feat[BE-127]: Createing transfer laying create one, approvals, get one, get all, update, delete, but Still unfinished

internal/modules/production/transfer_layings/services/transfer_laying.service.go

@@ -1,10 +1,17 @@
 package service
 
 import (
+	"context"
 	"errors"
+	"fmt"
+	"strings"
+	"time"
 
-	common "gitlab.com/mbugroup/lti-api.git/internal/common/service"
+	commonRepo "gitlab.com/mbugroup/lti-api.git/internal/common/repository"
+	commonSvc "gitlab.com/mbugroup/lti-api.git/internal/common/service"
 	entity "gitlab.com/mbugroup/lti-api.git/internal/entities"
+	rInventory "gitlab.com/mbugroup/lti-api.git/internal/modules/inventory/product-warehouses/repositories"
+	rWarehouse "gitlab.com/mbugroup/lti-api.git/internal/modules/master/warehouses/repositories"
 	ProjectFlockRepository "gitlab.com/mbugroup/lti-api.git/internal/modules/production/project_flocks/repositories"
 	repository "gitlab.com/mbugroup/lti-api.git/internal/modules/production/transfer_layings/repositories"
 	validation "gitlab.com/mbugroup/lti-api.git/internal/modules/production/transfer_layings/validations"
@@ -19,31 +26,61 @@ import (
 type TransferLayingService interface {
 	GetAll(ctx *fiber.Ctx, params *validation.Query) ([]entity.LayingTransfer, int64, error)
 	GetOne(ctx *fiber.Ctx, id uint) (*entity.LayingTransfer, error)
+	GetOneWithApproval(ctx *fiber.Ctx, id uint) (*entity.LayingTransfer, *entity.Approval, error)
 	CreateOne(ctx *fiber.Ctx, req *validation.Create) (*entity.LayingTransfer, error)
 	UpdateOne(ctx *fiber.Ctx, req *validation.Update, id uint) (*entity.LayingTransfer, error)
 	DeleteOne(ctx *fiber.Ctx, id uint) error
+	Approval(ctx *fiber.Ctx, req *validation.Approve) ([]entity.LayingTransfer, error)
 }
 
 type transferLayingService struct {
-	Log                     *logrus.Logger
-	Validate                *validator.Validate
-	Repository              repository.TransferLayingRepository
-	ProjectFlockRepo        ProjectFlockRepository.ProjectflockRepository
-	ProjectFlockKandangRepo ProjectFlockRepository.ProjectFlockKandangRepository
+	Log                        *logrus.Logger
+	Validate                   *validator.Validate
+	Repository                 repository.TransferLayingRepository
+	ProjectFlockRepo           ProjectFlockRepository.ProjectflockRepository
+	ProjectFlockKandangRepo    ProjectFlockRepository.ProjectFlockKandangRepository
+	ProjectFlockPopulationRepo ProjectFlockRepository.ProjectFlockPopulationRepository
+	ProductWarehouseRepo       rInventory.ProductWarehouseRepository
+	WarehouseRepo              rWarehouse.WarehouseRepository
+	ApprovalService            commonSvc.ApprovalService
 }
 
-func NewTransferLayingService(repo repository.TransferLayingRepository, projectFlockRepo ProjectFlockRepository.ProjectflockRepository, projectFlockKandangRepo ProjectFlockRepository.ProjectFlockKandangRepository, validate *validator.Validate) TransferLayingService {
+func NewTransferLayingService(
+	repo repository.TransferLayingRepository,
+	projectFlockRepo ProjectFlockRepository.ProjectflockRepository,
+	projectFlockKandangRepo ProjectFlockRepository.ProjectFlockKandangRepository,
+	projectFlockPopulationRepo ProjectFlockRepository.ProjectFlockPopulationRepository,
+	productWarehouseRepo rInventory.ProductWarehouseRepository,
+	warehouseRepo rWarehouse.WarehouseRepository,
+	approvalService commonSvc.ApprovalService,
+	validate *validator.Validate,
+) TransferLayingService {
 	return &transferLayingService{
-		Log:                     utils.Log,
-		Validate:                validate,
-		Repository:              repo,
-		ProjectFlockRepo:        projectFlockRepo,
-		ProjectFlockKandangRepo: projectFlockKandangRepo,
+		Log:                        utils.Log,
+		Validate:                   validate,
+		Repository:                 repo,
+		ProjectFlockRepo:           projectFlockRepo,
+		ProjectFlockKandangRepo:    projectFlockKandangRepo,
+		ProjectFlockPopulationRepo: projectFlockPopulationRepo,
+		ProductWarehouseRepo:       productWarehouseRepo,
+		WarehouseRepo:              warehouseRepo,
+		ApprovalService:            approvalService,
 	}
 }
 
