Use format detector feature for TextViewer

QuickLook.Plugin/QuickLook.Plugin.TextViewer/Detectors/EncodingDetector.cs

@@ -0,0 +1,89 @@
+// Copyright © 2017-2025 QL-Win Contributors
+//
+// This file is part of QuickLook program.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+using System.ComponentModel.Composition;
+using System.Linq;
+using System.Text;
+using UtfUnknown;
+
+namespace QuickLook.Plugin.TextViewer.Detectors;
+
+[Export]
+public class EncodingDetector
+{
+    public static Encoding DetectFromBytes(byte[] bytes)
+    {
+        var result = CharsetDetector.DetectFromBytes(bytes);
+        var encoding = result.DoubleDetectFromResult(bytes); // Fix issues
+
+        return encoding;
+    }
+}
+
+file static class DetectionExtensions
+{
+    public static Encoding DoubleDetectFromResult(this DetectionResult result, byte[] buffer)
+    {
+        // Determine the highest confidence encoding, or fallback to ANSI
+        var encoding = result.Detected?.Encoding ?? Encoding.Default;
+
+        // When mixing encodings, one of the encodings may gain higher confidence
+        // In this case, we should return to encodings UTF8 / UTF32 / ANSI
+        // https://github.com/QL-Win/QuickLook/issues/769
+        if (encoding != Encoding.UTF8 && encoding != Encoding.UTF32 && encoding != Encoding.Default)
+        {
+            if (result.Details.Any(detail => detail.Encoding == Encoding.UTF8))
+            {
+                encoding = Encoding.UTF8;
+            }
+            else if (result.Details.Any(detail => detail.Encoding == Encoding.UTF32))
+            {
+                encoding = Encoding.UTF32;
+            }
+            else if (result.Details.Any(detail => detail.Encoding == Encoding.Default))
+            {
+                encoding = Encoding.Default;
+            }
+        }
+
+        // When the text is too short and lacks a BOM
+        // In this case, we should fallback to an encoding if it is not recognized as UTF8 / UTF32 / ANSI
+        // https://github.com/QL-Win/QuickLook/issues/471
+        // https://github.com/QL-Win/QuickLook/issues/600
+        // https://github.com/QL-Win/QuickLook/issues/954
+        if (buffer.Length <= 50)
+        {
+            if (encoding != Encoding.UTF8 && encoding != Encoding.UTF32 && encoding != Encoding.Default)
+            {
+                if (!Encoding.UTF8.GetString(buffer).Contains("\uFFFD"))
+                {
+                    encoding = Encoding.UTF8;
+                }
+                else if (!Encoding.UTF32.GetString(buffer).Contains("\uFFFD"))
+                {
+                    encoding = Encoding.UTF32;
+                }
+                else if (!Encoding.Default.GetString(buffer).Contains("\uFFFD"))
+                {
+                    encoding = Encoding.Default;
+                }
+            }
+        }
+
+        return encoding;
+    }
+}

QuickLook.Plugin/QuickLook.Plugin.TextViewer/Detectors/FormatDetector.cs

@@ -0,0 +1,48 @@
+// Copyright © 2017-2025 QL-Win Contributors
+//
+// This file is part of QuickLook program.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+using System.Linq;
+
+namespace QuickLook.Plugin.TextViewer.Detectors;
+
+public class FormatDetector
+{
+    public static FormatDetector Instance { get; } = new();
+
+    internal IFormatDetector[] TextDetectors =
+    [
+        new XMLDetector(),
+        new JSONDetector(),
+    ];
+
+    public static IFormatDetector Detect(string text)
+    {
+        if (string.IsNullOrWhiteSpace(text)) return null;
+
+        return Instance.TextDetectors.Where(detector => detector.Detect(text))
+            .FirstOrDefault();
+    }
+}
+
+public interface IFormatDetector
+{
+    public string Name { get; }
+
+    public string Extension { get; }
+
+    public bool Detect(string text);
+}

