implement chat messaging with event proposals

- Add functional chat with server communication and test responses - Add ProposedEventCard component for confirm/reject actions - Move Constants (Day, Month) from client to shared package - Add dateHelpers utility for weekday calculations - Extend Themes.tsx with button and text colors - Update CLAUDE.md with current implementation status - Add *.tsbuildinfo to .gitignore
2026-01-04 00:01:26 +01:00
parent e553103470
commit c33508a227
17 changed files with 456 additions and 295 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 node_modules
+*.tsbuildinfo
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -78,7 +78,9 @@ src/
 │   ├── BaseBackground.tsx      # Common screen wrapper
 │   ├── Header.tsx              # Header component
 │   ├── EventCard.tsx           # Event card for calendar display
-│   └── EventConfirmDialog.tsx  # AI-proposed event confirmation modal
+│   ├── EventConfirmDialog.tsx  # AI-proposed event confirmation modal
+│   └── ProposedEventCard.tsx   # Inline event proposal with confirm/reject buttons
+├── Themes.tsx                  # Centralized color/theme definitions
 ├── services/
 │   ├── index.ts                # Re-exports all services
 │   ├── ApiClient.ts            # HTTP client (get, post, put, delete)
@@ -159,13 +161,17 @@ src/
 ```
 src/
 ├── index.ts
-└── models/
+├── models/
+│   ├── index.ts
+│   ├── User.ts           # User, CreateUserDTO, LoginDTO, AuthResponse
+│   ├── CalendarEvent.ts  # CalendarEvent, CreateEventDTO, UpdateEventDTO
+│   ├── ChatMessage.ts    # ChatMessage, Conversation, SendMessageDTO, CreateMessageDTO,
+│   │                     # GetMessagesOptions, ChatResponse, ConversationSummary,
+│   │                     # ProposedEventChange, EventAction
+│   └── Constants.ts      # DAYS, MONTHS, Day, Month, DAY_INDEX
+└── utils/
    ├── index.ts
-    ├── User.ts           # User, CreateUserDTO, LoginDTO, AuthResponse
-    ├── CalendarEvent.ts  # CalendarEvent, CreateEventDTO, UpdateEventDTO
-    └── ChatMessage.ts    # ChatMessage, Conversation, SendMessageDTO, CreateMessageDTO,
-                          # GetMessagesOptions, ChatResponse, ConversationSummary,
-                          # ProposedEventChange, EventAction
+    └── dateHelpers.ts    # getDay() - get date for specific weekday relative to today
 ```

 **Key Types:**
@@ -177,6 +183,8 @@ src/
 - `CreateEventDTO`: Used for creating events AND for AI-proposed events
 - `GetMessagesOptions`: Cursor-based pagination with `before?: string` and `limit?: number`
 - `ConversationSummary`: id, lastMessage?, createdAt? (for conversation list)
+- `Day`: "Monday" | "Tuesday" | ... | "Sunday"
+- `Month`: "January" | "February" | ... | "December"

 ### Database Abstraction

@@ -230,24 +238,30 @@ MONGODB_URI=mongodb://root:mongoose@localhost:27017/calchat?authSource=admin
  - `utils/password`: hash(), compare() using bcrypt
  - `utils/jwt`: signToken() (verifyToken() pending)
  - `dotenv` integration for environment variables
+  - `ChatController`: sendMessage(), confirmEvent(), rejectEvent()
+  - `ChatService`: processMessage() with test responses, confirmEvent(), rejectEvent()
 - **Stubbed (TODO):**
  - `AuthMiddleware.authenticate()`: Currently uses fake user for testing
  - `AuthController`: refresh(), logout()
  - `AuthService`: refreshToken()
-  - All Chat and Event functionality
+  - `ChatController`: getConversations(), getConversation()
+  - `MongoChatRepository`: Database persistence for chat
+  - All Event functionality
 - **Not started:**
-  - `ChatController`, `ChatService`, `MongoChatRepository`
  - `EventController`, `EventService`, `MongoEventRepository`
-  - `ClaudeAdapter` (AI integration)
+  - `ClaudeAdapter` (AI integration - currently using test responses)

-**Shared:** Types and DTOs defined and exported.
+**Shared:** Types, DTOs, constants (Day, Month), and date utilities defined and exported.

