gpt

internal/mysqldao/member_quota.go

@@ -0,0 +1,58 @@
+package mysqldao
+
+import (
+	"context"
+	"fmt"
+
+	"git.lzcwy.cn/zhengchiliu/zt-closet-backend/global"
+	"git.lzcwy.cn/zhengchiliu/zt-closet-backend/internal/mysqlmodel"
+	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
+)
+
+// MemberQuotaGrantCreateWithFlow 按用户、会员商品、额度类型仅发放一次。
+// 锁定用户行将同一用户的并发续费串行化，检查与写入使用同一事务。
+// 保留原始订单号用于退款追溯；历史凭证（包括已退款软删除的凭证）也参与去重，
+// 因而额度用完、会员过期或退款后再次购买都不会重新领取首次赠送。
+func (d *QuotaGrantDao) MemberQuotaGrantCreateWithFlow(ctx context.Context, goodsID int64, grant *mysqlmodel.QuotaGrant, flow *mysqlmodel.QuotaFlowLog) (bool, error) {
+	ctx, span := global.Tracer.Start(ctx, "mysqldao.MemberQuotaGrantCreateWithFlow")
+	defer span.End()
+	if goodsID <= 0 || grant == nil || flow == nil || grant.UserID <= 0 || grant.RefID == "" || grant.Source != 1 {
+		return false, fmt.Errorf("invalid member quota grant")
+	}
+	created := false
+	err := d.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
+		var user mysqlmodel.User
+		if err := tx.Select("id").Clauses(clause.Locking{Strength: "UPDATE"}).
+			Where("id = ?", grant.UserID).First(&user).Error; err != nil {
+			return err
+		}
+		// 当前读确保 MySQL REPEATABLE READ 下等待用户锁后可见上一事务的发放。
+		// 关联订单快照识别商品，不依赖当前商品名称或用户是否仍为新用户。
+		var previous []mysqlmodel.QuotaGrant
+		if err := tx.Unscoped().Model(&mysqlmodel.QuotaGrant{}).
+			Select("quota_grants.*").
+			Joins("JOIN orders ON orders.order_no = quota_grants.ref_id AND orders.user_id = quota_grants.user_id").
+			Where("quota_grants.user_id = ? AND orders.goods_id = ? AND quota_grants.quota_type = ? AND quota_grants.source = ?", grant.UserID, goodsID, grant.QuotaType, grant.Source).
+			Clauses(clause.Locking{Strength: "UPDATE"}).Limit(1).Find(&previous).Error; err != nil {
+			return err
+		}
+		if len(previous) > 0 {
+			return nil
+		}
+		if err := tx.Create(grant).Error; err != nil {
+			return err
+		}
+		ensureFlowOrderNo(flow)
+		if err := tx.Create(flow).Error; err != nil {
+			return err
+		}
+		created = true
+		return nil
+	})
+	if err != nil {
+		span.RecordError(err)
+		return false, err
+	}
+	return created, nil
+}