let blockingEnabled = true;

chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
  if (message.action === 'toggleBlocking') {
    blockingEnabled = message.enabled;
  }

  if (message.action === 'getBlockingState') {
    sendResponse({ action: 'setBlockingState', enabled: blockingEnabled });
  }
});

chrome.webRequest.onHeadersReceived.addListener(
  function(details) {
    if (!blockingEnabled) {
      return { cancel: false };
    }
    
    // These are Cloudflare's headers, taken from here:
    // https://developers.cloudflare.com/fundamentals/reference/http-headers/
    const cloudflare_headers = [
      'cf-connecting-ip',
      'cf-connecting-ipv6',
      'cf-ew-via',
      'cf-Pseudo-ipv4',
      'cf-ray',
      'cf-ipcountry',
      'cf-visitor',
      'cf-worker'
    ];
    // You might want capture all headers prefixed with "cf-":
    // const cf_header = details.responseHeaders.find(header =>
    //   header.name.toLowerCase().startsWith('cf-')
    // );
    
    const cf_header = details.responseHeaders.find(header =>
      cloudflare_headers.includes(header.name.toLowerCase())
    );

    if (cf_header) {
      console.log('Cloudflare header found:', cf_header);
      
      const query_params = new URLSearchParams({
        name: cf_header.name,
        value: cf_header.value,
        url: details.url
      }).toString();

      /*
       * It would be cool to pass the tab URL in the query params, but how?
       * When accessing chrome.tabs here, the active tab URL is "about:newtab".
       * Because we block the request immediately and the tab URL state doesn't
       * never update to the URL we tried to access. I'd like to pass the URL
       * to the web.archive.org/tab_url_here in blocked.html.
       * Email contact@libroot.org if you know a solution!
       */

      // Redirect to our custom blocked.html page
      const url = chrome.runtime.getURL('blocked.html') + '?' + query_params;
      console.log('Redirecting to blocked page:', url);
      chrome.tabs.update(details.tabId, { url: url });

      // Block the request, reject Cloudflare!
      return { cancel: true };
    }
  },
  { urls: ['<all_urls>'] },
  ['blocking', 'responseHeaders']
);