-**Frontend:** Skeleton complete with file-based routing structure:
+**Frontend:**
 - Tab navigation (Chat, Calendar) implemented with basic UI
 - Calendar screen has month navigation and grid display (partially functional)
- Chat screen has message list UI with FlashList (mock data only)
+- Chat screen functional with FlashList, message sending, and event confirm/reject
+- `ApiClient`: get(), post() implemented
+- `ChatService`: sendMessage(), confirmEvent(), rejectEvent() implemented
+- `ProposedEventCard`: Displays proposed events with confirm/reject buttons, theming support
+- `Themes.tsx`: Centralized color definitions including button colors
 - Auth screens (Login, Register), Event Detail, and Note screens exist as skeletons
- Services (ApiClient, AuthService, EventService, ChatService) defined with `throw new Error('Not implemented')`
 - Zustand stores (AuthStore, EventsStore) defined with `throw new Error('Not implemented')`
 - Components (EventCard, EventConfirmDialog) exist as skeletons

--- a/apps/client/src/Themes.tsx
+++ b/apps/client/src/Themes.tsx
@@ -5,6 +5,12 @@ type Theme = {
  messageBorderBg: string,
  placeholderBg: string,
  calenderBg: string,
+  confirmButton: string,
+  rejectButton: string,
+  disabledButton: string,
+  buttonText: string,
+  textSecondary: string,
+  textMuted: string,
 }

 const defaultLight: Theme = {
@@ -14,6 +20,12 @@ const defaultLight: Theme = {
  messageBorderBg: "#FFFFFF",
  placeholderBg: "#D9D9D9",
  calenderBg: "#FBD5B2",
+  confirmButton: "#22c55e",
+  rejectButton: "#ef4444",
+  disabledButton: "#ccc",
+  buttonText: "#fff",
+  textSecondary: "#666",
+  textMuted: "#888",
 }

 let currentTheme: Theme = defaultLight;
--- a/apps/client/src/app/(tabs)/calendar.tsx
+++ b/apps/client/src/app/(tabs)/calendar.tsx
@@ -1,5 +1,5 @@
 import { Animated, Modal, Pressable, Text, View } from "react-native";
-import { DAYS, MONTHS, Month } from "../../Constants";
+import { DAYS, MONTHS, Month } from "@caldav/shared";
 import Header from "../../components/Header";
 import React, { useEffect, useMemo, useRef, useState } from "react";
 import currentTheme from "../../Themes";
--- a/apps/client/src/app/(tabs)/chat.tsx
+++ b/apps/client/src/app/(tabs)/chat.tsx
@@ -1,9 +1,12 @@
-import { View, Text, TextInput } from "react-native";
+import { View, Text, TextInput, Pressable } from "react-native";
 import currentTheme from "../../Themes";
 import { useState } from "react";
 import Header from "../../components/Header";
 import BaseBackground from "../../components/BaseBackground";
 import { FlashList } from "@shopify/flash-list";
+import { ChatService } from "../../services";
+import { ProposedEventChange } from "@caldav/shared";
+import { ProposedEventCard } from "../../components/ProposedEventCard";

 // TODO: better shadows for everything
 // (maybe with extra library because of differences between android and ios)
@@ -11,239 +14,91 @@ import { FlashList } from "@shopify/flash-list";
 // TODO: create new messages

 type BubbleSide = "left" | "right";
+
 type ChatMessageProps = {
  side: BubbleSide;
-  width: number;
-  height: number;
+  content: string;
+  proposedChange?: ProposedEventChange;
+  respondedAction?: "confirm" | "reject";
+  onConfirm?: () => void;
+  onReject?: () => void;
 };

-type MessageData = {
+type MessageData = ChatMessageProps & {
  id: string;
-  side: BubbleSide;
-  width: number;
-  height: number;
+  conversationId?: string;
 };

