From a858860b3feb006bb054bcd1f293df88dd86eb45 Mon Sep 17 00:00:00 2001
From: lincube <lincube3@hotmail.com>
Date: Sat, 11 Jul 2026 16:11:41 +0900
Subject: [PATCH] feat.RSS

---
 .../RssReaderAirAppView.axaml                 |  64 ++
 .../RssReaderAirAppView.axaml.cs              | 318 +++++++++
 .../RssReaderServiceTests.cs                  |  87 +++
 .../Services/RssReader/RssReaderService.cs    | 665 ++++++++++++++++++
 .../RssReaderComponentEditor.cs               |  63 ++
 .../Views/Components/RssReaderWidget.axaml    |  76 ++
 .../Views/Components/RssReaderWidget.axaml.cs | 170 +++++
 7 files changed, 1443 insertions(+)
 create mode 100644 LanMountainDesktop.AirAppHost/RssReaderAirAppView.axaml
 create mode 100644 LanMountainDesktop.AirAppHost/RssReaderAirAppView.axaml.cs
 create mode 100644 LanMountainDesktop.Tests/RssReaderServiceTests.cs
 create mode 100644 LanMountainDesktop/Services/RssReader/RssReaderService.cs
 create mode 100644 LanMountainDesktop/Views/ComponentEditors/RssReaderComponentEditor.cs
 create mode 100644 LanMountainDesktop/Views/Components/RssReaderWidget.axaml
 create mode 100644 LanMountainDesktop/Views/Components/RssReaderWidget.axaml.cs

diff --git a/LanMountainDesktop.AirAppHost/RssReaderAirAppView.axaml b/LanMountainDesktop.AirAppHost/RssReaderAirAppView.axaml
new file mode 100644
index 0000000..2be9639
--- /dev/null
+++ b/LanMountainDesktop.AirAppHost/RssReaderAirAppView.axaml
@@ -0,0 +1,64 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             x:Class="LanMountainDesktop.AirAppHost.RssReaderAirAppView">
+  <Grid ColumnDefinitions="250,*" Background="{DynamicResource ApplicationPageBackgroundThemeBrush}">
+    <Border Grid.Column="0" BorderBrush="{DynamicResource CardStrokeColorDefaultBrush}" BorderThickness="0,0,1,0" Padding="14">
+      <Grid RowDefinitions="Auto,Auto,*,Auto" RowSpacing="12">
+        <StackPanel Orientation="Horizontal" Spacing="8">
+          <Button x:Name="AddButton" Content="Add source"/>
+          <Button x:Name="RefreshButton" Content="Refresh"/>
+        </StackPanel>
+        <StackPanel Grid.Row="1" Spacing="4">
+          <Button x:Name="AllButton" HorizontalContentAlignment="Left" Content="All articles"/>
+          <Button x:Name="UnreadButton" HorizontalContentAlignment="Left" Content="Unread"/>
+          <Button x:Name="FavoritesButton" HorizontalContentAlignment="Left" Content="Favorites"/>
+        </StackPanel>
+        <Grid Grid.Row="2" RowDefinitions="*,Auto" RowSpacing="6">
+          <ListBox x:Name="SourcesList"/>
+          <StackPanel Grid.Row="1" Orientation="Horizontal" Spacing="6">
+            <Button x:Name="EditSourceButton" Content="Edit" IsEnabled="False"/>
+            <Button x:Name="DeleteSourceButton" Content="Delete" IsEnabled="False"/>
+          </StackPanel>
+        </Grid>
+        <StackPanel Grid.Row="3" Spacing="6">
+          <Button x:Name="ImportButton" Content="Import OPML" HorizontalContentAlignment="Left"/>
+          <Button x:Name="ExportButton" Content="Export OPML" HorizontalContentAlignment="Left"/>
+          <Button x:Name="SettingsButton" Content="Settings" HorizontalContentAlignment="Left"/>
+          <TextBlock x:Name="StatusText" FontSize="11" Opacity="0.65" TextWrapping="Wrap"/>
+        </StackPanel>
+      </Grid>
+    </Border>
+    <Grid Grid.Column="1" ColumnDefinitions="330,*">
+      <Border BorderBrush="{DynamicResource CardStrokeColorDefaultBrush}" BorderThickness="0,0,1,0" Padding="12">
+        <Grid RowDefinitions="Auto,*" RowSpacing="10">
+          <Grid ColumnDefinitions="*,Auto">
+            <TextBlock x:Name="ListTitle" Text="All articles" FontSize="20" FontWeight="SemiBold"/>
+            <Button x:Name="MarkAllReadButton" Grid.Column="1" Content="Mark all read"/>
+          </Grid>
+          <ListBox x:Name="EntriesList" Grid.Row="1">
+            <ListBox.ItemTemplate>
+              <DataTemplate x:CompileBindings="False">
+                <StackPanel Margin="4,8" Spacing="4">
+                  <TextBlock Text="{Binding DisplayTitle}" FontWeight="{Binding Weight}" TextWrapping="Wrap" MaxLines="3"/>
+                  <TextBlock Text="{Binding Metadata}" FontSize="11" Opacity="0.6"/>
+                </StackPanel>
+              </DataTemplate>
+            </ListBox.ItemTemplate>
+          </ListBox>
+        </Grid>
+      </Border>
+      <Grid Grid.Column="1" Margin="22" RowDefinitions="Auto,Auto,*,Auto" RowSpacing="12">
+        <TextBlock x:Name="ArticleTitle" Text="Select an article" FontSize="26" FontWeight="SemiBold" TextWrapping="Wrap"/>
+        <TextBlock x:Name="ArticleMeta" Grid.Row="1" Opacity="0.6"/>
+        <ScrollViewer x:Name="ArticleTextScroller" Grid.Row="2">
+          <TextBlock x:Name="ArticleBody" Text="Your RSS articles will appear here." TextWrapping="Wrap" FontSize="15" LineHeight="24"/>
+        </ScrollViewer>
+        <Grid x:Name="ArticleHtmlHost" Grid.Row="2" IsVisible="False"/>
+        <StackPanel Grid.Row="3" Orientation="Horizontal" Spacing="8">
+          <Button x:Name="FavoriteButton" Content="☆ Favorite" IsEnabled="False"/>
+          <Button x:Name="OpenOriginalButton" Content="Open original" IsEnabled="False"/>
+        </StackPanel>
+      </Grid>
+    </Grid>
+  </Grid>
+</UserControl>
diff --git a/LanMountainDesktop.AirAppHost/RssReaderAirAppView.axaml.cs b/LanMountainDesktop.AirAppHost/RssReaderAirAppView.axaml.cs
new file mode 100644
index 0000000..df93215
--- /dev/null
+++ b/LanMountainDesktop.AirAppHost/RssReaderAirAppView.axaml.cs
@@ -0,0 +1,318 @@
+using System.Diagnostics;
+using Avalonia.Controls;
+using Avalonia.Interactivity;
+using Avalonia.Layout;
+using Avalonia.Media;
+using Avalonia.Platform.Storage;
+using Avalonia.Threading;
+using LanMountainDesktop.Services;
+using LanMountainDesktop.Services.RssReader;
+using LanMountainDesktop.Services.Settings;
+
+namespace LanMountainDesktop.AirAppHost;
+
+public sealed partial class RssReaderAirAppView : UserControl, IDisposable
+{
+    private readonly AirAppLaunchOptions _options;
+    private readonly RssReaderService _service = new();
+    private readonly LocalizationService _localization = new();
+    private readonly string _languageCode;
+    private string? _sourceId;
+    private bool _unreadOnly;
+    private bool _favoritesOnly;
+    private RssEntry? _selectedEntry;
+    private string? _lastHandledTargetEntryId;
+    private readonly DispatcherTimer _refreshTimer = new();
+    private NativeWebView? _articleWebView;
+
+    public RssReaderAirAppView() : this(AirAppLaunchOptions.Parse([])) { }
+
+    public RssReaderAirAppView(AirAppLaunchOptions options)
+    {
+        _options = options;
+        try
+        {
+            _languageCode = _localization.NormalizeLanguageCode(new AppSettingsService().Load().LanguageCode);
+        }
+        catch
+        {
+            _languageCode = "zh-CN";
+        }
+        InitializeComponent();
+        ApplyLocalization();
+        AddButton.Click += OnAdd;
+        RefreshButton.Click += OnRefresh;
+        AllButton.Click += (_, _) => SetFilter(null, false, false, L("rss.all_articles", "All articles"));
+        UnreadButton.Click += (_, _) => SetFilter(null, true, false, L("rss.unread", "Unread"));
+        FavoritesButton.Click += (_, _) => SetFilter(null, false, true, L("rss.favorites", "Favorites"));
+        SourcesList.SelectionChanged += OnSourceSelected;
+        EditSourceButton.Click += OnEditSource;
+        DeleteSourceButton.Click += OnDeleteSource;
+        EntriesList.SelectionChanged += OnEntrySelected;
+        MarkAllReadButton.Click += OnMarkAllRead;
+        FavoriteButton.Click += OnFavorite;
+        OpenOriginalButton.Click += OnOpenOriginal;
+        ImportButton.Click += OnImport;
+        ExportButton.Click += OnExport;
+        SettingsButton.Click += OnSettings;
+        _service.Changed += OnChanged;
+        _refreshTimer.Tick += async (_, _) => await RefreshAsync(force: false);
+        DetachedFromVisualTree += (_, _) => Dispose();
+        Reload();
+        ConfigureRefreshTimer();
+        _ = RefreshAsync(force: true);
+    }
+
+    public void Dispose()
+    {
+        _service.Changed -= OnChanged;
+        _refreshTimer.Stop();
+        if (_articleWebView is not null)
+        {
+            ArticleHtmlHost.Children.Remove(_articleWebView);
+            _articleWebView = null;
+        }
+        _service.Dispose();
+    }
+
+    private void OnChanged(object? sender, EventArgs e) => Dispatcher.UIThread.Post(Reload);
+
+    private void Reload()
+    {
+        var selectedSource = _sourceId;
+        SourcesList.ItemsSource = _service.GetSources().Select(source => new SourceItem(source)).ToArray();
+        var entries = _service.GetEntries(_sourceId, _unreadOnly, _favoritesOnly, 500);
+        EntriesList.ItemsSource = entries.Select(entry => new EntryItem(entry)).ToArray();
+        var targetEntryId = _options.TargetEntryId ?? _service.GetPendingEntryId();
+        if (!string.IsNullOrWhiteSpace(targetEntryId) && targetEntryId != _lastHandledTargetEntryId)
+        {
+            var target = entries.FirstOrDefault(entry => entry.Id == targetEntryId) ?? _service.GetEntry(targetEntryId);
+            if (target is not null) { _lastHandledTargetEntryId = targetEntryId; ShowEntry(target); }
+        }
+        StatusText.Text = string.Format(L("rss.status_counts", "{0} articles · {1} sources"), entries.Count, _service.GetSources().Count);
+    }
+
+    private void SetFilter(string? sourceId, bool unread, bool favorites, string title)
+    {
+        _sourceId = sourceId; _unreadOnly = unread; _favoritesOnly = favorites; ListTitle.Text = title; Reload();
+    }
+
