feat(ui): add ImageCacheService, ImageLoader control, and Avalonia XAML converters

GenHub/GenHub.Core/Constants/ImageCacheConstants.cs

@@ -0,0 +1,37 @@
+namespace GenHub.Core.Constants;
+
+/// <summary>
+/// Constants for image downloading, validation, and caching.
+/// </summary>
+public static class ImageCacheConstants
+{
+    /// <summary>
+    /// Maximum allowed image download payload in bytes (15 MB).
+    /// </summary>
+    public const long MaxImageDownloadSizeBytes = 15L * 1024 * 1024;
+
+    /// <summary>
+    /// Maximum number of bitmap entries stored in the memory LRU cache.
+    /// </summary>
+    public const int MaxMemoryCacheEntries = 200;
+
+    /// <summary>
+    /// Maximum disk cache size in bytes (250 MB).
+    /// </summary>
+    public const long MaxDiskCacheSizeBytes = 250L * 1024 * 1024;
+
+    /// <summary>
+    /// Time-to-live for disk-cached images in days.
+    /// </summary>
+    public const int DiskCacheTtlDays = 30;
+
+    /// <summary>
+    /// Default HTTP timeout in seconds for downloading images.
+    /// </summary>
+    public const int DefaultTimeoutSeconds = 30;
+
+    /// <summary>
+    /// Maximum allowed HTTP redirects when downloading images.
+    /// </summary>
+    public const int MaxRedirects = 5;
+}

GenHub/GenHub.Core/Constants/UiConstants.cs

@@ -25,6 +25,21 @@ public static class UiConstants
     /// </summary>
     public const double DefaultProfileSettingsHeight = 700;
 
+    /// <summary>
+    /// Default width for the profile settings sidebar in pixels.
+    /// </summary>
+    public const double DefaultProfileSettingsSidebarWidth = 190;
+
+    /// <summary>
+    /// Minimum width for the profile settings sidebar (shows icons only) in pixels.
+    /// </summary>
+    public const double MinProfileSettingsSidebarWidth = 68;
+
+    /// <summary>
+    /// Maximum width for the profile settings sidebar in pixels.
+    /// </summary>
+    public const double MaxProfileSettingsSidebarWidth = 300;
+
     // Status colors
 
     /// <summary>
@@ -37,6 +52,36 @@ public static class UiConstants
     /// </summary>
     public const string StatusErrorColor = "#F44336";
 
+    /// <summary>
+    /// color used for downloaded status indicator.
+    /// </summary>
+    public const string StatusDownloadedColor = "#4CAF50";
+
+    /// <summary>
+    /// color used for not downloaded status indicator.
+    /// </summary>
+    public const string StatusNotDownloadedColor = "#B388FF";
+
+    /// <summary>
+    /// color used for update available status indicator.
+    /// </summary>
+    public const string StatusUpdateAvailableColor = "#FFB74D";
+
+    /// <summary>
+    /// svg path data for transparent checkmark icon.
+    /// </summary>
+    public const string TransparentCheckmarkIconPath = "M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z";
+
+    /// <summary>
+    /// svg path data for detailed download arrow icon into tray.
+    /// </summary>
+    public const string DownloadArrowIconPath = "M5 20h14v-2H5v2zM19 9h-4V3H9v6H5l7 7 7-7z";
+
+    /// <summary>
+    /// svg path data for update sync icon.
+    /// </summary>
+    public const string UpdateSyncIconPath = "M12 4V1L8 5l4 4V6c3.31 0 6 2.69 6 6 0 1.01-.25 1.97-.7 2.8l1.46 1.46A7.93 7.93 0 0 0 20 12c0-4.42-3.58-8-8-8zm0 14c-3.31 0-6-2.69-6-6 0-1.01.25-1.97.7-2.8L5.24 7.74A7.93 7.93 0 0 0 4 12c0 4.42 3.58 8 8 8v3l4-4-4-4v3z";
+
     /// <summary>
     /// Default theme color for Generals content.
     /// </summary>

