feat(server/pay): 优惠套餐(Promo SKU)每账号限购一次——已付过再下单 409 PROMO_ALREADY_USED

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01P9G7E3wmAYL9KeYCVZVsqu
2026-07-13 11:36:24 +08:00
parent 92943258ab
commit 1c2ec2844d
3 changed files with 106 additions and 0 deletions
@@ -158,6 +158,19 @@ func (s *Store) MarkCanceled(ctx context.Context, userID int64, outTradeNo strin
 	return nil
 }

+// HasPaidPurchase 该用户是否已有该 SKU 的 paid 台账——供优惠档(Promo SKU)限购一次校验用
+// (CreateOrder 在调上游前查,已购则 409 拒单,不打上游)。
+func (s *Store) HasPaidPurchase(ctx context.Context, userID int64, sku string) (bool, error) {
+	var n int
+	err := s.db.QueryRowContext(ctx,
+		`SELECT COUNT(*) FROM pay_purchases WHERE user_id = ? AND sku = ? AND status = 'paid'`,
+		userID, sku).Scan(&n)
+	if err != nil {
+		return false, fmt.Errorf("pay.Store.HasPaidPurchase: %w", err)
+	}
+	return n > 0, nil
+}
+
 // SubscriptionExpiry 查开通行的到期时间(查单响应回带给客户端)。
 func (s *Store) SubscriptionExpiry(ctx context.Context, subID int64) (time.Time, error) {
 	var exp time.Time