update unique letter number

internal/processor/letter_outgoing_processor.go

@@ -17,6 +17,7 @@ import (
 type LetterOutgoingProcessor interface {
 	CreateOutgoingLetter(ctx context.Context, letter *entities.LetterOutgoing, attachments []entities.LetterOutgoingAttachment, userID, departmentID uuid.UUID) error
 	GetOutgoingLetterByID(ctx context.Context, id uuid.UUID) (*entities.LetterOutgoing, error)
+	GetOutgoingLetterByReferenceNumber(ctx context.Context, referenceNumber *string) (*entities.LetterOutgoing, error)
 	ListOutgoingLetters(ctx context.Context, filter repository.ListOutgoingLettersFilter, limit, offset int) ([]entities.LetterOutgoing, int64, error)
 	SearchOutgoingLetters(ctx context.Context, filters map[string]interface{}, page, limit int, sortBy, sortOrder string) ([]entities.LetterOutgoing, int64, error)
 	UpdateOutgoingLetter(ctx context.Context, letter *entities.LetterOutgoing, userID uuid.UUID) error
@@ -110,6 +111,11 @@ func NewLetterOutgoingProcessor(
 }
 
 func (p *LetterOutgoingProcessorImpl) CreateOutgoingLetter(ctx context.Context, letter *entities.LetterOutgoing, attachments []entities.LetterOutgoingAttachment, userID, departmentID uuid.UUID) error {
+	existingOutgoing, err := p.letterRepo.GetByReferenceNumber(ctx, letter.ReferenceNumber)
+	if err == nil && existingOutgoing != nil {
+		return fmt.Errorf("surat dengan nomor %s sudah ada", *letter.ReferenceNumber)
+	}
+
 	return p.txManager.WithTransaction(ctx, func(txCtx context.Context) error {
 		// Step 1: Assign approval flow from department if not provided
 		if err := p.assignApprovalFlowFromDepartment(txCtx, letter, departmentID); err != nil {
@@ -148,6 +154,10 @@ func (p *LetterOutgoingProcessorImpl) CreateOutgoingLetter(ctx context.Context,
 	})
 }
 
+func (p *LetterOutgoingProcessorImpl) GetOutgoingLetterByReferenceNumber(ctx context.Context, referenceNumber *string) (*entities.LetterOutgoing, error) {
+	return p.letterRepo.GetByReferenceNumber(ctx, referenceNumber)
+}
+
 func (p *LetterOutgoingProcessorImpl) assignApprovalFlowFromDepartment(ctx context.Context, letter *entities.LetterOutgoing, departmentID uuid.UUID) error {
 	if letter.ApprovalFlowID != nil || departmentID == uuid.Nil {
 		return nil

internal/processor/letter_processor.go

@@ -60,6 +60,11 @@ func NewLetterProcessor(letterRepo *repository.LetterIncomingRepository, attachR
 func (p *LetterProcessorImpl) CreateIncomingLetter(ctx context.Context, req *contract.CreateIncomingLetterRequest) (*contract.IncomingLetterResponse, error) {
 	userID := appcontext.FromGinContext(ctx).UserID
 
+	existingIncoming, err := p.letterRepo.GetByReferenceNumber(ctx, req.ReferenceNumber)
+	if err == nil && existingIncoming != nil {
+		return nil, fmt.Errorf("surat dengan nomor %s sudah ada", *req.ReferenceNumber)
+	}
+
 	letterType := entities.LetterIncomingTypeUtama
 	if req.Type == "TEMBUSAN" {
 		letterType = entities.LetterIncomingTypeTembusan

internal/repository/letter_outgoing_repository.go

@@ -41,6 +41,25 @@ func (r *LetterOutgoingRepository) Get(ctx context.Context, id uuid.UUID) (*enti
 	return &e, nil
 }
 
+func (r *LetterOutgoingRepository) GetByReferenceNumber(ctx context.Context, refNumber *string) (*entities.LetterOutgoing, error) {
+	db := DBFromContext(ctx, r.db)
+	var e entities.LetterOutgoing
+	if err := db.WithContext(ctx).
+		Preload("Priority").
+		Preload("ReceiverInstitution").
+		Preload("Creator").
+		Preload("ApprovalFlow").
+		Preload("Recipients").
+		Preload("Attachments").
+		Preload("Approvals.Step").
+		Preload("Approvals.Approver").
+		Where("reference_number = ? AND deleted_at IS NULL", refNumber).
+		First(&e).Error; err != nil {
+		return nil, err
+	}
+	return &e, nil
+}
+
 func (r *LetterOutgoingRepository) Update(ctx context.Context, e *entities.LetterOutgoing) error {
 	db := DBFromContext(ctx, r.db)
 	return db.WithContext(ctx).Model(&entities.LetterOutgoing{}).Where("id = ? AND deleted_at IS NULL", e.ID).Updates(e).Error

internal/repository/letter_repository.go

@@ -29,6 +29,17 @@ func (r *LetterIncomingRepository) Get(ctx context.Context, id uuid.UUID) (*enti
 	return &e, nil
 }
 
+func (r *LetterIncomingRepository) GetByReferenceNumber(ctx context.Context, refNumber *string) (*entities.LetterIncoming, error) {
+	db := DBFromContext(ctx, r.db)
+	var e entities.LetterIncoming
+	if err := db.WithContext(ctx).
+		Where("reference_number = ? AND deleted_at IS NULL", refNumber).
+		First(&e).Error; err != nil {
+		return nil, err
+	}
+	return &e, nil
+}
+
 func (r *LetterIncomingRepository) GetByID(ctx context.Context, id uuid.UUID) (*entities.LetterIncoming, error) {
 	return r.Get(ctx, id)
 }

internal/service/letter_outgoing_service.go

@@ -94,6 +94,12 @@ func (s *LetterOutgoingServiceImpl) CreateOutgoingLetter(ctx context.Context, re
 	departmentID := getDepartmentIDFromContext(ctx)
 	userID := getUserIDFromContext(ctx)
 
+	existingOutgoing, err := s.processor.GetOutgoingLetterByReferenceNumber(ctx, req.ReferenceNumber)
+
+	if err == nil && existingOutgoing != nil {
+		return nil, fmt.Errorf("surat dengan nomor %s sudah ada", *req.ReferenceNumber)
+	}
+
 	// Create letter entity
 	letter := &entities.LetterOutgoing{
 		Subject:               req.Subject,
@@ -125,7 +131,7 @@ func (s *LetterOutgoingServiceImpl) CreateOutgoingLetter(ctx context.Context, re
 	}
 
 	// Execute creation with transaction in service layer
-	err := s.txManager.WithTransaction(ctx, func(txCtx context.Context) error {
+	err = s.txManager.WithTransaction(ctx, func(txCtx context.Context) error {
 		// Step 1: Validate letter
 		if err := s.validationProcessor.ValidateCreateOutgoingLetter(txCtx, letter); err != nil {
 			return err