Chat/ChatController/ChatMainControl.xaml.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Forms;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Navigation;
using System.Windows.Threading;

using ChatController.ChatKlassen;
using ChatController.Extensions;
using ChatController.HauptKlassen;
using ChatController.LoginKlassen;
using ChatController.Utilities;
using ChatController.Utilities.Extensions;

using Button = System.Windows.Controls.Button;
using Cursors = System.Windows.Input.Cursors;
using DataFormats = System.Windows.DataFormats;
using KeyEventArgs = System.Windows.Input.KeyEventArgs;
using MenuItem = System.Windows.Controls.MenuItem;
using MessageBox = System.Windows.MessageBox;
using Orientation = System.Windows.Controls.Orientation;
using Panel = System.Windows.Controls.Panel;
using Path = System.IO.Path;
using ScrollBar = System.Windows.Controls.Primitives.ScrollBar;
using Timer = System.Windows.Forms.Timer;

namespace ChatController
{
    public partial class ChatMainControl
    {
        private readonly Dictionary<long, List<NotifyIcon>> _Group2NotifyIcons = new Dictionary<long, List<NotifyIcon>>();

        private readonly Dictionary<int, SyncFileInfoStruct> _GroupId2DateTime = new Dictionary<int, SyncFileInfoStruct>();

        private Window _ContainingWindow;

        public Window ContainingWindow
        {
            get => _ContainingWindow;

            set
            {
                _ContainingWindow = value;
                if(value != null)
                {
                    _ContainingWindow.Deactivated += ContainingWindowOnDeactivated;
                    _ContainingWindow.Activated += ContainingWindowOnActivated;
                }
            }
        }

        private Chat _Chat;
        private CurrentContact _CurrentContact;

        private bool _IsChatBoxOnFocus;

        private IOrderedEnumerable<Contact> _ContactList;
        
        private bool _ScrollPrueferAktivieren;

        public bool ShouldInterruptContactsThread = true;

        private readonly List<string> _CreatedTempFiles = new List<string>();

        private readonly Dictionary<string, Action<string>> _MenuItemName2Callback = new Dictionary<string, Action<string>>();

        private bool _IsDesktopVersion = true;

        private bool _IsInBackground;

        public ChatMainControl()
        {
            InitializeComponent();

            ReloadGruppen.Visibility = Visibility.Collapsed;
        }

        private void ContainingWindowOnDeactivated(object sender, EventArgs e)
        {
            _IsInBackground = true;
        }

        private void ContainingWindowOnActivated(object sender, EventArgs e)
        {
            _IsInBackground = false;
        }

        public void InitMitChatdaten(ChatDatenUebergabe cdu)
        {
            _Chat = new Chat(cdu);

            _ContactList = _Chat.AddContacts();

            Clientlist.ItemsSource = _ContactList;

            ReadNewSyncFile();

            foreach (var contact in _ContactList)
            {
                if (_GroupId2DateTime.ContainsKey(contact.GroupId))
                {
                    var dateTimeFromFile = _GroupId2DateTime[contact.GroupId].TimeStamp;
                    var isUnread = _GroupId2DateTime[contact.GroupId].IsUnread;

                    var isYounger = contact.TimeStamp > dateTimeFromFile;

                    contact.IsNewMessage = isUnread;
                    contact.HasUnreadMessages = contact.IsNewMessage;
                }
            }

            var view = (CollectionView) CollectionViewSource.GetDefaultView(Clientlist.ItemsSource);
            view.Filter = UserFilter;

            GlobalListeningThreadtimer?.Stop();
            GlobalListeningThreadtimer = null;
            InitGlobalListeningThread();

            Clientlist.Items.Refresh();
        }

        public void ShowNotification(string pTitle, GroupLatestMessage pMessage, int pGroupId)
        {
            var notificationIcon = Resource.ownchat_favicon;

            var contact = _ContactList.FirstOrDefault(a => a.GroupId == pGroupId);

            if (contact != null)
            {
                notificationIcon = Utils.ImageSourceToIcon(contact.Image);
            }

            var notifyIcon = new NotifyIcon { Icon = notificationIcon, Visible = true, Tag = pMessage };

            notifyIcon.BalloonTipClicked += (sender, args) =>
            {
                DisposeAndRemoveNotification((NotifyIcon)sender, pGroupId);

                if (_ContainingWindow.WindowState == WindowState.Minimized)
                {
                    _ContainingWindow.WindowState = WindowState.Normal;
                }

