fix(converters): fix HtmlProvider WebView2 thread crash and add MarkdownProvider for pure .NET conversions

src/Everything2Everything.Core/Converters/DocumentProvider.cs

@@ -17,17 +17,22 @@ namespace Everything2Everything.Core.Converters;
 //   txt ↔ md                                                     → trivial copy
 public sealed class DocumentProvider : IConverterProvider
 {
-    private static readonly string[] Inputs =
-        { ".html", ".htm", ".hwp", ".hwpx", ".docx", ".doc", ".md", ".markdown", ".txt" };
-
-    private static readonly string[] Outputs = { ".html", ".docx", ".md", ".txt" };
+    private static readonly string[] OfficeInputs = { ".docx", ".doc", ".hwp", ".hwpx" };
+    private static readonly string[] OfficeOutputs = { ".html", ".docx", ".md", ".txt" };
+    private static readonly string[] TextInputsToDocx = { ".html", ".htm", ".md", ".markdown", ".txt" };
 
     public ProviderCapability Capability { get; } = new(
         Id: "document",
-        DisplayName: "문서 텍스트 변환 (HTML/HWP/DOCX/MD/TXT)",
-        SupportedConversions: ProviderCapability.PairsFromMatrix(Inputs, Outputs),
+        DisplayName: "문서 텍스트 변환 (DOCX/HWP/오피스)",
+        SupportedConversions: ProviderCapability.PairsFromMatrix(OfficeInputs, OfficeOutputs)
+            .Concat(ProviderCapability.PairsFromMatrix(TextInputsToDocx, new[] { ".docx" }))
+            .Concat(new[]
+            {
+                new ConversionPair(".html", ".txt", LossClass.Recode),
+                new ConversionPair(".htm", ".txt", LossClass.Recode),
+            }).ToList(),
         Status: ProviderStatus.RequiresExternal,
-        Summary: "HTML·HWP·DOCX·Markdown·TXT 사이의 양방향 텍스트 변환 (LibreOffice + Markdig + ReverseMarkdown).",
+        Summary: "DOCX·HWP 문서를 HTML/DOCX/MD/TXT로 변환하거나 텍스트를 DOCX로 저장합니다 (LibreOffice 엔진).",
         ExternalDependencies: new[]
         {
             new ExternalDependency(

src/Everything2Everything.Core/Converters/HtmlProvider.cs

@@ -1,6 +1,7 @@
 using System.Text.Json;
 using System.Threading;
 using System.Windows;
+using System.Windows.Interop;
 using System.Windows.Threading;
 using Everything2Everything.Core.Providers;
 using ImageMagick;
@@ -165,7 +166,25 @@ public sealed class HtmlProvider : IConverterProvider
             try
             {
                 var dispatcher = Dispatcher.CurrentDispatcher;
-                _ = RunCaptureOnDispatcher(capture, dispatcher, sourcePath, options, progress, cancellationToken, tcs);
+                SynchronizationContext.SetSynchronizationContext(new DispatcherSynchronizationContext(dispatcher));
+
+                dispatcher.InvokeAsync(async () =>
+                {
+                    try
+                    {
+                        var bytes = await RunCaptureOnDispatcher(capture, sourcePath, options, progress, cancellationToken);
+                        tcs.TrySetResult(bytes);
+                    }
+                    catch (Exception ex)
+                    {
+                        tcs.TrySetException(ex);
+                    }
+                    finally
+                    {
+                        dispatcher.BeginInvokeShutdown(DispatcherPriority.Background);
+                    }
+                });
+
                 Dispatcher.Run();
             }
             catch (Exception ex)
@@ -181,16 +200,15 @@ public sealed class HtmlProvider : IConverterProvider
         return tcs.Task;
     }
 
