const annotationChanged = async (annotations, action, options) => {
    if (options.imported) return;

    const xfdfString = await annotManager.exportAnnotCommand();
    const parser = new DOMParser();
    const commandData = parser.parseFromString(xfdfString, 'text/xml');
    const addedAnnots = commandData.getElementsByTagName('add')[0];
    const modifiedAnnots = commandData.getElementsByTagName('modify')[0];
    const deletedAnnots = commandData.getElementsByTagName('delete')[0];

    let data = {
      session_id: user.session_id,
      uid: user.uid,
      socket_token: user.socket_token,
      publisherId,
      offline: false,
      annotations: []
    };

    // Added annotations
    addedAnnots.childNodes.forEach(child => {
      const annotation = generateAnnotationObject(child, 'add');
      if (annotation) data.annotations.push(annotation);
    });

    // Modified annotations
    modifiedAnnots.childNodes.forEach(child => {
      const annotation = generateAnnotationObject(child, 'modify');
      if (annotation) data.annotations.push(annotation);
    });

    // Deleted annotations
    deletedAnnots.childNodes.forEach(child => {
      const annotation = generateAnnotationObject(child, 'delete');
      if (annotation) data.annotations.push(annotation);
    });

    socket.emit('updateAnnotations', data);
    debug.info('Socket updateAnnotations sent');
  };

  const generateAnnotationObject = (annotation, action) => {
    if (annotation.nodeType === annotation.TEXT_NODE) return false;

    return {
      id:
        annotation.getAttribute('name') || annotation.childNodes[0].textContent,
      page_number: parseInt(annotation.getAttribute('page')) + 1,
      xfdf: serializer.serializeToString(annotation),
      issue_id: parseInt(mif.issue_id),
      updated: Date.now(),
      deleted: action === 'delete'
    };
  };

  const updateAnnotations = annotations => {
    debug.info('Received updateAnnotations socket');

    annotations.forEach(async ({ id, deleted, xfdf }) => {
      const annotation = await annotManager.getAnnotationById(id);
      if (annotation && deleted) {
        return annotManager.deleteAnnotation(annotation);
      }

      const action = annotation ? 'modify' : 'add';
      const xfdfCmd = convertToXfdf(xfdf, action);
      const annotationInstances = await annotManager.importAnnotCommand(
        xfdfCmd
      );
      return annotManager.drawAnnotationsFromList(annotationInstances);
    });
  };