposedChanges.$.event": event } },
+      { new: true },
+    );
+    return doc ? (doc.toJSON() as unknown as ChatMessage) : null;
+  }
 }
--- a/apps/server/src/repositories/mongo/models/ChatModel.ts
+++ b/apps/server/src/repositories/mongo/models/ChatModel.ts
@@ -23,8 +23,8 @@ const EventSchema = new Schema<CreateEventDTO>(
    startTime: { type: Date, required: true },
    endTime: { type: Date, required: true },
    note: { type: String },
-    isRecurring: { type: Boolean },
    recurrenceRule: { type: String },
+    exceptionDates: { type: [String] },
  },
  { _id: false },
 );
@@ -36,7 +36,6 @@ const UpdatesSchema = new Schema<UpdateEventDTO>(
    startTime: { type: Date },
    endTime: { type: Date },
    note: { type: String },
-    isRecurring: { type: Boolean },
    recurrenceRule: { type: String },
  },
  { _id: false },
@@ -57,6 +56,11 @@ const ProposedChangeSchema = new Schema<ProposedEventChange>(
      type: String,
      enum: ["confirm", "reject"],
    },
+    deleteMode: {
+      type: String,
+      enum: ["single", "future", "all"],
+    },
+    occurrenceDate: { type: String },
  },
  { _id: false },
 );
--- a/apps/server/src/repositories/mongo/models/EventModel.ts
+++ b/apps/server/src/repositories/mongo/models/EventModel.ts
@@ -2,16 +2,22 @@ import mongoose, { Schema, Document, Model } from "mongoose";
 import { CalendarEvent } from "@calchat/shared";
 import { IdVirtual } from "./types";

-export interface EventDocument extends Omit<CalendarEvent, "id">, Document {
+interface EventVirtuals extends IdVirtual {
+  isRecurring: boolean;
+}
+
+export interface EventDocument
+  extends Omit<CalendarEvent, "id" | "isRecurring">,
+    Document {
  toJSON(): CalendarEvent;
 }

 const EventSchema = new Schema<
  EventDocument,
-  Model<EventDocument, {}, {}, IdVirtual>,
+  Model<EventDocument, {}, {}, EventVirtuals>,
  {},
  {},
-  IdVirtual
+  EventVirtuals
 >(
  {
    userId: {
@@ -39,10 +45,6 @@ const EventSchema = new Schema<
    note: {
      type: String,
    },
-    isRecurring: {
-      type: Boolean,
-      default: false,
-    },
    recurrenceRule: {
      type: String,
    },
@@ -59,6 +61,11 @@ const EventSchema = new Schema<
          return this._id.toString();
        },
      },
+      isRecurring: {
+        get() {
+          return !!this.recurrenceRule;
+        },
+      },
    },
    toJSON: {
      virtuals: true,
--- a/apps/server/src/routes/chat.routes.ts
+++ b/apps/server/src/routes/chat.routes.ts
@@ -19,6 +19,9 @@ export function createChatRoutes(chatController: ChatController): Router {
  router.get("/conversations/:id", (req, res) =>
    chatController.getConversation(req, res),
  );
+  router.put("/messages/:messageId/proposal", (req, res) =>
+    chatController.updateProposalEvent(req, res),
+  );

