# License Key Library

A simple, secure, and flexible licensing library built for Node.js, React, Next.js, and general JavaScript applications.

---

## 🚀 Quick Start

### Installation

```bash
npm install license-lib
```


Environment Setup
Create a .env file at the root with your database and JWT configuration:

env
```JWT_SECRET=your_jwt_secret
DB_HOST=localhost
DB_NAME=license_db
DB_USER_ADMIN=license_admin
DB_PASS_ADMIN=secure_admin_password
DB_USER_READER=license_reader
DB_PASS_READER=secure_reader_password
```


⚙️ Database Setup
Use the provided SQL script to set up your database:

```sql
CREATE DATABASE license_db;

USE license_db;

CREATE TABLE licenses (
  id INT AUTO_INCREMENT PRIMARY KEY,
  user_id VARCHAR(255) NOT NULL,
  hashed_key VARCHAR(255) NOT NULL,
  license_type ENUM('one-time', 'subscription', 'trial') DEFAULT 'one-time',
  tier VARCHAR(50) DEFAULT 'basic',
  valid_until DATETIME DEFAULT NULL,
  created_at DATETIME DEFAULT CURRENT_TIMESTAMP
);

CREATE USER 'license_reader'@'%' IDENTIFIED BY 'secure_reader_password';
GRANT SELECT ON license_db.* TO 'license_reader'@'%';

CREATE USER 'license_admin'@'%' IDENTIFIED BY 'secure_admin_password';
GRANT SELECT, INSERT, UPDATE ON license_db.* TO 'license_admin'@'%';

FLUSH PRIVILEGES;
```

📦 API Endpoints

Generate License

POST /generate-license

Body:

```json
{
  "userId": "user123",
  "licenseType": "subscription",
  "tier": "pro",
  "validUntil": "2024-12-31"
}
```
Response:

```json
Copy code
{
  "licenseKey": "generated.jwt.token"
}
```

Validate License

POST /validate-license

Body:

```json
Copy code
{
  "userId": "user123",
  "licenseKey": "generated.jwt.token"
}
```
Response:

```json
{
  "valid": true
}
```

🎯 Client Integration
Import functions directly from the client module:

```javascript
import { activateLicense, generateFingerprint } from './client';

// Validate license
const valid = await activateLicense(userId, licenseKey);

// Device fingerprinting
const fingerprint = generateFingerprint();
```

⚛️ React Integration
Use the provided React hook and provider:

```jsx
import { LicenseProvider } from './react/LicenseProvider';
import useLicense from './react/useLicense';

const App = () => (
  <LicenseProvider userId="user123" licenseKey="jwt.token">
    <YourApp />
  </LicenseProvider>
);

const YourApp = () => {
  const { isLicensed } = useLicense();
  return <div>{isLicensed ? 'Licensed!' : 'Not Licensed!'}</div>;
};
```

▲ Next.js Integration
Wrap your component easily:

```jsx
import withLicense from './nextjs/withLicense';

const Page = ({ isLicensed }) => (
  <div>{isLicensed ? 'Licensed!' : 'Not Licensed!'}</div>
);

export default withLicense(Page, { userId: 'user123', licenseKey: 'jwt.token' });
```