/**
 * @license
 * Visual Blocks Editor
 *
 * Copyright 2012 Google Inc.
 * https://developers.google.com/blockly/
 *
 * 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 List blocks for Blockly.
 * @author fraser@google.com (Neil Fraser)
 */
'use strict';

goog.provide('Blockly.Blocks.lists');

goog.require('Blockly.Blocks');


Blockly.Blocks['lists_create_empty'] = {
  /**
   * Block for creating an empty list.
   * The 'list_create_with' block is preferred as it is more flexible.
   * <block type="lists_create_with">
   *   <mutation items="0"></mutation>
   * </block>
   * @this Blockly.Block
   */
  init: function() {
    this.jsonInit({
      "message0": Blockly.Msg.LISTS_CREATE_EMPTY_TITLE,
      "output": "Array",
      "colour": Blockly.Variables.COLOUR.OPERATORS,
      "tooltip": Blockly.Msg.LISTS_CREATE_EMPTY_TOOLTIP,
      "helpUrl": Blockly.Msg.LISTS_CREATE_EMPTY_HELPURL
    });
  }
};

Blockly.Blocks['lists_create_with'] = {
  /**
   * Block for creating a list with any number of elements of any type.
   * @this Blockly.Block
   */
  init: function() {
    this.setHelpUrl(Blockly.Msg.LISTS_CREATE_WITH_HELPURL);
    this.setColour(Blockly.Variables.COLOUR.OPERATORS);
    this.itemCount_ = 3;
    this.updateShape_();
    this.setOutput(true, 'Array');
    this.setMutator(new Blockly.Mutator(['lists_create_with_item']));
    this.setTooltip(Blockly.Msg.LISTS_CREATE_WITH_TOOLTIP);
  },
  /**
   * Create an object to represent list inputs.
   * @return {object} mutation data.
   * @this Blockly.Block
   */
  mutationToObject: function() {
    return {
      'items': this.itemCount_
    };
  },
  /**
   * Parse mutation data to restore the list inputs.
   * @param {object} obj Mutation data object.
   * @this Blockly.Block
   */
  objectToMutation: function(obj) {
    this.itemCount_ = obj['items'];
    this.updateShape_();
  },
  /**
   * Create XML to represent list inputs.
   * @return {!Element} XML storage element.
   * @this Blockly.Block
   */
  mutationToDom: function() {
    var container = document.createElement('mutation');
    container.setAttribute('items', this.itemCount_);
    return container;
  },
  /**
   * Parse XML to restore the list inputs.
   * @param {!Element} xmlElement XML storage element.
   * @this Blockly.Block
   */
  domToMutation: function(xmlElement) {
    this.itemCount_ = parseInt(xmlElement.getAttribute('items'), 10);
    this.updateShape_();
  },
  /**
   * Populate the mutator's dialog with this block's components.
   * @param {!Blockly.Workspace} workspace Mutator's workspace.
   * @return {!Blockly.Block} Root block in mutator.
   * @this Blockly.Block
   */
  decompose: function(workspace) {
    var containerBlock =
        Blockly.Block.obtain(workspace, 'lists_create_with_container');
    containerBlock.initSvg();
    var connection = containerBlock.getInput('STACK').connection;
    for (var i = 0; i < this.itemCount_; i++) {
      var itemBlock = Blockly.Block.obtain(workspace, 'lists_create_with_item');
      itemBlock.initSvg();
      connection.connect(itemBlock.previousConnection);
      connection = itemBlock.nextConnection;
    }
    return containerBlock;
  },
  /**
   * Reconfigure this block based on the mutator dialog's components.
   * @param {!Blockly.Block} containerBlock Root block in mutator.
   * @this Blockly.Block
   */
  compose: function(containerBlock) {
    var itemBlock = containerBlock.getInputTargetBlock('STACK');
    // Count number of inputs.
    var connections = [];
    while (itemBlock) {
      connections.push(itemBlock.valueConnection_);
      itemBlock = itemBlock.nextConnection &&
          itemBlock.nextConnection.targetBlock();
    }
    this.itemCount_ = connections.length;
    this.updateShape_();
    // Reconnect any child blocks.
    for (var i = 0; i < this.itemCount_; i++) {
      if (connections[i]) {
        this.getInput('ADD' + i).connection.connect(connections[i]);
      }
    }
  },
  /**
   * Store pointers to any connected child blocks.
   * @param {!Blockly.Block} containerBlock Root block in mutator.
   * @this Blockly.Block
   */
  saveConnections: function(containerBlock) {
    var itemBlock = containerBlock.getInputTargetBlock('STACK');
    var i = 0;
    while (itemBlock) {
      var input = this.getInput('ADD' + i);
      itemBlock.valueConnection_ = input && input.connection.targetConnection;
      i++;
      itemBlock = itemBlock.nextConnection &&
          itemBlock.nextConnection.targetBlock();
    }
  },
  /**
   * Modify this block to have the correct number of inputs.
   * @private
   * @this Blockly.Block
   */
  updateShape_: function() {
    // Delete everything.
    if (this.getInput('EMPTY')) {
      this.removeInput('EMPTY');
    } else {
      var i = 0;
      while (this.getInput('ADD' + i)) {
        this.removeInput('ADD' + i);
        i++;
      }
    }
    // Rebuild block.
    if (this.itemCount_ == 0) {
      this.appendDummyInput('EMPTY')
          .appendField(Blockly.Msg.LISTS_CREATE_EMPTY_TITLE);
    } else {
      for (var i = 0; i < this.itemCount_; i++) {
        var input = this.appendValueInput('ADD' + i);
        if (i == 0) {
          input.appendField(Blockly.Msg.LISTS_CREATE_WITH_INPUT_WITH);
        }
      }
    }
  }
};

