Fix standard emoji not rendering as Discord-style images (#1488)

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

DiscordChatExporter.Core/Discord/Data/EmojiIndex.cs

@@ -8855,6 +8855,8 @@ internal static class EmojiIndex
         ["united_nations"] = "🇺🇳",
     };
 
+    public static IReadOnlyCollection<string> GetAllNames() => _toCodes.Keys;
+
     public static string? TryGetCode(string name) => _toCodes.GetValueOrDefault(name);
 
     public static string? TryGetName(string code) => _fromCodes.GetValueOrDefault(code);

DiscordChatExporter.Core/Markdown/Parsing/MarkdownParser.cs

@@ -208,53 +208,18 @@ internal static partial class MarkdownParser
     private static readonly IMatcher<MarkdownContext, MarkdownNode> StandardEmojiNodeMatcher =
         new RegexMatcher<MarkdownContext, MarkdownNode>(
             new Regex(
-                @"("
+                // Build a pattern from all known emoji, sorted longest-first so that compound
-                    +
+                // emoji (e.g. sequences with ZWJ or skin-tone modifiers) are matched before
-                    // Country flag emoji (two regional indicator surrogate pairs)
+                // their individual components.
-                    @"(?:\uD83C[\uDDE6-\uDDFF]){2}|"
+                "("
-                    +
+                    + string.Join(
-                    // Digit emoji (digit followed by enclosing mark)
+                        "|",
-                    @"\d\p{Me}|"
+                        EmojiIndex
-                    +
+                            .GetAllNames()
-                    // Surrogate pair
+                            .OrderByDescending(e => e.Length)
-                    @"\p{Cs}{2}|"
+                            .Select(Regex.Escape)
-                    +
+                    )
-                    // Miscellaneous characters
+                    + ")",
-                    @"["
-                    + @"\u2600-\u2604"
-                    + @"\u260E\u2611"
-                    + @"\u2614-\u2615"
-                    + @"\u2618\u261D\u2620"
-                    + @"\u2622-\u2623"
-                    + @"\u2626\u262A"
-                    + @"\u262E-\u262F"
-                    + @"\u2638-\u263A"
-                    + @"\u2640\u2642"
-                    + @"\u2648-\u2653"
-                    + @"\u265F-\u2660"
-                    + @"\u2663"
-                    + @"\u2665-\u2666"
-                    + @"\u2668\u267B"
-                    + @"\u267E-\u267F"
-                    + @"\u2692-\u2697"
-                    + @"\u2699"
-                    + @"\u269B-\u269C"
-                    + @"\u26A0-\u26A1"
-                    + @"\u26A7"
-                    + @"\u26AA-\u26AB"
-                    + @"\u26B0-\u26B1"
-                    + @"\u26BD-\u26BE"
-                    + @"\u26C4-\u26C5"
-                    + @"\u26C8"
-                    + @"\u26CE-\u26CF"
-                    + @"\u26D1"
-                    + @"\u26D3-\u26D4"
-                    + @"\u26E9-\u26EA"
-                    + @"\u26F0-\u26F5"
-                    + @"\u26F7-\u26FA"
-                    + @"\u26FD"
-                    + @"]"
-                    + @")",
                 DefaultRegexOptions
             ),
             (_, _, m) => new EmojiNode(m.Groups[1].Value)