QuickLook.Plugin/QuickLook.Plugin.TextViewer/Detectors/JSONDetector.cs

@@ -0,0 +1,52 @@
+// Copyright © 2017-2025 QL-Win Contributors
+//
+// This file is part of QuickLook program.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+using System.Text.RegularExpressions;
+
+namespace QuickLook.Plugin.TextViewer.Detectors;
+
+public class JSONDetector : IFormatDetector
+{
+    public string Name => "JSON";
+
+    public string Extension => ".json";
+
+    public bool Detect(string text)
+    {
+        if (string.IsNullOrWhiteSpace(text)) return false;
+
+        // TODO: Use AsSpan to improve
+
+        var trimmedStart = text.TrimStart();
+
+        if (trimmedStart.StartsWith("{") || trimmedStart.StartsWith("["))
+        {
+            var trimmedEnd = text.TrimEnd();
+
+            if (trimmedEnd.EndsWith("}") || trimmedEnd.EndsWith("]"))
+            {
+                // At least one key exists
+                if (Regex.IsMatch(text, @"""[^""]+""\s*:"))
+                {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+}

QuickLook.Plugin/QuickLook.Plugin.TextViewer/Detectors/XMLDetector.cs

@@ -0,0 +1,34 @@
+// Copyright © 2017-2025 QL-Win Contributors
+//
+// This file is part of QuickLook program.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+using System.Text.RegularExpressions;
+
+namespace QuickLook.Plugin.TextViewer.Detectors;
+
+public class XMLDetector : IFormatDetector
+{
+    internal Regex Signature { get; } = new(@"<\?xml\b[^>]*\bversion\s*=\s*""[^""]*""[^\?>]*\?>", RegexOptions.IgnoreCase);
+
+    public string Name => "XML";
+
+    public string Extension => ".xml";
+
+    public bool Detect(string text)
+    {
+        return Signature.IsMatch(text);
+    }
+}

QuickLook.Plugin/QuickLook.Plugin.TextViewer/Plugin.cs

@@ -16,20 +16,14 @@
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 using ICSharpCode.AvalonEdit;
-using ICSharpCode.AvalonEdit.Highlighting;
-using ICSharpCode.AvalonEdit.Highlighting.Xshd;
-using QuickLook.Common.Helpers;
 using QuickLook.Common.Plugin;
+using QuickLook.Plugin.TextViewer.Themes;
 using System;
 using System.Collections.Generic;
-using System.Diagnostics;
 using System.IO;
 using System.Linq;
-using System.Reflection;
 using System.Windows;
 using System.Windows.Controls;
-using System.Windows.Media;
-using System.Xml;
 
 namespace QuickLook.Plugin.TextViewer;
 
@@ -37,9 +31,6 @@ public class Plugin : IViewer
 {
     private TextViewerPanel _tvp;
 
-    private static HighlightingManager _hlmLight;
-    private static HighlightingManager _hlmDark;
-
     public int Priority => -5;
 
     public void Init()
@@ -47,9 +38,7 @@ public class Plugin : IViewer
         // pre-load
         var _ = new TextEditor();
 
-        InitHighlightingManager();
-        AddHighlightingManager(_hlmLight, "Light");
-        AddHighlightingManager(_hlmDark, "Dark");
+        HighlightingThemeManager.Initialize();
 
         // Implementation of the Search Panel Styled with Fluent Theme
         {
@@ -71,7 +60,7 @@ public class Plugin : IViewer
         if (Directory.Exists(path))
             return false;
 
-        if (new[] { ".txt", ".rtf" }.Any(path.ToLower().EndsWith))
+        if (new[] { ".txt", ".rtf" }.Any(ext => path.EndsWith(ext, StringComparison.OrdinalIgnoreCase)))
             return true;
 
