新功能(#76): 促销系统下单流程集成

- 新增促销规则/规格促销价/使用记录模型与幂等迁移
- EvaluatePromo 支持 new_user/inactive_user/campaign 规则判定
- purchase/preCreate 接入促销判定：命中促销时跳过百分比折扣
- activate 激活后按 order_no 幂等写入 promo_usage
- 订单模型和响应结构新增 promo_rule_id、promo_discount 字段

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

internal/logic/common/promoEligibility.go

@@ -0,0 +1,170 @@
+package common
+
+import (
+	"context"
+	"encoding/json"
+	"time"
+
+	"github.com/perfect-panel/server/internal/model/promo"
+	"github.com/perfect-panel/server/internal/model/user"
+	"github.com/perfect-panel/server/internal/svc"
+	"github.com/perfect-panel/server/pkg/xerr"
+	"github.com/pkg/errors"
+	"gorm.io/gorm"
+)
+
+type PromoResult struct {
+	Eligible   bool
+	RuleID     int64
+	RuleName   string
+	RuleType   string
+	PromoPrice int64
+	ExpiresAt  time.Time
+}
+
+type promoRuleParams struct {
+	WindowHours    int `json:"window_hours"`
+	InactiveMonths int `json:"inactive_months"`
+}
+
+func EvaluatePromo(ctx context.Context, svcCtx *svc.ServiceContext, userID int64, subscribeID int64) (*PromoResult, error) {
+	result := &PromoResult{}
+	if svcCtx == nil || svcCtx.PromoModel == nil || svcCtx.DB == nil || userID <= 0 || subscribeID <= 0 {
+		return result, nil
+	}
+
+	rules, err := svcCtx.PromoModel.QueryEligibleRules(ctx, subscribeID)
+	if err != nil {
+		return nil, errors.Wrapf(xerr.NewErrCode(xerr.DatabaseQueryError), "query promo rules failed: %v", err.Error())
+	}
+	if len(rules) == 0 {
+		return result, nil
+	}
+
+	var currentUser user.User
+	now := time.Now()
+	for _, rule := range rules {
+		if rule == nil || !isPromoRuleInTimeWindow(rule, now) {
+			continue
+		}
+		if rule.PromoPrice <= 0 {
+			continue
+		}
+
+		params := promoRuleParams{}
+		if rule.Params != "" {
+			if err = json.Unmarshal([]byte(rule.Params), &params); err != nil {
+				continue
+			}
+		}
+
+		eligible, expiresAt, err := evaluatePromoRule(ctx, svcCtx.DB, rule, params, userID, &currentUser, now)
+		if err != nil {
+			return nil, err
+		}
+		if !eligible {
+			continue
+		}
+
+		return &PromoResult{
+			Eligible:   true,
+			RuleID:     rule.Id,
+			RuleName:   rule.Name,
+			RuleType:   rule.Type,
+			PromoPrice: rule.PromoPrice,
+			ExpiresAt:  expiresAt,
+		}, nil
+	}
+
+	return result, nil
+}
+
+func isPromoRuleInTimeWindow(rule *promo.RuleWithPrice, now time.Time) bool {
+	if rule.StartTime != nil && !rule.StartTime.IsZero() && now.Before(*rule.StartTime) {
+		return false
+	}
+	if rule.EndTime != nil && !rule.EndTime.IsZero() && now.After(*rule.EndTime) {
+		return false
+	}
+	return true
+}
+
+func evaluatePromoRule(
+	ctx context.Context,
+	db *gorm.DB,
+	rule *promo.RuleWithPrice,
+	params promoRuleParams,
+	userID int64,
+	currentUser *user.User,
+	now time.Time,
+) (bool, time.Time, error) {
+	switch rule.Type {
+	case promo.RuleTypeNewUser:
+		return evaluateNewUserPromo(ctx, db, params, userID, currentUser, now)
+	case promo.RuleTypeInactiveUser:
+		return evaluateInactiveUserPromo(ctx, db, params, userID, promoRuleExpiresAt(rule), now)
+	case promo.RuleTypeCampaign:
+		return true, promoRuleExpiresAt(rule), nil
+	default:
+		return false, time.Time{}, nil
+	}
+}
+
+func evaluateNewUserPromo(
+	ctx context.Context,
+	db *gorm.DB,
+	params promoRuleParams,
+	userID int64,
+	currentUser *user.User,
+	now time.Time,
+) (bool, time.Time, error) {
+	if params.WindowHours <= 0 {
+		return false, time.Time{}, nil
+	}
+
+	if currentUser.Id == 0 {
+		if err := db.WithContext(ctx).Model(&user.User{}).Where("id = ?", userID).First(currentUser).Error; err != nil {
+			return false, time.Time{}, errors.Wrapf(xerr.NewErrCode(xerr.DatabaseQueryError), "query promo user failed")
+		}
+	}
+
+	expiresAt := currentUser.CreatedAt.Add(time.Duration(params.WindowHours) * time.Hour)
+	return now.Before(expiresAt), expiresAt, nil
+}
+
+func evaluateInactiveUserPromo(
+	ctx context.Context,
+	db *gorm.DB,
+	params promoRuleParams,
+	userID int64,
+	ruleExpiresAt time.Time,
+	now time.Time,
+) (bool, time.Time, error) {
+	if params.InactiveMonths <= 0 {
+		return false, time.Time{}, nil
+	}
+
+	var lastSub user.Subscribe
+	err := db.WithContext(ctx).
+		Model(&user.Subscribe{}).
+		Where("user_id = ?", userID).
+		Order("expire_time DESC").
+		Limit(1).
+		Take(&lastSub).Error
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return true, ruleExpiresAt, nil
+		}
+		return false, time.Time{}, errors.Wrapf(xerr.NewErrCode(xerr.DatabaseQueryError), "query promo inactive user subscription failed")
+	}
+
+	threshold := now.AddDate(0, -params.InactiveMonths, 0)
+	return lastSub.ExpireTime.Before(threshold) || lastSub.ExpireTime.Equal(threshold), ruleExpiresAt, nil
+}
+
+func promoRuleExpiresAt(rule *promo.RuleWithPrice) time.Time {
+	if rule != nil && rule.EndTime != nil {
+		return *rule.EndTime
+	}
+	return time.Time{}
+}

