add TG skill

bot/src/util/flood-wait.ts

@@ -0,0 +1,60 @@
+import { childLogger } from "./logger.js";
+
+const log = childLogger("flood-wait");
+
+function sleep(ms: number): Promise<void> {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
+
+/**
+ * Extract the mandatory wait duration (in seconds) from a Telegram
+ * FLOOD_WAIT error. Returns null when the error is not rate-limit related.
+ */
+export function extractFloodWaitSeconds(err: unknown): number | null {
+  const message = err instanceof Error ? err.message : String(err);
+
+  // Pattern 1: FLOOD_WAIT_30
+  const flood = message.match(/FLOOD_WAIT_(\d+)/i);
+  if (flood) return parseInt(flood[1], 10);
+
+  // Pattern 2: "retry after 30"
+  const retry = message.match(/retry after (\d+)/i);
+  if (retry) return parseInt(retry[1], 10);
+
+  // Pattern 3: HTTP 429 without explicit seconds
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  if (String((err as any)?.code) === "429") return 30;
+
+  return null;
+}
+
+/**
+ * Wrap any async Telegram operation with automatic FLOOD_WAIT retry.
+ * Adds random jitter (1-5s) to prevent thundering-herd retries.
+ *
+ * Non-rate-limit errors are re-thrown immediately (fail-fast).
+ */
+export async function withFloodWait<T>(
+  fn: () => Promise<T>,
+  context?: string,
+  maxRetries = 5
+): Promise<T> {
+  for (let attempt = 0; attempt <= maxRetries; attempt++) {
+    try {
+      return await fn();
+    } catch (err) {
+      const wait = extractFloodWaitSeconds(err);
+      if (wait === null || attempt >= maxRetries) throw err;
+
+      const jitter = 1000 + Math.random() * 4000;
+      log.warn(
+        { context, wait, attempt: attempt + 1, maxRetries, jitter: Math.round(jitter) },
+        "FLOOD_WAIT received — backing off"
+      );
+      await sleep(wait * 1000 + jitter);
+    }
+  }
+  throw new Error("Unreachable");
+}
+
+export { sleep };