update shape of room instance browser

packages/domain/src/presence-db.ts

@@ -174,6 +174,35 @@ export async function countPlayersByRoom(
 	return new Map(results.map((r) => [r.roomId, r.n]))
 }
 
+/**
+ * Who is standing in each of a room's instances right now, keyed by instance id —
+ * one grouped query rather than a lookup per instance, so the owner's instance list
+ * stays a single read. Reads only unexpired presence; instances nobody is in are
+ * simply absent from the map (callers default to an empty list), and lobby
+ * (null-instance) presence is excluded.
+ */
+export async function getPlayerIdsByRoomInstance(
+	db: D1Database,
+	roomId: number,
+	now = nowSeconds()
+): Promise<Map<number, number[]>> {
+	const { results } = await db
+		.prepare(
+			`SELECT room_instance_id AS instanceId, account_id AS accountId FROM presence
+			 WHERE room_id = ?1 AND expires_at > ?2 AND room_instance_id IS NOT NULL
+			 ORDER BY account_id`
+		)
+		.bind(roomId, now)
+		.all<{ instanceId: number; accountId: number }>()
+	const out = new Map<number, number[]>()
+	for (const r of results) {
+		const players = out.get(r.instanceId)
+		if (players) players.push(r.accountId)
+		else out.set(r.instanceId, [r.accountId])
+	}
+	return out
+}
+
 /**
  * The room instances that expired presence rows still point at — the instances a
  * player was in when they stopped heartbeating (a crash or a hard quit, where no

packages/domain/src/room-instance-db.ts

@@ -12,7 +12,7 @@
  * the client DTO (`toDto`).
  */
 
-import { countPlayersInInstance } from './presence-db'
+import { countPlayersInInstance, getPlayerIdsByRoomInstance } from './presence-db'
 
 /** Schema DDL (mirror of migrations/0004_room_instance.sql). */
 export const ROOM_INSTANCE_SCHEMA_DDL: string[] = [
@@ -69,6 +69,22 @@ export interface RoomInstanceDto {
 	createdAt: string
 }
 
+/**
+ * The owner's view of one live instance of their room (`match`:
+ * `GET /room/:roomId/instances`). Deliberately NOT the client `RoomInstanceDto`:
+ * it's a management listing, so it carries who is in there (`playerIds`, from live
+ * presence) and drops the connection details (photon ids, data blob, room code) an
+ * owner has no business reading for a session they aren't in.
+ */
+export interface RoomInstanceSummary {
+	roomInstanceId: number
+	roomId: number
+	subRoomId: number
+	isFull: boolean
+	createdAt: string
+	playerIds: number[]
+}
+
 /** The full stored instance — the DTO plus the JsonIgnore fields (in the blob). */
 interface StoredRoomInstance extends RoomInstanceDto {
 	ownerAccountId: number
@@ -292,3 +308,34 @@ export async function getRoomInstancesByRoom(
 		.all<{ data: string }>()
 	return results.map((r) => toDto(parse(r.data)))
 }
+
+/**
+ * A room's instances as the owner's management listing sees them — the
+ * {@link RoomInstanceSummary} projection, each with the players currently standing
+ * in it. Presence is read once for the whole room (one grouped query), so this stays
+ * two reads regardless of how many instances are live; an instance nobody is in
+ * (everyone timed out, or it was just created) gets an empty `playerIds`.
+ */
+export async function getRoomInstanceSummariesByRoom(
+	db: D1Database,
+	roomId: number
+): Promise<RoomInstanceSummary[]> {
+	const [{ results }, playersByInstance] = await Promise.all([
+		db
+			.prepare('SELECT data FROM room_instance WHERE room_id = ?1 ORDER BY id')
+			.bind(roomId)
+			.all<{ data: string }>(),
+		getPlayerIdsByRoomInstance(db, roomId),
+	])
+	return results.map((r) => {
+		const s = parse(r.data)
+		return {
+			roomInstanceId: s.roomInstanceId,
+			roomId: s.roomId,
+			subRoomId: s.subRoomId,
+			isFull: s.isFull,
+			createdAt: s.createdAt,
+			playerIds: playersByInstance.get(s.roomInstanceId) ?? [],
+		}
+	})
+}