         // if there is a matched highlighting scheme (by file extension), treat it as a plain text file
@@ -94,7 +83,7 @@ public class Plugin : IViewer
 
     public void View(string path, ContextObject context)
     {
-        if (path.ToLower().EndsWith(".rtf"))
+        if (path.EndsWith(".rtf", StringComparison.OrdinalIgnoreCase))
         {
             var rtfBox = new RichTextBox();
             FileStream fs = File.OpenRead(path);
@@ -108,9 +97,8 @@ public class Plugin : IViewer
         }
         else
         {
-            _tvp = new TextViewerPanel(path, context);
-            AssignHighlightingManager(path, _tvp, context);
-
+            _tvp = new TextViewerPanel();
+            _tvp.LoadFileAsync(path, context);
             context.ViewerContent = _tvp;
         }
         context.Title = $"{Path.GetFileName(path)}";
@@ -130,123 +118,4 @@ public class Plugin : IViewer
 
         return true;
     }
-
-    private void AddHighlightingManager(HighlightingManager hlm, string dirName)
-    {
-        var assemblyPath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
-        if (string.IsNullOrEmpty(assemblyPath))
-            return;
-
-        var syntaxPath = Path.Combine(assemblyPath, "Syntax", dirName);
-        if (!Directory.Exists(syntaxPath))
-            return;
-
-        foreach (var file in Directory.EnumerateFiles(syntaxPath, "*.xshd").OrderBy(f => f))
-        {
-            try
-            {
-                Debug.WriteLine(file);
-                var ext = Path.GetFileNameWithoutExtension(file);
-                using Stream s = File.OpenRead(Path.GetFullPath(file));
-                using var reader = new XmlTextReader(s);
-                var xshd = HighlightingLoader.LoadXshd(reader);
-                var highlightingDefinition = HighlightingLoader.Load(xshd, hlm);
-                if (xshd.Extensions.Count > 0)
-                    hlm.RegisterHighlighting(ext, [.. xshd.Extensions], highlightingDefinition);
-            }
-            catch (Exception e)
-            {
-                ProcessHelper.WriteLog(e.ToString());
-            }
-        }
-    }
-
-    private void InitHighlightingManager()
-    {
-        _hlmLight = new HighlightingManager();
-        _hlmDark = new HighlightingManager();
-
-        Assembly assembly = Assembly.GetExecutingAssembly();
-        string[] resourceNames = assembly.GetManifestResourceNames();
-
-        foreach (var resourceName in resourceNames.Where(name => name.Contains(".Syntax.")))
-        {
-            using Stream s = assembly.GetManifestResourceStream(resourceName);
-
-            if (s == null)
-                continue;
-
-            Debug.WriteLine(resourceName);
-
-            try
-            {
-                var hlm = resourceName.Contains(".Syntax.Dark.") ? _hlmDark : _hlmLight;
-                var name = EmbeddedResource.GetFileNameWithoutExtension(resourceName);
-                using var reader = new XmlTextReader(s);
-                var xshd = HighlightingLoader.LoadXshd(reader);
-                var highlightingDefinition = HighlightingLoader.Load(xshd, hlm);
-                if (xshd.Extensions.Count > 0)
-                    hlm.RegisterHighlighting(name, [.. xshd.Extensions], highlightingDefinition);
-            }
-            catch (Exception e)
-            {
-                ProcessHelper.WriteLog(e.ToString());
-            }
-        }
-    }
-
-    private void AssignHighlightingManager(string path, TextViewerPanel tvp, ContextObject context)
-    {
-        var def = _hlmDark.GetDefinitionByExtension(Path.GetExtension(path));
-        var darkThemeAllowed = SettingHelper.Get("AllowDarkTheme", def != null, "QuickLook.Plugin.TextViewer");
-        var isDark = darkThemeAllowed && OSThemeHelper.AppsUseDarkTheme();
-
-        tvp.HighlightingManager = isDark ? _hlmDark : _hlmLight;
-        if (isDark)
-        {
-            tvp.Background = Brushes.Transparent;
-            tvp.SetResourceReference(Control.ForegroundProperty, "WindowTextForeground");
-        }
-        else
-        {
-            // if os dark mode, but not AllowDarkTheme, make background light
-            tvp.Background = OSThemeHelper.AppsUseDarkTheme()
-                ? new SolidColorBrush(Color.FromArgb(175, 255, 255, 255))
-                : Brushes.Transparent;
-        }
-    }
-}
-
-file static class EmbeddedResource
-{
-    public static string GetFileNameWithoutExtension(string resourceName)
-    {
-        // Requires the embedded resource file name
-        // must have a file extension and have only one '.' character
-        int start = int.MinValue, end = int.MinValue;
-
-        for (int i = resourceName.Length - 1; i >= 0; i--)
-        {
-            if (resourceName[i] == '.')
-            {
-                if (end == int.MinValue)
-                {
-                    end = i;
-                    continue;
-                }
-
-                if (start == int.MinValue)
-                {
-                    start = i + 1; // Exinclude '.' character
-                    break;
-                }
-            }
-        }
-
-        if ((start != int.MinValue) && (end != int.MinValue))
-        {
-            return resourceName.Substring(start, end - start);
-        }
-        return resourceName;
-    }
 }

