SGH / COMPONENTS

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<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../neon-animation/neon-animation-runner-behavior.html">
<link rel="import" href="../neon-animation/animations/fade-in-animation.html">
<link rel="import" href="../neon-animation/animations/fade-out-animation.html">
<!--

`<paper-tooltip>` is a label that appears on hover and focus when the user
hovers over an element with the cursor or with the keyboard. It will be centered
to an anchor element specified in the `for` attribute, or, if that doesn't exist,
centered to the parent node containing it.

Example:

    <div style="display:inline-block">
      <button>Click me!</button>
      <paper-tooltip>Tooltip text</paper-tooltip>
    </div>

    <div>
      <button id="btn">Click me!</button>
      <paper-tooltip for="btn">Tooltip text</paper-tooltip>
    </div>

The tooltip can be positioned on the top|bottom|left|right of the anchor using
the `position` attribute. The default position is bottom.

    <paper-tooltip for="btn" position="left">Tooltip text</paper-tooltip>
    <paper-tooltip for="btn" position="top">Tooltip text</paper-tooltip>

### Styling

The following custom properties and mixins are available for styling:

Custom property | Description | Default
----------------|-------------|----------
`--paper-tooltip-background` | The background color of the tooltip | `#616161`
`--paper-tooltip-opacity` | The opacity of the tooltip | `0.9`
`--paper-tooltip-text-color` | The text color of the tooltip | `white`
`--paper-tooltip` | Mixin applied to the tooltip | `{}`

@group Paper Elements
@element paper-tooltip
@demo demo/index.html
-->

<dom-module id="paper-tooltip">
  <template>
    <style>
      :host {
        display: block;
        position: absolute;
        outline: none;
        z-index: 1002;
      }

      #tooltip {
        display: block;
        outline: none;
        @apply(--paper-font-common-base);
        font-size: 10px;

        background-color: var(--paper-tooltip-background, #616161);
        opacity: var(--paper-tooltip-opacity, 0.9);
        color: var(--paper-tooltip-text-color, white);

        padding: 8px;
        border-radius: 2px;

        @apply(--paper-tooltip);
      }

      /* Thanks IE 10. */
      .hidden {
        display: none !important;
      }
    </style>

    <div id="tooltip" class="hidden">
      <content></content>
    </div>
  </template>

  <script>
    Polymer({
      is: 'paper-tooltip',

      hostAttributes: {
        role: 'tooltip',
        tabindex: -1
      },

      behaviors: [
        Polymer.NeonAnimationRunnerBehavior
      ],

      properties: {
        /**
         * The id of the element that the tooltip is anchored to. This element
         * must be a sibling of the tooltip.
         */
        for: {
          type: String,
          observer: '_forChanged'
        },

        /**
         * Positions the tooltip to the top, right, bottom, left of its content.
         */
        position: {
          type: String,
          value: 'bottom'
        },

        /**
         * If true, no parts of the tooltip will ever be shown offscreen.
         */
        fitToVisibleBounds: {
          type: Boolean,
          value: false
        },

        /**
         * The spacing between the top of the tooltip and the element it is
         * anchored to.
         */
        offset: {
          type: Number,
          value: 14
        },

        /**
         * This property is deprecated, but left over so that it doesn't
         * break exiting code. Please use `offset` instead. If both `offset` and
         * `marginTop` are provided, `marginTop` will be ignored.
         * @deprecated since version 1.0.3
         */
        marginTop: {
          type: Number,
          value: 14
        },

        animationConfig: {
          type: Object,
          value: function() {
            return {
              'entry': [{
                name: 'fade-in-animation',
                node: this,
                timing: {delay: 500}
              }],
              'exit': [{
                name: 'fade-out-animation',
                node: this
              }]
            }
          }
        },

