/**
 * @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 Data Table Card 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 MaterialDataTable = function MaterialDataTable(element) {
    this.element_ = element;

    // Initialize instance.
    this.init();
  };

  window['MaterialDataTable'] = MaterialDataTable;

  /**
   * Store constants in one place so they can be updated easily.
   *
   * @enum {string | number}
   * @private
   */
  MaterialDataTable.prototype.Constant_ = {
    // None at the moment.
  };

  /**
   * 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
   */
  MaterialDataTable.prototype.CssClasses_ = {
    DATA_TABLE: 'mdl-data-table',
    SELECTABLE: 'mdl-data-table--selectable',
    SELECT_ELEMENT: 'mdl-data-table__select',
    IS_SELECTED: 'is-selected',
    IS_UPGRADED: 'is-upgraded'
  };

  /**
   * Generates and returns a function that toggles the selection state of a
   * single row (or multiple rows).
   *
   * @param {Element} checkbox Checkbox that toggles the selection state.
   * @param {HTMLElement} row Row to toggle when checkbox changes.
   * @param {(Array<Object>|NodeList)=} opt_rows Rows to toggle when checkbox changes.
   * @private
   */
  MaterialDataTable.prototype.selectRow_ = function(checkbox, row, opt_rows) {
    if (row) {
      return function() {
        if (checkbox.checked) {
          row.classList.add(this.CssClasses_.IS_SELECTED);
        } else {
          row.classList.remove(this.CssClasses_.IS_SELECTED);
        }
      }.bind(this);
    }

    if (opt_rows) {
      return function() {
        var i;
        var el;
        if (checkbox.checked) {
          for (i = 0; i < opt_rows.length; i++) {
            el = opt_rows[i].querySelector('td').querySelector('.mdl-checkbox');
            el['MaterialCheckbox'].check();
            opt_rows[i].classList.add(this.CssClasses_.IS_SELECTED);
          }
        } else {
          for (i = 0; i < opt_rows.length; i++) {
            el = opt_rows[i].querySelector('td').querySelector('.mdl-checkbox');
            el['MaterialCheckbox'].uncheck();
            opt_rows[i].classList.remove(this.CssClasses_.IS_SELECTED);
          }
        }
      }.bind(this);
    }
  };

  /**
   * Creates a checkbox for a single or or multiple rows and hooks up the
   * event handling.
   *
   * @param {HTMLElement} row Row to toggle when checkbox changes.
   * @param {(Array<Object>|NodeList)=} opt_rows Rows to toggle when checkbox changes.
   * @private
   */
  MaterialDataTable.prototype.createCheckbox_ = function(row, opt_rows) {
    var label = document.createElement('label');
    var labelClasses = [
      'mdl-checkbox',
      'mdl-js-checkbox',
      'mdl-js-ripple-effect',
      this.CssClasses_.SELECT_ELEMENT
    ];
    label.className = labelClasses.join(' ');
    var checkbox = document.createElement('input');
    checkbox.type = 'checkbox';
    checkbox.classList.add('mdl-checkbox__input');
    checkbox.addEventListener('change',
        this.selectRow_(checkbox, row, opt_rows));

    label.appendChild(checkbox);
    componentHandler.upgradeElement(label, 'MaterialCheckbox');
    return label;
  };

  /**
   * Initialize element.
   */
  MaterialDataTable.prototype.init = function() {
    if (this.element_) {
      var firstHeader = this.element_.querySelector('th');
      var rows = this.element_.querySelector('tbody').querySelectorAll('tr');

      if (this.element_.classList.contains(this.CssClasses_.SELECTABLE)) {
        var th = document.createElement('th');
        var headerCheckbox = this.createCheckbox_(null, rows);
        th.appendChild(headerCheckbox);
        firstHeader.parentElement.insertBefore(th, firstHeader);

        for (var i = 0; i < rows.length; i++) {
          var firstCell = rows[i].querySelector('td');
          if (firstCell) {
            var td = document.createElement('td');
            var rowCheckbox = this.createCheckbox_(rows[i]);
            td.appendChild(rowCheckbox);
            rows[i].insertBefore(td, firstCell);
          }
        }
      }

      this.element_.classList.add(this.CssClasses_.IS_UPGRADED);
    }
  };

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