Vortex - Android P2P Chat

A peer-to-peer chat application for Android that mirrors the iOS implementation exactly. Uses WebRTC for direct communication and WebSocket signaling server.

Features

• Real-time P2P messaging using WebRTC data channels
• Same signaling server and TURN/STUN configuration as iOS app
• Automatic reconnection on connection loss
• Room-based chat system
• Cross-platform compatibility with iOS version

Installation

cd /home/botond/AndroidStudioProjects/Vortex
./gradlew installDebug

Usage

1. Launch the app - it will automatically connect to the signaling server
2. Wait for "Connected" status - the status should change from "Connecting" to "Connected"
3. Enter a Room ID (or leave blank for "default") and tap "Join Room"
4. Chat with other users - open the iOS app or another Android instance in the same room
5. Send messages - the "Send" button becomes enabled when P2P connection is established

Architecture

Components

• ChatManager.kt - WebRTC peer connection management, WebSocket signaling, message handling
• MainActivity.kt - Simple UI with status, room controls, message list, and input
• ConnectionStatusAndroid - Connection state enum (DISCONNECTED, CONNECTING, CONNECTED)
• ChatMessage - Data class for individual messages with timestamp and sender info

Network Configuration

• Signaling Server: wss://chat.ballabotond.com
• STUN Servers: Google STUN servers for NAT traversal
• TURN Servers:
  • Primary: chat.ballabotond.com:3478 (UDP/TCP/TLS)
  • Fallback: openrelay.metered.ca (UDP/TCP)

Connection Flow

1. WebSocket connects to signaling server
2. Server sends "connected" message with client ID
3. User joins room via "join_room" message
4. When second user joins, server sends "room_ready" with initiator flag
5. Initiator creates offer and data channel
6. WebRTC negotiation (offer/answer/ICE candidates) via signaling
7. P2P data channel opens for direct messaging

Debugging

Enable verbose logging to see connection details:

adb logcat | grep ChatManager

Key log messages to watch for:

• 🔧 Setting up WebRTC... - WebRTC initialization
• WebSocket opened - waiting for server confirmation - WebSocket connection
• Connected to signaling server with ID: <id> - Successful server connection
• 🎯 Room is ready! Both users connected - Room pairing successful
• 🟢 Data channel: Open! Ready to send messages - P2P connection established
• 📥 Received P2P message: '<message>' - Message received

Testing

1. Single device: Use both Android and iOS apps
2. Multiple devices: Install on different devices, same room ID
3. Network conditions: Test on different networks (WiFi, mobile data)
4. Connection recovery: Kill and restart app to test reconnection

Dependencies

• Stream WebRTC: io.getstream:stream-webrtc-android:1.0.7
• OkHttp: com.squareup.okhttp3:okhttp:4.12.0
• Gson: com.google.code.gson:gson:2.10.1
• Kotlinx Coroutines: org.jetbrains.kotlinx:kotlinx-coroutines-android:1.8.1

Compatibility

• Android API Level: 26+ (Android 8.0)
• Target SDK: 35
• Architecture: ARM64, ARMv7, x86, x86_64
• Cross-platform: Compatible with iOS version using same protocols