$scope.myHub = new hub("chatHub", {
  listeners: {},
  methods: []
})

 $scope.myHub.promise.done(function () {
     $scope.myHub.init();
     $scope.myHub.promise.done(function () { });
  });

 $scope.requestChat = function (msg) {
                if (!defaultCustomerUserName) {
                    //گرفتن کاربر لاگین شده
                    //ما از آرایه تصادفی استفاده میکنیم
                    var nameDefaultArray = [
                        'حسین', 'حسن', 'علی', 'عباس', 'زهرا', 'سمیه'
                    ];
                    defaultCustomerUserName=nameDefaultArray[Math.floor(Math.random() * nameDefaultArray.length)];
                }
                var userName = defaultCustomerUserName;
                if (!$scope.chatId) {
                    $scope.chatId = sessionStorage.getItem(chatKey);
                    $http.get("http://ipinfo.io")
                      .success(function (response) {
                          $scope.myHub.logVisit(response.city, response.country, msg, userName);
                      }).error(function (e, status, headers, config) {
                          $scope.myHub.logVisit("Tehran", "Ir", msg, userName)
                      });
                    $scope.myHub.requestChat(msg);
                    $scope.chatTitle = $scope.options.waitingForOperator;
                    $scope.pendingRequestChat = true;
                } else {
                    $scope.myHub.clientSendMessage(msg, userName);
                };
                $scope.message = "";
            };

public void AcceptRequestChat(string customerConnectionId, string body, string userName)
        {
            var agent = FindAgent(Context.ConnectionId);
            var session = _chatSessions.FirstOrDefault(item => item.Key.Equals(agent.Key));
            if (session == null)
            {
                _chatSessions.Add(new ChatSessionVm
                {
                    Key = agent.Key,
                    Value = new List<string> { customerConnectionId }
                });
            }
            else
            {
                session.Value.Add(customerConnectionId);
            }
            Clients.Client(Context.ConnectionId).agentChat(customerConnectionId, body, userName);
            Clients.Client(customerConnectionId).clientChat(customerConnectionId, agent.Value.UserName);
            foreach (var item in _agents.Where(item => item.Value.IsOnline))
            {
                Clients.Client(item.Value.ConnectionId).refreshChatWith(agent.Value.UserName, customerConnectionId);
            }
       var session = _db.Sessions.Add(new Session
            {
                AgentName = agent.Key,
                CustomerName = userName,
                CreatedDateTime = DateTime.Now
            });
            _db.SaveChanges();

            var message = new Message
            {
                CreationTime = DateTime.Now,
                Sender = agent.Key,
                Receiver = userName,
                body=body,
                Session = session
            };
            _db.Messages.Add(message);
            _db.SaveChanges();
        }

public void CloseChat(string id)
        {
            var findAgent = FindAgent(Context.ConnectionId);
            var session = _chatSessions.FirstOrDefault(item => item.Value.Contains(id));
            if (session == null) return;
            Clients.Client(id).clientAddMessage(findAgent.Key, "مکالمه شما با کارشناس مربوطه به اتمام رسیده است");

            foreach (var agent in _agents)
            {
                Clients.Client(agent.Value.ConnectionId).refreshLeaveChat(agent.Value.UserName, id);
            }
            _chatSessions.Remove(session);
        }

   public void EngageVisitor(string newAgentId, string cumtomerId, string customerName,string clientSessionId)
        {
            #region remove session of current agent
            var currentAgent = FindAgent(Context.ConnectionId);
            var currentSession = _chatSessions.FirstOrDefault(item => item.Value.Contains(cumtomerId));
            if (currentSession != null)
            {
                _chatSessions.Remove(currentSession);
            }
            #endregion

