fix(blog,stores): redirect old blog slugs to the post they meant; hide expired deals

apps/web/app/api/stores/[slug]/route.ts

@@ -12,6 +12,7 @@ export async function GET(_req: NextRequest, { params }: { params: Promise<{ slu
     const store = stores[0];
     const coupons = await db.sql`
       SELECT * FROM coupons WHERE store_id = ${store.id}
+        AND (expiry_date IS NULL OR expiry_date = '' OR expiry_date >= date('now'))
       ORDER BY votes DESC, created_at DESC
     `;
     return NextResponse.json({ store, coupons });

apps/web/app/blog/[slug]/page.tsx

@@ -1,10 +1,11 @@
 export const dynamic = 'force-dynamic';
 
 import type { Metadata } from 'next';
-import { notFound } from 'next/navigation';
+import { notFound, permanentRedirect } from 'next/navigation';
 import Image from 'next/image';
 import Link from 'next/link';
 import { getDb } from '@/lib/db';
+import { closestSlug } from '@/lib/blog-slugs';
 import { sanitizeBlogHtml } from '@/lib/sanitize-blog-html';
 
 interface Post {
@@ -35,6 +36,16 @@ async function getPost(slug: string): Promise<Post | null> {
   }
 }
 
+async function publishedSlugs(): Promise<string[]> {
+  try {
+    const rows = await getDb().sql`SELECT slug FROM blog_posts WHERE status = 'published'`;
+    return rows.map((r: { slug: string }) => r.slug);
+  } catch (error) {
+    console.error('[blog] failed to list slugs', error);
+    return [];
+  }
+}
+
 export async function generateMetadata({ params }: { params: Promise<{ slug: string }> }): Promise<Metadata> {
   const { slug } = await params;
   const post = await getPost(slug);
@@ -61,7 +72,13 @@ export async function generateMetadata({ params }: { params: Promise<{ slug: str
 export default async function BlogPostPage({ params }: { params: Promise<{ slug: string }> }) {
   const { slug } = await params;
   const post = await getPost(slug);
-  if (!post) notFound();
+  if (!post) {
+    // An old slug goes to the post it meant (308), else the blog index.
+    const meant = closestSlug(slug, await publishedSlugs());
+    if (meant && meant !== slug) permanentRedirect(`/blog/${meant}`);
+    if (/^[a-z0-9-]+$/.test(slug)) permanentRedirect('/blog');
+    notFound();
+  }
   const sanitizedContent = sanitizeBlogHtml(post.content);
 
   return (

apps/web/app/stores/[slug]/page.tsx

@@ -18,6 +18,7 @@ const getStore = cache(async (slug: string): Promise<{ store: Store; coupons: Co
     const store = stores[0];
     const coupons = await db.sql`
       SELECT * FROM coupons WHERE store_id = ${store.id}
+        AND (expiry_date IS NULL OR expiry_date = '' OR expiry_date >= date('now'))
       ORDER BY votes DESC, created_at DESC
     `;
     return { store, coupons };

apps/web/lib/blog-slugs.ts

@@ -0,0 +1,44 @@
+/** Levenshtein distance, stopping early once it exceeds `max`. */
+export function editDistance(a: string, b: string, max = Infinity): number {
+  if (Math.abs(a.length - b.length) > max) return max + 1;
+  let prev = Array.from({ length: b.length + 1 }, (_, j) => j);
+  for (let i = 1; i <= a.length; i++) {
+    const cur = [i];
+    let best = i;
+    for (let j = 1; j <= b.length; j++) {
+      cur[j] = Math.min(prev[j] + 1, cur[j - 1] + 1, prev[j - 1] + (a[i - 1] === b[j - 1] ? 0 : 1));
+      best = Math.min(best, cur[j]);
+    }
+    if (best > max) return max + 1;
+    prev = cur;
+  }
+  return prev[b.length];
+}
+
+/** Store-name token: the first dash-separated word ("doordash-promo-..." -> "doordash"). */
+const lead = (s: string) => s.split('-')[0];
+
+/**
+ * The published slug an old or mistyped one meant: the closest by edit distance
+ * within a third of its length; failing that, the only slug sharing the leading
+ * store name (doordash-..., shutterfly-..., walgreens-...), else the shortest
+ * edit distance among those sharing it. Null when nothing plausible exists.
+ */
+export function closestSlug(slug: string, slugs: Iterable<string>): string | null {
+  const all = [...slugs];
+  if (all.includes(slug)) return slug;
+  const max = Math.max(3, Math.floor(slug.length / 3));
+  let best: string | null = null;
+  let bestD = max + 1;
+  for (const s of all) {
+    const d = editDistance(slug, s, bestD - 1);
+    if (d < bestD) {
+      best = s;
+      bestD = d;
+    }
+  }
+  if (best) return best;
+  const sameStore = all.filter((s) => lead(s) === lead(slug) && lead(slug).length >= 4);
+  if (!sameStore.length) return null;
+  return sameStore.sort((a, b) => editDistance(slug, a) - editDistance(slug, b))[0];
+}

test/blog-slugs.test.mjs

@@ -0,0 +1,20 @@
+import { describe, expect, it } from 'bun:test';
+import { closestSlug } from '../apps/web/lib/blog-slugs.ts';
+
+const SLUGS = [
+  'amazon-promo-code-workflow',
+  'cvs-photo-promo-code-workflow',
+  'walgreens-photo-coupon-code-workflow-2026',
+  'walgreens-photo-coupon-code-workflow-2026-guide',
+  'papa-johns-promo-codes-2026-checkout-workflow',
+];
+describe('closestSlug', () => {
+  it('maps an old slug to the post of the same store', () => {
+    expect(closestSlug('walgreens-coupon-code-workflow', SLUGS)).toBe('walgreens-photo-coupon-code-workflow-2026');
+  });
+  it('keeps an existing slug and returns null when no post is close', () => {
+    expect(closestSlug('cvs-photo-promo-code-workflow', SLUGS)).toBe('cvs-photo-promo-code-workflow');
+    expect(closestSlug('doordash-promo-codes-for-existing-users-2026-workflow', SLUGS)).toBeNull();
+    expect(closestSlug('encrypted-messaging-coupon-codes-private-deal-sharing', SLUGS)).toBeNull();
+  });
+});