fix(订单): 修复折扣计算问题并添加四舍五入处理

统一处理百分比和系数两种折扣输入方式，增加边界保护
在金额计算中使用math.Round进行四舍五入处理
添加相关单元测试确保计算准确性

internal/logic/public/order/calculateCoupon.go

@@ -1,13 +1,14 @@
 package order
 
 import (
-	"github.com/perfect-panel/server/internal/model/coupon"
+    "math"
+    "github.com/perfect-panel/server/internal/model/coupon"
 )
 
 func calculateCoupon(amount int64, couponInfo *coupon.Coupon) int64 {
-	if couponInfo.Type == 1 {
-		return int64(float64(amount) * (float64(couponInfo.Discount) / float64(100)))
-	} else {
-		return min(couponInfo.Discount, amount)
-	}
+    if couponInfo.Type == 1 {
+        return int64(math.Round(float64(amount) * (float64(couponInfo.Discount) / float64(100))))
+    } else {
+        return min(couponInfo.Discount, amount)
+    }
 }

internal/logic/public/order/calculateFee.go

@@ -1,6 +1,9 @@
 package order
 
-import "github.com/perfect-panel/server/internal/model/payment"
+import (
+    "math"
+    "github.com/perfect-panel/server/internal/model/payment"
+)
 
 func calculateFee(amount int64, config *payment.Payment) int64 {
 	var fee float64
@@ -16,5 +19,5 @@ func calculateFee(amount int64, config *payment.Payment) int64 {
 	case 3:
 		fee = float64(amount)*(float64(config.FeePercent)/float64(100)) + float64(config.FeeAmount)
 	}
-	return int64(fee)
+    return int64(math.Round(fee))
 }

internal/logic/public/order/calculate_coupon_test.go

@@ -0,0 +1,31 @@
+package order
+
+import (
+    "testing"
+    "github.com/perfect-panel/server/internal/model/coupon"
+)
+
+func TestCalculateCoupon_Percent(t *testing.T) {
+    c := &coupon.Coupon{Type: 1, Discount: 10}
+    got := calculateCoupon(1000, c)
+    if got != 100 {
+        t.Fatalf("percent coupon expected 100, got %d", got)
+    }
+}
+
+func TestCalculateCoupon_PercentRounding(t *testing.T) {
+    c := &coupon.Coupon{Type: 1, Discount: 10}
+    got := calculateCoupon(999, c) // 999*10% = 99.9 → round to 100
+    if got != 100 {
+        t.Fatalf("percent coupon rounding expected 100, got %d", got)
+    }
+}
+
+func TestCalculateCoupon_FixedCap(t *testing.T) {
+    c := &coupon.Coupon{Type: 2, Discount: 300}
+    got := calculateCoupon(200, c)
+    if got != 200 {
+        t.Fatalf("fixed coupon capped by amount expected 200, got %d", got)
+    }
+}
+

internal/logic/public/order/calculate_fee_test.go

@@ -0,0 +1,35 @@
+package order
+
+import (
+    "testing"
+    "github.com/perfect-panel/server/internal/model/payment"
+)
+
+func TestCalculateFee_Percent(t *testing.T) {
+    p := &payment.Payment{FeeMode: 1, FeePercent: 5}
+    if calculateFee(1000, p) != 50 {
+        t.Fatal("fee percent 5% of 1000 should be 50")
+    }
+}
+
+func TestCalculateFee_PercentRounding(t *testing.T) {
+    p := &payment.Payment{FeeMode: 1, FeePercent: 5}
+    if calculateFee(999, p) != 50 { // 999*5% = 49.95 → round to 50
+        t.Fatal("fee percent 5% of 999 should round to 50")
+    }
+}
+
+func TestCalculateFee_Fixed(t *testing.T) {
+    p := &payment.Payment{FeeMode: 2, FeeAmount: 300}
+    if calculateFee(1000, p) != 300 {
+        t.Fatal("fixed fee 300 should be 300")
+    }
+}
+
+func TestCalculateFee_Mixed(t *testing.T) {
+    p := &payment.Payment{FeeMode: 3, FeePercent: 10, FeeAmount: 100}
+    if calculateFee(1000, p) != 200 {
+        t.Fatal("mixed fee 10% + 100 of 1000 should be 200")
+    }
+}
+

