Refactor

DiscordChatExporter.Core/Discord/Dump/DataDump.cs

@@ -0,0 +1,60 @@
+using System;
+using System.Collections.Generic;
+using System.IO.Compression;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Core.Discord.Dump;
+
+public partial class DataDump
+{
+    public IReadOnlyList<DataDumpChannel> Channels { get; }
+
+    public DataDump(IReadOnlyList<DataDumpChannel> channels) => Channels = channels;
+}
+
+public partial class DataDump
+{
+    public static DataDump Parse(JsonElement json)
+    {
+        var channels = new List<DataDumpChannel>();
+
+        foreach (var property in json.EnumerateObjectOrEmpty())
+        {
+            var channelId = Snowflake.Parse(property.Name);
+            var channelName = property.Value.GetString();
+
+            // Null items refer to deleted channels
+            if (channelName is null)
+                continue;
+
+            var channel = new DataDumpChannel(channelId, channelName);
+            channels.Add(channel);
+        }
+
+        return new DataDump(channels);
+    }
+
+    public static async ValueTask<DataDump> LoadAsync(
+        string zipFilePath,
+        CancellationToken cancellationToken = default
+    )
+    {
+        using var archive = ZipFile.OpenRead(zipFilePath);
+
+        var entry = archive.GetEntry("messages/index.json");
+        if (entry is null)
+        {
+            throw new InvalidOperationException(
+                "Could not find the channel index inside the data package."
+            );
+        }
+
+        await using var stream = entry.Open();
+        using var document = await JsonDocument.ParseAsync(stream, default, cancellationToken);
+
+        return Parse(document.RootElement);
+    }
+}

DiscordChatExporter.Core/Discord/Dump/DataDumpChannel.cs

@@ -0,0 +1,3 @@
+namespace DiscordChatExporter.Core.Discord.Dump;
+
+public record DataDumpChannel(Snowflake Id, string Name);