Add Code completion namespaces

StabilityMatrix.Avalonia/Behaviors/TextEditorCompletionBehavior.cs

@@ -0,0 +1,162 @@
+using System;
+using System.Linq;
+using Avalonia;
+using Avalonia.Input;
+using Avalonia.Xaml.Interactivity;
+using AvaloniaEdit;
+using AvaloniaEdit.Document;
+using AvaloniaEdit.Editing;
+using NLog;
+using StabilityMatrix.Avalonia.Controls.CodeCompletion;
+using StabilityMatrix.Avalonia.Models;
+using CompletionWindow = StabilityMatrix.Avalonia.Controls.CodeCompletion.CompletionWindow;
+
+namespace StabilityMatrix.Avalonia.Behaviors;
+
+public class TextEditorCompletionBehavior : Behavior<TextEditor>
+{
+    private static readonly Logger Logger = LogManager.GetCurrentClassLogger();
+    
+    private TextEditor textEditor = null!;
+    
+    private CompletionWindow? completionWindow;
+
+    // ReSharper disable once MemberCanBePrivate.Global
+    public static readonly StyledProperty<string> TextProperty =
+        AvaloniaProperty.Register<TextEditorCompletionBehavior, string>(nameof(Text));
+
+    public string Text
+    {
+        get => GetValue(TextProperty);
+        set => SetValue(TextProperty, value);
+    }
+    
+    protected override void OnAttached()
+    {
+        base.OnAttached();
+
+        if (AssociatedObject is not { } editor)
+        {
+            throw new NullReferenceException("AssociatedObject is null");
+        }
+        
+        textEditor = editor;
+        textEditor.TextArea.TextEntered += TextArea_TextEntered;
+        textEditor.TextArea.TextEntering += TextArea_TextEntering;
+    }
+
+    protected override void OnDetaching()
+    {
+        base.OnDetaching();
+
+        textEditor.TextArea.TextEntered -= TextArea_TextEntered;
+        textEditor.TextArea.TextEntering -= TextArea_TextEntering;
+    }
+
+    private CompletionWindow CreateCompletionWindow(TextArea textArea)
+    {
+        var window = new CompletionWindow(textArea)
+        {
+            WindowManagerAddShadowHint = false,
+            CloseWhenCaretAtBeginning = true,
+            CloseAutomatically = true,
+            IsLightDismissEnabled = true,
+            CompletionList =
+            {
+                IsFiltering = true
+            }
+        };
+        
+        var completionList = window.CompletionList;
+            
+        completionList.CompletionData.Add(new CompletionData("item1"));
+        completionList.CompletionData.Add(new CompletionData("item2"));
+        completionList.CompletionData.Add(new CompletionData("item3"));
+        
+        return window;
+    }
+
+    private void TextArea_TextEntered(object? sender, TextInputEventArgs e)
+    {
+        if (e.Text is not { } triggerText) return;
+        
+        if (triggerText.All(char.IsLetterOrDigit))
+        {
+            // Create completion window if its not already created
+            if (completionWindow == null)
+            {
+                // Get the segment of the token the caret is currently in
+                if (GetCaretToken(textEditor) is not { } tokenSegment)
+                {
+                    Logger.Trace("Token segment not found");
+                    return;
+                }
+
+                var token = textEditor.Document.GetText(tokenSegment);
+                Logger.Trace("Using token {Token} ({@Segment})", token, tokenSegment);
+                
+                completionWindow = CreateCompletionWindow(textEditor.TextArea);
+                completionWindow.StartOffset = tokenSegment.Offset;
+                completionWindow.EndOffset = tokenSegment.EndOffset;
+                
+                completionWindow.CompletionList.SelectItem(token);
+                
+                completionWindow.Closed += delegate
+                {
+                    completionWindow = null;
+                };
+            
+                completionWindow.Show();
+            }
+        }
+    }
+
+    private void TextArea_TextEntering(object? sender, TextInputEventArgs e)
+    {
+        if (completionWindow is null) return;
+        
+        // When completion window is open, parse and update token offsets
+        if (GetCaretToken(textEditor) is not { } tokenSegment)
+        {
+            Logger.Trace("Token segment not found");
+            return;
+        }
+
+        completionWindow.StartOffset = tokenSegment.Offset;
+        completionWindow.EndOffset = tokenSegment.EndOffset;
+
+        /*if (e.Text?.Length > 0) {
+            if (!char.IsLetterOrDigit(e.Text[0])) {
+                // Whenever a non-letter is typed while the completion window is open,
+                // insert the currently selected element.
+                completionWindow?.CompletionList.RequestInsertion(e);
+            }
+        }*/
+        // Do not set e.Handled=true.
+        // We still want to insert the character that was typed.
+    }
+
+    /// <summary>
+    /// Gets a segment of the token the caret is currently in.
+    /// </summary>
+    private static ISegment? GetCaretToken(TextEditor textEditor)
+    {
+        var caret = textEditor.CaretOffset;
+
+        // Search for the start and end of a token
+        // A token is defined as either alphanumeric chars or a space
+        var start = caret;
+        while (start > 0 && char.IsLetterOrDigit(textEditor.Document.GetCharAt(start - 1)))
+        {
+            start--;
+        }
+        
+        var end = caret;
+        while (end < textEditor.Document.TextLength && char.IsLetterOrDigit(textEditor.Document.GetCharAt(end)))
+        {
+            end++;
+        }
+        
+        return start < end ? new TextSegment { StartOffset = start, EndOffset = end } : null;
+    }
+}

StabilityMatrix.Avalonia/Controls/CodeCompletion/CompletionData.cs

@@ -0,0 +1,128 @@
+using System;
+using System.Diagnostics;
+using Avalonia.Controls;
+using Avalonia.Controls.Documents;
+using Avalonia.Media;
+using AvaloniaEdit.Document;
+using AvaloniaEdit.Editing;
+using StabilityMatrix.Avalonia.Models;
+using StabilityMatrix.Avalonia.Styles;
+using StabilityMatrix.Core.Extensions;
+
+namespace StabilityMatrix.Avalonia.Controls.CodeCompletion;
+
+/// <summary>
+/// Provides entries in AvaloniaEdit completion window.
+/// </summary>
+public class CompletionData : ICompletionData
+{
+    /// <inheritdoc />
+    public string Text { get; }
+    
+    /// <inheritdoc />
+    public string? Description { get; init; }
+    
+    /// <inheritdoc />
+    public IImage? Image { get; set; }
+
+    /// <inheritdoc />
+    public IconData? Icon { get; init; } 
+    
+    /// <summary>
+    /// Cached <see cref="TextBlock"/> instance.
+    /// </summary>
+    private object? _content;
+    
+    /// <inheritdoc />
+    public object Content => _content ??= new TextBlock
+    {
+        Inlines = CreateInlines()
+    };
+    
+    /// <summary>
+    /// Get the current inlines
+    /// </summary>
+    public InlineCollection TextInlines => ((TextBlock) Content).Inlines!;
+
+    /// <inheritdoc />
+    public double Priority { get; }
+
+    public CompletionData(string text)
+    {
+        Text = text;
+    }
+
+    /// <summary>
+    /// Create text block inline runs from text.
+    /// </summary>
+    private InlineCollection CreateInlines()
+    {
+        // Create a span for each character in the text.
+        var chars = Text.ToCharArray();
+        var inlines = new InlineCollection();
+        
+        foreach (var c in chars)
+        {
+            var run = new Run(c.ToString());
+            inlines.Add(run);
+        }
+
+        return inlines;
+    }
+    
+    /// <inheritdoc />
+    public void Complete(TextArea textArea, ISegment completionSegment, EventArgs insertionRequestEventArgs)
+    {
+        textArea.Document.Replace(completionSegment, Text);
+    }
+
+    /// <inheritdoc />
+    public void UpdateCharHighlighting(string searchText)
+    {
+        if (TextInlines is null)
+        {
+            throw new NullReferenceException("TextContent is null");
+        }
+        
+        Debug.WriteLine($"Updating char highlighting for {Text} with search text {searchText}");
+        
+        var defaultColor = ThemeColors.CompletionForegroundBrush;
+        var highlightColor = ThemeColors.CompletionSelectionForegroundBrush;
+        
+        // Match characters in the text with the search text from the start
+        foreach (var (i, currentChar) in Text.Enumerate())
+        {
+            var inline = TextInlines[i];
+            
+            // If longer than text, set to default color
+            if (i >= searchText.Length)
+            {
+                inline.Foreground = defaultColor;
+                continue;
+            }
+            
+            // If char matches, highlight it
+            if (currentChar == searchText[i])
+            {
+                inline.Foreground = highlightColor;
+            }
+            // For mismatch, set to default color
+            else
+            {
+                inline.Foreground = defaultColor;
+            }
+        }
+    }
+
+    /// <inheritdoc />
+    public void ResetCharHighlighting()
+    {
+        // TODO: handle light theme foreground variant
+        var defaultColor = ThemeColors.CompletionForegroundBrush;
+        
+        foreach (var inline in TextInlines)
+        {
+            inline.Foreground = defaultColor;
+        }
+    }
+}