Blockly.Blocks['lists_create_with_container'] = {
  /**
   * Mutator block for list container.
   * @this Blockly.Block
   */
  init: function() {
    this.setColour(Blockly.Variables.COLOUR.OPERATORS);
    this.appendDummyInput()
        .appendField(Blockly.Msg.LISTS_CREATE_WITH_CONTAINER_TITLE_ADD);
    this.appendStatementInput('STACK');
    this.setTooltip(Blockly.Msg.LISTS_CREATE_WITH_CONTAINER_TOOLTIP);
    this.contextMenu = false;
  }
};

Blockly.Blocks['lists_create_with_item'] = {
  /**
   * Mutator bolck for adding items.
   * @this Blockly.Block
   */
  init: function() {
    this.setColour(Blockly.Variables.COLOUR.OPERATORS);
    this.appendDummyInput()
        .appendField(Blockly.Msg.LISTS_CREATE_WITH_ITEM_TITLE);
    this.setPreviousStatement(true);
    this.setNextStatement(true);
    this.setTooltip(Blockly.Msg.LISTS_CREATE_WITH_ITEM_TOOLTIP);
    this.contextMenu = false;
  }
};

Blockly.Blocks['lists_repeat'] = {
  /**
   * Block for creating a list with one element repeated.
   * @this Blockly.Block
   */
  init: function() {
    this.jsonInit({
      "message0": Blockly.Msg.LISTS_REPEAT_TITLE,
      "args0": [
        {
          "type": "input_value",
          "name": "ITEM"
        },
        {
          "type": "input_value",
          "name": "NUM",
          "check": "Number"
        }
      ],
      "output": "Array",
      "colour": Blockly.Variables.COLOUR.OPERATORS,
      "tooltip": Blockly.Msg.LISTS_REPEAT_TOOLTIP,
      "helpUrl": Blockly.Msg.LISTS_REPEAT_HELPURL
    });
  }
};

Blockly.Blocks['lists_length'] = {
  /**
   * Block for list length.
   * @this Blockly.Block
   */
  init: function() {
    this.jsonInit({
      "message0": Blockly.Msg.LISTS_LENGTH_TITLE,
      "args0": [
        {
          "type": "input_value",
          "name": "VALUE",
          "check": ['String', 'Array']
        }
      ],
      "output": 'Number',
      "colour": Blockly.Variables.COLOUR.OPERATORS,
      "tooltip": Blockly.Msg.LISTS_LENGTH_TOOLTIP,
      "helpUrl": Blockly.Msg.LISTS_LENGTH_HELPURL
    });
  }
};

Blockly.Blocks['lists_isEmpty'] = {
  /**
   * Block for is the list empty?
   * @this Blockly.Block
   */
  init: function() {
    this.jsonInit({
      "message0": Blockly.Msg.LISTS_ISEMPTY_TITLE,
      "args0": [
        {
          "type": "input_value",
          "name": "VALUE",
          "check": ['String', 'Array']
        }
      ],
      "output": 'Boolean',
      "colour": Blockly.Variables.COLOUR.OPERATORS,
      "tooltip": Blockly.Msg.LISTS_ISEMPTY_TOOLTIP,
      "helpUrl": Blockly.Msg.LISTS_ISEMPTY_HELPURL
    });
  }
};