+    private void OnSourceSelected(object? sender, SelectionChangedEventArgs e)
+    {
+        var hasSource = SourcesList.SelectedItem is SourceItem;
+        EditSourceButton.IsEnabled = hasSource;
+        DeleteSourceButton.IsEnabled = hasSource;
+        if (SourcesList.SelectedItem is SourceItem item) SetFilter(item.Source.Id, false, false, item.Source.Title);
+    }
+
+    private async void OnEditSource(object? sender, RoutedEventArgs e)
+    {
+        if (SourcesList.SelectedItem is not SourceItem item) return;
+        var owner = TopLevel.GetTopLevel(this) as Window; if (owner is null) return;
+        var title = new TextBox { Text = item.Source.Title, Width = 390 };
+        var folder = new TextBox { Text = item.Source.Folder, Width = 390 };
+        var enabled = new CheckBox { Content = L("rss.enabled", "Enabled"), IsChecked = item.Source.IsEnabled };
+        var interval = new NumericUpDown { Minimum = 15, Maximum = 1440, Value = item.Source.RefreshIntervalMinutes ?? 30 };
+        var save = new Button { Content = L("rss.save", "Save"), HorizontalAlignment = HorizontalAlignment.Right };
+        var dialog = new Window { Title = L("rss.edit_source", "Edit RSS source"), Width = 460, Height = 360, CanResize = false };
+        save.Click += (_, _) =>
+        {
+            _service.UpdateSource(item.Source.Id, title.Text ?? item.Source.Title, folder.Text, enabled.IsChecked == true, (int)(interval.Value ?? 30));
+            dialog.Close();
+        };
+        dialog.Content = new StackPanel { Margin = new Avalonia.Thickness(24), Spacing = 10, Children = { new TextBlock { Text = L("rss.name", "Name") }, title, new TextBlock { Text = L("rss.folder", "Folder") }, folder, enabled, new TextBlock { Text = L("rss.refresh_interval_minutes", "Refresh interval (minutes)") }, interval, save } };
+        await dialog.ShowDialog(owner);
+    }
+
+    private async void OnDeleteSource(object? sender, RoutedEventArgs e)
+    {
+        if (SourcesList.SelectedItem is not SourceItem item) return;
+        var owner = TopLevel.GetTopLevel(this) as Window; if (owner is null) return;
+        var preserve = new CheckBox { Content = L("rss.keep_favorites", "Keep favorited articles"), IsChecked = true };
+        var delete = new Button { Content = L("rss.delete", "Delete"), HorizontalAlignment = HorizontalAlignment.Right };
+        var cancel = new Button { Content = L("rss.cancel", "Cancel") };
+        var dialog = new Window { Title = L("rss.delete_source", "Delete RSS source"), Width = 420, Height = 220, CanResize = false };
+        delete.Click += (_, _) => { _service.DeleteSource(item.Source.Id, preserve.IsChecked == true); _sourceId = null; dialog.Close(); };
+        cancel.Click += (_, _) => dialog.Close();
+        dialog.Content = new StackPanel { Margin = new Avalonia.Thickness(24), Spacing = 14, Children = { new TextBlock { Text = string.Format(L("rss.delete_source_confirm", "Delete {0}?"), item.Source.Title), FontSize = 18, TextWrapping = TextWrapping.Wrap }, preserve, new StackPanel { Orientation = Orientation.Horizontal, Spacing = 8, HorizontalAlignment = HorizontalAlignment.Right, Children = { cancel, delete } } } };
+        await dialog.ShowDialog(owner);
+    }
+
+    private void OnEntrySelected(object? sender, SelectionChangedEventArgs e)
+    {
+        if (EntriesList.SelectedItem is EntryItem item) ShowEntry(item.Entry);
+    }
+
+    private void ShowEntry(RssEntry entry)
+    {
+        if (!entry.IsRead) _service.MarkRead(entry.Id);
+        _selectedEntry = entry with { IsRead = true };
+        ArticleTitle.Text = entry.Title;
+        ArticleMeta.Text = $"{entry.SourceTitle} · {entry.PublishedAt.ToLocalTime():g}{(string.IsNullOrWhiteSpace(entry.Author) ? string.Empty : " · " + entry.Author)}";
+        var html = string.IsNullOrWhiteSpace(entry.Content) ? entry.Summary : entry.Content;
+        ShowArticleContent(html);
+        FavoriteButton.IsEnabled = true;
+        FavoriteButton.Content = entry.IsFavorite ? $"★ {L("rss.favorited", "Favorited")}" : $"☆ {L("rss.favorite", "Favorite")}";
+        OpenOriginalButton.IsEnabled = !string.IsNullOrWhiteSpace(entry.Link);
+    }
+
+    private async void OnRefresh(object? sender, RoutedEventArgs e) => await RefreshAsync(force: true);
+    private async Task RefreshAsync(bool force)
+    {
+        RefreshButton.IsEnabled = false; StatusText.Text = L("rss.refreshing", "Refreshing…");
+        try { await _service.RefreshAllAsync(force); StatusText.Text = L("rss.updated", "Updated"); }
+        catch (Exception ex) { StatusText.Text = $"{L("rss.refresh_failed", "Refresh failed")}: {ex.Message}"; }
+        finally { RefreshButton.IsEnabled = true; Reload(); }
+    }
+
+    private void OnMarkAllRead(object? sender, RoutedEventArgs e) => _service.MarkAllRead(_sourceId);
+    private void OnFavorite(object? sender, RoutedEventArgs e)
+    {
+        if (_selectedEntry is null) return;
+        var favorite = !_selectedEntry.IsFavorite;
+        _service.SetFavorite(_selectedEntry.Id, favorite);
+        ShowEntry(_selectedEntry with { IsFavorite = favorite });
+    }
+
+    private void OnOpenOriginal(object? sender, RoutedEventArgs e)
+    {
+        if (!Uri.TryCreate(_selectedEntry?.Link, UriKind.Absolute, out var uri)) return;
+        Process.Start(new ProcessStartInfo(uri.AbsoluteUri) { UseShellExecute = true });
+    }
+
+    private void ShowArticleContent(string html)
+    {
+        var settings = _service.GetSettings();
+        var sanitized = RssReaderService.SanitizeHtml(html, settings.LoadRemoteImages);
+        ArticleBody.Text = RssReaderService.ToPlainText(sanitized);
+        try
+        {
+            var availability = WebView2RuntimeProbe.GetAvailability();
+            if (!availability.IsAvailable || string.IsNullOrWhiteSpace(sanitized))
+            {
+                ArticleHtmlHost.IsVisible = false;
+                ArticleTextScroller.IsVisible = true;
+                return;
+            }
+
+            _articleWebView ??= CreateArticleWebView();
+            var imagePolicy = settings.LoadRemoteImages ? "https: http: data:" : "data:";
+            var document = $$"""
+                <!doctype html><html><head><meta charset="utf-8">
+                <meta http-equiv="Content-Security-Policy" content="default-src 'none'; img-src {{imagePolicy}}; style-src 'unsafe-inline'">
+                <style>body{font-family:system-ui,sans-serif;margin:24px;color:#202124;line-height:1.65;font-size:16px}img{max-width:100%;height:auto}a{color:#0067c0}pre{white-space:pre-wrap}</style>
+                </head><body>{{sanitized}}</body></html>
+                """;
+            var encoded = Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes(document));
+            _articleWebView.Navigate(new Uri($"data:text/html;base64,{encoded}"));
+            ArticleTextScroller.IsVisible = false;
+            ArticleHtmlHost.IsVisible = true;
+        }
+        catch
+        {
+            ArticleHtmlHost.IsVisible = false;
+            ArticleTextScroller.IsVisible = true;
+        }
+    }
+
+    private NativeWebView CreateArticleWebView()
+    {
+        var webView = new NativeWebView();
+        ArticleHtmlHost.Children.Add(webView);
+        return webView;
+    }
+
+    private async void OnAdd(object? sender, RoutedEventArgs e)
+    {
+        var owner = TopLevel.GetTopLevel(this) as Window;
+        if (owner is null) return;
+        var url = new TextBox { PlaceholderText = "https://example.com/feed.xml", Width = 430 };
+        var title = new TextBox { PlaceholderText = L("rss.optional_name", "Optional custom name"), Width = 430 };
+        var folder = new TextBox { PlaceholderText = L("rss.optional_folder", "Optional folder"), Width = 430 };
+        var message = new TextBlock { TextWrapping = TextWrapping.Wrap };
+        var add = new Button { Content = L("rss.probe_add", "Probe and add"), HorizontalAlignment = HorizontalAlignment.Right };
+        var dialog = new Window { Title = L("rss.add_source", "Add RSS source"), Width = 500, Height = 330, CanResize = false };
+        add.Click += async (_, _) =>
+        {
+            add.IsEnabled = false; message.Text = L("rss.checking_feed", "Checking feed…");
+            try
+            {
+                var probe = await _service.ProbeAsync(url.Text ?? string.Empty);
+                message.Text = $"{probe.Title} · {probe.Format}";
+                await _service.AddSourceAsync(url.Text ?? string.Empty, title.Text, folder.Text);
+                dialog.Close();
+            }
+            catch (Exception ex) { message.Text = ex.Message; add.IsEnabled = true; }
+        };
+        dialog.Content = new StackPanel { Margin = new Avalonia.Thickness(24), Spacing = 12, Children = { new TextBlock { Text = L("rss.feed_url", "Feed URL") }, url, new TextBlock { Text = L("rss.name", "Name") }, title, new TextBlock { Text = L("rss.folder", "Folder") }, folder, message, add } };
+        await dialog.ShowDialog(owner);
+    }
+
+    private async void OnImport(object? sender, RoutedEventArgs e)
+    {
+        var top = TopLevel.GetTopLevel(this); if (top is null) return;
+        var files = await top.StorageProvider.OpenFilePickerAsync(new FilePickerOpenOptions { Title = L("rss.import_opml", "Import OPML"), AllowMultiple = false, FileTypeFilter = [new FilePickerFileType("OPML") { Patterns = ["*.opml", "*.xml"] }] });
+        var path = files.FirstOrDefault()?.TryGetLocalPath(); if (path is null) return;
+        var result = await _service.ImportOpmlAsync(path); StatusText.Text = string.Format(L("rss.import_result", "Imported {0}, skipped {1}, failed {2}."), result.Added, result.Skipped, result.Failed);