internal/logic/public/order/getDiscount.go

@@ -6,13 +6,20 @@ import "github.com/perfect-panel/server/internal/types"
 // 参数：discounts 折扣规则列表（数量阈值 + 折扣倍数）；inputMonths 购买时长
 // 返回：最终价格倍数（如 0.95 表示按 95% 计价）
 func getDiscount(discounts []types.SubscribeDiscount, inputMonths int64) float64 {
-	var finalDiscount float64 = 1.0
+    var finalDiscount float64 = 1.0
 
-	for _, discount := range discounts {
-		if inputMonths >= discount.Quantity && discount.Discount < finalDiscount {
-			finalDiscount = discount.Discount
-		}
-	}
+    for _, d := range discounts {
+        val := d.Discount
+        if val > 1 && val <= 100 {
+            val = val / 100.0
+        }
+        if val < 0 {
+            val = 0
+        }
+        if inputMonths >= d.Quantity && val < finalDiscount {
+            finalDiscount = val
+        }
+    }
 
-	return finalDiscount
+    return finalDiscount
 }

internal/logic/public/order/get_discount_test.go

@@ -0,0 +1,31 @@
+package order
+
+import (
+    "testing"
+    "github.com/perfect-panel/server/internal/types"
+)
+
+func TestGetDiscount_Coefficient(t *testing.T) {
+    discounts := []types.SubscribeDiscount{{Quantity: 7, Discount: 0.95}}
+    got := getDiscount(discounts, 7)
+    if got != 0.95 {
+        t.Fatalf("expected 0.95, got %v", got)
+    }
+}
+
+func TestGetDiscount_Percentage(t *testing.T) {
+    discounts := []types.SubscribeDiscount{{Quantity: 7, Discount: 95}}
+    got := getDiscount(discounts, 7)
+    if got != 0.95 {
+        t.Fatalf("expected 0.95 from 95%%, got %v", got)
+    }
+}
+
+func TestGetDiscount_InvalidOver100(t *testing.T) {
+    discounts := []types.SubscribeDiscount{{Quantity: 7, Discount: 120}}
+    got := getDiscount(discounts, 7)
+    if got != 1.0 {
+        t.Fatalf("expected 1.0 when invalid >100, got %v", got)
+    }
+}
+

internal/logic/public/order/preCreateOrderLogic.go

@@ -3,6 +3,7 @@ package order
 import (
 	"context"
 	"encoding/json"
+	"math"
 
 	"github.com/perfect-panel/server/internal/model/order"
 	"github.com/perfect-panel/server/pkg/tool"
@@ -63,7 +64,7 @@ func (l *PreCreateOrderLogic) PreCreateOrder(req *types.PurchaseOrderRequest) (r
 	}
 	price := sub.UnitPrice * req.Quantity
 
-	amount := int64(float64(price) * discount)
+    amount := int64(math.Round(float64(price) * discount))
 	discountAmount := price - amount
 	var couponAmount int64
 	if req.Coupon != "" {

internal/logic/public/order/purchaseLogic.go

@@ -3,6 +3,7 @@ package order
 import (
 	"context"
 	"encoding/json"
+	"math"
 	"time"
 
 	"github.com/perfect-panel/server/internal/model/log"
@@ -102,7 +103,7 @@ func (l *PurchaseLogic) Purchase(req *types.PurchaseOrderRequest) (resp *types.P
 	}
 	price := sub.UnitPrice * req.Quantity
 	// discount amount
-	amount := int64(float64(price) * discount)
+    amount := int64(math.Round(float64(price) * discount))
 	discountAmount := price - amount
 	var coupon int64 = 0
 	// Calculate the coupon deduction