fix(order): prevent duplicate subscriptions and repair invite gifts

internal/logic/public/order/purchaseLogic.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"math"
+	"strings"
 	"time"
 
 	"github.com/google/uuid"
@@ -111,18 +112,21 @@ func (l *PurchaseLogic) Purchase(req *types.PurchaseOrderRequest) (resp *types.P
 		}
 	}
 
-	// 非单订阅模式下，若用户已有同套餐订阅（含过期），提前路由为续费，防止创建重复订阅
+	// 全局单订阅口径：若用户已有任意付费订阅（含过期），提前路由为续费/换套餐，
+	// 防止不同套餐购买创建第二条订阅。
 	if !l.svcCtx.Config.Subscribe.SingleModel && orderType == 1 {
 		var existSub user.Subscribe
 		if e := l.svcCtx.DB.WithContext(l.ctx).
 			Model(&user.Subscribe{}).
-			Where("user_id = ? AND subscribe_id = ?", entitlement.EffectiveUserID, targetSubscribeID).
+			Where("user_id = ? AND token != '' AND (order_id > 0 OR token LIKE 'iap:%')", entitlement.EffectiveUserID).
 			Order("expire_time DESC").
+			Order("updated_at DESC").
+			Order("id DESC").
 			First(&existSub).Error; e == nil && existSub.Id > 0 && existSub.Token != "" {
 			orderType = 2
 			parentOrderID = existSub.OrderId
 			subscribeToken = existSub.Token
-			l.Infow("[Purchase] non-single mode purchase routed to renewal (existing subscription found)",
+			l.Infow("[Purchase] purchase routed to renewal/change plan (existing subscription found)",
 				logger.Field("existing_subscribe_id", existSub.Id),
 				logger.Field("existing_status", existSub.Status),
 				logger.Field("user_id", u.Id),
@@ -311,13 +315,13 @@ func (l *PurchaseLogic) Purchase(req *types.PurchaseOrderRequest) (resp *types.P
 		// check subscribe plan quota limit inside transaction to prevent race condition
 		if orderInfo.Type == 1 && sub.Quota > 0 {
 			var currentUserSub []user.Subscribe
-			if e := db.Model(&user.Subscribe{}).Where("user_id = ?", u.Id).Find(&currentUserSub).Error; e != nil {
+			if e := db.Model(&user.Subscribe{}).Where("user_id = ?", entitlement.EffectiveUserID).Find(&currentUserSub).Error; e != nil {
 				l.Errorw("[Purchase] Database query error", logger.Field("error", e.Error()), logger.Field("user_id", u.Id))
 				return e
 			}
 			var count int64
 			for _, v := range currentUserSub {
-				if v.SubscribeId == targetSubscribeID {
+				if v.OrderId > 0 || strings.HasPrefix(v.Token, "iap:") {
 					count++
 				}
 			}