text: /**
   * @license
   * Visual Blocks Language
   *
   * Copyright 2014 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 Generating Dart for text blocks.
   * @author fraser@google.com (Neil Fraser)
   */
  'use strict';
  
  goog.provide('Blockly.Dart.texts');
  
  goog.require('Blockly.Dart');
  
  
  Blockly.Dart.addReservedWords('Html,Math');
  
  Blockly.Dart['text'] = function(block) {
    // Text value.
    var code = Blockly.Dart.quote_(block.getFieldValue('TEXT'));
    return [code, Blockly.Dart.ORDER_ATOMIC];
  };
  
  Blockly.Dart['text_join'] = function(block) {
    // Create a string made up of any number of elements of any type.
    var code;
    if (block.itemCount_ == 0) {
      return ['\'\'', Blockly.Dart.ORDER_ATOMIC];
    } else if (block.itemCount_ == 1) {
      var argument0 = Blockly.Dart.valueToCode(block, 'ADD0',
          Blockly.Dart.ORDER_UNARY_POSTFIX) || '\'\'';
      code = argument0 + '.toString()';
      return [code, Blockly.Dart.ORDER_UNARY_POSTFIX];
    } else {
      code = new Array(block.itemCount_);
      for (var n = 0; n < block.itemCount_; n++) {
        code[n] = Blockly.Dart.valueToCode(block, 'ADD' + n,
            Blockly.Dart.ORDER_NONE) || '\'\'';
      }
      code = '[' + code.join(',') + '].join()';
      return [code, Blockly.Dart.ORDER_UNARY_POSTFIX];
    }
  };
  
  Blockly.Dart['text_append'] = function(block) {
    // Append to a variable in place.
    var varName = Blockly.Dart.variableDB_.getName(block.getFieldValue('VAR'),
        Blockly.Variables.NAME_TYPE);
    var argument0 = Blockly.Dart.valueToCode(block, 'TEXT',
        Blockly.Dart.ORDER_UNARY_POSTFIX) || '\'\'';
    return varName + ' = [' + varName + ', ' + argument0 + '].join();\n';
  };
  
  Blockly.Dart['text_length'] = function(block) {
    // String length.
    var argument0 = Blockly.Dart.valueToCode(block, 'VALUE',
        Blockly.Dart.ORDER_UNARY_POSTFIX) || '\'\'';
    return [argument0 + '.length', Blockly.Dart.ORDER_UNARY_POSTFIX];
  };
  
  Blockly.Dart['text_isEmpty'] = function(block) {
    // Is the string null?
    var argument0 = Blockly.Dart.valueToCode(block, 'VALUE',
        Blockly.Dart.ORDER_UNARY_POSTFIX) || '\'\'';
    return [argument0 + '.isEmpty', Blockly.Dart.ORDER_UNARY_POSTFIX];
  };
  
  Blockly.Dart['text_indexOf'] = function(block) {
    // Search the text for a substring.
    var operator = block.getFieldValue('END') == 'FIRST' ?
        'indexOf' : 'lastIndexOf';
    var argument0 = Blockly.Dart.valueToCode(block, 'FIND',
        Blockly.Dart.ORDER_NONE) || '\'\'';
    var argument1 = Blockly.Dart.valueToCode(block, 'VALUE',
        Blockly.Dart.ORDER_UNARY_POSTFIX) || '\'\'';
    var code = argument1 + '.' + operator + '(' + argument0 + ') + 1';
    return [code, Blockly.Dart.ORDER_UNARY_POSTFIX];
  };
  
  Blockly.Dart['text_charAt'] = function(block) {
    // Get letter at index.
    // Note: Until January 2013 this block did not have the WHERE input.
    var where = block.getFieldValue('WHERE') || 'FROM_START';
    var at = Blockly.Dart.valueToCode(block, 'AT',
        Blockly.Dart.ORDER_NONE) || '1';
    var text = Blockly.Dart.valueToCode(block, 'VALUE',
        Blockly.Dart.ORDER_UNARY_POSTFIX) || '\'\'';
    switch (where) {
      case 'FIRST':
        var code = text + '[0]';
        return [code, Blockly.Dart.ORDER_UNARY_POSTFIX];
      case 'FROM_START':
        // Blockly uses one-based indicies.
        if (at.match(/^-?\d+$/)) {
          // If the index is a naked number, decrement it right now.
          at = parseInt(at, 10) - 1;
        } else {
          // If the index is dynamic, decrement it in code.
          at += ' - 1';
        }
        var code = text + '[' + at + ']';
        return [code, Blockly.Dart.ORDER_UNARY_POSTFIX];
      case 'LAST':
        at = 1;
        // Fall through.
      case 'FROM_END':
        var functionName = Blockly.Dart.provideFunction_(
            'text_get_from_end',
            [ 'String ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
                '(String text, num x) {',
              '  return text[text.length - x];',
              '}']);
        code = functionName + '(' + text + ', ' + at + ')';
        return [code, Blockly.Dart.ORDER_UNARY_POSTFIX];
      case 'RANDOM':
        Blockly.Dart.definitions_['import_dart_math'] =
            'import \'dart:math\' as Math;';
        var functionName = Blockly.Dart.provideFunction_(
            'text_random_letter',
            [ 'String ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
                '(String text) {',
              '  int x = new Math.Random().nextInt(text.length);',
              '  return text[x];',
              '}']);
        code = functionName + '(' + text + ')';
        return [code, Blockly.Dart.ORDER_UNARY_POSTFIX];
    }
    throw 'Unhandled option (text_charAt).';
  };
  