Blockly.Blocks['lists_indexOf'] = {
  /**
   * Block for finding an item in the list.
   * @this Blockly.Block
   */
  init: function() {
    var OPERATORS =
        [[Blockly.Msg.LISTS_INDEX_OF_FIRST, 'FIRST'],
         [Blockly.Msg.LISTS_INDEX_OF_LAST, 'LAST']];
    this.setHelpUrl(Blockly.Msg.LISTS_INDEX_OF_HELPURL);
    this.setColour(Blockly.Variables.COLOUR.OPERATORS);
    this.setOutput(true, 'Number');
    this.appendValueInput('VALUE')
        .setCheck('Array')
        .appendField(Blockly.Msg.LISTS_INDEX_OF_INPUT_IN_LIST);
    this.appendValueInput('FIND')
        .appendField(new Blockly.FieldDropdown(OPERATORS), 'END');
    this.setInputsInline(true);
    this.setTooltip(Blockly.Msg.LISTS_INDEX_OF_TOOLTIP);
  }
};

Blockly.Blocks['lists_getIndex'] = {
  /**
   * Block for getting element at index.
   * @this Blockly.Block
   */
  init: function() {
    var MODE =
        [[Blockly.Msg.LISTS_GET_INDEX_GET, 'GET'],
         [Blockly.Msg.LISTS_GET_INDEX_GET_REMOVE, 'GET_REMOVE'],
         [Blockly.Msg.LISTS_GET_INDEX_REMOVE, 'REMOVE']];
    this.WHERE_OPTIONS =
        [[Blockly.Msg.LISTS_GET_INDEX_FROM_START, 'FROM_START'],
         [Blockly.Msg.LISTS_GET_INDEX_FROM_END, 'FROM_END'],
         [Blockly.Msg.LISTS_GET_INDEX_FIRST, 'FIRST'],
         [Blockly.Msg.LISTS_GET_INDEX_LAST, 'LAST'],
         [Blockly.Msg.LISTS_GET_INDEX_RANDOM, 'RANDOM']];
    this.setHelpUrl(Blockly.Msg.LISTS_GET_INDEX_HELPURL);
    this.setColour(Blockly.Variables.COLOUR.OPERATORS);
    var modeMenu = new Blockly.FieldDropdown(MODE, function(value) {
      var isStatement = (value == 'REMOVE');
      this.sourceBlock_.updateStatement_(isStatement);
    });
    this.appendValueInput('VALUE')
        .setCheck('Array')
        .appendField(Blockly.Msg.LISTS_GET_INDEX_INPUT_IN_LIST);
    this.appendDummyInput()
        .appendField(modeMenu, 'MODE')
        .appendField('', 'SPACE');
    this.appendDummyInput('AT');
    if (Blockly.Msg.LISTS_GET_INDEX_TAIL) {
      this.appendDummyInput('TAIL')
          .appendField(Blockly.Msg.LISTS_GET_INDEX_TAIL);
    }
    this.setInputsInline(true);
    this.setOutput(true);
    this.updateAt_(true);
    // Assign 'this' to a variable for use in the tooltip closure below.
    var thisBlock = this;
    this.setTooltip(function() {
      var combo = thisBlock.getFieldValue('MODE') + '_' +
          thisBlock.getFieldValue('WHERE');
      return Blockly.Msg['LISTS_GET_INDEX_TOOLTIP_' + combo];
    });
  },
  /**
   * Create an object to represent mutation
   * @return {object} mutation data.
   * @this Blockly.Block
   */
  mutationToObject: function(){
    var isStatement = !this.outputConnection;
    var isAt = this.getInput('AT').type == Blockly.INPUT_VALUE;
    return {
      'statement':isStatement,
      'at':isAt
    };
  },
  /**
   * Parse mutation data to restore mutation.
   * @param {object} obj Mutation data object.
   * @this Blockly.Block
   */
  objectToMutation: function(obj){
    var isStatement = obj.statement;
    this.updateStatement_(isStatement);
    var isAt = obj.at;