internal/logic/public/order/preCreateOrderLogic.go

@@ -2,7 +2,6 @@ package order
 
 import (
 	"context"
-	"math"
 
 	commonLogic "github.com/perfect-panel/server/internal/logic/common"
 	"github.com/perfect-panel/server/internal/model/order"
@@ -115,15 +114,28 @@ func (l *PreCreateOrderLogic) PreCreateOrder(req *types.PurchaseOrderRequest) (r
 		return nil, errors.Wrapf(xerr.NewErrCode(xerr.SubscribeNewUserOnly), "not a new user")
 	}
 
-	var discount float64 = 1
-	if len(newUserDiscount.Discounts) > 0 {
-		discount = getDiscount(newUserDiscount.Discounts, req.Quantity, newUserDiscount.EligibleForDiscount)
+	priceResult, err := calculatePurchasePrice(
+		l.ctx,
+		l.svcCtx,
+		u.Id,
+		targetSubscribeID,
+		sub.UnitPrice,
+		req.Quantity,
+		newUserDiscount.Discounts,
+		newUserDiscount.EligibleForDiscount,
+		!isSingleModeRenewal,
+	)
+	if err != nil {
+		l.Errorw("[PreCreateOrder] Promo price calculation error",
+			logger.Field("error", err.Error()),
+			logger.Field("user_id", u.Id),
+			logger.Field("subscribe_id", targetSubscribeID),
+		)
+		return nil, err
 	}
-	price := sub.UnitPrice * req.Quantity
-
-	amount := int64(math.Round(float64(price) * discount))
-	discountAmount := price - amount
-	var promoDiscount int64
+	price := priceResult.OriginalPrice
+	amount := priceResult.PayableBase
+	discountAmount := priceResult.DiscountAmount
 	var couponAmount int64
 	if req.Coupon != "" {
 		couponInfo, err := l.svcCtx.CouponModel.FindOneByCode(l.ctx, req.Coupon)
@@ -186,7 +198,7 @@ func (l *PreCreateOrderLogic) PreCreateOrder(req *types.PurchaseOrderRequest) (r
 		Price:          price,
 		Amount:         amount,
 		Discount:       discountAmount,
-		PromoDiscount:  promoDiscount,
+		PromoDiscount:  priceResult.PromoDiscount,
 		GiftAmount:     deductionAmount,
 		Coupon:         req.Coupon,
 		CouponDiscount: couponAmount,