+    }
+
+    private async void OnExport(object? sender, RoutedEventArgs e)
+    {
+        var top = TopLevel.GetTopLevel(this); if (top is null) return;
+        var file = await top.StorageProvider.SaveFilePickerAsync(new FilePickerSaveOptions { Title = L("rss.export_opml", "Export OPML"), SuggestedFileName = "subscriptions.opml", FileTypeChoices = [new FilePickerFileType("OPML") { Patterns = ["*.opml"] }] });
+        var path = file?.TryGetLocalPath(); if (path is null) return; _service.ExportOpml(path); StatusText.Text = L("rss.exported", "OPML exported.");
+    }
+
+    private async void OnSettings(object? sender, RoutedEventArgs e)
+    {
+        var owner = TopLevel.GetTopLevel(this) as Window; if (owner is null) return;
+        var settings = _service.GetSettings();
+        var interval = new ComboBox { ItemsSource = new[] { new Choice(15, string.Format(L("rss.minutes", "{0} minutes"), 15)), new Choice(30, string.Format(L("rss.minutes", "{0} minutes"), 30)), new Choice(60, string.Format(L("rss.minutes", "{0} minutes"), 60)), new Choice(0,L("rss.manual_only", "Manual only")) }, SelectedIndex = settings.RefreshIntervalMinutes switch { 15 => 0, 60 => 2, 0 => 3, _ => 1 } };
+        var images = new CheckBox { Content = L("rss.load_remote_images", "Load remote images"), IsChecked = settings.LoadRemoteImages };
+        var save = new Button { Content = L("rss.save", "Save"), HorizontalAlignment = HorizontalAlignment.Right };
+        var dialog = new Window { Title = L("rss.settings", "RSS settings"), Width = 420, Height = 240, CanResize = false };
+        save.Click += (_, _) => { var value = (interval.SelectedItem as Choice)?.Value ?? 30; _service.SaveSettings(settings with { RefreshIntervalMinutes = value, LoadRemoteImages = images.IsChecked == true }); ConfigureRefreshTimer(); dialog.Close(); };
+        dialog.Content = new StackPanel { Margin = new Avalonia.Thickness(24), Spacing = 14, Children = { new TextBlock { Text = L("rss.refresh_interval", "Refresh interval") }, interval, images, save } };
+        await dialog.ShowDialog(owner);
+    }
+
+    private sealed record SourceItem(RssSource Source) { public override string ToString() => string.IsNullOrWhiteSpace(Source.Folder) ? Source.Title : $"{Source.Folder} / {Source.Title}"; }
+
+    private void ConfigureRefreshTimer()
+    {
+        var minutes = _service.GetSettings().RefreshIntervalMinutes;
+        _refreshTimer.Stop();
+        if (minutes <= 0) return;
+        _refreshTimer.Interval = TimeSpan.FromMinutes(minutes);
+        _refreshTimer.Start();
+    }
+
+    private void ApplyLocalization()
+    {
+        AddButton.Content = L("rss.add_source", "Add source");
+        RefreshButton.Content = L("rss.refresh", "Refresh");
+        AllButton.Content = L("rss.all_articles", "All articles");
+        UnreadButton.Content = L("rss.unread", "Unread");
+        FavoritesButton.Content = L("rss.favorites", "Favorites");
+        EditSourceButton.Content = L("rss.edit", "Edit");
+        DeleteSourceButton.Content = L("rss.delete", "Delete");
+        ImportButton.Content = L("rss.import_opml", "Import OPML");
+        ExportButton.Content = L("rss.export_opml", "Export OPML");
+        SettingsButton.Content = L("rss.settings", "Settings");
+        ListTitle.Text = L("rss.all_articles", "All articles");
+        MarkAllReadButton.Content = L("rss.mark_all_read", "Mark all read");
+        ArticleTitle.Text = L("rss.select_article", "Select an article");
+        ArticleBody.Text = L("rss.article_placeholder", "Your RSS articles will appear here.");
+        FavoriteButton.Content = $"☆ {L("rss.favorite", "Favorite")}";
+        OpenOriginalButton.Content = L("rss.open_original", "Open original");
+    }
+
+    private string L(string key, string fallback) => _localization.GetString(_languageCode, key, fallback);
+    private sealed record EntryItem(RssEntry Entry)
+    {
+        public string DisplayTitle => (Entry.IsRead ? string.Empty : "● ") + Entry.Title;
+        public FontWeight Weight => Entry.IsRead ? FontWeight.Normal : FontWeight.SemiBold;
+        public string Metadata => $"{Entry.SourceTitle} · {Entry.PublishedAt.ToLocalTime():g}{(Entry.IsFavorite ? " · ★" : string.Empty)}";
+    }
+    private sealed record Choice(int Value, string Label) { public override string ToString() => Label; }
+}
diff --git a/LanMountainDesktop.Tests/RssReaderServiceTests.cs b/LanMountainDesktop.Tests/RssReaderServiceTests.cs
new file mode 100644
index 0000000..7452f76
--- /dev/null
+++ b/LanMountainDesktop.Tests/RssReaderServiceTests.cs
@@ -0,0 +1,87 @@
+using System.Text;
+using System.Xml;
+using System.Xml.Linq;
+using LanMountainDesktop.ComponentSystem;
+using LanMountainDesktop.Services.RssReader;
+using Microsoft.Data.Sqlite;
+using Xunit;
+
+namespace LanMountainDesktop.Tests;
+
+public sealed class RssReaderServiceTests : IDisposable
+{
+    private readonly string _root = Path.Combine(Path.GetTempPath(), "LanMountainDesktop.RssTests", Guid.NewGuid().ToString("N"));
+
+    [Fact]
+    public void ComponentDefinition_UsesInfoCategoryAndEightByFourMinimum()
+    {
+        var registry = ComponentRegistry.CreateDefault();
+        Assert.True(registry.TryGetDefinition(BuiltInComponentIds.DesktopRssReader, out var definition));
+        Assert.Equal("Info", definition.Category);
+        Assert.Equal(8, definition.MinWidthCells);
+        Assert.Equal(4, definition.MinHeightCells);
+        Assert.Equal(DesktopComponentResizeMode.Free, definition.ResizeMode);
+    }
+
+    [Theory]
+    [InlineData("HTTPS://Example.COM:443/feed/#fragment", "https://example.com/feed")]
+    [InlineData("http://Example.com:80/rss", "http://example.com/rss")]
+    public void NormalizeFeedUrl_CanonicalizesAddress(string input, string expected)
+    {
+        Assert.Equal(expected, RssReaderService.NormalizeFeedUrl(input));
+    }
+
+    [Fact]
+    public void ParseProbe_ReadsRssAndAtom()
+    {
+        var rss = Encoding.UTF8.GetBytes("""<?xml version="1.0"?><rss version="2.0"><channel><title>News</title><link>https://example.com</link><description>Test</description><item><title>One</title><guid>1</guid></item></channel></rss>""");
+        var atom = Encoding.UTF8.GetBytes("""<?xml version="1.0"?><feed xmlns="http://www.w3.org/2005/Atom"><title>Atom News</title><id>x</id><updated>2026-01-01T00:00:00Z</updated><entry><title>One</title><id>1</id><updated>2026-01-01T00:00:00Z</updated></entry></feed>""");
+
+        Assert.Equal("News", RssReaderService.ParseProbe(rss, "https://example.com/rss").Title);
+        Assert.Equal("Atom", RssReaderService.ParseProbe(atom, "https://example.com/atom").Format);
+    }
+
+    [Fact]
+    public void ParseProbe_RejectsDtd()
+    {
+        var xml = Encoding.UTF8.GetBytes("""<?xml version="1.0"?><!DOCTYPE rss [<!ENTITY xxe SYSTEM "file:///etc/passwd">]><rss version="2.0"><channel><title>&xxe;</title><description>x</description><link>https://example.com</link></channel></rss>""");
+        Assert.ThrowsAny<XmlException>(() => RssReaderService.ParseProbe(xml, "https://example.com/rss"));
+    }
+
+    [Fact]
+    public void SanitizeHtml_RemovesExecutableContentAndRemoteImages()
+    {
+        var sanitized = RssReaderService.SanitizeHtml("<script>alert(1)</script><p onclick=\"x()\">Hello</p><img src=\"https://x/img.png\"><a href=\"javascript:x()\">bad</a>", false);
+        Assert.DoesNotContain("script", sanitized, StringComparison.OrdinalIgnoreCase);
+        Assert.DoesNotContain("onclick", sanitized, StringComparison.OrdinalIgnoreCase);
+        Assert.DoesNotContain("<img", sanitized, StringComparison.OrdinalIgnoreCase);
+        Assert.DoesNotContain("javascript:", sanitized, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public void Settings_PersistAcrossServiceInstances()
+    {
+        Directory.CreateDirectory(_root);
+        var path = Path.Combine(_root, "rss.db");
+        using (var first = new RssReaderService(path)) first.SaveSettings(new RssReaderSettings(60, 45, true));
+        using var second = new RssReaderService(path);
+        Assert.Equal(new RssReaderSettings(60, 45, true), second.GetSettings());
+    }
+
+    [Fact]
+    public void ExportOpml_CreatesValidEmptyDocument()
+    {
+        Directory.CreateDirectory(_root);
+        using var service = new RssReaderService(Path.Combine(_root, "rss.db"));
+        var path = Path.Combine(_root, "feeds.opml");
+        service.ExportOpml(path);
+        var document = XDocument.Load(path);
+        Assert.Equal("opml", document.Root?.Name.LocalName);
+    }
+
+    public void Dispose()
+    {
+        SqliteConnection.ClearAllPools();
+        if (Directory.Exists(_root)) Directory.Delete(_root, true);
+    }
+}
diff --git a/LanMountainDesktop/Services/RssReader/RssReaderService.cs b/LanMountainDesktop/Services/RssReader/RssReaderService.cs
new file mode 100644
index 0000000..cef41e5
--- /dev/null
+++ b/LanMountainDesktop/Services/RssReader/RssReaderService.cs
@@ -0,0 +1,665 @@
+using System.Net;
+using System.Net.Http.Headers;
+using System.Security.Cryptography;
+using System.ServiceModel.Syndication;
+using System.Text;
+using System.Text.RegularExpressions;
+using System.Xml;
+using System.Xml.Linq;
+using Microsoft.Data.Sqlite;
+
+namespace LanMountainDesktop.Services.RssReader;
+
+public sealed record RssSource(
+    string Id,
+    string Title,
+    string FeedUrl,
+    string? SiteUrl,
+    string? Folder,
+    bool IsEnabled,
+    int? RefreshIntervalMinutes,
+    string? ETag,
+    DateTimeOffset? LastModified,
+    DateTimeOffset? LastRefresh,
+    string? LastError);
+
+public sealed record RssEntry(
+    string Id,
+    string SourceId,
