# Axion Backend API

Backend server for the Axion HR/Payroll System with SQLite database.

## Features

- SQLite database with comprehensive schema
- RESTful API endpoints
- JWT authentication
- Role-based access control
- CORS enabled for frontend integration

## Database Schema

The database includes tables for:
- Users (authentication)
- Employees (extended employee info)
- Timecards
- Shifts (scheduling)
- Disciplinary Actions
- Receipts/Invoices
- Payroll Runs
- Payroll Line Items
- Audit Logs
- Performance Reviews
- Documents

## Setup

### 1. Install Dependencies

```bash
cd server
npm install
```

### 2. Initialize Database

```bash
npm run init-db
```

This will:
- Create the database file at `server/data/axion.db`
- Create all tables
- Insert default users (admin, hr, payroll, manager, employee)

### 3. Configure Environment

Create a `.env` file:

```bash
cp .env.example .env
```

Edit `.env` and set:
- `PORT` - Server port (default: 3001)
- `JWT_SECRET` - Secret key for JWT tokens (change in production!)

### 4. Start Server

Development mode (with auto-reload):
```bash
npm run dev
```

Production mode:
```bash
npm start
```

The server will run on `http://localhost:3001`

## API Endpoints

### Authentication

- `POST /api/auth/login` - Login with email/password
- `GET /api/auth/me` - Get current user info

### Users

- `GET /api/users` - Get all users (admin/hr only)
- `GET /api/users/:id` - Get user by ID
- `POST /api/users` - Create user (admin only)
- `PUT /api/users/:id` - Update user (admin/hr only)
- `DELETE /api/users/:id` - Delete user (admin only)

### Receipts

- `GET /api/receipts` - Get receipts (filtered by user)
- `GET /api/receipts/:id` - Get receipt by ID
- `POST /api/receipts` - Create receipt (from OCR)
- `PUT /api/receipts/:id` - Update receipt
- `DELETE /api/receipts/:id` - Delete receipt

### Timecards

- `GET /api/timecards` - Get timecards
- `POST /api/timecards` - Create timecard
- `PATCH /api/timecards/:id/status` - Update timecard status

## Default Users

After initialization, these users are available:

| Email | Password | Role |
|-------|----------|------|
| admin@company.com | admin123 | admin |
| hr@company.com | hr123 | hr |
| payroll@company.com | payroll123 | payroll |
| manager@company.com | manager123 | manager |
| employee@company.com | employee123 | employee |

## Database Location

The SQLite database file is stored at:
```
server/data/axion.db
```

This file is gitignored. To backup, copy this file.

## Development

### Database Migrations

To add new tables or modify schema:
1. Update `src/database/schema.sql`
2. Run `npm run init-db` (this will recreate the database)

For production, use proper migration tools.

### Adding New Routes

1. Create route file in `src/routes/`
2. Import and use in `src/server.js`

Example:
```javascript
import newRoutes from './routes/new.js';
app.use('/api/new', newRoutes);
```

## Production Considerations

1. **Change JWT_SECRET** - Use a strong, random secret
2. **Use PostgreSQL/MySQL** - SQLite is fine for development, but use a proper database for production
3. **Add rate limiting** - Prevent abuse
4. **Enable HTTPS** - Use reverse proxy (nginx) with SSL
5. **Database backups** - Set up regular backups
6. **Environment variables** - Never commit `.env` file

## Frontend Integration

Update your frontend to use the API:

```javascript
const API_URL = 'http://localhost:3001/api';

// Login
const response = await fetch(`${API_URL}/auth/login`, {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ email, password })
});

const { token, user } = await response.json();
localStorage.setItem('token', token);

// Authenticated requests
const usersResponse = await fetch(`${API_URL}/users`, {
  headers: {
    'Authorization': `Bearer ${token}`
  }
});
```

## Troubleshooting

### Database locked error
- SQLite uses WAL mode for better concurrency
- If issues persist, check file permissions

### Port already in use
- Change PORT in `.env`
- Or kill the process using port 3001

### Module not found
- Run `npm install` again
- Check Node.js version (requires Node 18+)