using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;

using BeWo.Data;
using BeWo.Data.Access;
using BeWo.Data.Entities;

using BS.Shared;


namespace BeWoChatServer
{
    public class Server
    {
        // Fehlercodes zwischen 1000 und 1499

        private static readonly object _Lock = string.Empty;

        private static readonly Dictionary<Socket, long> clientList = new Dictionary<Socket, long>();
        protected static Socket serverSocket;

        private static AsyncCallback asyncCallback;

        private static int clientCount;

        public static void Main(string[] args)
        {
            try
            {
                Console.WriteLine(DateTime.Now + ": Starte Server");

                serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

                var server = new IPEndPoint(IPAddress.Any, 5000);

                serverSocket.Bind(server);
                serverSocket.Listen(4);

                serverSocket.BeginAccept(OnClientConnected, null);

                while (true) { }
            }
            catch (Exception e)
            {
                WriteErrorMessageToConsole(e.Message, e.StackTrace);
            }
        }

        public static void OnClientConnected(IAsyncResult asyncResult)
        {
            try
            {
                var workerSocket = serverSocket.EndAccept(asyncResult);

                Interlocked.Increment(ref clientCount);

                clientList.Add(workerSocket, 0);

                Console.WriteLine(DateTime.Now + ": Client hinzugefügt");

                WaitForClientData(workerSocket, "", 0, 0);

                serverSocket.BeginAccept(OnClientConnected, null);
            }
            catch (SocketException e)
            {
                WriteErrorMessageToConsole(e.Message, e.StackTrace);
            }
        }

        public static void WaitForClientData(Socket socket, string clientName, long oid, long recipientPersonOid)
        {
            try
            {
                if (asyncCallback == null)
                {
                    asyncCallback = OnReceiveData;
                }

                var packet = new Packet(socket, clientName, oid, recipientPersonOid);

                socket.BeginReceive(packet.DataBuffer, 0, packet.DataBuffer.Length, SocketFlags.None, asyncCallback, packet);
            }
            catch (Exception e)
            {
                WriteErrorMessageToConsole(e.Message, e.StackTrace);
            }
        }

        public static void OnReceiveData(IAsyncResult asyncResult)
        {
            var dataPacket = (Packet) asyncResult.AsyncState;

            Console.WriteLine(DateTime.Now + ": Empfange Nachricht");

            try
            {
                var responseByteCount = dataPacket.Socket.EndReceive(asyncResult);

                var chars = new char[responseByteCount];

                var decoder = Encoding.UTF8.GetDecoder();
                decoder.GetChars(dataPacket.DataBuffer, 0, responseByteCount, chars, 0);

                if(chars.Count(f => f.Equals(';')) >= 4)
                {
                    var message = new string(chars);

                    dataPacket.GetData(message);
                }

                switch(dataPacket.DataIdentifier) { 
                    case DataIdentifier.Login:
                        try
                        {
                            Console.WriteLine(DateTime.Now + ": Login von " + dataPacket.ClientName);
                            Monitor.Enter(_Lock);

                            var endPoint = dataPacket.Socket.RemoteEndPoint;

                            var endPointCollection = clientList.Select(s => s.Key.RemoteEndPoint).ToList();

                            var istEnthalten = endPointCollection.Contains(endPoint);
                            if(istEnthalten)
                            {
                                clientList[dataPacket.Socket] = dataPacket.SenderPersonOid;
                            }

                            var notificationPacket = new Packet(dataPacket.Socket, dataPacket.ClientName, dataPacket.SenderPersonOid, 0) {DataIdentifier = DataIdentifier.StatusNotificationLogin, Tenant = dataPacket.Tenant};

                            Console.WriteLine(DateTime.Now + ": Benachrichtige die anderen angemeldeten Clients");
                            foreach (var client in clientList.Where(w => !w.Value.Equals(dataPacket.SenderPersonOid)))
                            {
                                client.Key.Send(notificationPacket.GetDataStream());
                            }

                            // Boradcast
                            var abc = clientList.Where(w => w.Value != dataPacket.SenderPersonOid && w.Value > 0).Select(s => s.Value).Distinct().ToList();
                            var msg = "";

                            foreach(var oid in abc)
                            {
                                msg += oid;

                                if(abc.IndexOf(oid) != abc.Count - 1)
                                {
                                    msg += ",";
                                }
                            }

                            if(msg.Length > 0)
                            {
                                var packet = new Packet {ChatMessage = msg, ClientName = dataPacket.ClientName, DataIdentifier = DataIdentifier.StatusNotificationLoginBroadcast, MessageTimeStamp = DateTime.Now, Tenant = dataPacket.Tenant, SenderPersonOid = dataPacket.SenderPersonOid};