GenHub/GenHub.Core/Helpers/HtmlTextHelper.cs

@@ -0,0 +1,145 @@
+using System;
+using System.Net;
+using System.Text.RegularExpressions;
+
+namespace GenHub.Core.Helpers;
+
+/// <summary>
+/// Provides high-performance utilities for stripping HTML tags, decoding HTML entities,
+/// and normalizing text descriptions for display across the application.
+/// </summary>
+public static partial class HtmlTextHelper
+{
+    /// <summary>
+    /// Converts an HTML snippet or formatted description into clean, normalized plain text:
+    /// - Replaces &lt;br&gt; and block element closures (&lt;/p&gt;, &lt;/div&gt;, etc.) with line breaks.
+    /// - Strips all remaining HTML tags.
+    /// - Decodes HTML entities (e.g., &amp;amp;, &amp;quot;, &amp;gt;, &amp;nbsp;).
+    /// - Normalizes whitespace and excessive blank lines.
+    /// - Uses the platform newline format.
+    /// </summary>
+    /// <param name="html">The raw HTML or formatted text string to normalize.</param>
+    /// <returns>Normalized plain text, or empty string if input is null or whitespace.</returns>
+    public static string NormalizeHtml(string? html)
+    {
+        if (string.IsNullOrWhiteSpace(html))
+        {
+            return string.Empty;
+        }
+
+        // 0. Remove script and style elements along with their contents
+        var text = ScriptTagRegex().Replace(html, string.Empty);
+        text = StyleTagRegex().Replace(text, string.Empty);
+
+        // 1. Convert <br> tags to newline
+        text = BrTagRegex().Replace(text, "\n");
+
+        // 2. Convert paragraph closing tags to double newline for paragraph separation
+        text = ParagraphCloseTagRegex().Replace(text, "\n\n");
+
+        // 3. Convert other block-level closing tags and <hr> tags to newline
+        text = BlockCloseTagRegex().Replace(text, "\n");
+
+        // 4. Strip all remaining HTML/XML tags
+        text = HtmlTagRegex().Replace(text, string.Empty);
+
+        // 5. Decode HTML entities (&nbsp;, &gt;, &quot;, &#39;, numeric entities, etc.)
+        text = WebUtility.HtmlDecode(text);
+
+        // 6. Normalize non-breaking spaces and line endings
+        text = text.Replace('\u00A0', ' ')
+                   .Replace("\r\n", "\n")
+                   .Replace('\r', '\n');
+
+        // 7. Clean trailing whitespace on lines and collapse excess blank lines
+        text = TrailingWhitespaceBeforeNewlineRegex().Replace(text, "\n");
+        text = ExcessBlankLinesRegex().Replace(text, "\n\n");
+
+        // 8. Trim and unify with environment newline
+        text = text.Trim();
+        text = text.Replace("\n", Environment.NewLine);
+
+        return text;
+    }
+
+    /// <summary>
+    /// Converts an HTML snippet or multi-line text into a single-line summary without HTML tags,
+    /// collapsing all whitespace runs into a single space, and optionally truncating with an ellipsis.
+    /// </summary>
+    /// <param name="htmlOrText">The input HTML or text string.</param>
+    /// <param name="maxLength">Optional maximum character length including ellipsis.</param>
+    /// <returns>A single-line plain text summary.</returns>
+    public static string CleanToSingleLine(string? htmlOrText, int? maxLength = null)
+    {
+        if (string.IsNullOrWhiteSpace(htmlOrText))
+        {
+            return string.Empty;
+        }
+
+        // Strip HTML if tags exist, decode entities, and normalize
+        var text = NormalizeHtml(htmlOrText);
+
+        // Collapse all newlines, tabs, and multiple spaces into a single space
+        text = MultiWhitespaceRegex().Replace(text, " ").Trim();
+
+        if (maxLength.HasValue && maxLength.Value > 0 && text.Length > maxLength.Value)
+        {
+            return TruncateWithEllipsis(text, maxLength.Value);
+        }
+
+        return text;
+    }
+
+    /// <summary>
+    /// Truncates a string to a specified maximum length and appends an ellipsis ("...") if truncated.
+    /// </summary>
+    /// <param name="text">The text to truncate.</param>
+    /// <param name="maxLength">The maximum allowed length (including the ellipsis).</param>
+    /// <returns>The truncated text with an ellipsis if it exceeded maxLength, or the original text.</returns>
+    public static string TruncateWithEllipsis(string? text, int maxLength)
+    {
+        if (string.IsNullOrWhiteSpace(text) || maxLength <= 0)
+        {
+            return string.Empty;
+        }
+
+        if (text.Length <= maxLength)
+        {
+            return text;
+        }
+
+        if (maxLength <= 3)
+        {
+            return text[..maxLength];
+        }
+
+        return string.Concat(text.AsSpan(0, maxLength - 3), "...");
+    }
+
+    [GeneratedRegex(@"<script\b[^>]*>[\s\S]*?</script>", RegexOptions.IgnoreCase | RegexOptions.CultureInvariant)]
+    private static partial Regex ScriptTagRegex();
+
+    [GeneratedRegex(@"<style\b[^>]*>[\s\S]*?</style>", RegexOptions.IgnoreCase | RegexOptions.CultureInvariant)]
+    private static partial Regex StyleTagRegex();
+
+    [GeneratedRegex(@"<br\s*/?>", RegexOptions.IgnoreCase | RegexOptions.CultureInvariant)]
+    private static partial Regex BrTagRegex();
+
+    [GeneratedRegex(@"</p\s*>", RegexOptions.IgnoreCase | RegexOptions.CultureInvariant)]
+    private static partial Regex ParagraphCloseTagRegex();
+
+    [GeneratedRegex(@"</?(?:div|li|h[1-6]|tr|section|article|blockquote|header|footer|hr)\b[^>]*>", RegexOptions.IgnoreCase | RegexOptions.CultureInvariant)]
+    private static partial Regex BlockCloseTagRegex();
+
+    [GeneratedRegex(@"</?[A-Za-z][^>]*>", RegexOptions.CultureInvariant)]
+    private static partial Regex HtmlTagRegex();
+
+    [GeneratedRegex(@"[ \t]+\n", RegexOptions.CultureInvariant)]
+    private static partial Regex TrailingWhitespaceBeforeNewlineRegex();
+
+    [GeneratedRegex(@"(?:\n){3,}", RegexOptions.CultureInvariant)]
+    private static partial Regex ExcessBlankLinesRegex();
+
+    [GeneratedRegex(@"\s+", RegexOptions.CultureInvariant)]
+    private static partial Regex MultiWhitespaceRegex();
+}

