text: /**
   * @license
   * Copyright 2014 Google LLC
   * SPDX-License-Identifier: Apache-2.0
   */
  
  /**
   * @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_multiline'] = function(block) {
    // Text value.
    var code = Blockly.Dart.multiline_quote_(block.getFieldValue('TEXT'));
    var order = code.indexOf('+') != -1 ? Blockly.Dart.ORDER_ADDITIVE :
        Blockly.Dart.ORDER_ATOMIC;
    return [code, order];
  };
  
  Blockly.Dart['text_join'] = function(block) {
    // Create a string made up of any number of elements of any type.
    switch (block.itemCount_) {
      case 0:
        return ['\'\'', Blockly.Dart.ORDER_ATOMIC];
      case 1:
        var element = Blockly.Dart.valueToCode(block, 'ADD0',
                Blockly.Dart.ORDER_UNARY_POSTFIX) || '\'\'';
        var code = element + '.toString()';
        return [code, Blockly.Dart.ORDER_UNARY_POSTFIX];
      default:
        var elements = new Array(block.itemCount_);
        for (var i = 0; i < block.itemCount_; i++) {
          elements[i] = Blockly.Dart.valueToCode(block, 'ADD' + i,
                  Blockly.Dart.ORDER_NONE) || '\'\'';
        }
        var code = '[' + elements.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.nameDB_.getName(block.getFieldValue('VAR'),
        Blockly.VARIABLE_CATEGORY_NAME);
    var value = Blockly.Dart.valueToCode(block, 'TEXT',
        Blockly.Dart.ORDER_NONE) || '\'\'';
    return varName + ' = [' + varName + ', ' + value + '].join();\n';
  };
  
  Blockly.Dart['text_length'] = function(block) {
    // String or array length.
    var text = Blockly.Dart.valueToCode(block, 'VALUE',
        Blockly.Dart.ORDER_UNARY_POSTFIX) || '\'\'';
    return [text + '.length', Blockly.Dart.ORDER_UNARY_POSTFIX];
  };
  
  Blockly.Dart['text_isEmpty'] = function(block) {
    // Is the string null or array empty?
    var text = Blockly.Dart.valueToCode(block, 'VALUE',
        Blockly.Dart.ORDER_UNARY_POSTFIX) || '\'\'';
    return [text + '.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 substring = Blockly.Dart.valueToCode(block, 'FIND',
        Blockly.Dart.ORDER_NONE) || '\'\'';
    var text = Blockly.Dart.valueToCode(block, 'VALUE',
        Blockly.Dart.ORDER_UNARY_POSTFIX) || '\'\'';
    var code = text + '.' + operator + '(' + substring + ')';
    if (block.workspace.options.oneBasedIndex) {
      return [code + ' + 1', Blockly.Dart.ORDER_ADDITIVE];
    }
    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 textOrder = (where == 'FIRST' || where == 'FROM_START') ?
        Blockly.Dart.ORDER_UNARY_POSTFIX : Blockly.Dart.ORDER_NONE;
    var text = Blockly.Dart.valueToCode(block, 'VALUE', textOrder) || '\'\'';
    switch (where) {
      case 'FIRST':
        var code = text + '[0]';
        return [code, Blockly.Dart.ORDER_UNARY_POSTFIX];
      case 'FROM_START':
        var at = Blockly.Dart.getAdjusted(block, 'AT');
        var code = text + '[' + at + ']';
        return [code, Blockly.Dart.ORDER_UNARY_POSTFIX];
      case 'LAST':
        at = 1;
        // Fall through.
      case 'FROM_END':
        var at = Blockly.Dart.getAdjusted(block, 'AT', 1);
        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 Error('Unhandled option (text_charAt).');
  };
  
