diff --git a/database/entities/m_product_entity.go b/database/entities/m_product_entity.go
index 6252e47..cf47a36 100644
--- a/database/entities/m_product_entity.go
+++ b/database/entities/m_product_entity.go
@@ -1,7 +1,12 @@
 package entities
 
 import (
+	"fmt"
+	"strings"
+	"time"
+
 	"github.com/google/uuid"
+	"gorm.io/gorm"
 )
 
 type MProductEntity struct {
@@ -52,6 +57,7 @@ type MProductEntity struct {
 	UomToUom              MUomEntity                   `gorm:"foreignKey:UomToUomID;references:ID"`
 	CrossReferences       []MCrossReferenceEntity      `gorm:"foreignKey:ProductID;references:ID"`
 	InventoryTransactions []InventoryTransactionEntity `gorm:"foreignKey:ProductID;references:ID"`
+	InventoryStorages     []InventoryStorageEntity     `gorm:"foreignKey:ProductID;references:ID"`
 
 	FullAuditTrail
 }
@@ -59,3 +65,64 @@ type MProductEntity struct {
 func (MProductEntity) TableName() string {
 	return "m_products"
 }
+
+// GenerateRefNumberProduct generates a new reference number for a product
+func GenerateRefNumberProduct(db *gorm.DB, clientId string, categoryId string) (string, error) {
+	prefix := "PRD"
+
+	// Ambil nama client berdasarkan clientId
+	var client struct {
+		Name string
+	}
+	if err := db.Table("m_clients").Select("name").Where("id = ?", clientId).First(&client).Error; err != nil {
+		return "", fmt.Errorf("client not found")
+	}
+	if client.Name == "" {
+		return "", fmt.Errorf("client name is empty")
+	}
+
+	// Ambil search key kategori berdasarkan categoryId
+	var category struct {
+		SearchKey string
+	}
+	if err := db.Table("m_categories").Select("search_key").Where("id = ?", categoryId).First(&category).Error; err != nil {
+		return "", fmt.Errorf("category not found")
+	}
+	if category.SearchKey == "" {
+		return "", fmt.Errorf("category search key is empty")
+	}
+	categoryInitial := ""
+	lettersOnly := ""
+	for _, r := range category.SearchKey {
+		if (r >= 'A' && r <= 'Z') || (r >= 'a' && r <= 'z') {
+			lettersOnly += string(r)
+		}
+	}
+	if len(lettersOnly) > 0 {
+		categoryInitial = strings.ToUpper(lettersOnly)
+	}
+
+	// Ambil tahun dan bulan sekarang
+	now := time.Now()
+	period := now.Format("0601") // YYYYMM
+
+	// Cari sequence terakhir untuk client dan kategori di periode ini
+	var lastProduct MProductEntity
+	prefixQuery := fmt.Sprintf("%s-%s-%s", prefix, categoryInitial, period)
+	err := db.
+		Where("client_id = ? AND category_id = ? AND LEFT(ref_number, ?) = ?", clientId, categoryId, len(prefixQuery), prefixQuery).
+		Order("ref_number DESC").
+		First(&lastProduct).Error
+
+	seq := 1
+	if err == nil && lastProduct.RefNumber != "" {
+		parts := strings.Split(lastProduct.RefNumber, "-")
+		if len(parts) == 4 {
+			fmt.Sscanf(parts[3], "%d", &seq)
+			seq++
+		}
+	}
+
+	refNum := fmt.Sprintf("%s-%s-%s-%04d", prefix, categoryInitial, period, seq)
+	return refNum, nil
+}
diff --git a/modules/product/dto/product_dto.go b/modules/product/dto/product_dto.go
index 9389fd7..bbb4f36 100644
--- a/modules/product/dto/product_dto.go
+++ b/modules/product/dto/product_dto.go
@@ -34,7 +34,7 @@ var (
 type (
 	ProductCreateRequest struct {
 		Name         string `json:"name" binding:"required"`
-		RefNumber    string `json:"ref_number" binding:"required"`
+		// RefNumber    string `json:"ref_number" binding:"required"`
 		SKU          string `json:"sku" binding:"required"`
 		Description  string `json:"description"`
 		Status       string `json:"status" binding:"required"`
@@ -69,7 +69,7 @@ type (
 
