[match] add basic stat table for fun

packages/domain/src/index.ts

@@ -15,6 +15,7 @@ export * from './room-instance-db'
 export * from './room-comments-db'
 export * from './room-invites-db'
 export * from './presence-db'
+export * from './stats-db'
 export * from './gifts-db'
 export * from './inventory-invention-db'
 export * from './lists-db'

packages/domain/src/stats-db.ts

@@ -0,0 +1,45 @@
+/**
+ * Server statistics sampled over time (`stat` table). The `match` presence cron
+ * records one `online` sample per run — the count of live `presence` rows once the
+ * expired ones are swept. Migration: apps/match/migrations/0002_stat.sql.
+ */
+
+/** Schema DDL (mirror of apps/match/migrations/0002_stat.sql). */
+export const STAT_SCHEMA_DDL: string[] = [
+	`CREATE TABLE IF NOT EXISTS stat (
+		stat_type TEXT NOT NULL,
+		value INTEGER NOT NULL,
+		datetime TEXT NOT NULL
+	)`,
+	`CREATE INDEX IF NOT EXISTS idx_stat_type_datetime ON stat (stat_type, datetime)`,
+]
+
+export interface StatRow {
+	statType: string
+	value: number
+	datetime: string
+}
+
+/** Record one sample of `statType`, stamped with the current UTC time (ISO-8601). */
+export async function recordStat(
+	db: D1Database,
+	statType: string,
+	value: number,
+	now: Date = new Date()
+): Promise<void> {
+	await db
+		.prepare('INSERT INTO stat (stat_type, value, datetime) VALUES (?1, ?2, ?3)')
+		.bind(statType, value, now.toISOString())
+		.run()
+}
+
+/** Samples of `statType`, oldest first. */
+export async function getStats(db: D1Database, statType: string, limit = 1000): Promise<StatRow[]> {
+	const { results } = await db
+		.prepare(
+			'SELECT stat_type, value, datetime FROM stat WHERE stat_type = ?1 ORDER BY datetime ASC LIMIT ?2'
+		)
+		.bind(statType, limit)
+		.all<{ stat_type: string; value: number; datetime: string }>()
+	return results.map((r) => ({ statType: r.stat_type, value: r.value, datetime: r.datetime }))
+}