                _ContainingWindow.Activate();

                SelectContact(_ContactList.FirstOrDefault(f => f.GroupId.Equals(pGroupId)));
            };

            notifyIcon.BalloonTipClosed += (sender, args) =>
            {
                DisposeAndRemoveNotification((NotifyIcon)sender, pGroupId);
            };

            _Group2NotifyIcons.AddOrUpdateValueInDictionary(pGroupId, notifyIcon);

            _Group2NotifyIcons[pGroupId].Find(f => f.Tag is GroupLatestMessage message && message.Id.Equals(pMessage.Id))?.ShowBalloonTip(Constants.NotificationTimeout, pTitle, "Sie haben eine neue Nachricht", ToolTipIcon.None);
        }

        public void ClearNotifications()
        {
            foreach(var group2NotifyIcon in _Group2NotifyIcons)
            {
                foreach(var notifyIcon in group2NotifyIcon.Value)
                {
                    notifyIcon.Dispose();
                }
            }

            _Group2NotifyIcons.Clear();
        }

        private void DisposeAndRemoveNotification(IDisposable pNotification, long pGroupId)
        {
            pNotification.Dispose();
            _Group2NotifyIcons.Remove(pGroupId);
        }

        public void ResetStyle()
        {
            EmojiButton.Style = null;
            MediaButton.Style = null;
            ReloadGruppen.Visibility = Visibility.Visible;
            _IsDesktopVersion = false;
        }
        
        private void AktChatUser_OnMouseDoubleClick(object sender, MouseButtonEventArgs e)
        {
            _Chat.ShowProfilePicture(_CurrentContact);
        }

        private void Clientlist_OnSelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if(Clientlist.SelectedItem != null)
            {
                SelectContact((Contact) Clientlist.SelectedItem);
            }
        }

        private void SelectContact(Contact pContact)
        {
            if(pContact == null)
            {
                return;
            }

            ShouldInterruptContactsThread = true;

            Cursor = Cursors.Wait;
            _ScrollPrueferAktivieren = false;

            AktChatUserList.Items.Clear();

            if (pContact.HasUnreadMessages)
            {
                pContact.HasUnreadMessages = false;

                Clientlist.Items.Refresh();
            }

            var currentContact = new CurrentContact(pContact);
            pContact.IsNewMessage = false;

            var shouldChangeIcon = _ContactList.Any(contact => contact.IsNewMessage);
            if(shouldChangeIcon)
            {
                ContainingWindow.Icon = Utils.GetImageSourceFromIcon(Resource.ownchat_favicon);
            }

            AktChatUserList.Items.Add(currentContact);
            _CurrentContact = currentContact;

            if(Clientlist.Items.Contains(pContact))
            {
                Clientlist.SelectedItem = pContact;
            }

            var chatMessages = _Chat.LoadChatMessagesForContact(currentContact);
            
            ChatListBox.ItemsSource = chatMessages;

            if (VisualTreeHelper.GetChildrenCount(ChatListBox) > 0)
            {
                var border = (Border) VisualTreeHelper.GetChild(ChatListBox, 0);
                var scrollViewer = (ScrollViewer) VisualTreeHelper.GetChild(border, 0);
                scrollViewer.ScrollToBottom();
            }

            ChatListBox.ContextMenu = _Chat.ErstelleKontextMenue();
            SetContextHandler();
            _ScrollPrueferAktivieren = true;

            ListenForMessages();
            Cursor = Cursors.Arrow;

            WriteToNewSyncFile();

            ShouldInterruptContactsThread = false;
        }

        private void SetContextHandler()
        {
            var contextItems = ChatListBox?.ContextMenu?.Items;

            foreach (var menuItemText in _MenuItemName2Callback.Keys)
            {
                var cb = _MenuItemName2Callback[menuItemText];

                var menuItem = new MenuItem();

                menuItem.Click += (s, e2) =>
                {
                    cb(menuItemText);
                };
                menuItem.Header = menuItemText;

                contextItems.Add(menuItem);
            }

            var item2 = (MenuItem)contextItems[0];
            item2.Click += Item2OnClick; // umbenenen in Speichern unter 
            var item3 = (MenuItem)contextItems[1];
            item3.Click += Item3OnClick; //Umbenenen in Einfügen 