 func (s transferLayingService) withRelations(db *gorm.DB) *gorm.DB {
-	return db.Preload("CreatedUser")
+	return db.
+		Preload("CreatedUser").
+		Preload("Sources").
+		Preload("Sources.SourceProjectFlockKandang").
+		Preload("Sources.ProductWarehouse").
+		Preload("Sources.ProductWarehouse.Product").
+		Preload("Sources.ProductWarehouse.Warehouse").
+		Preload("Targets").
+		Preload("Targets.TargetProjectFlockKandang").
+		Preload("Targets.ProductWarehouse").
+		Preload("Targets.ProductWarehouse.Product").
+		Preload("Targets.ProductWarehouse.Warehouse")
 }
 
 func (s transferLayingService) GetAll(c *fiber.Ctx, params *validation.Query) ([]entity.LayingTransfer, int64, error) {
@@ -67,13 +104,45 @@ func (s transferLayingService) GetAll(c *fiber.Ctx, params *validation.Query) ([
 		if params.TransferDateTo != "" {
 			db = db.Where("transfer_date <= ?", params.TransferDateTo)
 		}
-		return db.Order("created_at DESC").Order("updated_at DESC")
+		if params.TransferNumber != "" {
+			db = db.Where("transfer_number ILIKE ?", "%"+params.TransferNumber+"%")
+		}
+
+		// Handle sort
+		sortField := "created_at"
+		if params.Sort != "" {
+			sortField = params.Sort
+		}
+		sortOrder := "DESC"
+		if params.Order == "asc" {
+			sortOrder = "ASC"
+		}
+		db = db.Order(fmt.Sprintf("%s %s", sortField, sortOrder))
+
+		return db
 	})
 
 	if err != nil {
 		s.Log.Errorf("Failed to get transferLayings: %+v", err)
 		return nil, 0, err
 	}
+
+	// Filter by approval status if requested
+	if params.ApprovalStatus != "" {
+		var filtered []entity.LayingTransfer
+		approvalRepo := commonRepo.NewApprovalRepository(s.Repository.DB())
+
+		for _, transfer := range transferLayings {
+			latestApproval, err := approvalRepo.LatestByTarget(c.Context(), string(utils.ApprovalWorkflowTransferToLaying), transfer.Id, nil)
+			if err == nil && latestApproval != nil && latestApproval.Action != nil {
+				if string(*latestApproval.Action) == params.ApprovalStatus {
+					filtered = append(filtered, transfer)
+				}
+			}
+		}
+		transferLayings = filtered
+	}
+
 	return transferLayings, total, nil
 }
 
@@ -86,37 +155,69 @@ func (s transferLayingService) GetOne(c *fiber.Ctx, id uint) (*entity.LayingTran
 		s.Log.Errorf("Failed get transferLaying by id: %+v", err)
 		return nil, err
 	}
+
+	// Fetch and populate latest approval
+	approvalRepo := commonRepo.NewApprovalRepository(s.Repository.DB())
+	latestApproval, err := approvalRepo.LatestByTarget(c.Context(), string(utils.ApprovalWorkflowTransferToLaying), transferLaying.Id, nil)
+	if err == nil && latestApproval != nil {
+		transferLaying.LatestApproval = latestApproval
+	}
+
 	return transferLaying, nil
 }
 
+func (s transferLayingService) GetOneWithApproval(c *fiber.Ctx, id uint) (*entity.LayingTransfer, *entity.Approval, error) {
+	transferLaying, err := s.GetOne(c, id)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// Return the LatestApproval that was populated in GetOne
+	return transferLaying, transferLaying.LatestApproval, nil
+}
+
 func (s *transferLayingService) CreateOne(c *fiber.Ctx, req *validation.Create) (*entity.LayingTransfer, error) {
 	if err := s.Validate.Struct(req); err != nil {
 		return nil, err
 	}
 