    this.updateAt_(isAt);
  },
  /**
   * Create XML to represent whether the block is a statement or a value.
   * Also represent whether there is an 'AT' input.
   * @return {Element} XML storage element.
   * @this Blockly.Block
   */
  mutationToDom: function() {
    var container = document.createElement('mutation');
    var isStatement = !this.outputConnection;
    container.setAttribute('statement', isStatement);
    var isAt = this.getInput('AT').type == Blockly.INPUT_VALUE;
    container.setAttribute('at', isAt);
    return container;
  },
  /**
   * Parse XML to restore the 'AT' input.
   * @param {!Element} xmlElement XML storage element.
   * @this Blockly.Block
   */
  domToMutation: function(xmlElement) {
    // Note: Until January 2013 this block did not have mutations,
    // so 'statement' defaults to false and 'at' defaults to true.
    var isStatement = (xmlElement.getAttribute('statement') == 'true');
    this.updateStatement_(isStatement);
    var isAt = (xmlElement.getAttribute('at') != 'false');
    this.updateAt_(isAt);
  },
  /**
   * Switch between a value block and a statement block.
   * @param {boolean} newStatement True if the block should be a statement.
   *     False if the block should be a value.
   * @private
   * @this Blockly.Block
   */
  updateStatement_: function(newStatement) {
    var oldStatement = !this.outputConnection;
    if (newStatement != oldStatement) {
      this.unplug(true, true);
      if (newStatement) {
        this.setOutput(false);
        this.setPreviousStatement(true);
        this.setNextStatement(true);
      } else {
        this.setPreviousStatement(false);
        this.setNextStatement(false);
        this.setOutput(true);
      }
    }
  },
  /**
   * Create or delete an input for the numeric index.
   * @param {boolean} isAt True if the input should exist.
   * @private
   * @this Blockly.Block
   */
  updateAt_: function(isAt) {
    // Destroy old 'AT' and 'ORDINAL' inputs.
    this.removeInput('AT');
    this.removeInput('ORDINAL', true);
    // Create either a value 'AT' input or a dummy input.
    if (isAt) {
      this.appendValueInput('AT').setCheck('Number');
      if (Blockly.Msg.ORDINAL_NUMBER_SUFFIX) {
        this.appendDummyInput('ORDINAL')
            .appendField(Blockly.Msg.ORDINAL_NUMBER_SUFFIX);
      }
    } else {
      this.appendDummyInput('AT');
    }
    var menu = new Blockly.FieldDropdown(this.WHERE_OPTIONS, function(value) {
      var newAt = (value == 'FROM_START') || (value == 'FROM_END');
      // The 'isAt' variable is available due to this function being a closure.
      if (newAt != isAt) {
        var block = this.sourceBlock_;
        block.updateAt_(newAt);
        // This menu has been destroyed and replaced.  Update the replacement.
        block.setFieldValue(value, 'WHERE');
        return null;
      }
      return undefined;
    });
    this.getInput('AT').appendField(menu, 'WHERE');
    if (Blockly.Msg.LISTS_GET_INDEX_TAIL) {
      this.moveInputBefore('TAIL', null);
    }
  }
};

