From 910576921b6ae043d5afcd2c7a4302e8fbf61e91 Mon Sep 17 00:00:00 2001
From: jjbrunton <jamie@jbrunton.co.uk>
Date: Sun, 9 Aug 2026 16:22:48 +0100
Subject: [PATCH] Allow replies during room creation cooldowns

---
 src/services/chat/service.ts        | 27 +++++++++++++++++++++------
 src/services/chat/types.ts          |  5 +++++
 tests/chat-service-cooldown.test.ts | 29 +++++++++++++++++++++++++++++
 3 files changed, 55 insertions(+), 6 deletions(-)

diff --git a/src/services/chat/service.ts b/src/services/chat/service.ts
index 2c0a3a8..d1dc546 100644
--- a/src/services/chat/service.ts
+++ b/src/services/chat/service.ts
@@ -582,7 +582,7 @@ export class ChatService {
   async sendChatMessage(chatUrlOrRoomId: string, message: string): Promise<boolean> {
     if (!this.accountAuth?.isFullyAuthenticated()) return false;
     const active = this.getInvitationCooldown();
-    if (active) {
+    if (active && this.blocksExistingRoomSends(active)) {
       const secondsLeft = Math.ceil((active.until - Date.now()) / 1000);
       this.logger.warn(
         `[chat] skipping sendChatMessage — send cooldown active for ${secondsLeft}s (${active.redditCode ?? 'rate-limited'})`,
@@ -607,7 +607,7 @@ export class ChatService {
         return true;
       } catch (error) {
         if (error instanceof MatrixRateLimitError) {
-          this.setInvitationCooldown(error);
+          this.setInvitationCooldown(error, 'all-sends');
           return false;
         }
         this.logger.error('[chat] sendChatMessage failed:', error);
@@ -690,7 +690,7 @@ export class ChatService {
         return { status: 'sent', chat };
       } catch (error) {
         if (error instanceof MatrixRateLimitError) {
-          this.setInvitationCooldown(error);
+          this.setInvitationCooldown(error, 'room-creation');
           const cooldown = this.getInvitationCooldown();
           return {
             status: 'retryable',
@@ -758,17 +758,21 @@ export class ChatService {
   }
 
   /** Record a cooldown after a `MatrixRateLimitError`. Test seam + reuse. */
-  setInvitationCooldown(error: MatrixRateLimitError): void {
+  setInvitationCooldown(
+    error: MatrixRateLimitError,
+    scope: NonNullable<InvitationCooldown['scope']> = this.inferCooldownScope(error.redditCode),
+  ): void {
     const now = Date.now();
     // Add a small safety margin so we don't probe again the very second
     // the homeserver thinks the window expired.
     const margin = 5_000;
     this.invitationCooldown = {
       until: now + error.retryAfterMs + margin,
+      scope,
       redditCode: error.redditCode,
       reason:
-        error.redditCode === 'rate.invitation_limit_mature_account'
-          ? "Reddit is throttling new chat invitations (\"you've created a lot of chats, take a break\")."
+        scope === 'room-creation'
+          ? 'Reddit is throttling new chat invitations; replies in existing chats can continue.'
           : `Matrix rate-limited: ${error.errcode ?? '429'}`,
       setAt: now,
     };
@@ -780,6 +784,17 @@ export class ChatService {
     void this.cache.persistCooldown();
   }
 
+  private blocksExistingRoomSends(cooldown: InvitationCooldown): boolean {
+    return (cooldown.scope ?? this.inferCooldownScope(cooldown.redditCode)) === 'all-sends';
+  }
+
+  private inferCooldownScope(redditCode: string | null): NonNullable<InvitationCooldown['scope']> {
+    return redditCode === 'rate.room_creation_limit'
+      || redditCode === 'rate.invitation_limit_mature_account'
+      ? 'room-creation'
+      : 'all-sends';
+  }
+
   // ------------ internals ------------
 
   /** Single delta /sync that updates cache + nextBatch and returns the union. */
diff --git a/src/services/chat/types.ts b/src/services/chat/types.ts
index 5c6a607..d550af8 100644
--- a/src/services/chat/types.ts
+++ b/src/services/chat/types.ts
@@ -37,6 +37,11 @@ export interface ActiveChat {
 export interface InvitationCooldown {
   /** Wall-clock ms when sends may resume. */
   until: number;
+  /**
+   * Operation class affected by the homeserver limit. Optional for caches
+   * written before cooldowns distinguished new rooms from existing-room sends.
+   */
+  scope?: 'room-creation' | 'all-sends';
   /** Reddit-side error code, e.g. `rate.invitation_limit_mature_account`. */
   redditCode: string | null;
   /** Human-readable explanation suitable for the dashboard. */
diff --git a/tests/chat-service-cooldown.test.ts b/tests/chat-service-cooldown.test.ts
index 354d045..042b3d0 100644
--- a/tests/chat-service-cooldown.test.ts
+++ b/tests/chat-service-cooldown.test.ts
@@ -115,6 +115,35 @@ describe('ChatService invitation cooldown', () => {
     expect(result).toBe(false);
   });
 
+  it('allows replies in existing rooms during a room-creation cooldown', async () => {
+    const { svc, matrix } = buildService();
+    matrix.sendTextMessage = async () => '$reply';
+    svc.setInvitationCooldown(
+      new MatrixRateLimitError(
+        '429',
+        60_000,
+        'M_LIMIT_EXCEEDED',
+        'rate.room_creation_limit',
+      ),
+    );
+    // Simulate a cooldown persisted before operation scopes were recorded.
+    delete svc.getInvitationCooldown()!.scope;
+
+    await expect(svc.sendChatMessage('!room:example.test', 'hi')).resolves.toBe(true);
+  });
+
+  it('treats a generic limit raised while creating a room as room-creation-only', async () => {
+    const { svc, matrix } = buildService();
+    matrix.sendInitialDirectMessage = async () => {
+      throw new MatrixRateLimitError('429', 60_000, 'M_LIMIT_EXCEEDED', null);
+    };
+    matrix.sendTextMessage = async () => '$reply';
+
+    await expect(svc.startConversationDetailed('someuser', 'opener', 't2_someuser'))
+      .resolves.toMatchObject({ status: 'retryable' });
+    await expect(svc.sendChatMessage('!room:example.test', 'reply')).resolves.toBe(true);
+  });
+
   it('persists the cooldown to disk and restores it after a fresh service load', async () => {
     const logger = createMockLogger();
     const tmpDir = await fs.mkdtemp(path.join(os.tmpdir(), 'chat-cooldown-'));