StabilityMatrix.Avalonia/Controls/CodeCompletion/CompletionIcons.cs

@@ -0,0 +1,69 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using Projektanker.Icons.Avalonia;
+using StabilityMatrix.Avalonia.Models;
+using StabilityMatrix.Avalonia.Models.TagCompletion;
+using StabilityMatrix.Avalonia.Styles;
+
+namespace StabilityMatrix.Avalonia.Controls.CodeCompletion;
+
+[SuppressMessage("ReSharper", "MemberCanBePrivate.Global")]
+public static class CompletionIcons
+{
+    public static readonly IconData General = new()
+    {
+        FAIcon = "fa-solid fa-star-of-life",
+        Foreground = ThemeColors.LightSteelBlue,
+    };
+    
+    public static readonly IconData Artist = new()
+    {
+        FAIcon = "fa-solid fa-palette",
+        Foreground = ThemeColors.AmericanYellow,
+    };
+    
+    public static readonly IconData Character = new()
+    {
+        FAIcon = "fa-solid fa-user",
+        Foreground = ThemeColors.LuminousGreen,
+    };
+    
+    public static readonly IconData Copyright = new()
+    {
+        FAIcon = "fa-solid fa-copyright",
+        Foreground = ThemeColors.DeepMagenta,
+    };
+    
+    public static readonly IconData Species = new()
+    {
+        FAIcon = "fa-solid fa-dragon",
+        FontSize = 14,
+        Foreground = ThemeColors.HalloweenOrange,
+    };
+    
+    public static readonly IconData Invalid = new()
+    {
+        FAIcon = "fa-solid fa-question",
+        Foreground = ThemeColors.CompletionForegroundBrush,
+    };
+    
+    public static readonly IconData Keyword = new()
+    {
+        FAIcon = "fa-solid fa-key",
+        Foreground = ThemeColors.CompletionForegroundBrush,
+    };
+
+    public static IconData? GetIconForTagType(TagType tagType)
+    {
+        return tagType switch
+        {
+            TagType.General => General,
+            TagType.Artist => Artist,
+            TagType.Character => Character,
+            TagType.Species => Species,
+            TagType.Invalid => Invalid,
+            TagType.Copyright => Copyright,
+            _ => null
+        };
+    }
+}

StabilityMatrix.Avalonia/Controls/CodeCompletion/CompletionList.cs

@@ -0,0 +1,480 @@
+// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Controls.Primitives;
+using Avalonia.Input;
+using Avalonia.Interactivity;
+using Avalonia.Markup.Xaml.Templates;
+using AvaloniaEdit.Utils;
+
+namespace StabilityMatrix.Avalonia.Controls.CodeCompletion;
+
+/// <summary>
+/// The listbox used inside the CompletionWindow, contains CompletionListBox.
+/// </summary>
+[SuppressMessage("ReSharper", "MemberCanBePrivate.Global")]
+public class CompletionList : TemplatedControl
+{
+    public CompletionList()
+    {
+        DoubleTapped += OnDoubleTapped;
+
+        CompletionAcceptKeys = new[] { Key.Enter, Key.Tab, };
+    }
+
+    /// <summary>
+    /// If true, the CompletionList is filtered to show only matching items. Also enables search by substring.
+    /// If false, enables the old behavior: no filtering, search by string.StartsWith.
+    /// </summary>
+    public bool IsFiltering { get; set; } = true;
+
+    /// <summary>
+    /// Dependency property for <see cref="EmptyTemplate" />.
+    /// </summary>
+    public static readonly StyledProperty<ControlTemplate> EmptyTemplateProperty =
+        AvaloniaProperty.Register<CompletionList, ControlTemplate>(nameof(EmptyTemplate));
+
+    /// <summary>
+    /// Content of EmptyTemplate will be shown when CompletionList contains no items.
+    /// If EmptyTemplate is null, nothing will be shown.
+    /// </summary>
+    public ControlTemplate EmptyTemplate
+    {
+        get => GetValue(EmptyTemplateProperty);
+        set => SetValue(EmptyTemplateProperty, value);
+    }
+
+    /// <summary>
+    /// Dependency property for <see cref="FooterText" />.
+    /// </summary>
+    public static readonly StyledProperty<string?> FooterTextProperty = AvaloniaProperty.Register<CompletionList, string?>(
+        "FooterText", "Press Enter to insert, Tab to replace");
+
+    /// <summary>
+    /// Gets/Sets the text displayed in the footer of the completion list.
+    /// </summary>
+    public string? FooterText
+    {
+        get => GetValue(FooterTextProperty);
+        set => SetValue(FooterTextProperty, value);
+    }
+
+    /// <summary>
+    /// Is raised when the completion list indicates that the user has chosen
+    /// an entry to be completed.
+    /// </summary>
+    public event EventHandler? InsertionRequested;
+
+    /// <summary>
+    /// Raises the InsertionRequested event.
+    /// </summary>
+    public void RequestInsertion(EventArgs e)
+    {
+        InsertionRequested?.Invoke(this, e);
+    }
+
+    private CompletionListBox? _listBox;
+
+    protected override void OnApplyTemplate(TemplateAppliedEventArgs e)
+    {
+        base.OnApplyTemplate(e);
+
+        _listBox = e.NameScope.Find("PART_ListBox") as CompletionListBox;
+        if (_listBox is not null)
+        {
+            _listBox.ItemsSource = _completionData;
+        }
+    }
+
+    /// <summary>
+    /// Gets the list box.
+    /// </summary>
+    public CompletionListBox? ListBox
+    {
+        get
+        {
+            if (_listBox == null)
+                ApplyTemplate();
+            return _listBox;
+        }
+    }
+
+    /// <summary>
+    /// Gets or sets the array of keys that are supposed to request insertation of the completion
+    /// </summary>
+    public Key[] CompletionAcceptKeys { get; set; }
+
+    /// <summary>
+    /// Gets the scroll viewer used in this list box.
+    /// </summary>
+    public ScrollViewer? ScrollViewer => _listBox?.ScrollViewer;
+
+    private readonly ObservableCollection<ICompletionData> _completionData = new();
+
+    /// <summary>
+    /// Gets the list to which completion data can be added.
+    /// </summary>
+    public IList<ICompletionData> CompletionData => _completionData;
+
+    /// <inheritdoc/>
+    protected override void OnKeyDown(KeyEventArgs e)
+    {
+        base.OnKeyDown(e);
+        if (!e.Handled)
+        {
+            HandleKey(e);
+        }
+    }
+
+    /// <summary>
+    /// Handles a key press. Used to let the completion list handle key presses while the
+    /// focus is still on the text editor.
+    /// </summary>
+    public void HandleKey(KeyEventArgs e)
+    {
+        if (_listBox == null)
+            return;
+
+        // We have to do some key handling manually, because the default doesn't work with
+        // our simulated events.
+        // Also, the default PageUp/PageDown implementation changes the focus, so we avoid it.
+        switch (e.Key)
+        {
+            case Key.Down:
+                e.Handled = true;
+                _listBox.SelectIndex(_listBox.SelectedIndex + 1);
+                break;
+            case Key.Up:
+                e.Handled = true;
+                _listBox.SelectIndex(_listBox.SelectedIndex - 1);
+                break;
+            case Key.PageDown:
+                e.Handled = true;
+                _listBox.SelectIndex(_listBox.SelectedIndex + _listBox.VisibleItemCount);
+                break;
+            case Key.PageUp:
+                e.Handled = true;
+                _listBox.SelectIndex(_listBox.SelectedIndex - _listBox.VisibleItemCount);
+                break;
+            case Key.Home:
+                e.Handled = true;
+                _listBox.SelectIndex(0);
+                break;
+            case Key.End:
+                e.Handled = true;
+                _listBox.SelectIndex(_listBox.ItemCount - 1);
+                break;
+            default:
+                if (CompletionAcceptKeys.Contains(e.Key) && CurrentList.Count > 0)
+                {
+                    e.Handled = true;
+                    RequestInsertion(e);
+                }
+
+                break;
+        }
+    }
+
+    protected void OnDoubleTapped(object? sender, RoutedEventArgs e)
+    {
+        //TODO TEST
+        if (
+            ((AvaloniaObject?) e.Source)
+                .VisualAncestorsAndSelf()
+                .TakeWhile(obj => obj != this)
+                .Any(obj => obj is ListBoxItem)
+        )
+        {
+            e.Handled = true;
+            RequestInsertion(e);
+        }
+    }
+
+    /// <summary>
+    /// Gets/Sets the selected item.
+    /// </summary>
+    /// <remarks>
+    /// The setter of this property does not scroll to the selected item.
+    /// You might want to also call <see cref="ScrollIntoView"/>.
+    /// </remarks>
+    public ICompletionData? SelectedItem
+    {
+        get => _listBox?.SelectedItem as ICompletionData;
+        set
+        {
+            if (_listBox == null && value != null)
+                ApplyTemplate();
+            if (_listBox != null) // may still be null if ApplyTemplate fails, or if listBox and value both are null
+                _listBox.SelectedItem = value;
+        }
+    }
+
+    /// <summary>
+    /// Scrolls the specified item into view.
+    /// </summary>
+    public void ScrollIntoView(ICompletionData item)
+    {
+        if (_listBox == null)
+            ApplyTemplate();
+        _listBox?.ScrollIntoView(item);
+    }
+
+    /// <summary>
+    /// Occurs when the SelectedItem property changes.
+    /// </summary>
+    public event EventHandler<SelectionChangedEventArgs> SelectionChanged
+    {
+        add => AddHandler(SelectingItemsControl.SelectionChangedEvent, value);
+        remove => RemoveHandler(SelectingItemsControl.SelectionChangedEvent, value);
+    }
+
+    // SelectItem gets called twice for every typed character (once from FormatLine), this helps execute SelectItem only once
+    private string _currentText;
+
+    private ObservableCollection<ICompletionData>? _currentList;
+
+    public List<ICompletionData>? CurrentList => ListBox?.Items.Cast<ICompletionData>().ToList();
+
+    /// <summary>
+    /// Selects the best match, and filter the items if turned on using <see cref="IsFiltering" />.
+    /// </summary>
+    public void SelectItem(string text)
+    {
+        if (text == _currentText)
+            return;
+        if (_listBox == null)
+            ApplyTemplate();
+
+        if (IsFiltering)
+        {
+            SelectItemFiltering(text);
+        }
+        else
+        {
+            SelectItemWithStart(text);
+        }
+        _currentText = text;
+    }
+
+    /// <summary>
+    /// Filters CompletionList items to show only those matching given query, and selects the best match.
+    /// </summary>
+    private void SelectItemFiltering(string query)
+    {
+        // if the user just typed one more character, don't filter all data but just filter what we are already displaying
+        var listToFilter =
+            _currentList != null
+            && !string.IsNullOrEmpty(_currentText)
+            && !string.IsNullOrEmpty(query)
+            && query.StartsWith(_currentText, StringComparison.Ordinal)
+                ? _currentList
+                : _completionData;
+
+        var matchingItems =
+            from item in listToFilter
+            let quality = GetMatchQuality(item.Text, query)
+            where quality > 0
+            select new { Item = item, Quality = quality };
+
+        // e.g. "DateTimeKind k = (*cc here suggests DateTimeKind*)"
+        var suggestedItem =
+            _listBox.SelectedIndex != -1 ? (ICompletionData)_listBox.SelectedItem : null;
+
+        var listBoxItems = new ObservableCollection<ICompletionData>();
+        var bestIndex = -1;
+        var bestQuality = -1;
+        double bestPriority = 0;
+        var i = 0;
+        foreach (var matchingItem in matchingItems)
+        {
+            var priority =
+                matchingItem.Item == suggestedItem
+                    ? double.PositiveInfinity
+                    : matchingItem.Item.Priority;
+            var quality = matchingItem.Quality;
+            if (quality > bestQuality || quality == bestQuality && priority > bestPriority)
+            {
+                bestIndex = i;
+                bestPriority = priority;
+                bestQuality = quality;
+            }
+            // Add to listbox
+            listBoxItems.Add(matchingItem.Item);
+            // Update the character highlighting
+            matchingItem.Item.UpdateCharHighlighting(query);
+            i++;
+        }
+
+        _currentList = listBoxItems;
+        //_listBox.Items = null; Makes no sense? Tooltip disappeared because of this
+        _listBox.ItemsSource = listBoxItems;
+        SelectIndexCentered(bestIndex);
+    }
+
+    /// <summary>
+    /// Selects the item that starts with the specified query.
+    /// </summary>
+    private void SelectItemWithStart(string query)
+    {
+        if (string.IsNullOrEmpty(query))
+            return;
+
+        var suggestedIndex = _listBox.SelectedIndex;
+
+        var bestIndex = -1;
+        var bestQuality = -1;
+        double bestPriority = 0;
+        for (var i = 0; i < _completionData.Count; ++i)
+        {
+            var quality = GetMatchQuality(_completionData[i].Text, query);
+            if (quality < 0)
+                continue;
+
+            var priority = _completionData[i].Priority;
+            bool useThisItem;
+            if (bestQuality < quality)
+            {
+                useThisItem = true;
+            }
+            else
+            {
+                if (bestIndex == suggestedIndex)
+                {
+                    useThisItem = false;
+                }
+                else if (i == suggestedIndex)
+                {
+                    // prefer recommendedItem, regardless of its priority
+                    useThisItem = bestQuality == quality;
+                }
+                else
+                {
+                    useThisItem = bestQuality == quality && bestPriority < priority;
+                }
+            }
+            if (useThisItem)
+            {
+                bestIndex = i;
+                bestPriority = priority;
+                bestQuality = quality;
+            }
+        }
+        SelectIndexCentered(bestIndex);
+    }
+
+    private void SelectIndexCentered(int bestIndex)
+    {
+        if (bestIndex < 0)
+        {
+            _listBox.ClearSelection();
+        }
+        else
+        {
+            var firstItem = _listBox.FirstVisibleItem;
+            if (bestIndex < firstItem || firstItem + _listBox.VisibleItemCount <= bestIndex)
+            {
+                // CenterViewOn does nothing as CompletionListBox.ScrollViewer is null
+                _listBox.CenterViewOn(bestIndex);
+                _listBox.SelectIndex(bestIndex);
+            }
+            else
+            {
+                _listBox.SelectIndex(bestIndex);
+            }
+        }
+    }
+
+    private int GetMatchQuality(string itemText, string query)
+    {
+        if (itemText == null)
+            throw new ArgumentNullException(nameof(itemText), "ICompletionData.Text returned null");
+
+        // Qualities:
+        //  	8 = full match case sensitive
+        // 		7 = full match
+        // 		6 = match start case sensitive
+        //		5 = match start
+        //		4 = match CamelCase when length of query is 1 or 2 characters
+        // 		3 = match substring case sensitive
+        //		2 = match substring
+        //		1 = match CamelCase
+        //		-1 = no match
+        if (query == itemText)
+            return 8;
+        if (string.Equals(itemText, query, StringComparison.CurrentCultureIgnoreCase))
+            return 7;
+
+        if (itemText.StartsWith(query, StringComparison.CurrentCulture))
+            return 6;
+        if (itemText.StartsWith(query, StringComparison.CurrentCultureIgnoreCase))
+            return 5;
+
+        bool? camelCaseMatch = null;
+        if (query.Length <= 2)
+        {
+            camelCaseMatch = CamelCaseMatch(itemText, query);
+            if (camelCaseMatch == true)
+                return 4;
+        }
+
+        // search by substring, if filtering (i.e. new behavior) turned on
+        if (IsFiltering)
+        {
+            if (itemText.IndexOf(query, StringComparison.CurrentCulture) >= 0)
+                return 3;
+            if (itemText.IndexOf(query, StringComparison.CurrentCultureIgnoreCase) >= 0)
+                return 2;
+        }
+
+        if (!camelCaseMatch.HasValue)
+            camelCaseMatch = CamelCaseMatch(itemText, query);
+        if (camelCaseMatch == true)
+            return 1;
+
+        return -1;
+    }
+
+    private static bool CamelCaseMatch(string text, string query)
+    {
+        // We take the first letter of the text regardless of whether or not it's upper case so we match
+        // against camelCase text as well as PascalCase text ("cct" matches "camelCaseText")
+        var theFirstLetterOfEachWord = text.AsEnumerable()
+            .Take(1)
+            .Concat(text.AsEnumerable().Skip(1).Where(char.IsUpper));
+
+        var i = 0;
+        foreach (var letter in theFirstLetterOfEachWord)
+        {
+            if (i > query.Length - 1)
+                return true; // return true here for CamelCase partial match ("CQ" matches "CodeQualityAnalysis")
+            if (char.ToUpperInvariant(query[i]) != char.ToUpperInvariant(letter))
+                return false;
+            i++;
+        }
+        if (i >= query.Length)
+            return true;
+        return false;
+    }
+}