+    string SourceTitle,
+    string Title,
+    string? Link,
+    string? Author,
+    string Summary,
+    string Content,
+    DateTimeOffset PublishedAt,
+    bool IsRead,
+    bool IsFavorite);
+
+public sealed record RssReaderSettings(int RefreshIntervalMinutes, int RetentionDays, bool LoadRemoteImages)
+{
+    public static RssReaderSettings Default { get; } = new(30, 30, false);
+}
+
+public sealed record RssFeedProbe(string Title, string FeedUrl, string? SiteUrl, string Format);
+
+public sealed record RssOpmlImportResult(int Added, int Skipped, int Failed);
+
+public sealed class RssReaderService : IDisposable
+{
+    private const int MaxResponseBytes = 5 * 1024 * 1024;
+    private const int MaxEntriesPerSource = 500;
+    private static readonly TimeSpan RequestTimeout = TimeSpan.FromSeconds(20);
+    private static readonly HttpClient SharedHttpClient = CreateHttpClient();
+    private readonly string _databasePath;
+    private readonly Timer _revisionTimer;
+    private long _lastRevision;
+    private bool _disposed;
+
+    public RssReaderService(string? databasePath = null)
+    {
+        _databasePath = databasePath ?? Path.Combine(
+            AppDataPathProvider.GetDataRoot(), "AirApps", "RssReader", "rss.db");
+        Directory.CreateDirectory(Path.GetDirectoryName(_databasePath)!);
+        InitializeDatabase();
+        _lastRevision = GetRevision();
+        _revisionTimer = new Timer(CheckRevision, null, TimeSpan.FromSeconds(1), TimeSpan.FromSeconds(1));
+    }
+
+    public event EventHandler? Changed;
+
+    public string DatabasePath => _databasePath;
+
+    public IReadOnlyList<RssSource> GetSources()
+    {
+        using var connection = OpenConnection();
+        using var command = connection.CreateCommand();
+        command.CommandText = """
+            SELECT id, title, feed_url, site_url, folder, enabled, refresh_interval,
+                   etag, last_modified, last_refresh, last_error
+            FROM rss_sources ORDER BY COALESCE(folder, ''), title COLLATE NOCASE;
+            """;
+        using var reader = command.ExecuteReader();
+        var result = new List<RssSource>();
+        while (reader.Read())
+        {
+            result.Add(ReadSource(reader));
+        }
+
+        return result;
+    }
+
+    public IReadOnlyList<RssEntry> GetEntries(
+        string? sourceId = null,
+        bool unreadOnly = false,
+        bool favoritesOnly = false,
+        int limit = 100)
+    {
+        using var connection = OpenConnection();
+        using var command = connection.CreateCommand();
+        var filters = new List<string>();
+        if (!string.IsNullOrWhiteSpace(sourceId))
+        {
+            filters.Add("e.source_id = $sourceId");
+            command.Parameters.AddWithValue("$sourceId", sourceId);
+        }
+        if (unreadOnly) filters.Add("e.is_read = 0");
+        if (favoritesOnly) filters.Add("e.is_favorite = 1");
+        command.Parameters.AddWithValue("$limit", Math.Clamp(limit, 1, 500));
+        command.CommandText = $"""
+            SELECT e.id, e.source_id, s.title, e.title, e.link, e.author,
+                   e.summary, e.content, e.published_at, e.is_read, e.is_favorite
+            FROM rss_entries e JOIN rss_sources s ON s.id = e.source_id
+            {(filters.Count == 0 ? string.Empty : "WHERE " + string.Join(" AND ", filters))}
+            ORDER BY e.published_at DESC LIMIT $limit;
+            """;
+        using var reader = command.ExecuteReader();
+        var result = new List<RssEntry>();
+        while (reader.Read()) result.Add(ReadEntry(reader));
+        return result;
+    }
+
+    public RssEntry? GetEntry(string id)
+    {
+        using var connection = OpenConnection();
+        using var command = connection.CreateCommand();
+        command.CommandText = """
+            SELECT e.id, e.source_id, s.title, e.title, e.link, e.author,
+                   e.summary, e.content, e.published_at, e.is_read, e.is_favorite
+            FROM rss_entries e JOIN rss_sources s ON s.id = e.source_id WHERE e.id = $id;
+            """;
+        command.Parameters.AddWithValue("$id", id);
+        using var reader = command.ExecuteReader();
+        return reader.Read() ? ReadEntry(reader) : null;
+    }
+
+    public async Task<RssFeedProbe> ProbeAsync(string feedUrl, CancellationToken cancellationToken = default)
+    {
+        var normalizedUrl = NormalizeFeedUrl(feedUrl);
+        var document = await DownloadFeedAsync(normalizedUrl, null, null, cancellationToken).ConfigureAwait(false);
+        if (document.NotModified || document.Bytes is null) throw new InvalidDataException("Feed returned no content.");
+        var parsed = ParseFeed(document.Bytes, normalizedUrl);
+        return new RssFeedProbe(parsed.Title, normalizedUrl, parsed.SiteUrl, parsed.Format);
+    }
+
+    public async Task<RssSource> AddSourceAsync(
+        string feedUrl,
+        string? title = null,
+        string? folder = null,
+        CancellationToken cancellationToken = default)
+    {
+        var normalizedUrl = NormalizeFeedUrl(feedUrl);
+        var document = await DownloadFeedAsync(normalizedUrl, null, null, cancellationToken).ConfigureAwait(false);
+        if (document.Bytes is null) throw new InvalidDataException("Feed returned no content.");
+        var parsed = ParseFeed(document.Bytes, normalizedUrl);
+        var sourceId = CreateStableId(normalizedUrl);
+        using var connection = OpenConnection();
+        using var transaction = connection.BeginTransaction();
+        using (var command = connection.CreateCommand())
+        {
+            command.Transaction = transaction;
+            command.CommandText = """
+                INSERT INTO rss_sources(id, title, feed_url, site_url, folder, enabled, etag, last_modified, last_refresh)
+                VALUES($id, $title, $url, $site, $folder, 1, $etag, $modified, $refresh)
+                ON CONFLICT(feed_url) DO UPDATE SET
+                    title = excluded.title, site_url = excluded.site_url,
+                    folder = COALESCE(excluded.folder, rss_sources.folder), enabled = 1;
+                """;
+            command.Parameters.AddWithValue("$id", sourceId);
+            command.Parameters.AddWithValue("$title", string.IsNullOrWhiteSpace(title) ? parsed.Title : title.Trim());
+            command.Parameters.AddWithValue("$url", normalizedUrl);
+            command.Parameters.AddWithValue("$site", (object?)parsed.SiteUrl ?? DBNull.Value);
+            command.Parameters.AddWithValue("$folder", NormalizeOptional(folder));
+            command.Parameters.AddWithValue("$etag", (object?)document.ETag ?? DBNull.Value);
+            command.Parameters.AddWithValue("$modified", ToDb(document.LastModified));
+            command.Parameters.AddWithValue("$refresh", ToDb(DateTimeOffset.UtcNow));
+            command.ExecuteNonQuery();
+        }
+        UpsertEntries(connection, transaction, sourceId, normalizedUrl, parsed.Items);
+        IncrementRevision(connection, transaction);
+        transaction.Commit();
+        RaiseChanged();
+        return GetSources().Single(source => source.FeedUrl == normalizedUrl);
+    }
+
+    public void UpdateSource(string id, string title, string? folder, bool enabled, int? refreshIntervalMinutes)
+    {
+        using var connection = OpenConnection();
+        using var transaction = connection.BeginTransaction();
+        using var command = connection.CreateCommand();
+        command.Transaction = transaction;
+        command.CommandText = """
+            UPDATE rss_sources SET title=$title, folder=$folder, enabled=$enabled,
+                refresh_interval=$interval WHERE id=$id;
+            """;
+        command.Parameters.AddWithValue("$id", id);
+        command.Parameters.AddWithValue("$title", string.IsNullOrWhiteSpace(title) ? "Untitled Feed" : title.Trim());
+        command.Parameters.AddWithValue("$folder", NormalizeOptional(folder));
+        command.Parameters.AddWithValue("$enabled", enabled ? 1 : 0);
+        command.Parameters.AddWithValue("$interval", refreshIntervalMinutes is null ? DBNull.Value : Math.Clamp(refreshIntervalMinutes.Value, 15, 1440));
+        command.ExecuteNonQuery();
+        IncrementRevision(connection, transaction);
+        transaction.Commit();
+        RaiseChanged();
+    }
+
+    public void DeleteSource(string id, bool preserveFavorites)
+    {
+        using var connection = OpenConnection();
+        using var transaction = connection.BeginTransaction();
+        if (preserveFavorites)
+        {
+            using var preserve = connection.CreateCommand();
+            preserve.Transaction = transaction;
+            preserve.CommandText = "DELETE FROM rss_entries WHERE source_id=$id AND is_favorite=0; UPDATE rss_sources SET enabled=0 WHERE id=$id;";
+            preserve.Parameters.AddWithValue("$id", id);
+            preserve.ExecuteNonQuery();
+        }
+        else
+        {
+            using var delete = connection.CreateCommand();
+            delete.Transaction = transaction;
+            delete.CommandText = "DELETE FROM rss_sources WHERE id=$id;";
+            delete.Parameters.AddWithValue("$id", id);
+            delete.ExecuteNonQuery();
+        }
+        IncrementRevision(connection, transaction);
+        transaction.Commit();
+        RaiseChanged();
+    }
+
+    public void MarkRead(string entryId, bool isRead = true) => UpdateEntryFlag(entryId, "is_read", isRead);
+    public void SetFavorite(string entryId, bool isFavorite) => UpdateEntryFlag(entryId, "is_favorite", isFavorite);
+
+    public void MarkAllRead(string? sourceId = null)
+    {
+        using var connection = OpenConnection();
