fix category images, gallery reset, scroll hint and orphan image cleanup

- category_nav pulls first product image per category from DB
- ProductImageScroll JS hook resets to index 0 on updated()
- collection filter bar gets CSS fade gradient scroll hint on mobile
- sync_product_images and delete_product_images now clean up orphaned
  Media.Image records to prevent DB bloat from repeated syncs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

assets/css/theme-semantic.css

@@ -206,6 +206,22 @@
   }
 }
 
+/* Horizontal scroll fade hint for collection category pills (mobile only) */
+.collection-filter-scroll {
+  mask-image: linear-gradient(to right, black calc(100% - 2rem), transparent);
+  -webkit-mask-image: linear-gradient(to right, black calc(100% - 2rem), transparent);
+  scrollbar-width: none;
+
+  &::-webkit-scrollbar {
+    display: none;
+  }
+
+  @media (min-width: 640px) {
+    mask-image: none;
+    -webkit-mask-image: none;
+  }
+}
+
 /* Skip link for keyboard navigation */
 .skip-link {
   position: absolute;

assets/js/app.js

@@ -290,17 +290,10 @@ const Lightbox = {
 
 const ProductImageScroll = {
   mounted() {
-    const container = this.el.parentElement
-    const dots = container.querySelector('.product-image-dots')
-    const spans = dots ? dots.querySelectorAll('.product-image-dot') : []
-    const lightbox = container.parentElement.querySelector('dialog')
-    const thumbs = container.parentElement.querySelector('.pdp-gallery-thumbs')
-    const thumbButtons = thumbs ? thumbs.querySelectorAll('.pdp-thumbnail') : []
-    const imageCount = this.el.children.length
-
     this.el.addEventListener('scroll', () => {
+      const {dots, thumbButtons, lightbox} = this._queryDom()
       const index = Math.round(this.el.scrollLeft / this.el.offsetWidth)
-      spans.forEach((dot, i) => {
+      dots.forEach((dot, i) => {
         dot.classList.toggle('product-image-dot-active', i === index)
       })
       thumbButtons.forEach((btn, i) => {
@@ -316,15 +309,32 @@ const ProductImageScroll = {
 
     this.el.addEventListener('pdp:scroll-prev', () => {
       const current = Math.round(this.el.scrollLeft / this.el.offsetWidth)
-      const target = (current - 1 + imageCount) % imageCount
+      const count = this.el.children.length
+      const target = (current - 1 + count) % count
       this.el.scrollTo({left: target * this.el.offsetWidth, behavior: 'smooth'})
     })
 
     this.el.addEventListener('pdp:scroll-next', () => {
       const current = Math.round(this.el.scrollLeft / this.el.offsetWidth)
-      const target = (current + 1) % imageCount
+      const count = this.el.children.length
+      const target = (current + 1) % count
       this.el.scrollTo({left: target * this.el.offsetWidth, behavior: 'smooth'})
     })
+  },
+
+  updated() {
+    this.el.scrollTo({left: 0, behavior: 'instant'})
+  },
+
+  _queryDom() {
+    const container = this.el.parentElement
+    const dotsEl = container.querySelector('.product-image-dots')
+    return {
+      dots: dotsEl ? dotsEl.querySelectorAll('.product-image-dot') : [],
+      thumbButtons: container.parentElement.querySelector('.pdp-gallery-thumbs')
+        ?.querySelectorAll('.pdp-thumbnail') || [],
+      lightbox: container.parentElement.querySelector('dialog')
+    }
   }
 }
 

lib/simpleshop_theme/products.ex

@@ -153,7 +153,8 @@ defmodule SimpleshopTheme.Products do
 
   @doc """
   Lists distinct categories from visible, active products.
-  Returns a list of %{name: "Category", slug: "category"}.
+  Returns a list of `%{name, slug, image_url}` where `image_url` is the
+  first product image for a representative product in that category.
   """
   def list_categories do
     from(p in Product,
@@ -163,7 +164,29 @@ defmodule SimpleshopTheme.Products do
       order_by: p.category
     )
     |> Repo.all()
-    |> Enum.map(fn name -> %{name: name, slug: Slug.slugify(name)} end)
+    |> Enum.map(fn name ->
+      image_url = category_image_url(name)
+      %{name: name, slug: Slug.slugify(name), image_url: image_url}
+    end)
+  end
+
+  defp category_image_url(category_name) do
+    from(pi in ProductImage,
+      join: p in Product,
+      on: pi.product_id == p.id,
+      where:
+        p.visible == true and p.status == "active" and
+          p.category == ^category_name,
+      order_by: [asc: pi.position],
+      limit: 1,
+      select: {pi.image_id, pi.src}
+    )
+    |> Repo.one()
+    |> case do
+      {id, _src} when not is_nil(id) -> "/images/#{id}/variant/400.webp"
+      {_, src} when is_binary(src) -> src
+      _ -> nil
+    end
   end
 
