[chore:] added messagebox

MessageBox.axaml

@@ -0,0 +1,18 @@
+<Window xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+        mc:Ignorable="d" SizeToContent="WidthAndHeight"
+        x:Class="Logof_Client.MessageBox"
+        Title="MessageBox">
+    <StackPanel>
+        <TextBlock Name="Text" Margin="10" TextWrapping="Wrap" />
+        <StackPanel HorizontalAlignment="Right" Margin="5" Orientation="Horizontal" Name="Buttons">
+            <StackPanel.Styles>
+                <Style Selector="Button">
+                    <Setter Property="Margin" Value="5" />
+                </Style>
+            </StackPanel.Styles>
+        </StackPanel>
+    </StackPanel>
+</Window>

MessageBox.axaml.cs

@@ -0,0 +1,85 @@
+using System;
+using System.Threading.Tasks;
+using Avalonia.Controls;
+using Avalonia.Markup.Xaml;
+
+namespace Logof_Client;
+
+public class MessageBox : Window
+{
+    public MessageBox()
+    {
+        AvaloniaXamlLoader.Load(this);
+    }
+
+    public static Task<MessageBoxResult> Show(Window parent, string text, string title,
+        MessageBoxButton buttons = MessageBoxButton.Ok)
+    {
+        try
+        {
+            var msgbox = new MessageBox
+            {
+                Title = title
+            };
+            msgbox.FindControl<TextBlock>("Text").Text = text;
+            var buttonPanel = msgbox.FindControl<StackPanel>("Buttons");
+
+            var res = MessageBoxResult.Ok;
+
+            void AddButton(string caption, MessageBoxResult r, bool def = false)
+            {
+                var btn = new Button { Content = caption };
+                btn.Click += (_, __) =>
+                {
+                    res = r;
+                    msgbox.Close();
+                };
+                buttonPanel.Children.Add(btn);
+                if (def)
+                    res = r;
+            }
+
+            if (buttons == MessageBoxButton.Ok || buttons == MessageBoxButton.OkCancel)
+                AddButton("Ok", MessageBoxResult.Ok, true);
+            if (buttons == MessageBoxButton.YesNo || buttons == MessageBoxButton.YesNoCancel)
+            {
+                AddButton("Yes", MessageBoxResult.Yes);
+                AddButton("No", MessageBoxResult.No, true);
+            }
+
+            if (buttons == MessageBoxButton.OkCancel || buttons == MessageBoxButton.YesNoCancel)
+                AddButton("Cancel", MessageBoxResult.Cancel, true);
+
+
+            var tcs = new TaskCompletionSource<MessageBoxResult>();
+            msgbox.Closed += delegate { tcs.TrySetResult(res); };
+            if (parent != null)
+                msgbox.ShowDialog(parent);
+            else msgbox.Show();
+
+            return tcs.Task;
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine("Error while showing messagebox: " + ex.Message);
+            return Task.FromResult(MessageBoxResult.Error);
+        }
+    }
+}
+
+public enum MessageBoxButton
+{
+    Ok,
+    OkCancel,
+    YesNo,
+    YesNoCancel
+}
+
+public enum MessageBoxResult
+{
+    Ok,
+    Cancel,
+    Yes,
+    No,
+    Error
+}