-// NOTE: only for testing
-const getRandomInt = (min: number, max: number) => {
-  min = Math.ceil(min);
-  max = Math.floor(max);
-  return Math.floor(Math.random() * (max - min + 1)) + min;
+type ChatInputProps = {
+  onSend: (text: string) => void;
 };

-const randomWidth = () => getRandomInt(100, 400);
-const randomHeight = () => getRandomInt(50, 100);
-
-const messages: MessageData[] = [
-  // {{{
-  {
-    id: "1",
-    side: "left",
-    width: randomWidth(),
-    height: randomHeight(),
-  },
-  {
-    id: "2",
-    side: "right",
-    width: randomWidth(),
-    height: randomHeight(),
-  },
-  {
-    id: "3",
-    side: "left",
-    width: randomWidth(),
-    height: randomHeight(),
-  },
-  {
-    id: "4",
-    side: "right",
-    width: randomWidth(),
-    height: randomHeight(),
-  },
-  {
-    id: "5",
-    side: "left",
-    width: randomWidth(),
-    height: randomHeight(),
-  },
-  {
-    id: "6",
-    side: "right",
-    width: randomWidth(),
-    height: randomHeight(),
-  },
-  {
-    id: "7",
-    side: "left",
-    width: randomWidth(),
-    height: randomHeight(),
-  },
-  {
-    id: "8",
-    side: "right",
-    width: randomWidth(),
-    height: randomHeight(),
-  },
-  {
-    id: "9",
-    side: "left",
-    width: randomWidth(),
-    height: randomHeight(),
-  },
-  {
-    id: "10",
-    side: "right",
-    width: randomWidth(),
-    height: randomHeight(),
-  },
-  // {
-  //   id: "11",
-  //   side: "left",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "12",
-  //   side: "right",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "13",
-  //   side: "left",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "14",
-  //   side: "right",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "15",
-  //   side: "left",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "16",
-  //   side: "right",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "17",
-  //   side: "left",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "18",
-  //   side: "right",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "19",
-  //   side: "left",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "20",
-  //   side: "right",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "21",
-  //   side: "left",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "22",
-  //   side: "right",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "23",
-  //   side: "left",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "24",
-  //   side: "right",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "25",
-  //   side: "left",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "26",
-  //   side: "right",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "27",
-  //   side: "left",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "28",
-  //   side: "right",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "29",
-  //   side: "left",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "30",
-  //   side: "right",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "31",
-  //   side: "left",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "32",
-  //   side: "right",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "33",
-  //   side: "left",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  // {
-  //   id: "34",
-  //   side: "right",
-  //   width: randomWidth(),
-  //   height: randomHeight(),
-  // },
-  //, width: randomWidth, height: getRandomInt(50, 500) }}}
-];
-
 const Chat = () => {
+  const [messages, setMessages] = useState<MessageData[]>([]);
+
+  const handleEventResponse = async (
+    action: "confirm" | "reject",
+    messageId: string,
+    conversationId: string
+  ) => {
+    // Mark message as responded (optimistic update)
+    setMessages((prev) =>
+      prev.map((msg) =>
+        msg.id === messageId ? { ...msg, respondedAction: action } : msg
+      )
+    );
+
+    try {
+      const response =
+        action === "confirm"
+          ? await ChatService.confirmEvent(conversationId, messageId)
+          : await ChatService.rejectEvent(conversationId, messageId);
+
+      const botMessage: MessageData = {
+        id: response.message.id,
+        side: "left",
+        content: response.message.content,
+        conversationId: response.conversationId,
+      };
+      setMessages((prev) => [...prev, botMessage]);
+    } catch (error) {
+      console.error(`Failed to ${action} event:`, error);
+      // Revert on error
+      setMessages((prev) =>
+        prev.map((msg) =>
+          msg.id === messageId ? { ...msg, respondedAction: undefined } : msg
+        )
+      );
+    }
+  };
+
+  const handleSend = async (text: string) => {
+    // Show user message immediately
+    const userMessage: MessageData = {
+      id: Date.now().toString(),
+      side: "right",
+      content: text,
+    };
+    setMessages((prev) => [...prev, userMessage]);
+
+    try {
+      // Fetch server response
+      const response = await ChatService.sendMessage({ content: text });
+
+      // Show bot response
+      const botMessage: MessageData = {
+        id: response.message.id,
+        side: "left",
+        content: response.message.content,
+        proposedChange: response.message.proposedChange,
+        conversationId: response.conversationId,
+      };
+      setMessages((prev) => [...prev, botMessage]);
+    } catch (error) {
+      console.error("Failed to send message:", error);
+    }
+  };
+
  return (
    <BaseBackground>
      <ChatHeader />
@@ -252,18 +107,20 @@ const Chat = () => {
        renderItem={({ item }) => (
          <ChatMessage
            side={item.side}
-            width={item.width}
-            height={item.height}
+            content={item.content}
+            proposedChange={item.proposedChange}
+            respondedAction={item.respondedAction}
+            onConfirm={() =>
+              handleEventResponse("confirm", item.id, item.conversationId!)
+            }
+            onReject={() =>
+              handleEventResponse("reject", item.id, item.conversationId!)
+            }
          />
        )}
-        maintainVisibleContentPosition={{
-          autoscrollToBottomThreshold: 0.2,
-          startRenderingFromBottom: true,
-        }}
        keyExtractor={(item) => item.id}
-        // extraData={selectedId} might need this later for re-rendering
      />
-      <ChatInput />
+      <ChatInput onSend={handleSend} />
    </BaseBackground>
  );
 };
@@ -297,51 +154,81 @@ const ChatHeader = () => {
  );
 };