   @doc """
@@ -480,11 +503,23 @@ defmodule SimpleshopTheme.Products do
   end
 
   @doc """
-  Deletes all images for a product.
+  Deletes all images for a product, including their backing Media.Image records.
   """
   def delete_product_images(%Product{id: product_id}) do
-    from(i in ProductImage, where: i.product_id == ^product_id)
+    image_ids =
+      from(pi in ProductImage,
+        where: pi.product_id == ^product_id and not is_nil(pi.image_id),
+        select: pi.image_id
+      )
+      |> Repo.all()
+
+    result =
+      from(pi in ProductImage, where: pi.product_id == ^product_id)
       |> Repo.delete_all()
+
+    cleanup_orphaned_images(image_ids)
+
+    result
   end
 
   @doc """
@@ -507,19 +542,26 @@ defmodule SimpleshopTheme.Products do
       |> MapSet.new()
 
     # Delete orphaned positions (images no longer in the list)
-    orphaned_ids =
+    orphaned =
       existing_by_position
       |> Enum.reject(fn {position, _img} -> MapSet.member?(incoming_positions, position) end)
-      |> Enum.map(fn {_position, img} -> img.id end)
+
+    orphaned_ids = Enum.map(orphaned, fn {_position, img} -> img.id end)
+
+    orphaned_image_ids =
+      orphaned
+      |> Enum.map(fn {_position, img} -> img.image_id end)
+      |> Enum.reject(&is_nil/1)
 
     if orphaned_ids != [] do
       from(i in ProductImage, where: i.id in ^orphaned_ids) |> Repo.delete_all()
     end
 
-    # Upsert incoming images
+    # Upsert incoming images, collecting image_ids displaced by URL changes
+    {results, replaced_image_ids} =
       images
       |> Enum.with_index()
-    |> Enum.map(fn {image_data, index} ->
+      |> Enum.map_reduce([], fn {image_data, index}, acc ->
         position = image_data[:position] || index
         src = image_data[:src]
         existing = Map.get(existing_by_position, position)
@@ -527,6 +569,7 @@ defmodule SimpleshopTheme.Products do
         cond do
           # Same URL at position - update color if needed, preserve image_id
           existing && existing.src == src ->
+            result =
               if existing.color != image_data[:color] do
                 existing
                 |> ProductImage.changeset(%{color: image_data[:color]})
@@ -535,8 +578,13 @@ defmodule SimpleshopTheme.Products do
                 {:ok, existing}
               end
 
+            {result, acc}
+
           # Different URL at position - update src, clear image_id (triggers re-download)
           existing ->
+            acc = if existing.image_id, do: [existing.image_id | acc], else: acc
+
+            result =
               existing
               |> ProductImage.changeset(%{
                 src: src,
@@ -546,6 +594,8 @@ defmodule SimpleshopTheme.Products do
               })
               |> Repo.update()
 
+            {result, acc}
+
           # New position - create new
           true ->
             attrs =
@@ -553,9 +603,23 @@ defmodule SimpleshopTheme.Products do
               |> Map.put(:product_id, product_id)
               |> Map.put(:position, position)
 
-          create_product_image(attrs)
+            {create_product_image(attrs), acc}
         end
       end)
+
+    cleanup_orphaned_images(orphaned_image_ids ++ replaced_image_ids)
+
+    results
+  end
+
+  # Deletes Media.Image records that are no longer referenced by any product_image.
+  defp cleanup_orphaned_images([]), do: :ok
+
+  defp cleanup_orphaned_images(image_ids) do
+    alias SimpleshopTheme.Media.Image, as: ImageSchema
+
+    from(i in ImageSchema, where: i.id in ^image_ids)
+    |> Repo.delete_all()
   end
 
   # =============================================================================

lib/simpleshop_theme/theme/preview_data.ex

@@ -366,20 +366,7 @@ defmodule SimpleshopTheme.Theme.PreviewData do
   end
 
   defp get_real_categories do
-    Products.list_products(visible: true, status: "active")
+    Products.list_categories()
-    |> Enum.map(& &1.category)
-    |> Enum.reject(&is_nil/1)
-    |> Enum.frequencies()
-    |> Enum.map(fn {name, count} ->
-      %{
-        id: Slug.slugify(name),
-        name: name,
-        slug: Slug.slugify(name),
-        product_count: count,
-        image_url: nil
-      }
-    end)
-    |> Enum.sort_by(& &1.name)
   end
 
   defp mock_products do

lib/simpleshop_theme_web/live/shop/collection.ex

@@ -135,7 +135,10 @@ defmodule SimpleshopThemeWeb.Shop.Collection do
   defp collection_filter_bar(assigns) do
     ~H"""
     <div class="flex flex-wrap items-center justify-between gap-3 mb-6">
-      <nav aria-label="Collection filters" class="overflow-x-auto -mx-4 px-4 sm:mx-0 sm:px-0">
+      <nav
+        aria-label="Collection filters"
+        class="collection-filter-scroll overflow-x-auto py-1 -mx-4 px-4 sm:overflow-visible sm:mx-0 sm:px-0 sm:py-0"
+      >
         <ul class="flex gap-1.5 sm:flex-wrap sm:gap-2">
           <li class="shrink-0">
             <.link