from rest_framework import viewsets, status from rest_framework.decorators import action from rest_framework.response import Response from rest_framework.permissions import IsAuthenticated from django.db.models import Q, Count, Sum, F, Avg from django.utils import timezone from datetime import timedelta from .models import Transfer, TransferItem, TransferComment, TransferEvent from .serializers import ( TransferListSerializer, TransferDetailSerializer, CreateTransferSerializer, UpdateTransferSerializer, ApproveTransferSerializer, RejectTransferSerializer, ShipTransferSerializer, ReceiveTransferSerializer, AddCommentSerializer, CancelTransferSerializer, TransferCommentSerializer ) from .permissions import TransferPermission class TransferViewSet(viewsets.ModelViewSet): """ViewSet for managing transfers""" permission_classes = [IsAuthenticated, TransferPermission] def get_queryset(self): """Optimize queryset with related data""" queryset = Transfer.objects.select_related( 'business', 'source_location', 'destination_location', 'requested_by', 'approved_by', 'received_by', 'rejected_by' ).prefetch_related( 'items__inventory_item__brand', 'items__inventory_item__category', 'comments__user', 'events__user' ) # Filter by business business_id = self.request.query_params.get('business_id') if business_id: queryset = queryset.filter(business_id=business_id) # Filter by status status_filter = self.request.query_params.get('status') if status_filter: queryset = queryset.filter(status=status_filter) # Filter by source location source_location = self.request.query_params.get('source_location') if source_location: queryset = queryset.filter(source_location_id=source_location) # Filter by destination location destination_location = self.request.query_params.get('destination_location') if destination_location: queryset = queryset.filter(destination_location_id=destination_location) # Filter by date range start_date = self.request.query_params.get('start_date') end_date = self.request.query_params.get('end_date') if start_date and end_date: queryset = queryset.filter( created_at__date__gte=start_date, created_at__date__lte=end_date ) # Search by transfer number search = self.request.query_params.get('search') if search: queryset = queryset.filter( Q(transfer_number__icontains=search) | Q(notes__icontains=search) ) # Check user's location access user = self.request.user membership = user.business_memberships.filter( business_id=business_id, status='ACTIVE' ).first() if membership and not membership.can_access_all_locations: if membership.role.name not in ['OWNER', 'ADMIN']: accessible_locations = membership.accessible_locations.values_list('id', flat=True) queryset = queryset.filter( Q(source_location_id__in=accessible_locations) | Q(destination_location_id__in=accessible_locations) ) return queryset def get_serializer_class(self): """Return appropriate serializer based on action""" if self.action == 'list': return TransferListSerializer elif self.action == 'create': return CreateTransferSerializer elif self.action in ['update', 'partial_update']: return UpdateTransferSerializer return TransferDetailSerializer def create(self, request, *args, **kwargs): """Create a new transfer""" serializer = self.get_serializer(data=request.data) serializer.is_valid(raise_exception=True) transfer = serializer.save() # Return detailed response detail_serializer = TransferDetailSerializer(transfer) return Response( detail_serializer.data, status=status.HTTP_201_CREATED ) def update(self, request, *args, **kwargs): """Update transfer (only allowed for PENDING transfers)""" transfer = self.get_object() if transfer.status != 'PENDING': return Response( {'error': 'Only pending transfers can be updated'}, status=status.HTTP_400_BAD_REQUEST ) serializer = self.get_serializer(transfer, data=request.data, partial=True) serializer.is_valid(raise_exception=True) # Update fields for field, value in serializer.validated_data.items(): setattr(transfer, field, value) transfer.save() detail_serializer = TransferDetailSerializer(transfer) return Response(detail_serializer.data) def destroy(self, request, *args, **kwargs): """Delete transfer (only allowed for PENDING transfers)""" transfer = self.get_object() if transfer.status != 'PENDING': return Response( {'error': 'Only pending transfers can be deleted'}, status=status.HTTP_400_BAD_REQUEST ) transfer.delete() return Response(status=status.HTTP_204_NO_CONTENT) @action(detail=True, methods=['post']) def approve(self, request, pk=None): """Approve a transfer""" transfer = self.get_object() serializer = ApproveTransferSerializer(data=request.data) serializer.is_valid(raise_exception=True) try: transfer.approve( user=request.user, notes=serializer.validated_data.get('notes') ) detail_serializer = TransferDetailSerializer(transfer) return Response(detail_serializer.data) except