-	if err := common.EnsureRelations(c.Context(),
-		common.RelationCheck{Name: "Source Project Flock", ID: &req.SourceProjectFlockId, Exists: s.ProjectFlockRepo.IdExists},
-		common.RelationCheck{Name: "Target Project Flock", ID: &req.TargetProjectFlockId, Exists: s.ProjectFlockRepo.IdExists},
+	if err := commonSvc.EnsureRelations(c.Context(),
+		commonSvc.RelationCheck{Name: "Source Project Flock", ID: &req.SourceProjectFlockId, Exists: s.ProjectFlockRepo.IdExists},
+		commonSvc.RelationCheck{Name: "Target Project Flock", ID: &req.TargetProjectFlockId, Exists: s.ProjectFlockRepo.IdExists},
 	); err != nil {
 		return nil, err
 	}
 
-	// Validate source kandangs
 	for _, detail := range req.SourceKandangs {
-		if err := common.EnsureRelations(c.Context(),
-			common.RelationCheck{Name: "Source Project Flock Kandang", ID: &detail.ProjectFlockKandangId, Exists: s.ProjectFlockKandangRepo.IdExists},
+		if err := commonSvc.EnsureRelations(c.Context(),
+			commonSvc.RelationCheck{Name: "Source Project Flock Kandang", ID: &detail.ProjectFlockKandangId, Exists: s.ProjectFlockKandangRepo.IdExists},
 		); err != nil {
 			return nil, err
 		}
+
+		pfk, err := s.ProjectFlockKandangRepo.GetByID(c.Context(), detail.ProjectFlockKandangId)
+		if err != nil {
+			return nil, fiber.NewError(fiber.StatusInternalServerError, "Failed to get source project flock kandang")
+		}
+		if pfk.ProjectFlockId != req.SourceProjectFlockId {
+			return nil, fiber.NewError(fiber.StatusBadRequest, fmt.Sprintf("Source kandang %d does not belong to source project flock %d", detail.ProjectFlockKandangId, req.SourceProjectFlockId))
+		}
 	}
 
-	// Validate target kandangs
 	for _, detail := range req.TargetKandangs {
-		if err := common.EnsureRelations(c.Context(),
-			common.RelationCheck{Name: "Target Project Flock Kandang", ID: &detail.ProjectFlockKandangId, Exists: s.ProjectFlockKandangRepo.IdExists},
+		if err := commonSvc.EnsureRelations(c.Context(),
+			commonSvc.RelationCheck{Name: "Target Project Flock Kandang", ID: &detail.ProjectFlockKandangId, Exists: s.ProjectFlockKandangRepo.IdExists},
 		); err != nil {
 			return nil, err
 		}
+
+		pfk, err := s.ProjectFlockKandangRepo.GetByID(c.Context(), detail.ProjectFlockKandangId)
+		if err != nil {
+			return nil, fiber.NewError(fiber.StatusInternalServerError, "Failed to get target project flock kandang")
+		}
+		if pfk.ProjectFlockId != req.TargetProjectFlockId {
+			return nil, fiber.NewError(fiber.StatusBadRequest, fmt.Sprintf("Target kandang %d does not belong to target project flock %d", detail.ProjectFlockKandangId, req.TargetProjectFlockId))
+		}
 	}
 
 	transferDate, err := utils.ParseDateString(req.TransferDate)
@@ -124,34 +225,133 @@ func (s *transferLayingService) CreateOne(c *fiber.Ctx, req *validation.Create)
 		return nil, fiber.NewError(fiber.StatusBadRequest, "Invalid transfer date format")
 	}
 
