/* Any copyright is dedicated to the Public Domain.
   http://creativecommons.org/publicdomain/zero/1.0/ */
/* eslint-disable mozilla/no-arbitrary-setTimeout */

const HISTOGRAM_NAME = "FX_SESSION_RESTORE_SEND_UPDATE_CAUSED_OOM";

/**
 * Test that an OOM in sendAsyncMessage in a framescript will be reported
 * to Telemetry.
 */

add_setup(async function () {
  Services.telemetry.canRecordExtended = true;
});

function frameScript() {
  // Make send[A]syncMessage("SessionStore:update", ...) simulate OOM.
  // Other operations are unaffected.
  let mm = docShell.messageManager;

  let wrap = function (original) {
    return function (name, ...args) {
      if (name != "SessionStore:update") {
        return original(name, ...args);
      }
      throw new Components.Exception(
        "Simulated OOM",
        Cr.NS_ERROR_OUT_OF_MEMORY
      );
    };
  };

  mm.sendAsyncMessage = wrap(mm.sendAsyncMessage.bind(mm));
  mm.sendSyncMessage = wrap(mm.sendSyncMessage.bind(mm));
}

add_task(async function () {
  // Capture original state.
  let snapshot = Services.telemetry.getHistogramById(HISTOGRAM_NAME).snapshot();

  // Open a browser, configure it to cause OOM.
  let newTab = BrowserTestUtils.addTab(gBrowser, "about:robots");
  let browser = newTab.linkedBrowser;
  await ContentTask.spawn(browser, null, frameScript);

  let promiseReported = new Promise(resolve => {
    browser.messageManager.addMessageListener("SessionStore:error", resolve);
  });

  // Attempt to flush. This should fail.
  let promiseFlushed = TabStateFlusher.flush(browser);
  promiseFlushed.then(success => {
    if (success) {
      throw new Error("Flush should have failed");
    }
  });

  // The frame script should report an error.
  await promiseReported;

  // Give us some time to handle that error.
  await new Promise(resolve => setTimeout(resolve, 10));

  // By now, Telemetry should have been updated.
  let snapshot2 = Services.telemetry
    .getHistogramById(HISTOGRAM_NAME)
    .snapshot();
  gBrowser.removeTab(newTab);

  Assert.ok(snapshot2.sum > snapshot.sum);
});

add_task(async function cleanup() {
  Services.telemetry.canRecordExtended = false;
});