QuickLook.Plugin/QuickLook.Plugin.TextViewer/QuickLook.Plugin.TextViewer.csproj

@@ -62,6 +62,7 @@
         <PackageReference Include="AvalonEdit" Version="6.3.1.120" />
         <PackageReference Include="UTF.Unknown" Version="2.5.1" />
         <Reference Include="WindowsBase" />
+        <Reference Include="System.ComponentModel.Composition" />
     </ItemGroup>
 
     <ItemGroup>

QuickLook.Plugin/QuickLook.Plugin.TextViewer/Syntax/Light/XML.xshd

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 
-<SyntaxDefinition name="XML" extensions=".xml;.xsl;.xslt;.xsd;.syn;.lang;.manifest;.config;.addin;.xshd;.wxs;.wxi;.wxl;.proj;.csproj;.vbproj;.resx;.user;.ilproj;.booproj;.build;.xfrm;.targets;.axaml;.xaml;.xpt;.xft;.map;.wsdl;.disco;.ascx;.atom;.bpmn;.cpt;.csl;.props">
+<SyntaxDefinition name="XML" extensions=".xml;.xsl;.xslt;.xsd;.syn;.lang;.manifest;.config;.addin;.xshd;.wxs;.wxi;.wxl;.proj;.csproj;.vbproj;.resx;.user;.ilproj;.booproj;.build;.xfrm;.targets;.axaml;.xaml;.xpt;.xft;.map;.wsdl;.disco;.ascx;.atom;.bpmn;.cpt;.csl;.props;">
     
     <Environment> 
         <Default color="Black" bgcolor="#FFFFFF"/>

QuickLook.Plugin/QuickLook.Plugin.TextViewer/TextViewerPanel.cs

@@ -17,35 +17,29 @@
 
 using ICSharpCode.AvalonEdit;
 using ICSharpCode.AvalonEdit.Document;
-using ICSharpCode.AvalonEdit.Highlighting;
 using ICSharpCode.AvalonEdit.Rendering;
 using ICSharpCode.AvalonEdit.Search;
 using QuickLook.Common.Helpers;
 using QuickLook.Common.Plugin;
+using QuickLook.Plugin.TextViewer.Detectors;
+using QuickLook.Plugin.TextViewer.Themes;
 using System;
 using System.IO;
-using System.Linq;
 using System.Reflection;
-using System.Text;
 using System.Threading.Tasks;
 using System.Windows.Controls;
 using System.Windows.Input;
 using System.Windows.Media;
 using System.Windows.Threading;
-using UtfUnknown;
 
 namespace QuickLook.Plugin.TextViewer;
 
-public class TextViewerPanel : TextEditor, IDisposable
+public partial class TextViewerPanel : TextEditor, IDisposable
 {
-    private readonly ContextObject _context;
     private bool _disposed;
-    private HighlightingManager highlightingManager = HighlightingManager.Instance;
 
-    public TextViewerPanel(string path, ContextObject context)
+    public TextViewerPanel()
     {
-        _context = context;
-
         FontSize = 14;
         ShowLineNumbers = true;
         WordWrap = true;
@@ -79,14 +73,6 @@ public class TextViewerPanel : TextEditor, IDisposable
         TextArea.TextView.ElementGenerators.Add(new TruncateLongLines());
 
