<!--
@license
Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
Code distributed by Google as part of the polymer project is also
subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
-->

<link rel="import" href="../../polymer/polymer.html">
<link rel="import" href="../neon-shared-element-animation-behavior.html">
<link rel="import" href="../web-animations.html">

<!--
`<reverse-ripple-animation>` scales and transform an element such that it appears to ripple down from this element, to either
a shared element, or a screen position.

If using as a shared element animation in `<neon-animated-pages>`, use this animation in an `exit`
animation in the source page and in an `entry` animation in the destination page. Also, define the
reverse-ripple elements in the `sharedElements` property (not a configuration property, see
`Polymer.NeonSharedElementAnimatableBehavior`).
If using a screen position, define the `gesture` property.
Configuration:
```
{
  name: 'reverse-ripple-animation`.
  id: <shared-element-id>, /* set this or gesture */
  gesture: {x: <page-x>, y: <page-y>}, /* set this or id */
  timing: <animation-timing>,
  toPage: <node>, /* define for the destination page */
  fromPage: <node>, /* define for the source page */
}
```
-->

<script>
  Polymer({
    is: 'reverse-ripple-animation',

    behaviors: [
      Polymer.NeonSharedElementAnimationBehavior
    ],

    configure: function(config) {
      var shared = this.findSharedElements(config);
      if (!shared) {
        return null;
      }

      var translateX, translateY;
      var fromRect = shared.from.getBoundingClientRect();
      if (config.gesture) {
        translateX = config.gesture.x - (fromRect.left + (fromRect.width / 2));
        translateY = config.gesture.y - (fromRect.top + (fromRect.height / 2));
      } else {
        var toRect = shared.to.getBoundingClientRect();
        translateX = (toRect.left + (toRect.width / 2)) - (fromRect.left + (fromRect.width / 2));
        translateY = (toRect.top + (toRect.height / 2)) - (fromRect.top + (fromRect.height / 2));
      }
      var translate = 'translate(' + translateX + 'px,' + translateY + 'px)';

      var size = Math.max(fromRect.width + Math.abs(translateX) * 2, fromRect.height + Math.abs(translateY) * 2);
      var diameter = Math.sqrt(2 * size * size);
      var scaleX = diameter / fromRect.width;
      var scaleY = diameter / fromRect.height;
      var scale = 'scale(' + scaleX + ',' + scaleY + ')';

      this._effect = new KeyframeEffect(shared.from, [
        {'transform': translate + ' ' + scale},
        {'transform': translate + ' scale(0)'}
      ], this.timingFromConfig(config));

      this.setPrefixedProperty(shared.from, 'transformOrigin', '50% 50%');
      shared.from.style.borderRadius = '50%';

      return this._effect;
    },

    complete: function() {
      if (this.sharedElements) {
        this.setPrefixedProperty(this.sharedElements.from, 'transformOrigin', '');
        this.sharedElements.from.style.borderRadius = '';
      }
    }
  });
</script>