  Blockly.Dart['text_getSubstring'] = function(block) {
    // Get substring.
    var where1 = block.getFieldValue('WHERE1');
    var where2 = block.getFieldValue('WHERE2');
    var requiresLengthCall = (where1 != 'FROM_END' && where2 == 'FROM_START');
    var textOrder = requiresLengthCall ? Blockly.Dart.ORDER_UNARY_POSTFIX :
        Blockly.Dart.ORDER_NONE;
    var text = Blockly.Dart.valueToCode(block, 'STRING', textOrder) || '\'\'';
    if (where1 == 'FIRST' && where2 == 'LAST') {
      var code = text;
      return [code, Blockly.Dart.ORDER_NONE];
    } else if (text.match(/^'?\w+'?$/) || requiresLengthCall) {
      // If the text is a variable or literal or doesn't require a call for
      // length, don't generate a helper function.
      switch (where1) {
        case 'FROM_START':
          var at1 = Blockly.Dart.getAdjusted(block, 'AT1');
          break;
        case 'FROM_END':
          var at1 = Blockly.Dart.getAdjusted(block, 'AT1', 1, false,
              Blockly.Dart.ORDER_ADDITIVE);
          at1 = text + '.length - ' + at1;
          break;
        case 'FIRST':
          var at1 = '0';
          break;
        default:
          throw Error('Unhandled option (text_getSubstring).');
      }
      switch (where2) {
        case 'FROM_START':
          var at2 = Blockly.Dart.getAdjusted(block, 'AT2', 1);
          break;
        case 'FROM_END':
          var at2 = Blockly.Dart.getAdjusted(block, 'AT2', 0, false,
              Blockly.Dart.ORDER_ADDITIVE);
          at2 = text + '.length - ' + at2;
          break;
        case 'LAST':
          break;
        default:
          throw Error('Unhandled option (text_getSubstring).');
      }
      if (where2 == 'LAST') {
        var code = text + '.substring(' + at1 + ')';
      } else {
        var code = text + '.substring(' + at1 + ', ' + at2 + ')';
      }
    } else {
      var at1 = Blockly.Dart.getAdjusted(block, 'AT1');
      var at2 = Blockly.Dart.getAdjusted(block, 'AT2');
      var functionName = Blockly.Dart.provideFunction_(
          'text_get_substring',
          ['String ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
              '(String text, String where1, num at1, String where2, num at2) {',
           '  int getAt(String where, num at) {',
           '    if (where == \'FROM_END\') {',
           '      at = text.length - 1 - at;',
           '    } else if (where == \'FIRST\') {',
           '      at = 0;',
           '    } else if (where == \'LAST\') {',
           '      at = text.length - 1;',
           '    } else if (where != \'FROM_START\') {',
           '      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 textOrder = operator ? Blockly.Dart.ORDER_UNARY_POSTFIX :
        Blockly.Dart.ORDER_NONE;
    var text = Blockly.Dart.valueToCode(block, 'TEXT', textOrder) || '\'\'';
    if (operator) {
      // Upper and lower case are functions built into Dart.
      var code = text + 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 code = functionName + '(' + text + ')';
    }
    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 text = Blockly.Dart.valueToCode(block, 'TEXT',
        Blockly.Dart.ORDER_UNARY_POSTFIX) || '\'\'';
    return [text + operator, Blockly.Dart.ORDER_UNARY_POSTFIX];
  };
  
  Blockly.Dart['text_print'] = function(block) {
    // Print statement.
    var msg = Blockly.Dart.valueToCode(block, 'TEXT',
        Blockly.Dart.ORDER_NONE) || '\'\'';
    return 'print(' + msg + ');\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'];
  
  Blockly.Dart['text_count'] = function(block) {
    var text = Blockly.Dart.valueToCode(block, 'TEXT',
        Blockly.Dart.ORDER_NONE) || '\'\'';
    var sub = Blockly.Dart.valueToCode(block, 'SUB',
        Blockly.Dart.ORDER_NONE) || '\'\'';
    // Substring count is not a native Dart function.  Define one.
    var functionName = Blockly.Dart.provideFunction_(
        'text_count',
        ['int ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
          '(String haystack, String needle) {',
          '  if (needle.length == 0) {',
          '    return haystack.length + 1;',
          '  }',
          '  int index = 0;',
          '  int count = 0;',
          '  while (index != -1) {',
          '    index = haystack.indexOf(needle, index);',
          '    if (index != -1) {',
          '      count++;',
          '     index += needle.length;',
          '    }',
          '  }',
          '  return count;',
          '}']);
    var code = functionName + '(' + text + ', ' + sub + ')';
    return [code, Blockly.Dart.ORDER_UNARY_POSTFIX];
  };
  
  Blockly.Dart['text_replace'] = function(block) {
    var text = Blockly.Dart.valueToCode(block, 'TEXT',
        Blockly.Dart.ORDER_UNARY_POSTFIX) || '\'\'';
    var from = Blockly.Dart.valueToCode(block, 'FROM',
        Blockly.Dart.ORDER_NONE) || '\'\'';
    var to = Blockly.Dart.valueToCode(block, 'TO',
        Blockly.Dart.ORDER_NONE) || '\'\'';
    var code = text + '.replaceAll(' + from + ', ' + to + ')';
    return [code, Blockly.Dart.ORDER_UNARY_POSTFIX];
  };
  
  Blockly.Dart['text_reverse'] = function(block) {
    // There isn't a sensible way to do this in Dart. See:
    // http://stackoverflow.com/a/21613700/3529104
    // Implementing something is possibly better than not implementing anything?
    var text = Blockly.Dart.valueToCode(block, 'TEXT',
        Blockly.Dart.ORDER_UNARY_POSTFIX) || '\'\'';
    var code = 'new String.fromCharCodes(' + text + '.runes.toList().reversed)';
    return [code, Blockly.Dart.ORDER_UNARY_PREFIX];
  };
  