-	var totalQty float64
-	for _, item := range req.SourceKandangs {
-		totalQty += item.Quantity
+	var totalSourceQty, totalTargetQty float64
+	sourceWarehouseMap := make(map[uint]uint)
+
+	for _, sourceDetail := range req.SourceKandangs {
+		if sourceDetail.Quantity <= 0 {
+			return nil, fiber.NewError(fiber.StatusBadRequest, "Source kandang quantity must be greater than 0")
+		}
+		totalSourceQty += sourceDetail.Quantity
+
+		populations, err := s.ProjectFlockPopulationRepo.GetByProjectFlockKandangID(c.Context(), sourceDetail.ProjectFlockKandangId)
+		if err != nil {
+			return nil, err
+		}
+
+		var totalPopulation float64
+		var productWarehouseId uint
+		for _, pop := range populations {
+			totalPopulation += pop.TotalQty
+			if productWarehouseId == 0 {
+				productWarehouseId = pop.ProductWarehouseId
+			}
+		}
+
+		if totalPopulation == 0 {
+			return nil, fiber.NewError(fiber.StatusBadRequest, fmt.Sprintf("Source kandang %d has no population available for transfer", sourceDetail.ProjectFlockKandangId))
+		}
+
+		if totalPopulation < sourceDetail.Quantity {
+			return nil, fiber.NewError(fiber.StatusBadRequest, fmt.Sprintf("Source kandang %d has insufficient quantity. Available: %.0f, Requested: %.0f", sourceDetail.ProjectFlockKandangId, totalPopulation, sourceDetail.Quantity))
+		}
+
+		sourceWarehouseMap[sourceDetail.ProjectFlockKandangId] = productWarehouseId
+	}
+
+	for _, targetDetail := range req.TargetKandangs {
+		if targetDetail.Quantity <= 0 {
+			return nil, fiber.NewError(fiber.StatusBadRequest, "Target kandang quantity must be greater than 0")
+		}
+		totalTargetQty += targetDetail.Quantity
+	}
+
+	if totalSourceQty != totalTargetQty {
+		return nil, fiber.NewError(fiber.StatusBadRequest, fmt.Sprintf("Total source quantity (%f) must equal total target quantity (%f)", totalSourceQty, totalTargetQty))
+	}
+
+	transferNumber := fmt.Sprintf("TL-%d", time.Now().UnixNano())
+
+	createBody := &entity.LayingTransfer{
+		TransferNumber:     transferNumber,
+		Notes:              req.Reason,
+		FromProjectFlockId: req.SourceProjectFlockId,
+		ToProjectFlockId:   req.TargetProjectFlockId,
+		TransferDate:       transferDate,
+		PendingUsageQty:    &totalSourceQty,
+		CreatedBy:          1, //todo : harus diambil dari auth
 	}
 
 	err = s.Repository.DB().WithContext(c.Context()).Transaction(func(dbTransaction *gorm.DB) error {
 
-		createBody := &entity.LayingTransfer{
-			Notes:              req.Reason,
-			FromProjectFlockId: req.SourceProjectFlockId,
-			ToProjectFlockId:   req.TargetProjectFlockId,
-			TransferDate:       transferDate,
-			TotalQty:           totalQty,
-			CreatedBy:          1, //todo : harus diambil dari auth
+		if err := s.Repository.WithTx(dbTransaction).CreateOne(c.Context(), createBody, nil); err != nil {
+			return fiber.NewError(fiber.StatusInternalServerError, "Failed to create transfer laying record")
 		}
 
-		if err := s.Repository.WithTx(dbTransaction).CreateOne(c.Context(), createBody, nil); err != nil {
-			return err
+		productWarehouseRepoTx := s.ProductWarehouseRepo.WithTxRepo(dbTransaction)
+		projectFlockPopulationRepoTx := s.ProjectFlockPopulationRepo.WithTx(dbTransaction)
+
+		for _, sourceDetail := range req.SourceKandangs {
+			productWarehouseId := sourceWarehouseMap[sourceDetail.ProjectFlockKandangId]
+
+			source := entity.LayingTransferSource{
+				LayingTransferId:            createBody.Id,
+				SourceProjectFlockKandangId: sourceDetail.ProjectFlockKandangId,
+				Qty:                         sourceDetail.Quantity,
+				ProductWarehouseId:          &productWarehouseId,
+			}
+			if err := dbTransaction.Create(&source).Error; err != nil {
+				return fiber.NewError(fiber.StatusInternalServerError, "Failed to create transfer source")
+			}
+
+			if err := s.reduceProjectFlockPopulation(c.Context(), projectFlockPopulationRepoTx, sourceDetail.ProjectFlockKandangId, sourceDetail.Quantity); err != nil {
+				return fiber.NewError(fiber.StatusInternalServerError, "Failed to reduce project flock population")
+			}
+
+			if err := productWarehouseRepoTx.PatchOne(c.Context(), productWarehouseId, map[string]any{"quantity": gorm.Expr("quantity - ?", sourceDetail.Quantity)}, nil); err != nil {
+				return fiber.NewError(fiber.StatusInternalServerError, "Failed to update source warehouse quantity")
+			}
+		}
+
+		for _, targetDetail := range req.TargetKandangs {
+
+			targetPFK, err := s.ProjectFlockKandangRepo.GetByID(c.Context(), targetDetail.ProjectFlockKandangId)
+			if err != nil {
+				return fiber.NewError(fiber.StatusInternalServerError, "Failed to get target project flock kandang")
+			}
+
+			// Get warehouse for this kandang
+			targetWarehouse, err := s.WarehouseRepo.GetLatestByKandangID(c.Context(), targetPFK.KandangId)
+			if err != nil {
+				if errors.Is(err, gorm.ErrRecordNotFound) {
+					return fiber.NewError(fiber.StatusBadRequest, fmt.Sprintf("No warehouse found for target kandang %d", targetDetail.ProjectFlockKandangId))
+				}
+				return fiber.NewError(fiber.StatusInternalServerError, "Failed to get target warehouse")
+			}
+
+			target := entity.LayingTransferTarget{
+				LayingTransferId:            createBody.Id,
+				TargetProjectFlockKandangId: targetDetail.ProjectFlockKandangId,
+				Qty:                         targetDetail.Quantity,
+				ProductWarehouseId:          &targetWarehouse.Id,
+			}
+			if err := dbTransaction.Create(&target).Error; err != nil {
+				return fiber.NewError(fiber.StatusInternalServerError, "Failed to create transfer target")
+			}
+		}
+
+		if err := createApprovalTransferLaying(c.Context(), dbTransaction, createBody.Id, createBody.CreatedBy); err != nil {
+			return fiber.NewError(fiber.StatusInternalServerError, "Failed to create transfer approval")
 		}
 
