Nexia CHAT (Flutter Messenger)

A modern mobile messaging application built with Flutter, providing real-time chat, multimedia sharing, and video calls using Firebase and WebRTC. The project was developed in an academic context with a focus on application architecture, user experience, and basic security considerations.

📸 Application Screenshots

0. Authentication

• User login screen
• User registration screen

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1. Main Screens

• Chat list overview
• Call history screen
• Application settings (general)
• Application settings (languages)

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2. Chat & User Interaction

• Chat conversation interface
• Media preview inside chat
• User profile and details
• User search screen

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3. Calls & File Sharing

• File sharing interface
• Call initiation screen
• Video call

✨ Features

Core Messaging

• Real-time messaging with Firestore
• Message status tracking (sent ✓, delivered ✓✓, read ✓✓)
• File sharing (images, videos, documents, audio)
• User search and contact discovery
• Online / offline user presence
• Unread message counters per conversation
• Message grouping by date
• Local message caching for improved performance

Media & Files

• Send and receive media and documents, including:
  • Images
  • Videos
  • Audio messages
  • Documents
• Media preview directly inside the chat
• Cloud storage powered by Firebase

Communication

• Peer-to-peer video calls via WebRTC
• Voice messaging support
• Optimized communication for mobile networks

User Experience

• Multi-language (English, French, Russian)
• Online presence indicators
• Push notifications for new messages
• Light/Dark theme support

📁 Project Architecture

├── main.dart                 # Application entry point
├── app/
│   ├── data/
│   │   ├── models/           # Data models (User, Message, Chat)
│   │   ├── providers/        # Firebase services
│   │   └── repositories/     # Business logic abstraction
│   ├── modules/
│   │   ├── auth/             # Authentication
│   │   ├── chat/             # Real-time messaging
│   │   ├── call/             # WebRTC video calls
│   │   ├── profile/          # User profile
│   │   └── settings/         # App settings
│   ├── services/             # Global services
│   ├── utils/                # Helpers & constants
│   └── widgets/              # Reusable widgets
└── generated/                # Generated files

🛠️ Tech Stack

Technology	Usage
Flutter (Dart)	Mobile UI development
Firebase Auth	User authentication
Cloud Firestore	Real-time messaging
Firebase Storage	Media file storage
WebRTC	Audio and video calls
Local Cache	Message caching

📚 Getting Started

Prerequisites

• Flutter SDK 3.16 or higher
• Firebase account and project
• Android Studio / VS Code
• Physical device or emulator

Installation

1. Clone the repository

git clone https://github.com/undescoreF/nexia_chat

2. Install dependencies

flutter pub get

3. Firebase Setup(Android)

flutterfire configure

4. Configure environment variables

Create.env file in root:

# Firebase
FIREBASE_API_KEY=your_firebase_api_key_here
FIREBASE_APP_ID=your_firebase_app_id_here
FIREBASE_PROJECT_ID=your_firebase_project_id_here
FIREBASE_MESSAGING_SENDER_ID=your_firebase_messaging_sender_id_here
FIREBASE_STORAGE_BUCKET=your_firebase_storage_bucket_here

# OneSignal
ONESIGNAL_APP_ID=your_onesignal_app_id_here
ONESIGNAL_REST_KEY=your_onesignal_rest_api_key_here
CHANEL_ID=your_onesignal_channel_id_here

# NAT
NAT_USERNAME=your_nat_username_here
NAT_CRED=your_nat_credentials_here

5. Run the application

flutter run

6.🔧 Configuration

Firebase Rules

// Firestore security rules
rules_version = '2';
service cloud.firestore {
  match /databases/{database}/documents {
    match /messages/{chatId}/{message} {
      allow read, write: if request.auth != null 
        && request.auth.uid in resource.data.participants;
    }
  }
}

WebRTC Configuration

Update STUN/TURN servers in lib/app/modules/call/services/webrtc_service.dart:

final configuration = {
  'iceServers': [
    {'urls': 'stun:stun.l.google.com:19302'},
    {
    'urls': 'turn:your.turn.server',
     'username': 'user',
      'credential': 'pass'
      }
  ]
};

🔐 Security Notes

This project integrates basic mobile security practices, including:

• Secure authentication using Firebase
• HTTPS-encrypted communication
• Controlled access through Firebase security rules
• Limited and scoped local caching
• Proper permission handling on Android

Basic security checks were performed on:

• Local cache content
• Firebase configuration
• Network traffic
• Application permissions

This project does not claim full end-to-end encryption and is intended for educational purposes only.

Future Improvements

The app is functional, but there are several planned improvements to enhance performance, usability, and security:

• Enhanced Audio & Video Calls

  • Improve call quality and stability on mobile networks.
  • Refine UI/UX for call screens (in-call controls, participant info, call duration).
  • Add group calling support.

• End-to-End Encryption (E2EE)

  • Implement full encryption for messages and media to ensure privacy.
  • Encrypt video and audio streams during WebRTC calls.
  • Secure encryption key management.

• Advanced Data Security

  • Harden Firebase rules for fine-grained access control.
  • Improve local cache encryption and storage security.

• User Experience Enhancements

  • Add chat reactions and message editing/deletion.
  • Smooth animations for sending/receiving messages and file uploads.
  • Multi-device support (sync across phone and tablet).

• Performance & Scalability

  • Optimize database queries for large message histories.
  • Reduce app startup time and memory usage.

• Analytics & Monitoring

  • Integrate crash reporting and performance monitoring.
  • Track app usage metrics for future optimization.