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
}