Respect Reddit rate limit delays

src/reddit/api.ts

@@ -3,6 +3,26 @@ import type { BrowserContext } from 'playwright';
 import type { Config } from '../config/index.js';
 import type { Logger } from '../utils/logger.js';
 
+export class RedditRateLimitError extends Error {
+  constructor(public readonly retryAfterMs: number) {
+    const retryAfterSeconds = Math.ceil(retryAfterMs / 1000);
+    super(`Reddit API rate limit reached; retry after ${retryAfterSeconds}s`);
+    this.name = 'RedditRateLimitError';
+  }
+}
+
+function getRateLimitDelayMs(headers: unknown): number {
+  if (!headers || typeof headers !== 'object') return 60_000;
+
+  const values = headers as Record<string, unknown>;
+  const rawDelay = values['retry-after'] ?? values['x-ratelimit-reset'];
+  const seconds = typeof rawDelay === 'number' ? rawDelay : Number.parseFloat(String(rawDelay));
+
+  return Number.isFinite(seconds) && seconds >= 0
+    ? Math.ceil(seconds * 1000)
+    : 60_000;
+}
+
 export interface RedditPost {
   id: string;
   name: string; // fullname like "t3_xxxxx"
@@ -134,8 +154,10 @@ export class RedditApiClient {
           return [];
         }
         if (error.response?.status === 429) {
-          this.logger.warn(`Rate limited by Reddit, waiting...`);
-          throw error;
+          const retryAfterMs = getRateLimitDelayMs(error.response.headers);
+          const rateLimitError = new RedditRateLimitError(retryAfterMs);
+          this.logger.warn(rateLimitError.message);
+          throw rateLimitError;
         }
       }
       this.logger.error(`Error fetching posts from r/${subreddit}:`, error);