Fluentify Backend

AI-powered language learning platform backend built with Node.js, Express, and PostgreSQL.

🚀 Quick Start with Docker

Prerequisites

• Docker Desktop installed and running

Setup

1. Clone the repository

   git clone <repository-url>
   cd Backend

2. Start the application

   docker-compose up --build

3. Access the application

   • Backend API: http://localhost:5000
   • Health Check: http://localhost:5000/health
   • PostgreSQL: localhost:5432

That's it! The database will be automatically initialized with all tables.

📝 Environment Variables

All configuration is in the .env file:

DATABASE_URL=postgresql://postgres:postgres@postgres:5432/fluentify
PORT=5000
NODE_ENV=development
JWT_SECRET=<your-secret>
GEMINI_API_KEY=<your-api-key>

🛠️ Development

Hot Reload

Code changes in the src/ directory are automatically detected and the server restarts.

View Logs

Stop Services

Reset Database

docker-compose down -v
docker-compose up --build

📊 Database

PostgreSQL 16 is used with the following tables:

• learners - User accounts
• admins - Administrator accounts
• learner_preferences - User language preferences
• courses - Generated language courses (with JSONB data)
• unit_progress - Progress tracking for units
• lesson_progress - Progress tracking for lessons
• exercise_attempts - Exercise completion tracking
• user_stats - User XP and statistics

Tables are automatically created on first startup from src/database/01-tables.sql.

🔌 API Endpoints

Authentication

• POST /api/auth/signup/learner - Learner signup
• POST /api/auth/signup/admin - Admin signup
• POST /api/auth/login/learner - Learner login
• POST /api/auth/login/admin - Admin login
• GET /api/auth/profile - Get user profile

Preferences

• POST /api/preferences/learner - Save preferences
• GET /api/preferences/learner - Get preferences
• PUT /api/preferences/learner - Update preferences
• DELETE /api/preferences/learner - Delete preferences

Courses

• POST /api/courses/generate - Generate new course
• GET /api/courses - Get learner's courses
• GET /api/courses/:courseId - Get course details
• GET /api/courses/:courseId/lessons/:lessonId - Get lesson details
• POST /api/courses/:courseId/lessons/:lessonId/complete - Complete lesson

Progress

• GET /api/progress/courses - Get all courses
• GET /api/progress/courses/:courseId - Get course progress
• POST /api/progress/courses/:courseId/units/:unitId/lessons/:lessonId/complete - Mark lesson complete

User Management (Admin Only)

• GET /api/admin/users/learners - Get all learners (with pagination & search)
• GET /api/admin/users/learners/:learnerId - Get learner details with stats
• PUT /api/admin/users/learners/:learnerId - Update learner (name, email)
• PUT /api/admin/users/learners/:learnerId/password - Reset learner password
• DELETE /api/admin/users/learners/:learnerId - Delete learner account
• GET /api/admin/users/learners/:learnerId/courses - Get learner's courses

🧪 Testing

Test Gemini AI Integration

docker exec -it fluentify-backend npm run test-gemini

Access Backend Shell

docker exec -it fluentify-backend sh

Access Database Shell

docker exec -it fluentify-postgres psql -U postgres -d fluentify

# Once inside PostgreSQL shell:
\l              # List all databases
\dt             # List all tables
\d table_name   # Describe a table
SELECT * FROM learners;  # Query data
\q              # Exit

🏗️ Project Structure

Backend/
├── src/
│   ├── config/           # Database configuration
│   ├── controllers/      # Request handlers (auth, courses, progress, userManagement)
│   ├── database/         # SQL schema files
│   ├── middlewares/      # Express middlewares (auth, error handling)
│   ├── repositories/     # Data access layer (data queries)
│   ├── routes/           # API routes (auth, courses, admin)
│   ├── services/         # Business logic (Gemini AI)
│   ├── utils/            # Utilities (JWT, errors, responses)
│   └── server.js         # Main application file
├── docker-compose.yml    # Docker orchestration
├── Dockerfile           # Docker image definition
├── .env                 # Environment variables
└── package.json         # Dependencies

🔧 Tech Stack

• Runtime: Node.js 22
• Framework: Express.js
• Database: PostgreSQL 16
• AI: Google Gemini API
• Authentication: JWT
• Container: Docker & Docker Compose

📚 Features

• 🤖 AI-powered course generation using Google Gemini
• 🔐 JWT-based authentication
• 📊 Progress tracking with XP and streaks
• 🎯 Unit and lesson management
• 📈 User statistics and achievements
• 👥 Admin user management with CRUD operations
• 🔔 Toast notification system for better UX
• 🔄 Hot-reload development environment

🐛 Troubleshooting

Services won't start?

docker-compose logs
docker-compose down
docker-compose build --no-cache
docker-compose up

Port already in use?

Change ports in docker-compose.yml:

ports:
  - "3000:5000"  # Change left side to different port

Database issues?

# Check database logs
docker-compose logs postgres

# Reset database
docker-compose down -v
docker-compose up --build

📄 License

MIT

🤝 Contributing

Pull requests are welcome!