text: /*
   *  Copyright 2015 Adobe Systems Incorporated. All rights reserved.
   *  This file is licensed 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 REPRESENTATIONS
   *  OF ANY KIND, either express or implied. See the License for the specific language
   *  governing permissions and limitations under the License.
   */
  
  'use strict';
  
  var put = require('put');
  var binary = require('binary');
  var logger = require('../../logging').getLogger('smb');
  
  var ntstatus = require('../../ntstatus');
  var SMB2 = require('../constants');
  var utils = require('../../utils');
  
  /**
   * SMB2_NEGOTIATE (0x0000): Negotiate protocol dialect.
   *
   * @param {Object} msg - an SMB message object
   * @param {Number} commandId - the command id
   * @param {Buffer} body - the command specific message body
   * @param {Object} related - context for related operations (null for unrelated operation)
   * @param {Long} related.sessionId - sessionId
   * @param {Number} related.treeId - treeId
   * @param {Object} related.fileId - fileId
   * @param {Object} connection - an SMBConnection instance
   * @param {Object} server - an SMBServer instance
   * @param {Function} cb callback called with the command's result
   * @param {Object} cb.result - an object with the command's result
   *                             or null if the handler already sent the response and
   *                             no further processing is required by the caller
   * @param {Number} cb.result.status
   * @param {Buffer} cb.result.body
   */
  function handle(msg, commandId, body, related, connection, server, cb) {
    var parser = binary.parse(body);
    var dialects = [];
    var params = parser.word16le('structureSize') // 0x0024 (fixed according to spec)
      .word16le('dialectCount')
      .word16le('securityMode')
      .skip(2)  // Reserved
      .word32le('capabilities')
      .buffer('clientGuid', 16)
      .word32le('negotiateContextOffset')
      .word16le('negotiateContextCount')
      .skip(2)  // Reserved2
      .buffer('dialectsRaw', 2 * parser.vars['dialectCount'])
      .vars;
  
    var off = 0;
    params.dialects = [];
    var dialectsString = '';
    while (params.dialects.length < params.dialectCount) {
      var dialectCode = params.dialectsRaw.readUInt16LE(off);
      off += 2;
      params.dialects.push(dialectCode);
      if (dialectsString !== '') {
        dialectsString += ', ';
      }
      dialectsString += '0x' + dialectCode.toString(16);
    }
  
    logger.debug('[%s] dialects: [ %s ]', SMB2.COMMAND_TO_STRING[commandId].toUpperCase(), dialectsString);
  
    var result;
  
    // target SMB 2.1 for now
    var targetDialect;
    if (params.dialects.indexOf(SMB2.SMB_2_1_0) > -1) {
      targetDialect = SMB2.SMB_2_1_0;
    } else if (params.dialects.indexOf(SMB2.SMB_2_0_2) > -1) {
      targetDialect = SMB2.SMB_2_0_2;
    } else {
      result = {
        status: ntstatus.STATUS_NOT_IMPLEMENTED,
        body: utils.EMPTY_BUFFER
      };
      process.nextTick(function () { cb(result); });
    }
  
    var systemTime = utils.systemToSMBTime(Date.now());
    var startTime = utils.systemToSMBTime(server.getStartTime());
    var securityBuffer = utils.EMPTY_BUFFER;
    var out = put();
    out.word16le(0x0041)  // StructureSize (fixed according to spec)
      .word16le(0) // SecurityMode
      .word16le(targetDialect) // DialectRevision
      .word16le(0)  // NegotiateContextCount/Reserved
      .put(server.getGuid())  // ServerGuid
      .word32le(SMB2.GLOBAL_CAP_DFS | SMB2.GLOBAL_CAP_LARGE_MTU) // Capabilities
      .word32le(0x00100000) // MaxTransactSize
      .word32le(0x00100000) // MaxReadSize
      .word32le(0x00100000) // MaxWriteSize
      .word32le(systemTime.getLowBitsUnsigned())  // SystemTime
      .word32le(systemTime.getHighBitsUnsigned())
      .word32le(startTime.getLowBitsUnsigned())  // ServerStartTime
      .word32le(startTime.getHighBitsUnsigned())
      .word16le(SMB2.HEADER_LENGTH + 64)  // SecurityBufferOffset
      .word16le(securityBuffer.length)  // SecurityBufferLength
      .word32le(0)  // NegotiateContextOffset/Reserved2
      .put(securityBuffer); // SecurityBuffer
  
    // return result
    result = {
      status: ntstatus.STATUS_SUCCESS,
      body: out.buffer()
    };
    process.nextTick(function () { cb(result); });
  }
  
  module.exports = handle;
  