+        using var transaction = connection.BeginTransaction();
+        using var command = connection.CreateCommand();
+        command.Transaction = transaction;
+        command.CommandText = sourceId is null
+            ? "UPDATE rss_entries SET is_read=1 WHERE is_read=0;"
+            : "UPDATE rss_entries SET is_read=1 WHERE is_read=0 AND source_id=$sourceId;";
+        if (sourceId is not null) command.Parameters.AddWithValue("$sourceId", sourceId);
+        command.ExecuteNonQuery();
+        IncrementRevision(connection, transaction);
+        transaction.Commit();
+        RaiseChanged();
+    }
+
+    public RssReaderSettings GetSettings()
+    {
+        using var connection = OpenConnection();
+        using var command = connection.CreateCommand();
+        command.CommandText = "SELECT value FROM rss_metadata WHERE key='settings';";
+        var value = command.ExecuteScalar() as string;
+        if (string.IsNullOrWhiteSpace(value)) return RssReaderSettings.Default;
+        var parts = value.Split('|');
+        return new RssReaderSettings(
+            parts.Length > 0 && int.TryParse(parts[0], out var refresh) ? refresh : 30,
+            parts.Length > 1 && int.TryParse(parts[1], out var retention) ? retention : 30,
+            parts.Length > 2 && bool.TryParse(parts[2], out var images) && images);
+    }
+
+    public void SaveSettings(RssReaderSettings settings)
+    {
+        using var connection = OpenConnection();
+        using var transaction = connection.BeginTransaction();
+        SetMetadata(connection, transaction, "settings", $"{NormalizeRefresh(settings.RefreshIntervalMinutes)}|{Math.Clamp(settings.RetentionDays, 1, 365)}|{settings.LoadRemoteImages}");
+        IncrementRevision(connection, transaction);
+        transaction.Commit();
+        RaiseChanged();
+    }
+
+    public string? GetPendingEntryId()
+    {
+        using var connection = OpenConnection();
+        using var command = connection.CreateCommand();
+        command.CommandText = "SELECT value FROM rss_metadata WHERE key='pending_entry';";
+        return command.ExecuteScalar() as string;
+    }
+
+    public void SetPendingEntryId(string? entryId)
+    {
+        if (string.IsNullOrWhiteSpace(entryId)) return;
+        using var connection = OpenConnection();
+        using var transaction = connection.BeginTransaction();
+        SetMetadata(connection, transaction, "pending_entry", entryId.Trim());
+        IncrementRevision(connection, transaction);
+        transaction.Commit();
+        RaiseChanged();
+    }
+
+    public async Task RefreshAllAsync(bool force = true, CancellationToken cancellationToken = default)
+    {
+        var globalInterval = GetSettings().RefreshIntervalMinutes;
+        var now = DateTimeOffset.UtcNow;
+        var sources = GetSources().Where(source =>
+        {
+            if (!source.IsEnabled) return false;
+            if (force) return true;
+            var interval = source.RefreshIntervalMinutes ?? globalInterval;
+            return interval > 0 && (source.LastRefresh is null || now - source.LastRefresh >= TimeSpan.FromMinutes(interval));
+        }).ToArray();
+        using var gate = new SemaphoreSlim(4);
+        await Task.WhenAll(sources.Select(async source =>
+        {
+            await gate.WaitAsync(cancellationToken).ConfigureAwait(false);
+            try { await RefreshSourceAsync(source.Id, cancellationToken).ConfigureAwait(false); }
+            finally { gate.Release(); }
+        })).ConfigureAwait(false);
+        Cleanup();
+    }
+
+    public async Task RefreshSourceAsync(string sourceId, CancellationToken cancellationToken = default)
+    {
+        var source = GetSources().FirstOrDefault(item => item.Id == sourceId)
+            ?? throw new KeyNotFoundException("RSS source was not found.");
+        try
+        {
+            var document = await DownloadFeedAsync(source.FeedUrl, source.ETag, source.LastModified, cancellationToken).ConfigureAwait(false);
+            using var connection = OpenConnection();
+            using var transaction = connection.BeginTransaction();
+            if (!document.NotModified && document.Bytes is not null)
+            {
+                var parsed = ParseFeed(document.Bytes, source.FeedUrl);
+                UpsertEntries(connection, transaction, source.Id, source.FeedUrl, parsed.Items);
+            }
+            using var update = connection.CreateCommand();
+            update.Transaction = transaction;
+            update.CommandText = "UPDATE rss_sources SET etag=$etag,last_modified=$modified,last_refresh=$refresh,last_error=NULL WHERE id=$id;";
+            update.Parameters.AddWithValue("$id", source.Id);
+            update.Parameters.AddWithValue("$etag", (object?)document.ETag ?? (object?)source.ETag ?? DBNull.Value);
+            update.Parameters.AddWithValue("$modified", ToDb(document.LastModified ?? source.LastModified));
+            update.Parameters.AddWithValue("$refresh", ToDb(DateTimeOffset.UtcNow));
+            update.ExecuteNonQuery();
+            IncrementRevision(connection, transaction);
+            transaction.Commit();
+            RaiseChanged();
+        }
+        catch (Exception ex) when (ex is not OperationCanceledException)
+        {
+            using var connection = OpenConnection();
+            using var command = connection.CreateCommand();
+            command.CommandText = "UPDATE rss_sources SET last_error=$error,last_refresh=$refresh WHERE id=$id;";
+            command.Parameters.AddWithValue("$id", source.Id);
+            command.Parameters.AddWithValue("$error", ex.Message);
+            command.Parameters.AddWithValue("$refresh", ToDb(DateTimeOffset.UtcNow));
+            command.ExecuteNonQuery();
+        }
+    }
+
+    public async Task<RssOpmlImportResult> ImportOpmlAsync(string path, CancellationToken cancellationToken = default)
+    {
+        var document = XDocument.Load(path, LoadOptions.None);
+        var outlines = document.Descendants("outline")
+            .Where(element => element.Attribute("xmlUrl") is not null)
+            .Select(element => new
+            {
+                Url = element.Attribute("xmlUrl")!.Value,
+                Title = element.Attribute("title")?.Value ?? element.Attribute("text")?.Value,
+                Folder = string.Join(" / ", element.Ancestors("outline").Reverse()
+                    .Select(ancestor => ancestor.Attribute("text")?.Value)
+                    .Where(value => !string.IsNullOrWhiteSpace(value)))
+            }).ToArray();
+        var existing = GetSources().Select(source => source.FeedUrl).ToHashSet(StringComparer.OrdinalIgnoreCase);
+        var added = 0; var skipped = 0; var failed = 0;
+        foreach (var outline in outlines)
+        {
+            try
+            {
+                var normalized = NormalizeFeedUrl(outline.Url);
+                if (!existing.Add(normalized)) { skipped++; continue; }
+                await AddSourceAsync(normalized, outline.Title, outline.Folder, cancellationToken).ConfigureAwait(false);
+                added++;
+            }
+            catch (Exception ex) when (ex is not OperationCanceledException) { failed++; }
+        }
+        return new RssOpmlImportResult(added, skipped, failed);
+    }
+
+    public void ExportOpml(string path)
+    {
+        var body = new XElement("body");
+        foreach (var group in GetSources().GroupBy(source => source.Folder ?? string.Empty))
+        {
+            var parent = string.IsNullOrWhiteSpace(group.Key) ? body : new XElement("outline", new XAttribute("text", group.Key));
+            foreach (var source in group)
+            {
+                parent.Add(new XElement("outline",
+                    new XAttribute("type", "rss"), new XAttribute("text", source.Title),
+                    new XAttribute("title", source.Title), new XAttribute("xmlUrl", source.FeedUrl),
+                    source.SiteUrl is null ? null : new XAttribute("htmlUrl", source.SiteUrl)));
+            }
+            if (parent != body) body.Add(parent);
+        }
+        new XDocument(new XDeclaration("1.0", "utf-8", null),
+            new XElement("opml", new XAttribute("version", "2.0"),
+                new XElement("head", new XElement("title", "LanMountainDesktop RSS subscriptions")), body)).Save(path);
+    }
+
+    public static string NormalizeFeedUrl(string value)
+    {
+        if (!Uri.TryCreate(value?.Trim(), UriKind.Absolute, out var uri) ||
+            (uri.Scheme != Uri.UriSchemeHttp && uri.Scheme != Uri.UriSchemeHttps))
+            throw new ArgumentException("RSS address must be an absolute HTTP or HTTPS URL.", nameof(value));
+        var builder = new UriBuilder(uri) { Fragment = string.Empty, Host = uri.Host.ToLowerInvariant() };
+        if ((builder.Scheme == "https" && builder.Port == 443) || (builder.Scheme == "http" && builder.Port == 80)) builder.Port = -1;
+        return builder.Uri.AbsoluteUri.TrimEnd('/');
+    }
+
+    internal static RssFeedProbe ParseProbe(byte[] bytes, string feedUrl)
+    {
+        var parsed = ParseFeed(bytes, NormalizeFeedUrl(feedUrl));
+        return new RssFeedProbe(parsed.Title, NormalizeFeedUrl(feedUrl), parsed.SiteUrl, parsed.Format);
+    }
+
+    public static string SanitizeHtml(string? html, bool loadRemoteImages)
+    {
+        if (string.IsNullOrWhiteSpace(html)) return string.Empty;
+        var value = Regex.Replace(html, @"<(script|style|iframe|object|embed|form)[^>]*>.*?</\1\s*>", string.Empty, RegexOptions.IgnoreCase | RegexOptions.Singleline);
+        value = Regex.Replace(value, """\s+on[a-z]+\s*=\s*(['"]).*?\1""", string.Empty, RegexOptions.IgnoreCase | RegexOptions.Singleline);
