Fix category-slot matching: identity by linkUrl slug, not array position

The homepage category carousel and installments highlights matched
slot.images[i] to categoryList[i] by array index, assuming the business's
CMS upload order lines up with this site's own category sort order. It
doesn't - live data showed a laptop photo landing on "موبایل" and "لوازم
برقی" appearing on the site despite no photo ever being uploaded for it,
purely from index luck. titleFa isn't reliable either: the same laptop image
was titled "تبلت" in the CMS, contradicting its own linkUrl.

Fix: resolve each image's category from the `category` query param on its
own linkUrl (categorySlugFromLinkUrl() in slug.ts, matched against
ApiCategory.slug via the new findNodeBySlug()). The homepage carousel is now
fully slot-driven - it iterates slot.images (in the CMS's own sortOrder) and
simply omits any category with no matching image, per explicit product
direction, rather than falling back to a placeholder. Installments keeps its
curated HIGHLIGHT_IDS list with a placeholder for uncovered categories,
since that page always shows the same fixed set, but now uses the same
identity-based lookup instead of position.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app/installments/page.tsx

@@ -5,8 +5,8 @@ import Breadcrumbs from "@/components/Breadcrumbs";
 import TrustBadges from "@/components/ui/TrustBadges";
 import { ChevronLeft, LockIcon, RotateIcon, ShieldIcon, TruckIcon, WalletIcon } from "@/components/icons";
 import { findSlot, getCategories, getStaticImageSlots, safe } from "@/lib/api";
-import { buildCategoryTree, carouselCategories, findNode } from "@/lib/categoryTree";
-import { categoryHref } from "@/lib/slug";
+import { buildCategoryTree, findNode } from "@/lib/categoryTree";
+import { categoryHref, categorySlugFromLinkUrl } from "@/lib/slug";
 
 export const metadata: Metadata = {
   title: "فروش اقساطی",
@@ -32,19 +32,25 @@ export default async function InstallmentsPage() {
     safe(getCategories().then(buildCategoryTree), []),
     safe(getStaticImageSlots("home"), []),
   ]);
-  const level2 = carouselCategories(roots);
   const categoriesSlot = findSlot(slots, "categories");
-  const slotImages = categoriesSlot?.images ?? [];
+
+  // Match by the slug in each image's own linkUrl (…?category=mobile), not
+  // by array position — position assumes the business's upload order
+  // matches this page's HIGHLIGHT_IDS order, which isn't a real contract and
+  // was proven wrong in practice (a laptop photo landing on "موبایل"). See
+  // AGENTS.md "Static-image slots".
+  const artBySlug = new Map<string, string>();
+  for (const img of categoriesSlot?.images ?? []) {
+    const slug = categorySlugFromLinkUrl(img.linkUrl);
+    if (slug) artBySlug.set(slug, img.url);
+  }
 
   const highlights = HIGHLIGHT_IDS.map((id) => {
     // findNode searches the whole tree, not just level2 — "هندزفری و هدفون"
-    // (1232) is a level-3 category, not level-2, so level2.find missed it.
-    // The "categories" slot only has art for the level-2 list though, so a
-    // deeper id like this one always keeps its own placeholder.
+    // (1232) is a level-3 category, not level-2.
     const cat = findNode(roots, id);
     if (!cat) return null;
-    const index = level2.findIndex((c) => c.id === id);
-    const art = (index >= 0 && slotImages[index]?.url) || `/images/categories/${id}.svg`;
+    const art = artBySlug.get(cat.slug) || `/images/categories/${id}.svg`;
     return { id, label: cat.nameFa || cat.name, art, href: categoryHref(id, cat.nameFa, cat.name) };
   }).filter((x): x is NonNullable<typeof x> => Boolean(x));
 

src/app/page.tsx

@@ -14,7 +14,7 @@ import {
   getStoreSpecials,
   safe,
 } from "@/lib/api";
-import { buildCategoryTree, carouselCategories, findNode, subtreeIds } from "@/lib/categoryTree";
+import { buildCategoryTree, findNode, subtreeIds } from "@/lib/categoryTree";
 import { productToCard, specialToCards } from "@/lib/cards";
 import { blogHref, categoryHref } from "@/lib/slug";
 import { HOME_CAROUSELS } from "@/data/site";
@@ -57,8 +57,6 @@ export default async function HomePage() {
     safe(getStaticImageSlots("home"), []),
   ]);
 
