text: /**
   * @license
   * Copyright 2016 Google LLC
   *
   * 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.
   */
  
  /**
   * @fileoverview Javascript for Block Library's Storage Class.
   * Depends on Block Library for its namespace.
   *
   * @author quachtina96 (Tina Quach)
   */
  
  'use strict';
  
  /**
   * Represents a block library's storage.
   * @param {string} blockLibraryName Desired name of Block Library, also used
   *    to create the key for where it's stored in local storage.
   * @param {!Object=} opt_blocks Object mapping block type to XML.
   * @constructor
   */
  function BlockLibraryStorage(blockLibraryName, opt_blocks) {
    // Add prefix to this.name to avoid collisions in local storage.
    this.name = 'BlockLibraryStorage.' + blockLibraryName;
    if (!opt_blocks) {
      // Initialize this.blocks by loading from local storage.
      this.loadFromLocalStorage();
      if (this.blocks == null) {
        this.blocks = Object.create(null);
        // The line above is equivalent of {} except that this object is TRULY
        // empty. It doesn't have built-in attributes/functions such as length or
        // toString.
        this.saveToLocalStorage();
      }
    } else {
      this.blocks = opt_blocks;
      this.saveToLocalStorage();
    }
  };
  
  /**
   * Reads the named block library from local storage and saves it in this.blocks.
   */
  BlockLibraryStorage.prototype.loadFromLocalStorage = function() {
    var object = localStorage[this.name];
    this.blocks = object ? JSON.parse(object) : null;
  };
  
  /**
   * Writes the current block library (this.blocks) to local storage.
   */
  BlockLibraryStorage.prototype.saveToLocalStorage = function() {
    localStorage[this.name] = JSON.stringify(this.blocks);
  };
  
  /**
   * Clears the current block library.
   */
  BlockLibraryStorage.prototype.clear = function() {
    this.blocks = Object.create(null);
    // The line above is equivalent of {} except that this object is TRULY
    // empty. It doesn't have built-in attributes/functions such as length or
    // toString.
  };
  
  /**
   * Saves block to block library.
   * @param {string} blockType Type of block.
   * @param {Element} blockXML The block's XML pulled from workspace.
   */
  BlockLibraryStorage.prototype.addBlock = function(blockType, blockXML) {
    var prettyXml = Blockly.Xml.domToPrettyText(blockXML);
    this.blocks[blockType] = prettyXml;
  };
  
  /**
   * Removes block from current block library (this.blocks).
   * @param {string} blockType Type of block.
   */
  BlockLibraryStorage.prototype.removeBlock = function(blockType) {
    delete this.blocks[blockType];
  };
  
  /**
   * Returns the XML of given block type stored in current block library
   * (this.blocks).
   * @param {string} blockType Type of block.
   * @return {Element} The XML that represents the block type or null.
   */
  BlockLibraryStorage.prototype.getBlockXml = function(blockType) {
    var xml = this.blocks[blockType] || null;
    if (xml) {
      var xml = Blockly.Xml.textToDom(xml);
    }
    return xml;
  };
  
  
  /**
   * Returns map of each block type to its corresponding XML stored in current
   * block library (this.blocks).
   * @param {!Array.<string>} blockTypes Types of blocks.
   * @return {!Object} Map of block type to corresponding XML.
   */
  BlockLibraryStorage.prototype.getBlockXmlMap = function(blockTypes) {
    var blockXmlMap = Object.create(null);
    for (var i = 0; i < blockTypes.length; i++) {
      var blockType = blockTypes[i];
      var xml = this.getBlockXml(blockType);
      blockXmlMap[blockType] = xml;
    }
    return blockXmlMap;
  };
  
  /**
   * Returns array of all block types stored in current block library.
   * @return {!Array.<string>} Array of block types stored in library.
   */
  BlockLibraryStorage.prototype.getBlockTypes = function() {
    return Object.keys(this.blocks);
  };
  
  /**
   * Checks to see if block library is empty.
   * @return {boolean} True if empty, false otherwise.
   */
  BlockLibraryStorage.prototype.isEmpty = function() {
    for (var blockType in this.blocks) {
      return false;
    }
    return true;
  };
  
  /**
   * Returns array of all block types stored in current block library.
   * @return {!Array.<string>} Map of block type to corresponding XML text.
   */
  BlockLibraryStorage.prototype.getBlockXmlTextMap = function() {
    return this.blocks;
  };
  
  /**
   * Returns boolean of whether or not a given blockType is stored in block
   * library.
   * @param {string} blockType Type of block.
   * @return {boolean} Whether or not blockType is stored in block library.
   */
  BlockLibraryStorage.prototype.has = function(blockType) {
    return !!this.blocks[blockType];
  };
  