 		return nil
 	})
 
 	if err != nil {
-		return nil, err
+		return nil, fiber.NewError(fiber.StatusInternalServerError, "Failed to create transfer laying")
 	}
 
-	return nil, err
+	return s.GetOne(c, createBody.Id)
 }
 
 func (s transferLayingService) UpdateOne(c *fiber.Ctx, req *validation.Update, id uint) (*entity.LayingTransfer, error) {
@@ -159,6 +359,30 @@ func (s transferLayingService) UpdateOne(c *fiber.Ctx, req *validation.Update, i
 		return nil, err
 	}
 
+	// Check if transfer laying exists
+	_, err := s.Repository.GetByID(c.Context(), id, nil)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, fiber.NewError(fiber.StatusNotFound, "TransferLaying not found")
+		}
+		return nil, fiber.NewError(fiber.StatusInternalServerError, "Failed to get transfer laying")
+	}
+
+	// Check if latest approval is PENDING (not approved)
+	approvalRepo := commonRepo.NewApprovalRepository(s.Repository.DB())
+	latestApproval, err := approvalRepo.LatestByTarget(c.Context(), string(utils.ApprovalWorkflowTransferToLaying), id, nil)
+	if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
+		return nil, fiber.NewError(fiber.StatusInternalServerError, "Failed to check approval status")
+	}
+
+	// If latest approval exists and is APPROVED or REJECTED, cannot update
+	if latestApproval != nil && latestApproval.Action != nil {
+		action := string(*latestApproval.Action)
+		if action == string(entity.ApprovalActionApproved) || action == string(entity.ApprovalActionRejected) {
+			return nil, fiber.NewError(fiber.StatusBadRequest, fmt.Sprintf("Cannot update transfer laying with status %s", action))
+		}
+	}
+
 	updateBody := make(map[string]any)
 
 	if req.TransferDate != nil {
@@ -178,19 +402,333 @@ func (s transferLayingService) UpdateOne(c *fiber.Ctx, req *validation.Update, i
 			return nil, fiber.NewError(fiber.StatusNotFound, "TransferLaying not found")
 		}
 		s.Log.Errorf("Failed to update transferLaying: %+v", err)
-		return nil, err
+		return nil, fiber.NewError(fiber.StatusInternalServerError, "Failed to update transfer laying")
 	}
 
