From 3d921cbcece6c29736fe626f2ad1ae2cf4b0f26d Mon Sep 17 00:00:00 2001
From: MathMan05 <mathmanrm@gmail.com>
Date: Tue, 3 Feb 2026 15:54:28 -0600
Subject: [PATCH] send message to join thread

---
 .../channels/#channel_id/messages/index.ts    | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/src/api/routes/channels/#channel_id/messages/index.ts b/src/api/routes/channels/#channel_id/messages/index.ts
index 7f8b4b955..a5913e52c 100644
--- a/src/api/routes/channels/#channel_id/messages/index.ts
+++ b/src/api/routes/channels/#channel_id/messages/index.ts
@@ -42,6 +42,10 @@ import {
     uploadFile,
     User,
     Recipient,
+    ThreadMember,
+    ThreadMemberFlags,
+    ThreadMembersUpdateEvent,
+    ThreadCreateEvent,
 } from "@spacebar/util";
 import { Request, Response, Router } from "express";
 import { HTTPError } from "lambert-server";
@@ -315,6 +319,7 @@ router.post(
     },
     route({
         requestBody: "MessageCreateSchema",
+        permission: "VIEW_CHANNEL",
         right: "SEND_MESSAGES",
         responses: {
             200: {
@@ -338,6 +343,43 @@ router.post(
         });
         if (channel.isThread()) {
             req.permission!.hasThrow("SEND_MESSAGES_IN_THREADS");
+            if (channel.recipients && !channel.recipients.find(({ id }) => id === req.user_id)) {
+                const member = await Member.findOneOrFail({ where: { id: req.user_id, guild_id: channel.guild_id! } });
+
+                if (!(await ThreadMember.existsBy({ member_idx: member.index, id: channel_id }))) {
+                    const threadMember = ThreadMember.create({
+                        member_idx: member.index,
+                        id: channel_id,
+                        join_timestamp: new Date(),
+                        muted: false,
+                        flags: ThreadMemberFlags.ALL_MESSAGES,
+                    });
+                    await threadMember.save();
+
+                    // increment member count
+                    if (channel.member_count !== null && channel.member_count !== undefined) {
+                        channel.member_count++;
+                        await channel.save();
+                    }
+
+                    await emitEvent({
+                        event: "THREAD_MEMBERS_UPDATE",
+                        data: {
+                            guild_id: channel.guild_id!,
+                            id: channel.id,
+                            member_count: channel.member_count,
+                            added_members: [{ user_id: req.user_id, ...threadMember.toJSON() }],
+                        },
+                        channel_id: channel.id,
+                    } as ThreadMembersUpdateEvent);
+
+                    await emitEvent({
+                        event: "THREAD_CREATE",
+                        data: { ...channel.toJSON(), newly_created: false },
+                        user_id: req.user_id,
+                    } as ThreadCreateEvent);
+                }
+            }
         } else {
             req.permission!.hasThrow("SEND_MESSAGES");
         }