            // neu und vor Einfügen setzen und anpassen
            var item4 = (MenuItem) contextItems[2];
            item4.Click += Item4OnClick; //Umbenenen in Kopieren
            
        }

        private void Item2OnClick(object sender, RoutedEventArgs routedEventArgs)
        {
            foreach (var items in ChatListBox.SelectedItems)
            {
                var item = (ChatMessage)items;

                _Chat.SaveFileAs(item);
            }
        }

        private void Item3OnClick(object sender, RoutedEventArgs routedEventArgs)
        {
            var kontakt = (CurrentContact)AktChatUserList.Items[0];
            _Chat.Paste(kontakt.GroupId,this);          
        }

        private void Item4OnClick(object sender, RoutedEventArgs routedEventArgs)
        { 
            string chatmessages = "";
            foreach (var items in ChatListBox.SelectedItems)
            {
                var item = (ChatMessage)items;

                chatmessages += item.UserMessage + "\n";
            }

            if(!chatmessages.Equals(""))
                _Chat.Copy(chatmessages, 1);
        }

        private void Chat_OnContextMenuOpening(object sender, ContextMenuEventArgs e)
        {
            var chatItems = ChatListBox.SelectedItems;

            if (chatItems.Count > 0)
            {
                foreach (var items in chatItems)
                {
                    var item = items as ChatMessage;
                    if (item != null && item.ImageSources != null)
                    {
                        var contextItems = ChatListBox.ContextMenu.Items;
                        var ContextItemSpeichernUnter = (MenuItem)contextItems[0];
                        ContextItemSpeichernUnter.Visibility = Visibility.Visible;
                    }
                    else
                    {
                        var contextItems = ChatListBox.ContextMenu.Items;
                        var ContextItemSpeichernUnter = (MenuItem)contextItems[0];
                        ContextItemSpeichernUnter.Visibility = Visibility.Collapsed;
                    }

                    if (item.ImageSources == null && item.FilePath == null)
                    {
                        var contextItems = ChatListBox.ContextMenu.Items;
                        var ContextItemSpeichernUnter = (MenuItem) contextItems[2];
                        ContextItemSpeichernUnter.Visibility = Visibility.Visible;
                    }
                    else
                    {
                        var contextItems = ChatListBox.ContextMenu.Items;
                        var ContextItemSpeichernUnter = (MenuItem)contextItems[2];
                        ContextItemSpeichernUnter.Visibility = Visibility.Collapsed;
                    }


                }
            }
            else
            {
                //Schalte speichern unter Aus 
                var contextItems = ChatListBox.ContextMenu.Items;
                var ContextItemSpeichernUnter = (MenuItem)contextItems[0];
                ContextItemSpeichernUnter.Visibility = Visibility.Collapsed;
            }


            //prüfe ob was in dem Speicher vorhanden ist //Einfügen
            var d = System.Windows.Forms.Clipboard.GetDataObject();

            if (d.GetDataPresent(DataFormats.FileDrop))
            {
                var contextItems = ChatListBox.ContextMenu.Items;
                var ContextItemSpeichernUnter = (MenuItem)contextItems[1];
                ContextItemSpeichernUnter.Visibility = Visibility.Visible;
            }
            else if (d.GetDataPresent(DataFormats.Text))
            {
                var contextItems = ChatListBox.ContextMenu.Items;
                var ContextItemSpeichernUnter = (MenuItem)contextItems[1];
                ContextItemSpeichernUnter.Visibility = Visibility.Visible;
            }
            else if (d.GetDataPresent(DataFormats.Bitmap))
            {
                var contextItems = ChatListBox.ContextMenu.Items;
                var ContextItemSpeichernUnter = (MenuItem)contextItems[1];
                ContextItemSpeichernUnter.Visibility = Visibility.Visible;
            }
            else
            {
                var contextItems = ChatListBox.ContextMenu.Items;
                var ContextItemSpeichernUnter = (MenuItem)contextItems[1];
                ContextItemSpeichernUnter.Visibility = Visibility.Collapsed;
            }

