# E-Learning Backend

Backend API for the E-Learning Platform built with Node.js, Express, Prisma, and PostgreSQL.

## 🚀 Features

- **Authentication & Authorization**: JWT-based authentication with role-based access control
- **Course Management**: Create, manage, and publish courses with chapters and lessons
- **Multi-Language Support**: Thai and English content support
- **Quiz System**: Interactive quizzes with multiple attempts and score policies
- **Progress Tracking**: Track student progress and issue certificates
- **File Upload**: Support for video lessons and attachments (MinIO/S3)
- **Caching**: Redis integration for improved performance
- **Security**: Helmet, CORS, rate limiting, and input validation

## 📋 Prerequisites

- Node.js >= 18.0.0
- PostgreSQL >= 14
- Redis (optional, for caching)
- MinIO or S3 (for file storage)

## 🛠️ Installation

1. **Clone the repository**
```bash
git clone <repository-url>
cd e-learning/Backend
```

2. **Install dependencies**
```bash
npm install
```

3. **Setup environment variables**
```bash
cp .env.example .env
# Edit .env with your configuration
```

4. **Start Docker services** (PostgreSQL, Redis, MinIO)
```bash
docker compose up -d
```

5. **Run database migrations**
```bash
npx prisma migrate dev
```

6. **Seed the database**
```bash
npm run prisma:seed
```

7. **Start development server**
```bash
npm run dev
```

The server will start on `http://localhost:4000`

## 📁 Project Structure

```
Backend/
├── prisma/
│   ├── migrations/        # Database migrations
│   ├── schema.prisma      # Database schema
│   └── seed.js           # Database seeding
├── src/
│   ├── config/           # Configuration files
│   │   ├── database.js   # Prisma client
│   │   ├── logger.js     # Winston logger
│   │   └── redis.js      # Redis client
│   ├── controllers/      # Request handlers
│   ├── middleware/       # Express middleware
│   │   ├── auth.js       # Authentication & authorization
│   │   └── errorHandler.js
│   ├── routes/           # Route definitions
│   ├── services/         # Business logic
│   ├── utils/            # Utility functions
│   │   └── jwt.js        # JWT utilities
│   ├── validators/       # Input validation
│   ├── app.js           # Express app setup
│   └── server.js        # Server entry point
├── tests/               # Test files
├── logs/                # Log files
├── .env.example         # Environment variables template
├── package.json
└── README.md
```

## 🔑 Environment Variables

See `.env.example` for all available environment variables.

Key variables:
- `DATABASE_URL`: PostgreSQL connection string
- `JWT_SECRET`: Secret key for JWT tokens
- `REDIS_URL`: Redis connection string
- `S3_ENDPOINT`: MinIO/S3 endpoint
- `CORS_ORIGIN`: Allowed CORS origins

## 🧪 Testing

```bash
# Run all tests
npm test

# Run tests in watch mode
npm run test:watch

# Run tests with coverage
npm test -- --coverage
```

## 📝 API Documentation

### Authentication

- `POST /api/auth/register` - Register new user
- `POST /api/auth/login` - Login user
- `GET /api/auth/me` - Get current user profile
- `POST /api/auth/logout` - Logout user

### Health Check

- `GET /health` - Server health status

## 🔐 Default Credentials

After seeding the database, you can use these credentials:

- **Admin**: `admin` / `admin123`
- **Instructor**: `instructor` / `admin123`
- **Student**: `student` / `admin123`

## 🛠️ Development

```bash
# Start dev server with auto-reload
npm run dev

# Run linter
npm run lint

# Format code
npm run format

# Open Prisma Studio (database GUI)
npm run prisma:studio
```

## 📦 Database Commands

```bash
# Generate Prisma Client
npm run prisma:generate

# Create migration
npx prisma migrate dev --name migration_name

# Apply migrations
npx prisma migrate deploy

# Reset database (development only)
npx prisma migrate reset

# Seed database
npm run prisma:seed
```

## 🚀 Production Deployment

1. Set `NODE_ENV=production`
2. Set strong `JWT_SECRET`
3. Configure production database
4. Run migrations: `npx prisma migrate deploy`
5. Start with PM2: `pm2 start src/server.js`

## 📚 Resources

- [Prisma Documentation](https://www.prisma.io/docs)
- [Express Documentation](https://expressjs.com/)
- [JWT Documentation](https://jwt.io/)

## 📄 License

MIT