-    private static async Task RunCaptureOnDispatcher(
+    private static async Task<byte[]> RunCaptureOnDispatcher(
         Func<CoreWebView2, IProgress<double>?, Task<byte[]>> capture,
-        Dispatcher dispatcher,
         string sourcePath,
         ConvertOptions options,
         IProgress<double>? progress,
-        CancellationToken cancellationToken,
-        TaskCompletionSource<byte[]> tcs)
+        CancellationToken cancellationToken)
     {
         CoreWebView2Controller? controller = null;
+        HwndSource? hwndSource = null;
         try
         {
             var userDataFolder = Path.Combine(
@@ -198,15 +216,23 @@ public sealed class HtmlProvider : IConverterProvider
                 "Everything2Everything", "WebView2");
             Directory.CreateDirectory(userDataFolder);
 
-            var env = await CoreWebView2Environment.CreateAsync(null, userDataFolder).ConfigureAwait(true);
+            var env = await CoreWebView2Environment.CreateAsync(null, userDataFolder);
             progress?.Report(0.15);
 
-            controller = await env.CreateCoreWebView2ControllerAsync(new IntPtr(-3)).ConfigureAwait(true);
-
             int width = options.HtmlRender.ViewportWidth > 0 ? options.HtmlRender.ViewportWidth : 1280;
             int height = options.HtmlRender.ViewportHeight ?? 720;
+
+            var parameters = new HwndSourceParameters("WebView2HiddenHost")
+            {
+                WindowStyle = 0x800000,
+                Width = width,
+                Height = height,
+            };
+            hwndSource = new HwndSource(parameters);
+
+            controller = await env.CreateCoreWebView2ControllerAsync(hwndSource.Handle);
             controller.Bounds = new System.Drawing.Rectangle(0, 0, width, height);
-            controller.IsVisible = false;
+            controller.IsVisible = true;
 
             var web = controller.CoreWebView2;
             progress?.Report(0.3);
@@ -217,36 +243,31 @@ public sealed class HtmlProvider : IConverterProvider
             {
                 web.NavigationCompleted -= navHandler!;
                 if (e.IsSuccess) navTcs.TrySetResult(true);
-                else navTcs.TrySetException(new InvalidOperationException(
-                    $"내비게이션 실패: {e.WebErrorStatus}"));
+                else navTcs.TrySetException(new InvalidOperationException($"내비게이션 실패: {e.WebErrorStatus}"));
             };
             web.NavigationCompleted += navHandler;
 
-            var fileUri = new Uri(sourcePath).AbsoluteUri;
+            var fileUri = new Uri(Path.GetFullPath(sourcePath)).AbsoluteUri;
             web.Navigate(fileUri);
 
             using (cancellationToken.Register(() => navTcs.TrySetCanceled()))
             {
-                await navTcs.Task.ConfigureAwait(true);
+                await navTcs.Task;
             }
             progress?.Report(0.5);
 
             if (options.HtmlRender.WaitMilliseconds > 0)
-                await Task.Delay(options.HtmlRender.WaitMilliseconds, cancellationToken).ConfigureAwait(true);
+                await Task.Delay(options.HtmlRender.WaitMilliseconds, cancellationToken);
 
             progress?.Report(0.65);
 
-            var bytes = await capture(web, progress).ConfigureAwait(true);
-            tcs.TrySetResult(bytes);
-        }
-        catch (Exception ex)
-        {
-            tcs.TrySetException(ex);
+            var bytes = await capture(web, progress);
+            return bytes;
         }
         finally
         {
             try { controller?.Close(); } catch { }
-            dispatcher.BeginInvokeShutdown(DispatcherPriority.Background);
+            try { hwndSource?.Dispose(); } catch { }
         }
     }
 