            //prüfe ob dokumentation erlaubt
            var kontakt = (CurrentContact)AktChatUserList.Items[0];
            if (kontakt.UserIdManage == null && ChatListBox.ContextMenu.Items.Count > 3)
            {
                var contextItems = ChatListBox.ContextMenu.Items;
                var ContextItemSpeichernUnter = (MenuItem)contextItems[3];
                ContextItemSpeichernUnter.Visibility = Visibility.Collapsed;
            }
            else if (ChatListBox.ContextMenu.Items.Count > 3)
            {
                var contextItems = ChatListBox.ContextMenu.Items;
                var ContextItemSpeichernUnter = (MenuItem)contextItems[3];
                ContextItemSpeichernUnter.Visibility = Visibility.Visible;
            }
            


            if (ChatListBox.ContextMenu.Items.Count == 0)
            {
                ChatListBox.ContextMenu.Visibility = Visibility.Collapsed;
            }

        }

        private void MediaButton_OnClick(object sender, RoutedEventArgs e)
        {
            if (AktChatUserList.Items.Count > 0)
            {
                var kontakt = (CurrentContact)AktChatUserList.Items[0];
                
                var medium = _Chat.OpenFile();

                if(medium != null) {

                    string convertetMedia = _Chat.ScaleImage(medium, Path.GetExtension(medium.ToUpperInvariant()));

                    if (!convertetMedia.Equals(""))
                    {
                        _Chat.AddNewFile(convertetMedia,medium,kontakt.GroupId);

                        CollectionViewSource.GetDefaultView(ChatListBox.ItemsSource).Refresh();
                        ChatListBox.Items.MoveCurrentToLast();
                        ChatListBox.ScrollIntoView(ChatListBox.Items.CurrentItem);

                        _Chat.SendFileToContact(kontakt, convertetMedia,medium);

                        if (!convertetMedia.Equals("") && !convertetMedia.Equals(medium) && File.Exists(convertetMedia))
                        {
                            File.Delete(convertetMedia);
                        }
                    }
                    else
                    {
                        MessageBox.Show("Die gewählte Datei ist zu groß!", "Fehler", MessageBoxButton.OK, MessageBoxImage.Exclamation);
                    }
                }
            }
            else
            {
                MessageBox.Show("Bitte wählen Sie einen Kontakt aus.","ownChat",MessageBoxButton.OK, MessageBoxImage.Information);
            }
        }

        private void SendButton_OnClick(object sender, RoutedEventArgs e)
        {
            if (!AktChatUserList.Items.IsEmpty && !Chatbox.Text.Equals("") && _IsChatBoxOnFocus)
            {
                if (!Chatbox.Text.Equals(""))
                {
                    var kontakt = (CurrentContact)AktChatUserList.Items[0];
                     
                    _Chat.AddNewMessage(Chatbox.Text, kontakt.GroupId);
                    
                    CollectionViewSource.GetDefaultView(ChatListBox.ItemsSource).Refresh();

                    ChatListBox.Items.MoveCurrentToLast();
                    ChatListBox.ScrollIntoView(ChatListBox.Items.CurrentItem);
                    
                    _Chat.SendMessage(Chatbox.Text, kontakt.GroupId);

                    Chatbox.Text = "";
                    
                    if (Chatbox.Text.Equals(""))
                    {
                        Chatbox.Text = "Nachricht schreiben";
                        Chatbox.Foreground = new SolidColorBrush(Colors.DarkGray);
                        _IsChatBoxOnFocus = false;
                    }
                }
            }
            else
            {
                if (AktChatUserList.Items.IsEmpty)
                {
                    MessageBox.Show("Bitte wählen Sie einen Chatpartner aus.", "Fehler", MessageBoxButton.OK);
                    if (string.IsNullOrEmpty(Chatbox.Text))
                    {
                        Chatbox.Text = "Nachricht schreiben";
                        Chatbox.Foreground = new SolidColorBrush(Colors.DarkGray);
                        _IsChatBoxOnFocus = false;
                    }
                }
                else if (string.IsNullOrEmpty(Chatbox.Text))
                {
                    MessageBox.Show("Sie können keine leere Nachricht verschicken.", "Fehler", MessageBoxButton.OK);
                    
                    Chatbox.Text = "Nachricht schreiben";
                    Chatbox.Foreground = new SolidColorBrush(Colors.DarkGray);
                    _IsChatBoxOnFocus = false;
                }
            }
        }

        private void Chatbox_OnGotFocus(object sender, RoutedEventArgs e)
        {
            if (Chatbox.Text.Equals("Nachricht schreiben"))
            {
                Chatbox.Text = "";
                Chatbox.Foreground = new SolidColorBrush(Colors.Black);
                _IsChatBoxOnFocus = true;
            }
        }

        private void Chatbox_OnKeyDownHandler(object sender, KeyEventArgs e)
        {
            try
            {
                if (e.Key == Key.Return)
                {
                    if (!AktChatUserList.Items.IsEmpty && !Chatbox.Text.Equals(""))
                    {
                        var kontakt = (CurrentContact)AktChatUserList.Items[0];
 