internal/logic/public/order/promoPricing.go

@@ -0,0 +1,62 @@
+package order
+
+import (
+	"context"
+	"math"
+
+	commonLogic "github.com/perfect-panel/server/internal/logic/common"
+	"github.com/perfect-panel/server/internal/svc"
+	"github.com/perfect-panel/server/internal/types"
+)
+
+type orderPriceResult struct {
+	OriginalPrice  int64
+	PayableBase    int64
+	DiscountAmount int64
+	PromoRuleId    int64
+	PromoDiscount  int64
+	PromoPrice     int64
+}
+
+func calculatePurchasePrice(
+	ctx context.Context,
+	svcCtx *svc.ServiceContext,
+	userID int64,
+	subscribeID int64,
+	unitPrice int64,
+	quantity int64,
+	discounts []types.SubscribeDiscount,
+	eligibleForDiscount bool,
+	allowPromo bool,
+) (*orderPriceResult, error) {
+	originalPrice := unitPrice * quantity
+	result := &orderPriceResult{
+		OriginalPrice: originalPrice,
+		PayableBase:   originalPrice,
+	}
+
+	if allowPromo {
+		promoResult, err := commonLogic.EvaluatePromo(ctx, svcCtx, userID, subscribeID)
+		if err != nil {
+			return nil, err
+		}
+		if promoResult != nil && promoResult.Eligible && promoResult.PromoPrice < unitPrice {
+			result.PayableBase = promoResult.PromoPrice * quantity
+			result.PromoRuleId = promoResult.RuleID
+			result.PromoDiscount = originalPrice - result.PayableBase
+			result.PromoPrice = promoResult.PromoPrice
+			if result.PromoDiscount < 0 {
+				result.PromoDiscount = 0
+			}
+			return result, nil
+		}
+	}
+
+	discount := float64(1)
+	if len(discounts) > 0 {
+		discount = getDiscount(discounts, quantity, eligibleForDiscount)
+	}
+	result.PayableBase = int64(math.Round(float64(originalPrice) * discount))
+	result.DiscountAmount = originalPrice - result.PayableBase
+	return result, nil
+}