src/Everything2Everything.Core/Converters/MarkdownProvider.cs

@@ -0,0 +1,117 @@
+using System;
+using System.IO;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using Everything2Everything.Core.Providers;
+using Markdig;
+
+namespace Everything2Everything.Core.Converters;
+
+public sealed class MarkdownProvider : IConverterProvider
+{
+    private static readonly string[] MdInputs = { ".html", ".htm", ".md", ".markdown", ".txt" };
+
+    public ProviderCapability Capability { get; } = new(
+        Id: "markdown",
+        DisplayName: "마크다운 / HTML 텍스트",
+        SupportedConversions: new[]
+        {
+            new ConversionPair(".html", ".md", LossClass.Recode),
+            new ConversionPair(".htm", ".md", LossClass.Recode),
+            new ConversionPair(".md", ".html", LossClass.Recode),
+            new ConversionPair(".markdown", ".html", LossClass.Recode),
+            new ConversionPair(".md", ".txt", LossClass.Container),
+            new ConversionPair(".txt", ".md", LossClass.Container),
+            new ConversionPair(".txt", ".html", LossClass.Recode),
+        },
+        Status: ProviderStatus.Available,
+        Summary: "HTML·Markdown·TXT 사이의 순수 .NET 양방향 변환 (Markdig + ReverseMarkdown).",
+        ExternalDependencies: Array.Empty<ExternalDependency>(),
+        RoadmapNote: null);
+
+    public Task<ProviderAvailability> CheckAvailabilityAsync(CancellationToken cancellationToken = default)
+        => Task.FromResult(ProviderAvailability.Ready);
+
+    public async Task<ConvertResult> ConvertAsync(
+        string sourcePath,
+        string outputDirectory,
+        string outputExtension,
+        ConvertOptions options,
+        IProgress<double>? progress,
+        CancellationToken cancellationToken)
+    {
+        var inExt = Path.GetExtension(sourcePath).ToLowerInvariant();
+        var outExt = ConversionPair.Normalize(outputExtension);
+        var baseName = Path.GetFileNameWithoutExtension(sourcePath);
+        var outPath = OutputPathHelper.ResolveOutputPath(outputDirectory, baseName, null, outExt, options.OnCollision);
+
+        if (OutputPathHelper.ShouldSkip(outPath, options.OnCollision))
+            return ConvertResult.Skip(sourcePath, "기존 파일이 있어 건너뜁니다.");
+
+        progress?.Report(0.1);
+
+        try
+        {
+            if (inExt is ".html" or ".htm" && outExt == ".md")
+            {
+                await HtmlToMdAsync(sourcePath, outPath, cancellationToken).ConfigureAwait(false);
+            }
+            else if (inExt is ".md" or ".markdown" && outExt == ".html")
+            {
+                await MdToHtmlAsync(sourcePath, outPath, cancellationToken).ConfigureAwait(false);
+            }
+            else if (inExt == ".txt" && outExt == ".html")
+            {
+                await TxtToHtmlAsync(sourcePath, outPath, cancellationToken).ConfigureAwait(false);
+            }
+            else if ((inExt is ".md" or ".markdown" && outExt == ".txt") || (inExt == ".txt" && outExt == ".md"))
+            {
+                await Task.Run(() => File.Copy(sourcePath, outPath, overwrite: true), cancellationToken).ConfigureAwait(false);
+            }
+            else
+            {
+                return ConvertResult.Fail(sourcePath, $"지원하지 않는 변환: {inExt} → {outExt}");
+            }
+
+            progress?.Report(1.0);
+            return ConvertResult.Ok(sourcePath, new[] { outPath });
+        }
+        catch (OperationCanceledException) { throw; }
+        catch (Exception ex)
+        {
+            return ConvertResult.Fail(sourcePath, $"변환 실패: {ex.Message}", ex);
+        }
+    }
+
+    private static async Task MdToHtmlAsync(string mdPath, string htmlPath, CancellationToken ct)
+    {
+        var md = await File.ReadAllTextAsync(mdPath, Encoding.UTF8, ct).ConfigureAwait(false);
+        var pipeline = new MarkdownPipelineBuilder().UseAdvancedExtensions().Build();
+        var body = Markdown.ToHtml(md, pipeline);
+        var fullHtml = $"<!DOCTYPE html><html lang=\"ko\"><head><meta charset=\"utf-8\"><title>{Path.GetFileNameWithoutExtension(mdPath)}</title></head><body>{body}</body></html>";
+        await File.WriteAllTextAsync(htmlPath, fullHtml, Encoding.UTF8, ct).ConfigureAwait(false);
+    }
+
+    private static async Task HtmlToMdAsync(string htmlPath, string mdPath, CancellationToken ct)
+    {
+        var html = await File.ReadAllTextAsync(htmlPath, Encoding.UTF8, ct).ConfigureAwait(false);
+        var converter = new ReverseMarkdown.Converter(new ReverseMarkdown.Config
+        {
+            UnknownTags = ReverseMarkdown.Config.UnknownTagsOption.PassThrough,
+            GithubFlavored = true,
+            RemoveComments = true,
+            SmartHrefHandling = true,
+        });
+        var md = converter.Convert(html);
+        await File.WriteAllTextAsync(mdPath, md, Encoding.UTF8, ct).ConfigureAwait(false);
+    }
+
+    private static async Task TxtToHtmlAsync(string txtPath, string htmlPath, CancellationToken ct)
+    {
+        var txt = await File.ReadAllTextAsync(txtPath, Encoding.UTF8, ct).ConfigureAwait(false);
+        var encoded = System.Net.WebUtility.HtmlEncode(txt).Replace("\n", "<br/>\n");
+        var fullHtml = $"<!DOCTYPE html><html lang=\"ko\"><head><meta charset=\"utf-8\"><title>{Path.GetFileNameWithoutExtension(txtPath)}</title></head><body><pre style=\"font-family: 'Segoe UI', sans-serif; white-space: pre-wrap;\">{encoded}</pre></body></html>";
+        await File.WriteAllTextAsync(htmlPath, fullHtml, Encoding.UTF8, ct).ConfigureAwait(false);
+    }
+}

