修复(#85): 按数量匹配订阅促销价

Co-authored-by: multica-agent <github@multica.ai>

internal/logic/public/order/preCreateOrderLogic.go

@@ -49,6 +49,7 @@ func (l *PreCreateOrderLogic) PreCreateOrder(req *types.PurchaseOrderRequest) (r
 	}
 
 	targetSubscribeID := req.SubscribeId
+	orderType := uint8(1)
 	isSingleModeRenewal := false
 	decision, routeErr := commonLogic.ResolvePurchaseRoute(
 		l.ctx,
@@ -68,6 +69,7 @@ func (l *PreCreateOrderLogic) PreCreateOrder(req *types.PurchaseOrderRequest) (r
 		targetSubscribeID = decision.ResolvedSubscribeID
 		isSingleModeRenewal = decision.Route == commonLogic.PurchaseRoutePurchaseToRenewal
 		if isSingleModeRenewal && decision.Anchor != nil {
+			orderType = 2
 			l.Infow("[PreCreateOrder] single mode purchase routed to renewal preview",
 				logger.Field("mode", "single"),
 				logger.Field("route", "purchase_to_renewal"),
@@ -77,6 +79,32 @@ func (l *PreCreateOrderLogic) PreCreateOrder(req *types.PurchaseOrderRequest) (r
 		}
 	}
 
+	// Keep promo eligibility preview aligned with Purchase: an existing paid subscription
+	// routes the request to renewal semantics, where first-purchase promos are disabled.
+	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 token != '' AND (order_id > 0 OR token LIKE 'iap:%')", u.Id).
+			Order("expire_time DESC").
+			Order("updated_at DESC").
+			Order("id DESC").
+			First(&existSub).Error; e == nil && existSub.Id > 0 && existSub.Token != "" {
+			orderType = 2
+			l.Infow("[PreCreateOrder] purchase preview routed to renewal because an existing subscription was found",
+				logger.Field("route_mode", "global_single_subscription"),
+				logger.Field("route", "purchase_to_existing_subscription"),
+				logger.Field("existing_subscribe_id", existSub.Id),
+				logger.Field("existing_status", existSub.Status),
+				logger.Field("user_id", u.Id),
+				logger.Field("resolved_subscribe_id", targetSubscribeID),
+			)
+		} else if e != nil && !errors.Is(e, gorm.ErrRecordNotFound) {
+			l.Errorw("[PreCreateOrder] Database query error", logger.Field("error", e.Error()), logger.Field("user_id", u.Id))
+			return nil, errors.Wrapf(xerr.NewErrCode(xerr.DatabaseQueryError), "find existing subscription error: %v", e.Error())
+		}
+	}
+
 	// find subscribe plan
 	sub, err := l.svcCtx.SubscribeModel.FindOne(l.ctx, targetSubscribeID)
 	if err != nil {
@@ -123,7 +151,7 @@ func (l *PreCreateOrderLogic) PreCreateOrder(req *types.PurchaseOrderRequest) (r
 		req.Quantity,
 		newUserDiscount.Discounts,
 		newUserDiscount.EligibleForDiscount,
-		!isSingleModeRenewal,
+		orderType == 1,
 	)
 	if err != nil {
 		l.Errorw("[PreCreateOrder] Promo price calculation error",

internal/logic/public/order/promoPricing.go

@@ -36,7 +36,7 @@ func calculatePurchasePrice(
 	}
 
 	if allowPromo {
-		promoResult, err := commonLogic.EvaluatePromo(ctx, svcCtx, userID, subscribeID)
+		promoResult, err := commonLogic.EvaluatePromo(ctx, svcCtx, userID, subscribeID, quantity)
 		if err != nil {
 			return nil, err
 		}

internal/logic/public/order/promoPricing_test.go

@@ -11,21 +11,30 @@ import (
 )
 
 type fakePromoModel struct {
-	rules []*promo.RuleWithPrice
+	rules            []*promo.RuleWithPrice
+	lastSubscribeID  int64
+	lastQuantity     int64
+	requireQuantity  int64
+	quantityMismatch []*promo.RuleWithPrice
 }
 