         SearchPanel.Install(this);
-
-        LoadFileAsync(path);
-    }
-
-    public HighlightingManager HighlightingManager
-    {
-        get => highlightingManager;
-        set => highlightingManager = value;
     }
 
     public void Dispose()
@@ -146,7 +132,7 @@ public class TextViewerPanel : TextEditor, IDisposable
         }
     }
 
-    private void LoadFileAsync(string path)
+    public void LoadFileAsync(string path, ContextObject context)
     {
         _ = Task.Run(() =>
         {
@@ -173,15 +159,14 @@ public class TextViewerPanel : TextEditor, IDisposable
                 return;
 
             if (fileTooLong)
-                _context.Title += " (0 ~ 5MB)";
+                context.Title += " (0 ~ 5MB)";
 
             var bufferCopy = buffer.ToArray();
             buffer.Dispose();
 
-            var result = CharsetDetector.DetectFromBytes(bufferCopy);
-            var encoding = result.DoubleDetectFromResult(bufferCopy); // Fix issues
-
-            var doc = new TextDocument(encoding.GetString(bufferCopy));
+            var encoding = EncodingDetector.DetectFromBytes(bufferCopy);
+            var text = encoding.GetString(bufferCopy);
+            var doc = new TextDocument(text);
             doc.SetOwnerThread(Dispatcher.Thread);
 
             if (_disposed)
@@ -189,68 +174,30 @@ public class TextViewerPanel : TextEditor, IDisposable
 
             Dispatcher.BeginInvoke(() =>
             {
+                var extension = Path.GetExtension(path);
+                var highlighting = HighlightingThemeManager.GetHighlightingByExtensionOrDetector(extension, text);
+
                 Encoding = encoding;
                 SyntaxHighlighting = bufferCopy.Length > maxHighlightingLength
                     ? null
-                    : HighlightingManager?.GetDefinitionByExtension(Path.GetExtension(path));
+                    : highlighting.SyntaxHighlighting;
                 Document = doc;
 
-                _context.IsBusy = false;
+                if (highlighting.IsDark)
+                {
+                    Background = Brushes.Transparent;
+                    SetResourceReference(ForegroundProperty, "WindowTextForeground");
+                }
+                else
+                {
+                    // if os dark mode, but not AllowDarkTheme, make background light
+                    Background = OSThemeHelper.AppsUseDarkTheme()
+                        ? new SolidColorBrush(Color.FromArgb(175, 255, 255, 255))
+                        : Brushes.Transparent;
+                }
+
+                context.IsBusy = false;
             }, DispatcherPriority.Render);
         });
     }
 }
-
-file static class DetectionExtensions
-{
-    public static Encoding DoubleDetectFromResult(this DetectionResult result, byte[] buffer)
-    {
-        // Determine the highest confidence encoding, or fallback to ANSI
-        var encoding = result.Detected?.Encoding ?? Encoding.Default;
-
-        // When mixing encodings, one of the encodings may gain higher confidence
-        // In this case, we should return to encodings UTF8 / UTF32 / ANSI
-        // https://github.com/QL-Win/QuickLook/issues/769
-        if (encoding != Encoding.UTF8 && encoding != Encoding.UTF32 && encoding != Encoding.Default)
-        {
-            if (result.Details.Any(detail => detail.Encoding == Encoding.UTF8))
-            {
-                encoding = Encoding.UTF8;
-            }
-            else if (result.Details.Any(detail => detail.Encoding == Encoding.UTF32))
-            {
-                encoding = Encoding.UTF32;
-            }
-            else if (result.Details.Any(detail => detail.Encoding == Encoding.Default))
-            {
-                encoding = Encoding.Default;
-            }
-        }
-
-        // When the text is too short and lacks a BOM
-        // In this case, we should fallback to an encoding if it is not recognized as UTF8 / UTF32 / ANSI
-        // https://github.com/QL-Win/QuickLook/issues/471
-        // https://github.com/QL-Win/QuickLook/issues/600
-        // https://github.com/QL-Win/QuickLook/issues/954
-        if (buffer.Length <= 50)
-        {
-            if (encoding != Encoding.UTF8 && encoding != Encoding.UTF32 && encoding != Encoding.Default)
-            {
-                if (!Encoding.UTF8.GetString(buffer).Contains("\uFFFD"))
-                {
-                    encoding = Encoding.UTF8;
-                }
-                else if (!Encoding.UTF32.GetString(buffer).Contains("\uFFFD"))
-                {
-                    encoding = Encoding.UTF32;
-                }
-                else if (!Encoding.Default.GetString(buffer).Contains("\uFFFD"))
-                {
-                    encoding = Encoding.Default;
-                }
-            }
-        }
-
-        return encoding;
-    }
-}

