const BASE_ORIGIN = "http://example.com";
const URI =
  BASE_ORIGIN +
  "/browser/browser/components/contextualidentity/test/browser/empty_file.html";

// Opens `uri' in a new tab with the provided userContextId and focuses it.
// Returns the newly opened tab and browser.
async function openTabInUserContext(uri, userContextId) {
  // open the tab in the correct userContextId
  let tab = BrowserTestUtils.addTab(gBrowser, uri, { userContextId });

  // select tab and make sure its browser is focused
  gBrowser.selectedTab = tab;
  tab.ownerGlobal.focus();

  let browser = gBrowser.getBrowserForTab(tab);
  await BrowserTestUtils.browserLoaded(browser);
  return { tab, browser };
}

async function runTestForReceiver(receiver) {
  let channelName = "contextualidentity-broadcastchannel";

  // reflect the received message on title
  await SpecialPowers.spawn(receiver.browser, [channelName], function (name) {
    content.window.testPromise = new content.window.Promise(resolve => {
      content.window.bc = new content.window.BroadcastChannel(name);
      content.window.bc.onmessage = function (e) {
        content.document.title += e.data;
        resolve();
      };
    });
  });

  let sender1 = await openTabInUserContext(URI, 1);
  let sender2 = await openTabInUserContext(URI, 2);
  sender1.message = "Message from user context #1";
  sender2.message = "Message from user context #2";

  // send a message from a tab in different user context first
  // then send a message from a tab in the same user context
  for (let sender of [sender1, sender2]) {
    await SpecialPowers.spawn(
      sender.browser,
      [{ name: channelName, message: sender.message }],
      function (opts) {
        let bc = new content.window.BroadcastChannel(opts.name);
        bc.postMessage(opts.message);
      }
    );
  }

  // Since sender1 sends before sender2, if the title is exactly
  // sender2's message, sender1's message must've been blocked
  await SpecialPowers.spawn(
    receiver.browser,
    [sender2.message],
    async function (message) {
      await content.window.testPromise.then(function () {
        is(
          content.document.title,
          message,
          "should only receive messages from the same user context"
        );
      });
    }
  );

  gBrowser.removeTab(sender1.tab);
  gBrowser.removeTab(sender2.tab);
}

add_setup(async function () {
  // make sure userContext is enabled.
  await SpecialPowers.pushPrefEnv({
    set: [["privacy.userContext.enabled", true]],
  });
});

add_task(async function test() {
  info("Checking broadcast channel with browser tab receiver");
  let receiver = await openTabInUserContext(URI, 2);
  await runTestForReceiver(receiver);
  gBrowser.removeTab(receiver.tab);
});