PermissionError as e: return Response( {'error': str(e)}, status=status.HTTP_403_FORBIDDEN ) except Exception as e: return Response( {'error': str(e)}, status=status.HTTP_400_BAD_REQUEST ) @action(detail=True, methods=['post']) def reject(self, request, pk=None): """Reject a transfer""" transfer = self.get_object() serializer = RejectTransferSerializer(data=request.data) serializer.is_valid(raise_exception=True) try: transfer.reject( user=request.user, reason=serializer.validated_data['reason'] ) detail_serializer = TransferDetailSerializer(transfer) return Response(detail_serializer.data) except PermissionError as e: return Response( {'error': str(e)}, status=status.HTTP_403_FORBIDDEN ) except Exception as e: return Response( {'error': str(e)}, status=status.HTTP_400_BAD_REQUEST ) @action(detail=True, methods=['post']) def ship(self, request, pk=None): """Mark transfer as shipped""" transfer = self.get_object() serializer = ShipTransferSerializer(data=request.data) serializer.is_valid(raise_exception=True) try: transfer.ship( user=request.user, carrier_name=serializer.validated_data.get('carrier_name'), tracking_number=serializer.validated_data.get('tracking_number') ) # Update additional shipping info if 'shipping_method' in serializer.validated_data: transfer.shipping_method = serializer.validated_data['shipping_method'] if 'estimated_cost' in serializer.validated_data: transfer.estimated_cost = serializer.validated_data['estimated_cost'] transfer.save() detail_serializer = TransferDetailSerializer(transfer) return Response(detail_serializer.data) except PermissionError as e: return Response( {'error': str(e)}, status=status.HTTP_403_FORBIDDEN ) except Exception as e: return Response( {'error': str(e)}, status=status.HTTP_400_BAD_REQUEST ) @action(detail=True, methods=['post']) def delivered(self, request, pk=None): """Mark transfer as delivered""" transfer = self.get_object() try: transfer.mark_delivered(user=request.user) detail_serializer = TransferDetailSerializer(transfer) return Response(detail_serializer.data) except ValueError as e: return Response( {'error': str(e)}, status=status.HTTP_400_BAD_REQUEST ) except Exception as e: return Response( {'error': str(e)}, status=status.HTTP_400_BAD_REQUEST ) @action(detail=True, methods=['post']) def receive(self, request, pk=None): """Receive transfer at destination""" transfer = self.get_object() serializer = ReceiveTransferSerializer(data=request.data) serializer.is_valid(raise_exception=True) try: transfer.receive( user=request.user, items_data=serializer.validated_data['items'], has_discrepancies=serializer.validated_data.get('has_discrepancies', False), discrepancy_report=serializer.validated_data.get('discrepancy_report') ) detail_serializer = TransferDetailSerializer(transfer) return Response(detail_serializer.data) except PermissionError as e: return Response( {'error': str(e)}, status=status.HTTP_403_FORBIDDEN ) except Exception as e: return Response( {'error': str(e)}, status=status.HTTP_400_BAD_REQUEST ) @action(detail=True, methods=['post']) def cancel(self, request, pk=None): """Cancel a transfer""" transfer = self.get_object() serializer = CancelTransferSerializer(data=request.data) serializer.is_valid(raise_exception=True) if transfer.status not in ['PENDING', 'APPROVED']: return Response( {'error': 'Only pending or approved transfers can be cancelled'}, status=status.HTTP_400_BAD_REQUEST ) transfer.status = 'CANCELLED' transfer.notes = f"{transfer.notes}\n\nCancellation reason: {serializer.validated_data['reason']}".strip() transfer.save() # Create event TransferEvent.objects.create( transfer=transfer, event_type='CANCELLED', user=request.user, notes=serializer.validated_data['reason'] ) detail_serializer = TransferDetailSerializer(transfer) return Response(detail_serializer.data) @action(detail=True, methods=['post']) def add_comment(self, request, pk=None): """Add a comment to transfer""" transfer = self.get_object() serializer = AddCommentSerializer(data=request.data) serializer.is_valid(raise_exception=True) comment = TransferComment.objects.create( transfer=transfer, user=request.user, text=serializer.validated_data['text'], is_internal=serializer.validated_data.get('is_internal', False) ) # Create event TransferEvent.objects.create( transfer=transfer, event_type='COMMENT_ADDED', user=request.user, notes=f"Comment added: {serializer.validated_data['text'][:50]}..." ) comment_serializer = TransferCommentSerializer(comment) return Response(comment_serializer.data, status=status.HTTP_201_CREATED) @action(detail=True, methods=['get']) def comments(self, request, pk=None): """Get all comments for a transfer""" transfer = self.get_object() comments = transfer.comments.all() serializer = TransferCommentSerializer(comments, many=True) return Response(serializer.data) @action(detail=True, methods=['get']) def