background.js

; (async function () {

  /*
   * Ignore any pages which were assigned in Multi-Account Containers (MAC)
   */
  const MAC_ADDON_ID = '@testpilot-containers';

  let macAddonEnabled = await (async function () {
    try {
      const macAddonInfo = await browser.management.get(MAC_ADDON_ID);
      return true;
    } catch (e) {
      return false;
    }
  }());

  const onMACAddonEnabledChange = enabled => info => {
    if (info.id !== MAC_ADDON_ID) return;
    macAddonEnabled = enabled;
  };
  browser.management.onInstalled.addListener(onMACAddonEnabledChange(true));
  browser.management.onEnabled.addListener(onMACAddonEnabledChange(true));
  browser.management.onUninstalled.addListener(onMACAddonEnabledChange(false));
  browser.management.onDisabled.addListener(onMACAddonEnabledChange(false));

  const isMACAssigned = async function (url) {
    if (!macAddonEnabled) return false;

    try {
      const assignment = await browser.runtime.sendMessage(MAC_ADDON_ID, {
        method: 'getAssignment',
        url,
      });
      return Boolean(assignment);
    } catch (e) {
      return false;
    }
  };

  /*
   * Check such pages and ask user to chose a container
   */
  /** @type {Map<number, { requestIds: Set<string>, urls: Set<string> }>} */
  const canceledRequests = new Map();

  const cleanCancledRequest = tabId => {
    if (canceledRequests.has(tabId)) {
      canceledRequests.delete(tabId);
    }
  };
  browser.webRequest.onCompleted.addListener(options => {
    cleanCancledRequest(options.tabId);
  }, { urls: ['<all_urls>'], types: ['main_frame'] });

  browser.webRequest.onErrorOccurred.addListener(options => {
    cleanCancledRequest(options.tabId);
  }, { urls: ['<all_urls>'], types: ['main_frame'] });

  const shouldCancelEarly = function (tab, request) {
    const tabId = tab.id;
    const { requestId, url } = request;
    if (!canceledRequests.has(tabId)) {
      canceledRequests.set(tabId, {
        requestIds: new Set([requestId]),
        urls: new Set([url]),
      });
      setTimeout(() => { canceledRequests.delete(tabId); }, 2000);
      return false;
    }
    const tabInfo = canceledRequests.get(tabId);
    const shouldCancel = tabInfo.requestIds.has(requestId) || tabInfo.urls.has(url);
    tabInfo.requestIds.add(requestId);
    tabInfo.urls.add(url);
    return shouldCancel;
  };

  browser.webRequest.onBeforeRequest.addListener(async function containTab(request) {
    const tab = await browser.tabs.get(request.tabId);

    if (request.tabId === -1) return void 0;
    if (tab.incognito) return void 0;

    try {
      await browser.contextualIdentities.get(tab.cookieStoreId);
      return void 0;
    } catch (e) {
      /* we are not contained yet */
    }

    if (await isMACAssigned(request.url)) return void 0;

    if (request && shouldCancelEarly(tab, request)) {
      return { cancel: true };
    }

    const choseUrl = new URL(browser.runtime.getURL('/togo/index.html'));
    choseUrl.searchParams.set('go', request.url);
    await browser.tabs.create({
      url: choseUrl + '',
      active: tab.active,
      index: tab.index,
      windowId: tab.windowId,
    });
    browser.tabs.remove(tab.id);

    return { cancel: true };

  }, { urls: ['<all_urls>'], types: ['main_frame'] }, ['blocking']);

}());