text: // Licensed to the Apache Software Foundation (ASF) under one
  // or more contributor license agreements.  See the NOTICE file
  // distributed with this work for additional information
  // regarding copyright ownership.  The ASF licenses this file
  // to you 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.
  
  'use strict';
  
  module.exports = (function () {
  
      var fs = require('fs');
      var path = require('path');
  
      function stripFrontMatter (text) {
  
          // get and replace front matter if it's there
          // NOTE:
          //      String.replace() replaces only the first occurrence
          //      of a string, which is what we want
          var rawFrontMatterString = getRawFrontMatterString(text);
          if (rawFrontMatterString !== null) {
              return text.replace(rawFrontMatterString, '');
          }
  
          return text;
      }
  
      function getFrontMatterString (text) {
          var rawFrontMatterString = getRawFrontMatterString(text);
          if (rawFrontMatterString !== null) {
  
              // strip out front matter markers
              var frontMatterString = rawFrontMatterString.replace(/^---\s*$/gm, '');
              return frontMatterString;
          }
  
          return null;
      }
  
      function setFrontMatterString (text, frontMatterString) {
          var textOnly = stripFrontMatter(text);
          var newText = '---\n' + frontMatterString + '---\n\n' + textOnly;
          return newText;
      }
  
      function getRawFrontMatterString (text) {
          // NOTE:
          //      [\s\S]  matches all characters
          //      *?      non-greedy *-match
          var match = text.match(/^(---\s*\r?\n[\s\S]*?\r?\n---\s*\r?\n)[\s\S]*$/);
          if (match === null) {
              return null;
          }
          return match[1];
      }
  
      function listdirsSync (root) {
          return fs.readdirSync(root).filter(function (fileName) {
              return fs.statSync(path.join(root, fileName)).isDirectory();
          });
      }
  
      function tocfileName (language, version, suffix) {
          var versionSlug = version.replace(/\./g, '-');
          if (suffix) {
              suffix = '-' + suffix;
          } else {
              suffix = '';
          }
          return language + '_' + versionSlug + suffix + '.yml';
      }
  
      function srcTocfileName (language, version) {
          return tocfileName(language, version, 'src');
      }
  
      function genTocfileName (language, version) {
          return tocfileName(language, version, 'gen');
      }
  
      function mergeObjects (a, b) {
          var c = {};
  
          // NOTE: b's properties override a's properties
          Object.keys(a).forEach(function (key) {
              c[key] = a[key];
          });
          Object.keys(b).forEach(function (key) {
              c[key] = b[key];
          });
          return c;
      }
  
      function generatedBy (scriptName) {
          return '# WARNING: This file is generated by ' + path.basename(scriptName);
      }
  
      return {
          stripFrontMatter: stripFrontMatter,
          getFrontMatterString: getFrontMatterString,
          setFrontMatterString: setFrontMatterString,
          getRawFrontMatterString: getRawFrontMatterString,
          listdirsSync: listdirsSync,
          tocfileName: tocfileName,
          srcTocfileName: srcTocfileName,
          genTocfileName: genTocfileName,
          mergeObjects: mergeObjects,
          generatedBy: generatedBy
      };
  })();
  