                        _Chat.AddNewMessage(Chatbox.Text, kontakt.GroupId);
                        
                        CollectionViewSource.GetDefaultView(ChatListBox.ItemsSource).Refresh();
                        ChatListBox.Items.MoveCurrentToLast();
                        ChatListBox.ScrollIntoView(ChatListBox.Items.CurrentItem);
                       
                        _Chat.SendMessage(Chatbox.Text, kontakt.GroupId);

              
                        Chatbox.Text = "";
                        
                    }
                    else
                    {
                        if (AktChatUserList.Items.IsEmpty)
                        {
                            MessageBox.Show("Bitte wählen Sie einen Chatpartner aus.", "Fehler", MessageBoxButton.OK);
                        }
                        else if (Chatbox.Text.Equals(""))
                        {
                            MessageBox.Show("Sie können keine leere Nachricht verschicken.", "Fehler", MessageBoxButton.OK);
                        }
                    }
                }
            }
            catch (Exception ed)
            {
                MessageBox.Show("Beim Senden einer Nachricht ist ein Fehler aufgetreten. " + ed.Message + "\n" + ed.StackTrace, "Fehler", MessageBoxButton.OK);
            }
        }

        public delegate void EmojiiDelegate(Button button);

        public event EmojiiDelegate OnEmojii;

        private void EmojiButton_OnClick(object sender, RoutedEventArgs e)
        {          
                //hier wie bei login 
                if (OnEmojii != null)
                {
                    OnEmojii(EmojiButton);
                }             
        }
        
        private void Chat_OnScrollChanged(object sender, ScrollChangedEventArgs e)
        {
            var scrollBarList = GetVisualChildCollection<ScrollBar>(ChatListBox);
            foreach (var scrollBar in scrollBarList)
            {
                if (scrollBar.Orientation == Orientation.Horizontal)
                {
                    _ScrollPrueferAktivieren = true;
                }
                else
                {
                    scrollBar.ValueChanged += VerticalScrollbarChanged;
                }
            }
        }

        private void VerticalScrollbarChanged(object sender, RoutedPropertyChangedEventArgs<double> routedPropertyChangedEventArgs)
        {
            if (_ScrollPrueferAktivieren == true)
            {
                var x = (ScrollBar) sender;

                if (x.Value > 0)
                {
                    //nix
                }
                else
                {
                    Cursor = Cursors.Wait;
                    //StartWaiting();               
                    _ScrollPrueferAktivieren = false;

                    ChatListBox.Items.MoveCurrentToFirst();
                    ChatMessage item = ChatListBox.Items.CurrentItem as ChatMessage;

                    ChatListBox.ItemsSource = null;

                    var kontakt = (Contact)Clientlist.SelectedItem;

                    var xy = _Chat.LoadMoreMessages(kontakt);

                    ChatListBox.ItemsSource = xy;

                    ChatListBox.ScrollIntoView(item);      
                    //EndWaiting();
                    Cursor = Cursors.Arrow;
                }           
            }         
        }

        private static List<T> GetVisualChildCollection<T>(object parent) where T : Visual
        {
            var visualCollection = new List<T>();
            GetVisualChildCollection(parent as DependencyObject, visualCollection);

            return visualCollection;
        }

        private static void GetVisualChildCollection<T>(DependencyObject parent, ICollection<T> visualCollection) where T : Visual
        {
            var count = VisualTreeHelper.GetChildrenCount(parent);
            for (var i = 0; i < count; i++)
            {
                var child = VisualTreeHelper.GetChild(parent, i);

                if (child is T item)
                {
                    visualCollection.Add(item);
                }
                else
                {
                    GetVisualChildCollection(child, visualCollection);
                }
            }
        }

        private void ListenForMessages()
        {
            _ListeningThreadTimer?.Stop();
            _ListeningThreadTimer = null;
            InitListeningThread((CurrentContact)AktChatUserList.Items[0]);
        }