  Blockly.Dart['text_getSubstring'] = function(block) {
    // Get substring.
    var text = Blockly.Dart.valueToCode(block, 'STRING',
        Blockly.Dart.ORDER_UNARY_POSTFIX) || '\'\'';
    var where1 = block.getFieldValue('WHERE1');
    var where2 = block.getFieldValue('WHERE2');
    var at1 = Blockly.Dart.valueToCode(block, 'AT1',
        Blockly.Dart.ORDER_NONE) || '1';
    var at2 = Blockly.Dart.valueToCode(block, 'AT2',
        Blockly.Dart.ORDER_NONE) || '1';
    if (where1 == 'FIRST' && where2 == 'LAST') {
      var code = text;
    } else {
      var functionName = Blockly.Dart.provideFunction_(
          'text_get_substring',
          [ 'function ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
              '(text, where1, at1, where2, at2) {',
            '  function getAt(where, at) {',
            '    if (where == \'FROM_START\') {',
            '      at--;',
            '    } else if (where == \'FROM_END\') {',
            '      at = text.length - at;',
            '    } else if (where == \'FIRST\') {',
            '      at = 0;',
            '    } else if (where == \'LAST\') {',
            '      at = text.length - 1;',
            '    } else {',
            '      throw \'Unhandled option (text_getSubstring).\';',
            '    }',
            '    return at;',
            '  }',
            '  at1 = getAt(where1, at1);',
            '  at2 = getAt(where2, at2) + 1;',
            '  return text.substring(at1, at2);',
            '}']);
      var code = functionName + '(' + text + ', \'' +
          where1 + '\', ' + at1 + ', \'' + where2 + '\', ' + at2 + ')';
    }
    return [code, Blockly.Dart.ORDER_UNARY_POSTFIX];
  };
  
  Blockly.Dart['text_changeCase'] = function(block) {
    // Change capitalization.
    var OPERATORS = {
      'UPPERCASE': '.toUpperCase()',
      'LOWERCASE': '.toLowerCase()',
      'TITLECASE': null
    };
    var operator = OPERATORS[block.getFieldValue('CASE')];
    var code;
    if (operator) {
      // Upper and lower case are functions built into Dart.
      var argument0 = Blockly.Dart.valueToCode(block, 'TEXT',
          Blockly.Dart.ORDER_UNARY_POSTFIX) || '\'\'';
      code = argument0 + operator;
    } else {
      // Title case is not a native Dart function.  Define one.
      var functionName = Blockly.Dart.provideFunction_(
          'text_toTitleCase',
          [ 'String ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
              '(String str) {',
            '  RegExp exp = new RegExp(r\'\\b\');',
            '  List<String> list = str.split(exp);',
            '  final title = new StringBuffer();',
            '  for (String part in list) {',
            '    if (part.length > 0) {',
            '      title.write(part[0].toUpperCase());',
            '      if (part.length > 0) {',
            '        title.write(part.substring(1).toLowerCase());',
            '      }',
            '    }',
            '  }',
            '  return title.toString();',
            '}']);
      var argument0 = Blockly.Dart.valueToCode(block, 'TEXT',
          Blockly.Dart.ORDER_NONE) || '\'\'';
      code = functionName + '(' + argument0 + ')';
    }
    return [code, Blockly.Dart.ORDER_UNARY_POSTFIX];
  };
  
  Blockly.Dart['text_trim'] = function(block) {
    // Trim spaces.
    var OPERATORS = {
      'LEFT': '.replaceFirst(new RegExp(r\'^\\s+\'), \'\')',
      'RIGHT': '.replaceFirst(new RegExp(r\'\\s+$\'), \'\')',
      'BOTH': '.trim()'
    };
    var operator = OPERATORS[block.getFieldValue('MODE')];
    var argument0 = Blockly.Dart.valueToCode(block, 'TEXT',
        Blockly.Dart.ORDER_UNARY_POSTFIX) || '\'\'';
    return [argument0 + operator, Blockly.Dart.ORDER_UNARY_POSTFIX];
  };
  
  Blockly.Dart['text_print'] = function(block) {
    // Print statement.
    var argument0 = Blockly.Dart.valueToCode(block, 'TEXT',
        Blockly.Dart.ORDER_NONE) || '\'\'';
    return 'print(' + argument0 + ');\n';
  };
  
  Blockly.Dart['text_prompt_ext'] = function(block) {
    // Prompt function.
    Blockly.Dart.definitions_['import_dart_html'] =
        'import \'dart:html\' as Html;';
    if (block.getField('TEXT')) {
      // Internal message.
      var msg = Blockly.Dart.quote_(block.getFieldValue('TEXT'));
    } else {
      // External message.
      var msg = Blockly.Dart.valueToCode(block, 'TEXT',
          Blockly.Dart.ORDER_NONE) || '\'\'';
    }
    var code = 'Html.window.prompt(' + msg + ', \'\')';
    var toNumber = block.getFieldValue('TYPE') == 'NUMBER';
    if (toNumber) {
      Blockly.Dart.definitions_['import_dart_math'] =
          'import \'dart:math\' as Math;';
      code = 'Math.parseDouble(' + code + ')';
    }
    return [code, Blockly.Dart.ORDER_UNARY_POSTFIX];
  };
  
  Blockly.Dart['text_prompt'] = Blockly.Dart['text_prompt_ext'];
  