<!--
@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="../paper-ripple/paper-ripple.html">
<link rel="import" href="../paper-styles/default-theme.html">
<link rel="import" href="../paper-behaviors/paper-inky-focus-behavior.html">

<!--

`paper-checkbox` is a button that can be either checked or unchecked.  User
can tap the checkbox to check or uncheck it.  Usually you use checkboxes
to allow user to select multiple options from a set.  If you have a single
ON/OFF option, avoid using a single checkbox and use `paper-toggle-button`
instead.

Example:

    <paper-checkbox>label</paper-checkbox>

    <paper-checkbox checked> label</paper-checkbox>

### Styling

The following custom properties and mixins are available for styling:

Custom property | Description | Default
----------------|-------------|----------
`--paper-checkbox-unchecked-background-color` | Checkbox background color when the input is not checked | `transparent`
`--paper-checkbox-unchecked-color` | Checkbox border color when the input is not checked | `--primary-text-color`
`--paper-checkbox-unchecked-ink-color` | Selected/focus ripple color when the input is not checked | `--primary-text-color`
`--paper-checkbox-checked-color` | Checkbox color when the input is checked | `--default-primary-color`
`--paper-checkbox-checked-ink-color` | Selected/focus ripple color when the input is checked | `--default-primary-color`
`--paper-checkbox-checkmark-color` | Checkmark color | `white`
`--paper-checkbox-label-color` | Label color | `--primary-text-color`

@demo demo/index.html
-->

<dom-module id="paper-checkbox">
  <link rel="import" type="css" href="paper-checkbox.css">

  <template>

    <div id="checkboxContainer">
      <paper-ripple id="ink" class="circle" center checked$="[[checked]]"></paper-ripple>
      <div id="checkbox" class$="[[_computeCheckboxClass(checked)]]">
        <div id="checkmark" class$="[[_computeCheckmarkClass(checked)]]"></div>
      </div>
    </div>

    <div id="checkboxLabel" aria-hidden="true"><content></content></div>

  </template>

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

      behaviors: [
        Polymer.PaperInkyFocusBehavior
      ],

      hostAttributes: {
        role: 'checkbox',
        'aria-checked': false,
        tabindex: 0
      },

      properties: {
        /**
         * Fired when the checked state changes due to user interaction.
         *
         * @event change
         */

        /**
         * Fired when the checked state changes.
         *
         * @event iron-change
         */

        /**
         * Gets or sets the state, `true` is checked and `false` is unchecked.
         */
        checked: {
          type: Boolean,
          value: false,
          reflectToAttribute: true,
          notify: true,
          observer: '_checkedChanged'
        },

        /**
         * If true, the button toggles the active state with each tap or press
         * of the spacebar.
         */
        toggles: {
          type: Boolean,
          value: true,
          reflectToAttribute: true
        }
      },

      ready: function() {
        if (Polymer.dom(this).textContent == '') {
          this.$.checkboxLabel.hidden = true;
        } else {
          this.setAttribute('aria-label', Polymer.dom(this).textContent);
        }
        this._isReady = true;
      },

      // button-behavior hook
      _buttonStateChanged: function() {
        if (this.disabled) {
          return;
        }
        if (this._isReady) {
          this.checked = this.active;
        }
      },

      _checkedChanged: function(checked) {
        this.setAttribute('aria-checked', this.checked ? 'true' : 'false');
        this.active = this.checked;
        this.fire('iron-change');
      },

      _computeCheckboxClass: function(checked) {
        if (checked) {
          return 'checked';
        }
        return '';
      },

      _computeCheckmarkClass: function(checked) {
        if (!checked) {
          return 'hidden';
        }
        return '';
      }
    })
  </script>

</dom-module>