internal/logic/public/order/promoPricing_test.go

@@ -0,0 +1,113 @@
+package order
+
+import (
+	"context"
+	"testing"
+
+	"github.com/perfect-panel/server/internal/model/promo"
+	"github.com/perfect-panel/server/internal/svc"
+	"github.com/perfect-panel/server/internal/types"
+	"gorm.io/gorm"
+)
+
+type fakePromoModel struct {
+	rules []*promo.RuleWithPrice
+}
+
+func (m fakePromoModel) QueryEligibleRules(context.Context, int64) ([]*promo.RuleWithPrice, error) {
+	return m.rules, nil
+}
+
+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{
+			{
+				Rule: promo.Rule{
+					Id:      9,
+					Name:    "campaign",
+					Type:    promo.RuleTypeCampaign,
+					Enabled: true,
+				},
+				PromoPrice: 600,
+			},
+		}},
+	}
+
+	result, err := calculatePurchasePrice(
+		context.Background(),
+		svcCtx,
+		1,
+		2,
+		1000,
+		3,
+		[]types.SubscribeDiscount{{Quantity: 3, Discount: 50}},
+		true,
+		true,
+	)
+	if err != nil {
+		t.Fatalf("calculatePurchasePrice returned error: %v", err)
+	}
+
+	if result.OriginalPrice != 3000 {
+		t.Fatalf("OriginalPrice = %d, want 3000", result.OriginalPrice)
+	}
+	if result.PayableBase != 1800 {
+		t.Fatalf("PayableBase = %d, want 1800", result.PayableBase)
+	}
+	if result.DiscountAmount != 0 {
+		t.Fatalf("DiscountAmount = %d, want 0", result.DiscountAmount)
+	}
+	if result.PromoRuleId != 9 {
+		t.Fatalf("PromoRuleId = %d, want 9", result.PromoRuleId)
+	}
+	if result.PromoDiscount != 1200 {
+		t.Fatalf("PromoDiscount = %d, want 1200", result.PromoDiscount)
+	}
+}
+
+func TestCalculatePurchasePriceIgnoresInvalidPromoPrice(t *testing.T) {
+	svcCtx := &svc.ServiceContext{
+		DB: &gorm.DB{},
+		PromoModel: fakePromoModel{rules: []*promo.RuleWithPrice{
+			{
+				Rule: promo.Rule{
+					Id:      10,
+					Name:    "invalid campaign",
+					Type:    promo.RuleTypeCampaign,
+					Enabled: true,
+				},
+				PromoPrice: 1000,
+			},
+		}},
+	}
+
+	result, err := calculatePurchasePrice(
+		context.Background(),
+		svcCtx,
+		1,
+		2,
+		1000,
+		3,
+		[]types.SubscribeDiscount{{Quantity: 3, Discount: 50}},
+		true,
+		true,
+	)
+	if err != nil {
+		t.Fatalf("calculatePurchasePrice returned error: %v", err)
+	}
+
+	if result.PayableBase != 1500 {
+		t.Fatalf("PayableBase = %d, want 1500", result.PayableBase)
+	}
+	if result.DiscountAmount != 1500 {
+		t.Fatalf("DiscountAmount = %d, want 1500", result.DiscountAmount)
+	}
+	if result.PromoRuleId != 0 || result.PromoDiscount != 0 {
+		t.Fatalf("promo fields = (%d, %d), want (0, 0)", result.PromoRuleId, result.PromoDiscount)
+	}
+}

internal/logic/public/order/purchaseLogic.go

@@ -3,7 +3,6 @@ package order
 import (
 	"context"
 	"encoding/json"
-	"math"
 	"strings"
 	"time"
 
@@ -204,14 +203,28 @@ func (l *PurchaseLogic) Purchase(req *types.PurchaseOrderRequest) (resp *types.P
 		return nil, err
 	}
 
-	var discount float64 = 1
-	if len(newUserDiscount.Discounts) > 0 {
-		discount = getDiscount(newUserDiscount.Discounts, req.Quantity, newUserDiscount.EligibleForDiscount)
+	priceResult, err := calculatePurchasePrice(
+		l.ctx,
+		l.svcCtx,
+		u.Id,
+		targetSubscribeID,
+		sub.UnitPrice,
+		req.Quantity,
+		newUserDiscount.Discounts,
+		newUserDiscount.EligibleForDiscount,
+		orderType == 1,
+	)
+	if err != nil {
+		l.Errorw("[Purchase] Promo price calculation error",
+			logger.Field("error", err.Error()),
+			logger.Field("user_id", u.Id),
+			logger.Field("subscribe_id", targetSubscribeID),
+		)
+		return nil, err
 	}
-	price := sub.UnitPrice * req.Quantity
-	// discount amount
-	amount := int64(math.Round(float64(price) * discount))
-	discountAmount := price - amount
+	price := priceResult.OriginalPrice
+	amount := priceResult.PayableBase
+	discountAmount := priceResult.DiscountAmount
 
 	// Validate amount to prevent overflow
 	if amount > MaxOrderAmount {
@@ -306,6 +319,8 @@ func (l *PurchaseLogic) Purchase(req *types.PurchaseOrderRequest) (resp *types.P
 		Price:              price,
 		Amount:             amount,
 		Discount:           discountAmount,
+		PromoRuleId:        priceResult.PromoRuleId,
+		PromoDiscount:      priceResult.PromoDiscount,
 		GiftAmount:         deductionAmount,
 		Coupon:             req.Coupon,
 		CouponDiscount:     coupon,