  return router;
 }
--- a/apps/server/src/services/ChatService.ts
+++ b/apps/server/src/services/ChatService.ts
@@ -27,8 +27,33 @@ let responseIndex = 0;
 // Static test responses (event proposals)
 const staticResponses: TestResponse[] = [
  // {{{
+  // === SPORT TEST SCENARIO (3 steps) ===
+  // Response 0: Wiederkehrendes Event - jeden Mittwoch Sport
+  {
+    content:
+      "Super! Ich erstelle dir einen wiederkehrenden Termin für Sport jeden Mittwoch:",
+    proposedChanges: [
+      {
+        id: "sport-create",
+        action: "create",
+        event: {
+          title: "Sport",
+          startTime: getDay("Wednesday", 1, 18, 0),
+          endTime: getDay("Wednesday", 1, 19, 30),
+          description: "Wöchentliches Training",
+          recurrenceRule: "FREQ=WEEKLY;BYDAY=WE",
+        },
+      },
+    ],
+  },
+  // Response 1: Ausnahme hinzufügen (2 Wochen später) - DYNAMIC placeholder
+  { content: "" },
+  // Response 2: UNTIL hinzufügen (nach 6 Wochen) - DYNAMIC placeholder
+  { content: "" },
+  // Response 3: Weitere Ausnahme in 2 Wochen - DYNAMIC placeholder
+  { content: "" },
  // === MULTI-EVENT TEST RESPONSES ===
-  // Response 0: 3 Meetings an verschiedenen Tagen
+  // Response 3: 3 Meetings an verschiedenen Tagen
  {
    content: "Alles klar! Ich erstelle dir 3 Team-Meetings für diese Woche:",
    proposedChanges: [
@@ -132,7 +157,6 @@ const staticResponses: TestResponse[] = [
          startTime: getDay("Monday", 1, 7, 0),
          endTime: getDay("Monday", 1, 8, 0),
          description: "Morgen-Yoga",
-          isRecurring: true,
          recurrenceRule: "FREQ=WEEKLY;BYDAY=MO,WE,FR",
        },
      },
@@ -144,7 +168,6 @@ const staticResponses: TestResponse[] = [
          startTime: getDay("Tuesday", 1, 18, 0),
          endTime: getDay("Tuesday", 1, 19, 0),
          description: "Abendlauf im Park",
-          isRecurring: true,
          recurrenceRule: "FREQ=WEEKLY;BYDAY=TU,TH",
        },
      },
@@ -189,7 +212,6 @@ const staticResponses: TestResponse[] = [
          title: "Badezimmer putzen",
          startTime: getDay("Saturday", 1, 10, 0),
          endTime: getDay("Saturday", 1, 11, 0),
-          isRecurring: true,
          recurrenceRule: "FREQ=WEEKLY;BYDAY=SA",
        },
      },
@@ -229,7 +251,6 @@ const staticResponses: TestResponse[] = [
          title: "Mamas Geburtstag",
          startTime: getDay("Thursday", 2, 0, 0),
          endTime: getDay("Thursday", 2, 23, 59),
-          isRecurring: true,
          recurrenceRule: "FREQ=YEARLY",
        },
      },
@@ -247,7 +268,6 @@ const staticResponses: TestResponse[] = [
          title: "Fitnessstudio Probetraining",
          startTime: getDay("Tuesday", 1, 18, 0),
          endTime: getDay("Tuesday", 1, 19, 30),
-          isRecurring: true,
          recurrenceRule: "FREQ=WEEKLY;BYDAY=TU;COUNT=8",
        },
      },
@@ -301,7 +321,6 @@ const staticResponses: TestResponse[] = [
          title: "Spanischkurs VHS",
          startTime: getDay("Thursday", 1, 19, 0),
          endTime: getDay("Thursday", 1, 20, 30),
-          isRecurring: true,
          recurrenceRule: "FREQ=WEEKLY;BYDAY=TH,SA;COUNT=8",
        },
      },
@@ -319,12 +338,130 @@ async function getTestResponse(
 ): Promise<TestResponse> {
  const responseIdx = index % staticResponses.length;