 	ProductUpdateRequest struct {
 		Name           *string  `json:"name"`
-		RefNumber      *string  `json:"ref_number"`
+		// RefNumber      *string  `json:"ref_number"`
 		SKU            *string  `json:"sku"`
 		Description    *string  `json:"description"`
 		Status         *string  `json:"status"`
@@ -153,7 +153,14 @@ type (
 	}
 
 	ProductInventoryTransactionResponse struct {
-		ID              string `json:"id"`
-		TransactionType string `json:"transaction_type"`
+		ID                  string  `json:"id"`
+		TransactionDate     string  `json:"transaction_date"`
+		TransactionType     string  `json:"transaction_type"`
+		TransactionQuantity float64 `json:"transaction_quantity"`
+		Lot                 string  `json:"lot"`
+		Locater             string  `json:"locater"`
+		InvReceiptRef       string  `json:"inv_receipt_ref,omitempty"`
+		InvIssueRef         string  `json:"inv_issue_ref,omitempty"`
+		InvMoveRef          string  `json:"inv_move_ref,omitempty"`
 	}
 )
diff --git a/modules/product/repository/product_repository.go b/modules/product/repository/product_repository.go
index b25b8ee..13f8e90 100644
--- a/modules/product/repository/product_repository.go
+++ b/modules/product/repository/product_repository.go
@@ -116,13 +116,19 @@ func (r *productRepository) GetById(ctx context.Context, tx *gorm.DB, productId
 		Preload("UomToUom").
 		Preload("CrossReferences").
 		Preload("CrossReferences.Vendor").
-		Preload("InvTransactions").
-		Preload("InvTransactions.Product").
-		Preload("InvTransactions.Client").
-		Preload("InvTransactions.Aisle").
-		Preload("InvTransactions.InvReceipt").
-		Preload("InvTransactions.InvIssue").
-		Preload("InvTransactions.InvMove").
+		Preload("InventoryStorages").
+		Preload("InventoryTransactions").
+		Preload("InventoryTransactions.Client").
+		Preload("InventoryTransactions.Aisle").
+		Preload("InventoryTransactions.InvReceipt").
+		Preload("InventoryTransactions.InvReceipt.ReceiptLines").
+		Preload("InventoryTransactions.InvReceipt.ReceiptLines.Product").
+		Preload("InventoryTransactions.InvIssue").
+		Preload("InventoryTransactions.InvIssue.IssueLines").
+		Preload("InventoryTransactions.InvIssue.IssueLines.Product").
+		Preload("InventoryTransactions.InvMove").
+		Preload("InventoryTransactions.InvMove.MovementLines").
+		Preload("InventoryTransactions.InvMove.MovementLines.Product").
 		First(&product, "id = ?", productId).Error; err != nil {
 		return product, err
 	}
diff --git a/modules/product/service/product_service.go b/modules/product/service/product_service.go
index 5554654..704fa1a 100644
--- a/modules/product/service/product_service.go
+++ b/modules/product/service/product_service.go
@@ -8,7 +8,9 @@ import (
 	"github.com/Caknoooo/go-gin-clean-starter/modules/product/query"
 	"github.com/Caknoooo/go-gin-clean-starter/modules/product/repository"
 	pkgdto "github.com/Caknoooo/go-gin-clean-starter/pkg/dto"
+	"github.com/Caknoooo/go-gin-clean-starter/pkg/utils"
 	"github.com/google/uuid"
+	"github.com/sirupsen/logrus"
 	"gorm.io/gorm"
 )
 
