text: 'use strict';
  
  const OperationBase = require('./operation').OperationBase;
  const applyRetryableWrites = require('../utils').applyRetryableWrites;
  const applyWriteConcern = require('../utils').applyWriteConcern;
  const decorateWithCollation = require('../utils').decorateWithCollation;
  const executeCommand = require('./db_ops').executeCommand;
  const formattedOrderClause = require('../utils').formattedOrderClause;
  const handleCallback = require('../utils').handleCallback;
  const ReadPreference = require('../core').ReadPreference;
  const maxWireVersion = require('../core/utils').maxWireVersion;
  const MongoError = require('../error').MongoError;
  
  class FindAndModifyOperation extends OperationBase {
    constructor(collection, query, sort, doc, options) {
      super(options);
  
      this.collection = collection;
      this.query = query;
      this.sort = sort;
      this.doc = doc;
    }
  
    execute(callback) {
      const coll = this.collection;
      const query = this.query;
      const sort = formattedOrderClause(this.sort);
      const doc = this.doc;
      let options = this.options;
  
      // Create findAndModify command object
      const queryObject = {
        findAndModify: coll.collectionName,
        query: query
      };
  
      if (sort) {
        queryObject.sort = sort;
      }
  
      queryObject.new = options.new ? true : false;
      queryObject.remove = options.remove ? true : false;
      queryObject.upsert = options.upsert ? true : false;
  
      const projection = options.projection || options.fields;
  
      if (projection) {
        queryObject.fields = projection;
      }
  
      if (options.arrayFilters) {
        queryObject.arrayFilters = options.arrayFilters;
      }
  
      if (doc && !options.remove) {
        queryObject.update = doc;
      }
  
      if (options.maxTimeMS) queryObject.maxTimeMS = options.maxTimeMS;
  
      // Either use override on the function, or go back to default on either the collection
      // level or db
      options.serializeFunctions = options.serializeFunctions || coll.s.serializeFunctions;
  
      // No check on the documents
      options.checkKeys = false;
  
      // Final options for retryable writes and write concern
      options = applyRetryableWrites(options, coll.s.db);
      options = applyWriteConcern(options, { db: coll.s.db, collection: coll }, options);
  
      // Decorate the findAndModify command with the write Concern
      if (options.writeConcern) {
        queryObject.writeConcern = options.writeConcern;
      }
  
      // Have we specified bypassDocumentValidation
      if (options.bypassDocumentValidation === true) {
        queryObject.bypassDocumentValidation = options.bypassDocumentValidation;
      }
  
      options.readPreference = ReadPreference.primary;
  
      // Have we specified collation
      try {
        decorateWithCollation(queryObject, coll, options);
      } catch (err) {
        return callback(err, null);
      }
  
      if (options.hint) {
        // TODO: once this method becomes a CommandOperationV2 we will have the server
        // in place to check.
        const unacknowledgedWrite = options.writeConcern && options.writeConcern.w === 0;
        if (unacknowledgedWrite || maxWireVersion(coll.s.topology) < 8) {
          callback(
            new MongoError('The current topology does not support a hint on findAndModify commands')
          );
  
          return;
        }
  
        queryObject.hint = options.hint;
      }
  
      // Execute the command
      executeCommand(coll.s.db, queryObject, options, (err, result) => {
        if (err) return handleCallback(callback, err, null);
  
        return handleCallback(callback, null, result);
      });
    }
  }
  
  module.exports = FindAndModifyOperation;
  