            #region add  session to new agent
            var newAgent = FindAgent(newAgentId);
            var newSession = _chatSessions.FirstOrDefault(item => item.Key.Equals(newAgent.Key));
            if (newSession == null)
            {
                _chatSessions.Add(new ChatSessionVm
                {
                    Key = newAgent.Key,
                    Value = new List<string> { cumtomerId }
                });
            }
            else
            {
                newSession.Value.Add(cumtomerId);
            }
            #endregion

            Clients.Client(currentAgent.Value.ConnectionId).addMessage(cumtomerId, newAgent.Key,
                "ادامه مکالمه به کارشناس  " + newAgent.Key + "مقابل  منتقل شد");
            Clients.Client(newAgentId).addMessage(cumtomerId, currentAgent.Key,
                "لطفا مکالمه را ادامه دهید.با تشکر");

            Clients.Client(cumtomerId).clientAddMessage(newAgent.Value.UserName,
                "مکالمه شما با کارشناس زیر برقرار گردید" + newAgent.Key);

            var session = _db.Sessions.FirstOrDefault
                (item => item.AgentName.Equals(currentAgent.Value.UserName)
                 && item.CustomerName.Equals(customerName));
            if (session != null)
            {
                var sessionId = session.Id;
                var messages = _db.Messages.Where(item => item.Session.Id.Equals(sessionId));
                var result = JsonConvert.SerializeObject(messages, new Formatting(), _settings);
                Clients.Client(newAgentId).visitorSwitchConversation
                    (Context.ConnectionId, customerName, result, clientSessionId);
            }
            foreach (var item in _agents.Where(item => item.Value.IsOnline))
            {
                Clients.Client(item.Value.ConnectionId).refreshChatWith(newAgent.Value.UserName, cumtomerId);
            }
            _db.Sessions.Add(new Session
            {
                AgentName = newAgent.Key,
                CustomerName = customerName,
                CreatedDateTime = DateTime.Now,
                Parent = _db.Sessions.Where(item => item.AgentName.Equals(currentAgent.Key)
                      && item.CustomerName.Equals(customerName)).OrderByDescending(item => item.Id).FirstOrDefault()
            });
            _db.SaveChanges();
        }

   [HubName("chatHub")]
    public class ChatHub : Microsoft.AspNet.SignalR.Hub
    {
        private readonly ApplicationDbContext _db = new ApplicationDbContext();
        private static ConcurrentDictionary<string, UserInformation> _agents;
        private static List<ChatSessionVm> _chatSessions;
        private readonly JsonSerializerSettings _settings = new JsonSerializerSettings
        {
            ContractResolver = new CamelCasePropertyNamesContractResolver(),
            ReferenceLoopHandling = ReferenceLoopHandling.Ignore
        };
        public void Init()
        {
            _chatSessions = _chatSessions ?? (_chatSessions = new List<ChatSessionVm>());
            _agents = _agents ?? (_agents = new ConcurrentDictionary<string, UserInformation>());
            Clients.Caller.onlineStatus(_agents.Count(x => x.Value.IsOnline) > 0);
        }
        public void AgentConnect(string userName)
        {
            //ما برای ساده کردن مقایسه ساده ای انجام دادیم فقط کاربر حسین یا علی میتواند کارشناس باشد
            if (userName == "hossein" || userName == "ali")
            {
                var agent = new UserInformation();
                if (_agents.Any(item => item.Key == userName))
                {
                    agent = _agents[userName];
                    agent.ConnectionId = Context.ConnectionId;
                }
                else
                {
                    agent.ConnectionId = Context.ConnectionId;
                    agent.UserName = userName;
                    agent.IsOnline = true;
                    _agents.TryAdd(userName, agent);