-  // Dynamic responses: fetch events from DB and format
+  // === SPORT TEST SCENARIO (Dynamic responses) ===
+  // Response 1: Add exception to "Sport" (2 weeks later)
+  if (responseIdx === 1) {
+    const events = await eventRepo.findByUserId(userId);
+    const sportEvent = events.find((e) => e.title === "Sport");
+    if (sportEvent) {
+      // Calculate date 2 weeks from the first occurrence
+      const exceptionDate = new Date(sportEvent.startTime);
+      exceptionDate.setDate(exceptionDate.getDate() + 14);
+      const exceptionDateStr = exceptionDate.toISOString().split("T")[0];
+
+      return {
+        content:
+          "Verstanden! Ich füge eine Ausnahme für den Sport-Termin in 2 Wochen hinzu:",
+        proposedChanges: [
+          {
+            id: "sport-exception",
+            action: "delete",
+            eventId: sportEvent.id,
+            deleteMode: "single",
+            occurrenceDate: exceptionDateStr,
+            event: {
+              title: sportEvent.title,
+              startTime: exceptionDate,
+              endTime: new Date(
+                exceptionDate.getTime() + 90 * 60 * 1000,
+              ), // +90 min
+              description: sportEvent.description,
+              recurrenceRule: sportEvent.recurrenceRule,
+              exceptionDates: sportEvent.exceptionDates,
+            },
+          },
+        ],
+      };
+    }
+    return {
+      content: "Ich konnte keinen Termin 'Sport' finden. Bitte erstelle ihn zuerst.",
+    };
+  }
+
+  // Response 2: Add UNTIL to "Sport" (after 6 weeks total)
+  if (responseIdx === 2) {
+    const events = await eventRepo.findByUserId(userId);
+    const sportEvent = events.find((e) => e.title === "Sport");
+    if (sportEvent) {
+      // Calculate UNTIL date: 6 weeks from start
+      const untilDate = new Date(sportEvent.startTime);
+      untilDate.setDate(untilDate.getDate() + 42); // 6 weeks
+      const untilStr = untilDate.toISOString().replace(/[-:]/g, "").split(".")[0] + "Z";
+
+      const newRule = `FREQ=WEEKLY;BYDAY=WE;UNTIL=${untilStr}`;
+
+      return {
+        content:
+          "Alles klar! Ich beende die Sport-Serie nach 6 Wochen:",
+        proposedChanges: [
+          {
+            id: "sport-until",
+            action: "update",
+            eventId: sportEvent.id,
+            updates: { recurrenceRule: newRule },
+            event: {
+              title: sportEvent.title,
+              startTime: sportEvent.startTime,
+              endTime: sportEvent.endTime,
+              description: sportEvent.description,
+              recurrenceRule: newRule,
+              exceptionDates: sportEvent.exceptionDates,
+            },
+          },
+        ],
+      };
+    }
+    return {
+      content: "Ich konnte keinen Termin 'Sport' finden. Bitte erstelle ihn zuerst.",
+    };
+  }
+
+  // Response 3: Add another exception to "Sport" (2 weeks after the first exception)
  if (responseIdx === 3) {
+    const events = await eventRepo.findByUserId(userId);
+    const sportEvent = events.find((e) => e.title === "Sport");
+    if (sportEvent) {
+      // Calculate date 4 weeks from the first occurrence (2 weeks after the first exception)
+      const exceptionDate = new Date(sportEvent.startTime);
+      exceptionDate.setDate(exceptionDate.getDate() + 28); // 4 weeks
+      const exceptionDateStr = exceptionDate.toISOString().split("T")[0];
+
+      return {
+        content:
+          "Alles klar! Ich füge eine weitere Ausnahme für den Sport-Termin hinzu:",
+        proposedChanges: [
+          {
+            id: "sport-exception-2",
+            action: "delete",
+            eventId: sportEvent.id,
+            deleteMode: "single",
+            occurrenceDate: exceptionDateStr,
+            event: {
+              title: sportEvent.title,
+              startTime: exceptionDate,
+              endTime: new Date(
+                exceptionDate.getTime() + 90 * 60 * 1000,
+              ), // +90 min
+              description: sportEvent.description,
+              recurrenceRule: sportEvent.recurrenceRule,
+              exceptionDates: sportEvent.exceptionDates,
+            },
+          },
+        ],
+      };
+    }
+    return {
+      content: "Ich konnte keinen Termin 'Sport' finden. Bitte erstelle ihn zuerst.",
+    };
+  }
+
+  // Dynamic responses: fetch events from DB and format
+  // (Note: indices shifted by +3 due to new sport responses)
+  if (responseIdx === 6) {
    return { content: await getWeeksOverview(eventRepo, userId, 2) };
  }

