Improve seller account filtering

src/reddit/api.ts

@@ -48,6 +48,38 @@ export interface RedditPost {
   link_flair_text?: string | null;
 }
 
+interface RedditListingChild {
+  data?: {
+    title?: unknown;
+    selftext?: unknown;
+    body?: unknown;
+    url?: unknown;
+    subreddit?: unknown;
+  };
+}
+
+function joinText(values: unknown[]): string {
+  return values.filter((value): value is string => typeof value === 'string').join(' ');
+}
+
+/** Match configured seller signals in user-controlled text. */
+export function findSellerSignal(
+  text: string,
+  keywords: string[],
+  domains: string[],
+): { kind: 'keyword' | 'domain'; value: string } | null {
+  const normalized = text.toLocaleLowerCase();
+  for (const keyword of keywords) {
+    const candidate = keyword.trim().toLocaleLowerCase();
+    if (candidate && normalized.includes(candidate)) {
+      return { kind: 'keyword', value: keyword };
+    }
+  }
+
+  const domain = findSellerDomain(text, domains);
+  return domain ? { kind: 'domain', value: domain } : null;
+}
+
 // Extracts URL-ish tokens (with or without scheme) and returns the first
 // domain match. Matches `host` or any subdomain (`*.host`), case-insensitive.
 export function findSellerDomain(text: string, domains: string[]): string | null {
@@ -249,10 +281,28 @@ export class RedditApiClient {
   async isSellerProfile(
     username: string,
     sellerKeywords: string[],
-    sellerDomains: string[] = []
+    sellerDomains: string[] = [],
+    currentPost?: RedditPost,
   ): Promise<boolean> {
     if (sellerKeywords.length === 0 && sellerDomains.length === 0) return false;
 
+    // Check the post first. This catches direct promotional posts without an
+    // extra request and also covers accounts whose profile bio is deliberately
+    // vague.
+    if (currentPost) {
+      const postSignal = findSellerSignal(
+        joinText([currentPost.title, currentPost.selftext, currentPost.url]),
+        sellerKeywords,
+        sellerDomains,
+      );
+      if (postSignal) {
+        this.logger.info(
+          `u/${username} flagged as seller from current post (matched ${postSignal.kind}: "${postSignal.value}")`,
+        );
+        return true;
+      }
+    }
+
     try {
       const cookieHeader = await this.getCookieHeader();
       const headers: Record<string, string> = {};
@@ -260,51 +310,67 @@ export class RedditApiClient {
         headers['Cookie'] = cookieHeader;
       }
 
-      const response = await this.client.get(`/user/${username}/about.json`, {
+      const response = await this.client.get(`/user/${encodeURIComponent(username)}/about.json`, {
         params: { raw_json: 1 },
         headers,
       });
 
       const userData = response.data?.data;
-      if (!userData) return false;
-
-      // Combine all text fields to scan
-      const textToCheck = [
-        userData.subreddit?.public_description || '',
-        userData.subreddit?.title || '',
-        userData.subreddit?.display_name_prefixed || '',
-      ]
-        .join(' ')
-        .toLowerCase();
-
-      for (const keyword of sellerKeywords) {
-        if (textToCheck.includes(keyword.toLowerCase())) {
+      if (userData) {
+        const profileText = joinText([
+          userData.subreddit?.public_description || '',
+          userData.subreddit?.title || '',
+          userData.subreddit?.display_name_prefixed || '',
+        ]);
+        const profileSignal = findSellerSignal(profileText, sellerKeywords, sellerDomains);
+        if (profileSignal) {
           this.logger.info(
-            `u/${username} flagged as seller profile (matched keyword: "${keyword}")`
+            `u/${username} flagged as seller profile (matched ${profileSignal.kind}: "${profileSignal.value}")`,
           );
           return true;
         }
       }
-
-      if (sellerDomains.length > 0) {
-        const matchedDomain = findSellerDomain(textToCheck, sellerDomains);
-        if (matchedDomain) {
-          this.logger.info(
-            `u/${username} flagged as seller profile (matched domain: "${matchedDomain}")`
-          );
-          return true;
-        }
-      }
-
-      return false;
     } catch (error) {
       if (axios.isAxiosError(error) && error.response?.status === 404) {
         this.logger.warn(`User u/${username} profile not found`);
         return false;
       }
       this.logger.warn(`Failed to check profile for u/${username}:`, error);
-      return false; // Don't block on errors - let it through
     }
+
+    // Bios are often clean while recent posts advertise the paid account.
+    // Scan a small overview page, including comment bodies and subreddit
+    // names, before allowing the candidate through.
+    try {
+      const cookieHeader = await this.getCookieHeader();
+      const headers: Record<string, string> = {};
+      if (cookieHeader) headers.Cookie = cookieHeader;
+      const response = await this.client.get(`/user/${encodeURIComponent(username)}/overview.json`, {
+        params: { limit: 25, raw_json: 1 },
+        headers,
+      });
+      const children: RedditListingChild[] = Array.isArray(response.data?.data?.children)
+        ? response.data.data.children
+        : [];
+      const activityText = children.map(({ data }) => joinText([
+        data?.title,
+        data?.selftext,
+        data?.body,
+        data?.url,
+        data?.subreddit,
+      ])).join(' ');
+      const activitySignal = findSellerSignal(activityText, sellerKeywords, sellerDomains);
+      if (activitySignal) {
+        this.logger.info(
+          `u/${username} flagged as seller from recent activity (matched ${activitySignal.kind}: "${activitySignal.value}")`,
+        );
+        return true;
+      }
+    } catch (error) {
+      this.logger.warn(`Failed to check recent activity for u/${username}:`, error);
+    }
+
+    return false; // Fail open if Reddit profile endpoints are unavailable.
   }
 
   getPostUrl(post: RedditPost): string {