scar-chat/README.md

# SCAR Chat Application

A cross-platform GUI chat client and server with SSL/TLS encryption and **live video streaming support**, built in C++, Qt, and Java/Kotlin.

## Features

### Server (`chat_server`)
- Listens on TCP port **42317** with TLS/SSL encryption
- Multi-client support with broadcast messaging
- Camera status tracking and relay for all connected clients
- Uses OpenSSL for secure communication
- Linux/cross-platform compatible

### Qt Client (`chat_client_qt`)
- Cross-platform GUI using Qt5/6 Widgets
- TLS/SSL encrypted connection to server
- **Tabbed interface:**
  - **Chat Tab:** Text-based messaging with customization
  - **Video Feeds Tab:** Live camera feeds from all connected users
- **Camera Controls:**
  - Enable/disable camera toggle button
  - Camera selection dropdown
  - Live video feed display (framework for H.264 streaming)
  - Remote user video feed gallery
- **Customizable UI:**
  - Background color selector for all windows
  - Chat text color customization
  - Transparency/opacity slider (0-100%)
- Real-time message sending and receiving
- Linux/cross-platform compatible

### Windows Client (`chat_client_win`)
- Native Win32 GUI client
- Same UI features as Qt client
- Windows-only build

### Android Client
- Full-featured native Android app (Android 7.0+)
- Material Design UI with tabbed interface
- **Features:**
  - Real-time TLS/SSL encrypted chat
  - Camera selection and enable/disable
  - Camera preview from device
  - Remote user status tracking
  - Customizable UI colors and transparency
- Compatible with Android 7.0 (API 24) and above
- Run on physical devices and emulators

## Prerequisites

### Linux / macOS
```bash
# Ubuntu/Debian
sudo apt-get install cmake qtbase5-dev libssl-dev libqt5multimedia5-dev build-essential

# macOS (Homebrew)
brew install cmake qt5 openssl
```

### Windows
- Visual Studio 2019+ or MinGW
- CMake 3.16+
- Qt5/6 SDK with Multimedia module
- OpenSSL for Windows (vcpkg or prebuilt binaries)

## Building

### Linux / macOS

1. **Create and generate certificates:**
   ```bash
   cd certs
   ./generate_certs.sh
   cd ..
   ```

2. **Build the project:**
   ```bash
   mkdir build
   cd build
   cmake ..
   make
   ```

3. **Install (optional):**
   ```bash
   make install
   ```

### Windows
- Visual Studio 2019+ or MinGW
- CMake 3.16+
- Qt5/6 SDK with Multimedia module
- OpenSSL for Windows (vcpkg or prebuilt binaries)

### Android
- Android SDK 24+ (API level 24)
- Android Studio 4.0+ or Gradle 8.1+
- Java JDK 11+

## Building

### Linux / macOS

1. **Create and generate certificates:**
   ```bash
   cd certs
   ./generate_certs.sh
   cd ..
   ```

2. **Build the project:**
   ```bash
   mkdir build
   cd build
   cmake ..
   make
   ```

3. **Install (optional):**
   ```bash
   make install
   ```

### Windows

1. **Generate certificates** (use OpenSSL for Windows or WSL):
   ```bash
   cd certs
   # On Windows, use Git Bash or WSL to run generate_certs.sh
   # Or generate manually using OpenSSL
   cd ..
   ```

2. **Build:**
   ```bash
   mkdir build
   cd build
   cmake ..
   cmake --build . --config Release
   ```

### Android

1. **Using Android Studio:**
   - Open Android Studio
   - File → Open → Select `android_client/` directory
   - Wait for Gradle sync
   - Build → Make Project
   - APK output: `android_client/app/build/outputs/apk/debug/app-debug.apk`

2. **Using Gradle (Command Line):**
   ```bash
   cd android_client
   ./gradlew build
   # For installation on device/emulator
   ./gradlew installDebug
   ```

For detailed Android build instructions, see `android_client/README.md`

   ```bash
   mkdir build
   cd build
   cmake -G "Visual Studio 16 2019" ..
   cmake --build . --config Release
   ```

## Running

### Server

```bash
# Linux / macOS
./build/chat_server certs/server.crt certs/server.key

# Windows
.\build\Release\chat_server.exe certs\server.crt certs\server.key
```

The server will listen on `localhost:42317` and relay:
- Text chat messages
- Camera status updates (enable/disable)
- Video frame data (framework ready for H.264 streaming)

### Qt Client

```bash
# Linux / macOS
./build/chat_client_qt

# Windows (if built on Windows)
.\build\Release\chat_client_qt.exe
```

**Usage Steps:**
1. Enter server host/port (default: localhost:42317)
2. Click "Connect" to establish TLS connection
3. Switch to "Video Feeds" tab
4. Select your camera from the dropdown
5. Check "Enable Camera" to start video
6. Switch to "Chat" tab to send messages

### Android Client

1. **On Physical Device:**
   ```bash
   cd android_client
   ./gradlew installDebug
   ```
   - Or open app manually after building

2. **On Emulator:**
   - Start Android Virtual Device from Android Studio
   ```bash
   cd android_client
   ./gradlew installDebug
   ```

**Usage Steps:**
1. Enter server host (IP address or hostname)
2. Enter server port (default: 42317)
3. Tap "Connect" to establish TLS connection
4. Go to "Video" tab
5. Select camera from dropdown
6. Check "Enable Camera" to start camera
7. Go to "Chat" tab to send/receive messages

