# operations/views.py
from django.http import HttpResponse
from django.utils import timezone
from django_filters.rest_framework import DjangoFilterBackend
from rest_framework import viewsets, filters, permissions, status
from rest_framework.views import APIView
from rest_framework.decorators import action
from rest_framework.response import Response

from .models import RadniNalog, RadniNalogSlika, PutniNalog
from .mixins import AstroBridgeViewSetMixin 
from .services import izvrsi_perform_create_logiku, get_optimized_image
from .serializers import (
    RadniNalogSerializer, 
    RadniNalogDetaljiSerializer,
    KreirajPutniNalogSerializer,
    PutniNalogSerializer
)

class RadniNalogViewSet(AstroBridgeViewSetMixin, viewsets.ModelViewSet):
    queryset = RadniNalog.objects.all().select_related(
        'klijent', 'izvrsitelj', 'putni_nalog__vozilo'
    )
    
    auto_handle_files = True                
    file_field_name = 'slike'               
    related_file_model = RadniNalogSlika    
    related_file_fk = 'radni_nalog'         

    filter_backends = [
        DjangoFilterBackend, 
        filters.SearchFilter, 
        filters.OrderingFilter
    ]
    
    filterset_fields = ['status', 'izvrsitelj', 'klijent', 'putni_nalog__vozilo']
    search_fields = ['broj_naloga', 'klijent__naziv', 'putni_nalog__vozilo__registracija', 'putni_nalog__vozilo__naziv']
    ordering_fields = ['datum_kreiranja', 'status', 'broj_naloga']
    ordering = ['-datum_kreiranja']

    def get_serializer_class(self):
        if self.action in ['create', 'update', 'partial_update']:
            return RadniNalogSerializer
        return RadniNalogDetaljiSerializer

    def get_queryset(self):
        queryset = self.queryset
        if self.action in ['list', 'retrieve']:
            queryset = queryset.prefetch_related('slike')
        return queryset

    def perform_create(self, serializer):
        # Delegiramo izvršavanje u operacije.py
        return izvrsi_perform_create_logiku(serializer, self.request.user)

    def create(self, request, *args, **kwargs):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        
        instance = self.perform_create(serializer)
        instance.refresh_from_db()
        
        izlazni_serializer = RadniNalogDetaljiSerializer(instance, context={'request': request})
        return Response(izlazni_serializer.data, status=status.HTTP_201_CREATED)

    def update(self, request, *args, **kwargs):
        partial = kwargs.pop('partial', True)
        instance = self.get_object()
        
        serializer = RadniNalogSerializer(instance, data=request.data, partial=partial)
        serializer.is_valid(raise_exception=True)
        
        self.perform_update(serializer)
        instance.refresh_from_db()
        
        return Response(RadniNalogDetaljiSerializer(instance, context={'request': request}).data)

    @action(detail=False, methods=['get'], url_path='sljedeci-broj', permission_classes=[permissions.AllowAny])
    def dohvati_sljedeci_broj(self, request):
        godina = timezone.now().year
        kljuc_sekvence = f"radni_nalog_{godina}"
        prefix = f"RN-{godina}-"
        
        from .models import BrojacSekvence
        brojac = BrojacSekvence.objects.filter(naziv_sekvence=kljuc_sekvence).first()
        
        if brojac:
            sljedeci_broj = brojac.zadnji_broj + 1
        else:
            zadnji_nalog = RadniNalog.objects.filter(broj_naloga__startswith=prefix).order_by('-broj_naloga').first()
            if zadnji_nalog:
                try:
                    sljedeci_broj = int(zadnji_nalog.broj_naloga.split('-')[-1]) + 1
                except (ValueError, IndexError):
                    sljedeci_broj = 1
            else:
                sljedeci_broj = 1
                
        sljedeci_broj_formatiran = f"{prefix}{sljedeci_broj:04d}"
        return Response({"broj_naloga": sljedeci_broj_formatiran})


class PutniNalogViewSet(AstroBridgeViewSetMixin, viewsets.ModelViewSet):
    queryset = PutniNalog.objects.all().order_by('-datum_izdavanja', '-id')
    permission_classes = [permissions.IsAuthenticated]

    def get_serializer_class(self):
        if self.action == 'create':
            return KreirajPutniNalogSerializer
        return PutniNalogSerializer

    def create(self, request, *args, **kwargs):
        serializer = self.get_serializer(data=request.data, context={'request': request})
        serializer.is_valid(raise_exception=True)
        
        putni_nalog = serializer.save()
        
        return Response(
            {
                "id": putni_nalog.id,
                "broj_naloga": putni_nalog.broj_naloga,
                "status": putni_nalog.status,
                "pocetna_km": putni_nalog.pocetna_km,
                "message": "Putni nalog uspješno kreiran!"
            }, 
            status=status.HTTP_201_CREATED
        )
    

class ProxyImageView(APIView):
    http_method_names = ['get']
    permission_classes = [permissions.AllowAny]

    def get(self, request):
        image_url = request.query_params.get('url')
        
        try:
            width = int(request.query_params.get('w', 600)) # Defaultna širina za terensku karticu
        except (ValueError, TypeError):
            width = 600
        
        if not image_url:
            return Response({"error": "URL slike nije zadan"}, status=status.HTTP_400_BAD_REQUEST)
            
        try:
            # get_optimized_image vraća sirove binarne bajtove WebP slike iz BytesIO-a
            image_data = get_optimized_image(image_url, width=width)
            
            response = HttpResponse(image_data, content_type="image/webp")
            # 🚀 KLJUČNO ZA OFFLINE I BRZINU: Kažemo pregledniku da kešira sliku na 7 dana
            response['Cache-Control'] = 'public, max-age=604800, immutable'
            return response
        except Exception as e:
            print(f"[ProxyImageView Krah] Detalji: {e}")
            return Response({"error": f"Greška pri optimizaciji: {str(e)}"}, status=status.HTTP_500_INTERNAL_SERVER_ERROR)