Blockly.Blocks['lists_setIndex'] = {
  /**
   * Block for setting the element at index.
   * @this Blockly.Block
   */
  init: function() {
    var MODE =
        [[Blockly.Msg.LISTS_SET_INDEX_SET, 'SET'],
         [Blockly.Msg.LISTS_SET_INDEX_INSERT, 'INSERT']];
    this.WHERE_OPTIONS =
        [[Blockly.Msg.LISTS_GET_INDEX_FROM_START, 'FROM_START'],
         [Blockly.Msg.LISTS_GET_INDEX_FROM_END, 'FROM_END'],
         [Blockly.Msg.LISTS_GET_INDEX_FIRST, 'FIRST'],
         [Blockly.Msg.LISTS_GET_INDEX_LAST, 'LAST'],
         [Blockly.Msg.LISTS_GET_INDEX_RANDOM, 'RANDOM']];
    this.setHelpUrl(Blockly.Msg.LISTS_SET_INDEX_HELPURL);
    this.setColour(Blockly.Variables.COLOUR.OPERATORS);
    this.appendValueInput('LIST')
        .setCheck('Array')
        .appendField(Blockly.Msg.LISTS_SET_INDEX_INPUT_IN_LIST);
    this.appendDummyInput()
        .appendField(new Blockly.FieldDropdown(MODE), 'MODE')
        .appendField('', 'SPACE');
    this.appendDummyInput('AT');
    this.appendValueInput('TO')
        .appendField(Blockly.Msg.LISTS_SET_INDEX_INPUT_TO);
    this.setInputsInline(true);
    this.setPreviousStatement(true);
    this.setNextStatement(true);
    this.setTooltip(Blockly.Msg.LISTS_SET_INDEX_TOOLTIP);
    this.updateAt_(true);
    // Assign 'this' to a variable for use in the tooltip closure below.
    var thisBlock = this;
    this.setTooltip(function() {
      var combo = thisBlock.getFieldValue('MODE') + '_' +
          thisBlock.getFieldValue('WHERE');
      return Blockly.Msg['LISTS_SET_INDEX_TOOLTIP_' + combo];
    });
  },
  /**
   * Create an object to represent mutation
   * @return {object} mutation data.
   * @this Blockly.Block
   */
  mutationToObject: function(){
    var isAt = this.getInput('AT').type == Blockly.INPUT_VALUE;
    return {
      'at':isAt
    };
  },
  /**
   * Parse mutation data to restore mutation.
   * @param {object} obj Mutation data object.
   * @this Blockly.Block
   */
  objectToMutation: function(obj){
    var isAt = obj.at;
    this.updateAt_(isAt);
  },
  /**
   * Create XML to represent whether there is an 'AT' input.
   * @return {Element} XML storage element.
   * @this Blockly.Block
   */
  mutationToDom: function() {
    var container = document.createElement('mutation');
    var isAt = this.getInput('AT').type == Blockly.INPUT_VALUE;
    container.setAttribute('at', isAt);
    return container;
  },
  /**
   * Parse XML to restore the 'AT' input.
   * @param {!Element} xmlElement XML storage element.
   * @this Blockly.Block
   */
  domToMutation: function(xmlElement) {
    // Note: Until January 2013 this block did not have mutations,
    // so 'at' defaults to true.
    var isAt = (xmlElement.getAttribute('at') != 'false');
    this.updateAt_(isAt);
  },
  /**
   * Create or delete an input for the numeric index.
   * @param {boolean} isAt True if the input should exist.
   * @private
   * @this Blockly.Block
   */
  updateAt_: function(isAt) {
    // Destroy old 'AT' and 'ORDINAL' input.
    this.removeInput('AT');
    this.removeInput('ORDINAL', true);
    // Create either a value 'AT' input or a dummy input.
    if (isAt) {
      this.appendValueInput('AT').setCheck('Number');
      if (Blockly.Msg.ORDINAL_NUMBER_SUFFIX) {
        this.appendDummyInput('ORDINAL')
            .appendField(Blockly.Msg.ORDINAL_NUMBER_SUFFIX);
      }
    } else {
      this.appendDummyInput('AT');
    }
    var menu = new Blockly.FieldDropdown(this.WHERE_OPTIONS, function(value) {
      var newAt = (value == 'FROM_START') || (value == 'FROM_END');
      // The 'isAt' variable is available due to this function being a closure.
      if (newAt != isAt) {
        var block = this.sourceBlock_;
        block.updateAt_(newAt);
        // This menu has been destroyed and replaced.  Update the replacement.
        block.setFieldValue(value, 'WHERE');
        return null;
      }
      return undefined;
    });
    this.moveInputBefore('AT', 'TO');
    if (this.getInput('ORDINAL')) {
      this.moveInputBefore('ORDINAL', 'TO');
    }

    this.getInput('AT').appendField(menu, 'WHERE');
  }
};