+        value = Regex.Replace(value, """\s+(src|href)\s*=\s*(['"])\s*javascript:.*?\2""", string.Empty, RegexOptions.IgnoreCase | RegexOptions.Singleline);
+        if (!loadRemoteImages) value = Regex.Replace(value, @"<img\b[^>]*>", string.Empty, RegexOptions.IgnoreCase);
+        return value;
+    }
+
+    public static string ToPlainText(string? html)
+    {
+        if (string.IsNullOrWhiteSpace(html)) return string.Empty;
+        var withoutTags = Regex.Replace(html, "<[^>]+>", " ");
+        return Regex.Replace(WebUtility.HtmlDecode(withoutTags), @"\s+", " ").Trim();
+    }
+
+    public void Dispose()
+    {
+        if (_disposed) return;
+        _disposed = true;
+        _revisionTimer.Dispose();
+    }
+
+    private void InitializeDatabase()
+    {
+        using var connection = OpenConnection();
+        using var command = connection.CreateCommand();
+        command.CommandText = """
+            PRAGMA journal_mode=WAL;
+            PRAGMA foreign_keys=ON;
+            CREATE TABLE IF NOT EXISTS rss_sources(
+              id TEXT PRIMARY KEY, title TEXT NOT NULL, feed_url TEXT NOT NULL UNIQUE,
+              site_url TEXT, folder TEXT, enabled INTEGER NOT NULL DEFAULT 1,
+              refresh_interval INTEGER, etag TEXT, last_modified TEXT,
+              last_refresh TEXT, last_error TEXT);
+            CREATE TABLE IF NOT EXISTS rss_entries(
+              id TEXT PRIMARY KEY, source_id TEXT NOT NULL REFERENCES rss_sources(id) ON DELETE CASCADE,
+              title TEXT NOT NULL, link TEXT, author TEXT, summary TEXT NOT NULL DEFAULT '',
+              content TEXT NOT NULL DEFAULT '', published_at TEXT NOT NULL,
+              is_read INTEGER NOT NULL DEFAULT 0, is_favorite INTEGER NOT NULL DEFAULT 0);
+            CREATE INDEX IF NOT EXISTS ix_rss_entries_source_date ON rss_entries(source_id, published_at DESC);
+            CREATE INDEX IF NOT EXISTS ix_rss_entries_date ON rss_entries(published_at DESC);
+            CREATE TABLE IF NOT EXISTS rss_metadata(key TEXT PRIMARY KEY, value TEXT NOT NULL);
+            INSERT OR IGNORE INTO rss_metadata(key,value) VALUES('revision','0');
+            """;
+        command.ExecuteNonQuery();
+    }
+
+    private SqliteConnection OpenConnection()
+    {
+        var connection = new SqliteConnection(new SqliteConnectionStringBuilder
+        {
+            DataSource = _databasePath,
+            Mode = SqliteOpenMode.ReadWriteCreate,
+            Cache = SqliteCacheMode.Shared,
+            Pooling = true
+        }.ToString());
+        connection.Open();
+        using var command = connection.CreateCommand();
+        command.CommandText = "PRAGMA foreign_keys=ON; PRAGMA busy_timeout=5000;";
+        command.ExecuteNonQuery();
+        return connection;
+    }
+
+    private static HttpClient CreateHttpClient()
+    {
+        var client = new HttpClient(new SocketsHttpHandler { AutomaticDecompression = DecompressionMethods.All })
+        { Timeout = RequestTimeout };
+        client.DefaultRequestHeaders.UserAgent.ParseAdd("LanMountainDesktop-RssReader/1.0");
+        return client;
+    }
+
+    private static async Task<DownloadResult> DownloadFeedAsync(string url, string? etag, DateTimeOffset? modified, CancellationToken token)
+    {
+        using var request = new HttpRequestMessage(HttpMethod.Get, url);
+        if (!string.IsNullOrWhiteSpace(etag) && EntityTagHeaderValue.TryParse(etag, out var tag)) request.Headers.IfNoneMatch.Add(tag);
+        if (modified is not null) request.Headers.IfModifiedSince = modified;
+        using var response = await SharedHttpClient.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, token).ConfigureAwait(false);
+        if (response.StatusCode == HttpStatusCode.NotModified) return new DownloadResult(null, etag, modified, true);
+        response.EnsureSuccessStatusCode();
+        if (response.Content.Headers.ContentLength > MaxResponseBytes) throw new InvalidDataException("RSS response exceeds 5 MB.");
+        await using var stream = await response.Content.ReadAsStreamAsync(token).ConfigureAwait(false);
+        using var memory = new MemoryStream();
+        var buffer = new byte[81920];
+        int read;
+        while ((read = await stream.ReadAsync(buffer, token).ConfigureAwait(false)) > 0)
+        {
+            if (memory.Length + read > MaxResponseBytes) throw new InvalidDataException("RSS response exceeds 5 MB.");
+            memory.Write(buffer, 0, read);
+        }
+        return new DownloadResult(memory.ToArray(), response.Headers.ETag?.ToString(), response.Content.Headers.LastModified, false);
+    }
+
+    private static ParsedFeed ParseFeed(byte[] bytes, string feedUrl)
+    {
+        var settings = new XmlReaderSettings { DtdProcessing = DtdProcessing.Prohibit, XmlResolver = null, MaxCharactersInDocument = MaxResponseBytes };
+        using var stream = new MemoryStream(bytes);
+        using var reader = XmlReader.Create(stream, settings);
+        var feed = SyndicationFeed.Load(reader) ?? throw new InvalidDataException("Unsupported RSS or Atom document.");
+        var title = string.IsNullOrWhiteSpace(feed.Title?.Text) ? new Uri(feedUrl).Host : feed.Title.Text.Trim();
+        var siteUrl = ResolveLink(feed.Links.FirstOrDefault(link => link.RelationshipType is null or "alternate")?.Uri, feedUrl);
+        var items = feed.Items.Select(item =>
+        {
+            var link = ResolveLink(item.Links.FirstOrDefault(link => link.RelationshipType is null or "alternate")?.Uri, feedUrl);
+            var published = item.PublishDate != DateTimeOffset.MinValue ? item.PublishDate :
+                item.LastUpdatedTime != DateTimeOffset.MinValue ? item.LastUpdatedTime : DateTimeOffset.UtcNow;
+            var summary = item.Summary?.Text ?? string.Empty;
+            var content = item.Content is TextSyndicationContent textContent ? textContent.Text : summary;
+            var stable = !string.IsNullOrWhiteSpace(item.Id) ? item.Id : link ?? $"{item.Title?.Text}|{published:O}";
+            return new ParsedItem(CreateStableId(feedUrl + "|" + stable), item.Title?.Text?.Trim() ?? "Untitled", link,
+                item.Authors.FirstOrDefault()?.Name, summary, content, published);
+        }).ToArray();
+        var format = Encoding.UTF8.GetString(bytes.AsSpan(0, Math.Min(bytes.Length, 512))).Contains("<feed", StringComparison.OrdinalIgnoreCase) ? "Atom" : "RSS";
+        return new ParsedFeed(title, siteUrl, format, items);
+    }
+
+    private static void UpsertEntries(SqliteConnection connection, SqliteTransaction transaction, string sourceId, string feedUrl, IEnumerable<ParsedItem> items)
+    {
+        foreach (var item in items)
+        {
+            using var command = connection.CreateCommand();
+            command.Transaction = transaction;
+            command.CommandText = """
+                INSERT INTO rss_entries(id,source_id,title,link,author,summary,content,published_at)
+                VALUES($id,$source,$title,$link,$author,$summary,$content,$published)
+                ON CONFLICT(id) DO UPDATE SET title=excluded.title,link=excluded.link,author=excluded.author,
+                    summary=excluded.summary,content=excluded.content,published_at=excluded.published_at;
+                """;
+            command.Parameters.AddWithValue("$id", item.Id);
+            command.Parameters.AddWithValue("$source", sourceId);
+            command.Parameters.AddWithValue("$title", item.Title);
+            command.Parameters.AddWithValue("$link", (object?)item.Link ?? DBNull.Value);
+            command.Parameters.AddWithValue("$author", (object?)item.Author ?? DBNull.Value);
+            command.Parameters.AddWithValue("$summary", item.Summary);
+            command.Parameters.AddWithValue("$content", item.Content);
+            command.Parameters.AddWithValue("$published", ToDb(item.PublishedAt));
+            command.ExecuteNonQuery();
+        }
+    }
+
+    private static string? ResolveLink(Uri? link, string feedUrl)
+    {
+        if (link is null) return null;
+        if (link.IsAbsoluteUri) return link.AbsoluteUri;
+        return Uri.TryCreate(new Uri(feedUrl), link, out var absolute) ? absolute.AbsoluteUri : null;
+    }
+
+    private void Cleanup()
+    {
+        var retention = GetSettings().RetentionDays;
+        using var connection = OpenConnection();
+        using var transaction = connection.BeginTransaction();
+        using var command = connection.CreateCommand();
+        command.Transaction = transaction;
+        command.CommandText = """
+            DELETE FROM rss_entries WHERE is_favorite=0 AND published_at < $cutoff;
+            DELETE FROM rss_entries WHERE is_favorite=0 AND id IN (
+              SELECT id FROM (SELECT id, ROW_NUMBER() OVER(PARTITION BY source_id ORDER BY published_at DESC) row_number FROM rss_entries)
+              WHERE row_number > $limit);
+            """;
+        command.Parameters.AddWithValue("$cutoff", ToDb(DateTimeOffset.UtcNow.AddDays(-retention)));
+        command.Parameters.AddWithValue("$limit", MaxEntriesPerSource);
+        command.ExecuteNonQuery();
+        IncrementRevision(connection, transaction);
+        transaction.Commit();
+    }
+
+    private void UpdateEntryFlag(string entryId, string column, bool value)
+    {
+        using var connection = OpenConnection();
+        using var transaction = connection.BeginTransaction();
+        using var command = connection.CreateCommand();
+        command.Transaction = transaction;
+        command.CommandText = $"UPDATE rss_entries SET {column}=$value WHERE id=$id;";
+        command.Parameters.AddWithValue("$id", entryId);