-const ChatInput = () => {
-  const [text, onChangeText] = useState("Nachricht");
+const MIN_INPUT_HEIGHT = 40;
+const MAX_INPUT_HEIGHT = 150;
+
+const ChatInput = ({ onSend }: ChatInputProps) => {
+  const [text, setText] = useState("");
+
+  const handleSend = () => {
+    if (text.trim()) {
+      onSend(text.trim());
+      setText("");
+    }
+  };

  return (
-    <View className="flex flex-row w-full h-8 my-2">
+    <View className="flex flex-row w-full items-end my-2 px-2">
      <TextInput
-        className="w-4/5 h-full border border-solid rounded-2xl mx-2 px-2"
+        className="flex-1 border border-solid rounded-2xl px-3 py-2 mr-2"
        style={{
          backgroundColor: currentTheme.messageBorderBg,
+          minHeight: MIN_INPUT_HEIGHT,
+          maxHeight: MAX_INPUT_HEIGHT,
+          textAlignVertical: "top",
        }}
-        onChangeText={onChangeText}
+        onChangeText={setText}
        value={text}
+        placeholder="Nachricht..."
+        placeholderTextColor="#999"
+        multiline
      />
-      <View
-        className="w-8 h-full rounded-2xl"
-        style={{
-          backgroundColor: currentTheme.placeholderBg,
-        }}
-      ></View>
+      <Pressable onPress={handleSend}>
+        <View
+          className="w-10 h-10 rounded-full items-center justify-center"
+          style={{
+            backgroundColor: currentTheme.placeholderBg,
+          }}
+        />
+      </Pressable>
    </View>
  );
 };

-const ChatMessage = (props: ChatMessageProps) => {
+const ChatMessage = ({
+  side,
+  content,
+  proposedChange,
+  respondedAction,
+  onConfirm,
+  onReject,
+}: ChatMessageProps) => {
  const borderColor =
-    props.side === "left" ? currentTheme.chatBot : currentTheme.primeFg;
+    side === "left" ? currentTheme.chatBot : currentTheme.primeFg;
  const selfSide =
-    props.side === "left"
+    side === "left"
      ? "self-start ml-2 rounded-bl-sm"
      : "self-end mr-2 rounded-br-sm";