                }
                Clients.Caller.loginResult(true, agent.ConnectionId, agent.UserName);
                Clients.All.onlineStatus(_agents.Count(x => x.Value.IsOnline) > 0);
            }
            else
            {
                Clients.Caller.loginResult(false, null, null);
            }
        }
        public void AgentChangeStatus(bool status)
        {
            var agent = _agents.FirstOrDefault(x => x.Value.ConnectionId == Context.ConnectionId).Value;
            if (agent == null) return;
            agent.IsOnline = status;
            Clients.All.onlineStatus(_agents.Count(x => x.Value.IsOnline) > 0);
        }
        public void LogVisit(string city, string country, string firstComment, string userName)
        {
            foreach (var agent in _agents)
            {
                Clients.Client(agent.Value.ConnectionId).newVisit(userName, city, country, null, Context.ConnectionId, firstComment);
            }
        }
        public void AcceptRequestChat(string customerConnectionId, string body, string userName)
        {
            var agent = FindAgent(Context.ConnectionId);
            var session = _chatSessions.FirstOrDefault(item => item.Key.Equals(agent.Key));
            if (session == null)
            {
                _chatSessions.Add(new ChatSessionVm
                {
                    Key = agent.Key,
                    Value = new List<string> { customerConnectionId }
                });
            }
            else
            {
                session.Value.Add(customerConnectionId);
            }
            Clients.Client(Context.ConnectionId).agentChat(customerConnectionId, body, userName);
            Clients.Client(customerConnectionId).clientChat(customerConnectionId, agent.Value.UserName);
            foreach (var item in _agents.Where(item => item.Value.IsOnline))
            {
                Clients.Client(item.Value.ConnectionId).refreshChatWith(agent.Value.UserName, customerConnectionId);
            }
            _db.Sessions.Add(new Session
            {
                AgentName = agent.Key,
                CustomerName = userName,
                CreatedDateTime = DateTime.Now
            });
            _db.SaveChanges();

            var message = new Message
            {
                CreationTime = DateTime.Now,
                Sender = agent.Key,
                Receiver = userName,
                Body = body,
                //ConnectionId = _agents.FirstOrDefault(item => item.Value.UserName == userName).Key,
                Session = _db.Sessions.OrderByDescending(item => item.Id)
                .FirstOrDefault(item => item.AgentName.Equals(agent.Key) && item.CustomerName.Equals(userName))
            };
            _db.Messages.Add(message);
            _db.SaveChanges();
        }
        public void GetAgentHistoryChat(string userName)
        {
            var dic = new Dictionary<int, int>();
            var lenght = 0;
            var chats = _db.Sessions.OrderBy(item => item.Id).Include(item => item.Parent)
                .Where(item => item.AgentName.Equals(userName)).ToList();

            foreach (var session in chats)
            {
                Result(session, ref lenght);
                dic.Add(session.Id, lenght);
                lenght = 0;
            }
            if (!chats.Any()) return;

            var historyResult = chats.Select(item => new AgentViewModel
            {
                Id = item.Id,
                CustomerName = item.CustomerName,
                Date = item.CreatedDateTime,
                Lenght = dic.Any(di => di.Key.Equals(item.Id)) ? dic.FirstOrDefault(di => di.Key.Equals(item.Id)).Value : 0,
            }).OrderByDescending(item => item.Id).ToList();
            Clients.Caller.receiveHistory(JsonConvert.SerializeObject(historyResult, new Formatting(), _settings));
        }
        public void DetailsSessoinMessage(int sessionId, string agentId)
        {
            var session = _db.Sessions.FirstOrDefault(item => item.Id.Equals(sessionId));
            if (session == null) return;
            var list = new List<Message>();
            GetAllMessages(session, list);
            var result = JsonConvert.SerializeObject(list.OrderBy(item => item.Id), new Formatting(), _settings);
            Clients.Client(Context.ConnectionId).detailsHistory(result);
        }
        public void ClientSendMessage(string body, string userName)
        {
            var session = _chatSessions.FirstOrDefault(item => item.Value.Contains(Context.ConnectionId));
            if (session == null || session.Key == null) return;
            var agentId = _agents.FirstOrDefault(item => item.Key.Equals(session.Key)).Value.ConnectionId;
            Clients.Caller.clientAddMessage("من", body);
            Clients.Client(agentId).addMessage(Context.ConnectionId, userName, body);
            var message = new Message
            {
                Sender = FindAgent(agentId).Key,
                Receiver = userName,
                Body = body,
                CreationTime = DateTime.Now,
                Session = FindSession(userName, FindAgent(agentId).Key)
            };
            _db.Messages.Add(message);
            _db.SaveChanges();
        }
        public void AgentSendMessage(string id, string body, string userName)
        {
            var agent = FindAgent(Context.ConnectionId);
            Clients.Caller.addMessage(id, agent.Value.UserName, body);
            Clients.Client(id).clientAddMessage(agent.Value.UserName, body);
            var message = new Message
            {
                Sender = agent.Key,
                Receiver = userName,
                Body = body,
                Session = FindSession(agent.Key, userName),
                CreationTime = DateTime.Now
            };
            _db.Messages.Add(message);
            _db.SaveChanges();
        }
        public void CloseChat(string id)
        {
            var findAgent = FindAgent(Context.ConnectionId);
            var session = _chatSessions.FirstOrDefault(item => item.Value.Contains(id));
            if (session == null) return;
            Clients.Client(id).clientAddMessage(findAgent.Key, "مکالمه شما با کارشناس مربوطه به اتمام رسیده است");

