<!DOCTYPE html>

<head>
  <title>Cobalt freeze state visibility test</title>
  <script src='black_box_js_test_utils.js'></script>
</head>

<body>
  <h1>
    <span>ID element</span>
  </h1>
  <script>
    // In started mode, visibility should be "visible" and window/document
    // should have focus.
    assertEqual("visible", document.visibilityState);
    assertTrue(document.hasFocus());

    let freezeStateVerified = false;
    // Success callback for verifying visibility and focus in freeze.
    function intoFreezeCallback() {
      freezeStateVerified = true;
    }

    // Success callback for verifying visibility and focus after freeze in
    // started.
    function outOfFreezeCallback() {
      if (freezeStateVerified){
        onEndTest();
      } else {
        // By now, it is in Started state and Freeze state behavior
        // verification will never succeed.
        notReached();
      }
    }

    function verifyVisibilityAndFocusInterval(shouldBeVisible, shouldHaveFocus) {
      visibility_str = shouldBeVisible ? "visible" : "hidden";
      if (document.hasFocus() === shouldHaveFocus && document.visibilityState === visibility_str) {
        return true;
      }
    }

    // Post periodic timer to check desired visibility and focus settings.
    function verifyVisibilityAndFocus(shouldBeVisible, shouldHaveFocus, successCallback) {
      if (verifyVisibilityAndFocusInterval(shouldBeVisible, shouldHaveFocus)) {
        successCallback();
        return true;
      }
      time_elapsed = 0;
      set_interval_id = setInterval(() => {
        if (verifyVisibilityAndFocusInterval(shouldBeVisible, shouldHaveFocus)){
          successCallback()
          clearInterval(set_interval_id);
        }else {
          if (time_elapsed > EFFECT_AFTER_VISIBILITY_CHANGE_TIMEOUT_SECONDS){
            console.log("Waiting for visibilityState and focus change timed out")
            notReached();
          }
          time_elapsed += 0.1;
        }
      }, 50);
    }

    // Wait for visibility change to verify visibilityState and focus status.
    let visibilityChangeCalledBefore = false;
    function handleVisibilityChange() {
      if (!visibilityChangeCalledBefore) {
        verifyVisibilityAndFocus(false, false, intoFreezeCallback);
        visibilityChangeCalledBefore = true;
      } else {
        verifyVisibilityAndFocus(true, true, outOfFreezeCallback);
      }
    }
    document.addEventListener("visibilitychange", handleVisibilityChange);
    setupFinished();
  </script>
</body>