+        command.Parameters.AddWithValue("$value", value ? 1 : 0);
+        command.ExecuteNonQuery();
+        IncrementRevision(connection, transaction);
+        transaction.Commit();
+        RaiseChanged();
+    }
+
+    private long GetRevision()
+    {
+        using var connection = OpenConnection();
+        using var command = connection.CreateCommand();
+        command.CommandText = "SELECT value FROM rss_metadata WHERE key='revision';";
+        return long.TryParse(command.ExecuteScalar()?.ToString(), out var revision) ? revision : 0;
+    }
+
+    private void CheckRevision(object? state)
+    {
+        if (_disposed) return;
+        try
+        {
+            var revision = GetRevision();
+            if (revision == Interlocked.Read(ref _lastRevision)) return;
+            Interlocked.Exchange(ref _lastRevision, revision);
+            Changed?.Invoke(this, EventArgs.Empty);
+        }
+        catch { }
+    }
+
+    private void RaiseChanged()
+    {
+        _lastRevision = GetRevision();
+        Changed?.Invoke(this, EventArgs.Empty);
+    }
+
+    private static void IncrementRevision(SqliteConnection connection, SqliteTransaction transaction)
+    {
+        using var command = connection.CreateCommand();
+        command.Transaction = transaction;
+        command.CommandText = "UPDATE rss_metadata SET value=CAST(value AS INTEGER)+1 WHERE key='revision';";
+        command.ExecuteNonQuery();
+    }
+
+    private static void SetMetadata(SqliteConnection connection, SqliteTransaction transaction, string key, string value)
+    {
+        using var command = connection.CreateCommand();
+        command.Transaction = transaction;
+        command.CommandText = "INSERT INTO rss_metadata(key,value) VALUES($key,$value) ON CONFLICT(key) DO UPDATE SET value=excluded.value;";
+        command.Parameters.AddWithValue("$key", key);
+        command.Parameters.AddWithValue("$value", value);
+        command.ExecuteNonQuery();
+    }
+
+    private static RssSource ReadSource(SqliteDataReader reader) => new(
+        reader.GetString(0), reader.GetString(1), reader.GetString(2), reader.IsDBNull(3) ? null : reader.GetString(3),
+        reader.IsDBNull(4) ? null : reader.GetString(4), reader.GetInt64(5) != 0,
+        reader.IsDBNull(6) ? null : reader.GetInt32(6), reader.IsDBNull(7) ? null : reader.GetString(7),
+        ParseDate(reader, 8), ParseDate(reader, 9), reader.IsDBNull(10) ? null : reader.GetString(10));
+
+    private static RssEntry ReadEntry(SqliteDataReader reader) => new(
+        reader.GetString(0), reader.GetString(1), reader.GetString(2), reader.GetString(3),
+        reader.IsDBNull(4) ? null : reader.GetString(4), reader.IsDBNull(5) ? null : reader.GetString(5),
+        reader.GetString(6), reader.GetString(7), DateTimeOffset.Parse(reader.GetString(8)), reader.GetInt64(9) != 0, reader.GetInt64(10) != 0);
+
+    private static DateTimeOffset? ParseDate(SqliteDataReader reader, int index) => reader.IsDBNull(index) ? null : DateTimeOffset.Parse(reader.GetString(index));
+    private static object NormalizeOptional(string? value) => string.IsNullOrWhiteSpace(value) ? DBNull.Value : value.Trim();
+    private static object ToDb(DateTimeOffset? value) => value is null ? DBNull.Value : value.Value.ToUniversalTime().ToString("O");
+    private static int NormalizeRefresh(int value) => value is 0 or 15 or 30 or 60 ? value : 30;
+    private static string CreateStableId(string value) => Convert.ToHexString(SHA256.HashData(Encoding.UTF8.GetBytes(value))).ToLowerInvariant();
+
+    private sealed record DownloadResult(byte[]? Bytes, string? ETag, DateTimeOffset? LastModified, bool NotModified);
+    private sealed record ParsedFeed(string Title, string? SiteUrl, string Format, IReadOnlyList<ParsedItem> Items);
+    private sealed record ParsedItem(string Id, string Title, string? Link, string? Author, string Summary, string Content, DateTimeOffset PublishedAt);
+}
diff --git a/LanMountainDesktop/Views/ComponentEditors/RssReaderComponentEditor.cs b/LanMountainDesktop/Views/ComponentEditors/RssReaderComponentEditor.cs
new file mode 100644
index 0000000..8560c1b
--- /dev/null
+++ b/LanMountainDesktop/Views/ComponentEditors/RssReaderComponentEditor.cs
@@ -0,0 +1,63 @@
+using Avalonia.Controls;
+using Avalonia.Layout;
+using LanMountainDesktop.ComponentSystem;
+using LanMountainDesktop.Models;
+using LanMountainDesktop.Services.RssReader;
+
+namespace LanMountainDesktop.Views.ComponentEditors;
+
+public sealed class RssReaderComponentEditor : ComponentEditorViewBase, IDisposable
+{
+    private readonly RssReaderService _service = new();
+    private readonly ComboBox _sourceCombo = new();
+    private readonly CheckBox _unreadFirst = new();
+    private readonly NumericUpDown _displayCount = new() { Minimum = 5, Maximum = 100, Increment = 5 };
+
+    public RssReaderComponentEditor(DesktopComponentEditorContext? context) : base(context)
+    {
+        var snapshot = LoadSnapshot();
+        var options = new List<SourceOption> { new(string.Empty, L("rss.all_sources", "All sources")) };
+        options.AddRange(_service.GetSources().Select(source => new SourceOption(source.Id, source.Title)));
+        _sourceCombo.ItemsSource = options;
+        _sourceCombo.SelectedItem = options.FirstOrDefault(option => option.Id == snapshot.RssReaderSourceId) ?? options[0];
+        _unreadFirst.IsChecked = snapshot.RssReaderUnreadFirst;
+        _displayCount.Value = Math.Clamp(snapshot.RssReaderDisplayCount, 5, 100);
+
+        _unreadFirst.Content = L("rss.unread_first", "Show unread entries first");
+        var save = new Button { Content = L("rss.save", "Save"), HorizontalAlignment = HorizontalAlignment.Right };
+        save.Click += (_, _) => Save();
+        Content = new StackPanel
+        {
+            Spacing = 14,
+            Margin = new Avalonia.Thickness(20),
+            Children =
+            {
+                new TextBlock { Text = L("component.rss_reader", "RSS Reader"), FontSize = 22, FontWeight = Avalonia.Media.FontWeight.SemiBold },
+                new TextBlock { Text = L("rss.instance_settings_description", "These display options apply only to this component instance."), TextWrapping = Avalonia.Media.TextWrapping.Wrap, Opacity = 0.7 },
+                new TextBlock { Text = L("rss.source", "Source") }, _sourceCombo,
+                _unreadFirst,
+                new TextBlock { Text = L("rss.entry_count", "Number of entries") }, _displayCount,
+                save
+            }
+        };
+    }
+
+    public void Dispose() => _service.Dispose();
+
+    private void Save()
+    {
+        var snapshot = LoadSnapshot();
+        snapshot.RssReaderSourceId = (_sourceCombo.SelectedItem as SourceOption)?.Id ?? string.Empty;
+        snapshot.RssReaderUnreadFirst = _unreadFirst.IsChecked == true;
+        snapshot.RssReaderDisplayCount = (int)(_displayCount.Value ?? 20);
+        SaveSnapshot(snapshot,
+            nameof(ComponentSettingsSnapshot.RssReaderSourceId),
+            nameof(ComponentSettingsSnapshot.RssReaderUnreadFirst),
+            nameof(ComponentSettingsSnapshot.RssReaderDisplayCount));
+    }
+
+    private sealed record SourceOption(string Id, string Title)
+    {
+        public override string ToString() => Title;
+    }
+}
diff --git a/LanMountainDesktop/Views/Components/RssReaderWidget.axaml b/LanMountainDesktop/Views/Components/RssReaderWidget.axaml
new file mode 100644
index 0000000..a3051f6
--- /dev/null
+++ b/LanMountainDesktop/Views/Components/RssReaderWidget.axaml
@@ -0,0 +1,76 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:fi="using:FluentIcons.Avalonia"
+             x:Class="LanMountainDesktop.Views.Components.RssReaderWidget">
+  <UserControl.Resources>
+    <ResourceDictionary>
+      <ResourceDictionary.ThemeDictionaries>
+        <ResourceDictionary x:Key="Light">
+          <SolidColorBrush x:Key="RssSurfaceBrush" Color="#FCFCFD"/>
+          <SolidColorBrush x:Key="RssSubtleBrush" Color="#F1F3F6"/>
+          <SolidColorBrush x:Key="RssBorderBrush" Color="#16000000"/>
+        </ResourceDictionary>
+        <ResourceDictionary x:Key="Dark">
+          <SolidColorBrush x:Key="RssSurfaceBrush" Color="#1B2129"/>
+          <SolidColorBrush x:Key="RssSubtleBrush" Color="#2A313C"/>
+          <SolidColorBrush x:Key="RssBorderBrush" Color="#28FFFFFF"/>
+        </ResourceDictionary>
+      </ResourceDictionary.ThemeDictionaries>
+    </ResourceDictionary>
+  </UserControl.Resources>
+
+  <Border x:Name="RootBorder"
+          Background="{DynamicResource RssSurfaceBrush}"
+          BorderBrush="{DynamicResource RssBorderBrush}"
+          BorderThickness="1"
+          CornerRadius="{DynamicResource DesignCornerRadiusComponent}"
+          ClipToBounds="True"
+          Padding="18">
+    <Grid ColumnDefinitions="164,*" ColumnSpacing="18">
+      <Grid RowDefinitions="Auto,*" RowSpacing="12">
+        <StackPanel Spacing="7">
+          <TextBlock x:Name="TitleText" Text="RSS Reader" FontSize="21" FontWeight="SemiBold"/>
+          <TextBlock x:Name="UnreadText" Text="0 unread" FontSize="12" Opacity="0.66"/>
+        </StackPanel>
+
+        <StackPanel Grid.Row="1" VerticalAlignment="Bottom" Spacing="8">
+          <Button x:Name="RefreshButton" HorizontalContentAlignment="Left"
+                  Background="{DynamicResource RssSubtleBrush}" BorderThickness="0">
+            <StackPanel Orientation="Horizontal" Spacing="8">
+              <fi:SymbolIcon Symbol="ArrowSync" FontSize="14"/>
+              <TextBlock x:Name="RefreshButtonText" Text="Refresh" VerticalAlignment="Center"/>
+            </StackPanel>
+          </Button>
