/*
 *  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 logger = require('winston').loggers.get('smb');

var ntstatus = require('../../ntstatus');
var SMB = require('../constants');
var utils = require('../../utils');

/**
 * SMB_COM_LOGOFF_ANDX (0x74): User logoff with AndX chaining.
 *
 * @param {Object} msg - an SMB message object
 * @param {Number} commandId - the command id
 * @param {Buffer} commandParams - the command parameters
 * @param {Buffer} commandData - the command data
 * @param {Number} commandParamsOffset - the command parameters offset within the SMB
 * @param {Number} commandDataOffset - the command data offset within the SMB
 * @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 params and data
 *                             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.params
 * @param {Buffer} cb.result.data
 */
function handle(msg, commandId, commandParams, commandData, commandParamsOffset, commandDataOffset, connection, server, cb) {

  logger.debug('[%s] uid: %d', SMB.COMMAND_TO_STRING[commandId].toUpperCase(), msg.header.uid);

  var result;

  var session = server.getSession(msg.header.uid);
  if (!session) {
    result = {
      status: ntstatus.STATUS_SMB_BAD_UID,
      params: utils.EMPTY_BUFFER,
      data: utils.EMPTY_BUFFER
    };
    process.nextTick(function () { cb(result); });
    return;
  }

  session.logoff();

  // params
  var out = put();
  out.word8(commandParams.readUInt8(0)) // andX next cmd id
    .word8(0) // andX reserved
    .word16le(commandParams.readUInt16LE(2))  // andX offset (needs to be recalculated by caller!)
    .word16le(0);  // action
  var params = out.buffer();

  // return result
  result = {
    status: ntstatus.STATUS_SUCCESS,
    params: params,
    data: utils.EMPTY_BUFFER
  };
  process.nextTick(function () { cb(result); });
}

module.exports = handle;