-  const carouselCats = carouselCategories(categories);
-
   // Empty or failing slots fall through to each section's own placeholder —
   // findSlot() already returns undefined for an empty/missing key.
   const sliderSlot = findSlot(imageSlots, "slider");
@@ -141,7 +139,7 @@ export default async function HomePage() {
     <>
       <h1 className="sr-only">فروشگاه موبایل معلم | خرید موبایل، لپ‌تاپ و لوازم جانبی</h1>
       <HeroSlider slot={sliderSlot} slides={slides} />
-      <CategoryCarousel categories={carouselCats} slot={categoriesSlot} />
+      <CategoryCarousel roots={categories} slot={categoriesSlot} />
       <HotDeals products={deals} endsAt={endOfDay.getTime() + 2 * 86_400_000} />
       <ThreeBanners slot={threeBannerSlot} />
       {mobileCarousel && (

src/components/CategoryCarousel.tsx

@@ -6,24 +6,34 @@ import { FreeMode } from "swiper/modules";
 import { Swiper, SwiperSlide } from "swiper/react";
 import "swiper/css";
 import "swiper/css/free-mode";
-import { categoryHref } from "@/lib/slug";
+import { findNodeBySlug } from "@/lib/categoryTree";
+import { categoryHref, categorySlugFromLinkUrl } from "@/lib/slug";
 import type { CategoryNode, StaticImageSlot } from "@/lib/types";
 
-// Circular category thumbnails. The "categories" static-image slot has no
-// per-category id, so its images (kind: list, duplicatable) are matched
-// positionally to the category list, in the same order the business fills
-// them in — each still links to its real category page, only the art swaps.
-// A category past the end of the slot, or the whole thing when the slot is
-// empty, keeps its placeholder at public/images/categories/{id}.svg.
+// Fully slot-driven: each image in the "categories" slot carries its own
+// linkUrl (e.g. "...?category=mobile"), whose `category` param is the real
+// DB slug — that's what identifies which category a photo is for, not the
+// image's position in the list or its (business-typed, sometimes wrong)
+// titleFa. A category the business hasn't uploaded a photo for simply isn't
+// shown here — no placeholder, per the "only what's in the panel" brief.
+// See AGENTS.md "Static-image slots" for the mismatch this replaced.
 export default function CategoryCarousel({
-  categories,
+  roots,
   slot,
 }: {
-  categories: CategoryNode[];
+  roots: CategoryNode[];
   slot?: StaticImageSlot;
 }) {
-  if (categories.length === 0) return null;
-  const slotImages = slot?.images ?? [];
+  const items = (slot?.images ?? [])
+    .map((img) => {
+      const catSlug = categorySlugFromLinkUrl(img.linkUrl);
+      const cat = catSlug ? findNodeBySlug(roots, catSlug) : undefined;
+      if (!cat) return null;
+      return { key: img.id, art: img.url, cat };
+    })
+    .filter((x): x is { key: string; art: string; cat: CategoryNode } => Boolean(x));
+
+  if (items.length === 0) return null;
 
   return (
     <section className="boxed mt-8" aria-label="دسته‌بندی محصولات">
@@ -39,11 +49,10 @@ export default function CategoryCarousel({
           1024: { slidesPerView: 7 },
         }}
       >
-        {categories.map((cat, i) => {
+        {items.map(({ key, art, cat }) => {
           const label = cat.nameFa || cat.name;
-          const art = slotImages[i]?.url || `/images/categories/${cat.id}.svg`;
           return (
-            <SwiperSlide key={cat.id}>
+            <SwiperSlide key={key}>
               <Link href={categoryHref(cat.id, cat.nameFa, cat.name)} className="group flex flex-col items-center gap-2">
                 <span className="relative size-[104px] overflow-hidden rounded-full bg-surface transition group-hover:bg-brand-soft sm:size-[124px] lg:size-[140px]">
                   <Image src={art} alt={label} fill sizes="140px" className="object-contain p-3" />

src/lib/categoryTree.ts

@@ -35,6 +35,15 @@ export function findNode(nodes: CategoryNode[], id: string): CategoryNode | unde
   return undefined;
 }
 
+export function findNodeBySlug(nodes: CategoryNode[], slug: string): CategoryNode | undefined {
+  for (const node of nodes) {
+    if (node.slug === slug) return node;
+    const hit = findNodeBySlug(node.children, slug);
+    if (hit) return hit;
+  }
+  return undefined;
+}
+
 // Products are filed against leaf categories, so a parent like "لوازم جانبی"
 // matches almost nothing on its own — a carousel for it has to ask for the
 // whole subtree. Capped for the homepage's small carousels; a full category

src/lib/slug.ts

@@ -22,3 +22,18 @@ export function categoryHref(id: string, nameFa?: string | null, name?: string |
 export function blogHref(id: string, title?: string | null): string {
   return `/blog/${id}/${faSlug(title)}`;
 }
+
+// Static-image-slot items carry a business-picked linkUrl like
+// "https://moalem.shop/products?category=mobile" — the `category` query
+// param is the DB slug (ApiCategory.slug), the one reliable way to identify
+// which category an uploaded photo is actually for. Position in the list
+// and the item's own titleFa are NOT reliable — see AGENTS.md "Static-image
+// slots" for the real mismatch this was built to fix.
+export function categorySlugFromLinkUrl(linkUrl: string | null | undefined): string | null {
+  if (!linkUrl) return null;
+  try {
+    return new URL(linkUrl).searchParams.get("category");
+  } catch {
+    return null;
+  }
+}