QuickLook.Plugin/QuickLook.Plugin.TextViewer/Themes/HighlightingTheme.cs

@@ -0,0 +1,38 @@
+// Copyright © 2017-2025 QL-Win Contributors
+//
+// This file is part of QuickLook program.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+using ICSharpCode.AvalonEdit.Highlighting;
+
+namespace QuickLook.Plugin.TextViewer.Themes;
+
+public sealed class HighlightingTheme
+{
+    public static HighlightingTheme Default => new() // No case should be cached
+    {
+        HighlightingManager = HighlightingManager.Instance,
+    };
+
+    public string Theme { get; set; }
+
+    public bool IsDark => Theme == nameof(HighlightingThemeManager.Dark);
+
+    public HighlightingManager HighlightingManager { get; set; }
+
+    public IHighlightingDefinition SyntaxHighlighting { get; set; }
+
+    public string Extension { get; set; }
+}

QuickLook.Plugin/QuickLook.Plugin.TextViewer/Themes/HighlightingThemeManager.cs

@@ -0,0 +1,200 @@
+// Copyright © 2017-2025 QL-Win Contributors
+//
+// This file is part of QuickLook program.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+using ICSharpCode.AvalonEdit.Highlighting;
+using ICSharpCode.AvalonEdit.Highlighting.Xshd;
+using QuickLook.Common.Helpers;
+using QuickLook.Plugin.TextViewer.Detectors;
+using System;
+using System.Diagnostics;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using System.Xml;
+
+namespace QuickLook.Plugin.TextViewer.Themes;
+
+public class HighlightingThemeManager
+{
+    public static HighlightingManager Light { get; internal set; }
+
+    public static HighlightingManager Dark { get; internal set; }
+
+    public static void Initialize()
+    {
+        InitHighlightingManager();
+        AddHighlightingManager(Light, nameof(Light));
+        AddHighlightingManager(Dark, nameof(Dark));
+    }
+
+    public static HighlightingTheme GetHighlightingByExtensionOrDetector(string extension, string text = null)
+    {
+        if (Light is null || Dark is null) return HighlightingTheme.Default;
+
+        var highlightingTheme = GetDefinitionByExtension(nameof(Dark), extension);
+
+        if (highlightingTheme == null)
+        {
+            highlightingTheme = GetDefinitionByExtension(nameof(Light), extension);
+
+            if (highlightingTheme == null)
+            {
+                var useFormatDetector = SettingHelper.Get("UseFormatDetector", true, "QuickLook.Plugin.TextViewer");
+
+                if (useFormatDetector && FormatDetector.Detect(text)?.Extension is string detectExtension)
+                {
+                    highlightingTheme = GetDefinitionByExtension(nameof(Dark), detectExtension)
+                                     ?? GetDefinitionByExtension(nameof(Light), detectExtension);
+                }
+            }
+        }
+
+        // Unsupported highlighting
+        highlightingTheme ??= HighlightingTheme.Default;
+
+        var darkThemeAllowed = SettingHelper.Get("AllowDarkTheme", highlightingTheme.IsDark, "QuickLook.Plugin.TextViewer");
+        var isDark = darkThemeAllowed && OSThemeHelper.AppsUseDarkTheme();
+
+        // The current environment does not require dark mode so revert to light mode
+        if (!isDark && highlightingTheme.IsDark)
+        {
+            highlightingTheme.Theme = nameof(Light);
+            highlightingTheme.HighlightingManager = Light;
+            highlightingTheme.SyntaxHighlighting
+                // The extension that supports dark mode must support light mode also
+                = Light.GetDefinitionByExtension(highlightingTheme.Extension);
+        }
+
+        return highlightingTheme;
+    }
+
+    private static HighlightingTheme GetDefinitionByExtension(string theme, string extension)
+    {
+        var highlightingManager = theme == nameof(Dark) ? Dark : Light;
+        var def = highlightingManager.GetDefinitionByExtension(extension);
