/**
 * @license
 * Copyright 2015 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

(function() {
  'use strict';

  /**
   * Class constructor for Textfield MDL component.
   * Implements MDL component design pattern defined at:
   * https://github.com/jasonmayes/mdl-component-design-pattern
   *
   * @constructor
   * @param {HTMLElement} element The element that will be upgraded.
   */
  var MaterialTextfield = function MaterialTextfield(element) {
    this.element_ = element;
    this.maxRows = this.Constant_.NO_MAX_ROWS;
    // Initialize instance.
    this.init();
  };
  window['MaterialTextfield'] = MaterialTextfield;

  /**
   * Store constants in one place so they can be updated easily.
   *
   * @enum {string | number}
   * @private
   */
  MaterialTextfield.prototype.Constant_ = {
    NO_MAX_ROWS: -1,
    MAX_ROWS_ATTRIBUTE: 'maxrows'
  };

  /**
   * Store strings for class names defined by this component that are used in
   * JavaScript. This allows us to simply change it in one place should we
   * decide to modify at a later date.
   *
   * @enum {string}
   * @private
   */
  MaterialTextfield.prototype.CssClasses_ = {
    LABEL: 'mdl-textfield__label',
    INPUT: 'mdl-textfield__input',
    IS_DIRTY: 'is-dirty',
    IS_FOCUSED: 'is-focused',
    IS_DISABLED: 'is-disabled',
    IS_INVALID: 'is-invalid',
    IS_UPGRADED: 'is-upgraded'
  };

  /**
   * Handle input being entered.
   *
   * @param {Event} event The event that fired.
   * @private
   */
  MaterialTextfield.prototype.onKeyDown_ = function(event) {
    var currentRowCount = event.target.value.split('\n').length;
    if (event.keyCode === 13) {
      if (currentRowCount >= this.maxRows) {
        event.preventDefault();
      }
    }
  };

  /**
   * Handle focus.
   *
   * @param {Event} event The event that fired.
   * @private
   */
  MaterialTextfield.prototype.onFocus_ = function(event) {
    this.element_.classList.add(this.CssClasses_.IS_FOCUSED);
  };

  /**
   * Handle lost focus.
   *
   * @param {Event} event The event that fired.
   * @private
   */
  MaterialTextfield.prototype.onBlur_ = function(event) {
    this.element_.classList.remove(this.CssClasses_.IS_FOCUSED);
  };

  /**
   * Handle class updates.
   *
   * @private
   */
  MaterialTextfield.prototype.updateClasses_ = function() {
    this.checkDisabled();
    this.checkValidity();
    this.checkDirty();
  };

  // Public methods.

  /**
   * Check the disabled state and update field accordingly.
   *
   * @public
   */
  MaterialTextfield.prototype.checkDisabled = function() {
    if (this.input_.disabled) {
      this.element_.classList.add(this.CssClasses_.IS_DISABLED);
    } else {
      this.element_.classList.remove(this.CssClasses_.IS_DISABLED);
    }
  };
  MaterialTextfield.prototype['checkDisabled'] =
      MaterialTextfield.prototype.checkDisabled;

  /**
   * Check the validity state and update field accordingly.
   *
   * @public
   */
  MaterialTextfield.prototype.checkValidity = function() {
    if (this.input_.validity) {
      if (this.input_.validity.valid) {
        this.element_.classList.remove(this.CssClasses_.IS_INVALID);
      } else {
        this.element_.classList.add(this.CssClasses_.IS_INVALID);
      }
    }
  };
  MaterialTextfield.prototype['checkValidity'] =
      MaterialTextfield.prototype.checkValidity;

  /**
   * Check the dirty state and update field accordingly.
   *
   * @public
   */
  MaterialTextfield.prototype.checkDirty = function() {
    if (this.input_.value && this.input_.value.length > 0) {
      this.element_.classList.add(this.CssClasses_.IS_DIRTY);
    } else {
      this.element_.classList.remove(this.CssClasses_.IS_DIRTY);
    }
  };
  MaterialTextfield.prototype['checkDirty'] =
      MaterialTextfield.prototype.checkDirty;