            foreach (var agent in _agents)
            {
                Clients.Client(agent.Value.ConnectionId).refreshLeaveChat(agent.Value.UserName, id);
            }
            _chatSessions.Remove(session);
        }
        public void RequestChat(string message)
        {
            Clients.Caller.clientAddMessage("من", message);
        }
        public void EngageVisitor(string newAgentId, string cumtomerId, string customerName,string clientSessionId)
        {
            #region remove session of current agent
            var currentAgent = FindAgent(Context.ConnectionId);
            var currentSession = _chatSessions.FirstOrDefault(item => item.Value.Contains(cumtomerId));
            if (currentSession != null)
            {
                _chatSessions.Remove(currentSession);
            }
            #endregion

            #region add  session to new agent
            var newAgent = FindAgent(newAgentId);
            var newSession = _chatSessions.FirstOrDefault(item => item.Key.Equals(newAgent.Key));
            if (newSession == null)
            {
                _chatSessions.Add(new ChatSessionVm
                {
                    Key = newAgent.Key,
                    Value = new List<string> { cumtomerId }
                });
            }
            else
            {
                newSession.Value.Add(cumtomerId);
            }
            #endregion

            Clients.Client(currentAgent.Value.ConnectionId).addMessage(cumtomerId, newAgent.Key,
                "ادامه مکالمه به کارشناس  " + newAgent.Key + "مقابل  منتقل شد");
            Clients.Client(newAgentId).addMessage(cumtomerId, currentAgent.Key,
                "لطفا مکالمه را ادامه دهید.با تشکر");

            Clients.Client(cumtomerId).clientAddMessage(newAgent.Value.UserName,
                "مکالمه شما با کارشناس زیر برقرار گردید" + newAgent.Key);

