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@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
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-->

<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../iron-meta/iron-meta.html">

<script>

  /**
   * Use `Polymer.IronValidatableBehavior` to implement an element that validates user input.
   *
   * ### Accessiblity
   *
   * Changing the `invalid` property, either manually or by calling `validate()` will update the
   * `aria-invalid` attribute.
   *
   * @demo demo/index.html
   * @polymerBehavior
   */
  Polymer.IronValidatableBehavior = {

    properties: {

      /**
       * Namespace for this validator.
       */
      validatorType: {
        type: String,
        value: 'validator'
      },

      /**
       * Name of the validator to use.
       */
      validator: {
        type: String
      },

      /**
       * True if the last call to `validate` is invalid.
       */
      invalid: {
        notify: true,
        reflectToAttribute: true,
        type: Boolean,
        value: false
      },

      _validatorMeta: {
        type: Object
      }

    },

    observers: [
      '_invalidChanged(invalid)'
    ],

    get _validator() {
      return this._validatorMeta && this._validatorMeta.byKey(this.validator);
    },

    ready: function() {
      this._validatorMeta = new Polymer.IronMeta({type: this.validatorType});
    },

    _invalidChanged: function() {
      if (this.invalid) {
        this.setAttribute('aria-invalid', 'true');
      } else {
        this.removeAttribute('aria-invalid');
      }
    },

    /**
     * @return {boolean} True if the validator `validator` exists.
     */
    hasValidator: function() {
      return this._validator != null;
    },

    /**
     * @param {Object} values Passed to the validator's `validate()` function.
     * @return {boolean} True if `values` is valid.
     */
    validate: function(values) {
      var valid = true;
      if (this.hasValidator()) {
        valid = this._validator.validate(values);
      }

      this.invalid = !valid;
      return valid;
    }

  };

</script>