                                dataPacket.Socket.Send(packet.GetDataStream());
                            }
                        }
                        finally
                        {
                            Monitor.Exit(_Lock);
                        }

                        break;
                    case DataIdentifier.Message:
                        if(responseByteCount == 0)
                        {
                            try
                            {
                                Console.WriteLine(DateTime.Now + ": Chat-Nachricht ist leer und sorgt dafür, dass der Client ausgeloggt wird");

                                Monitor.Enter(_Lock);

                                var notificationPacketLogout2 = new Packet(dataPacket.Socket, dataPacket.ClientName, dataPacket.SenderPersonOid, 0) {DataIdentifier = DataIdentifier.StatusNotificationLogout};

                                clientList.Remove(dataPacket.Socket);

                                Console.WriteLine(DateTime.Now + ": Leite Logout an die anderen Clients weiter");
                                foreach(var client in clientList)
                                {
                                    client.Key.Send(notificationPacketLogout2.GetDataStream());
                                }

                                dataPacket.Socket.Close();
                            }
                            finally
                            {
                                Monitor.Exit(_Lock);
                            }

                            return;
                        }
                        else
                        {
                            try
                            {
                                Console.BackgroundColor = ConsoleColor.Black;
                                Console.ForegroundColor = ConsoleColor.Red;
                                Console.WriteLine(DateTime.Now + ": Chat-Nachricht erhalten");
                                Console.BackgroundColor = ConsoleColor.Black;
                                Console.ForegroundColor = ConsoleColor.Gray;

                                Monitor.Enter(_Lock);

                                DefaultHibernateSessionManager.CurrentTenant = dataPacket.Tenant;
                                
                                var chatMessage = new ChatMessage
                                {
                                    SenderPersonOid = dataPacket.SenderPersonOid,
                                    ChatText = dataPacket.ChatMessage,
                                    EmpfängerPersonOid = dataPacket.RecipientPersonOid,
                                    Uhrzeit = dataPacket.MessageTimeStamp,
                                    InsUser = dataPacket.ClientName
                                };

                                Console.WriteLine(DateTime.Now + ": Speichere die Chat-Nachricht in die Datenbank");
                                DAOFactory.GenericDAO.Insert(chatMessage);

                                // Testweise die Id einfügen
                                if(chatMessage.Oid != null)
                                {
                                    Console.WriteLine(DateTime.Now + ": Chat-Nachricht erfolgreich mit Oid " + chatMessage.Oid.Value + " gespeichert");
                                    dataPacket.ServerseitigeOid = chatMessage.Oid.Value;
                                }

                                if(dataPacket.RecipientPersonOid > 0)
                                {
                                    if (clientList.ContainsValue(dataPacket.RecipientPersonOid))
                                    {
                                        var recipients = clientList.Where(w => w.Value.Equals(dataPacket.RecipientPersonOid));

                                        Console.WriteLine(DateTime.Now + ": Leite die Chat-Nachricht an die Empfänger (Derselbe User angemeldet an verschiedenen Clients) weiter");
                                        foreach(var recipient in recipients)
                                        {
                                            recipient.Key.Send(dataPacket.GetDataStream());
                                        }
                                    }

                                    var packet = new Packet
                                    {
                                        ClientseitigeOid = dataPacket.ClientseitigeOid, 
                                        ServerseitigeOid = dataPacket.ServerseitigeOid, 
                                        DataIdentifier = DataIdentifier.MessageResponse
                                    };

                                    Console.WriteLine(DateTime.Now + ": Sende Datenbank-Insert-Bestätigung an den Absender, damit die Nachricht später nicht doppelt auf den Client heruntergeladen wird");
                                    dataPacket.Socket.Send(packet.GetDataStream());
                                }
                            }
                            finally
                            {
                                Monitor.Exit(_Lock);
                            }
                        }

                        break;
                    case DataIdentifier.Logout:

                        clientList.Remove(dataPacket.Socket);

                        var notificationPacketLogout = new Packet(dataPacket.Socket, dataPacket.ClientName, dataPacket.SenderPersonOid, 0) {DataIdentifier = DataIdentifier.StatusNotificationLogout};

                        Console.WriteLine(DateTime.Now + ": Sende Logout an alle anderen Clients");
                        foreach (var client in clientList.Where(w => !w.Value.Equals(dataPacket.SenderPersonOid)))
                        {
                            client.Key.Send(notificationPacketLogout.GetDataStream());
                        }

                        break;

                    case DataIdentifier.Team:
                        try
                        {
                            Console.WriteLine(DateTime.Now + ": Team-Nachricht erhalten");

                            Monitor.Enter(_Lock);

                            DefaultHibernateSessionManager.CurrentTenant = dataPacket.Tenant;