StabilityMatrix.Avalonia/Controls/CodeCompletion/CompletionListBox.cs

@@ -0,0 +1,109 @@
+// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using Avalonia.Controls;
+using Avalonia.Controls.Primitives;
+using AvaloniaEdit.Utils;
+
+namespace StabilityMatrix.Avalonia.Controls.CodeCompletion;
+
+/// <summary>
+/// The list box used inside the CompletionList.
+/// </summary>
+public class CompletionListBox : ListBox
+{
+    internal ScrollViewer ScrollViewer;
+
+    protected override void OnApplyTemplate(TemplateAppliedEventArgs e)
+    {
+        base.OnApplyTemplate(e);
+        ScrollViewer = e.NameScope.Find("PART_ScrollViewer") as ScrollViewer;
+    }
+
+    /// <summary>
+    /// Gets the number of the first visible item.
+    /// </summary>
+    public int FirstVisibleItem
+    {
+        get
+        {
+            if (ScrollViewer == null || ScrollViewer.Extent.Height == 0)
+            {
+                return 0;
+            }
+
+            return (int)(ItemCount * ScrollViewer.Offset.Y / ScrollViewer.Extent.Height);
+        }
+        set
+        {
+            value = value.CoerceValue(0, ItemCount - VisibleItemCount);
+            if (ScrollViewer != null)
+            {
+                ScrollViewer.Offset = ScrollViewer.Offset.WithY((double)value / ItemCount * ScrollViewer.Extent.Height);
+            }
+        }
+    }
+
+    /// <summary>
+    /// Gets the number of visible items.
+    /// </summary>
+    public int VisibleItemCount
+    {
+        get
+        {
+            if (ScrollViewer == null || ScrollViewer.Extent.Height == 0)
+            {
+                return 10;
+            }
+            return Math.Max(
+                3,
+                (int)Math.Ceiling(ItemCount * ScrollViewer.Viewport.Height
+                                  / ScrollViewer.Extent.Height));
+        }
+    }
+
+    /// <summary>
+    /// Removes the selection.
+    /// </summary>
+    public void ClearSelection()
+    {
+        SelectedIndex = -1;
+    }
+
+    /// <summary>
+    /// Selects the item with the specified index and scrolls it into view.
+    /// </summary>
+    public void SelectIndex(int index)
+    {
+        if (index >= ItemCount)
+            index = ItemCount - 1;
+        if (index < 0)
+            index = 0;
+        SelectedIndex = index;
+        ScrollIntoView(SelectedItem);
+    }
+
+    /// <summary>
+    /// Centers the view on the item with the specified index.
+    /// </summary>
+    public void CenterViewOn(int index)
+    {
+        FirstVisibleItem = index - VisibleItemCount / 2;
+    }
+}