  /**
   * Disable text field.
   *
   * @public
   */
  MaterialTextfield.prototype.disable = function() {
    this.input_.disabled = true;
    this.updateClasses_();
  };
  MaterialTextfield.prototype['disable'] = MaterialTextfield.prototype.disable;

  /**
   * Enable text field.
   *
   * @public
   */
  MaterialTextfield.prototype.enable = function() {
    this.input_.disabled = false;
    this.updateClasses_();
  };
  MaterialTextfield.prototype['enable'] = MaterialTextfield.prototype.enable;

  /**
   * Update text field value.
   *
   * @param {string} value The value to which to set the control (optional).
   * @public
   */
  MaterialTextfield.prototype.change = function(value) {

    this.input_.value = value || '';
    this.updateClasses_();
  };
  MaterialTextfield.prototype['change'] = MaterialTextfield.prototype.change;

  /**
   * Initialize element.
   */
  MaterialTextfield.prototype.init = function() {

    if (this.element_) {
      this.label_ = this.element_.querySelector('.' + this.CssClasses_.LABEL);
      this.input_ = this.element_.querySelector('.' + this.CssClasses_.INPUT);

      if (this.input_) {
        if (this.input_.hasAttribute(
              /** @type {string} */ (this.Constant_.MAX_ROWS_ATTRIBUTE))) {
          this.maxRows = parseInt(this.input_.getAttribute(
              /** @type {string} */ (this.Constant_.MAX_ROWS_ATTRIBUTE)), 10);
          if (isNaN(this.maxRows)) {
            this.maxRows = this.Constant_.NO_MAX_ROWS;
          }
        }

        this.boundUpdateClassesHandler = this.updateClasses_.bind(this);
        this.boundFocusHandler = this.onFocus_.bind(this);
        this.boundBlurHandler = this.onBlur_.bind(this);
        this.input_.addEventListener('input', this.boundUpdateClassesHandler);
        this.input_.addEventListener('focus', this.boundFocusHandler);
        this.input_.addEventListener('blur', this.boundBlurHandler);

        if (this.maxRows !== this.Constant_.NO_MAX_ROWS) {
          // TODO: This should handle pasting multi line text.
          // Currently doesn't.
          this.boundKeyDownHandler = this.onKeyDown_.bind(this);
          this.input_.addEventListener('keydown', this.boundKeyDownHandler);
        }
        var invalid = this.element_.classList
          .contains(this.CssClasses_.IS_INVALID);
        this.updateClasses_();
        this.element_.classList.add(this.CssClasses_.IS_UPGRADED);
        if (invalid) {
          this.element_.classList.add(this.CssClasses_.IS_INVALID);
        }
      }
    }
  };

  /**
   * Downgrade the component
   *
   * @private
   */
  MaterialTextfield.prototype.mdlDowngrade_ = function() {
    this.input_.removeEventListener('input', this.boundUpdateClassesHandler);
    this.input_.removeEventListener('focus', this.boundFocusHandler);
    this.input_.removeEventListener('blur', this.boundBlurHandler);
    if (this.boundKeyDownHandler) {
      this.input_.removeEventListener('keydown', this.boundKeyDownHandler);
    }
  };

  /**
   * Public alias for the downgrade method.
   *
   * @public
   */
  MaterialTextfield.prototype.mdlDowngrade =
      MaterialTextfield.prototype.mdlDowngrade_;

  MaterialTextfield.prototype['mdlDowngrade'] =
      MaterialTextfield.prototype.mdlDowngrade;

  // The component registers itself. It can assume componentHandler is available
  // in the global scope.
  componentHandler.register({
    constructor: MaterialTextfield,
    classAsString: 'MaterialTextfield',
    cssClass: 'mdl-js-textfield',
    widget: true
  });
})();