+          <Button x:Name="MarkAllReadButton" HorizontalContentAlignment="Left"
+                  Background="{DynamicResource RssSubtleBrush}" BorderThickness="0">
+            <StackPanel Orientation="Horizontal" Spacing="8">
+              <fi:SymbolIcon Symbol="Checkmark" FontSize="14"/>
+              <TextBlock x:Name="MarkAllReadButtonText" Text="Mark all read" VerticalAlignment="Center"/>
+            </StackPanel>
+          </Button>
+          <Button x:Name="OpenReaderButton" HorizontalContentAlignment="Left"
+                  Background="{DynamicResource RssSubtleBrush}" BorderThickness="0">
+            <StackPanel Orientation="Horizontal" Spacing="8">
+              <fi:SymbolIcon Symbol="ArrowRight" FontSize="14"/>
+              <TextBlock x:Name="OpenReaderButtonText" Text="Open reader" VerticalAlignment="Center"/>
+            </StackPanel>
+          </Button>
+        </StackPanel>
+      </Grid>
+
+      <Grid Grid.Column="1" RowDefinitions="Auto,*" RowSpacing="8">
+        <Grid ColumnDefinitions="*,Auto">
+          <TextBlock x:Name="LatestText" Text="Latest articles" FontSize="14" FontWeight="SemiBold" VerticalAlignment="Center"/>
+          <TextBlock x:Name="ErrorText" Grid.Column="1" IsVisible="False" Foreground="#D13438"
+                     FontSize="11" TextTrimming="CharacterEllipsis" MaxWidth="240"/>
+        </Grid>
+        <ScrollViewer Grid.Row="1" VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Disabled">
+          <WrapPanel x:Name="EntriesPanel" Orientation="Horizontal" ItemWidth="220" ItemHeight="88"/>
+        </ScrollViewer>
+        <Button x:Name="EmptyButton" Grid.Row="1" IsVisible="False" HorizontalAlignment="Stretch"
+                VerticalAlignment="Stretch" Background="{DynamicResource RssSubtleBrush}" BorderThickness="0"
+                Content="Import OPML or add your first RSS source"/>
+      </Grid>
+    </Grid>
+  </Border>
+</UserControl>
diff --git a/LanMountainDesktop/Views/Components/RssReaderWidget.axaml.cs b/LanMountainDesktop/Views/Components/RssReaderWidget.axaml.cs
new file mode 100644
index 0000000..0c19382
--- /dev/null
+++ b/LanMountainDesktop/Views/Components/RssReaderWidget.axaml.cs
@@ -0,0 +1,170 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Input;
+using Avalonia.Interactivity;
+using Avalonia.Media;
+using Avalonia.Threading;
+using System.Globalization;
+using LanMountainDesktop.ComponentSystem;
+using LanMountainDesktop.Models;
+using LanMountainDesktop.PluginSdk;
+using LanMountainDesktop.Services;
+using LanMountainDesktop.Services.RssReader;
+using LanMountainDesktop.Services.Settings;
+
+namespace LanMountainDesktop.Views.Components;
+
+public sealed partial class RssReaderWidget : UserControl, IDesktopComponentWidget, IDesktopComponentLifecycleWidget
+{
+    private readonly RssReaderService _service;
+    private readonly IComponentSettingsAccessor _settingsAccessor;
+    private readonly string? _placementId;
+    private readonly LocalizationService _localization = new();
+    private readonly string _languageCode;
+    private readonly DispatcherTimer _refreshTimer = new();
+    private bool _isRefreshing;
+
+    public RssReaderWidget(IComponentSettingsAccessor settingsAccessor, string? placementId)
+    {
+        _settingsAccessor = settingsAccessor;
+        _placementId = placementId;
+        _languageCode = _localization.NormalizeLanguageCode(HostSettingsFacadeProvider.GetOrCreate().Region.Get().LanguageCode);
+        _service = new RssReaderService();
+        InitializeComponent();
+        ApplyLocalization();
+        OpenReaderButton.Click += OnOpen;
+        EmptyButton.Click += OnOpen;
+        RefreshButton.Click += OnRefresh;
+        MarkAllReadButton.Click += OnMarkAllRead;
+        _service.Changed += OnServiceChanged;
+        _refreshTimer.Tick += OnRefreshTimer;
+        AttachedToVisualTree += OnAttached;
+        DetachedFromVisualTree += OnDetached;
+    }
+
+    public void ApplyCellSize(double cellSize) { }
+
+    public void OnWidgetDestroyed() => DisposeResources();
+
+    private void OnAttached(object? sender, VisualTreeAttachmentEventArgs e)
+    {
+        Reload();
+        ConfigureTimer();
+        _ = RefreshAsync(force: true);
+    }
+
+    private void OnDetached(object? sender, VisualTreeAttachmentEventArgs e) => _refreshTimer.Stop();
+
+    private void ConfigureTimer()
+    {
+        var minutes = _service.GetSettings().RefreshIntervalMinutes;
+        if (minutes <= 0) { _refreshTimer.Stop(); return; }
+        _refreshTimer.Interval = TimeSpan.FromMinutes(minutes);
+        _refreshTimer.Start();
+    }
+
+    private async void OnRefreshTimer(object? sender, EventArgs e) => await RefreshAsync(force: false);
+    private async void OnRefresh(object? sender, RoutedEventArgs e) => await RefreshAsync(force: true);
+
+    private async Task RefreshAsync(bool force)
+    {
+        if (_isRefreshing) return;
+        _isRefreshing = true;
+        RefreshButton.IsEnabled = false;
+        ErrorText.IsVisible = false;
+        try { await _service.RefreshAllAsync(force); }
+        catch (Exception ex) { ErrorText.Text = $"{L("rss.refresh_failed", "Refresh failed")}: {ex.Message}"; ErrorText.IsVisible = true; }
+        finally { _isRefreshing = false; RefreshButton.IsEnabled = true; Reload(); }
+    }
+
+    private void OnMarkAllRead(object? sender, RoutedEventArgs e)
+    {
+        var settings = LoadSettings();
+        _service.MarkAllRead(string.IsNullOrWhiteSpace(settings.RssReaderSourceId) ? null : settings.RssReaderSourceId);
+    }
+
+    private void OnOpen(object? sender, RoutedEventArgs e) => OpenReader(null);
+
+    private void OnServiceChanged(object? sender, EventArgs e) => Dispatcher.UIThread.Post(Reload);
+
+    private void Reload()
+    {
+        var settings = LoadSettings();
+        var sourceId = string.IsNullOrWhiteSpace(settings.RssReaderSourceId) ? null : settings.RssReaderSourceId;
+        var entries = _service.GetEntries(sourceId, limit: Math.Clamp(settings.RssReaderDisplayCount, 5, 100));
+        if (settings.RssReaderUnreadFirst)
+            entries = entries.OrderBy(entry => entry.IsRead).ThenByDescending(entry => entry.PublishedAt).ToArray();
+        EntriesPanel.Children.Clear();
+        foreach (var entry in entries)
+        {
+            var button = new Button
+            {
+                HorizontalContentAlignment = Avalonia.Layout.HorizontalAlignment.Stretch,
+                Background = Brushes.Transparent,
+                BorderThickness = new Thickness(0),
+                Padding = new Thickness(8),
+                Tag = entry.Id,
+                Content = new Grid
+                {
+                    RowDefinitions = new RowDefinitions("Auto,Auto"),
+                    Children =
+                    {
+                        new TextBlock { Text = (entry.IsRead ? string.Empty : "● ") + entry.Title, FontWeight = entry.IsRead ? FontWeight.Normal : FontWeight.SemiBold, TextWrapping = TextWrapping.Wrap, MaxLines = 2 },
+                        new TextBlock { Text = $"{entry.SourceTitle} · {FormatRelative(entry.PublishedAt)}{(entry.IsFavorite ? " · ★" : string.Empty)}", FontSize = 11, Opacity = 0.6, Margin = new Thickness(0,4,0,0), [Grid.RowProperty] = 1 }
+                    }
+                }
+            };
+            button.Click += OnEntryClicked;
+            EntriesPanel.Children.Add(button);
+        }
+        var unread = _service.GetEntries(sourceId, unreadOnly: true, limit: 500).Count;
+        UnreadText.Text = string.Format(L("rss.unread_count", "{0} unread"), unread);
+        EmptyButton.IsVisible = _service.GetSources().Count == 0;
+        EntriesPanel.IsVisible = !EmptyButton.IsVisible;
+    }
+
+    private void OnEntryClicked(object? sender, RoutedEventArgs e)
+    {
+        if (sender is not Button { Tag: string id }) return;
+        _service.MarkRead(id);
+        OpenReader(id);
+    }
+
+    private void OpenReader(string? entryId) => AirAppLauncherServiceProvider.GetOrCreate()
+        .OpenRssReader(BuiltInComponentIds.DesktopRssReader, _placementId, entryId);
+
+    private ComponentSettingsSnapshot LoadSettings() =>
+        _settingsAccessor.LoadSnapshot<ComponentSettingsSnapshot>() ?? new ComponentSettingsSnapshot();
+
+    private string FormatRelative(DateTimeOffset value)
+    {
+        var elapsed = DateTimeOffset.Now - value.ToLocalTime();
+        if (elapsed.TotalMinutes < 1) return L("rss.just_now", "Just now");
+        if (elapsed.TotalHours < 1)
+            return string.Format(L("rss.minutes_ago", "{0} min ago"), (int)elapsed.TotalMinutes);
+        if (elapsed.TotalDays < 1)
+            return string.Format(L("rss.hours_ago", "{0} hr ago"), (int)elapsed.TotalHours);
+
+        var culture = CultureInfo.GetCultureInfo(_languageCode);
+        return value.ToLocalTime().ToString(L("rss.short_date_format", "MMM d"), culture);
+    }
+
+    private void ApplyLocalization()
+    {
+        TitleText.Text = L("component.rss_reader", "RSS Reader");
+        LatestText.Text = L("rss.latest_articles", "Latest articles");
+        RefreshButtonText.Text = L("rss.refresh", "Refresh");
+        MarkAllReadButtonText.Text = L("rss.mark_all_read", "Mark all read");
+        OpenReaderButtonText.Text = L("rss.open_reader", "Open reader");
+        EmptyButton.Content = L("rss.empty", "Import OPML or add your first RSS source");
+    }
+
+    private string L(string key, string fallback) => _localization.GetString(_languageCode, key, fallback);
+
+    private void DisposeResources()
+    {
+        _refreshTimer.Stop();
+        _service.Changed -= OnServiceChanged;
+        _service.Dispose();
+    }
+}