            var session = _db.Sessions.FirstOrDefault
                (item => item.AgentName.Equals(currentAgent.Value.UserName)
                 && item.CustomerName.Equals(customerName));
            if (session != null)
            {
                var sessionId = session.Id;
                var messages = _db.Messages.Where(item => item.Session.Id.Equals(sessionId));
                var result = JsonConvert.SerializeObject(messages, new Formatting(), _settings);
                Clients.Client(newAgentId).visitorSwitchConversation
                    (Context.ConnectionId, customerName, result, clientSessionId);
            }
            foreach (var item in _agents.Where(item => item.Value.IsOnline))
            {
                Clients.Client(item.Value.ConnectionId).refreshChatWith(newAgent.Value.UserName, cumtomerId);
            }
            _db.Sessions.Add(new Session
            {
                AgentName = newAgent.Key,
                CustomerName = customerName,
                CreatedDateTime = DateTime.Now,
                Parent = _db.Sessions.Where(item => item.AgentName.Equals(currentAgent.Key)
                      && item.CustomerName.Equals(customerName)).OrderByDescending(item => item.Id).FirstOrDefault()
            });
            _db.SaveChanges();
        }
        public void ShowAgentList()
        {
            Clients.Caller.agentList(_agents.ToList());
        }
        public override Task OnDisconnected(bool stopCalled)
        {
            var id = Context.ConnectionId;
            var isAgent = _agents != null && _agents.Any(item => item.Value.ConnectionId.Equals(id));
            if (isAgent)
            {
                UserInformation agent;
                var currentAgentConnectionId = FindAgent(id).Key;
                if (currentAgentConnectionId == null)
                    return base.OnDisconnected(stopCalled);
                if (_chatSessions.Any())
                {
                    var sessions = _chatSessions.FirstOrDefault(item => item.Key.Equals(currentAgentConnectionId));
                    //اطلاع دادن به تمام کاربرانی که در حال مکالمه با کارشناس هستند
                    if (sessions != null)
                    {
                        var result = sessions.Value.ToList();
                        for (var i = 0; i < result.Count(); i++)
                        {
                            var localId = result[i];
                            Clients.Client(localId).clientAddMessage(currentAgentConnectionId, "ارتباط شما با مشاور مورد نظر قطع شده است");
                        }
                    }
                }
                _agents.TryRemove(currentAgentConnectionId, out agent);
                Clients.All.onlineStatus(_agents.Count(x => x.Value.IsOnline) > 0);
                Clients.Client(id).loginResult(false, null, null);
            }
            else
            {
                if (_chatSessions == null ||
                    !_chatSessions.Any(item => item.Value.Contains(id)
                        && _agents == null))
                    return base.OnDisconnected(stopCalled);

                var session = _chatSessions.FirstOrDefault(item => item.Value.Contains(id));
                if (session == null)
                    return base.OnDisconnected(stopCalled);

                var agentName = session.Key;
                var agent = _agents.FirstOrDefault(item => item.Key.Equals(agentName));
                if (agent.Key != null)
                {
                    Clients.Client(agent.Value.ConnectionId).addMessage(id, "کاربر", "اتصال با کاربر قطع شده است");
                }
            }
            return base.OnDisconnected(stopCalled);
        }


        private KeyValuePair<string, UserInformation> FindAgent(string connectionId)
        {
            return _agents.FirstOrDefault(item => item.Value.ConnectionId.Equals(connectionId));
        }
        private Session FindSession(string key, string userName)
        {
            return _db.Sessions.Where(item => item.AgentName.Equals(key) && item.CustomerName.Equals(userName))
                .OrderByDescending(item => item.Id).FirstOrDefault();
        }
        private static void Result(Session parent, ref int lenght)
        {
            while (true)
            {
                if (parent == null)
                    return;
                lenght += parent.Messages.Count();
                parent = parent.Parent;
            }
        }
        private static List<Message> GetAllMessages(Session node, List<Message> list)
        {
            if (node == null) return null;
            list.AddRange(node.Messages);
            if (node.Parent != null)
            {
                GetAllMessages(node.Parent, list);
            }
            return null;
        }
    }

<div>
    <div>
        <h2>
            خوش آمدید
            <span ng-bind="agent.name">
            </span>
            <a ng-click="changeAgentStatus()">
                <i ng-if="changeStatus==null"
                   data-placement="bottom"
                   data-trigger="hover "
                   bs-tooltip="options.lock"></i>
                <i ng-if="changeStatus==true"
                   data-placement="bottom"
                   data-trigger="hover"
                   bs-tooltip="options.unlock"></i>
            </a>
        </h2>
        <div style="float: left">
            <a ng-click="setAlarm()">
                <i ng-show="alarmStatus"
                   data-placement="bottom"
                   data-trigger="hover "
                   bs-tooltip="options.alarmOn"></i>