events(self, request, pk=None): """Get event history for a transfer""" transfer = self.get_object() from .serializers import TransferEventSerializer events = transfer.events.all() serializer = TransferEventSerializer(events, many=True) return Response(serializer.data) @action(detail=False, methods=['get']) def stats(self, request): """Get transfer statistics""" business_id = request.query_params.get('business_id') if not business_id: return Response( {'error': 'business_id is required'}, status=status.HTTP_400_BAD_REQUEST ) # Get date range for comparison (last 30 days vs previous 30 days) today = timezone.now().date() current_period_start = today - timedelta(days=30) previous_period_start = today - timedelta(days=60) # Current period stats current_pending = Transfer.objects.filter( business_id=business_id, status='PENDING', created_at__date__gte=current_period_start ).count() current_in_transit = Transfer.objects.filter( business_id=business_id, status='IN_TRANSIT', created_at__date__gte=current_period_start ).count() current_completed = Transfer.objects.filter( business_id=business_id, status='RECEIVED', created_at__date__gte=current_period_start ).count() # Previous period stats for comparison previous_pending = Transfer.objects.filter( business_id=business_id, status='PENDING', created_at__date__gte=previous_period_start, created_at__date__lt=current_period_start ).count() previous_in_transit = Transfer.objects.filter( business_id=business_id, status='IN_TRANSIT', created_at__date__gte=previous_period_start, created_at__date__lt=current_period_start ).count() # Calculate percentage changes pending_change = self._calculate_change(previous_pending, current_pending) in_transit_change = self._calculate_change(previous_in_transit, current_in_transit) # Total value total_value = Transfer.objects.filter( business_id=business_id, created_at__date__gte=current_period_start ).aggregate( total=Sum(F('items__quantity') * F('items__inventory_item__selling_price')) )['total'] or 0 # Average transfer time avg_time = Transfer.objects.filter( business_id=business_id, status='RECEIVED', received_date__isnull=False, shipped_date__isnull=False ).aggregate( avg_days=Avg(F('received_date') - F('shipped_date')) )['avg_days'] avg_transfer_time = avg_time.days if avg_time else 0 return Response({ 'pending_count': current_pending, 'pending_change': pending_change, 'in_transit_count': current_in_transit, 'in_transit_change': in_transit_change, 'completed_count': current_completed, 'completed_period': 'Last 30 days', 'total_value': float(total_value), 'average_transfer_time': avg_transfer_time, }) @action(detail=False, methods=['get']) def pending(self, request): """Get pending transfers""" business_id = request.query_params.get('business_id') if not business_id: return Response( {'error': 'business_id is required'}, status=status.HTTP_400_BAD_REQUEST ) transfers = self.get_queryset().filter( business_id=business_id, status='PENDING' ) serializer = TransferListSerializer(transfers, many=True) return Response(serializer.data) @action(detail=False, methods=['get'], url_path='in-transit') def in_transit(self, request): """Get in-transit transfers""" business_id = request.query_params.get('business_id') if not business_id: return Response( {'error': 'business_id is required'}, status=status.HTTP_400_BAD_REQUEST ) transfers = self.get_queryset().filter( business_id=business_id, status='IN_TRANSIT' ) serializer = TransferListSerializer(transfers, many=True) return Response(serializer.data) @action(detail=False, methods=['get'], url_path='location-summary') def location_summary(self, request): """Get transfer summary by location""" business_id = request.query_params.get('business_id') if not business_id: return Response( {'error': 'business_id is required'}, status=status.HTTP_400_BAD_REQUEST ) from apps.business.models import Location locations = Location.objects.filter(business_id=business_id) summary = [] for location in locations: outgoing = Transfer.objects.filter( business_id=business_id, source_location=location ) incoming = Transfer.objects.filter( business_id=business_id, destination_location=location ) outgoing_value = outgoing.aggregate( total=Sum(F('items__quantity') * F('items__inventory_item__selling_price')) )['total'] or 0 incoming_value = incoming.aggregate( total=Sum(F('items__quantity') * F('items__inventory_item__selling_price')) )['total'] or 0 summary.append({ 'location_id': str(location.id), 'location_name': location.name, 'outgoing_count': outgoing.count(), 'incoming_count': incoming.count(), 'outgoing_value': float(outgoing_value), 'incoming_value': float(incoming_value), }) return Response({'locations': summary}) def _calculate_change(self, previous, current): """Calculate percentage change""" if previous == 0: return 100 if current > 0 else 0 return round(((current - previous) / previous) * 100, 2)