[econ] some invention stats

apps/econ/migrations/0026_invention_num_downloads.sql

@@ -0,0 +1,20 @@
+-- An invention's `NumDownloads` is the number of players who have it: the rows in
+-- `inventory_invention` that name it. `grantInvention` now re-derives it on every grant
+-- (packages/domain/src/inventory-invention-db.ts); every purchase before that left it at
+-- the 0 a save mints, so this backfills the inventions already bought.
+--
+-- The `invention` table is the `api` worker's (same database). `ModifiedAt` is left alone:
+-- being bought is not an edit of the invention.
+
+-- Backs that per-invention count; the primary key leads with account_id.
+-- Generated from INVENTORY_INVENTION_SCHEMA_DDL — keep in sync.
+CREATE INDEX IF NOT EXISTS idx_inventory_invention_invention
+  ON inventory_invention (invention_id);
+
+UPDATE invention
+SET data = json_set(
+  data,
+  '$.NumDownloads',
+  (SELECT COUNT(*) FROM inventory_invention WHERE invention_id = invention.id)
+)
+WHERE id IN (SELECT invention_id FROM inventory_invention);

apps/econ/src/econ.app.ts

@@ -2675,9 +2675,8 @@ interface SettledInventionPurchase {
  *
  * Ownership is recorded in `inventory_invention`; the creator is not sold their own
  * invention (they own it already, via CreatorPlayerId) and a re-buy is a 409 rather
- * than a second row. The invention’s `NumDownloads` counter is deliberately NOT
- * bumped: that column lives on the `invention` table the `api` worker owns, and this
- * worker only reads it.
+ * than a second row. The grant also resyncs the invention’s `NumDownloads` — the count
+ * of players who have it — and the invention returned carries the new number.
  */
 async function settleInventionPurchase(
 	c: Context<App>,
@@ -2723,7 +2722,7 @@ async function settleInventionPurchase(
 	// around them, so order them by what a failure costs. A buyer who paid and got the
 	// invention but left the creator unpaid is recoverable; a buyer charged for nothing
 	// is not.
-	await grantInvention(c.env.DB, id, inventionId)
+	const downloads = await grantInvention(c.env.DB, id, inventionId)
 
 	if (price > 0) {
 		// Seed the creator's signup grant BEFORE crediting them: `creditCurrency` upserts
@@ -2760,7 +2759,7 @@ async function settleInventionPurchase(
 	if (price > 0) {
 		await pushBalancePurchase(c, id, CurrencyType.RecCenterTokens, -price, balance)
 	}
-	return { invention, balance }
+	return { invention: { ...invention, NumDownloads: downloads }, balance }
 }
 
 // strict: false so trailing-slash routes (e.g. `/gifts/consume/`, which the client

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

@@ -5054,7 +5054,7 @@ describe('econ endpoints', () => {
 			}
 			InventionResponse: {
 				Status: number
-				Invention: { InventionId: number; Name: string }
+				Invention: { InventionId: number; Name: string; NumDownloads: number }
 				InventionVersion: { InventionId: number; VersionNumber: number }
 			}
 		}
@@ -5070,9 +5070,22 @@ describe('econ endpoints', () => {
 
 		expect(await getOwnedInventionIds(env.DB, 50)).toEqual([8])
 
-		// Owning an invention is boolean: buying it again is a conflict, not a second row.
+		// `NumDownloads` is the number of players who have it, re-derived on the grant:
+		// the response carries it and so does the stored record.
+		const storedDownloads = async (): Promise<number> =>
+			(
+				await env.DB.prepare(
+					"SELECT json_extract(data, '$.NumDownloads') AS n FROM invention WHERE id = 8"
+				).first<{ n: number }>()
+			)?.n ?? -1
+		expect(body.InventionResponse.Invention.NumDownloads).toBe(1)
+		expect(await storedDownloads()).toBe(1)
+
+		// Owning an invention is boolean: buying it again is a conflict, not a second row —
+		// and not a second download.
 		expect((await buyInvention('50', 8)).status).toBe(409)
 		expect(await getOwnedInventionIds(env.DB, 50)).toEqual([8])
+		expect(await storedDownloads()).toBe(1)
 	})
 
 	test('GET /api/storefronts/v2/buyInvention pays the creator the buyer’s tokens', async () => {