-func (m fakePromoModel) QueryEligibleRules(context.Context, int64) ([]*promo.RuleWithPrice, error) {
+func (m *fakePromoModel) QueryEligibleRules(_ context.Context, subscribeID int64, quantity int64) ([]*promo.RuleWithPrice, error) {
+	m.lastSubscribeID = subscribeID
+	m.lastQuantity = quantity
+	if m.requireQuantity > 0 && quantity != m.requireQuantity {
+		return m.quantityMismatch, nil
+	}
 	return m.rules, nil
 }
 
-func (m fakePromoModel) InsertUsage(context.Context, *promo.Usage, ...*gorm.DB) error {
+func (m *fakePromoModel) InsertUsage(context.Context, *promo.Usage, ...*gorm.DB) error {
 	return nil
 }
 
 func TestCalculatePurchasePricePromoSkipsPercentDiscount(t *testing.T) {
 	svcCtx := &svc.ServiceContext{
 		DB: &gorm.DB{},
-		PromoModel: fakePromoModel{rules: []*promo.RuleWithPrice{
+		PromoModel: &fakePromoModel{rules: []*promo.RuleWithPrice{
 			{
 				Rule: promo.Rule{
 					Id:      9,
@@ -73,7 +82,7 @@ func TestCalculatePurchasePricePromoSkipsPercentDiscount(t *testing.T) {
 func TestCalculatePurchasePriceIgnoresInvalidPromoPrice(t *testing.T) {
 	svcCtx := &svc.ServiceContext{
 		DB: &gorm.DB{},
-		PromoModel: fakePromoModel{rules: []*promo.RuleWithPrice{
+		PromoModel: &fakePromoModel{rules: []*promo.RuleWithPrice{
 			{
 				Rule: promo.Rule{
 					Id:      10,
@@ -111,3 +120,52 @@ func TestCalculatePurchasePriceIgnoresInvalidPromoPrice(t *testing.T) {
 		t.Fatalf("promo fields = (%d, %d), want (0, 0)", result.PromoRuleId, result.PromoDiscount)
 	}
 }
+
+func TestCalculatePurchasePricePassesQuantityToPromoEvaluation(t *testing.T) {
+	promoModel := &fakePromoModel{
+		requireQuantity: 6,
+		rules: []*promo.RuleWithPrice{
+			{
+				Rule: promo.Rule{
+					Id:      11,
+					Name:    "quantity campaign",
+					Type:    promo.RuleTypeCampaign,
+					Enabled: true,
+				},
+				PromoPrice: 500,
+			},
+		},
+	}
+	svcCtx := &svc.ServiceContext{
+		DB:         &gorm.DB{},
+		PromoModel: promoModel,
+	}
+
+	result, err := calculatePurchasePrice(
+		context.Background(),
+		svcCtx,
+		1,
+		2,
+		1000,
+		6,
+		[]types.SubscribeDiscount{{Quantity: 6, Discount: 80}},
+		true,
+		true,
+	)
+	if err != nil {
+		t.Fatalf("calculatePurchasePrice returned error: %v", err)
+	}
+
+	if promoModel.lastSubscribeID != 2 {
+		t.Fatalf("lastSubscribeID = %d, want 2", promoModel.lastSubscribeID)
+	}
+	if promoModel.lastQuantity != 6 {
+		t.Fatalf("lastQuantity = %d, want 6", promoModel.lastQuantity)
+	}
+	if result.PayableBase != 3000 {
+		t.Fatalf("PayableBase = %d, want 3000", result.PayableBase)
+	}
+	if result.PromoRuleId != 11 {
+		t.Fatalf("PromoRuleId = %d, want 11", result.PromoRuleId)
+	}
+}