 	return s.GetOne(c, id)
 }
 
 func (s transferLayingService) DeleteOne(c *fiber.Ctx, id uint) error {
-	if err := s.Repository.DeleteOne(c.Context(), id); err != nil {
+	// Verify transfer laying exists
+	_, err := s.Repository.GetByID(c.Context(), id, func(db *gorm.DB) *gorm.DB {
+		return db.Preload("Sources.ProductWarehouse").Preload("Targets")
+	})
+	if err != nil {
 		if errors.Is(err, gorm.ErrRecordNotFound) {
 			return fiber.NewError(fiber.StatusNotFound, "TransferLaying not found")
 		}
-		s.Log.Errorf("Failed to delete transferLaying: %+v", err)
-		return err
+		return fiber.NewError(fiber.StatusInternalServerError, "Failed to get transfer laying")
 	}
+
+	// Check if latest approval is PENDING (not approved/rejected)
+	approvalRepo := commonRepo.NewApprovalRepository(s.Repository.DB())
+	latestApproval, err := approvalRepo.LatestByTarget(c.Context(), string(utils.ApprovalWorkflowTransferToLaying), id, nil)
+	if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
+		return fiber.NewError(fiber.StatusInternalServerError, "Failed to check approval status")
+	}
+
+	// If latest approval exists and is APPROVED or REJECTED, cannot delete
+	if latestApproval != nil && latestApproval.Action != nil {
+		action := string(*latestApproval.Action)
+		if action == string(entity.ApprovalActionApproved) || action == string(entity.ApprovalActionRejected) {
+			return fiber.NewError(fiber.StatusBadRequest, fmt.Sprintf("Cannot delete transfer laying with status %s", action))
+		}
+	}
+
+	// Delete in transaction to handle cascades and qty restoration
+	err = s.Repository.DB().WithContext(c.Context()).Transaction(func(dbTransaction *gorm.DB) error {
+		// Restore source warehouse quantities
+		productWarehouseRepoTx := s.ProductWarehouseRepo.WithTxRepo(dbTransaction)
+
+		// Get source repository for detail info
+		sourceRepoTx := repository.NewLayingTransferSourceRepository(dbTransaction)
+		sources, err := sourceRepoTx.GetByLayingTransferId(c.Context(), id)
+		if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
+			return fiber.NewError(fiber.StatusInternalServerError, "Failed to get transfer sources")
+		}
+
+		// Restore quantity for each source that was reduced
+		for _, source := range sources {
+			if source.ProductWarehouseId != nil && source.Qty > 0 {
+				// Add back the quantity that was transferred
+				if err := productWarehouseRepoTx.PatchOne(c.Context(), *source.ProductWarehouseId, map[string]any{
+					"quantity": gorm.Expr("quantity + ?", source.Qty),
+				}, nil); err != nil {
+					return fiber.NewError(fiber.StatusInternalServerError, "Failed to restore source warehouse quantity")
+				}
+			}
+		}
+
+		// Restore project flock population that was reduced
+		projectFlockPopulationRepoTx := s.ProjectFlockPopulationRepo.WithTx(dbTransaction)
+		for _, source := range sources {
+			populations, err := projectFlockPopulationRepoTx.GetByProjectFlockKandangID(c.Context(), source.SourceProjectFlockKandangId)
+			if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
+				return fiber.NewError(fiber.StatusInternalServerError, "Failed to get populations for restoration")
+			}
+
+			// Restore to latest populations first
+			remainingToRestore := source.Qty
+			for i := len(populations) - 1; i >= 0 && remainingToRestore > 0; i-- {
+				pop := populations[i]
+				restoreAmount := remainingToRestore
+				if remainingToRestore < pop.TotalQty {
+					// Cap restore to what can fit in this population
+					restoreAmount = remainingToRestore
+				}
+
+				newQty := pop.TotalQty + restoreAmount
+				if err := projectFlockPopulationRepoTx.PatchOne(c.Context(), pop.Id, map[string]any{"total_qty": newQty}, nil); err != nil {
+					return fiber.NewError(fiber.StatusInternalServerError, "Failed to restore population quantity")
+				}
+
+				remainingToRestore -= restoreAmount
+			}
+		}
+
+		// Delete the transfer laying (cascade will delete sources and targets)
+		if err := s.Repository.WithTx(dbTransaction).DeleteOne(c.Context(), id); err != nil {