src/Everything2Everything.Tests/HtmlEndToEndAllOutputsTests.cs

@@ -0,0 +1,81 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using Everything2Everything.Core;
+using Everything2Everything.Core.Converters;
+using Everything2Everything.Core.Providers;
+using Xunit;
+using Xunit.Abstractions;
+
+namespace Everything2Everything.Tests;
+
+public class HtmlEndToEndAllOutputsTests
+{
+    private readonly ITestOutputHelper _output;
+
+    public HtmlEndToEndAllOutputsTests(ITestOutputHelper output)
+    {
+        _output = output;
+    }
+
+    private static string TempDir()
+    {
+        var d = Path.Combine(Path.GetTempPath(), "e2e_html_all_" + Guid.NewGuid().ToString("N"));
+        Directory.CreateDirectory(d);
+        return d;
+    }
+
+    [Theory]
+    [InlineData(".pdf")]
+    [InlineData(".png")]
+    [InlineData(".jpg")]
+    [InlineData(".webp")]
+    [InlineData(".avif")]
+    [InlineData(".bmp")]
+    [InlineData(".tiff")]
+    [InlineData(".gif")]
+    public async Task Html_To_ImagesAndPdf_Via_Engine_Succeeds(string targetExt)
+    {
+        var dir = TempDir();
+        var html = Path.Combine(dir, "sample.html");
+        await File.WriteAllTextAsync(html, "<html><body><h1 style='color:red;'>Test Page</h1><p>Paragraph content</p></body></html>");
+
+        var engine = Everything2EverythingBootstrap.CreateDefault();
+        var opt = new ConvertOptions
+        {
+            OutputLocation = OutputLocation.Custom,
+            CustomOutputDirectory = dir
+        };
+
+        using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(30));
+        var result = await engine.ConvertOneAsync(html, targetExt, opt, null, cts.Token);
+
+        _output.WriteLine($"Convert .html -> {targetExt}: Status={result.Status}, Msg={result.Message}");
+        Assert.Equal(ConvertStatus.Success, result.Status);
+        Assert.NotEmpty(result.OutputPaths);
+        Assert.True(File.Exists(result.OutputPaths[0]));
+        Assert.True(new FileInfo(result.OutputPaths[0]).Length > 0);
+    }
+
+    [Fact]
+    public async Task Html_To_Markdown_Via_Engine_TestsAvailability()
+    {
+        var dir = TempDir();
+        var html = Path.Combine(dir, "sample.html");
+        await File.WriteAllTextAsync(html, "<html><body><h1>Markdown Title</h1><p>Bold <b>text</b></p></body></html>");
+
+        var engine = Everything2EverythingBootstrap.CreateDefault();
+        var opt = new ConvertOptions
+        {
+            OutputLocation = OutputLocation.Custom,
+            CustomOutputDirectory = dir
+        };
+
+        using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(15));
+        var result = await engine.ConvertOneAsync(html, ".md", opt, null, cts.Token);
+
+        _output.WriteLine($"Convert .html -> .md: Status={result.Status}, Msg={result.Message}");
+    }
+}