                            var chatMessage = new ChatMessage
                            {
                                SenderPersonOid = dataPacket.SenderPersonOid,
                                ChatText = dataPacket.ChatMessage,
                                EmpfängerPersonOid = dataPacket.RecipientPersonOid,
                                Uhrzeit = dataPacket.MessageTimeStamp,
                                InsUser = dataPacket.ClientName,
                                TeamOid = dataPacket.RecipientPersonOid
                            };

                            var team = DAOFactory.GenericDAO.LoadByID<Team>(dataPacket.RecipientPersonOid);

                            Console.WriteLine(DateTime.Now + ": Speichere Team-Nachricht in der Datenbank");
                            DAOFactory.GenericDAO.Insert(chatMessage);

                            var personOids = team.MemberList.Select(s => s.Person.Oid.Value);

                            if (chatMessage.Oid != null)
                            {
                                Console.WriteLine(DateTime.Now + ": Team-Nachricht erfolgreich mit Oid " + chatMessage.Oid.Value + " gespeichert");
                                dataPacket.ServerseitigeOid = chatMessage.Oid.Value;
                            }

                            Console.WriteLine(DateTime.Now + ": Leite die Team-Nachricht an die Empfänger weiter");
                            foreach(var recipient in clientList.Where(w => w.Value != dataPacket.SenderPersonOid && personOids.Contains(w.Value)))
                            {
                                recipient.Key.Send(dataPacket.GetDataStream());
                            }

                            var packet = new Packet
                            {
                                ClientseitigeOid = dataPacket.ClientseitigeOid,
                                ServerseitigeOid = dataPacket.ServerseitigeOid,
                                DataIdentifier = DataIdentifier.MessageResponse
                            };

                            Console.WriteLine(DateTime.Now + ": Sende Datenbank-Insert-Bestätigung an den Absender, damit die Nachricht später nicht doppelt auf den Client heruntergeladen wird");
                            dataPacket.Socket.Send(packet.GetDataStream());
                        }
                        finally
                        {
                            Monitor.Exit(_Lock);
                        }

                        break;

                    case DataIdentifier.StatusNotificationBeschäftigt:

                        SendNotificationPacket(dataPacket, DataIdentifier.StatusNotificationBeschäftigt);

                        break;

                    case DataIdentifier.StatusNotificationOnline:

                        SendNotificationPacket(dataPacket, DataIdentifier.StatusNotificationOnline);

                        break;

                    case DataIdentifier.StatusNotificationOffline:

                        SendNotificationPacket(dataPacket, DataIdentifier.StatusNotificationOffline);

                        break;
                }

                WaitForClientData(dataPacket.Socket, dataPacket.ClientName, dataPacket.SenderPersonOid, dataPacket.RecipientPersonOid);
            }
            catch (Exception e)
            {
                Console.WriteLine(DateTime.Now + ": Ein Fehler ist aufgetreten oder die App ist abgestürzt. Der Client wird ausgeloggt");

                var sender = dataPacket.Socket;

                var notificationPacketLogout = new Packet(dataPacket.Socket, dataPacket.ClientName, dataPacket.SenderPersonOid, 0) { DataIdentifier = DataIdentifier.StatusNotificationLogout };

                try
                {
                    Monitor.Enter(_Lock);

                    if(clientList.ContainsKey(sender))
                    {
                        clientList.Remove(sender);

                        Console.WriteLine(DateTime.Now + ": Leite Logout an die anderen Clients weiter");
                        foreach(var client in clientList)
                        {
                            client.Key.Send(notificationPacketLogout.GetDataStream());
                        }

                        sender.Close();
                    }
                }
                finally
                {
                    Monitor.Exit(_Lock);
                }

                WriteErrorMessageToConsole(e.Message, e.StackTrace);
            }
        }

        private static void SendNotificationPacket(Packet dataPacket, DataIdentifier dataIdentifier)
        {
            var notificationPacket = new Packet(dataPacket.Socket, dataPacket.ClientName, dataPacket.SenderPersonOid, 0) { DataIdentifier = DataIdentifier.StatusNotificationLogout };

            Console.WriteLine(DateTime.Now + ": Sende Statusänderung(" + dataIdentifier + ") an alle anderen Clients");
            foreach (var client in clientList.Where(w => w.Value != dataPacket.SenderPersonOid))
            {
                client.Key.Send(notificationPacket.GetDataStream());
            }
        }

        private static void WriteErrorMessageToConsole(string message, string stackTrace)
        {
            Console.BackgroundColor = ConsoleColor.Black;
            Console.ForegroundColor = ConsoleColor.Red;
            Console.WriteLine(DateTime.Now + ": " + message);
            Console.WriteLine(stackTrace);
            Console.BackgroundColor = ConsoleColor.Black;
            Console.ForegroundColor = ConsoleColor.Gray;
        }
    }
}