@@ -81,9 +83,14 @@ func (s *productService) Create(ctx context.Context, req dto.ProductCreateReques
 			tx.Rollback()
 		}
 	}()
+	refNumber, err := entities.GenerateRefNumberProduct(tx, req.ClientID, *req.CategoryID)
+	if err != nil {
+		tx.Rollback()
+		return dto.ProductResponse{}, err
+	}
 	product := entities.MProductEntity{
 		Name:         req.Name,
-		RefNumber:    req.RefNumber,
+		RefNumber:    refNumber,
 		SKU:          req.SKU,
 		Description:  req.Description,
 		Status:       req.Status,
@@ -175,9 +182,6 @@ func (s *productService) Update(ctx context.Context, req dto.ProductUpdateReques
 	if req.Name != nil {
 		product.Name = *req.Name
 	}
-	if req.RefNumber != nil {
-		product.RefNumber = *req.RefNumber
-	}
 	if req.SKU != nil {
 		product.SKU = *req.SKU
 	}
@@ -331,6 +335,70 @@ func mapProductToResponse(product entities.MProductEntity) dto.ProductResponse {
 		})
 	}
 
+	logrus.Infof("Inventory Transactions Count: %d", len(product.InventoryTransactions))
+	invTransactions := make([]dto.ProductInventoryTransactionResponse, 0, len(product.InventoryTransactions))
+	for _, it := range product.InventoryTransactions {
+		var transactionQuantity float64
+		var lot, locater, invReceiptRef, invIssueRef, invMoveRef string
+		var transactionDate string
+
+		// Receipt
+		if it.InvReceipt.ID != uuid.Nil {
+			invReceiptRef = it.InvReceipt.ReferenceNumber
+			transactionDate = utils.DateTimeToString(it.TransactionDate)
+			// Cari line yang sesuai product
+			for _, line := range it.InvReceipt.ReceiptLines {
+				if line.ProductID == it.ProductID {
+					transactionQuantity = line.Quantity
+					lot = line.BatchNumber
+					// Jika ada field lokasi, isi di sini
+					// locater = line.Locater
+					break
+				}
+			}
+		}
+
+		// Issue
+		if it.InvIssue.ID != uuid.Nil {
+			invIssueRef = it.InvIssue.DocumentNumber
+			transactionDate = utils.DateTimeToString(it.TransactionDate)
+			for _, line := range it.InvIssue.IssueLines {
+				if line.ProductID == it.ProductID {
+					transactionQuantity = line.IssuedQuantity
+					// lot = line.BatchNumber
+					// locater = line.Locater
+					break
+				}
+			}
+		}
+
+		// Move
+		if it.InvMove.ID != uuid.Nil {
+			invMoveRef = it.InvMove.MovementNumber
+			transactionDate = utils.DateTimeToString(it.TransactionDate)
+			for _, line := range it.InvMove.MovementLines {
+				if line.ProductID == it.ProductID {
+					transactionQuantity = line.MovedQuantity
+					// lot = line.BatchNumber
+					// locater = line.Locater
+					break
+				}
+			}
+		}
+
+		invTransactions = append(invTransactions, dto.ProductInventoryTransactionResponse{
+			ID:                  it.ID.String(),
+			TransactionDate:     transactionDate,
+			TransactionType:     it.TransactionType,
+			TransactionQuantity: transactionQuantity,
+			Lot:                 lot,
+			Locater:             locater,
+			InvReceiptRef:       invReceiptRef,
+			InvIssueRef:         invIssueRef,
+			InvMoveRef:          invMoveRef,
+		})
+	}
+
 	return dto.ProductResponse{
 		ID:             product.ID.String(),
 		Name:           product.Name,
@@ -396,5 +464,6 @@ func mapProductToResponse(product entities.MProductEntity) dto.ProductResponse {
 			Name: product.UomToUom.Name,
 		},
 		CrossReferences: crossRefs,
+		InvTransactions: invTransactions,
 	}
 }