Global feed: switch from sequential pages to month-based BAS shards

feed.json is now a BAS shard index pointing to feed-YYYY-MM.json files
(~150 activities / ~25 KB gzip each) instead of 400+ sequential feed-N.json
pages. The frontend can now jump directly to a specific month when filtering
by year or date range, without loading all newer data first.

- merge.py: write_combined_feed groups by YYYY-MM and emits a shard index
- dataloader.ts: isYearShardUrl matches feed-YYYY-MM.json; loadCombinedFeed
  returns pendingShards; FeedPage interface and loadCombinedFeedPage removed
- ActivityFeed.svelte: _yearFromShard handles both index-YYYY and feed-YYYY-MM;
  feedNextPage/feedTotalPages/loadingAllFeedPages removed; infinite-loop bug
  fixed (toLoad.length guard before setting loadingAllShards); onMount uses
  pendingShards from loadCombinedFeed

bincio/render/merge.py

@@ -412,10 +412,11 @@ _COMBINED_FEED_STRIP = _FEED_STRIP | {"mmp"}
 
 
 def write_combined_feed(data_dir: Path) -> int:
-    """Build data_dir/feed.json — the N most recent activities across all users.
+    """Build data_dir/feed.json and per-month data_dir/feed-YYYY-MM.json shards.
 
-    The global feed page loads this single file instead of resolving 20+ user
+    feed.json is a BAS shard index (same format as per-user index.json).
-    shards recursively.  Returns the number of activities written.
+    Each feed-YYYY-MM.json contains all activities for that month across all users,
+    sorted newest-first.  Returns the number of activities written.
     """
     user_dirs = sorted(
         p for p in data_dir.iterdir()
@@ -458,24 +459,35 @@ def write_combined_feed(data_dir: Path) -> int:
 
     all_activities.sort(key=lambda a: a.get("started_at", ""), reverse=True)
 
-    # Remove stale feed pages
+    # Remove stale feed files (sequential pages and old year shards)
     for f in data_dir.glob("feed*.json"):
         f.unlink(missing_ok=True)
 
     if not all_activities:
         return 0
 
-    pages = [all_activities[i:i + FEED_PAGE_SIZE] for i in range(0, len(all_activities), FEED_PAGE_SIZE)]
+    # Group by YYYY-MM (month), preserving newest-first order within each bucket
-    for page_num, page in enumerate(pages):
+    by_month: dict[str, list[dict]] = {}
-        slim = [{k: v for k, v in a.items() if k not in _COMBINED_FEED_STRIP} for a in page]
+    for a in all_activities:
-        fname = "feed.json" if page_num == 0 else f"feed-{page_num + 1}.json"
+        ym = (a.get("started_at") or "")[:7]  # "YYYY-MM"
-        doc = {
+        if len(ym) == 7 and ym[4] == "-":
+            by_month.setdefault(ym, []).append(a)
+
+    months_desc = sorted(by_month.keys(), reverse=True)
+
+    # Write per-month shard files (~150-200 acts each → ~25 KB gzip)
+    for ym, acts in by_month.items():
+        slim = [{k: v for k, v in a.items() if k not in _COMBINED_FEED_STRIP} for a in acts]
+        doc: dict = {"bas_version": "1.0", "activities": slim}
+        (data_dir / f"feed-{ym}.json").write_text(_dumps(doc))
+
+    # Write feed.json as a BAS shard index (same pattern as per-user index.json)
+    index_doc: dict = {
         "bas_version": "1.0",
-            "page": page_num + 1,
-            "total_pages": len(pages),
         "total_activities": len(all_activities),
-            "activities": slim,
+        "shards": [{"url": f"feed-{ym}.json"} for ym in months_desc],
+        "activities": [],
     }
-        (data_dir / fname).write_text(_dumps(doc))
+    (data_dir / "feed.json").write_text(_dumps(index_doc))
 
     return len(all_activities)

site/src/components/ActivityFeed.svelte

@@ -2,7 +2,7 @@
   import { onMount } from 'svelte';
   import type { ActivitySummary, BASIndex, Sport } from '../lib/types';
   import { formatDistance, formatDuration, formatElevation, formatDate, isUnlisted, sportIcon, sportColor, sportLabel } from '../lib/format';
-  import { loadIndexPaged, loadShardActivities, loadCombinedFeed, loadCombinedFeedPage } from '../lib/dataloader';
+  import { loadIndexPaged, loadShardActivities, loadCombinedFeed } from '../lib/dataloader';
 