+			return fiber.NewError(fiber.StatusInternalServerError, "Failed to delete transfer laying")
+		}
+
+		return nil
+	})
+
+	if err != nil {
+		if fiberErr, ok := err.(*fiber.Error); ok {
+			return fiberErr
+		}
+		s.Log.Errorf("Failed to delete transferLaying: %+v", err)
+		return fiber.NewError(fiber.StatusInternalServerError, "Failed to delete transfer laying")
+	}
+
+	return nil
+}
+
+func (s transferLayingService) Approval(c *fiber.Ctx, req *validation.Approve) ([]entity.LayingTransfer, error) {
+	if err := s.Validate.Struct(req); err != nil {
+		return nil, err
+	}
+
+	actorID := uint(1) // TODO: change from auth context
+	var action entity.ApprovalAction
+	switch strings.ToUpper(strings.TrimSpace(req.Action)) {
+	case string(entity.ApprovalActionRejected):
+		action = entity.ApprovalActionRejected
+	case string(entity.ApprovalActionApproved):
+		action = entity.ApprovalActionApproved
+	default:
+		return nil, fiber.NewError(fiber.StatusBadRequest, "action must be APPROVED or REJECTED")
+	}
+
+	approvableIDs := utils.UniqueUintSlice(req.ApprovableIds)
+	if len(approvableIDs) == 0 {
+		return nil, fiber.NewError(fiber.StatusBadRequest, "approvable_ids must contain at least one id")
+	}
+
+	step := utils.TransferToLayingStepPengajuan
+	if action == entity.ApprovalActionApproved {
+		step = utils.TransferToLayingStepDisetujui
+	}
+
+	err := s.Repository.DB().WithContext(c.Context()).Transaction(func(dbTransaction *gorm.DB) error {
+
+		approvalSvcTx := commonSvc.NewApprovalService(commonRepo.NewApprovalRepository(dbTransaction))
+		sourceRepoTx := repository.NewLayingTransferSourceRepository(dbTransaction)
+		targetRepoTx := repository.NewLayingTransferTargetRepository(dbTransaction)
+		productWarehouseRepoTx := s.ProductWarehouseRepo.WithTxRepo(dbTransaction)
+
+		for _, approvableID := range approvableIDs {
+			transfer, err := s.Repository.GetByID(c.Context(), approvableID, nil)
+			if err != nil {
+				if errors.Is(err, gorm.ErrRecordNotFound) {
+					return fiber.NewError(fiber.StatusNotFound, fmt.Sprintf("TransferLaying %d not found", approvableID))
+				}
+				return err
+			}
+
+			if _, err := approvalSvcTx.CreateApproval(
+				c.Context(),
+				utils.ApprovalWorkflowTransferToLaying,
+				approvableID,
+				step,
+				&action,
+				actorID,
+				req.Notes,
+			); err != nil {
+				return fiber.NewError(fiber.StatusInternalServerError, "Failed to record approval")
+			}
+
+			if action == entity.ApprovalActionApproved && transfer.PendingUsageQty != nil && *transfer.PendingUsageQty > 0 {
+
+				sources, err := sourceRepoTx.GetByLayingTransferId(c.Context(), approvableID)
+				if err != nil {
+					return fiber.NewError(fiber.StatusInternalServerError, "Failed to get transfer sources")
+				}
+
+				targets, err := targetRepoTx.GetByLayingTransferId(c.Context(), approvableID)
+				if err != nil {
+					return fiber.NewError(fiber.StatusInternalServerError, "Failed to get transfer targets")
+				}
+
+				if len(sources) > 0 && len(targets) > 0 {
+					firstSource := sources[0]
+					if firstSource.ProductWarehouseId == nil {
+						return fiber.NewError(fiber.StatusInternalServerError, fmt.Sprintf("Source product warehouse not found for transfer %d", approvableID))
+					}
+
+					sourceWarehouse, err := productWarehouseRepoTx.GetByID(c.Context(), *firstSource.ProductWarehouseId, nil)
+					if err != nil {
+						return fiber.NewError(fiber.StatusInternalServerError, "Failed to get source warehouse")
+					}
+
+					for _, target := range targets {
+
+						targetPFK, err := s.ProjectFlockKandangRepo.GetByID(c.Context(), target.TargetProjectFlockKandangId)
+						if err != nil {
+							if errors.Is(err, gorm.ErrRecordNotFound) {
+								continue
+							}
+							return fiber.NewError(fiber.StatusInternalServerError, "Failed to get target project flock kandang")
+						}
+
+						targetWarehouse, err := s.WarehouseRepo.GetLatestByKandangID(c.Context(), targetPFK.KandangId)
+						if err != nil {
+							if errors.Is(err, gorm.ErrRecordNotFound) {
