SGH / COMPONENTS

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<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../iron-behaviors/iron-control-state.html">

<script>

  /**
   * Use `Polymer.PaperInputBehavior` to implement inputs with `<paper-input-container>`. This
   * behavior is implemented by `<paper-input>`. It exposes a number of properties from
   * `<paper-input-container>` and `<input is="iron-input">` and they should be bound in your
   * template.
   *
   * The input element can be accessed by the `inputElement` property if you need to access
   * properties or methods that are not exposed.
   * @polymerBehavior Polymer.PaperInputBehavior
   */
  Polymer.PaperInputBehaviorImpl = {

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

      /**
       * The label for this input. Bind this to `<paper-input-container>`'s `label` property.
       */
      label: {
        type: String
      },

      /**
       * The value for this input. Bind this to the `<input is="iron-input">`'s `bindValue`
       * property, or the value property of your input that is `notify:true`.
       */
      value: {
        notify: true,
        type: String
      },

      /**
       * Set to true to disable this input. Bind this to both the `<paper-input-container>`'s
       * and the input's `disabled` property.
       */
      disabled: {
        type: Boolean,
        value: false
      },

      /**
       * Returns true if the value is invalid. Bind this to both the `<paper-input-container>`'s
       * and the input's `invalid` property.
       */
      invalid: {
        type: Boolean,
        value: false,
        notify: true
      },

      /**
       * Set to true to prevent the user from entering invalid input. Bind this to the
       * `<input is="iron-input">`'s `preventInvalidInput` property.
       */
      preventInvalidInput: {
        type: Boolean
      },

      /**
       * Set this to specify the pattern allowed by `preventInvalidInput`. Bind this to the
       * `<input is="iron-input">`'s `allowedPattern` property.
       */
      allowedPattern: {
        type: String
      },

      /**
       * The type of the input. The supported types are `text`, `number` and `password`. Bind this
       * to the `<input is="iron-input">`'s `type` property.
       */
      type: {
        type: String
      },

      /**
       * The datalist of the input (if any). This should match the id of an existing `<datalist>`. Bind this
       * to the `<input is="iron-input">`'s `list` property.
       */
      list: {
        type: String
      },

      /**
       * A pattern to validate the `input` with. Bind this to the `<input is="iron-input">`'s
       * `pattern` property.
       */
      pattern: {
        type: String
      },

      /**
       * Set to true to mark the input as required. Bind this to the `<input is="iron-input">`'s
       * `required` property.
       */
      required: {
        type: Boolean,
        value: false
      },

      /**
       * The error message to display when the input is invalid. Bind this to the
       * `<paper-input-error>`'s content, if using.
       */
      errorMessage: {
        type: String
      },

      /**
       * Set to true to show a character counter.
       */
      charCounter: {
        type: Boolean,
        value: false
      },

      /**
       * Set to true to disable the floating label. Bind this to the `<paper-input-container>`'s
       * `noLabelFloat` property.
       */
      noLabelFloat: {
        type: Boolean,
        value: false
      },

      /**
       * Set to true to always float the label. Bind this to the `<paper-input-container>`'s
       * `alwaysFloatLabel` property.
       */
      alwaysFloatLabel: {
        type: Boolean,
        value: false
      },

      /**
       * Set to true to auto-validate the input value. Bind this to the `<paper-input-container>`'s
       * `autoValidate` property.
       */
      autoValidate: {
        type: Boolean,
        value: false
      },

      /**
       * Name of the validator to use. Bind this to the `<input is="iron-input">`'s `validator`
       * property.
       */
      validator: {
        type: String
      },

      // HTMLInputElement attributes for binding if needed

      /**
       * Bind this to the `<input is="iron-input">`'s `autocomplete` property.
       */
      autocomplete: {
        type: String,
        value: 'off'
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `autofocus` property.
       */
      autofocus: {
        type: Boolean
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `inputmode` property.
       */
      inputmode: {
        type: String
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `minlength` property.
       */
      minlength: {
        type: Number
      },

      /**
       * The maximum length of the input value. Bind this to the `<input is="iron-input">`'s
       * `maxlength` property.
       */
      maxlength: {
        type: Number
      },

      /**
       * The minimum (numeric or date-time) input value.
       * Bind this to the `<input is="iron-input">`'s `min` property.
       */
      min: {
        type: String
      },

      /**
       * The maximum (numeric or date-time) input value.
       * Can be a String (e.g. `"2000-1-1"`) or a Number (e.g. `2`).
       * Bind this to the `<input is="iron-input">`'s `max` property.
       */
      max: {
        type: String
      },

      /**
       * Limits the numeric or date-time increments.
       * Bind this to the `<input is="iron-input">`'s `step` property.
       */
      step: {
        type: String
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `name` property.
       */
      name: {
        type: String
      },

