Add option to reverse message order in exports (#1487)

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

DiscordChatExporter.Cli.Tests/Specs/HtmlContentSpecs.cs

@@ -1,7 +1,12 @@
-using System.Linq;
+using System.IO;
+using System.Linq;
 using System.Threading.Tasks;
 using AngleSharp.Dom;
+using CliFx.Infrastructure;
+using DiscordChatExporter.Cli.Commands;
 using DiscordChatExporter.Cli.Tests.Infra;
+using DiscordChatExporter.Cli.Tests.Utils;
+using DiscordChatExporter.Core.Exporting;
 using FluentAssertions;
 using Xunit;
 
@@ -44,4 +49,41 @@ public class HtmlContentSpecs
                 "Yeet"
             );
     }
+
+    [Fact]
+    public async Task I_can_export_a_channel_in_the_HTML_format_in_the_reverse_order()
+    {
+        // Arrange
+        using var file = TempFile.Create();
+
+        // Act
+        await new ExportChannelsCommand
+        {
+            Token = Secrets.DiscordToken,
+            ChannelIds = [ChannelIds.DateRangeTestCases],
+            ExportFormat = ExportFormat.HtmlDark,
+            OutputPath = file.Path,
+            Locale = "en-US",
+            IsUtcNormalizationEnabled = true,
+            IsReverseMessageOrder = true,
+        }.ExecuteAsync(new FakeConsole());
+
+        var document = Html.Parse(await File.ReadAllTextAsync(file.Path));
+        var messages = document.QuerySelectorAll("[data-message-id]").ToArray();
+
+        // Assert
+        messages
+            .Select(e => e.GetAttribute("data-message-id"))
+            .Should()
+            .Equal(
+                "885169254029213696",
+                "868505973294268457",
+                "868505969821364245",
+                "868505966528835604",
+                "868490009366396958",
+                "866732113319428096",
+                "866710679758045195",
+                "866674314627121232"
+            );
+    }
 }