# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Project Overview

**CalChat** is a calendar mobile app with AI support. The core concept is creating calendar events through a chat interface with an AI chatbot (Claude). Users can add, edit, and delete events via natural language conversation.

This is a fullstack TypeScript monorepo with npm workspaces.

## Commands

### Root (monorepo)
```bash
npm install          # Install all dependencies for all workspaces
```

### Client (apps/client) - Expo React Native app
```bash
npm run start -w @caldav/client        # Start Expo dev server
npm run android -w @caldav/client      # Start on Android
npm run ios -w @caldav/client          # Start on iOS
npm run web -w @caldav/client          # Start web version
npm run lint -w @caldav/client         # Run ESLint
```

### Server (apps/server) - Express.js backend
```bash
npm run dev -w @caldav/server          # Start dev server with hot reload (tsx watch)
npm run build -w @caldav/server        # Compile TypeScript
npm run start -w @caldav/server        # Run compiled server (port 3000)
```

## Technology Stack

| Area | Technology | Purpose |
|------|------------|---------|
| Frontend | React Native | Mobile UI Framework |
| | Expo | Development platform |
| | Expo-Router | File-based routing |
| | NativeWind | Tailwind CSS for React Native |
| Backend | Express.js | Web framework |
| | MongoDB | Database |
| | Mongoose | ODM |
| | Claude (Anthropic) | AI/LLM for chat |
| | JWT | Authentication |
| Planned | iCalendar | Event export/import |

## Architecture

### Workspace Structure
```
apps/client      - @caldav/client - Expo React Native app
apps/server      - @caldav/server - Express.js backend
packages/shared  - @caldav/shared - Shared TypeScript types and models
```

### Frontend Architecture (apps/client)

**Screens** (`src/app/`): Login, Register, Calendar, Chat, Event Detail, Notes - file-based routing via Expo-Router

**Services**: API Client for HTTP requests, plus AuthService, EventService, ChatService for domain logic

**Components**: Reusable UI (EventCard, ChatBubble, EventConfirmDialog, MonthSelector)

**Stores**: AuthStore (user + token), EventsStore (calendar events)

### Backend Architecture (apps/server)

```
src/
├── app.ts                    # Entry point, DI setup, Express config
├── controllers/              # Request handlers
│   ├── AuthController.ts     # login(), register(), refresh(), logout()
│   ├── ChatController.ts     # sendMessage(), confirmEvent(), rejectEvent(), getConversations(), getConversation()
│   └── EventController.ts    # create(), getById(), getAll(), getByDateRange(), update(), delete()
├── middleware/
│   └── AuthMiddleware.ts     # authenticate() - JWT validation
├── routes/                   # API endpoint definitions
│   ├── index.ts              # Combines all routes under /api
│   ├── auth.routes.ts        # /api/auth/*
│   ├── chat.routes.ts        # /api/chat/* (protected)
│   └── event.routes.ts       # /api/events/* (protected)
├── services/                 # Business logic
│   ├── interfaces/           # DB-agnostic interfaces (for dependency injection)
│   │   ├── AIProvider.ts     # processMessage()
│   │   ├── UserRepository.ts # + CreateUserData (server-internal DTO)
│   │   ├── EventRepository.ts
│   │   └── ChatRepository.ts
│   ├── AuthService.ts
│   ├── ChatService.ts
│   └── EventService.ts
├── repositories/             # Data access (DB-specific implementations)
│   ├── index.ts              # Re-exports from ./mongo
│   └── mongo/                # MongoDB implementation
│       ├── models/           # Mongoose schemas
│       │   ├── UserModel.ts
│       │   ├── EventModel.ts
│       │   └── ChatModel.ts
│       ├── MongoUserRepository.ts
│       ├── MongoEventRepository.ts
│       └── MongoChatRepository.ts
├── ai/
│   └── ClaudeAdapter.ts      # Implements AIProvider
└── utils/
    ├── jwt.ts                # signToken(), verifyToken()
    └── password.ts           # hash(), compare()
```

**API Endpoints:**
- `POST /api/auth/login` - User login
- `POST /api/auth/register` - User registration
- `POST /api/auth/refresh` - Refresh JWT token
- `POST /api/auth/logout` - User logout
- `GET /api/events` - Get all events (protected)
- `GET /api/events/range` - Get events by date range (protected)
- `GET /api/events/:id` - Get single event (protected)
- `POST /api/events` - Create event (protected)
- `PUT /api/events/:id` - Update event (protected)
- `DELETE /api/events/:id` - Delete event (protected)
- `POST /api/chat/message` - Send message to AI (protected)
- `POST /api/chat/confirm/:conversationId/:messageId` - Confirm proposed event (protected)
- `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)
- `GET /health` - Health check

### Shared Package (packages/shared)

```
src/
├── index.ts
└── models/
    ├── index.ts
    ├── User.ts           # User, CreateUserDTO, LoginDTO, AuthResponse
    ├── CalendarEvent.ts  # CalendarEvent, CreateEventDTO, UpdateEventDTO
    └── ChatMessage.ts    # ChatMessage, Conversation, SendMessageDTO, CreateMessageDTO,
                          # GetMessagesOptions, ChatResponse, ConversationSummary
```

**Key Types:**
- `User`: id, email, displayName, passwordHash?, createdAt?, updatedAt?
- `CalendarEvent`: id, userId, title, description?, startTime, endTime, note?, isRecurring?, recurrenceRule?
- `ChatMessage`: id, conversationId, sender ('user' | 'assistant'), content, proposedEvent?
- `Conversation`: id, userId, createdAt?, updatedAt? (messages loaded separately via lazy loading)
- `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)

### Database Abstraction

The repository pattern allows swapping databases:
- **Interfaces** (`services/interfaces/`) are DB-agnostic
- **Implementations** (`repositories/mongo/`) are DB-specific
- To add MySQL: create `repositories/mysql/` with TypeORM entities

## MVP Feature Scope

### Must-Have
- Chat interface with AI assistant (text input) for event management
- Calendar overview
- Manual event CRUD (without AI)
- View completed events
- Simple reminders
- One note per event
- Recurring events

### Nice-to-Have
- iCalendar import/export
- Multiple calendars
- CalDAV synchronization with external services

## Current Implementation Status

**Backend:** Skeleton complete - all files exist with `throw new Error('Not implemented')` placeholders. Ready for step-by-step implementation.

**Shared:** Types and DTOs defined and exported.

**Frontend:** Calendar screen partially implemented, Chat screen exists but not connected to backend.

## Documentation

Detailed architecture diagrams are in `docs/`:
- `technisches_brainstorm.tex` - Technical concept document (German)
- `architecture-class-diagram.puml` - Backend class diagram
- `frontend-class-diagram.puml` - Frontend class diagram
- `component-diagram.puml` - System component overview