// Add a fetch event listener, which is triggered when a request is incoming. It uses the handleRequest function to handle requests and return responses.
addEventListener('fetch', event => {
    event.respondWith(handleRequest(event.request))
})

function handleRequest(request) {
    // Parse the request URL.
    const url = new URL(request.url)

    // Extract various components of the URL.
    const {
        href, // Full URL
        protocol, // Protocol (e.g., http:)
        hostname, // Host name (e.g., example.com)
        port, // Port (if specified)
        pathname, // Path (e.g., /path)
        search, // Query string (e.g., ?query=123)
        hash // Fragment after the hash sign (e.g., #section)
    } = url

    // Construct the HTML response content.
    const htmlContent = `
        <!DOCTYPE html>
        <html lang="en">
        <head>
            <meta charset="UTF-8">
            <meta name="viewport" content="width=device-width, initial-scale=1.0">
            <title>Request URL Details</title>
        </head>
        <body>
            <h1>Request URL Details</h1>
            <p><strong>Complete URL:</strong> <a href="${href}">${href}</a></p>
            <p><strong>Protocol:</strong> ${protocol}</p>
            <p><strong>Hostname:</strong> ${hostname}</p>
            ${port ? `<p><strong>Port:</strong> ${port}</p>` : ''}
            <p><strong>Pathname:</strong> ${pathname}</p>
            <p><strong>Search:</strong> ${search}</p>
            ${hash ? `<p><strong>Hash:</strong> ${hash}</p>` : ''}
        </body>
        </html>
    `;

    // Return a response in HTML format.
    return new Response(htmlContent, {
        headers: {
            'Content-Type': 'text/html;charset=UTF-8'
        }
    })
}