-  if (responseIdx === 4) {
+  if (responseIdx === 7) {
    // Delete "Meeting mit Jens"
    const events = await eventRepo.findByUserId(userId);
    const jensEvent = events.find((e) => e.title === "Meeting mit Jens");
@@ -341,7 +478,6 @@ async function getTestResponse(
              startTime: jensEvent.startTime,
              endTime: jensEvent.endTime,
              description: jensEvent.description,
-              isRecurring: jensEvent.isRecurring,
            },
          },
        ],
@@ -350,11 +486,11 @@ async function getTestResponse(
    return { content: "Ich konnte keinen Termin 'Meeting mit Jens' finden." };
  }

-  if (responseIdx === 8) {
+  if (responseIdx === 11) {
    return { content: await getWeeksOverview(eventRepo, userId, 1) };
  }

-  if (responseIdx === 10) {
+  if (responseIdx === 13) {
    // Update "Telefonat mit Mama" +3 days and change time to 13:00
    const events = await eventRepo.findByUserId(userId);
    const mamaEvent = events.find((e) => e.title === "Telefonat mit Mama");
@@ -387,7 +523,7 @@ async function getTestResponse(
    return { content: "Ich konnte keinen Termin 'Telefonat mit Mama' finden." };
  }

-  if (responseIdx === 13) {
+  if (responseIdx === 16) {
    const now = new Date();
    return {
      content: await getMonthOverview(
@@ -571,4 +707,12 @@ export class ChatService {

    return this.chatRepo.getMessages(conversationId, options);
  }
+
+  async updateProposalEvent(
+    messageId: string,
+    proposalId: string,
+    event: CreateEventDTO,
+  ): Promise<ChatMessage | null> {
+    return this.chatRepo.updateProposalEvent(messageId, proposalId, event);
+  }
 }
--- a/apps/server/src/services/interfaces/ChatRepository.ts
+++ b/apps/server/src/services/interfaces/ChatRepository.ts
@@ -2,6 +2,7 @@ import {
  ChatMessage,
  Conversation,
  CreateMessageDTO,
+  CreateEventDTO,
  GetMessagesOptions,
  UpdateMessageDTO,
 } from "@calchat/shared";
@@ -32,4 +33,10 @@ export interface ChatRepository {
    proposalId: string,
    respondedAction: "confirm" | "reject",
  ): Promise<ChatMessage | null>;
+
+  updateProposalEvent(
+    messageId: string,
+    proposalId: string,
+    event: CreateEventDTO,
+  ): Promise<ChatMessage | null>;
 }
--- a/apps/server/src/utils/recurrenceExpander.ts
+++ b/apps/server/src/utils/recurrenceExpander.ts
@@ -44,9 +44,13 @@ export function expandRecurringEvents(
    const endTime = new Date(event.endTime);
    const duration = endTime.getTime() - startTime.getTime();

+    // For multi-day events: adjust range start back by event duration
+    // to find events that start before rangeStart but extend into the range
+    const adjustedRangeStart = new Date(rangeStart.getTime() - duration);
+
    if (!event.isRecurring || !event.recurrenceRule) {
-      // Non-recurring event: add as-is if within range
-      if (startTime >= rangeStart && startTime <= rangeEnd) {
+      // Non-recurring event: add if it overlaps with the range
+      if (endTime >= rangeStart && startTime <= rangeEnd) {
        expanded.push({
          ...event,
          occurrenceStart: startTime,
@@ -64,9 +68,11 @@ export function expandRecurringEvents(
        `DTSTART:${formatRRuleDateString(startTime)}\nRRULE:${ruleString}`,
      );

-      // Get occurrences within the range (using fake UTC dates)
+      // Get occurrences within the adjusted range (using fake UTC dates)
+      // Use adjustedRangeStart to catch multi-day events that start before
+      // rangeStart but still extend into the range
      const occurrences = rule.between(
-        toRRuleDate(rangeStart),
+        toRRuleDate(adjustedRangeStart),
        toRRuleDate(rangeEnd),
        true, // inclusive
      );
@@ -78,6 +84,11 @@ export function expandRecurringEvents(
        const occurrenceStart = fromRRuleDate(occurrence);
        const occurrenceEnd = new Date(occurrenceStart.getTime() + duration);

