Fall back to the plain detail layout when the carousel is confirmed empty

- carousel_supported now also checks a cheap cache peek (confirmed_empty):
  once a prior fetch found no trailer/photos for an item, later views skip
  the carousel grid entirely and render the same plain poster+text layout
  used by media types that never support a carousel (e.g. books), instead
  of reserving space for content that isn't coming.
- On a cold cache (first-ever view), the carousel grid still renders and
  lazy-loads as before; a CSS fallback collapses it to the same
  poster-beside-text arrangement if that first fetch turns up empty.
- Fixed a stray whitespace text node after the carousel fragment's
  {% endif %} that was defeating the CSS :empty check.

Author: dannyvfilms

src/app/carousel.py

@@ -8,6 +8,8 @@
 trailer or photo gallery.
 """
 
+from django.core.cache import cache
+
 from app.models import MediaTypes, Sources
 from app.providers import tmdb
 
@@ -21,6 +23,22 @@ def carousel_supported(media_type, source):
     return bool(source == Sources.IGDB.value and media_type == MediaTypes.GAME.value)
 
 
+def confirmed_empty(media_type, source, media_id, *, season_number=None) -> bool:
+    """Return True if a prior fetch already confirmed there's no trailer/photos.
+
+    Cache peek only (never fetches), so a page whose carousel was already
+    found empty on an earlier view can render the plain, non-carousel layout
+    up front instead of paying for the lazy carousel round trip again.
+    """
+    if source == Sources.TMDB.value and media_type in _TMDB_CAROUSEL_TYPES:
+        data = tmdb.peek_carousel_media(media_type, media_id, season_number=season_number)
+    elif source == Sources.IGDB.value and media_type == MediaTypes.GAME.value:
+        data = cache.get(f"igdb_carousel_v2_{media_id}")
+    else:
+        return False
+    return data is not None and not data["video"] and not data["photos"]
+
+
 def resolve_carousel_media(media_type, source, media_id, *, season_number=None) -> dict | None:
     """Return {"video": {...}|None, "photos": [{"url", "thumb_url"}, ...]} or None."""
     if source == Sources.TMDB.value and media_type in _TMDB_CAROUSEL_TYPES:

src/app/media_details_views.py

@@ -187,7 +187,10 @@ def media_details(
         )
 
     detail_view_started_at = time.perf_counter()
-    carousel_supported = carousel_media.carousel_supported(media_type, source)
+    carousel_supported = carousel_media.carousel_supported(
+        media_type,
+        source,
+    ) and not carousel_media.confirmed_empty(media_type, source, media_id)
     render_secondary_only = (
         request.GET.get("fragment") == DETAIL_SECONDARY_FRAGMENT
         and media_type != MediaTypes.PODCAST.value

src/app/providers/tmdb.py

@@ -1133,6 +1133,17 @@ def _parse_carousel_photos(response):
     ]
 
 
+def peek_carousel_media(media_type, media_id, season_number=None):
+    """Return the cached carousel payload, or None if nothing is cached yet.
+
+    Never triggers a provider fetch -- callers use this to check whether a
+    prior ``carousel_media`` call already confirmed there's no trailer/photos,
+    so the page can render the plain layout up front instead of paying for
+    the lazy carousel round trip again.
+    """
+    return cache.get(_carousel_cache_key(media_type, media_id, season_number))
+
+
 def carousel_media(media_type, media_id, season_number=None, language=None):
     """Return {"video": {...}|None, "photos": [...]} for the details carousel.
 

src/app/season_details_views.py

@@ -89,6 +89,11 @@ def season_details(
     detail_view_started_at = time.perf_counter()
     carousel_supported = carousel_media.carousel_supported(
         MediaTypes.SEASON.value, source
+    ) and not carousel_media.confirmed_empty(
+        MediaTypes.SEASON.value,
+        source,
+        media_id,
+        season_number=season_number,
     )
     render_secondary_only = request.GET.get("fragment") == DETAIL_SECONDARY_FRAGMENT
     defer_detail_secondary = not render_secondary_only

src/static/css/input.css

@@ -661,6 +661,22 @@ html.light .theme-toggle-icon-moon {
   .detail-carousel-grid__header {
     margin-top: 1.5rem;
   }
+
+  /* No trailer/photos to show (fragment swapped in empty): fall back to the
+     pre-carousel arrangement, poster beside the title/chips/synopsis column
+     instead of a carousel next to it, rather than stacking full-width rows
+     below the poster and leaving its column dead. */
+  .detail-carousel-grid:has(#detail-carousel-wrap:empty) {
+    grid-template-areas: "poster header" "poster chips" "poster synopsis";
+  }
+
+  .detail-carousel-grid:has(#detail-carousel-wrap:empty) .detail-carousel-grid__carousel {
+    display: none;
+  }
+
+  .detail-carousel-grid:has(#detail-carousel-wrap:empty) .detail-carousel-grid__header {
+    margin-top: 0;
+  }
 }
 
 /* Mobile default: active playback card spans all columns on very small screens */

src/static/css/main.css

@@ -2817,6 +2817,9 @@
   .pl-5 {
     padding-left: calc(var(--spacing) * 5);
   }
+  .pl-6 {
+    padding-left: calc(var(--spacing) * 6);
+  }
   .pl-7 {
     padding-left: calc(var(--spacing) * 7);
   }
@@ -6074,6 +6077,15 @@ html.light .theme-toggle-icon-moon {
   .detail-carousel-grid__header {
     margin-top: 1.5rem;
   }
+  .detail-carousel-grid:has(#detail-carousel-wrap:empty) {
+    grid-template-areas: "poster header" "poster chips" "poster synopsis";
+  }
+  .detail-carousel-grid:has(#detail-carousel-wrap:empty) .detail-carousel-grid__carousel {
+    display: none;
+  }
+  .detail-carousel-grid:has(#detail-carousel-wrap:empty) .detail-carousel-grid__header {
+    margin-top: 0;
+  }
 }
 [data-active-playback-card] {
   grid-column: span 3 !important;

src/templates/app/components/detail_carousel_fragment.html

@@ -157,4 +157,4 @@
     </template>
   </div>
 </div>
-{% endif %}
+{% endif %}