5. Check "Enable Camera" to broadcast your video status
6. See all connected users' camera status in the feed gallery
7. Use "Chat" tab for text messaging with customization options

### Windows Client

```bash
# Windows only
.\build\Release\chat_client_win.exe
```

## Customization Features

### Chat Tab
**Background Color**
- Click "BG Color" button to select background color for all windows
- Color choice is applied immediately

**Text Color**
- Click "Text Color" button to select chat text color
- Updates chat display in real-time

**Transparency**
- Use the transparency slider (0-100%) to adjust window opacity
- 0% = fully transparent, 100% = fully opaque

### Video Feeds Tab
**Camera Enable/Disable**
- Toggle "Enable Camera" checkbox to start/stop your camera
- Status is broadcast to all connected users
- Green border indicates active camera, gray indicates disabled

**Camera Selection**
- Choose from available cameras in your system
- Supports multiple camera inputs

**Video Feed Display**
- **Your Camera Feed:** Shows your active camera stream (640x480)
- **Connected Users:** Grid display of all users' video feeds (320x240 each)
- **Status Indicators:** Shows "Online" or "Offline" for each user's camera

## Video Streaming Architecture

The application includes a framework for live video streaming:

1. **Camera Capture:** Qt5 Multimedia module handles camera access
2. **Protocol:** Camera status (enable/disable) sent over TLS
3. **Future Expansion:** 
   - Binary video frame encoding (H.264/VP9)
   - Real-time frame transmission over TLS socket
   - Hardware-accelerated decoding on client side
   - Bandwidth optimization with adaptive bitrate streaming

**Current Implementation:**
- ✅ Camera detection and selection
- ✅ Enable/disable controls
- ✅ Status synchronization across clients
- ⏳ Full H.264 video encoding/decoding (requires additional codec libraries)

## SSL/TLS Certificates

### Generate Self-Signed Certificates

For development and testing:

```bash
cd certs

# Generate private key
openssl genrsa -out server.key 2048

# Generate certificate (valid for 365 days)
openssl req -new -x509 -key server.key -out server.crt -days 365 \
  -subj "/C=US/ST=State/L=City/O=SCAR/CN=localhost"

cd ..
```

**Note:** For production, use certificates signed by a trusted Certificate Authority (CA).

### Ignoring Self-Signed Certificates

The Qt client is configured to ignore self-signed certificate errors during development:
```cpp
socket->ignoreSslErrors();
```

For production, implement proper certificate validation.

## Project Structure

```
scar-chat/
├── CMakeLists.txt          # Top-level CMake configuration
├── README.md               # This file
├── certs/                  # SSL certificates directory
│   └── generate_certs.sh   # Certificate generation script
├── src/
│   ├── server/
│   │   └── server.cpp      # TLS server with camera status relay
│   ├── qt_client/
│   │   └── main.cpp        # Qt GUI client with video streaming
│   └── windows_client/
│       └── main_win.cpp    # Win32 GUI client (Windows-only)
└── build/                  # Build output directory (created after cmake)
    ├── chat_server         # Linux server binary
    └── chat_client_qt      # Linux client binary (179 KB with video support)
```

## Troubleshooting

### "Connection refused" error
- Ensure server is running on the same host/port
- Check firewall settings on port 42317

### SSL/TLS errors
- Verify certificates exist in `certs/` directory
- Regenerate certificates if expired or corrupted
- Ensure certificate and key files are readable

### Qt not found during CMake
```bash
# Set Qt path explicitly
cmake -DQt5_DIR=/path/to/Qt5/lib/cmake/Qt5 ..
```

### OpenSSL not found during CMake
```bash
# Set OpenSSL path explicitly (macOS example)
cmake -DOPENSSL_DIR=/usr/local/opt/openssl ..
```

## Development Notes

- **C++17** standard is required
- **Qt5/6** for cross-platform GUI
- **OpenSSL 1.1+** for TLS/SSL
- Threading used for non-blocking socket operations
- Message protocol: simple newline-delimited UTF-8 text

## Security Considerations

- ✅ Uses TLS 1.2+ for encrypted communication
- ⚠️ Development mode: ignores self-signed certificate errors
- ⚠️ No user authentication implemented
- ⚠️ No message encryption at application level (relies on TLS)

For production use, implement:
- Proper certificate validation
- User authentication and authorization
- Message signing/verification
- Rate limiting and DoS protection
- Video frame encryption (end-to-end)

## Future Enhancements

### Video Streaming
- [ ] H.264/VP9 video codec integration
- [ ] Adaptive bitrate streaming based on network conditions
- [ ] Hardware-accelerated encoding/decoding (NVIDIA NVENC, Intel QuickSync)
- [ ] STUN/TURN for P2P connections (bypass server for bandwidth efficiency)
- [ ] Screen sharing mode
- [ ] Picture-in-picture for local + remote feeds

### Chat Features
- [ ] Message history persistence (database backend)
- [ ] User authentication with username/password
- [ ] Emoji and rich text support
- [ ] File transfer with progress bar
- [ ] Message reactions and threading

### UI/UX
- [ ] Dark mode / light mode themes
- [ ] Resizable video feed windows
- [ ] Drag-and-drop window layout
- [ ] Audio chat (VoIP) integration
- [ ] Settings/preferences dialog

## License

This project is provided as-is for educational and development purposes.