  return (
    <View
-      className={
-        `bg-white border-2 border-solid rounded-xl my-2 ` + `${selfSide}`
-      }
+      className={`bg-white border-2 border-solid rounded-xl my-2 ${selfSide}`}
      style={{
-        width: props.width,
-        height: props.height,
        borderColor: borderColor,
-
+        maxWidth: "80%",
        elevation: 8,
      }}
    >
-      <Text className="p-1">Lorem Ipsum Dolor sit amet</Text>
+      <Text className="p-2">{content}</Text>
+
+      {proposedChange && onConfirm && onReject && (
+        <ProposedEventCard
+          proposedChange={proposedChange}
+          respondedAction={respondedAction}
+          onConfirm={onConfirm}
+          onReject={onReject}
+        />
+      )}
    </View>
  );
 };
--- a/apps/client/src/components/ProposedEventCard.tsx
+++ b/apps/client/src/components/ProposedEventCard.tsx
@@ -0,0 +1,86 @@
+import { View, Text, Pressable } from "react-native";
+import { ProposedEventChange } from "@caldav/shared";
+import currentTheme from "../Themes";
+
+type ProposedEventCardProps = {
+  proposedChange: ProposedEventChange;
+  respondedAction?: "confirm" | "reject";
+  onConfirm: () => void;
+  onReject: () => void;
+};
+
+function formatDateTime(date?: Date): string {
+  if (!date) return "";
+  const d = new Date(date);
+  return d.toLocaleDateString("de-DE", {
+    weekday: "long",
+    day: "2-digit",
+    month: "2-digit",
+    hour: "2-digit",
+    minute: "2-digit",
+  });
+}
+
+export const ProposedEventCard = ({
+  proposedChange,
+  respondedAction,
+  onConfirm,
+  onReject,
+}: ProposedEventCardProps) => {
+  const event = proposedChange.event;
+  const isDisabled = !!respondedAction;
+
+  return (
+    <View
+      className="border-t p-2 mt-2"
+      style={{ borderTopColor: currentTheme.placeholderBg }}
+    >
+      {/* Event Details */}
+      <Text className="font-bold text-base">{event?.title}</Text>
+      <Text style={{ color: currentTheme.textSecondary }}>
+        {formatDateTime(event?.startTime)}
+      </Text>
+      {event?.isRecurring && (
+        <Text style={{ color: currentTheme.textMuted }} className="text-sm">
+          Wiederkehrend
+        </Text>
+      )}
+
+      {/* Buttons */}
+      <View className="flex-row mt-3 gap-2">
+        <Pressable
+          onPress={onConfirm}
+          disabled={isDisabled}
+          className="flex-1 py-2 rounded-lg items-center"
+          style={{
+            backgroundColor: isDisabled
+              ? currentTheme.disabledButton
+              : currentTheme.confirmButton,
+            borderWidth: respondedAction === "confirm" ? 2 : 0,
+            borderColor: currentTheme.confirmButton,
+          }}
+        >
+          <Text style={{ color: currentTheme.buttonText }} className="font-medium">
+            Annehmen
+          </Text>
+        </Pressable>
+        <Pressable
+          onPress={onReject}
+          disabled={isDisabled}
+          className="flex-1 py-2 rounded-lg items-center"
+          style={{
+            backgroundColor: isDisabled
+              ? currentTheme.disabledButton
+              : currentTheme.rejectButton,
+            borderWidth: respondedAction === "reject" ? 2 : 0,
+            borderColor: currentTheme.rejectButton,
+          }}
+        >
+          <Text style={{ color: currentTheme.buttonText }} className="font-medium">
+            Ablehnen
+          </Text>
+        </Pressable>
+      </View>
+    </View>
+  );
+};
--- a/apps/client/src/services/ApiClient.ts
+++ b/apps/client/src/services/ApiClient.ts
@@ -1,5 +1,5 @@
 const API_BASE_URL =
-  process.env.EXPO_PUBLIC_API_URL || "http://localhost:3000/api";
+  process.env.EXPO_PUBLIC_API_URL || "http://localhost:3001/api";

 type HttpMethod = "GET" | "POST" | "PUT" | "DELETE";

