text: /**
   * Copyright Yaco Sistemas S.L. 2011.
   *
   * 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.
   */
  
  const log4js = require('log4js');
  const Changeset = require('ep_etherpad-lite/static/js/Changeset');
  const contentcollector = require('ep_etherpad-lite/static/js/contentcollector');
  const cheerio = require('cheerio');
  const rehype = require('rehype');
  const minifyWhitespace = require('rehype-minify-whitespace');
  
  exports.setPadHTML = async (pad, html) => {
    const apiLogger = log4js.getLogger('ImportHtml');
  
    rehype()
      .use(minifyWhitespace, {newlines: false})
      .process(html, (err, output) => {
        html = String(output);
      });
  
    const $ = cheerio.load(html);
  
    // Appends a line break, used by Etherpad to ensure a caret is available
    // below the last line of an import
    $('body').append('<p></p>');
  
    const doc = $('html')[0];
    apiLogger.debug('html:');
    apiLogger.debug(html);
  
    // Convert a dom tree into a list of lines and attribute liens
    // using the content collector object
    const cc = contentcollector.makeContentCollector(true, null, pad.pool);
    try {
      // we use a try here because if the HTML is bad it will blow up
      cc.collectContent(doc);
    } catch (e) {
      apiLogger.warn('HTML was not properly formed', e);
  
      // don't process the HTML because it was bad
      throw e;
    }
  
    const result = cc.finish();
  
    apiLogger.debug('Lines:');
  
    let i;
    for (i = 0; i < result.lines.length; i++) {
      apiLogger.debug(`Line ${i + 1} text: ${result.lines[i]}`);
      apiLogger.debug(`Line ${i + 1} attributes: ${result.lineAttribs[i]}`);
    }
  
    // Get the new plain text and its attributes
    const newText = result.lines.join('\n');
    apiLogger.debug('newText:');
    apiLogger.debug(newText);
    const newAttribs = `${result.lineAttribs.join('|1+1')}|1+1`;
  
    function eachAttribRun(attribs, func /* (startInNewText, endInNewText, attribs)*/) {
      const attribsIter = Changeset.opIterator(attribs);
      let textIndex = 0;
      const newTextStart = 0;
      const newTextEnd = newText.length;
      while (attribsIter.hasNext()) {
        const op = attribsIter.next();
        const nextIndex = textIndex + op.chars;
        if (!(nextIndex <= newTextStart || textIndex >= newTextEnd)) {
          func(Math.max(newTextStart, textIndex), Math.min(newTextEnd, nextIndex), op.attribs);
        }
        textIndex = nextIndex;
      }
    }
  
    // create a new changeset with a helper builder object
    const builder = Changeset.builder(1);
  
    // assemble each line into the builder
    eachAttribRun(newAttribs, (start, end, attribs) => {
      builder.insert(newText.substring(start, end), attribs);
    });
  
    // the changeset is ready!
    const theChangeset = builder.toString();
  
    apiLogger.debug(`The changeset: ${theChangeset}`);
    await Promise.all([
      pad.setText('\n'),
      pad.appendRevision(theChangeset),
    ]);
  };
  