   /** Render preview_coords as an SVG polyline path string. */
   function trackPath(coords: [number, number][] | null, w: number, h: number): string {
@@ -52,9 +52,6 @@
   let error = '';
   let mounted = false;
   let pendingShards: string[] = [];
-  /** Remaining combined-feed pages (multi-user global feed). */
-  let feedNextPage = 0;
-  let feedTotalPages = 0;
   /** Grand total from feed.json — shows instance-wide count even before all pages are loaded. */
   let totalActivities = 0;
   /** Logged-in handle — resolved async via bincio:me event. */
@@ -97,26 +94,19 @@
     : filtered;
   $: visible = withSearch.slice(0, shown);
   $: canShowMore = shown < withSearch.length;
-  $: hasMore = canShowMore || pendingShards.length > 0 || feedNextPage > 0;
+  $: hasMore = canShowMore || pendingShards.length > 0;
 
   async function loadMore() {
     if (canShowMore) {
       shown += PAGE_SIZE;
       return;
     }
+    if (!pendingShards.length) return;
     loadingMore = true;
     try {
-      let fresh: ActivitySummary[] = [];
-      if (feedNextPage > 0) {
-        fresh = await loadCombinedFeedPage(base, feedNextPage);
-        feedNextPage = feedNextPage < feedTotalPages ? feedNextPage + 1 : 0;
-      } else if (pendingShards.length) {
       const url = pendingShards[0];
       pendingShards = pendingShards.slice(1);
-        fresh = await loadShardActivities(url);
+      const fresh = await loadShardActivities(url);
-      } else {
-        return;
-      }
       const existing = new Map(all.map(a => [a.id, a]));
       for (const a of fresh) if (!existing.has(a.id)) existing.set(a.id, a);
       all = [...existing.values()].sort((a, b) =>
@@ -132,12 +122,11 @@
 
   $: if (sport || datePre || query || customFrom || customTo) shown = PAGE_SIZE; // reset pagination on filter change
 
-  // Eager-load shards / feed-pages when a filter needs data not yet in memory.
+  // Eager-load shards when a filter needs data not yet in memory.
   let loadingAllShards = false;
-  let loadingAllFeedPages = false;
 
   function _yearFromShard(url: string): number | null {
-    const m = url.match(/index-(\d{4})\.json$/);
+    const m = url.match(/(?:index|feed)-(\d{4})(?:-\d{2})?\.json$/);
     return m ? parseInt(m[1], 10) : null;
   }
 
@@ -157,13 +146,13 @@
     const yr = _neededYearRange(datePre, customFrom, customTo);
     const needEager = !!query.trim() || yr !== null;
     if (needEager && pendingShards.length > 0 && !loadingAllShards) {
-      loadingAllShards = true;
+      // Compute toLoad first — if empty (needed years already loaded, others remain),
-      // When year-specific filter (no search), load only shards that cover
+      // skip the async entirely to avoid an infinite reactive loop.
-      // the needed range; unneeded shards stay in pendingShards for "Load more".
-      // When search is active, load everything so full-text search works.
       const toLoad = (yr && !query.trim())
         ? pendingShards.filter(url => { const y = _yearFromShard(url); return y !== null && y >= yr[0] && y <= yr[1]; })
         : [...pendingShards];
+      if (toLoad.length > 0) {
+        loadingAllShards = true;
         (async () => {
           for (const url of toLoad) {
             pendingShards = pendingShards.filter(u => u !== url);
@@ -180,35 +169,6 @@
         })();
       }
     }
-
-  $: {
-    const yr = _neededYearRange(datePre, customFrom, customTo);
-    if ((!!query.trim() || yr !== null) && feedNextPage > 0 && !loadingAllFeedPages) {
-      loadingAllFeedPages = true;
-      // Capture at loop start — dateFrom is reactive and may change mid-fetch.
-      const effectiveFrom = dateFrom;
-      (async () => {
-        while (feedNextPage > 0) {
-          const page = feedNextPage;
-          feedNextPage = page < feedTotalPages ? page + 1 : 0;
-          try {
-            const fresh = await loadCombinedFeedPage(base, page);
-            const existing = new Map(all.map(a => [a.id, a]));
-            for (const a of fresh) if (!existing.has(a.id)) existing.set(a.id, a);
-            all = [...existing.values()].sort((a, b) =>
-              (b.started_at ?? '').localeCompare(a.started_at ?? ''),
-            );
-            // Feed is sorted newest-first. Once the oldest activity in this page
-            // predates our from-filter, everything needed is already loaded.
-            if (effectiveFrom && fresh.length > 0) {
-              const oldest = fresh.reduce((m, a) => (a.started_at ?? '') < (m.started_at ?? '') ? a : m);
-              if ((oldest.started_at ?? '') < effectiveFrom) { feedNextPage = 0; break; }
-            }
-          } catch { /* ignore — partial results still useful */ }
-        }
-        loadingAllFeedPages = false;
-      })();
-    }
   }
 