@@ -9,11 +9,24 @@ interface RequestOptions {
 }

 async function request<T>(
-  _method: HttpMethod,
-  _endpoint: string,
-  _options?: RequestOptions,
+  method: HttpMethod,
+  endpoint: string,
+  options?: RequestOptions,
 ): Promise<T> {
-  throw new Error("Not implemented");
+  const response = await fetch(`${API_BASE_URL}${endpoint}`, {
+    method,
+    headers: {
+      "Content-Type": "application/json",
+      ...options?.headers,
+    },
+    body: options?.body ? JSON.stringify(options.body) : undefined,
+  });
+
+  if (!response.ok) {
+    throw new Error(`HTTP ${response.status}`);
+  }
+
+  return response.json();
 }

 export const ApiClient = {
--- a/apps/client/src/services/ChatService.ts
+++ b/apps/client/src/services/ChatService.ts
@@ -4,26 +4,26 @@ import {
  ChatMessage,
  ConversationSummary,
  GetMessagesOptions,
-  CalendarEvent,
-} from '@caldav/shared';
+} from "@caldav/shared";
+import { ApiClient } from "./ApiClient";

 export const ChatService = {
-  sendMessage: async (_data: SendMessageDTO): Promise<ChatResponse> => {
-    throw new Error('Not implemented');
+  sendMessage: async (data: SendMessageDTO): Promise<ChatResponse> => {
+    return ApiClient.post<ChatResponse>("/chat/message", data);
  },

  confirmEvent: async (
-    _conversationId: string,
-    _messageId: string
-  ): Promise<CalendarEvent> => {
-    throw new Error('Not implemented');
+    conversationId: string,
+    messageId: string
+  ): Promise<ChatResponse> => {
+    return ApiClient.post<ChatResponse>(`/chat/confirm/${conversationId}/${messageId}`);
  },

  rejectEvent: async (
-    _conversationId: string,
-    _messageId: string
-  ): Promise<void> => {
-    throw new Error('Not implemented');
+    conversationId: string,
+    messageId: string
+  ): Promise<ChatResponse> => {
+    return ApiClient.post<ChatResponse>(`/chat/reject/${conversationId}/${messageId}`);
  },

  getConversations: async (): Promise<ConversationSummary[]> => {
--- a/apps/server/docker/mongo/compose.yml
+++ b/apps/server/docker/mongo/compose.yml
@@ -19,7 +19,7 @@ services:
    image: mongo-express:latest
    restart: always
    ports:
-      - "8081:8081"
+      - "8083:8083"
    environment:
      ME_CONFIG_MONGODB_URL: mongodb://root:mongoose@mongo:27017/
      ME_CONFIG_BASICAUTH_ENABLED: true
--- a/apps/server/src/app.ts
+++ b/apps/server/src/app.ts
@@ -15,6 +15,21 @@ const mongoUri = process.env.MONGODB_URI || 'mongodb://localhost:27017/caldav';
 // Middleware
 app.use(express.json());

+// CORS - only needed for web browser development
+// Native mobile apps don't send Origin headers and aren't affected by CORS
+if (process.env.NODE_ENV !== 'production') {
+  app.use((req, res, next) => {
+    res.header('Access-Control-Allow-Origin', '*');
+    res.header('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS');
+    res.header('Access-Control-Allow-Headers', 'Content-Type, Authorization');
+    if (req.method === 'OPTIONS') {
+      res.sendStatus(200);
+      return;
+    }
+    next();
+  });
+}
+
 // Initialize repositories
 const userRepo = new MongoUserRepository();
 const eventRepo = new MongoEventRepository();
--- a/apps/server/src/controllers/ChatController.ts
+++ b/apps/server/src/controllers/ChatController.ts
@@ -1,4 +1,5 @@
 import { Response } from 'express';
+import { SendMessageDTO } from '@caldav/shared';
 import { ChatService } from '../services';
 import { AuthenticatedRequest } from '../middleware';