+
+        if (def != null)
+        {
+            return new HighlightingTheme()
+            {
+                Theme = theme,
+                HighlightingManager = highlightingManager,
+                SyntaxHighlighting = def,
+                Extension = extension,
+            };
+        }
+        return null;
+    }
+
+    private static void InitHighlightingManager()
+    {
+        Light = new HighlightingManager();
+        Dark = new HighlightingManager();
+
+        Assembly assembly = Assembly.GetExecutingAssembly();
+        string[] resourceNames = assembly.GetManifestResourceNames();
+
+        foreach (var resourceName in resourceNames.Where(name => name.Contains(".Syntax.")))
+        {
+            using Stream s = assembly.GetManifestResourceStream(resourceName);
+
+            if (s == null)
+                continue;
+
+            Debug.WriteLine(resourceName);
+
+            try
+            {
+                var hlm = resourceName.Contains(".Syntax.Dark.") ? Dark : Light;
+                var name = EmbeddedResource.GetFileNameWithoutExtension(resourceName);
+                using var reader = new XmlTextReader(s);
+                var xshd = HighlightingLoader.LoadXshd(reader);
+                var highlightingDefinition = HighlightingLoader.Load(xshd, hlm);
+                if (xshd.Extensions.Count > 0)
+                    hlm.RegisterHighlighting(name, [.. xshd.Extensions], highlightingDefinition);
+            }
+            catch (Exception e)
+            {
+                ProcessHelper.WriteLog(e.ToString());
+            }
+        }
+    }
+
+    private static void AddHighlightingManager(HighlightingManager hlm, string dirName)
+    {
+        var assemblyPath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
+        if (string.IsNullOrEmpty(assemblyPath))
+            return;
+
+        var syntaxPath = Path.Combine(assemblyPath, "Syntax", dirName);
+        if (!Directory.Exists(syntaxPath))
+            return;
+
+        foreach (var file in Directory.EnumerateFiles(syntaxPath, "*.xshd").OrderBy(f => f))
+        {
+            try
+            {
+                Debug.WriteLine(file);
+                var ext = Path.GetFileNameWithoutExtension(file);
+                using Stream s = File.OpenRead(Path.GetFullPath(file));
+                using var reader = new XmlTextReader(s);
+                var xshd = HighlightingLoader.LoadXshd(reader);
+                var highlightingDefinition = HighlightingLoader.Load(xshd, hlm);
+                if (xshd.Extensions.Count > 0)
+                    hlm.RegisterHighlighting(ext, [.. xshd.Extensions], highlightingDefinition);
+            }
+            catch (Exception e)
+            {
+                ProcessHelper.WriteLog(e.ToString());
+            }
+        }
+    }
+}
+
+file static class EmbeddedResource
+{
+    public static string GetFileNameWithoutExtension(string resourceName)
+    {
+        // Requires the embedded resource file name
+        // must have a file extension and have only one '.' character
+        int start = int.MinValue, end = int.MinValue;
+
+        for (int i = resourceName.Length - 1; i >= 0; i--)
+        {
+            if (resourceName[i] == '.')
+            {
+                if (end == int.MinValue)
+                {
+                    end = i;
+                    continue;
+                }
+
+                if (start == int.MinValue)
+                {
+                    start = i + 1; // Exinclude '.' character
+                    break;
+                }
+            }
+        }
+
+        if ((start != int.MinValue) && (end != int.MinValue))
+        {
+            return resourceName.Substring(start, end - start);
+        }
+        return resourceName;
+    }
+}