        public Timer _ListeningThreadTimer;
        public Timer GlobalListeningThreadtimer { get; set; }

        private void InitGlobalListeningThread()
        {
            GlobalListeningThreadtimer = new Timer();
            GlobalListeningThreadtimer.Tick += GlobalListeningThreadTimerTickEvent;
            GlobalListeningThreadtimer.Interval = 2000;
            GlobalListeningThreadtimer.Start();
        }

        private void GlobalListeningThreadTimerTickEvent(object sender, EventArgs e)
        {
            ListenGloballyForMessages();
        }

        private void ListenGloballyForMessages()
        {
            var numberOfNewMessages = _Chat.GetNumberOfAllNewMessages();

            if (numberOfNewMessages > 0)
            {
                Dispatcher.BeginInvoke(
                DispatcherPriority.Normal,
                (Action)delegate
                {
                    var contacts = _Chat.NeueGroupklassenKontakte().ToList();

                    CurrentContact currentContact = null;

                    if (AktChatUserList.HasItems)
                    {
                        currentContact = (CurrentContact)AktChatUserList.Items[0];
                    }

                    foreach (var contact in _ContactList)
                    {
                        foreach (var newContact in contacts)
                        {
                            if (contact.GroupId == newContact.GroupId)
                            {
                                // ReceivedMessage kann null sein!
                                if (contact.ReceivedMessage != null && !contact.ReceivedMessage.Id.Equals(newContact.ReceivedMessage?.Id))
                                {
                                    contact.ReceivedMessage = newContact.ReceivedMessage;
                                    contact.TimeStamp = newContact.TimeStamp;

                                    // TODO: Prüfen, ob die App im Hintergrund oder minimiert ist
                                    if ((Clientlist.SelectedItem != null && !((Contact)Clientlist.SelectedItem).GroupId.Equals(newContact.GroupId) || Clientlist.SelectedItem == null) || _IsInBackground)
                                    {
                                        ContainingWindow.Icon = Utils.GetImageSourceFromIcon(Resource.oC_favico_NewMessage);
                                        ShowNotification(newContact.Name, newContact.ReceivedMessage, newContact.GroupId);
                                    }

                                    // Wenn der momentan ausgewählte Kontakt der aktuelle Kontakt in der Schleife ist, werden die Nachrichten nicht als ungelesen angezeigt, sonst schon.
                                    if (currentContact != null && newContact.GroupId == currentContact.GroupId)
                                    {
                                        contact.HasUnreadMessages = false;
                                    }
                                    else
                                    {
                                        contact.HasUnreadMessages = true;
                                        contact.IsNewMessage = true;
                                    }
                                }
                            }

                            if (!_ContactList.Contains(newContact))
                            {
                                _ContactList.ToList().Add(newContact);
                            }
                        }

                        if (!contacts.Contains(contact))
                        {
                            _ContactList.ToList().Remove(contact);
                        }
                    }

                    Clientlist.Items.Refresh();
                });
            }
        }

        private void InitListeningThread(CurrentContact pCurrentContacObject)
        {
            _ListeningThreadTimer = new Timer {Tag = pCurrentContacObject};
            _ListeningThreadTimer.Tick += ListeningThreadTimerTickEvent;
            _ListeningThreadTimer.Interval = 2000;
            _ListeningThreadTimer.Start();
        }

        private void ListeningThreadTimerTickEvent(object sender, EventArgs e)
        {
            ListenForMessagesForCurrentContact((CurrentContact) ((Timer) sender).Tag);
        }

        private void ListenForMessagesForCurrentContact(CurrentContact pCurrentContact)
        {
            if (!ShouldInterruptContactsThread)
            {
                var hasNewMessages = _Chat.CheckIfNewMessagesExist(pCurrentContact);

                if (hasNewMessages)
                {
                    Dispatcher.BeginInvoke(DispatcherPriority.Background,
                        (Action)delegate
                        {
                            _Chat.LoadChatMessagesForContact(pCurrentContact);

                            CollectionViewSource.GetDefaultView(ChatListBox.ItemsSource).Refresh();