   $: if (mounted) {
@@ -245,8 +205,7 @@
         if (combined) {
           all = combined.activities;
           totalActivities = combined.totalActivities;
-          feedTotalPages = combined.remainingPages + 1;
+          pendingShards = combined.pendingShards;
-          feedNextPage = combined.remainingPages > 0 ? 2 : 0;
           loading = false;
           return;
         }
@@ -367,7 +326,7 @@
   <p class="text-red-400 text-center py-12">Could not load activities: {error}</p>
 {:else if withSearch.length === 0}
   <p class="text-zinc-500 text-center py-12">
-    {#if loadingAllFeedPages || loadingAllShards}Loading…{:else if query.trim()}No activities match "{query.trim()}".{:else}No activities found.{/if}
+    {#if loadingAllShards}Loading…{:else if query.trim()}No activities match "{query.trim()}".{:else}No activities found.{/if}
   </p>
 {:else}
   <div class="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 gap-4">
@@ -462,10 +421,8 @@
           Loading…
         {:else if canShowMore}
           Load more ({filtered.length - shown} remaining)
-        {:else if feedNextPage > 0}
-          Load more activities
         {:else}
-          Load older activities ({pendingShards.length} more {pendingShards.length === 1 ? 'year' : 'years'})
+          Load older activities ({pendingShards.length} more {pendingShards.length === 1 ? 'period' : 'periods'})
         {/if}
       </button>
     </div>

site/src/lib/dataloader.ts

@@ -58,7 +58,7 @@ function emptyIndex(): BASIndex {
 // ── Helpers ───────────────────────────────────────────────────────────────────
 
 function isYearShardUrl(url: string): boolean {
-  return /(?:^|\/)index-\d{4}\.json$/.test(url);
+  return /(?:^|\/)(?:index-\d{4}|feed-\d{4}-\d{2})\.json$/.test(url);
 }
 
 function rewriteActivityUrls(a: ActivitySummary, shardBase: string): ActivitySummary {
@@ -253,50 +253,28 @@ export async function loadShardActivities(shardUrl: string): Promise<ActivitySum
   }
 }
 
-interface FeedPage {
-  page: number;
-  total_pages: number;
-  total_activities: number;
-  activities: ActivitySummary[];
-}
-
 /**
- * Load the combined feed (multi-user global feed). Returns the first page of
+ * Load the combined feed (multi-user global feed).
- * activities pre-sorted across all users, plus remaining page count.
  *
- * Falls back to the full shard-resolution path if feed.json doesn't exist
+ * feed.json is now a BAS shard index: the most-recent year shard is fetched
- * (single-user installs, older data).
+ * immediately; older shards are returned as pendingShards for lazy loading.
+ * Returns null if feed.json doesn't exist (single-user installs).
  */
 export async function loadCombinedFeed(
   baseUrl: string,
-): Promise<{ activities: ActivitySummary[]; remainingPages: number; totalActivities: number } | null> {
+): Promise<{ activities: ActivitySummary[]; pendingShards: string[]; totalActivities: number } | null> {
   try {
-    const feed = await fetchJSON<FeedPage>(`${baseUrl}data/feed.json`);
+    const { index, pendingShards } = await loadIndexPaged(baseUrl, `${baseUrl}data/feed.json`);
     return {
-      activities: feed.activities ?? [],
+      activities: index.activities,
-      remainingPages: (feed.total_pages ?? 1) - 1,
+      pendingShards,
-      totalActivities: feed.total_activities ?? 0,
+      totalActivities: (index as any).total_activities ?? index.activities.length,
     };
   } catch {
     return null;
   }
 }
 
-/**
- * Load a subsequent page of the combined feed (feed-2.json, feed-3.json, etc.).
- */
-export async function loadCombinedFeedPage(
-  baseUrl: string,
-  page: number,
-): Promise<ActivitySummary[]> {
-  try {
-    const feed = await fetchJSON<FeedPage>(`${baseUrl}data/feed-${page}.json`);
-    return feed.activities ?? [];
-  } catch {
-    return [];
-  }
-}
-
 /**
  * Load a single activity detail, checking IndexedDB first so locally-converted
  * activities are available offline.