StabilityMatrix.Avalonia/Controls/CodeCompletion/CompletionListThemes.axaml

@@ -0,0 +1,223 @@
+<ResourceDictionary
+    xmlns="https://github.com/avaloniaui"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:cc="clr-namespace:StabilityMatrix.Avalonia.Controls.CodeCompletion"
+    xmlns:icons="clr-namespace:Projektanker.Icons.Avalonia;assembly=Projektanker.Icons.Avalonia"
+    xmlns:mocks="clr-namespace:StabilityMatrix.Avalonia.DesignData"
+    xmlns:models="clr-namespace:StabilityMatrix.Avalonia.Models"
+    xmlns:ui="clr-namespace:FluentAvalonia.UI.Controls;assembly=FluentAvalonia">
+
+    <Design.PreviewWith>
+        <Panel Width="400" Height="600">
+            <Panel Width="350" Height="200">
+                <ContentPresenter Content="{x:Static mocks:DesignData.SampleCompletionList}" />
+            </Panel>
+        </Panel>
+
+    </Design.PreviewWith>
+
+    <!--  ReSharper disable once Xaml.StaticResourceNotResolved  -->
+    <ControlTheme
+        x:Key="{x:Type cc:CompletionListBox}"
+        BasedOn="{StaticResource {x:Type ListBox}}"
+        TargetType="cc:CompletionListBox">
+        <Setter Property="Margin" Value="0,2" />
+        <Setter Property="Padding" Value="0" />
+        <Setter Property="WrapSelection" Value="True" />
+        <Setter Property="ItemContainerTheme">
+            <!--  ReSharper disable once Xaml.StaticResourceNotResolved  -->
+            <ControlTheme TargetType="ListBoxItem">
+                <!--
+                    Modified from https://github.com/amwx/FluentAvalonia/blob/main/src/
+                    FluentAvalonia/Styling/ControlThemes/BasicControls/ListBoxStyles.axaml
+                -->
+
+                <Setter Property="Padding" Value="8,0,12,0" />
+
+                <Setter Property="FontFamily" Value="{DynamicResource ContentControlThemeFontFamily}" />
+                <Setter Property="FontSize" Value="{DynamicResource ControlContentThemeFontSize}" />
+                <Setter Property="Background" Value="{DynamicResource ListViewItemBackground}" />
+                <Setter Property="CornerRadius" Value="7" />
+                <Setter Property="Foreground" Value="{DynamicResource ListViewItemForeground}" />
+
+                <Setter Property="HorizontalContentAlignment" Value="Stretch" />
+                <Setter Property="VerticalContentAlignment" Value="Center" />
+                <Setter Property="MinWidth" Value="{DynamicResource ListViewItemMinWidth}" />
+                <Setter Property="Height" Value="26" />
+
+                <Setter Property="Template">
+                    <ControlTemplate>
+                        <Panel>
+                            <ContentPresenter
+                                Name="PART_ContentPresenter"
+                                Margin="2,0"
+                                Padding="{TemplateBinding Padding}"
+                                HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
+                                VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
+                                Background="{TemplateBinding Background}"
+                                BorderBrush="{TemplateBinding BorderBrush}"
+                                BorderThickness="{TemplateBinding BorderThickness}"
+                                Content="{TemplateBinding Content}"
+                                ContentTemplate="{TemplateBinding ContentTemplate}"
+                                CornerRadius="{TemplateBinding CornerRadius}" />
+                        </Panel>
+                    </ControlTemplate>
+                </Setter>
+
+                <!--<Style Selector="^:pointerover">
+                    <Style Selector="^ /template/ ContentPresenter#PART_ContentPresenter">
+                        <Setter Property="Background" Value="{DynamicResource ListViewItemBackgroundPointerOver}" />
+                    </Style>
+                    <Style Selector="^ /template/ ContentPresenter#PART_ContentPresenter">
+                        <Setter Property="Foreground" Value="{DynamicResource ListViewItemForegroundPointerOver}" />
+                    </Style>
+                </Style>-->
+
+                <Style Selector="^ /template/ ContentPresenter#PART_ContentPresenter">
+                    <Setter Property="Background" Value="{DynamicResource ListViewItemBackgroundPressed}" />
+                </Style>
+                <Style Selector="^ /template/ ContentPresenter">
+                    <Setter Property="Foreground" Value="{DynamicResource ListViewItemForegroundPressed}" />
+                </Style>
+
+
+                <Style Selector="^:selected">
+                    <Style Selector="^ /template/ ContentPresenter#PART_ContentPresenter">
+                        <Setter Property="Background" Value="{DynamicResource CompletionSelectionBackgroundBrush}" />
+                    </Style>
+                    <Style Selector="^ /template/ ContentPresenter">
+                        <Setter Property="Foreground" Value="{DynamicResource ListViewItemForegroundSelected}" />
+                    </Style>
+                    <!--  Disable selection indicator from fluent theme  -->
+                    <!--<Style Selector="^ /template/ Rectangle#SelectionIndicator">
+                        <Setter Property="IsVisible" Value="False" />
+                    </Style>-->
+                    <!--<Style Selector="^:not(:focus) /template/ ContentPresenter#PART_ContentPresenter">
+                        <Setter Property="Background" Value="{DynamicResource ListViewItemBackgroundSelected}" />
+                    </Style>
+                    <Style Selector="^:not(:focus) /template/ ContentPresenter#PART_ContentPresenter">
+                        <Setter Property="Foreground" Value="{DynamicResource ListViewItemForegroundSelected}" />
+                    </Style>-->
+
+                    <!--<Style Selector="^:pointerover">
+                        <Style Selector="^ /template/ ContentPresenter#PART_ContentPresenter">
+                            <Setter Property="Background" Value="{DynamicResource ListViewItemBackgroundSelectedPointerOver}" />
+                        </Style>
+                        <Style Selector="^ /template/ ContentPresenter">
+                            <Setter Property="Foreground" Value="{DynamicResource ListViewItemForegroundSelectedPointerOver}" />
+                        </Style>
+                    </Style>-->
+
+                    <Style Selector="^:pressed">
+                        <Style Selector="^ /template/ ContentPresenter#PART_ContentPresenter">
+                            <Setter Property="Background" Value="{DynamicResource ListViewItemBackgroundSelectedPressed}" />
+                        </Style>
+                        <Style Selector="^ /template/ ContentPresenter#PART_ContentPresenter">
+                            <Setter Property="Foreground" Value="{DynamicResource ListViewItemForegroundSelectedPressed}" />
+                        </Style>
+                    </Style>
+
+                    <!--<Style Selector="^:disabled /template/ Rectangle#SelectionIndicator">
+                        <Setter Property="Fill" Value="{DynamicResource ListViewItemSelectionIndicatorDisabledBrush}" />
+                    </Style>-->
+                </Style>
+
+            </ControlTheme>
+        </Setter>
+    </ControlTheme>
+
+    <ControlTheme x:Key="{x:Type cc:CompletionList}" TargetType="cc:CompletionList">
+
+        <Setter Property="Background" Value="{DynamicResource CompletionBackgroundBrush}" />
+        <Setter Property="BorderBrush" Value="{DynamicResource CompletionBorderBrush}" />
+        <Setter Property="BorderThickness" Value="1.5" />
+        <Setter Property="Padding" Value="0" />
+        <Setter Property="MinWidth" Value="{DynamicResource FlyoutThemeMinWidth}" />
+        <Setter Property="MaxWidth" Value="{DynamicResource FlyoutThemeMaxWidth}" />
+        <Setter Property="MinHeight" Value="{DynamicResource FlyoutThemeMinHeight}" />
+        <Setter Property="MaxHeight" Value="{DynamicResource FlyoutThemeMaxHeight}" />
+        <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto" />
+        <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto" />
+        <Setter Property="CornerRadius" Value="6" />
+        <Setter Property="FontSize" Value="{DynamicResource ControlContentThemeFontSize}" />
+        <Setter Property="FontFamily" Value="{DynamicResource ContentControlThemeFontFamily}" />
+
+        <Setter Property="Template">
+            <ControlTemplate>
+                <!--  BoxShadow="0 0 10 2 #BF000000"  -->
+                <ui:FABorder
+                    Padding="{DynamicResource FlyoutBorderThemePadding}"
+                    Background="{TemplateBinding Background}"
+                    BorderBrush="{TemplateBinding BorderBrush}"
+                    BorderThickness="{TemplateBinding BorderThickness}"
+                    CornerRadius="{TemplateBinding CornerRadius}">
+
+                    <Grid RowDefinitions="*,Auto">
+                        <!--  ReSharper disable once InconsistentNaming  -->
+                        <cc:CompletionListBox Name="PART_ListBox">
+                            <cc:CompletionListBox.ItemTemplate>
+                                <DataTemplate x:DataType="cc:ICompletionData">
+                                    <Grid ColumnDefinitions="20,Auto,*">
+                                        <Image
+                                            Width="16"
+                                            Height="16"
+                                            Margin="0,0,2,0"
+                                            IsVisible="{Binding Image, Converter={x:Static ObjectConverters.IsNotNull}}"
+                                            Source="{Binding Image}" />
+
+                                        <!--  Icon  -->
+                                        <Panel Grid.Column="0" 
+                                               IsVisible="{Binding Converter={x:Static ObjectConverters.IsNotNull}}"
+                                               DataContext="{Binding Icon}">
+                                            <icons:Icon
+                                                Margin="0,0,4,0"
+                                                FontSize="{Binding FontSize, TargetNullValue=12}"
+                                                Foreground="{Binding Foreground, TargetNullValue=Red, FallbackValue=Red}"
+                                                IsVisible="{Binding FAIcon, Converter={x:Static ObjectConverters.IsNotNull}}"
+                                                Value="{Binding FAIcon}" />
+                                        </Panel>
+
+                                        <!--  Main text  -->
+                                        <TextBlock
+                                            Grid.Column="1"
+                                            VerticalAlignment="Center"
+                                            FontFamily="Cascadia Code,Consolas,Menlo,Monospace"
+                                            FontSize="13"
+                                            Inlines="{Binding TextInlines}" />
+
+                                        <!--  Description Text  -->
+                                        <TextBlock
+                                            Grid.Column="2"
+                                            VerticalAlignment="Center"
+                                            FontFamily="Cascadia Code,Consolas,Menlo,Monospace"
+                                            FontSize="13"
+                                            Foreground="{DynamicResource CompletionSecondaryForegroundBrush}"
+                                            Text="{Binding Description}"
+                                            TextAlignment="Right" />
+                                        <!--<ContentPresenter Content="{Binding Content}" />-->
+                                    </Grid>
+                                </DataTemplate>
+                            </cc:CompletionListBox.ItemTemplate>
+                        </cc:CompletionListBox>
+
+                        <!--  Keybinding hints panel  -->
+                        <Panel
+                            Grid.Row="1"
+                            MinHeight="20"
+                            Background="{DynamicResource CompletionSecondaryBackgroundBrush}">
+                            <TextBlock
+                                Margin="10,3"
+                                FontSize="12"
+                                Foreground="{DynamicResource CompletionSecondaryForegroundBrush}"
+                                Text="{TemplateBinding FooterText}" />
+                        </Panel>
+                    </Grid>
+
+
+                </ui:FABorder>
+
+            </ControlTemplate>
+        </Setter>
+    </ControlTheme>
+
+</ResourceDictionary>

