Fitness App

A cross-platform mobile fitness application with client-server architecture for tracking daily calorie intake, weight, and body measurements with AI-powered feedback, notifications, and subscription monetization.

Project Structure

project-root/
├── backend/                         # Backend services
│   ├── auth-service/                # Authentication & Authorization
│   ├── calorie-service/             # Meal logging & FatSecret integration
│   ├── measurement-service/         # Weight & body measurements
│   ├── chat-service/                # OpenAI chat analysis
│   ├── subscription-service/        # Monetization & billing
│   ├── notification-dispatcher/     # Firebase notifications
│   ├── common-lib/                  # Shared backend utilities
│   ├── docker-compose.yml           # Compose orchestration
│   └── build.gradle.kts
├── mobile/                          # Mobile applications
│   ├── shared/                      # Kotlin Multiplatform shared code
│   ├── androidApp/                  # Android-specific UI & integration
│   ├── iosApp/                      # iOS-specific UI & integration
│   └── features/                    # Feature modules for UI & use-cases
├── infrastructure/                  # Deployment & infrastructure
├── scripts/                         # Utility scripts
└── README.md

Technologies Used

• Backend: Ktor server in Kotlin, exposes REST and WebSocket endpoints
• Client: Kotlin Multiplatform (Android & iOS) using Ktor HTTP client
• Deployment: Dockerized services; Docker Compose
• Push Notifications: Firebase Cloud Messaging
• AI Integration: OpenAI REST API
• Nutrition API: FatSecret REST API
• Database: PostgreSQL
• Logging & Monitoring: Prometheus + Grafana
• CI/CD: GitHub Actions for build, tests, and Docker image publishing

Getting Started

Prerequisites

• JDK 17+
• Docker and Docker Compose
• Android Studio or IntelliJ IDEA

Running the Backend

1. Navigate to the backend directory:

   cd backend

2. Start all backend services using Docker Compose:

   docker-compose up -d

3. Or run a specific service locally for development:

   ./gradlew :backend:auth-service:run

API Endpoints

Authentication

• POST /auth/signup/email - Sign up with email/password
• POST /auth/login/email - Login with email/password
• POST /auth/oauth/google - Login with Google
• POST /auth/oauth/apple - Login with Apple

User Profile

• GET /user/profile - Get user profile
• PUT /user/profile - Update user profile

Meals

• GET /meals?date=YYYY-MM-DD - Get meals for a specific date
• POST /meals - Log a meal
• PUT /meals/{id} - Update a meal
• DELETE /meals/{id} - Delete a meal

Weight & Measurements

• GET /weights?from=DATE&to=DATE - Get weight entries in a date range
• POST /weights - Log weight
• GET /measurements?week=YYYY-WW - Get measurements for a specific week
• POST /measurements - Log measurements

AI Chat

• WS /chat/ws - WebSocket for AI chat
• POST /chat/message - Send a message to AI

Subscriptions

• GET /subscriptions - Get user subscription info
• POST /subscriptions - Purchase a subscription
• DELETE /subscriptions/{id} - Cancel a subscription

Development

Adding a New Service

1. Create a new directory under backend/
2. Add the service to settings.gradle.kts
3. Use the common library for shared utilities
4. Add the service to docker-compose.yml

Testing

Run all tests with:

./gradlew test

License

This project is licensed under the MIT License - see the LICENSE file for details.