QuickLook/QuickLook.Plugin/QuickLook.Plugin.ChmViewer/ChmWebpagePanel.cs

// Copyright © 2017-2026 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 QuickLook.Common.Helpers;
using QuickLook.Plugin.HtmlViewer;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Reflection;

namespace QuickLook.Plugin.ChmViewer;

public class ChmWebpagePanel : WebpagePanel
{
    protected const string _resourcePrefix = "QuickLook.Plugin.ChmViewer.Resources.";
    protected internal static readonly Dictionary<string, byte[]> _resources = [];
    protected readonly byte[] _homePage;

    protected string _path;

    static ChmWebpagePanel()
    {
        InitializeResources();
    }

    public ChmWebpagePanel()
    {
        _homePage = ReadResource("/chm2html.html") ?? [];

        if (OSThemeHelper.AppsUseDarkTheme())
        {
            // Invoke using reflection: WebView2.CreationProperties.AdditionalBrowserArguments
            // This approach allows the library to avoid direct dependency on WebView2
            if (typeof(WebpagePanel).GetField("_webView", BindingFlags.NonPublic | BindingFlags.Instance) is FieldInfo fieldInfo)
            {
                object webView2 = fieldInfo.GetValue(this);

                if (webView2?.GetType().GetProperty("CreationProperties", BindingFlags.Public | BindingFlags.Instance) is PropertyInfo creationPropertiesProperty)
                {
                    object creationProperties = creationPropertiesProperty.GetValue(webView2);

                    if (creationProperties?.GetType().GetProperty("AdditionalBrowserArguments", BindingFlags.Public | BindingFlags.Instance) is PropertyInfo additionalBrowserArgumentsProperty)
                    {
                        string additionalBrowserArguments = (additionalBrowserArgumentsProperty.GetValue(creationProperties) as string) ?? string.Empty;
                        additionalBrowserArgumentsProperty.SetValue(creationProperties, additionalBrowserArguments + " --enable-features=WebContentsForceDark");
                    }
                }
            }
        }
    }

    private static void InitializeResources()
    {
        if (_resources.Any())
            return;

        var assembly = Assembly.GetExecutingAssembly();
        foreach (var resourceName in assembly.GetManifestResourceNames())
        {
            if (!resourceName.StartsWith(_resourcePrefix, StringComparison.Ordinal))
                continue;

            var relativePath = resourceName.Substring(_resourcePrefix.Length).Replace('\\', '/');
            if (string.IsNullOrEmpty(relativePath))
                continue;

            using var stream = assembly.GetManifestResourceStream(resourceName);
            if (stream == null)
                continue;

            using var memoryStream = new MemoryStream();
            stream.CopyTo(memoryStream);
            _resources[$"/{relativePath}"] = memoryStream.ToArray();
        }
    }

    public void PreviewCompiledHtmlHelp(string path)
    {
        _path = path;

        NavigateToUri(new Uri("http://quicklook/?plugin=1&chm=http://quicklook/.chm"));
    }

    protected override void WebView_WebResourceRequested(object sender, Microsoft.Web.WebView2.Core.CoreWebView2WebResourceRequestedEventArgs args)
    {
        Debug.WriteLine($"[{args.Request.Method}] {args.Request.Uri}");

        try
        {
            var requestedUri = new Uri(args.Request.Uri);

            if (requestedUri.Scheme == "http")
            {
                string absolutePath = Uri.UnescapeDataString(requestedUri.AbsolutePath);

                if (absolutePath == "/")
                {
                    var response = _webView.CoreWebView2.Environment.CreateWebResourceResponse(
                        new MemoryStream(_homePage), 200, "OK", MimeTypes.GetContentType(".html"));
                    args.Response = response;
                }
                else if (absolutePath == "/.chm")
                {
                    Stream stream = new FileStream(_path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite | FileShare.Delete);
                    var response = _webView.CoreWebView2.Environment.CreateWebResourceResponse(
                        stream, 200, "OK", MimeTypes.GetContentType(Path.GetExtension(".chm")));
                    args.Response = response;
                }
                else
                {
                    // It should not need to be dealt with anymore
                }
            }
        }
        catch (Exception e)
        {
            // We don't need to feel burdened by any exceptions
            Debug.WriteLine(e);
        }
    }

    private static bool ContainsKey(string key) => _resources.ContainsKey(key);

    private static Stream ReadStream(string key) => new MemoryStream(_resources[key]);

    private static byte[] ReadResource(string key) => _resources.TryGetValue(key, out var value) ? value : null;
}