```php
<?php
require_once 'config.php';

// JWT verification middleware
verifyToken();

// GET sales report
if ($_SERVER['REQUEST_METHOD'] === 'GET') {
    $start_date = $_GET['start_date'] ?? date('Y-m-01');
    $end_date = $_GET['end_date'] ?? date('Y-m-t');
    
    // Total sales
    $stmt = $pdo->prepare("SELECT SUM(total_amount) as total_sales FROM orders WHERE created_at BETWEEN ? AND ?");
    $stmt->execute([$start_date, $end_date]);
    $total_sales = $stmt->fetch(PDO::FETCH_ASSOC);
    
    // Top products
    $stmt = $pdo->prepare("
        SELECT p.name, SUM(oi.quantity) as total_sold, SUM(oi.quantity * oi.unit_price) as revenue 
        FROM order_items oi
        JOIN products p ON oi.product_id = p.id
        JOIN orders o ON oi.order_id = o.id
        WHERE o.created_at BETWEEN ? AND ?
        GROUP BY p.id
        ORDER BY total_sold DESC
        LIMIT 5
    ");
    $stmt->execute([$start_date, $end_date]);
    $top_products = $stmt->fetchAll(PDO::FETCH_ASSOC);
    
    // Report data
    $report = array(
        'total_sales' => $total_sales['total_sales'] ?? 0,
        'start_date' => $start_date,
        'end_date' => $end_date,
        'top_products' => $top_products
    );
    
    echo json_encode($report);
}
?>
```

You'll also need to create the database tables. Here's the SQL schema: