退款纠纷分配

backend/internal/modules/dispute/arbitration.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"log"
+	"math"
 	"time"
 
 	"hfb_sys/backend/internal/listingstatus"
@@ -246,7 +247,11 @@ func buildArbitrationSettlement(order model.RentalOrder, req ArbitrateRequest, r
 		addRenterRefund(req.AmountCent, "仲裁部分退款")
 		// 部分退款为合并金额，无法精确拆分租金/押金，按押金优先归类以便暂扣。
 		settlement.RenterDepositRefundCent = money.MinCent(req.AmountCent, depositAmountCent)
-		addOwnerIncome(money.MinCent(totalCent-req.AmountCent, ownerRentAmountCent+depositAmountCent), "仲裁剩余金额结算给号主")
+		// 号主仅拿「未退租金中的号主份额 + 未退押金」，平台加价按未退租金比例预留，避免整笔剩余进号主。
+		addOwnerIncome(
+			partialRefundOwnerIncomeCent(rentAmountCent, ownerRentAmountCent, depositAmountCent, req.AmountCent),
+			"仲裁剩余金额结算给号主",
+		)
 	case "release_deposit":
 		addOwnerIncome(ownerRentAmountCent, "仲裁确认订单金额结算给号主")
 		addRenterRefund(depositAmountCent, "仲裁释放押金给租客")
@@ -273,6 +278,66 @@ func buildArbitrationSettlement(order model.RentalOrder, req ArbitrateRequest, r
 	return settlement, nil
 }
 
+// partialRefundOwnerIncomeCent 计算部分退款后号主应得。
+// 退款优先冲押金，其余冲租金；未退租金按预收结构拆分：
+// 平台费 = 租客租金 − 号主租金，并按 未退租金/预收租金 比例预留，剩余才归号主。
+// 这样可避免「剩余金额整笔给号主」把平台加价分给用户。
+func partialRefundOwnerIncomeCent(rentAmountCent, ownerRentAmountCent, depositAmountCent, renterRefundCent int64) int64 {
+	if renterRefundCent < 0 {
+		renterRefundCent = 0
+	}
+	totalCent := rentAmountCent + depositAmountCent
+	if renterRefundCent > totalCent {
+		renterRefundCent = totalCent
+	}
+	if ownerRentAmountCent < 0 {
+		ownerRentAmountCent = 0
+	}
+	if ownerRentAmountCent > rentAmountCent {
+		ownerRentAmountCent = rentAmountCent
+	}
+
+	// 退款优先视为押金退还，其余视为租金退还（与 RenterDepositRefundCent 归类一致）
+	depositRefunded := money.MinCent(renterRefundCent, depositAmountCent)
+	rentRefunded := renterRefundCent - depositRefunded
+	rentLeft := rentAmountCent - rentRefunded
+	if rentLeft < 0 {
+		rentLeft = 0
+	}
+	depositLeft := depositAmountCent - depositRefunded
+
+	platformFeeCent := rentAmountCent - ownerRentAmountCent
+	if platformFeeCent < 0 {
+		platformFeeCent = 0
+	}
+
+	// 按未退租金占比预留平台费
+	platformKeepCent := int64(0)
+	if rentAmountCent > 0 && rentLeft > 0 && platformFeeCent > 0 {
+		platformKeepCent = int64(math.Round(float64(platformFeeCent) * float64(rentLeft) / float64(rentAmountCent)))
+		platformKeepCent = money.MinCent(platformKeepCent, rentLeft)
+		platformKeepCent = money.MinCent(platformKeepCent, platformFeeCent)
+	}
+
+	ownerFromRent := rentLeft - platformKeepCent
+	if ownerFromRent > ownerRentAmountCent {
+		ownerFromRent = ownerRentAmountCent
+	}
+	if ownerFromRent < 0 {
+		ownerFromRent = 0
+	}
+
+	ownerIncome := ownerFromRent + depositLeft
+	remaining := totalCent - renterRefundCent
+	if ownerIncome > remaining {
+		ownerIncome = remaining
+	}
+	if ownerIncome < 0 {
+		return 0
+	}
+	return ownerIncome
+}
+
 func (r *Repository) prepareRefund(order *model.RentalOrder, amountCent int64, bizType string, remark string) (*refundAction, error) {
 	if amountCent <= 0 {
 		return nil, nil