Blockly.Blocks['lists_getSublist'] = {
  /**
   * Block for getting sublist.
   * @this Blockly.Block
   */
  init: function() {
    this['WHERE_OPTIONS_1'] =
        [[Blockly.Msg.LISTS_GET_SUBLIST_START_FROM_START, 'FROM_START'],
         [Blockly.Msg.LISTS_GET_SUBLIST_START_FROM_END, 'FROM_END'],
         [Blockly.Msg.LISTS_GET_SUBLIST_START_FIRST, 'FIRST']];
    this['WHERE_OPTIONS_2'] =
        [[Blockly.Msg.LISTS_GET_SUBLIST_END_FROM_START, 'FROM_START'],
         [Blockly.Msg.LISTS_GET_SUBLIST_END_FROM_END, 'FROM_END'],
         [Blockly.Msg.LISTS_GET_SUBLIST_END_LAST, 'LAST']];
    this.setHelpUrl(Blockly.Msg.LISTS_GET_SUBLIST_HELPURL);
    this.setColour(Blockly.Variables.COLOUR.OPERATORS);
    this.appendValueInput('LIST')
        .setCheck('Array')
        .appendField(Blockly.Msg.LISTS_GET_SUBLIST_INPUT_IN_LIST);
    this.appendDummyInput('AT1');
    this.appendDummyInput('AT2');
    if (Blockly.Msg.LISTS_GET_SUBLIST_TAIL) {
      this.appendDummyInput('TAIL')
          .appendField(Blockly.Msg.LISTS_GET_SUBLIST_TAIL);
    }
    this.setInputsInline(true);
    this.setOutput(true, 'Array');
    this.updateAt_(1, true);
    this.updateAt_(2, true);
    this.setTooltip(Blockly.Msg.LISTS_GET_SUBLIST_TOOLTIP);
  },
  /**
   * Create an object to represent mutation
   * @return {object} mutation data.
   * @this Blockly.Block
   */
  mutationToObject: function(){
    var isAt1 = this.getInput('AT1').type == Blockly.INPUT_VALUE;
    var isAt2 = this.getInput('AT2').type == Blockly.INPUT_VALUE;
    return {
      'at1':isAt1,
      'at2':isAt2
    };
  },
  /**
   * Parse mutation data to restore mutation.
   * @param {object} obj Mutation data object.
   * @this Blockly.Block
   */
  objectToMutation: function(obj){
    var isAt1 = obj.at1;
    var isAt2 = obj.at2;
    this.updateAt_(1, isAt1);
    this.updateAt_(2, isAt2);
  },
  /**
   * Create XML to represent whether there are 'AT' inputs.
   * @return {Element} XML storage element.
   * @this Blockly.Block
   */
  mutationToDom: function() {
    var container = document.createElement('mutation');
    var isAt1 = this.getInput('AT1').type == Blockly.INPUT_VALUE;
    container.setAttribute('at1', isAt1);
    var isAt2 = this.getInput('AT2').type == Blockly.INPUT_VALUE;
    container.setAttribute('at2', isAt2);
    return container;
  },
  /**
   * Parse XML to restore the 'AT' inputs.
   * @param {!Element} xmlElement XML storage element.
   * @this Blockly.Block
   */
  domToMutation: function(xmlElement) {
    var isAt1 = (xmlElement.getAttribute('at1') == 'true');
    var isAt2 = (xmlElement.getAttribute('at2') == 'true');
    this.updateAt_(1, isAt1);
    this.updateAt_(2, isAt2);
  },
  /**
   * Create or delete an input for a numeric index.
   * This block has two such inputs, independant of each other.
   * @param {number} n Specify first or second input (1 or 2).
   * @param {boolean} isAt True if the input should exist.
   * @private
   * @this Blockly.Block
   */
  updateAt_: function(n, isAt) {
    // Create or delete an input for the numeric index.
    // Destroy old 'AT' and 'ORDINAL' inputs.
    this.removeInput('AT' + n);
    this.removeInput('ORDINAL' + n, true);
    // Create either a value 'AT' input or a dummy input.
    if (isAt) {
      this.appendValueInput('AT' + n).setCheck('Number');
      if (Blockly.Msg.ORDINAL_NUMBER_SUFFIX) {
        this.appendDummyInput('ORDINAL' + n)
            .appendField(Blockly.Msg.ORDINAL_NUMBER_SUFFIX);
      }
    } else {
      this.appendDummyInput('AT' + n);
    }
    var menu = new Blockly.FieldDropdown(this['WHERE_OPTIONS_' + n],
        function(value) {
      var newAt = (value == 'FROM_START') || (value == 'FROM_END');
      // The 'isAt' variable is available due to this function being a closure.
      if (newAt != isAt) {
        var block = this.sourceBlock_;
        block.updateAt_(n, newAt);
        // This menu has been destroyed and replaced.  Update the replacement.
        block.setFieldValue(value, 'WHERE' + n);
        return null;
      }
      return undefined;
    });
    this.getInput('AT' + n)
        .appendField(menu, 'WHERE' + n);
    if (n == 1) {
      this.moveInputBefore('AT1', 'AT2');
      if (this.getInput('ORDINAL1')) {
        this.moveInputBefore('ORDINAL1', 'AT2');
      }
    }
    if (Blockly.Msg.LISTS_GET_SUBLIST_TAIL) {
      this.moveInputBefore('TAIL', null);
    }
  }
};