+								continue
+							}
+							return fiber.NewError(fiber.StatusInternalServerError, "Failed to get target warehouse")
+						}
+
+						if _, err := s.getOrCreateProductWarehouse(
+							c.Context(),
+							dbTransaction,
+							sourceWarehouse.ProductId,
+							targetWarehouse.Id,
+							target.Qty,
+						); err != nil {
+							return fiber.NewError(fiber.StatusInternalServerError, "Failed to create or update product warehouse")
+						}
+					}
+				}
+
+				usageQty := *transfer.PendingUsageQty
+				updateData := map[string]any{
+					"usage_qty":         usageQty,
+					"pending_usage_qty": nil,
+				}
+				if err := s.Repository.WithTx(dbTransaction).PatchOne(c.Context(), approvableID, updateData, nil); err != nil {
+					return fiber.NewError(fiber.StatusInternalServerError, "Failed to update transfer laying status")
+				}
+			}
+		}
+
+		return nil
+	})
+
+	if err != nil {
+		if fiberErr, ok := err.(*fiber.Error); ok {
+			return nil, fiberErr
+		}
+		return nil, fiber.NewError(fiber.StatusInternalServerError, "Failed to record approval")
+	}
+
+	updated := make([]entity.LayingTransfer, 0, len(approvableIDs))
+	for _, approvableID := range approvableIDs {
+		transfer, err := s.GetOne(c, approvableID)
+		if err != nil {
+			return nil, err
+		}
+		updated = append(updated, *transfer)
+	}
+
+	return updated, nil
+}
+
+func createApprovalTransferLaying(ctx context.Context, tx *gorm.DB, transferLayingID uint, actorID uint) error {
+	if transferLayingID == 0 || actorID == 0 {
+		return nil
+	}
+
+	approvalSvc := commonSvc.NewApprovalService(commonRepo.NewApprovalRepository(tx))
+	action := entity.ApprovalActionCreated
+
+	_, err := approvalSvc.CreateApproval(
+		ctx,
+		utils.ApprovalWorkflowTransferToLaying,
+		transferLayingID,
+		utils.TransferToLayingStepPengajuan,
+		&action,
+		actorID,
+		nil,
+	)
+	return err
+}
+
+func (s *transferLayingService) getOrCreateProductWarehouse(ctx context.Context, tx *gorm.DB, productID uint, warehouseID uint, quantity float64) (*entity.ProductWarehouse, error) {
+
+	productWarehouseRepoTx := s.ProductWarehouseRepo.WithTxRepo(tx)
+
+	existing, err := productWarehouseRepoTx.GetProductWarehouseByProductAndWarehouseID(ctx, productID, warehouseID)
+	if err == nil && existing != nil {
+
+		if err := productWarehouseRepoTx.PatchOne(ctx, existing.Id, map[string]any{"quantity": gorm.Expr("quantity + ?", quantity)}, nil); err != nil {
+			return nil, err
+		}
+		return existing, nil
+	}
+	if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
+		return nil, err
+	}
+
+	newWarehouse := &entity.ProductWarehouse{
+		ProductId:   productID,
+		WarehouseId: warehouseID,
+		Quantity:    quantity,
+	}
+
+	if err := productWarehouseRepoTx.CreateOne(ctx, newWarehouse, nil); err != nil {
+		return nil, err
+	}
+
+	return newWarehouse, nil
+}
+
+func (s *transferLayingService) reduceProjectFlockPopulation(ctx context.Context, populationRepo ProjectFlockRepository.ProjectFlockPopulationRepository, projectFlockKandangID uint, quantityToReduce float64) error {
+
+	populations, err := populationRepo.GetByProjectFlockKandangID(ctx, projectFlockKandangID)
+	if err != nil {
+		return err
+	}
+
+	if len(populations) == 0 {
+		return fiber.NewError(fiber.StatusBadRequest, "No populations found for reduction")
+	}
+
+	remainingToReduce := quantityToReduce
+
+	for i := len(populations) - 1; i >= 0; i-- {
+		if remainingToReduce <= 0 {
+			break
+		}
+
+		pop := populations[i]
+		reductionAmount := remainingToReduce
+		if pop.TotalQty < remainingToReduce {
+			reductionAmount = pop.TotalQty
+		}
+
+		newQty := pop.TotalQty - reductionAmount
+		if err := populationRepo.PatchOne(ctx, pop.Id, map[string]any{"total_qty": newQty}, nil); err != nil {
+			return err
+		}
+
+		remainingToReduce -= reductionAmount
+	}
+
+	if remainingToReduce > 0 {
+		return fiber.NewError(fiber.StatusBadRequest, fmt.Sprintf("Insufficient population to reduce. Still need to reduce: %.0f", remainingToReduce))
+	}
+
 	return nil
 }