adjust "top" window

apps/api/src/inventions-db.ts

@@ -352,23 +352,29 @@ async function publicInventions(db: D1Database, featuredOnly = false): Promise<S
 	return results.map((r) => JSON.parse(r.data) as SavedInvention)
 }
 
-/** Midnight UTC today, as the ISO timestamp `acquired_at` is compared against. */
-function startOfUtcDay(): string {
-	return `${new Date().toISOString().slice(0, 10)}T00:00:00.000Z`
+/** Length of the "today" window — a trailing day, not the calendar one. */
+const TOP_TODAY_WINDOW_MS = 24 * 60 * 60 * 1000
+
+/** 24 hours ago, as the ISO timestamp `acquired_at` is compared against. */
+function startOfWindow(): string {
+	return new Date(Date.now() - TOP_TODAY_WINDOW_MS).toISOString()
 }
 
 /**
- * The "top today" feed — the inventions other players picked up TODAY, most first.
+ * The "top today" feed — the inventions other players picked up in the last 24 hours,
+ * most first.
  *
  * Ranked from the acquisitions the `econ` worker records in `inventory_invention` at
  * purchase time, grouped by invention, rather than from the lifetime counters on the
  * invention itself: those never reset, so "top today" used to mean "top ever" and the
  * shelf only changed when something overtook a total built up over months.
  *
- * "Today" is the UTC day, matching the timestamps econ writes. The day therefore rolls
- * over at 00:00 UTC wherever the player is, and the feed IS EMPTY until the first
- * acquisition of that day — nothing stands in for it, the same way the featured feed
- * serves nothing while nothing is curated.
+ * "Today" is a TRAILING 24 hours, not the calendar UTC day, so the feed doesn't empty
+ * itself at midnight UTC and slowly refill through the small hours — it always covers a
+ * full day's worth of activity. It is still genuinely a window: an invention nobody has
+ * picked up since yesterday falls off, and the feed IS EMPTY when nothing at all was
+ * acquired in a day. Nothing stands in for it, the same way the featured feed serves
+ * nothing while nothing is curated.
  *
  * An acquired invention that has since been unpublished or hidden drops out: this is a
  * public feed, so it is filtered like every other one. Paginated via skip/take AFTER
@@ -379,7 +385,7 @@ export async function getTopInventions(
 	skip: number,
 	take: number
 ): Promise<SavedInvention[]> {
-	const counts = await getInventionAcquisitionCounts(db, startOfUtcDay())
+	const counts = await getInventionAcquisitionCounts(db, startOfWindow())
 	if (counts.length === 0) return []
 
 	// getInventionsByIds answers in the order it is asked, so the ranking survives the

apps/api/src/routes/avatar.ts

@@ -622,7 +622,7 @@ export const avatarRoutes = new Hono<App>({ strict: false })
 		}
 	)
 
-	// The "top today" invention feed — the inventions most acquired since 00:00 UTC,
+	// The "top today" invention feed — the inventions most acquired in the last 24 hours,
 	// counted from the purchase rows the `econ` worker writes. A real day window, so an
 	// empty list is a quiet day rather than a bug. Paginated via skip/take (take defaults
 	// to 50, as the client asks for). Bare array.
@@ -632,10 +632,11 @@ export const avatarRoutes = new Hono<App>({ strict: false })
 			tags: ['Inventions'],
 			summary: 'The “top today” feed',
 			description:
-				'Published inventions ranked by how many players acquired them TODAY (since ' +
-				'00:00 UTC), counted from the purchase records — free grants included, one per ' +
-				'player per invention. Genuinely a day window: empty until the day’s first ' +
-				'acquisition, and it resets at midnight UTC.',
+				'Published inventions ranked by how many players acquired them in the last 24 ' +
+				'hours, counted from the purchase records — free grants included, one per ' +
+				'player per invention. Genuinely a window: an invention nobody has picked up ' +
+				'since yesterday falls off, and a day with no acquisitions at all serves an ' +
+				'empty list. It trails the clock rather than resetting at midnight.',
 			parameters: pageParams(50),
 			responses: { 200: json(InventionDto.array(), 'The top inventions') },
 		}),

apps/api/src/test/integration/api.test.ts

@@ -1184,22 +1184,23 @@ describe('public endpoints', () => {
 				.run()
 		}
 
-		// Today's acquisitions, which is what "top today" now counts: 201 picked up by three
+		// Recent acquisitions, which is what "top today" now counts: 201 picked up by three
 		// players, 203 by one. 204/205 are acquired too — an unpublished and a hidden
 		// invention can still be owned — and must not surface in a public feed.
 		for (const accountId of [7001, 7002, 7003]) await grantInvention(env.DB, accountId, 201)
 		await grantInvention(env.DB, 7001, 203)
 		await grantInvention(env.DB, 7001, 204)
 		await grantInvention(env.DB, 7002, 205)
-		// 202 was acquired, but not today — the window is the current UTC day, so it is out.
+		// 202 was acquired 25 hours ago, just past the trailing 24-hour window, so it is out —
+		// the feed really does forget, rather than accumulating every acquisition ever.
 		await env.DB.prepare(
 			'INSERT INTO inventory_invention (account_id, invention_id, acquired_at) VALUES (?1, ?2, ?3)'
 		)
-			.bind(7004, 202, '2020-01-01T00:00:00.000Z')
+			.bind(7004, 202, new Date(Date.now() - 25 * 60 * 60 * 1000).toISOString())
 			.run()
 
-		// Top: most acquisitions today first. Download counts no longer rank anything — 202
-		// has the biggest of them and is absent entirely.
+		// Top: most acquisitions in the window first. Download counts no longer rank anything —
+		// 202 has the biggest of them and is absent entirely.
 		const top = await ids(await exports.default.fetch(`${ORIGIN}/api/inventions/v1/toptoday`))
 		expect(top).toEqual([201, 203])
 

packages/domain/src/inventory-invention-db.ts

@@ -65,7 +65,7 @@ export async function ownsInvention(
 /**
  * How many times each invention was acquired at or after `since`, most-acquired first
  * (ties broken by newest invention, so paging is stable). Backs the `api` worker's "top
- * today" feed, which passes the start of the current UTC day.
+ * today" feed, which passes 24 hours ago.
  *
  * `acquired_at` holds `toISOString()` output, which is fixed-width UTC, so a lexical
  * `>=` on the string is a chronological comparison — no date parsing in SQL.