Merge pull request #1439 from touwaeriol/feat/redeem-negative-value

feat(redeem): support negative values for refund/deduction

backend/internal/handler/admin/redeem_handler.go

@@ -35,9 +35,9 @@ func NewRedeemHandler(adminService service.AdminService, redeemService *service.
 type GenerateRedeemCodesRequest struct {
 	Count        int     `json:"count" binding:"required,min=1,max=100"`
 	Type         string  `json:"type" binding:"required,oneof=balance concurrency subscription invitation"`
-	Value        float64 `json:"value" binding:"min=0"`
-	GroupID      *int64  `json:"group_id"`                                    // 订阅类型必填
-	ValidityDays int     `json:"validity_days" binding:"omitempty,max=36500"` // 订阅类型使用，默认30天，最大100年
+	Value        float64 `json:"value"`
+	GroupID      *int64  `json:"group_id"`      // 订阅类型必填
+	ValidityDays int     `json:"validity_days"` // 订阅类型使用，正数增加/负数退款扣减
 }
 
 // CreateAndRedeemCodeRequest represents creating a fixed code and redeeming it for a target user.
@@ -45,10 +45,10 @@ type GenerateRedeemCodesRequest struct {
 type CreateAndRedeemCodeRequest struct {
 	Code         string  `json:"code" binding:"required,min=3,max=128"`
 	Type         string  `json:"type" binding:"omitempty,oneof=balance concurrency subscription invitation"` // 不传时默认 balance（向后兼容）
-	Value        float64 `json:"value" binding:"required,gt=0"`
+	Value        float64 `json:"value" binding:"required"`
 	UserID       int64   `json:"user_id" binding:"required,gt=0"`
-	GroupID      *int64  `json:"group_id"`                                    // subscription 类型必填
-	ValidityDays int     `json:"validity_days" binding:"omitempty,max=36500"` // subscription 类型必填，>0
+	GroupID      *int64  `json:"group_id"`      // subscription 类型必填
+	ValidityDays int     `json:"validity_days"` // subscription 类型：正数增加，负数退款扣减
 	Notes        string  `json:"notes"`
 }
 
@@ -150,8 +150,8 @@ func (h *RedeemHandler) CreateAndRedeem(c *gin.Context) {
 			response.BadRequest(c, "group_id is required for subscription type")
 			return
 		}
-		if req.ValidityDays <= 0 {
-			response.BadRequest(c, "validity_days must be greater than 0 for subscription type")
+		if req.ValidityDays == 0 {
+			response.BadRequest(c, "validity_days must not be zero for subscription type")
 			return
 		}
 	}

backend/internal/handler/admin/redeem_handler_test.go

@@ -76,32 +76,38 @@ func TestCreateAndRedeem_SubscriptionRequiresGroupID(t *testing.T) {
 	assert.Equal(t, http.StatusBadRequest, code)
 }
 
-func TestCreateAndRedeem_SubscriptionRequiresPositiveValidityDays(t *testing.T) {
+func TestCreateAndRedeem_SubscriptionRequiresNonZeroValidityDays(t *testing.T) {
 	groupID := int64(5)
 	h := newCreateAndRedeemHandler()
 
-	cases := []struct {
-		name         string
-		validityDays int
-	}{
-		{"zero", 0},
-		{"negative", -1},
-	}
-
-	for _, tc := range cases {
-		t.Run(tc.name, func(t *testing.T) {
-			code := postCreateAndRedeemValidation(t, h, map[string]any{
-				"code":          "test-sub-bad-days-" + tc.name,
-				"type":          "subscription",
-				"value":         29.9,
-				"user_id":       1,
-				"group_id":      groupID,
-				"validity_days": tc.validityDays,
-			})
-
-			assert.Equal(t, http.StatusBadRequest, code)
+	// zero should be rejected
+	t.Run("zero", func(t *testing.T) {
+		code := postCreateAndRedeemValidation(t, h, map[string]any{
+			"code":          "test-sub-bad-days-zero",
+			"type":          "subscription",
+			"value":         29.9,
+			"user_id":       1,
+			"group_id":      groupID,
+			"validity_days": 0,
 		})
-	}
+
+		assert.Equal(t, http.StatusBadRequest, code)
+	})
+
+	// negative should pass validation (used for refund/reduction)
+	t.Run("negative_passes_validation", func(t *testing.T) {
+		code := postCreateAndRedeemValidation(t, h, map[string]any{
+			"code":          "test-sub-negative-days",
+			"type":          "subscription",
+			"value":         29.9,
+			"user_id":       1,
+			"group_id":      groupID,
+			"validity_days": -7,
+		})
+
+		assert.NotEqual(t, http.StatusBadRequest, code,
+			"negative validity_days should pass validation for refund")
+	})
 }
 
 func TestCreateAndRedeem_SubscriptionValidParamsPassValidation(t *testing.T) {