+        // Only include if occurrence actually overlaps with the original range
+        if (occurrenceEnd < rangeStart || occurrenceStart > rangeEnd) {
+          continue;
+        }
+
        // Skip if this occurrence is in the exception dates
        const dateKey = formatDateKey(occurrenceStart);
        if (exceptionSet.has(dateKey)) {
--- a/package-lock.json
+++ b/package-lock.json
@@ -23,6 +23,7 @@
      "dependencies": {
        "@calchat/shared": "*",
        "@expo/vector-icons": "^15.0.3",
+        "@react-native-community/datetimepicker": "8.4.4",
        "@react-navigation/bottom-tabs": "^7.4.0",
        "@react-navigation/elements": "^2.6.3",
        "@react-navigation/native": "^7.1.8",
@@ -52,6 +53,7 @@
        "react-native-screens": "~4.16.0",
        "react-native-web": "~0.21.0",
        "react-native-worklets": "0.5.1",
+        "rrule": "^2.8.1",
        "zustand": "^5.0.9"
      },
      "devDependencies": {
@@ -2647,6 +2649,29 @@
        }
      }
    },
+    "node_modules/@react-native-community/datetimepicker": {
+      "version": "8.4.4",
+      "resolved": "https://registry.npmjs.org/@react-native-community/datetimepicker/-/datetimepicker-8.4.4.tgz",
+      "integrity": "sha512-bc4ZixEHxZC9/qf5gbdYvIJiLZ5CLmEsC3j+Yhe1D1KC/3QhaIfGDVdUcid0PdlSoGOSEq4VlB93AWyetEyBSQ==",
+      "license": "MIT",
+      "dependencies": {
+        "invariant": "^2.2.4"
+      },
+      "peerDependencies": {
+        "expo": ">=52.0.0",
+        "react": "*",
+        "react-native": "*",
+        "react-native-windows": "*"
+      },
+      "peerDependenciesMeta": {
+        "expo": {
+          "optional": true
+        },
+        "react-native-windows": {
+          "optional": true
+        }
+      }
+    },
    "node_modules/@react-native/assets-registry": {
      "version": "0.81.5",
      "license": "MIT",
@@ -10537,6 +10562,8 @@
    },
    "node_modules/rrule": {
      "version": "2.8.1",
+      "resolved": "https://registry.npmjs.org/rrule/-/rrule-2.8.1.tgz",
+      "integrity": "sha512-hM3dHSBMeaJ0Ktp7W38BJZ7O1zOgaFEsn41PDk+yHoEtfLV+PoJt9E9xAlZiWgf/iqEqionN0ebHFZIDAp+iGw==",
      "license": "BSD-3-Clause",
      "dependencies": {
        "tslib": "^2.4.0"
@@ -12535,7 +12562,10 @@
    },
    "packages/shared": {
      "name": "@calchat/shared",
-      "version": "1.0.0"
+      "version": "1.0.0",
+      "dependencies": {
+        "rrule": "^2.8.1"
+      }
    }
  }
 }
--- a/packages/shared/package.json
+++ b/packages/shared/package.json
@@ -7,5 +7,8 @@
  "exports": {
    ".": "./src/index.ts",
    "./*": "./src/*"
+  },
+  "dependencies": {
+    "rrule": "^2.8.1"
  }
 }
--- a/packages/shared/src/models/CalendarEvent.ts
+++ b/packages/shared/src/models/CalendarEvent.ts
@@ -26,8 +26,8 @@ export interface CreateEventDTO {
  startTime: Date;
  endTime: Date;
  note?: string;
-  isRecurring?: boolean;
  recurrenceRule?: string;
+  exceptionDates?: string[]; // For display in proposals
 }