GenHub/GenHub.Core/Models/Enums/ContentState.cs

@@ -0,0 +1,23 @@
+namespace GenHub.Core.Models.Enums;
+
+/// <summary>
+/// Content state for UI display - determines which button to show.
+/// </summary>
+public enum ContentState
+{
+    /// <summary>
+    /// Content has not been downloaded yet. Show "Download" button.
+    /// </summary>
+    NotDownloaded,
+
+    /// <summary>
+    /// Content exists locally but a newer version is available (same publisher+name, newer date).
+    /// Show "Update" button.
+    /// </summary>
+    UpdateAvailable,
+
+    /// <summary>
+    /// Content is downloaded and up-to-date. Show "Add to Profile" dropdown.
+    /// </summary>
+    Downloaded,
+}

GenHub/GenHub.Tests/GenHub.Tests.Core/Converters/StripHtmlConverterTests.cs

@@ -0,0 +1,82 @@
+using System;
+using System.Globalization;
+using GenHub.Infrastructure.Converters;
+using Xunit;
+
+namespace GenHub.Tests.Core.Converters;
+
+/// <summary>
+/// Unit tests for <see cref="StripHtmlConverter"/>.
+/// </summary>
+public sealed class StripHtmlConverterTests
+{
+    private readonly StripHtmlConverter _converter = new();
+
+    /// <summary>
+    /// Verifies Convert strips HTML tags and normalizes text.
+    /// </summary>
+    [Fact]
+    public void Convert_WithHtmlMarkup_StripsTags()
+    {
+        var input = "<p>Test <b>content</b> with <a href=\"#\">links</a>.</p>";
+        var result = _converter.Convert(input, typeof(string), null, CultureInfo.InvariantCulture);
+
+        Assert.Equal("Test content with links.", result);
+    }
+
+    /// <summary>
+    /// Verifies Convert with integer parameter truncates and single-lines text.
+    /// </summary>
+    [Fact]
+    public void Convert_WithMaxLenParameter_CleansToSingleLineAndTruncates()
+    {
+        var input = "<p>First line</p>\n\n<p>Second line with a lot of details here.</p>";
+        var result = _converter.Convert(input, typeof(string), 25, CultureInfo.InvariantCulture);
+
+        Assert.Equal("First line Second line...", result);
+    }
+
+    /// <summary>
+    /// Verifies Convert with string parameter parses integer and truncates.
+    /// </summary>
+    [Fact]
+    public void Convert_WithStringParameter_ParsesAndTruncates()
+    {
+        var input = "<p>First line</p>\n\n<p>Second line with a lot of details here.</p>";
+        var result = _converter.Convert(input, typeof(string), "25", CultureInfo.InvariantCulture);
+
+        Assert.Equal("First line Second line...", result);
+    }
+
+    /// <summary>
+    /// Verifies Convert handles non-string input by returning value untouched.
+    /// </summary>
+    [Fact]
+    public void Convert_WithScriptAndStyleTags_StripsContents()
+    {
+        var input = "<style>.hide { display: none; }</style><p>Hello World</p><script>alert('bad');</script>";
+        var result = _converter.Convert(input, typeof(string), null, CultureInfo.InvariantCulture);
+
+        Assert.Equal("Hello World", result);
+    }
+
+    /// <summary>
+    /// Verifies Convert handles non-string input by returning value untouched.
+    /// </summary>
+    [Fact]
+    public void Convert_NonStringValue_ReturnsOriginalValue()
+    {
+        var result = _converter.Convert(42, typeof(int), null, CultureInfo.InvariantCulture);
+        Assert.Equal(42, result);
+    }
+
+    /// <summary>
+    /// Verifies ConvertBack throws NotSupportedException.
+    /// </summary>
+    [Fact]
+    public void ConvertBack_ThrowsNotSupportedException()
+    {
+        Assert.Throws<NotSupportedException>(() =>
+            _converter.ConvertBack("test", typeof(string), null, CultureInfo.InvariantCulture));
+    }
+}