From 59b539eb84b04990a1e03e0b061541e74ea03bd7 Mon Sep 17 00:00:00 2001
From: Makar Dzhehur <makardzhehur2@gmail.com>
Date: Mon, 29 Jun 2026 08:41:45 +0300
Subject: [PATCH] fix(bot): re-exchange tokens on 401 instead of rotating
 refresh

---
 apps/bot/src/services/apiClient.ts  | 89 ++++++++++++++++-------------
 apps/bot/src/services/tokenStore.ts | 13 +++--
 2 files changed, 57 insertions(+), 45 deletions(-)

diff --git a/apps/bot/src/services/apiClient.ts b/apps/bot/src/services/apiClient.ts
index 67b1788..084c3bf 100644
--- a/apps/bot/src/services/apiClient.ts
+++ b/apps/bot/src/services/apiClient.ts
@@ -9,15 +9,54 @@ import {
 
 const { API_URL } = config;
 
+const FETCH_TIMEOUT_MS = 20_000;
+
+async function timedFetch(url: string, init: RequestInit): Promise<Response> {
+  const controller = new AbortController();
+  const timer = setTimeout(() => controller.abort(), FETCH_TIMEOUT_MS);
+  try {
+    return await fetch(url, { ...init, signal: controller.signal });
+  } finally {
+    clearTimeout(timer);
+  }
+}
+
+// Bot is a trusted service client: instead of rotating refresh tokens (which
+// trips the API's reuse-detection when a response is lost to a cold start), it
+// re-exchanges telegramId + name for a fresh pair on demand.
+async function exchangeTokens(
+  telegramId: number,
+  name: string,
+): Promise<TokenPair> {
+  const res = await timedFetch(`${API_URL}/auth/telegram/exchange`, {
+    method: "POST",
+    headers: { "Content-Type": "application/json" },
+    body: JSON.stringify({
+      source: "bot",
+      telegramId: String(telegramId),
+      name,
+    }),
+  });
+
+  if (!res.ok) {
+    throw new Error(`Telegram auth failed: ${res.status}`);
+  }
+
+  const data = (await res.json()) as TokenPair;
+  await setTokens(telegramId, data, name);
+  return data;
+}
+
 async function apiFetch(
   method: string,
   path: string,
   telegramId: number,
   body?: unknown,
+  retried = false,
 ): Promise<Response> {
   const tokens = await getTokens(telegramId);
 
-  const res = await fetch(`${API_URL}${path}`, {
+  const res = await timedFetch(`${API_URL}${path}`, {
     method,
     headers: {
       "Content-Type": "application/json",
@@ -26,56 +65,24 @@ async function apiFetch(
     ...(body !== undefined ? { body: JSON.stringify(body) } : {}),
   });
 
-  if (res.status === 401 && tokens) {
-    const refreshed = await tryRefresh(telegramId, tokens.refreshToken);
-    if (refreshed) {
-      return apiFetch(method, path, telegramId, body);
+  if (res.status === 401 && tokens && !retried) {
+    try {
+      await exchangeTokens(telegramId, tokens.name);
+    } catch {
+      await deleteTokens(telegramId);
+      return res;
     }
+    return apiFetch(method, path, telegramId, body, true);
   }
 
   return res;
 }
 
-async function tryRefresh(
-  telegramId: number,
-  refreshToken: string,
-): Promise<boolean> {
-  const res = await fetch(`${API_URL}/auth/telegram/refresh`, {
-    method: "POST",
-    headers: { "Content-Type": "application/json" },
-    body: JSON.stringify({ refreshToken }),
-  });
-
-  if (!res.ok) {
-    await deleteTokens(telegramId);
-    return false;
-  }
-
-  const data = (await res.json()) as TokenPair;
-  await setTokens(telegramId, data);
-  return true;
-}
-
 export async function authenticateUser(
   telegramId: number,
   name: string,
 ): Promise<void> {
-  const res = await fetch(`${API_URL}/auth/telegram/exchange`, {
-    method: "POST",
-    headers: { "Content-Type": "application/json" },
-    body: JSON.stringify({
-      source: "bot",
-      telegramId: String(telegramId),
-      name,
-    }),
-  });
-
-  if (!res.ok) {
-    throw new Error(`Telegram auth failed: ${res.status}`);
-  }
-
-  const data = (await res.json()) as TokenPair;
-  await setTokens(telegramId, data);
+  await exchangeTokens(telegramId, name);
 }
 
 export async function isAuthenticated(telegramId: number): Promise<boolean> {
diff --git a/apps/bot/src/services/tokenStore.ts b/apps/bot/src/services/tokenStore.ts
index c2e7fa8..7d8acda 100644
--- a/apps/bot/src/services/tokenStore.ts
+++ b/apps/bot/src/services/tokenStore.ts
@@ -1,23 +1,28 @@
 import { redis } from "../lib/redis.js";
 
 export type TokenPair = { accessToken: string; refreshToken: string };
+export type StoredSession = TokenPair & { name: string };
 
 const key = (telegramId: number) => `bot:session:${telegramId}`;
 
-// 30 days TTL – token pair is refreshed on each use
+// 30 days TTL – tokens are re-exchanged on expiry, name lets us mint a fresh pair
 const TTL_SECONDS = 60 * 60 * 24 * 30;
 
-export async function getTokens(telegramId: number): Promise<TokenPair | null> {
+export async function getTokens(
+  telegramId: number,
+): Promise<StoredSession | null> {
   const raw = await redis.get(key(telegramId));
   if (!raw) return null;
-  return JSON.parse(raw) as TokenPair;
+  return JSON.parse(raw) as StoredSession;
 }
 
 export async function setTokens(
   telegramId: number,
   tokens: TokenPair,
+  name: string,
 ): Promise<void> {
-  await redis.set(key(telegramId), JSON.stringify(tokens), "EX", TTL_SECONDS);
+  const session: StoredSession = { ...tokens, name };
+  await redis.set(key(telegramId), JSON.stringify(session), "EX", TTL_SECONDS);
 }
 
 export async function deleteTokens(telegramId: number): Promise<void> {