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

      listeners: {
        'neon-animation-finish': '_onAnimationFinish'
      },

      /**
       * Returns the target element that this tooltip is anchored to. It is
       * either the element given by the `for` attribute, or the immediate parent
       * of the tooltip.
       */
      get target () {
        var parentNode = Polymer.dom(this).parentNode;
        // If the parentNode is a document fragment, then we need to use the host.
        var ownerRoot = Polymer.dom(this).getOwnerRoot();

        var target;
        if (this.for) {
          target = Polymer.dom(ownerRoot).querySelector('#' + this.for);
        } else {
          target = parentNode.nodeType == Node.DOCUMENT_FRAGMENT_NODE ?
              ownerRoot.host : parentNode;
        }

        return target;
      },

      attached: function() {
        this._target = this.target;

        this.listen(this._target, 'mouseenter', 'show');
        this.listen(this._target, 'focus', 'show');
        this.listen(this._target, 'mouseleave', 'hide');
        this.listen(this._target, 'blur', 'hide');
      },

      detached: function() {
        if (this._target) {
          this.unlisten(this._target, 'mouseenter', 'show');
          this.unlisten(this._target, 'focus', 'show');
          this.unlisten(this._target, 'mouseleave', 'hide');
          this.unlisten(this._target, 'blur', 'hide');
        }
      },

      show: function() {
        if (this._showing)
          return;

        if (Polymer.dom(this).textContent.trim() === '')
          return;

        this.cancelAnimation();

        this.toggleClass('hidden', false, this.$.tooltip);
        this.updatePosition();
        this._showing = true;

        this.playAnimation('entry');
      },

      hide: function() {
        if (!this._showing)
          return;

        this._showing = false;
        this.playAnimation('exit');
      },

      _forChanged: function() {
        this._target = this.target;
      },

      updatePosition: function() {
        if (!this._target)
          return;

        var offset = this.offset;
        // If a marginTop has been provided by the user (pre 1.0.3), use it.
        if (this.marginTop != 14 && this.offset == 14)
          offset = this.marginTop;

        var parentRect = this.offsetParent.getBoundingClientRect();
        var targetRect = this._target.getBoundingClientRect();
        var thisRect = this.getBoundingClientRect();

        var horizontalCenterOffset = (targetRect.width - thisRect.width) / 2;
        var verticalCenterOffset = (targetRect.height - thisRect.height) / 2;

        var targetLeft = targetRect.left - parentRect.left;
        var targetTop = targetRect.top - parentRect.top;

        var tooltipLeft, tooltipTop;

        switch (this.position) {
          case 'top':
            tooltipLeft = targetLeft + horizontalCenterOffset;
            tooltipTop = targetTop - thisRect.height - offset;
            break;
          case 'bottom':
            tooltipLeft = targetLeft + horizontalCenterOffset;
            tooltipTop = targetTop + targetRect.height + offset;
            break;
          case 'left':
            tooltipLeft = targetLeft - thisRect.width - offset;
            tooltipTop = targetTop + verticalCenterOffset;
            break;
          case 'right':
            tooltipLeft = targetLeft + targetRect.width + offset;
            tooltipTop = targetTop + verticalCenterOffset;
            break;
        }

        // TODO(noms): This should use IronFitBehavior if possible.
        if (this.fitToVisibleBounds) {
          // Clip the left/right side.
          if (tooltipLeft + thisRect.width > window.innerWidth) {
            this.style.right = '0px';
            this.style.left = 'auto';
          } else {
            this.style.left = Math.max(0, tooltipLeft) + 'px';
            this.style.right = 'auto';
          }

          // Clip the top/bottom side.
          if (tooltipTop + thisRect.height > window.innerHeight) {
            this.style.bottom = '0px';
            this.style.top = 'auto';
          } else {
            this.style.top = Math.max(0, tooltipTop) + 'px';
            this.style.bottom = 'auto';
          }
        } else {
          this.style.left = tooltipLeft + 'px';
          this.style.top = tooltipTop + 'px';
        }

      },

      _onAnimationFinish: function() {
        if (!this._showing) {
          this.toggleClass('hidden', true, this.$.tooltip);
        }
      },
    });
  </script>
</dom-module>