Add localization (#1482)

Co-authored-by: Tyrrrz <1935960+Tyrrrz@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

DiscordChatExporter.Gui/Converters/MarkdownToInlinesConverter.cs

@@ -0,0 +1,176 @@
+using System;
+using System.Globalization;
+using System.Linq;
+using Avalonia.Controls.Documents;
+using Avalonia.Data.Converters;
+using Avalonia.Layout;
+using Avalonia.Media;
+using DiscordChatExporter.Gui.Utils.Extensions;
+using DiscordChatExporter.Gui.Views.Controls;
+using Markdig;
+using Markdig.Syntax;
+using Markdig.Syntax.Inlines;
+using MarkdownInline = Markdig.Syntax.Inlines.Inline;
+
+namespace DiscordChatExporter.Gui.Converters;
+
+public class MarkdownToInlinesConverter : IValueConverter
+{
+    public static readonly MarkdownToInlinesConverter Instance = new();
+
+    private static readonly MarkdownPipeline MarkdownPipeline = new MarkdownPipelineBuilder()
+        .UseEmphasisExtras()
+        .Build();
+
+    private static void ProcessInline(
+        InlineCollection inlines,
+        MarkdownInline markdownInline,
+        FontWeight? fontWeight = null,
+        FontStyle? fontStyle = null,
+        TextDecorationCollection? textDecorations = null
+    )
+    {
+        switch (markdownInline)
+        {
+            case LiteralInline literal:
+            {
+                var run = new Run(literal.Content.ToString());
+
+                if (fontWeight is not null)
+                    run.FontWeight = fontWeight.Value;
+                if (fontStyle is not null)
+                    run.FontStyle = fontStyle.Value;
+                if (textDecorations is not null)
+                    run.TextDecorations = textDecorations;
+
+                inlines.Add(run);
+                break;
+            }
+
+            case LineBreakInline:
+            {
+                inlines.Add(new LineBreak());
+                break;
+            }
+
+            case EmphasisInline emphasis:
+            {
+                var newWeight = fontWeight;
+                var newStyle = fontStyle;
+                var newDecorations = textDecorations;
+
+                switch (emphasis.DelimiterChar)
+                {
+                    case '*' or '_' when emphasis.DelimiterCount == 2:
+                        newWeight = FontWeight.SemiBold;
+                        break;
+                    case '*' or '_':
+                        newStyle = FontStyle.Italic;
+                        break;
+                    case '~':
+                        newDecorations = TextDecorations.Strikethrough;
+                        break;
+                    case '+':
+                        newDecorations = TextDecorations.Underline;
+                        break;
+                }
+
+                foreach (var child in emphasis)
+                    ProcessInline(inlines, child, newWeight, newStyle, newDecorations);
+
+                break;
+            }
+
+            case LinkInline link:
+            {
+                inlines.Add(
+                    new InlineUIContainer(
+                        new HyperLink
+                        {
+                            Text = link.GetInnerText(),
+                            Url = link.Url,
+                            VerticalAlignment = VerticalAlignment.Bottom,
+                        }
+                    )
+                );
+
+                break;
+            }
+
+            case ContainerInline container:
+            {
+                foreach (var child in container)
+                    ProcessInline(inlines, child, fontWeight, fontStyle, textDecorations);
+
+                break;
+            }
+        }
+    }
+
+    public object? Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
+    {
+        var inlines = new InlineCollection();
+        if (value is not string { Length: > 0 } text)
+            return inlines;
+
+        var isFirst = true;
+
+        foreach (var block in Markdown.Parse(text, MarkdownPipeline))
+        {
+            switch (block)
+            {
+                case ParagraphBlock { Inline: not null } paragraph:
+                {
+                    if (!isFirst)
+                    {
+                        // Insert a blank line between paragraphs
+                        inlines.Add(new LineBreak());
+                        inlines.Add(new LineBreak());
+                    }
+
+                    isFirst = false;
+
+                    foreach (var markdownInline in paragraph.Inline!)
+                        ProcessInline(inlines, markdownInline);
+
+                    break;
+                }
+
+                case ListBlock list:
+                {
+                    var itemOrder = 1;
+                    if (list.IsOrdered && int.TryParse(list.OrderedStart, out var startNum))
+                        itemOrder = startNum;
+
+                    foreach (var listItem in list.OfType<ListItemBlock>())
+                    {
+                        if (!isFirst)
+                            inlines.Add(new LineBreak());
+                        isFirst = false;
+
+                        var prefix = list.IsOrdered ? $"{itemOrder++}. " : $"{list.BulletType}  ";
+                        inlines.Add(new Run(prefix));
+
+                        foreach (var subBlock in listItem.OfType<ParagraphBlock>())
+                        {
+                            if (subBlock is { Inline: not null } p)
+                                foreach (var markdownInline in p.Inline)
+                                    ProcessInline(inlines, markdownInline);
+                        }
+                    }
+
+                    break;
+                }
+            }
+        }
+
+        return inlines;
+    }
+
+    public object? ConvertBack(
+        object? value,
+        Type targetType,
+        object? parameter,
+        CultureInfo culture
+    ) => throw new NotSupportedException();
+}