StabilityMatrix.Avalonia/Controls/CodeCompletion/CompletionWindow.axaml

@@ -0,0 +1,55 @@
+<Styles xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:controls="using:StabilityMatrix.Avalonia.Controls.CodeCompletion"
+        xmlns:ui="clr-namespace:FluentAvalonia.UI.Controls;assembly=FluentAvalonia">
+    
+    <!-- Style used for tooltip next to completion list box.  -->
+    <!--<Style Selector="ContentControl.ToolTip">
+        <Setter Property="BorderThickness" Value="{DynamicResource CompletionToolTipBorderThickness}" />
+        <Setter Property="BorderBrush" Value="{DynamicResource CompletionToolTipBorderBrush}" />
+        <Setter Property="Background" Value="{DynamicResource CompletionToolTipBackground}" />
+        <Setter Property="Foreground" Value="{DynamicResource CompletionToolTipForeground}" />
+        <Setter Property="Padding" Value="4,2" />
+    </Style>-->
+
+    
+    <!--<Style Selector="controls|CompletionWindow">
+        ~1~<Style Selector="^ /template/ ContentControl.ToolTip">
+            <Setter Property="BorderThickness" Value="{DynamicResource CompletionToolTipBorderThickness}" />
+            <Setter Property="BorderBrush" Value="{DynamicResource CompletionToolTipBorderBrush}" />
+            <Setter Property="Background" Value="{DynamicResource CompletionToolTipBackground}" />
+            <Setter Property="Foreground" Value="{DynamicResource CompletionToolTipForeground}" />
+            <Setter Property="Padding" Value="4,2" />
+
+        </Style>@1@
+        ~1~<Setter Property="Template">
+            <ControlTemplate>
+                <TextBlock Text="Templated Control" />
+            </ControlTemplate>
+        </Setter>@1@
+    </Style>-->
+    
+    <!--<Style Selector="controls|CompletionWindow">
+        <Setter Property="TransparencyLevelHint" Value="Transparent" />
+        <Setter Property="Background" Value="{x:Null}" />
+        <Setter Property="CornerRadius" Value="{DynamicResource OverlayCornerRadius}" />
+        <Setter Property="FontSize" Value="{DynamicResource ControlContentThemeFontSize}" />
+        <Setter Property="FontFamily" Value="{DynamicResource ContentControlThemeFontFamily}" />
+        <Setter Property="Template">
+            <ControlTemplate>
+                <LayoutTransformControl LayoutTransform="{TemplateBinding Transform}">
+                    <Panel>
+                        <Border Name="PART_TransparencyFallback" IsHitTestVisible="False" />
+                        <VisualLayerManager IsPopup="True">
+                            <ContentPresenter Name="PART_ContentPresenter"
+                                              Background="{TemplateBinding Background}"
+                                              ContentTemplate="{TemplateBinding ContentTemplate}"
+                                              Content="{TemplateBinding Content}"
+                                              Padding="{TemplateBinding Padding}" />
+                        </VisualLayerManager>
+                    </Panel>
+                </LayoutTransformControl>
+            </ControlTemplate>
+        </Setter>
+    </Style>-->
+</Styles>

StabilityMatrix.Avalonia/Controls/CodeCompletion/CompletionWindow.axaml.cs

@@ -0,0 +1,258 @@
+// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.Diagnostics;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Controls.Primitives;
+using Avalonia.Input;
+using Avalonia.Media;
+using AvaloniaEdit.Document;
+using AvaloniaEdit.Editing;
+
+namespace StabilityMatrix.Avalonia.Controls.CodeCompletion;
+
+/// <summary>
+/// The code completion window.
+/// </summary>
+public class CompletionWindow : CompletionWindowBase
+{
+    private PopupWithCustomPosition _toolTip;
+    private ContentControl _toolTipContent;
+    
+    
+    /// <summary>
+    /// Gets the completion list used in this completion window.
+    /// </summary>
+    public CompletionList CompletionList { get; }
+
+    /// <summary>
+    /// Creates a new code completion window.
+    /// </summary>
+    public CompletionWindow(TextArea textArea) : base(textArea)
+    {
+        CompletionList = new CompletionList();
+        // keep height automatic
+        CloseAutomatically = true;
+        MaxHeight = 225;
+        // Width = 175;
+        Width = 350;
+        Child = CompletionList;
+        // prevent user from resizing window to 0x0
+        MinHeight = 15;
+        MinWidth = 30;
+        
+        _toolTipContent = new ContentControl();
+        _toolTipContent.Classes.Add("ToolTip");
+
+        _toolTip = new PopupWithCustomPosition
+        {
+            IsLightDismissEnabled = true,
+            PlacementTarget = this,
+            // Placement = PlacementMode.RightEdgeAlignedTop,
+            Placement = PlacementMode.LeftEdgeAlignedBottom,
+            Child = _toolTipContent,
+        };
+
+        LogicalChildren.Add(_toolTip);
+
+        //_toolTip.Closed += (o, e) => ((Popup)o).Child = null;
+
+        AttachEvents();
+    }
+
+    protected override void OnClosed()
+    {
+        base.OnClosed();
+
+        if (_toolTip != null)
+        {
+            _toolTip.IsOpen = false;
+            _toolTip = null;
+            _toolTipContent = null;
+        }
+    }
+
+    #region ToolTip handling
+
+    private void CompletionList_SelectionChanged(object sender, SelectionChangedEventArgs e)
+    {
+        if (_toolTipContent == null) return;
+
+        var item = CompletionList.SelectedItem;
+        var description = item?.Description;
+        if (description != null)
+        {
+            if (description is string descriptionText)
+            {
+                _toolTipContent.Content = new TextBlock
+                {
+                    Text = descriptionText,
+                    TextWrapping = TextWrapping.Wrap
+                };
+            }
+            else
+            {
+                _toolTipContent.Content = description;
+            }
+
+            _toolTip.IsOpen = false; //Popup needs to be closed to change position
+
+            // Calculate offset for tooltip
+            var popupRoot = Host as PopupRoot;
+            if (CompletionList.CurrentList != null)
+            {
+                double yOffset = 0;
+                var itemContainer = CompletionList.ListBox.ContainerFromItem(item);
+                if (popupRoot != null && itemContainer != null)
+                {
+                    var position = itemContainer.TranslatePoint(new Point(0, 0), popupRoot);
+                    if (position.HasValue)
+                        yOffset = position.Value.Y;
+                }
+
+                _toolTip.Offset = new Point(2, yOffset);
+            }
+
+            _toolTip.PlacementTarget = popupRoot;
+            _toolTip.IsOpen = true;
+        }
+        else
+        {
+            _toolTip.IsOpen = false;
+        }
+    }
+
+    #endregion
+
+    private void CompletionList_InsertionRequested(object sender, EventArgs e)
+    {
+        Hide();
+        // The window must close before Complete() is called.
+        // If the Complete callback pushes stacked input handlers, we don't want to pop those when the CC window closes.
+        var item = CompletionList.SelectedItem;
+        item?.Complete(TextArea, new AnchorSegment(TextArea.Document, StartOffset, EndOffset - StartOffset), e);
+    }
+
+    private void AttachEvents()
+    {
+        CompletionList.InsertionRequested += CompletionList_InsertionRequested;
+        CompletionList.SelectionChanged += CompletionList_SelectionChanged;
+        TextArea.Caret.PositionChanged += CaretPositionChanged;
+        TextArea.PointerWheelChanged += TextArea_MouseWheel;
+        TextArea.TextInput += TextArea_PreviewTextInput;
+    }
+
+    /// <inheritdoc/>
+    protected override void DetachEvents()
+    {
+        CompletionList.InsertionRequested -= CompletionList_InsertionRequested;
+        CompletionList.SelectionChanged -= CompletionList_SelectionChanged;
+        TextArea.Caret.PositionChanged -= CaretPositionChanged;
+        TextArea.PointerWheelChanged -= TextArea_MouseWheel;
+        TextArea.TextInput -= TextArea_PreviewTextInput;
+        base.DetachEvents();
+    }
+
+    /// <inheritdoc/>
+    protected override void OnKeyDown(KeyEventArgs e)
+    {
+        base.OnKeyDown(e);
+        if (!e.Handled)
+        {
+            CompletionList.HandleKey(e);
+        }
+    }
+
+    private void TextArea_PreviewTextInput(object sender, TextInputEventArgs e)
+    {
+        e.Handled = RaiseEventPair(this, null, TextInputEvent,
+            new TextInputEventArgs { Text = e.Text });
+    }
+
+    private void TextArea_MouseWheel(object sender, PointerWheelEventArgs e)
+    {
+        e.Handled = RaiseEventPair(GetScrollEventTarget(),
+            null, PointerWheelChangedEvent, e);
+    }
+
+    private Control GetScrollEventTarget()
+    {
+        if (CompletionList == null)
+            return this;
+        return CompletionList.ScrollViewer ?? CompletionList.ListBox ?? (Control)CompletionList;
+    }
+
+    /// <summary>
+    /// Gets/Sets whether the completion window should close automatically.
+    /// The default value is true.
+    /// </summary>
+    public bool CloseAutomatically { get; set; }
+
+    /// <inheritdoc/>
+    protected override bool CloseOnFocusLost => CloseAutomatically;
+
+    /// <summary>
+    /// When this flag is set, code completion closes if the caret moves to the
+    /// beginning of the allowed range. This is useful in Ctrl+Space and "complete when typing",
+    /// but not in dot-completion.
+    /// Has no effect if CloseAutomatically is false.
+    /// </summary>
+    public bool CloseWhenCaretAtBeginning { get; set; }
+
+    private void CaretPositionChanged(object sender, EventArgs e)
+    {
+        Debug.WriteLine($"Caret Position changed: {e}");
+        var offset = TextArea.Caret.Offset;
+        if (offset == StartOffset)
+        {
+            if (CloseAutomatically && CloseWhenCaretAtBeginning)
+            {
+                Hide();
+            }
+            else
+            {
+                CompletionList.SelectItem(string.Empty);
+
+                if (CompletionList.ListBox.ItemCount == 0) IsVisible = false;
+                else IsVisible = true;
+            }
+            return;
+        }
+        if (offset < StartOffset || offset > EndOffset)
+        {
+            if (CloseAutomatically)
+            {
+                Hide();
+            }
+        }
+        else
+        {
+            var document = TextArea.Document;
+            if (document != null)
+            {
+                var newText = document.GetText(StartOffset, offset - StartOffset);
+                Debug.WriteLine("CaretPositionChanged newText: " + newText);
+                CompletionList.SelectItem(newText);
+
+                IsVisible = CompletionList.ListBox.ItemCount != 0;
+            }
+        }
+    }
+}

