AlertNet

AlertNet is a decentralized, offline-first Android communication application designed to keep users connected when traditional cellular or Wi-Fi networks fail or are unavailable. It leverages peer-to-peer (P2P) mesh networking through Bluetooth Low Energy (BLE) and Wi-Fi Direct to enable text messaging, voice notes, file sharing, and location tracking entirely offline.

🚀 Features

• Offline Mesh Networking: Robust custom mesh architecture that dynamically routes messages across multiple hops (peers) using both BLE and Wi-Fi Direct.
• Peer-to-Peer Messaging: Send and receive secure text messages without an internet connection.
• Media & File Transfer: Share voice recordings and files directly with nearby peers.
• Offline Mapping & Location Sharing: View peers on an offline map using MapLibre and share your GPS coordinates securely. Includes granular location privacy settings.
• Background Services: Persistent mesh connectivity and location updates powered by optimized Android Foreground Services.
• Security & Encryption: Built-in cryptographic components for secure key management and encrypted peer-to-peer communication.
• Modern UI: A clean, responsive interface built entirely with Jetpack Compose, following Material 3 design guidelines.

🛠 Tech Stack

• Language: Kotlin
• UI Framework: Jetpack Compose (Material 3)
• Architecture: MVVM / MVI with Jetpack ViewModels and Kotlin Coroutines/Flows
• Networking: Custom P2P Mesh (Wi-Fi Direct / BLE APIs)
• Local Storage: SQLite (via standard queries) & Jetpack DataStore (Preferences)
• Mapping: MapLibre GL Android SDK for offline vector maps
• Location: Google Play Services Location SDK
• Concurrency: Kotlin Coroutines

📂 Project Structure

• db/: SQLite database helpers, mappers, and queries for storing messages, peers, and network state.
• media/: Managers for voice recording and playback capabilities.
• mesh/: Core mesh networking logic, including peer discovery, message routing, deduplication, and acknowledgment tracking.
• model/: Data classes and domain models.
• security/: Cryptographic utilities and key management.
• service/: Android Foreground Services for maintaining background mesh connections and location tracking.
• transfer/: File storage and transfer managers for handling media over the mesh.
• transport/: Abstraction layers for BLE and Wi-Fi Direct connections, managing underlying connection events and data streams.
• ui/: Jetpack Compose UI layer organized by screens (ChatScreen, MeshMapScreen, PeersScreen, etc.), components, and viewmodels.

⚙️ Getting Started

Prerequisites

• Android Studio (Latest stable version recommended)
• Android SDK Platform 36 (targetSdk 36)
• Min SDK 26 (Android 8.0 Oreo)

Installation

1. Clone the repository:

   git clone https://github.com/PankajGupta-dev/AlertNet.git

2. Open the project in Android Studio.
3. Sync the project with Gradle files.
4. Build and run on a physical Android device. (Note: Emulators generally do not support Wi-Fi Direct or BLE testing).

🔒 Permissions

The app requires the following key permissions to function properly:

• BLUETOOTH, BLUETOOTH_ADMIN, BLUETOOTH_ADVERTISE, BLUETOOTH_CONNECT, BLUETOOTH_SCAN
• ACCESS_WIFI_STATE, CHANGE_WIFI_STATE, ACCESS_NETWORK_STATE, CHANGE_NETWORK_STATE, NEARBY_WIFI_DEVICES
• ACCESS_FINE_LOCATION, ACCESS_COARSE_LOCATION, ACCESS_BACKGROUND_LOCATION
• RECORD_AUDIO

Ensure these permissions are granted upon the first launch for the mesh network to initialize correctly.

🤝 Contributing

Contributions, issues, and feature requests are welcome! Feel free to check the issues page.

📄 License

Distributed under the MIT License. See LICENSE for more information.