                <i ng-show="!alarmStatus"
                   data-placement="bottom"
                   data-trigger="hover "
                   bs-tooltip="options.alarmOff"></i>
            </a>
            <!--<a data-placement="bottom"
               data-trigger="hover "
               bs-tooltip="options.conversion" ng-click="showHistory()"><i></i></a>-->

            <a data-placement="bottom"
               data-trigger="hover "
               bs-tooltip="options.edit"><i></i><span></span></a>

            <a data-placement="bottom"
               data-trigger="hover "
               bs-tooltip="options.setting"><i></i></a>

            <a data-placement="bottom"
               data-trigger="hover "
               bs-tooltip="options.signOut" ng-click="LeaveChat()"><i></i><span></span></a>
        </div>
    </div>
    <div>
        <div>
            <div id="chat-content">
                <div>
                    <ul>
                        <li>
                            <a showtab href="#online-list">آنلاین</a>
                        </li>
                        <li>
                            <a ng-click="showHistory()" showtab href="#conversation">آرشیو گفتگوها</a>
                        </li>
                    </ul>
                    <div>
                        <div id="online-list">
                            <div>
                                <h2>
                                    <i></i><span></span>
                                    <span>نمایش آنلاین مراجعه ها</span>
                                </h2>
                            </div>
                            <div>
                                <div id="agent-chat">
                                    <div id="real-time-visits">
                                        <table id="current-visits">
                                            <thead>
                                                <tr>
                                                    <th>نام کاربر</th>
                                                    <th>زمان اولین تقاضا</th>
                                                    <th>منطقه</th>
                                                    <th>پاسخ</th>
                                                </tr>
                                            </thead>
                                            <tbody>
                                                <tr id="{{item.connectionId}}" ng-animate="animate" ng-repeat="item in customerVisit ">
                                                    <td ng-bind="item.userName"></td>
                                                    <td>
                                                        <span time-ago title="{{item.date}}"></span>
                                                    </td>
                                                    <td>
                                                        <span ng-bind="item.country"></span> /<span ng-bind="item.city"> </span>
                                                    </td>
                                                    <td>
                                                        <a style="cursor: pointer" ng-if="item.chatWith== null"
                                                           ng-click="acceptRequestChat(item.connectionId,item.firstComment,item.userName)">
                                                            شروع مکالمه
                                                        </a>
                                                        <span ng-if="item.chatWith ">
                                                            وضعیت:
                                                            <span>در حال مکالمه با</span>
                                                            <span ng-bind="item.chatWith"></span>
                                                            <a ng-show="item.chatWith==agent.name"
                                                              