Blockly.Blocks['lists_split'] = {
  /**
   * Block for splitting text into a list, or joining a list into text.
   * @this Blockly.Block
   */
  init: function() {
    // Assign 'this' to a variable for use in the closures below.
    var thisBlock = this;
    var dropdown = new Blockly.FieldDropdown(
        [[Blockly.Msg.LISTS_SPLIT_LIST_FROM_TEXT, 'SPLIT'],
         [Blockly.Msg.LISTS_SPLIT_TEXT_FROM_LIST, 'JOIN']],
        function(newMode) {
          thisBlock.updateType_(newMode);
        });
    this.setHelpUrl(Blockly.Msg.LISTS_SPLIT_HELPURL);
    this.setColour(Blockly.Variables.COLOUR.OPERATORS);
    this.appendValueInput('INPUT')
        .setCheck('String')
        .appendField(dropdown, 'MODE');
    this.appendValueInput('DELIM')
        .setCheck('String')
        .appendField(Blockly.Msg.LISTS_SPLIT_WITH_DELIMITER);
    this.setInputsInline(true);
    this.setOutput(true, 'Array');
    this.setTooltip(function() {
      var mode = thisBlock.getFieldValue('MODE');
      if (mode == 'SPLIT') {
        return Blockly.Msg.LISTS_SPLIT_TOOLTIP_SPLIT;
      } else if (mode == 'JOIN') {
        return Blockly.Msg.LISTS_SPLIT_TOOLTIP_JOIN;
      }
      throw 'Unknown mode: ' + mode;
    });
  },
  /**
   * Modify this block to have the correct input and output types.
   * @param {string} newMode Either 'SPLIT' or 'JOIN'.
   * @private
   * @this Blockly.Block
   */
  updateType_: function(newMode) {
    if (newMode == 'SPLIT') {
      this.outputConnection.setCheck('Array');
      this.getInput('INPUT').setCheck('String');
    } else {
      this.outputConnection.setCheck('String');
      this.getInput('INPUT').setCheck('Array');
    }
  },
  /**
   * Create an object to represent mutation
   * @return {object} mutation data.
   * @this Blockly.Block
   */
  mutationToObject: function(){
    return {
      'mode': this.getFieldValue('MODE')
    };
  },
  /**
   * Parse mutation data to restore mutation.
   * @param {object} obj Mutation data object.
   * @this Blockly.Block
   */
  objectToMutation: function(obj){
    this.updateType_( obj.mode );
  },
  /**
   * Create XML to represent the input and output types.
   * @return {!Element} XML storage element.
   * @this Blockly.Block
   */
  mutationToDom: function() {
    var container = document.createElement('mutation');
    container.setAttribute('mode', this.getFieldValue('MODE'));
    return container;
  },
  /**
   * Parse XML to restore the input and output types.
   * @param {!Element} xmlElement XML storage element.
   * @this Blockly.Block
   */
  domToMutation: function(xmlElement) {
    this.updateType_(xmlElement.getAttribute('mode'));
  }
};


Blockly.Blocks['lists_add'] = {
  init: function() {
    this.setHelpUrl( Blockly.Msg.LISTS_ADD_HELPURL );
    this.setColour(Blockly.Variables.COLOUR.OPERATORS);
    this.appendValueInput("LIST")
        .setCheck("Array")
        .appendField( Blockly.Msg.LISTS_ADD_MESSAGE_ONE );
    this.appendValueInput("INPUT")
        .appendField( Blockly.Msg.LISTS_ADD_MESSAGE_TWO );
    this.appendDummyInput()
        .appendField( Blockly.Msg.LISTS_ADD_MESSAGE_THREE )
        .appendField(new Blockly.FieldDropdown([
          ["end", "end"], 
          ["front", "front"]
        ]), "POSITION");
    this.setInputsInline(true);
    this.setPreviousStatement(true);
    this.setNextStatement(true);
    this.setTooltip( Blockly.Msg.LISTS_ADD_TOOLTIP );
  }
};