@@ -6,15 +7,36 @@ export class ChatController {
  constructor(private chatService: ChatService) {}

  async sendMessage(req: AuthenticatedRequest, res: Response): Promise<void> {
-    throw new Error('Not implemented');
+    try {
+      const userId = req.user!.userId;
+      const data: SendMessageDTO = req.body;
+      const response = await this.chatService.processMessage(userId, data);
+      res.json(response);
+    } catch (error) {
+      res.status(500).json({ error: 'Failed to process message' });
+    }
  }

  async confirmEvent(req: AuthenticatedRequest, res: Response): Promise<void> {
-    throw new Error('Not implemented');
+    try {
+      const userId = req.user!.userId;
+      const { conversationId, messageId } = req.params;
+      const response = await this.chatService.confirmEvent(userId, conversationId, messageId);
+      res.json(response);
+    } catch (error) {
+      res.status(500).json({ error: 'Failed to confirm event' });
+    }
  }

  async rejectEvent(req: AuthenticatedRequest, res: Response): Promise<void> {
-    throw new Error('Not implemented');
+    try {
+      const userId = req.user!.userId;
+      const { conversationId, messageId } = req.params;
+      const response = await this.chatService.rejectEvent(userId, conversationId, messageId);
+      res.json(response);
+    } catch (error) {
+      res.status(500).json({ error: 'Failed to reject event' });
+    }
  }

  async getConversations(req: AuthenticatedRequest, res: Response): Promise<void> {
--- a/apps/server/src/services/ChatService.ts
+++ b/apps/server/src/services/ChatService.ts
@@ -1,6 +1,49 @@
-import { ChatMessage, ChatResponse, SendMessageDTO, CalendarEvent, ConversationSummary, GetMessagesOptions } from '@caldav/shared';
+import { ChatMessage, ChatResponse, SendMessageDTO, ConversationSummary, GetMessagesOptions, ProposedEventChange, getDay } from '@caldav/shared';
 import { ChatRepository, EventRepository, AIProvider } from './interfaces';

+// Test responses array (cycles through responses)
+let responseIndex = 0;
+
+const testResponses: Array<{ content: string; proposedChange?: ProposedEventChange }> = [
+  // {{{
+  // Response 1: Meeting mit Jens - next Friday 14:00
+  {
+    content: "Alles klar! Ich erstelle dir einen Termin für das Meeting mit Jens am nächsten Freitag um 14:00 Uhr:",
+    proposedChange: {
+      action: 'create',
+      event: {
+        title: "Meeting mit Jens",
+        startTime: getDay('Friday', 1, 14, 0),
+        endTime: getDay('Friday', 1, 15, 0),
+        description: "Arbeitstreffen",
+      }
+    }
+  },
+  // Response 2: Recurring event - every Saturday 10:00
+  {
+    content: "Verstanden! Ich erstelle einen wiederkehrenden Termin: Jeden Samstag um 10:00 Uhr Badezimmer putzen:",
+    proposedChange: {
+      action: 'create',
+      event: {
+        title: "Badezimmer putzen",
+        startTime: getDay('Saturday', 1, 10, 0),
+        endTime: getDay('Saturday', 1, 11, 0),
+        isRecurring: true,
+        recurrenceRule: "FREQ=WEEKLY;BYDAY=SA",
+      }
+    }
+  },
+  // Response 3: Calendar overview (text only, no proposedChange)
+  {
+    content: "Hier sind deine Termine für die nächsten 2 Wochen:\n\n" +
+      "Freitag, 10.01. - 14:00 Uhr: Meeting mit Jens\n" +
+      "Samstag, 11.01. - 10:00 Uhr: Badezimmer putzen\n" +
+      "Samstag, 18.01. - 10:00 Uhr: Badezimmer putzen\n\n" +
+      "Insgesamt 3 Termine.",
+  },
+  // }}}
+];
+
 export class ChatService {
  constructor(
    private chatRepo: ChatRepository,
@@ -9,15 +52,38 @@ export class ChatService {
  ) {}

  async processMessage(userId: string, data: SendMessageDTO): Promise<ChatResponse> {
-    throw new Error('Not implemented');
+    const response = testResponses[responseIndex % testResponses.length];
+    responseIndex++;
+
+    const message: ChatMessage = {
+      id: Date.now().toString(),
+      conversationId: data.conversationId || 'temp-conv-id',
+      sender: 'assistant',
+      content: response.content,
+      proposedChange: response.proposedChange,
+    };
+
+    return { message, conversationId: message.conversationId };
  }

