<!DOCTYPE html>
<meta charset=utf-8>
<title>Pausing an animation</title>
<link rel="help"
  href="https://drafts.csswg.org/web-animations/#pausing-an-animation-section">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/web-animations/testcommon.js"></script>
<script src="testcommon.js"></script>
<style>
.scroller {
  overflow: auto;
  height: 100px;
  width: 100px;
  will-change: transform;
}

.contents {
  height: 1000px;
  width: 100%;
}
</style>
<body>
<script>
'use strict';

promise_test(async t => {
  const animation = createScrollLinkedAnimation(t);
  animation.play();
  await animation.ready;

  const startTimeBeforePausing = animation.startTime;

  animation.pause();
  assert_percents_equal(animation.startTime, startTimeBeforePausing,
                        'The start time does not change when pausing-pending');

  await animation.ready;

  assert_equals(animation.startTime, null,
                'The start time is unresolved when paused');
}, 'Pausing clears the start time');

promise_test(async t => {
  const animation = createScrollLinkedAnimation(t);
  animation.play();
  const promise = animation.ready;
  animation.pause();

  const promiseResult = await promise;

  assert_equals(promiseResult, animation);
  assert_equals(animation.ready, promise);
  assert_false(animation.pending, 'No longer pause-pending');
}, 'A pending ready promise should be resolved and not replaced when the'
   + ' animation is paused');

promise_test(async t => {
  const animation = createScrollLinkedAnimation(t);
  animation.play();
  // Let animation start roughly half-way through
  animation.currentTime = CSSNumericValue.parse("50%");
  await animation.ready;

  // Go pause-pending and also set a pending playback rate
  animation.pause();
  animation.updatePlaybackRate(0.5);

  await animation.ready;
  // If the current time was updated using the new playback rate it will jump
  // back to 25% but if we correctly used the old playback rate the current time
  // will be > 50%.
  assert_percents_equal(animation.currentTime, 50);
}, 'A pause-pending animation maintains the current time when applying a'
   + ' pending playback rate');

promise_test(async t => {
  // This test does not cover a specific step in the algorithm but serves as a
  // high-level sanity check that pausing does, in fact, freeze the current
  // time.
  const animation = createScrollLinkedAnimation(t);
  const scroller = animation.timeline.source;
  const maxScroll = scroller.scrollHeight - scroller.clientHeight;
  animation.play();
  await animation.ready;

  animation.pause();
  await animation.ready;

  const currentTimeAfterPausing = animation.currentTime;

  scroller.scrollTop = 0.2 * maxScroll;
  await waitForNextFrame();
  assert_percents_equal(animation.timeline.currentTime, 20,
                        'Sanity check timeline time changed');

  assert_percents_equal(animation.currentTime, currentTimeAfterPausing,
                        'Animation.currentTime is unchanged after pausing');
}, 'The animation\'s current time remains fixed after pausing');

promise_test(async t => {
  const animation = createScrollLinkedAnimation(t);
  animation.play();

  const originalReadyPromise = animation.ready;
  animation.cancel();
  assert_equals(animation.startTime, null);
  assert_equals(animation.currentTime, null);

  const readyPromise = animation.ready;
  assert_not_equals(originalReadyPromise, readyPromise,
                    'Canceling an animation should create a new ready promise');

  animation.pause();
  assert_equals(animation.playState, 'paused',
                'Pausing a canceled animation should update the play state');
  assert_true(animation.pending, 'animation should be pause-pending');
  await animation.ready;
  assert_false(animation.pending,
               'animation should no longer be pause-pending');
  assert_equals(animation.startTime, null, 'start time should be unresolved');
  assert_percents_equal(animation.currentTime, 0,
                        'current time should be set to zero');
}, 'Pausing a canceled animation sets the current time');

promise_test(async t => {
  const animation = createScrollLinkedAnimation(t);
  const scroller = animation.timeline.source;
  // Make the scroll timeline inactive.
  scroller.style.overflow = 'visible';
  scroller.scrollTop;
  // Wait for new animation frame which allows the timeline to compute new
  // current time.
  await waitForNextFrame();
  assert_equals(animation.timeline.currentTime, null,
                'Sanity check the timeline is inactive.');
  // Pause the animation when the timeline is inactive.
  animation.pause();
  assert_equals(animation.currentTime, null,
                'The current time is null when the timeline is inactive.');
  assert_equals(animation.startTime, null,
                        'The start time is null in Pending state.');
  await waitForNextFrame();
  assert_true(animation.pending,
      'Animation has pause pending task while the timeline is inactive.');
  assert_equals(animation.playState, 'paused',
                `State is 'paused' in Pending state.`);
}, `Pause pending task doesn't run when the timeline is inactive.`);

promise_test(async t => {
  const animation = createScrollLinkedAnimation(t);
  const scroller = animation.timeline.source;
  const maxScroll = scroller.scrollHeight - scroller.clientHeight;
  scroller.scrollTop = 0.2 * maxScroll;
  // Make the scroll timeline inactive.
  scroller.style.overflow = 'visible';
  scroller.scrollTop;
  // Wait for new animation frame which allows the timeline to compute new
  // current time.
  await waitForNextFrame();
  assert_equals(animation.timeline.currentTime, null,
                'Sanity check the timeline is inactive.');
  // Play the animation when the timeline is inactive.
  animation.pause();

  // Make the scroll timeline active.
  scroller.style.overflow = 'auto';
  await animation.ready;
  // Ready promise is resolved as a result of the timeline becoming active.
  assert_percents_equal(animation.currentTime, 20,
      'Animation current time is resolved when the animation is ready.');
  assert_equals(animation.startTime, null,
      'Animation start time is unresolved when the animation is ready.');
}, 'Animation start and current times are correct if scroll timeline is ' +
   'activated after animation.pause call.');

</script>
</body>
