Add /walkthrough command. (#6)

Author: phorcys420

lib/discord/interactions/commands/commands.dart

@@ -3,6 +3,7 @@ import "package:codercord/discord/client.dart" show logger;
 import "tag.dart" as command_tag;
 import "close.dart" as command_close;
 import "reopen.dart" as command_reopen;
+import "walkthrough.dart" as command_walkthrough;
 
 import "package:nyxx_interactions/nyxx_interactions.dart";
 
@@ -11,6 +12,7 @@ Future<List<SlashCommandBuilder>> getSlashCommands() async {
     command_tag.getCommand(await command_tag.getTags()),
     command_close.getCommand(),
     command_reopen.getCommand(),
+    command_walkthrough.getCommand()
   ];
 }
 

lib/discord/interactions/commands/walkthrough.dart

@@ -0,0 +1,51 @@
+import "package:codercord/discord/components/category_multi_select.dart";
+import "package:codercord/discord/interactions/commands/close.dart";
+import "package:codercord/discord/utils.dart";
+import "package:codercord/values.dart";
+
+import "package:nyxx/nyxx.dart";
+
+import "package:nyxx_interactions/nyxx_interactions.dart";
+
+SlashCommandBuilder getCommand() {
+  return SlashCommandBuilder(
+    "walkthrough",
+    "Sends the walkthrough message in case the bot didn't send it",
+    [],
+    guild: coderServer.id,
+    canBeUsedInDm: false,
+  )..registerHandler((p0) async {
+      final interactionChannel = await p0.interaction.channel.getOrDownload();
+
+      if (interactionChannel.channelType == ChannelType.guildPublicThread) {
+        final threadChannel = interactionChannel as IThreadChannel;
+
+        if (await threadChannel.isHelpPost) {
+          if (threadChannel.appliedTags.isEmpty) {
+            await threadChannel.setPostTags([openedTagID]);
+          }
+
+          final channelMessages = threadChannel.downloadMessages(
+            limit: 10,
+            around: Snowflake.fromDateTime(threadChannel.createdAt),
+          );
+
+          try {
+            IMessage walkthroughMessage = await channelMessages.firstWhere(
+              (message) =>
+                  message.author.id == (p0.client as INyxxWebsocket).self.id &&
+                  (message.components.isNotEmpty || message.embeds.isNotEmpty),
+            );
+
+            await p0.respond(
+                MessageBuilder.content(
+                  "You cannot run the walkthrough again because a walkthrough already exists in this channel\n(${walkthroughMessage.url})",
+                ),
+                hidden: true);
+          } on StateError catch (_) {
+            p0.respond(categoryMultiSelectMessage);
+          }
+        }
+      }
+    });
+}