# backend/modules/task_management/views.py

import logging
from rest_framework import viewsets, permissions
from rest_framework.exceptions import ValidationError
from .models import Task
from .serializers import TaskSerializer
from .services import TaskService

# Postavljanje loggera za modul
logger = logging.getLogger(__name__)

class TaskViewSet(viewsets.ModelViewSet):
    """
    ViewSet koji koristi TaskService za rukovanje operacijama.
    """
    serializer_class = TaskSerializer
    permission_classes = [permissions.IsAuthenticated]

    def get_queryset(self):
        qs = Task.objects.filter(is_active=True).select_related(
            'assigned_to', 'vehicle', 'work_order', 'work_order__vehicle'
        )
        vehicle_id = self.request.query_params.get('vehicle')
        if vehicle_id:
            qs = qs.filter(vehicle_id=vehicle_id)
        return qs

    def perform_create(self, serializer):
        """
        Umjesto direktnog serializer.save(), pozivamo servis.
        Proslijeđujemo validirane podatke (dict) i korisnika.
        """
        try:
            entry = TaskService.create_task_entry(
                data=serializer.validated_data,
                user=self.request.user)
            serializer.instance = entry
        except ValidationError as e:
            # Ponovno podižemo iznimku kako bi DRF ispravno vratio 400 Bad Request
            logger.warning(f"Validacijska greška pri kreiranju zadatka od strane {self.request.user}: {e}")
            raise e

    def perform_update(self, serializer):
        """
        Servis obavlja biznis logiku (validaciju/modifikaciju), 
        a serializer.save() finalizira zapis.
        """
        # Servis sada samo modificira instancu u memoriji
        TaskService.update_task_entry(
            instance=serializer.instance,
            data=serializer.validated_data,
            user=self.request.user
        )
        # Sada DRF sigurno sprema izmijenjenu instancu
        serializer.save()
    
    def perform_destroy(self, instance):
        """
        Umjesto fizičkog brisanja, radimo soft-delete ako je potrebno.
        """
        instance.is_active = False
        instance.save()
        logger.info(f"Zapis zadatka {instance.id} je deaktiviran od strane {self.request.user}")