                                                               ng-click="selectVisitor(item.connectionId,item.userName,item.connectionId)">
                                                                انتقال مکالمه
                                                            </a>
                                                        </span>
                                                        <ul ng-repeat="session in chatSessions track by $index" style="padding:0px;">
                                                            <li ng-if="session.id==item.connectionId" id="{{session.id}}">
                                                                <div>
                                                                    <p>
                                                                        تاریخ شروع مکالمه:
                                                                        <span time-ago title="{{session.date}}"></span>
                                                                    </p>
                                                                    <p>
                                                                        تعداد پیام ها:
                                                                        <span ng-bind="session.length"></span>
                                                                    </p>
                                                                </div>
                                                                <p>
                                                                    <a ng-click="detailsChat(session.id,session.userName)">جزییات </a>
                                                                    <a ng-click="closeChat(session.id)">
                                                                        خاتمه عملیات
                                                                    </a>
                                                                </p>
                                                            </li>
                                                        </ul>
                                                    </td>
                                                </tr>
                                            </tbody>
                                        </table>
                                    </div>
                                </div>
                            </div>
                        </div>
                        <div id="conversation">
                            <div>
                                <h2>
                                    <i></i><span></span>
                                    <span>آرشیو گفتگوهای </span>
                                    {{agent.name}}
                                </h2>
                            </div>
                            <div>
                                <div>
                                    <table id="current-visits">
                                        <thead>
                                            <tr>
                                                <th>شناسه مشتری</th>
                                                <th>نام مشتری</th>
                                                <th>تعداد محاوره ها</th>
                                                <th>تاریخ</th>
                                                <th>جزئیات</th>
                                            </tr>
                                        </thead>
                                        <tbody>
                                            <tr ng-repeat="item in agentHistory track by $index">
                                                <td ng-bind="item.id"></td>
                                                <td ng-bind="item.customerName"></td>
                                                <th ng-bind="item.lenght"></th>
                                                <td><span time-ago title="{{item.date}}"></span></td>
                                                <th>
                                                    <ang-click="detailsChatHistory(item.id)" >مشاهده جزییات گفتگو</a>
                                                </th>
                                            </tr>
                                        </tbody>
                                    </table>
                                </div>
                            </div>
                        </div>
                    </div>
                </div>
            </div>
        </div>
    </div>
    <div id="detailsAgentHistory" tabindex="-1" role="dialog" aria-labelledby="cmdLabel" aria-hidden="true">
        <div>
            <div>
                <div>
                    <div>
                        <button type="button" data-dismiss="modal" aria-hidden="true">×</button>
                    </div>
                    <h2>
                        <span></span>تاریخچه گفتگو
                    </h2>
                </div>
                <div>
                    <div style="display: block">
                        <ul ng-repeat="item in historyMsg">
                            <li>
                                <span ng-bind="item.name" ng-style="setdirectionClass(item.name)">
                                </span>
                                <span ng-style="setdirectionClass(item.name)">
                                    <span ng-class="setArrowClass(item.name)"></span>
                                    <span time-ago title="{{item.date}}"></span>
                                    <span>
                                        <p ng-bind-html="item.msg | smilies"></p>
                                    </span>
                                </span>
                            </li>
                        </ul>
                    </div>

                </div>
            </div>
        </div>
    </div>
    <div id="agentList" tabindex="-1" role="dialog" aria-labelledby="cmdLabel" aria-hidden="true">
        <div>
            <div>
                <div>
                    <div>
                        <button type="button" data-dismiss="modal" aria-hidden="true">×</button>
                    </div>
                    <h2>
                        <span></span>لیست تمام کارشناسان
                    </h2>
                </div>
                <div>
                    <div style="display: block;">
                        <div ng-show="agentList.length==0">
                            کارشناس آنلاینی وجود ندارد
                        </div>
                        <ul ng-repeat="item in agentList">
                            <li>
                                <span>
                                    <a ng-click="engageVisitor(item.id)">{{item.name}}</a>
                                </span>
                            </li>
                        </ul>
                    </div>
                </div>
            </div>
        </div>
    </div>
    <div id="agentUserChat"  tabindex="-1" role="dialog" aria-labelledby="cmdLabel" aria-hidden="true">
        <div>
            <div>
                <div>
                    <div>
                        <button type="button" data-dismiss="modal" aria-hidden="true">×</button>
                    </div>
                    <h2>
                        <span></span>گفتگو
                    </h2>
                </div>
                <div>
                    <div>
                        <div>
                            <div style="display: block;">
                                <label>شروع چت در </label>:
                                <span ng-bind="dateStartChat"></span>

                                <ul>
                                    <li ng-repeat="item in agentUserMsgs">
                                        <span ng-bind="item.name" ng-style="setdirectionClass(item.name)">

                                        </span>
                                        <span ng-style="setdirectionClass(item.name)">
                                            <span ng-class="setArrowClass(item.name)"></span>
                                            <span time-ago title="{{item.date}}"></span>