StabilityMatrix.Avalonia/Controls/CodeCompletion/CompletionWindowBase.cs

@@ -0,0 +1,421 @@
+// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Controls.Primitives;
+using Avalonia.Input;
+using Avalonia.Interactivity;
+using Avalonia.LogicalTree;
+using Avalonia.Threading;
+using Avalonia.VisualTree;
+using AvaloniaEdit;
+using AvaloniaEdit.Document;
+using AvaloniaEdit.Editing;
+using AvaloniaEdit.Rendering;
+
+namespace StabilityMatrix.Avalonia.Controls.CodeCompletion;
+
+/// <summary>
+/// Base class for completion windows. Handles positioning the window at the caret.
+/// </summary>
+public class CompletionWindowBase : Popup
+{
+    static CompletionWindowBase()
+    {
+        //BackgroundProperty.OverrideDefaultValue(typeof(CompletionWindowBase), Brushes.White);           
+    }
+
+    protected override Type StyleKeyOverride => typeof(PopupRoot);
+
+    /// <summary>
+    /// Gets the parent TextArea.
+    /// </summary>
+    public TextArea TextArea { get; }
+
+    private readonly Window _parentWindow;
+    private TextDocument _document;
+
+    /// <summary>
+    /// Gets/Sets the start of the text range in which the completion window stays open.
+    /// This text portion is used to determine the text used to select an entry in the completion list by typing.
+    /// </summary>
+    public int StartOffset { get; set; }
+
+    /// <summary>
+    /// Gets/Sets the end of the text range in which the completion window stays open.
+    /// This text portion is used to determine the text used to select an entry in the completion list by typing.
+    /// </summary>
+    public int EndOffset { get; set; }
+
+    /// <summary>
+    /// Gets whether the window was opened above the current line.
+    /// </summary>
+    protected bool IsUp { get; private set; }
+
+    /// <summary>
+    /// Creates a new CompletionWindowBase.
+    /// </summary>
+    public CompletionWindowBase(TextArea textArea) : base()
+    {
+        TextArea = textArea ?? throw new ArgumentNullException(nameof(textArea));
+        _parentWindow = textArea.GetVisualRoot() as Window;
+
+
+        AddHandler(PointerReleasedEvent, OnMouseUp, handledEventsToo: true);
+
+        StartOffset = EndOffset = TextArea.Caret.Offset;
+
+        PlacementTarget = TextArea.TextView;
+        Placement = PlacementMode.AnchorAndGravity;
+        PlacementAnchor = global::Avalonia.Controls.Primitives.PopupPositioning.PopupAnchor.TopLeft;
+        PlacementGravity = global::Avalonia.Controls.Primitives.PopupPositioning.PopupGravity.BottomRight;
+
+        //Deactivated += OnDeactivated; //Not needed?
+
+        Closed += (sender, args) => DetachEvents();
+
+        AttachEvents();
+
+        Initialize();
+    }
+
+    protected virtual void OnClosed()
+    {
+        DetachEvents();
+    }
+
+    private void Initialize()
+    {
+        if (_document != null && StartOffset != TextArea.Caret.Offset)
+        {
+            SetPosition(new TextViewPosition(_document.GetLocation(StartOffset)));
+        }
+        else
+        {
+            SetPosition(TextArea.Caret.Position);
+        }
+    }
+
+    public void Show()
+    {
+        UpdatePosition();
+
+        Open();
+        Height = double.NaN;
+        MinHeight = 0;
+    }
+
+    public void Hide()
+    {
+        Close();
+        OnClosed();
+    }
+
+    #region Event Handlers
+
+    private void AttachEvents()
+    {
+        ((ISetLogicalParent)this).SetParent(TextArea.GetVisualRoot() as ILogical);
+
+        _document = TextArea.Document;
+        if (_document != null)
+        {
+            _document.Changing += TextArea_Document_Changing;
+        }
+
+        // LostKeyboardFocus seems to be more reliable than PreviewLostKeyboardFocus - see SD-1729
+        TextArea.LostFocus += TextAreaLostFocus;
+        TextArea.TextView.ScrollOffsetChanged += TextViewScrollOffsetChanged;
+        TextArea.DocumentChanged += TextAreaDocumentChanged;
+        if (_parentWindow != null)
+        {
+            _parentWindow.PositionChanged += ParentWindow_LocationChanged;
+            _parentWindow.Deactivated += ParentWindow_Deactivated;
+        }
+
+        // close previous completion windows of same type
+        foreach (var x in TextArea.StackedInputHandlers.OfType<InputHandler>())
+        {
+            if (x.Window.GetType() == GetType())
+                TextArea.PopStackedInputHandler(x);
+        }
+
+        _myInputHandler = new InputHandler(this);
+        TextArea.PushStackedInputHandler(_myInputHandler);
+    }
+
+    /// <summary>
+    /// Detaches events from the text area.
+    /// </summary>
+    protected virtual void DetachEvents()
+    {
+        ((ISetLogicalParent)this).SetParent(null);
+
+        if (_document != null)
+        {
+            _document.Changing -= TextArea_Document_Changing;
+        }
+        TextArea.LostFocus -= TextAreaLostFocus;
+        TextArea.TextView.ScrollOffsetChanged -= TextViewScrollOffsetChanged;
+        TextArea.DocumentChanged -= TextAreaDocumentChanged;
+        if (_parentWindow != null)
+        {
+            _parentWindow.PositionChanged -= ParentWindow_LocationChanged;
+            _parentWindow.Deactivated -= ParentWindow_Deactivated;
+        }
+        TextArea.PopStackedInputHandler(_myInputHandler);
+    }
+
+    #region InputHandler
+
+    private InputHandler _myInputHandler;
+
+    /// <summary>
+    /// A dummy input handler (that justs invokes the default input handler).
+    /// This is used to ensure the completion window closes when any other input handler
+    /// becomes active.
+    /// </summary>
+    private sealed class InputHandler : TextAreaStackedInputHandler
+    {
+        internal readonly CompletionWindowBase Window;
+
+        public InputHandler(CompletionWindowBase window)
+            : base(window.TextArea)
+        {
+            Debug.Assert(window != null);
+            Window = window;
+        }
+
+        public override void Detach()
+        {
+            base.Detach();
+            Window.Hide();
+        }
+
+        public override void OnPreviewKeyDown(KeyEventArgs e)
+        {
+            // prevents crash when typing deadchar while CC window is open
+            if (e.Key == Key.DeadCharProcessed)
+                return;
+            e.Handled = RaiseEventPair(Window, null, KeyDownEvent,
+                new KeyEventArgs { Key = e.Key });
+        }
+
+        public override void OnPreviewKeyUp(KeyEventArgs e)
+        {
+            if (e.Key == Key.DeadCharProcessed)
+                return;
+            e.Handled = RaiseEventPair(Window, null, KeyUpEvent,
+                new KeyEventArgs { Key = e.Key });
+        }
+    }
+    #endregion
+
+    private void TextViewScrollOffsetChanged(object sender, EventArgs e)
+    {
+        ILogicalScrollable textView = TextArea;
+        var visibleRect = new Rect(textView.Offset.X, textView.Offset.Y, textView.Viewport.Width, textView.Viewport.Height);
+        //close completion window when the user scrolls so far that the anchor position is leaving the visible area
+        if (visibleRect.Contains(_visualLocation) || visibleRect.Contains(_visualLocationTop))
+        {
+            UpdatePosition();
+        }
+        else
+        {
+            Hide();
+        }
+    }
+
+    private void TextAreaDocumentChanged(object sender, EventArgs e)
+    {
+        Hide();
+    }
+
+    private void TextAreaLostFocus(object sender, RoutedEventArgs e)
+    {
+        Dispatcher.UIThread.Post(CloseIfFocusLost, DispatcherPriority.Background);
+    }
+
+    private void ParentWindow_Deactivated(object sender, EventArgs e)
+    {
+        Hide();
+    }
+
+    private void ParentWindow_LocationChanged(object sender, EventArgs e)
+    {
+        UpdatePosition();
+    }
+
+    /// <inheritdoc/>
+    private void OnDeactivated(object sender, EventArgs e)
+    {
+        Dispatcher.UIThread.Post(CloseIfFocusLost, DispatcherPriority.Background);
+    }
+
+    #endregion
+
+    /// <summary>
+    /// Raises a tunnel/bubble event pair for a control.
+    /// </summary>
+    /// <param name="target">The control for which the event should be raised.</param>
+    /// <param name="previewEvent">The tunneling event.</param>
+    /// <param name="event">The bubbling event.</param>
+    /// <param name="args">The event args to use.</param>
+    /// <returns>The <see cref="RoutedEventArgs.Handled"/> value of the event args.</returns>
+    [SuppressMessage("Microsoft.Design", "CA1030:UseEventsWhereAppropriate")]
+    protected static bool RaiseEventPair(Control target, RoutedEvent previewEvent, RoutedEvent @event, RoutedEventArgs args)
+    {
+        if (target == null)
+            throw new ArgumentNullException(nameof(target));
+        if (args == null)
+            throw new ArgumentNullException(nameof(args));
+        if (previewEvent != null)
+        {
+            args.RoutedEvent = previewEvent;
+            target.RaiseEvent(args);
+        }
+        args.RoutedEvent = @event ?? throw new ArgumentNullException(nameof(@event));
+        target.RaiseEvent(args);
+        return args.Handled;
+    }
+
+    // Special handler: handledEventsToo
+    private void OnMouseUp(object sender, PointerReleasedEventArgs e)
+    {
+        ActivateParentWindow();
+    }
+
+    /// <summary>
+    /// Activates the parent window.
+    /// </summary>
+    protected virtual void ActivateParentWindow()
+    {
+        _parentWindow?.Activate();
+    }
+
+    private void CloseIfFocusLost()
+    {
+        if (CloseOnFocusLost)
+        {
+            Debug.WriteLine("CloseIfFocusLost: this.IsFocues=" + IsFocused + " IsTextAreaFocused=" + IsTextAreaFocused);
+            if (!IsFocused && !IsTextAreaFocused)
+            {
+                Hide();
+            }
+        }
+    }
+
+    /// <summary>
+    /// Gets whether the completion window should automatically close when the text editor looses focus.
+    /// </summary>
+    protected virtual bool CloseOnFocusLost => true;
+
+    private bool IsTextAreaFocused
+    {
+        get
+        {
+            if (_parentWindow != null && !_parentWindow.IsActive)
+                return false;
+            return TextArea.IsFocused;
+        }
+    }
+
+    /// <inheritdoc/>
+    protected override void OnKeyDown(KeyEventArgs e)
+    {
+        base.OnKeyDown(e);
+        if (!e.Handled && e.Key == Key.Escape)
+        {
+            e.Handled = true;
+            Hide();
+        }
+    }
+
+    private Point _visualLocation;
+    private Point _visualLocationTop;
+
+    /// <summary>
+    /// Positions the completion window at the specified position.
+    /// </summary>
+    protected void SetPosition(TextViewPosition position)
+    {
+        var textView = TextArea.TextView;
+
+        _visualLocation = textView.GetVisualPosition(position, VisualYPosition.LineBottom);
+        _visualLocationTop = textView.GetVisualPosition(position, VisualYPosition.LineTop);
+
+        UpdatePosition();
+    }
+
+    /// <summary>
+    /// Updates the position of the CompletionWindow based on the parent TextView position and the screen working area.
+    /// It ensures that the CompletionWindow is completely visible on the screen.
+    /// </summary>
+    protected void UpdatePosition()
+    {
+        var textView = TextArea.TextView;
+
+        var position = _visualLocation - textView.ScrollOffset;
+
+        this.HorizontalOffset = position.X;
+        this.VerticalOffset = position.Y;
+    }
+
+    // TODO: check if needed
+    ///// <inheritdoc/>
+    //protected override void OnRenderSizeChanged(SizeChangedInfo sizeInfo)
+    //{
+    //    base.OnRenderSizeChanged(sizeInfo);
+    //    if (sizeInfo.HeightChanged && IsUp)
+    //    {
+    //        this.Top += sizeInfo.PreviousSize.Height - sizeInfo.NewSize.Height;
+    //    }
+    //}
+
+    /// <summary>
+    /// Gets/sets whether the completion window should expect text insertion at the start offset,
+    /// which not go into the completion region, but before it.
+    /// </summary>
+    /// <remarks>This property allows only a single insertion, it is reset to false
+    /// when that insertion has occurred.</remarks>
+    public bool ExpectInsertionBeforeStart { get; set; }
+
+    protected virtual void TextArea_Document_Changing(object? sender, DocumentChangeEventArgs e)
+    {
+        if (e.Offset + e.RemovalLength == StartOffset && e.RemovalLength > 0)
+        {
+            Hide(); // removal immediately in front of completion segment: close the window
+            // this is necessary when pressing backspace after dot-completion
+        }
+        if (e.Offset == StartOffset && e.RemovalLength == 0 && ExpectInsertionBeforeStart)
+        {
+            StartOffset = e.GetNewOffset(StartOffset, AnchorMovementType.AfterInsertion);
+            ExpectInsertionBeforeStart = false;
+        }
+        else
+        {
+            StartOffset = e.GetNewOffset(StartOffset, AnchorMovementType.BeforeInsertion);
+        }
+        EndOffset = e.GetNewOffset(EndOffset, AnchorMovementType.AfterInsertion);
+    }
+}