      /**
       * A placeholder string in addition to the label. If this is set, the label will always float.
       */
      placeholder: {
        type: String,
        // need to set a default so _computeAlwaysFloatLabel is run
        value: ''
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `readonly` property.
       */
      readonly: {
        type: Boolean,
        value: false
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `size` property.
       */
      size: {
        type: Number
      },

      // Nonstandard attributes for binding if needed

      /**
       * Bind this to the `<input is="iron-input">`'s `autocapitalize` property.
       */
      autocapitalize: {
        type: String,
        value: 'none'
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `autocorrect` property.
       */
      autocorrect: {
        type: String,
        value: 'off'
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `autosave` property, used with type=search.
       */
      autosave: {
        type: String
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `results` property, , used with type=search.
       */
      results: {
        type: Number
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `accept` property, , used with type=file.
       */
      accept: {
        type: String
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `multiple` property, , used with type=file.
       */
      multiple: {
        type: Boolean
      },

      _ariaDescribedBy: {
        type: String,
        value: ''
      }

    },

    listeners: {
      'addon-attached': '_onAddonAttached'
    },

    observers: [
      '_focusedControlStateChanged(focused)'
    ],

    /**
     * Returns a reference to the input element.
     */
    get inputElement() {
      return this.$.input;
    },

    attached: function() {
      this._updateAriaLabelledBy();
    },

    _appendStringWithSpace: function(str, more) {
      if (str) {
        str = str + ' ' + more;
      } else {
        str = more;
      }
      return str;
    },

    _onAddonAttached: function(event) {
      var target = event.path ? event.path[0] : event.target;
      if (target.id) {
        this._ariaDescribedBy = this._appendStringWithSpace(this._ariaDescribedBy, target.id);
      } else {
        var id = 'paper-input-add-on-' + Math.floor((Math.random() * 100000));
        target.id = id;
        this._ariaDescribedBy = this._appendStringWithSpace(this._ariaDescribedBy, id);
      }
    },

    /**
     * Validates the input element and sets an error style if needed.
     *
     * @return {boolean}
     */
    validate: function() {
      return this.inputElement.validate();
    },

    /**
     * If `autoValidate` is true, then validates the element.
     */
    _handleAutoValidate: function() {
      if (this.autoValidate)
        this.validate();
    },

    /**
     * Restores the cursor to its original position after updating the value.
     * @param {string} newValue The value that should be saved.
     */
    updateValueAndPreserveCaret: function(newValue) {
      // Not all elements might have selection, and even if they have the
      // right properties, accessing them might throw an exception (like for
      // <input type=number>)
      try {
        var start = this.inputElement.selectionStart;
        this.value = newValue;

        // The cursor automatically jumps to the end after re-setting the value,
        // so restore it to its original position.
        this.inputElement.selectionStart = start;
        this.inputElement.selectionEnd = start;
      } catch (e) {
        // Just set the value and give up on the caret.
        this.value = newValue;
      }
    },

    _computeAlwaysFloatLabel: function(alwaysFloatLabel, placeholder) {
      return placeholder || alwaysFloatLabel;
    },

    _focusedControlStateChanged: function(focused) {
      // IronControlState stops the focus and blur events in order to redispatch them on the host
      // element, but paper-input-container listens to those events. Since there are more
      // pending work on focus/blur in IronControlState, I'm putting in this hack to get the
      // input focus state working for now.
      if (!this.$.container) {
        this.$.container = Polymer.dom(this.root).querySelector('paper-input-container');
        if (!this.$.container) {
          return;
        }
      }
      if (focused) {
        this.$.container._onFocus();
      } else {
        this.$.container._onBlur();
      }
    },

    _updateAriaLabelledBy: function() {
      var label = Polymer.dom(this.root).querySelector('label');
      if (!label) {
        this._ariaLabelledBy = '';
        return;
      }
      var labelledBy;
      if (label.id) {
        labelledBy = label.id;
      } else {
        labelledBy = 'paper-input-label-' + new Date().getUTCMilliseconds();
        label.id = labelledBy;
      }
      this._ariaLabelledBy = labelledBy;
    },

    _onChange:function(event) {
      // In the Shadow DOM, the `change` event is not leaked into the
      // ancestor tree, so we must do this manually.
      // See https://w3c.github.io/webcomponents/spec/shadow/#events-that-are-not-leaked-into-ancestor-trees.
      if (this.shadowRoot) {
        this.fire(event.type, {sourceEvent: event}, {
          node: this,
          bubbles: event.bubbles,
          cancelable: event.cancelable
        });
      }
    }

  };

  /** @polymerBehavior */
  Polymer.PaperInputBehavior = [Polymer.IronControlState, Polymer.PaperInputBehaviorImpl];

</script>