                                            <span>
                                                <p ng-bind-html="item.msg | smilies"></p>
                                            </span>
                                        </span>
                                    </li>
                                </ul>
                                <div>
                                    <div>
                                        <textarea id="post-msg" ng-model="msg" placeholder="متن خود را وارد نمایید" style="overflow: hidden; word-wrap: break-word; resize: horizontal; height: 80px; max-width: 100%"></textarea>
                                        <span smilies-selector="msg" smilies-placement="right" smilies-title="Smilies"></span>
                                    </div>
                                    <div style="text-align: center; margin-top: 5px">
                                        <button ng-click="agentMsgToUser(msg)">ارسال</button>
                                    </div>
                                </div>
                            </div>
                        </div>
                    </div>
                </div>
            </div>
        </div>
    </div>
</div>

public static unsafe void HtmlEncode(string value, TextWriter output)
{
  int index = IndexOfHtmlEncodingChars(value, 0);
  if (index == -1)
  {
    output.Write(value);
    return;
  }
  int cch = value.Length - index;
  fixed (char* str = value)
  {
    char* pch = str;
    while (index-- > 0)
    {
      output.Write(*pch++);
    }
    while (cch-- > 0)
    {
      char ch = *pch++;
      if (ch <= '>')
      {
        switch (ch)
        {
          case '<':
            output.Write("&lt;");
            break;
          case '>':
            output.Write("&gt;");
            break;
          case '"':
            output.Write("&quot;");
            break;
          case '\'':
            output.Write("&#39;");
            break;
          case '&':
            output.Write("&amp;");
            break;
          default:
            output.Write(ch);
            break;
        }
      }
      else if (ch >= 160 && ch < 256)
      {
        // The seemingly arbitrary 160 comes from RFC 
        output.Write("&#");
        output.Write(((int)ch).ToString(NumberFormatInfo.InvariantInfo));
        output.Write(';');
      }
      else
      {
        output.Write(ch);
      }
    }
  }
}
private static unsafe int IndexOfHtmlEncodingChars(string s, int startPos)
{
  int cch = s.Length - startPos;
  fixed (char* str = s)
  {
    for (char* pch = &str[startPos]; cch > 0; pch++, cch--)
    {
      char ch = *pch;
      if (ch <= '>')
      {
        switch (ch)
        {
          case '<':
          case '>':
          case '"':
          case '\'':
          case '&':
            return s.Length - cch;
        }
      }
      else if (ch >= 160 && ch < 256)
      {
        return s.Length - cch;
      }
    }
  }
  return -1;
}

<div id="log"></div>
<script type="text/javascript">
  var element = document.getElementById('log');
  element.innerText = '<html> encoding </html>';
  console.log(element.innerHTML);
</script>

<html> encoding </html>

console.log(String.htmlEncode("<html>"));
//result:   &lt;html&gt;

console.log("<html>".htmlEncode());
//result:    &lt;html&gt;

String.htmlDecode = function (s) {
  var el = document.createElement("div");
  el.innerHTML = s || '';
  return el.innerText;
};

String.prototype.htmlDecode = function () {
  var el = document.createElement("div");
  el.innerHTML = this.toString();
  return el.innerText;
};

String.htmlDecode = function (s) {
  return $('<div/>').html(s).text();
};

String.prototype.htmlDecode = function () {
  return $('<div/>').html(this.toString()).text();
};

var value = "a \n b";

String.htmlDecode(String.htmlEncode(myString)) === myString;

var myString = "<HTML>";
String.htmlDecode(String.htmlEncode(myString)) === myString;
// result:   true
// --------------------------------------------------------------------------
myString = "<اچ تی ام ال>";
String.htmlDecode(String.htmlEncode(myString)) === myString;
// result:   true

myString = "a \r b";
String.htmlDecode(String.htmlEncode(myString)) === myString;
// result:   false

console.log(escape(String.htmlDecode('\r'))); // result:    %0A  :  it is url encode of character '\n'
console.log(escape(String.htmlDecode('\n'))); // result:    %0A
console.log(escape(String.htmlDecode('\r\n'))); // result:    %0A