<!--
@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">

<script>

  /** @polymerBehavior */
  Polymer.PaperSpinnerBehavior = {

    listeners: {
      'animationend': '__reset',
      'webkitAnimationEnd': '__reset'
    },

    properties: {
      /**
       * Displays the spinner.
       */
      active: {
        type: Boolean,
        value: false,
        reflectToAttribute: true,
        observer: '__activeChanged'
      },

      /**
       * Alternative text content for accessibility support.
       * If alt is present, it will add an aria-label whose content matches alt when active.
       * If alt is not present, it will default to 'loading' as the alt value.
       */
      alt: {
        type: String,
        value: 'loading',
        observer: '__altChanged'
      },

      __coolingDown: {
        type: Boolean,
        value: false
      }
    },

    __computeContainerClasses: function(active, coolingDown) {
      return [
        active || coolingDown ? 'active' : '',
        coolingDown ? 'cooldown' : ''
      ].join(' ');
    },

    __activeChanged: function(active, old) {
      this.__setAriaHidden(!active);
      this.__coolingDown = !active && old;
    },

    __altChanged: function(alt) {
      // user-provided `aria-label` takes precedence over prototype default
      if (alt === this.getPropertyInfo('alt').value) {
        this.alt = this.getAttribute('aria-label') || alt;
      } else {
        this.__setAriaHidden(alt==='');
        this.setAttribute('aria-label', alt);
      }
    },

    __setAriaHidden: function(hidden) {
      var attr = 'aria-hidden';
      if (hidden) {
        this.setAttribute(attr, 'true');
      } else {
        this.removeAttribute(attr);
      }
    },

    __reset: function() {
      this.active = false;
      this.__coolingDown = false;
    }
  };
</script>