                            ChatListBox.Items.MoveCurrentToLast();
                            ChatListBox.ScrollIntoView(ChatListBox.Items.CurrentItem);
                        });
                }
            }
        }

        private void Suche_OnTextChanged(object sender, TextChangedEventArgs e)
        {
            CollectionViewSource.GetDefaultView(Clientlist.ItemsSource).Refresh();
        }

        private bool UserFilter(object item)
        {
            if (String.IsNullOrEmpty(Suche.Text))
                return true;
            else
                return ((item as Contact).Name.IndexOf(Suche.Text, StringComparison.OrdinalIgnoreCase) >= 0);
        }

        private void Chat_OnMouseDoubleClick(object sender, MouseButtonEventArgs e)
        {
            Cursor = Cursors.Wait;
            
            var chatItems = ChatListBox.SelectedItems;

            if (chatItems.Count > 0)
            {
                foreach (var items in chatItems)
                {
                    var item = items as ChatMessage;

                    if (item != null && item.ImageSources != null)
                    {                       
                        StartWaiting();
                        _Chat.ShowPicture(item, EndWaiting);                                             
                    }
                    else if(item != null && item.FilePath != null)
                    {
                        var filename = Path.GetFileName(item.FilePath.ToString());
                        LoadDocument(item.FilePath.ToString(), filename);
                    }                   
                }

                Cursor = Cursors.Arrow;
            }
            else
            {
                Cursor = Cursors.Arrow;
            }        
        }

        private void LoadDocument(string link, string filename)
        {
            try
            {
                StartWaiting();

                var path = Path.Combine(Path.GetTempPath(), filename);
                _CreatedTempFiles.Add(path);
                if (!File.Exists(path))
                {
                    using (var webClient = new WebClient())
                    {
                        webClient.DownloadFile(link, path);
                    }

                    if (File.Exists(path))
                    {
                        Process.Start(path);
                    }
                }
                else
                {
                    Process.Start(path);
                }
            }
            catch (Exception e)
            {

            }
            finally
            {
                EndWaiting();
            }
        }

        private ChatControlWaitLayer _waitLayer;

        public void StartWaiting()
        {
            Dispatcher.BeginInvoke(DispatcherPriority.Background, (Action)StartWaitingImmediately);
        }

        public void StartWaitingImmediately()
        {
            if (_waitLayer == null)
            {
                _waitLayer = new ChatControlWaitLayer();
                //Grid.SetColumnSpan(_waitLayer, 3);
                Grid.SetRowSpan(_waitLayer, 3);
                GridRechts.Children.Add(_waitLayer);
                Panel.SetZIndex(_waitLayer, int.MaxValue);
                _waitLayer.RefreshChatUI();               
            }
        }

        public void EndWaiting()
        {
            Dispatcher.BeginInvoke(
                DispatcherPriority.Background,
                (Action)delegate
                {
                    if (_waitLayer != null)
                    {
                        GridRechts.Children.Remove(_waitLayer);
                        _waitLayer = null;
                    }
                });
        }

        private void Hyperlink_OnRequestNavigate(object sender, RequestNavigateEventArgs e)
        {
            Process.Start(e.Uri.ToString());
        }

        private void ButtonReloadGruppen_OnClick(object sender, RoutedEventArgs e)
        {        
            DoSynchro();
        }
        
        private void DoSynchro()
        {
            try
            {
                Cursor = Cursors.Wait;

                WriteToNewSyncFile();

                var aktuelleGruppen = _Chat.UpdateGroups();

                _ContactList = _Chat.GroupklassenAktuallisieren(aktuelleGruppen);

                ReadNewSyncFile();
                
                Clientlist.Items.Refresh();
                
                Cursor = Cursors.Arrow;
            }
            catch (Exception e)
            {
                MessageBox.Show("Ein Fehler bei der Synchronisation ist aufgetreten.\nFehler:\n" + e.Message, "Fehler", MessageBoxButton.OK);
            }
        }
        
        // Speichert die TimeStamps der zuletzt empfangenen Nachrichten
        public void WriteToNewSyncFile()
        {
            try
            {
                if (File.Exists(Path.Combine(Utils.GetAndCreateUserAppDataPath(), Resource.SyncFile2Name)))
                {
                    File.SetAttributes(Path.Combine(Utils.GetAndCreateUserAppDataPath(), Resource.SyncFile2Name), FileAttributes.Normal);
                    File.Delete(Path.Combine(Utils.GetAndCreateUserAppDataPath(), Resource.SyncFile2Name));
                }

                using (var streamWriter = new StreamWriter(Path.Combine(Utils.GetAndCreateUserAppDataPath(), Resource.SyncFile2Name)))
                {
                    Encoding enc = new UTF8Encoding();

                    foreach (var contact in _ContactList.ToList().Where(contact => contact.ReceivedMessage != null))
                    {
                        var text = contact.GroupId + ";" + contact.TimeStamp.ToUniversalTime() + ";" + contact.IsNewMessage + ";";
                        var bytes = enc.GetBytes(text);
                        var base64String = Convert.ToBase64String(bytes);