-  async confirmEvent(userId: string, conversationId: string, messageId: string): Promise<CalendarEvent> {
-    throw new Error('Not implemented');
+  async confirmEvent(userId: string, conversationId: string, messageId: string): Promise<ChatResponse> {
+    const message: ChatMessage = {
+      id: Date.now().toString(),
+      conversationId,
+      sender: 'assistant',
+      content: 'Der Vorschlag wurde angenommen.',
+    };
+    return { message, conversationId };
  }

-  async rejectEvent(conversationId: string, messageId: string): Promise<void> {
-    throw new Error('Not implemented');
+  async rejectEvent(userId: string, conversationId: string, messageId: string): Promise<ChatResponse> {
+    const message: ChatMessage = {
+      id: Date.now().toString(),
+      conversationId,
+      sender: 'assistant',
+      content: 'Der Vorschlag wurde abgelehnt.',
+    };
+    return { message, conversationId };
  }

  async getConversations(userId: string): Promise<ConversationSummary[]> {
--- a/packages/shared/src/index.ts
+++ b/packages/shared/src/index.ts
@@ -1 +1,2 @@
 export * from './models';
+export * from './utils';
--- a/packages/shared/src/models/Constants.ts
+++ b/packages/shared/src/models/Constants.ts
@@ -26,3 +26,14 @@ export const DAYS = [
 ] as const;

 export type Day = (typeof DAYS)[number];
+
+// Mapping for Date.getDay() which returns 0=Sunday, 1=Monday, etc.
+export const DAY_INDEX: Record<Day, number> = {
+  Sunday: 0,
+  Monday: 1,
+  Tuesday: 2,
+  Wednesday: 3,
+  Thursday: 4,
+  Friday: 5,
+  Saturday: 6,
+};
--- a/packages/shared/src/models/index.ts
+++ b/packages/shared/src/models/index.ts
@@ -1,3 +1,4 @@
 export * from './User';
 export * from './CalendarEvent';
 export * from './ChatMessage';
+export * from './Constants';
--- a/packages/shared/src/utils/dateHelpers.ts
+++ b/packages/shared/src/utils/dateHelpers.ts
@@ -0,0 +1,31 @@
+import { Day, DAY_INDEX } from '../models/Constants';
+
+/**
+ * Get a date for a specific weekday relative to today.
+ * @param day - The target day (e.g., "Friday")
+ * @param offset - 1 = next occurrence, 2 = the one after, -1 = last occurrence, etc.
+ * @param hour - Hour of day (0-23)
+ * @param minute - Minute (0-59)
+ */
+export function getDay(day: Day, offset: number, hour: number, minute: number): Date {
+  const today = new Date();
+  const currentDay = today.getDay();
+  const targetDay = DAY_INDEX[day];
+
+  let daysUntil = targetDay - currentDay;
+
+  if (offset > 0) {
+    // Future: if target is today or past, move to next week
+    if (daysUntil <= 0) daysUntil += 7;
+    daysUntil += (offset - 1) * 7;
+  } else if (offset < 0) {
+    // Past: if target is today or future, move to last week
+    if (daysUntil >= 0) daysUntil -= 7;
+    daysUntil += (offset + 1) * 7;
+  }
+
+  const result = new Date(today);
+  result.setDate(today.getDate() + daysUntil);
+  result.setHours(hour, minute, 0, 0);
+  return result;
+}
--- a/packages/shared/src/utils/index.ts
+++ b/packages/shared/src/utils/index.ts
@@ -0,0 +1 @@
+export * from './dateHelpers';