towards multi-user

site/src/pages/activity/[id].astro

@@ -9,18 +9,38 @@ export async function getStaticPaths() {
   try {
     const candidates = [
       process.env.BINCIO_DATA_DIR,
-      resolve(process.cwd(), 'public', 'data'),  // symlinked by `bincio render`
+      resolve(process.cwd(), 'public', 'data'),
       resolve(process.cwd(), '..', 'bincio_data'),
     ].filter(Boolean) as string[];
-    const dataDir = candidates.find(d => { try { readFileSync(join(d, 'index.json')); return true; } catch { return false; } })!;
-    const raw = readFileSync(join(dataDir, 'index.json'), 'utf-8');
-    const index: BASIndex = JSON.parse(raw);
+    const dataDir = candidates.find(d => {
+      try { readFileSync(join(d, 'index.json')); return true; } catch { return false; }
+    })!;
 
-    return index.activities
+    const root: BASIndex = JSON.parse(readFileSync(join(dataDir, 'index.json'), 'utf-8'));
+
+    // Collect activities from root (single-user) or walk shards (multi-user)
+    function readActivities(indexPath: string): ActivitySummary[] {
+      try {
+        const idx: BASIndex = JSON.parse(readFileSync(indexPath, 'utf-8'));
+        const own = idx.activities ?? [];
+        const fromShards = (idx.shards ?? []).flatMap(s => {
+          const shardPath = join(dataDir, s.url);
+          return readActivities(shardPath);
+        });
+        return [...own, ...fromShards];
+      } catch {
+        return [];
+      }
+    }
+
+    const activities = readActivities(join(dataDir, 'index.json'));
+    const athlete = root.owner?.athlete ?? null;
+
+    return activities
       .filter(a => a.privacy !== 'private' && a.id)
       .map(a => ({
         params: { id: a.id },
-        props: { activity: a, athlete: index.owner.athlete ?? null },
+        props: { activity: a, athlete },
       }));
   } catch {
     return [];