backend/internal/modules/dispute/repository_test.go

@@ -261,3 +261,78 @@ func TestBuildArbitrationHandoffContent(t *testing.T) {
 		}
 	}
 }
+
+// 复现线上单：预收 94.7（号主 66.7 + 平台 28），部分退 50 时，号主不应吃掉平台加价。
+func TestPartialRefundReservesPlatformFee(t *testing.T) {
+	order := model.RentalOrder{
+		ID:                  30,
+		OrderNo:             "RO-ARBIT-PARTIAL-001",
+		RenterID:            9233,
+		OwnerID:             7463,
+		RentAmountCent:      9470,
+		OwnerRentAmountCent: 6670,
+		DepositAmountCent:   0,
+	}
+
+	settlement, err := buildArbitrationSettlement(order, ArbitrateRequest{
+		Result:     "partial_refund",
+		AmountCent: 5000,
+		Remark:     "没打完 号主登录不上",
+	}, 0)
+	if err != nil {
+		t.Fatalf("buildArbitrationSettlement() error = %v", err)
+	}
+	if settlement.RenterRefundAmountCent != 5000 {
+		t.Fatalf("RenterRefundAmountCent = %d, want 5000", settlement.RenterRefundAmountCent)
+	}
+
+	// 未退租金 44.7：平台按比例预留 round(28 * 44.7/94.7)=13.22 → 号主 31.48
+	wantOwner := partialRefundOwnerIncomeCent(9470, 6670, 0, 5000)
+	if settlement.OwnerIncomeAmountCent != wantOwner {
+		t.Fatalf("OwnerIncomeAmountCent = %d, want %d", settlement.OwnerIncomeAmountCent, wantOwner)
+	}
+	if settlement.OwnerIncomeAmountCent >= 4470 {
+		t.Fatalf("号主收入 %d 不应吞掉整笔剩余 4470（含平台费）", settlement.OwnerIncomeAmountCent)
+	}
+	platformKeep := 9470 - settlement.RenterRefundAmountCent - settlement.OwnerIncomeAmountCent
+	if platformKeep <= 0 {
+		t.Fatalf("平台留存 = %d, 部分退款后应保留平台加价份额", platformKeep)
+	}
+}
+
+func TestPartialRefundFullRentRetainedGivesOwnerFullOwnerRent(t *testing.T) {
+	// 只退押金：号主拿满预收号主租金，平台留满预收平台费
+	order := model.RentalOrder{
+		RentAmountCent:      9470,
+		OwnerRentAmountCent: 6670,
+		DepositAmountCent:   20000,
+	}
+	settlement, err := buildArbitrationSettlement(order, ArbitrateRequest{
+		Result:     "partial_refund",
+		AmountCent: 20000,
+	}, 0)
+	if err != nil {
+		t.Fatalf("buildArbitrationSettlement() error = %v", err)
+	}
+	if settlement.OwnerIncomeAmountCent != 6670 {
+		t.Fatalf("OwnerIncomeAmountCent = %d, want 6670", settlement.OwnerIncomeAmountCent)
+	}
+	if settlement.RenterRefundAmountCent != 20000 {
+		t.Fatalf("RenterRefundAmountCent = %d, want 20000", settlement.RenterRefundAmountCent)
+	}
+	platformKeep := 9470 + 20000 - settlement.RenterRefundAmountCent - settlement.OwnerIncomeAmountCent
+	if platformKeep != 2800 {
+		t.Fatalf("platformKeep = %d, want 2800", platformKeep)
+	}
+}
+
+func TestPartialRefundOwnerIncomeCentUnit(t *testing.T) {
+	// 无平台费时，未退租金全部给号主
+	if got := partialRefundOwnerIncomeCent(10000, 10000, 0, 3000); got != 7000 {
+		t.Fatalf("no platform fee: got %d, want 7000", got)
+	}
+	// 全额退：号主 0
+	if got := partialRefundOwnerIncomeCent(9470, 6670, 0, 9470); got != 0 {
+		t.Fatalf("full refund: got %d, want 0", got)
+	}
+}