fix(og): match plain URL slugs; fix Funkwhale GC wipe

og-fix transform was matching date-based URL segments
(/type/yyyy/MM/dd/slug/) that this site never uses — posts live at
/type/slug/. Every post therefore fell through to the default OG image.

Fixed by updating the regex to /type/slug/index.html and deriving the OG
slug as the bare last URL segment, which matches the filename og.js
already generates. The ogSlug filter is simplified accordingly.

Funkwhale GC bug: gcFunkwhaleImages() deleted the entire image cache
whenever _activeFilenames was empty — which happens if the API returns
valid stats but no listenings with cover URLs. Guard added: GC is
skipped when no images were referenced this build.

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

eleventy.config.js

@@ -403,19 +403,18 @@ export default function (eleventyConfig) {
     if (!outputPath || !outputPath.endsWith(".html")) return content;
 
     // Derive correct page URL and OG slug from outputPath (immune to race condition)
-    // Content pages match: .../type/yyyy/MM/dd/slug/index.html
-    const dateMatch = outputPath.match(
-      /\/([\w-]+)\/(\d{4})\/(\d{2})\/(\d{2})\/([\w-]+)\/index\.html$/
+    // Content pages match: .../type/slug/index.html (plain URLs, no date segments)
+    const postMatch = outputPath.match(
+      /\/([\w-]+)\/([\w-]+)\/index\.html$/
     );
 
-    if (dateMatch) {
-      const [, type, year, month, day, slug] = dateMatch;
-      const pageUrlPath = `/${type}/${year}/${month}/${day}/${slug}/`;
+    if (postMatch) {
+      const [, type, slug] = postMatch;
+      const pageUrlPath = `/${type}/${slug}/`;
       const correctFullUrl = `${siteUrl}${pageUrlPath}`;
-      const ogSlug = `${year}-${month}-${day}-${slug}`;
-      const hasOg = hasOgImage(ogSlug);
+      const hasOg = hasOgImage(slug);
       const ogImageUrl = hasOg
-        ? `${siteUrl}/og/${ogSlug}.png`
+        ? `${siteUrl}/og/${slug}.png`
         : `${siteUrl}/images/og-default.png`;
       const twitterCard = hasOg ? "summary_large_image" : "summary";
 
@@ -433,7 +432,7 @@ export default function (eleventyConfig) {
       content = content.replace(/__OG_IMAGE_PLACEHOLDER__/g, ogImageUrl);
       content = content.replace(/__TWITTER_CARD_PLACEHOLDER__/g, twitterCard);
     } else {
-      // Non-date pages (homepage, about, etc.): use defaults
+      // Non-post pages (homepage, archives, etc.): use defaults
       content = content.replace(
         /__OG_IMAGE_PLACEHOLDER__/g,
         `${siteUrl}/images/og-default.png`
@@ -916,16 +915,10 @@ export default function (eleventyConfig) {
 
   // Derive OG slug from page.url (reliable) instead of page.fileSlug
   // (which suffers from Nunjucks race conditions in Eleventy 3.x parallel rendering).
-  // OG images are named with the full date prefix to match URL segments exactly.
+  // URLs are plain (/type/slug/), so the slug is the last path segment.
   eleventyConfig.addFilter("ogSlug", (url) => {
     if (!url) return "";
     const segments = url.split("/").filter(Boolean);
-    // Date-based URL: /type/yyyy/MM/dd/slug/ → 5 segments → "yyyy-MM-dd-slug"
-    if (segments.length === 5) {
-      const [, year, month, day, slug] = segments;
-      return `${year}-${month}-${day}-${slug}`;
-    }
-    // Fallback: last segment (for pages, legacy URLs)
     return segments[segments.length - 1] || "";
   });
 

lib/cache-funkwhale-image.js

@@ -76,6 +76,10 @@ export async function cacheFunkwhaleImage(url) {
  */
 export function gcFunkwhaleImages() {
   if (!existsSync(CACHE_DIR)) return;
+  // If no images were referenced this build, skip GC — likely the API returned no
+  // cover URLs (empty listenings, null covers, or stats-only response). Deleting
+  // everything from an empty _activeFilenames set would wipe a valid cache.
+  if (_activeFilenames.size === 0) return;
   let deleted = 0;
   for (const file of readdirSync(CACHE_DIR)) {
     if (!_activeFilenames.has(file)) {

lib/og.js

@@ -126,7 +126,8 @@ function formatDate(dateStr) {
 }
 
 /**
- * Use the full filename (with date prefix) as the OG image slug.
+ * Use the filename (without extension) as the OG image slug.
+ * Matches the last URL path segment, which Eleventy derives from the filename.
  */
 function toOgSlug(filename) {
   return filename;