<!doctype html>
<meta charset=utf-8>
<title>CSSTransition.effect</title>
<!-- TODO: Add a more specific link for this once it is specified. -->
<link rel="help" href="https://drafts.csswg.org/css-transitions-2/#csstransition">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src='support/helper.js'></script>
<div id="log"></div>
<script>
'use strict';

function singleFrame() {
  return new Promise((resolve, reject) => {
    requestAnimationFrame(resolve);
  });
}

test(t => {
  const div = addDiv(t);
  div.style.left = '0px';

  div.style.transition = 'left 100s';
  getComputedStyle(div).left;
  div.style.left = '100px';

  const transition = div.getAnimations()[0];

  transition.effect = null;

  assert_equals(transition.transitionProperty, 'left');
}, 'After setting a transition\'s effect to null, it still reports the'
   + ' original transition property');

promise_test(async t => {
  const div = addDiv(t);
  div.style.left = '0px';

  div.style.transition = 'left 100s';
  getComputedStyle(div).left;
  div.style.left = '100px';

  const transition = div.getAnimations()[0];
  await transition.ready;

  transition.effect = null;
  assert_equals(transition.playState, 'finished');
}, 'After setting a transition\'s effect to null, it becomes finished');

promise_test(async t => {
  const div = addDiv(t);
  div.style.left = '0px';

  div.style.transition = 'left 100s';
  getComputedStyle(div).left;
  div.style.left = '100px';

  const transition = div.getAnimations()[0];
  await transition.ready;

  transition.effect = null;
  assert_equals(getComputedStyle(div).left, '100px');
}, 'After setting a transition\'s effect to null, style is updated');

// This is a regression test for https://crbug.com/964113, where Chromium would
// crash if the running transition's effect was set to null and a new transition
// was started before the running one could finish.
promise_test(async t => {
  const div = addDiv(t);
  div.style.left = '0px';

  div.style.transition = 'left 100s';
  getComputedStyle(div).left;
  div.style.left = '100px';

  assert_equals(div.getAnimations().length, 1);

  const transition = div.getAnimations()[0];
  await transition.ready;

  // Without yielding to the rendering loop, set the current transition's
  // effect to null and start a new transition. This should work correctly.
  transition.effect = null;

  div.style.left = '150px';

  // This will run style update.
  assert_equals(div.getAnimations().length, 1);

  const new_transition = div.getAnimations()[0];
  await new_transition.ready;

  assert_equals(getComputedStyle(div).left, '100px');
}, 'After setting a transition\'s effect to null, a new transition can be started');

// This is a regression test for https://crbug.com/992668, where Chromium would
// crash if the running transition's effect was set to null and the transition
// was interrupted before it could finish due to the null effect.
promise_test(async t => {
  const div = addDiv(t);
  div.style.left = '0px';

  div.style.transition = 'left 100s';
  getComputedStyle(div).left;
  div.style.left = '100px';

  assert_equals(div.getAnimations().length, 1);

  const transition = div.getAnimations()[0];
  await transition.ready;

  // The transition needs to have a non-zero currentTime for the interruption
  // reversal logic to apply.
  while (getComputedStyle(div).left == '0px') {
    await singleFrame();
  }
  assert_not_equals(transition.currentTime, 0);

  // Without yielding to the rendering loop, set the current transition's
  // effect to null and interrupt the transition. This should work correctly.
  transition.effect = null;
  div.style.left = '0px';

  // Yield to the rendering loop. This should not crash.
  await singleFrame();
}, 'After setting a transition\'s effect to null, it should be possible to '
    + 'interrupt that transition');

promise_test(async t => {
  const div = addDiv(t);
  div.style.left = '0px';
  div.style.width = '0px';

  div.style.transition = 'left 100s';
  getComputedStyle(div).left;
  div.style.left = '100px';

  const transition = div.getAnimations()[0];
  await transition.ready;

  transition.currentTime = 50 * MS_PER_SEC;
  transition.effect = new KeyframeEffect(div,
                                         { left: [ '0px' , '100px'] },
                                         20 * MS_PER_SEC);

  assert_equals(transition.playState, 'finished');
}, 'After setting a new keyframe effect with a shorter duration,'
   + ' the transition becomes finished');

promise_test(async t => {
  const div = addDiv(t);
  div.style.left = '0px';
  div.style.width = '0px';

  div.style.transition = 'left 100s';
  getComputedStyle(div).left;
  div.style.left = '100px';

  const transition = div.getAnimations()[0];
  transition.effect = new KeyframeEffect(div,
                                         { marginLeft: [ '0px' , '100px'] },
                                         100 * MS_PER_SEC);
  assert_equals(transition.transitionProperty, 'left');
}, 'After setting a new keyframe effect targeting different properties,'
   + ' the transition continues to report the original transition property');

promise_test(async t => {
  const div = addDiv(t);
  div.style.left = '0px';
  div.style.width = '0px';

  div.style.transition = 'left 100s';
  getComputedStyle(div).left;
  div.style.left = '100px';

  const transition = div.getAnimations()[0];
  assert_true(transition.pending);

  transition.effect = new KeyframeEffect(div,
                                         { marginLeft: [ '0px' , '100px'] },
                                         100 * MS_PER_SEC);
  assert_true(transition.pending);

  // As a sanity check, check that the transition actually exits the
  // pending state.
  await transition.ready;
  assert_false(transition.pending);
}, 'After setting a new keyframe effect on a play-pending transition,'
   + ' the transition remains pending');

test(t => {
  const div = addDiv(t);

  div.style.left = '0px';
  getComputedStyle(div).transitionProperty;
  div.style.transition = 'left 100s';
  div.style.left = '100px';

  const transition = div.getAnimations()[0];
  transition.effect = null;

  assert_equals(transition.transitionProperty, 'left');
}, 'A transition with no effect still returns the original transitionProperty');

test(t => {
  const div = addDiv(t);

  div.style.left = '0px';
  getComputedStyle(div).transitionProperty;
  div.style.transition = 'left 100s';
  div.style.left = '100px';

  const transition = div.getAnimations()[0];

  // Seek to the middle and get the portion.
  transition.currentTime = 50 * MS_PER_SEC;
  const portion = transition.effect.getComputedTiming().progress;

  // Replace the effect but keep the original timing
  transition.effect = new KeyframeEffect(
    div,
    { top: ['200px', '300px', '100px'] },
    transition.effect.getTiming()
  );

  // Reverse the transition
  div.style.left = '0px';
  const reversedTransition = div.getAnimations()[0];

  const expectedDuration = 100 * MS_PER_SEC * portion;
  assert_approx_equals(
    reversedTransition.effect.getComputedTiming().activeDuration,
    expectedDuration,
    1
  );
}, 'A transition with a replaced effect still exhibits the regular transition'
   + ' reversing behavior');

</script>