src/Everything2Everything.Tests/HtmlProviderTests.cs

@@ -0,0 +1,60 @@
+using System;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using Everything2Everything.Core;
+using Everything2Everything.Core.Converters;
+using Everything2Everything.Core.Providers;
+using Xunit;
+
+namespace Everything2Everything.Tests;
+
+public class HtmlProviderTests
+{
+    private static string TempDir()
+    {
+        var d = Path.Combine(Path.GetTempPath(), "e2e_html_test_" + Guid.NewGuid().ToString("N"));
+        Directory.CreateDirectory(d);
+        return d;
+    }
+
+    [Fact]
+    public async Task HtmlProvider_ConvertAsync_HtmlToPdf_Succeeds()
+    {
+        var dir = TempDir();
+        var html = Path.Combine(dir, "test.html");
+        await File.WriteAllTextAsync(html, "<html><body><h1>Hello HTML Test</h1><p>Testing HTML to PDF</p></body></html>");
+
+        var provider = new HtmlProvider();
+        var availability = await provider.CheckAvailabilityAsync();
+        if (!availability.IsReady) return;
+
+        using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(30));
+        var result = await provider.ConvertAsync(html, dir, ".pdf", new ConvertOptions(), null, cts.Token);
+
+        Assert.Equal(ConvertStatus.Success, result.Status);
+        Assert.NotEmpty(result.OutputPaths);
+        Assert.True(File.Exists(result.OutputPaths[0]));
+        Assert.True(new FileInfo(result.OutputPaths[0]).Length > 0);
+    }
+
+    [Fact]
+    public async Task HtmlProvider_ConvertAsync_HtmlToPng_Succeeds()
+    {
+        var dir = TempDir();
+        var html = Path.Combine(dir, "test.html");
+        await File.WriteAllTextAsync(html, "<html><body><h1>Hello HTML Test</h1><p>Testing HTML to PNG</p></body></html>");
+
+        var provider = new HtmlProvider();
+        var availability = await provider.CheckAvailabilityAsync();
+        if (!availability.IsReady) return;
+
+        using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(30));
+        var result = await provider.ConvertAsync(html, dir, ".png", new ConvertOptions(), null, cts.Token);
+
+        Assert.Equal(ConvertStatus.Success, result.Status);
+        Assert.NotEmpty(result.OutputPaths);
+        Assert.True(File.Exists(result.OutputPaths[0]));
+        Assert.True(new FileInfo(result.OutputPaths[0]).Length > 0);
+    }
+}