StabilityMatrix.Avalonia/Controls/CodeCompletion/ICompletionData.cs

@@ -0,0 +1,95 @@
+// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using Avalonia.Controls.Documents;
+using Avalonia.Media;
+using AvaloniaEdit.Document;
+using AvaloniaEdit.Editing;
+using FluentAvalonia.UI.Controls;
+using StabilityMatrix.Avalonia.Models;
+
+namespace StabilityMatrix.Avalonia.Controls.CodeCompletion;
+
+/// <summary>
+/// Describes an entry in the <see cref="AvaloniaEdit.CodeCompletion.CompletionList"/>.
+/// </summary>
+/// <remarks>
+/// Note that the CompletionList uses data binding against the properties in this interface.
+/// Thus, your implementation of the interface must use public properties; not explicit interface implementation.
+/// </remarks>
+public interface ICompletionData
+{
+	/// <summary>
+	/// Gets the text. This property is used to filter the list of visible elements.
+	/// </summary>
+	string Text { get; }
+	
+	/// <summary>
+	/// Gets the description.
+	/// </summary>
+	public string? Description { get; }
+	
+	/// <summary>
+	/// Gets the image.
+	/// </summary>
+	IImage? Image { get; }
+	
+	/// <summary>
+	/// Gets the icon shown on the left.
+	/// </summary>
+	IconData? Icon { get; }
+		
+	/// <summary>
+	/// The displayed content. This can be the same as 'Text', or a control if
+	/// you want to display rich content.
+	/// </summary>
+	object Content { get; }
+		
+	/// <summary>
+	/// Gets inline text fragments.
+	/// </summary>
+	InlineCollection TextInlines { get; }
+		
+	/// <summary>
+	/// Gets the priority. This property is used in the selection logic. You can use it to prefer selecting those items
+	/// which the user is accessing most frequently.
+	/// </summary>
+	double Priority { get; }
+		
+	/// <summary>
+	/// Perform the completion.
+	/// </summary>
+	/// <param name="textArea">The text area on which completion is performed.</param>
+	/// <param name="completionSegment">The text segment that was used by the completion window if
+	/// the user types (segment between CompletionWindow.StartOffset and CompletionWindow.EndOffset).</param>
+	/// <param name="insertionRequestEventArgs">The EventArgs used for the insertion request.
+	/// These can be TextCompositionEventArgs, KeyEventArgs, MouseEventArgs, depending on how
+	/// the insertion was triggered.</param>
+	void Complete(TextArea textArea, ISegment completionSegment, EventArgs insertionRequestEventArgs);
+
+	/// <summary>
+	/// Update the text character highlighting
+	/// </summary>
+	void UpdateCharHighlighting(string searchText);
+	
+	/// <summary>
+	/// Reset the text character highlighting
+	/// </summary>
+	void ResetCharHighlighting();
+}

StabilityMatrix.Avalonia/Controls/CodeCompletion/PopupWithCustomPosition.cs

@@ -0,0 +1,19 @@
+using Avalonia;
+using Avalonia.Controls.Primitives;
+
+namespace StabilityMatrix.Avalonia.Controls.CodeCompletion;
+
+internal class PopupWithCustomPosition : Popup
+{
+    public Point Offset
+    {
+        get => new(HorizontalOffset, VerticalOffset);
+        set
+        {
+            HorizontalOffset = value.X;
+            VerticalOffset = value.Y;
+
+            // this.Revalidate(VerticalOffsetProperty);
+        }
+    }
+}

StabilityMatrix.Avalonia/Controls/PromptCard.axaml

@@ -4,6 +4,8 @@
         xmlns:mocks="clr-namespace:StabilityMatrix.Avalonia.DesignData"
         xmlns:avaloniaEdit="https://github.com/avaloniaui/avaloniaedit"
         xmlns:vmInference="clr-namespace:StabilityMatrix.Avalonia.ViewModels.Inference"
+        xmlns:i="clr-namespace:Avalonia.Xaml.Interactivity;assembly=Avalonia.Xaml.Interactivity"
+        xmlns:behaviors="clr-namespace:StabilityMatrix.Avalonia.Behaviors"
         xmlns:icons="clr-namespace:Projektanker.Icons.Avalonia;assembly=Projektanker.Icons.Avalonia"
         x:DataType="vmInference:PromptCardViewModel">
     <Design.PreviewWith>
@@ -64,8 +66,12 @@
                                 <avaloniaEdit:TextEditor
                                     x:Name="PromptEditor"
                                     Document="{Binding PromptDocument}"
-                                    FontFamily="Cascadia Code,Consolas,Menlo,Monospace"/>
-                            
+                                    FontFamily="Cascadia Code,Consolas,Menlo,Monospace">
+                                    <i:Interaction.Behaviors>
+                                        <behaviors:TextEditorCompletionBehavior/>
+                                    </i:Interaction.Behaviors>
+                                </avaloniaEdit:TextEditor>
+
                             </ExperimentalAcrylicBorder>
                         </Grid>
                         
@@ -93,8 +99,12 @@
                                 <avaloniaEdit:TextEditor
                                     x:Name="NegativePromptEditor"
                                     Document="{Binding NegativePromptDocument}"
-                                    FontFamily="Cascadia Code,Consolas,Menlo,Monospace"/>
-                            
+                                    FontFamily="Cascadia Code,Consolas,Menlo,Monospace">
+                                    <i:Interaction.Behaviors>
+                                        <behaviors:TextEditorCompletionBehavior/>
+                                    </i:Interaction.Behaviors>
+                                </avaloniaEdit:TextEditor>
+
                             </ExperimentalAcrylicBorder>
                         </Grid>
                     </Grid>

