Preliminary support for threads (#1032)

DiscordChatExporter.Core/Discord/Data/ThreadChannel.cs

@@ -0,0 +1,50 @@
+using System.Linq;
+using System.Text.Json;
+using DiscordChatExporter.Core.Discord.Data.Common;
+using DiscordChatExporter.Core.Utils.Extensions;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/channel#channel-object-example-thread-channel
+public partial record ThreadChannel(
+    Snowflake Id,
+    ChannelKind Kind,
+    Snowflake GuildId,
+    string Name,
+    Snowflake? LastMessageId) : IHasId
+{
+
+}
+
+public partial record ThreadChannel
+{
+    public static ThreadChannel Parse(JsonElement json)
+    {
+        var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
+        var kind = (ChannelKind)json.GetProperty("type").GetInt32();
+
+        var guildId =
+            json.GetPropertyOrNull("guild_id")?.GetNonWhiteSpaceStringOrNull()?.Pipe(Snowflake.Parse) ?? default;
+
+        var name =
+            // Guild channel
+            json.GetPropertyOrNull("name")?.GetNonWhiteSpaceStringOrNull() ??
+
+            // Fallback
+            id.ToString();
+
+        var lastMessageId = json
+            .GetPropertyOrNull("last_message_id")?
+            .GetNonWhiteSpaceStringOrNull()?
+            .Pipe(Snowflake.Parse);
+
+        return new ThreadChannel(
+            id,
+            kind,
+            guildId,
+            name,
+            lastMessageId
+        );
+    }
+}

DiscordChatExporter.Core/Discord/DiscordClient.cs

@@ -200,6 +200,35 @@ public class DiscordClient
         return Guild.Parse(response);
     }
 
+    public async IAsyncEnumerable<ThreadChannel> GetGuildChannelThreadsAsync(
+        string channelId,
+        [EnumeratorCancellation] CancellationToken cancellationToken = default)
+    {
+        int currentOffset = 0;
+
+        while (true)
+        {
+            var url = new UrlBuilder()
+                .SetPath($"channels/{channelId}/threads/search")
+                .SetQueryParameter("offset", currentOffset.ToString())
+                .Build();
+
+            var response = await TryGetJsonResponseAsync(url, cancellationToken);
+
+            if (response is null)
+                break;
+
+            foreach (var threadJson in response.Value.GetProperty("threads").EnumerateArray())
+                yield return ThreadChannel.Parse(threadJson);
+
+            if (!response.Value.GetProperty("has_more").GetBoolean())
+            {
+                break;
+            }
+                currentOffset += response.Value.GetProperty("threads").GetArrayLength();
+        }
+    }
+
     public async IAsyncEnumerable<Channel> GetGuildChannelsAsync(
         Snowflake guildId,
         [EnumeratorCancellation] CancellationToken cancellationToken = default)