In terms of SEO and programming efficiency, what are the advantages and disadvantages of using a single index.php file for routing versus separate PHP files for each page?

Using a single index.php file for routing can make the codebase more concise and easier to manage, as all routing logic is centralized. However, it can also lead to a bloated file with multiple conditional statements for different routes. On the other hand, using separate PHP files for each page can make the code more modular and organized, but it may require more effort to maintain and update multiple files.

// Single index.php file for routing

$route = $_GET['route'] ?? 'home';

switch ($route) {
    case 'home':
        include 'pages/home.php';
        break;
    case 'about':
        include 'pages/about.php';
        break;
    case 'contact':
        include 'pages/contact.php';
        break;
    default:
        include 'pages/not_found.php';
        break;
}