                        streamWriter.WriteLine(base64String);
                    }

                    File.SetAttributes(Path.Combine(Utils.GetAndCreateUserAppDataPath(), Resource.SyncFile2Name), FileAttributes.ReadOnly);
                }
            }
            catch (Exception exception)
            {

            }
        }

        public void ReadNewSyncFile()
        {
            try
            {
                if(File.Exists(Path.Combine(Utils.GetAndCreateUserAppDataPath(), Resource.SyncFile2Name)))
                {
                    using (var streamReader = new StreamReader(Path.Combine(Utils.GetAndCreateUserAppDataPath(), Resource.SyncFile2Name), true))
                    {
                        string line;

                        _GroupId2DateTime.Clear();

                        while ((line = streamReader.ReadLine()) != null)
                        {
                            var encodedTextBytes = Convert.FromBase64String(line);
                            var plainText = Encoding.UTF8.GetString(encodedTextBytes);
                            var splitPlainText = plainText.Split(';');

                            // Ist kein Datum vorhanden -> 01.01.0001 00:00:00

                            var groupId = int.Parse(splitPlainText[0]);
                            var dateTime = DateTime.Parse(splitPlainText[1]);
                            var isUnread = splitPlainText.Length <= 2 || string.IsNullOrEmpty(splitPlainText[2]) || bool.Parse(splitPlainText[2]);

                            _GroupId2DateTime.Add(groupId, new SyncFileInfoStruct(isUnread, dateTime));
                        }
                    }

                    var latestDateTime = Utils.DefaultDate;

                    foreach(var id2dateTime in _GroupId2DateTime)
                    {
                        if(id2dateTime.Value.TimeStamp > latestDateTime)
                        {
                            latestDateTime = id2dateTime.Value.TimeStamp;
                        }
                    }

                    _Chat.LastTimeStamp = latestDateTime.GetUnixTimeStamp();
                }
            }
            catch (Exception e)
            {
                
            }
        }

        public List<Contact> GetContactsWithoutUnreadMessages()
        {
            var contacts = new List<Contact>();

            Clientlist.Items.Refresh();

            foreach(var contactItem in Clientlist.Items)
            {
                if(contactItem is Contact contact && contact.HasUnreadMessages && !string.IsNullOrEmpty(contact.ReceivedMessage?.Text))
                {
                    contacts.Add(contact);
                }
            }

            return contacts;
        }

        public void ResetNumberOfUnreadMessages(Dictionary<long, DateTime> pGroupId2DateTime)
        {
            if(pGroupId2DateTime != null)
            {
                foreach(var contact in _ContactList)
                {
                    foreach(var groupId2DateTime in pGroupId2DateTime)
                    {
                        if(contact.GroupId == groupId2DateTime.Key)
                        {
                            contact.HasUnreadMessages = false;
                        }
                    }
                }
            }
        }

        public List<ChatMessage> GetSelectedMessages()
        {
            var messages = (from object selectedItem in ChatListBox.SelectedItems select selectedItem as ChatMessage).ToList();

            return messages.Count > 0 ? messages : null;
        }

        public CurrentContact GetCurrentContact()
        {
            if(AktChatUserList != null && AktChatUserList.Items.Count > 0)
            {
                var contact = (CurrentContact) AktChatUserList.Items[0];

                return contact.UserIdManage == null ? null : contact;
            }

            return null;
        }

        public void AddContextMenu(string menuItemText, Action<string> callBackAction)
        {
            if (!_MenuItemName2Callback.ContainsKey(menuItemText))
            {
                _MenuItemName2Callback.Add(menuItemText, callBackAction);
            }
        }

        public void DeleteTempFiles()
        {
            foreach (var file in _CreatedTempFiles)
            {
                try
                {
                    if (File.Exists(file))
                    {
                        File.Delete(file);
                    }
                }
                catch (Exception e)
                {
                    //ignore
                }
            }
        }
    }
}