 export interface UpdateEventDTO {
@@ -36,7 +36,6 @@ export interface UpdateEventDTO {
  startTime?: Date;
  endTime?: Date;
  note?: string;
-  isRecurring?: boolean;
  recurrenceRule?: string;
  exceptionDates?: string[];
 }
--- a/packages/shared/src/utils/dateHelpers.ts
+++ b/packages/shared/src/utils/dateHelpers.ts
@@ -34,3 +34,15 @@ export function getDay(
  result.setHours(hour, minute, 0, 0);
  return result;
 }
+
+/**
+ * Check if an event spans multiple days.
+ * Compares dates at midnight to determine if start and end are on different calendar days.
+ */
+export function isMultiDayEvent(start: Date, end: Date): boolean {
+  const startDate = new Date(start);
+  const endDate = new Date(end);
+  startDate.setHours(0, 0, 0, 0);
+  endDate.setHours(0, 0, 0, 0);
+  return startDate.getTime() !== endDate.getTime();
+}
--- a/packages/shared/src/utils/formatters.ts
+++ b/packages/shared/src/utils/formatters.ts
@@ -0,0 +1,71 @@
+/**
+ * German date/time formatting helpers.
+ * Used across client and server.
+ */
+
+/**
+ * Format date as DD.MM.YYYY
+ */
+export function formatDate(date: Date): string {
+  const d = new Date(date);
+  return d.toLocaleDateString("de-DE", {
+    day: "2-digit",
+    month: "2-digit",
+    year: "numeric",
+  });
+}
+
+/**
+ * Format time as HH:MM
+ */
+export function formatTime(date: Date): string {
+  const d = new Date(date);
+  return d.toLocaleTimeString("de-DE", {
+    hour: "2-digit",
+    minute: "2-digit",
+  });
+}
+
+/**
+ * Format date and time as DD.MM.YYYY HH:MM:SS
+ */
+export function formatDateTime(date: Date): string {
+  const d = new Date(date);
+  return `${formatDate(d)} ${d.toLocaleTimeString("de-DE")}`;
+}
+
+/**
+ * Format date with weekday as "Mo., DD.MM.YYYY"
+ */
+export function formatDateWithWeekday(date: Date): string {
+  const d = new Date(date);
+  return d.toLocaleDateString("de-DE", {
+    weekday: "short",
+    day: "2-digit",
+    month: "2-digit",
+    year: "numeric",
+  });
+}
+
+/**
+ * Format date as DD.MM. (short, without year)
+ */
+export function formatDateShort(date: Date): string {
+  const d = new Date(date);
+  return d.toLocaleDateString("de-DE", {
+    day: "2-digit",
+    month: "2-digit",
+  });
+}
+
+/**
+ * Format date with weekday short as "Mo., DD.MM."
+ */
+export function formatDateWithWeekdayShort(date: Date): string {
+  const d = new Date(date);
+  return d.toLocaleDateString("de-DE", {
+    weekday: "short",
+    day: "2-digit",
+    month: "2-digit",
+  });
+}
--- a/packages/shared/src/utils/index.ts
+++ b/packages/shared/src/utils/index.ts
@@ -1 +1,3 @@
 export * from "./dateHelpers";
+export * from "./formatters";
+export * from "./rruleHelpers";
--- a/packages/shared/src/utils/rruleHelpers.ts
+++ b/packages/shared/src/utils/rruleHelpers.ts
@@ -0,0 +1,29 @@
+/**
+ * RRULE building and parsing helpers.
+ */
+
+export type RepeatType = "Tag" | "Woche" | "Monat" | "Jahr";
+
+const REPEAT_TYPE_TO_FREQ: Record<RepeatType, string> = {
+  Tag: "DAILY",
+  Woche: "WEEKLY",
+  Monat: "MONTHLY",
+  Jahr: "YEARLY",
+};
+
+/**
+ * Build an RRULE string from repeat count and type.
+ *
+ * @param repeatType - The type of repetition (Tag, Woche, Monat, Jahr)
+ * @param interval - The interval between repetitions (default: 1)
+ * @returns RRULE string like "FREQ=WEEKLY;INTERVAL=2"
+ */
+export function buildRRule(repeatType: RepeatType, interval: number = 1): string {
+  const freq = REPEAT_TYPE_TO_FREQ[repeatType];
+
+  if (interval <= 1) {
+    return `FREQ=${freq}`;
+  }
+
+  return `FREQ=${freq};INTERVAL=${interval}`;
+}