src/Everything2Everything.Tests/MarkdownProviderTests.cs

@@ -0,0 +1,79 @@
+using System;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using Everything2Everything.Core;
+using Everything2Everything.Core.Converters;
+using Everything2Everything.Core.Providers;
+using Xunit;
+
+namespace Everything2Everything.Tests;
+
+public class MarkdownProviderTests
+{
+    private static string TempDir()
+    {
+        var d = Path.Combine(Path.GetTempPath(), "e2e_md_test_" + Guid.NewGuid().ToString("N"));
+        Directory.CreateDirectory(d);
+        return d;
+    }
+
+    [Fact]
+    public async Task MarkdownProvider_HtmlToMd_ConvertsProperly()
+    {
+        var dir = TempDir();
+        var html = Path.Combine(dir, "input.html");
+        await File.WriteAllTextAsync(html, "<h1>Title Here</h1><p>Paragraph with <strong>bold</strong> text</p>");
+
+        var provider = new MarkdownProvider();
+        var res = await provider.ConvertAsync(html, dir, ".md", new ConvertOptions(), null, CancellationToken.None);
+
+        Assert.Equal(ConvertStatus.Success, res.Status);
+        var content = await File.ReadAllTextAsync(res.OutputPaths[0]);
+        Assert.Contains("# Title Here", content);
+        Assert.Contains("**bold**", content);
+    }
+
+    [Fact]
+    public async Task MarkdownProvider_MdToHtml_ConvertsProperly()
+    {
+        var dir = TempDir();
+        var md = Path.Combine(dir, "input.md");
+        await File.WriteAllTextAsync(md, "# Hello Markdown\n\nThis is a *test*.");
+
+        var provider = new MarkdownProvider();
+        var res = await provider.ConvertAsync(md, dir, ".html", new ConvertOptions(), null, CancellationToken.None);
+
+        Assert.Equal(ConvertStatus.Success, res.Status);
+        var content = await File.ReadAllTextAsync(res.OutputPaths[0]);
+        Assert.Contains("Hello Markdown</h1>", content);
+        Assert.Contains("<em>test</em>", content);
+    }
+
+    [Fact]
+    public async Task MarkdownProvider_Availability_IsAlwaysReady()
+    {
+        var provider = new MarkdownProvider();
+        var avail = await provider.CheckAvailabilityAsync();
+        Assert.True(avail.IsReady);
+        Assert.Equal(ProviderStatus.Available, provider.Capability.Status);
+    }
+
+    [Fact]
+    public async Task Engine_HtmlToMd_RoutesToMarkdownProvider()
+    {
+        var dir = TempDir();
+        var html = Path.Combine(dir, "input.html");
+        await File.WriteAllTextAsync(html, "<h2>Section</h2><p>Content</p>");
+
+        var engine = Everything2EverythingBootstrap.CreateDefault();
+        var path = engine.Providers.Graph.FindBestPath(".html", ".md");
+        Assert.NotNull(path);
+        Assert.Single(path);
+        Assert.IsType<MarkdownProvider>(path![0].Provider);
+
+        var opt = new ConvertOptions { OutputLocation = OutputLocation.Custom, CustomOutputDirectory = dir };
+        var res = await engine.ConvertOneAsync(html, ".md", opt);
+        Assert.Equal(ConvertStatus.Success, res.Status);
+    }
+}

src/Everything2Everything.Tests/MatrixIntegrityTests.cs

@@ -0,0 +1,56 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Everything2Everything.Core;
+using Everything2Everything.Core.Providers;
+using Xunit;
+using Xunit.Abstractions;
+
+namespace Everything2Everything.Tests;
+
+public class MatrixIntegrityTests
+{
+    private readonly ITestOutputHelper _output;
+
+    public MatrixIntegrityTests(ITestOutputHelper output)
+    {
+        _output = output;
+    }
+
+    [Fact]
+    public void Audit_AllRegisteredProviders_AndPrintMatrix()
+    {
+        var engine = Everything2EverythingBootstrap.CreateDefault();
+        var providers = engine.Providers.All.ToList();
+
+        _output.WriteLine($"=== Total Registered Providers: {providers.Count} ===");
+        foreach (var p in providers)
+        {
+            var cap = p.Capability;
+            _output.WriteLine($"Provider [{cap.Id}] {cap.DisplayName} | Status: {cap.Status} | Pairs: {cap.SupportedConversions.Count}");
+            var missingDeps = cap.ExternalDependencies.Where(d => d.IsRequired).Select(d => d.Name).ToList();
+            if (missingDeps.Any())
+            {
+                _output.WriteLine($"   Required deps: {string.Join(", ", missingDeps)}");
+            }
+        }
+        Assert.NotEmpty(providers);
+    }
+
+    [Fact]
+    public void Audit_HtmlReachability_InGraph()
+    {
+        var engine = Everything2EverythingBootstrap.CreateDefault();
+        var outputs = engine.Providers.OutputsForInput(".html");
+        _output.WriteLine($"HTML Reachable Outputs ({outputs.Count}): {string.Join(", ", outputs)}");
+        
+        Assert.Contains(".pdf", outputs);
+        Assert.Contains(".png", outputs);
+        Assert.Contains(".jpg", outputs);
+        Assert.Contains(".webp", outputs);
+        Assert.Contains(".md", outputs);
+    }
+}