StabilityMatrix.Avalonia/DesignData/DesignData.cs

@@ -5,8 +5,11 @@ using System.Collections.ObjectModel;
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Net.Http;
+using AvaloniaEdit.Utils;
 using Microsoft.Extensions.DependencyInjection;
+using StabilityMatrix.Avalonia.Controls.CodeCompletion;
 using StabilityMatrix.Avalonia.Models;
+using StabilityMatrix.Avalonia.Models.TagCompletion;
 using StabilityMatrix.Avalonia.Services;
 using StabilityMatrix.Avalonia.ViewModels;
 using StabilityMatrix.Avalonia.ViewModels.Dialogs;
@@ -430,6 +433,26 @@ public static class DesignData
     public static BatchSizeCardViewModel BatchSizeCardViewModel =>
         DialogFactory.Get<BatchSizeCardViewModel>();
 
+    public static IList<ICompletionData> SampleCompletionData => new List<ICompletionData>
+    {
+        new TagCompletionData("test1", TagType.General),
+        new TagCompletionData("test2", TagType.Artist),
+        new TagCompletionData("test3", TagType.Character),
+        new TagCompletionData("test4", TagType.Copyright),
+        new TagCompletionData("test5", TagType.Species),
+        new TagCompletionData("test_unknown", TagType.Invalid),
+    };
+    
+    public static CompletionList SampleCompletionList
+    {
+        get
+        {
+            var list = new CompletionList();
+            list.CompletionData.AddRange(SampleCompletionData);
+            return list;
+        }
+    }
+
     public static Indexer Types => new();
 
     public class Indexer

StabilityMatrix.Avalonia/Models/IconData.cs

@@ -0,0 +1,12 @@
+using Avalonia.Media;
+
+namespace StabilityMatrix.Avalonia.Models;
+
+public record IconData
+{
+    public string? FAIcon { get; init; }
+    
+    public int? FontSize { get; init; }
+    
+    public SolidColorBrush? Foreground { get; init; }
+}

StabilityMatrix.Avalonia/Models/TagCompletion/TagCompletionData.cs

@@ -0,0 +1,17 @@
+using StabilityMatrix.Avalonia.Controls.CodeCompletion;
+using StabilityMatrix.Core.Extensions;
+
+namespace StabilityMatrix.Avalonia.Models.TagCompletion;
+
+public class TagCompletionData : CompletionData
+{
+    protected TagType TagType { get; }
+    
+    /// <inheritdoc />
+    public TagCompletionData(string text, TagType tagType) : base(text)
+    {
+        TagType = tagType;
+        Icon = CompletionIcons.GetIconForTagType(tagType) ?? CompletionIcons.Invalid;
+        Description = tagType.GetStringValue();
+    }
+}

StabilityMatrix.Avalonia/Models/TagCompletion/TagType.cs

@@ -0,0 +1,38 @@
+using System.Text.Json.Serialization;
+using StabilityMatrix.Core.Converters.Json;
+
+namespace StabilityMatrix.Avalonia.Models.TagCompletion;
+
+[JsonConverter(typeof(DefaultUnknownEnumConverter<TagType>))]
+public enum TagType
+{
+    Unknown,
+    Invalid,
+    General,
+    Artist,
+    Copyright,
+    Character,
+    Species,
+    Meta,
+    Lore
+}
+
+public static class TagTypeExtensions
+{
+    public static TagType FromE621(int tag)
+    {
+        return tag switch
+        {
+            -1 => TagType.Invalid,
+            0 => TagType.General,
+            1 => TagType.Artist,
+            3 => TagType.Copyright,
+            4 => TagType.Character,
+            5 => TagType.Species,
+            6 => TagType.Invalid,
+            7 => TagType.Meta,
+            8 => TagType.Lore,
+            _ => TagType.Unknown
+        };
+    }
+}

StabilityMatrix.Avalonia/Styles/ThemeColors.axaml

@@ -1,6 +1,7 @@
 <ResourceDictionary xmlns="https://github.com/avaloniaui"
-                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
-    <!-- Add Resources Here -->
+                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+                    xmlns:sty="clr-namespace:FluentAvalonia.Styling;assembly=FluentAvalonia">
+    <!-- Static colors -->
     <Color x:Key="ThemePrimaryColor">#333333</Color>
     <Color x:Key="ThemeDarkDarkRedColor">#952923</Color>
     <Color x:Key="ThemeDarkRedColor">#C2362E</Color>
@@ -30,4 +31,38 @@
     <Color x:Key="ThemeBrownColor">#795548</Color>
     <Color x:Key="ThemeGreyColor">#9E9E9E</Color>
     <Color x:Key="ThemeBlueGreyColor">#607D8B</Color>
+    
+    <!-- Dark / light dynamic colors -->
+    <ResourceDictionary.ThemeDictionaries>
+        <ResourceDictionary x:Key="Default">
+            <SolidColorBrush x:Key="CompletionBorderBrush" Color="#43454A"/>
+            <SolidColorBrush x:Key="CompletionBackgroundBrush" Color="#2B2D30"/>
+            <SolidColorBrush x:Key="CompletionSecondaryBackgroundBrush" Color="#393B40"/>
+            <SolidColorBrush x:Key="CompletionForegroundBrush" Color="#B4B8BF"/>
+            <SolidColorBrush x:Key="CompletionSecondaryForegroundBrush" Color="#878B8D"/>
+            <SolidColorBrush x:Key="CompletionSelectionBackgroundBrush" Color="#2E436E"/>
+            <SolidColorBrush x:Key="CompletionSelectionForegroundBrush" Color="#5389F4"/>
+        </ResourceDictionary>
+        
+        <ResourceDictionary x:Key="Dark">
+            <SolidColorBrush x:Key="CompletionBorderBrush" Color="#43454A"/>
+            <SolidColorBrush x:Key="CompletionBackgroundBrush" Color="#2B2D30"/>
+            <SolidColorBrush x:Key="CompletionSecondaryBackgroundBrush" Color="#393B40"/>
+            <SolidColorBrush x:Key="CompletionForegroundBrush" Color="#B4B8BF"/>
+            <SolidColorBrush x:Key="CompletionSecondaryForegroundBrush" Color="#878B8D"/>
+            <SolidColorBrush x:Key="CompletionSelectionBackgroundBrush" Color="#2E436E"/>
+            <SolidColorBrush x:Key="CompletionSelectionForegroundBrush" Color="#5389F4"/>
+        </ResourceDictionary>
+        
+        <ResourceDictionary x:Key="{x:Static sty:FluentAvaloniaTheme.HighContrastTheme}">
+            <SolidColorBrush x:Key="CompletionBorderBrush" Color="#43454A"/>
+            <SolidColorBrush x:Key="CompletionBackgroundBrush" Color="#2B2D30"/>
+            <SolidColorBrush x:Key="CompletionSecondaryBackgroundBrush" Color="#393B40"/>
+            <SolidColorBrush x:Key="CompletionForegroundBrush" Color="#B4B8BF"/>
+            <SolidColorBrush x:Key="CompletionSecondaryForegroundBrush" Color="#878B8D"/>
+            <SolidColorBrush x:Key="CompletionSelectionBackgroundBrush" Color="#2E436E"/>
+            <SolidColorBrush x:Key="CompletionSelectionForegroundBrush" Color="#5389F4"/>
+        </ResourceDictionary>
+    </ResourceDictionary.ThemeDictionaries>
+    
 </ResourceDictionary>

StabilityMatrix.Avalonia/Styles/ThemeColors.cs

@@ -1,4 +1,5 @@
-using Avalonia.Media;
+using Avalonia;
+using Avalonia.Media;
 
 namespace StabilityMatrix.Avalonia.Styles;
 
@@ -7,4 +8,17 @@ public static class ThemeColors
     public static readonly SolidColorBrush ThemeGreen = SolidColorBrush.Parse("#4caf50");
     public static readonly SolidColorBrush ThemeRed = SolidColorBrush.Parse("#f44336");
     public static readonly SolidColorBrush ThemeYellow = SolidColorBrush.Parse("#ffeb3b");
+    
+    public static readonly SolidColorBrush AmericanYellow = SolidColorBrush.Parse("#f2ac08");
+    public static readonly SolidColorBrush HalloweenOrange = SolidColorBrush.Parse("#ed5D1f");
+    public static readonly SolidColorBrush LightSteelBlue = SolidColorBrush.Parse("#b4c7d9");
+    public static readonly SolidColorBrush DeepMagenta = SolidColorBrush.Parse("#dd00dd");
+    public static readonly SolidColorBrush LuminousGreen = SolidColorBrush.Parse("#00aa00");
+
+    public static readonly SolidColorBrush CompletionSelectionBackgroundBrush = 
+        SolidColorBrush.Parse("#2E436E");
+    public static readonly SolidColorBrush CompletionSelectionForegroundBrush = 
+        SolidColorBrush.Parse("#5389F4");
+    public static readonly SolidColorBrush CompletionForegroundBrush =
+        SolidColorBrush.Parse("#B4B8BF");
 }

StabilityMatrix.Avalonia/ViewModels/Inference/InferenceTextToImageViewModel.cs

@@ -286,7 +286,7 @@ public partial class InferenceTextToImageViewModel : InferenceTabViewModelBase
         // Connect progress handler
         // client.ProgressUpdateReceived += OnProgressUpdateReceived;
         client.PreviewImageReceived += OnPreviewImageReceived;
-
+        
         ComfyTask? promptTask = null;
         try
         {
@@ -356,12 +356,11 @@ public partial class InferenceTextToImageViewModel : InferenceTabViewModelBase
                 await using var fileStream = gridPath.Info.OpenWrite();
                 await fileStream.WriteAsync(grid.Encode().ToArray(), cancellationToken);
                 
-                // Insert to start of gallery
+                // Insert to start of images
                 ImageGalleryCardViewModel.ImageSources.Add(new ImageSource(gridPath));
-                // var bitmaps = (await outputImages.SelectAsync(async i => await i.GetBitmapAsync())).ToImmutableArray();
             }
             
-            // Insert rest of images
+            // Add rest of images
             ImageGalleryCardViewModel.ImageSources.AddRange(outputImages);
         }
         finally