from rest_framework import viewsets, status
from rest_framework.decorators import action, api_view, permission_classes
from rest_framework.response import Response
from rest_framework.permissions import AllowAny, IsAuthenticated
from rest_framework.parsers import MultiPartParser, FormParser, JSONParser
from rest_framework.authtoken.models import Token
from django.shortcuts import get_object_or_404
from django.db.models import Q
from django.utils import timezone
from django.utils.dateparse import parse_datetime
from .models import ContactUs, Composition, Campaign, CompositionImage
from .serializers import (
    ContactUsSerializer,
    CompositionSerializer,
    CampaignSerializer,
    CompositionImageSerializer,
    AdminLoginSerializer,
)


@api_view(['POST'])
@permission_classes([AllowAny])
def admin_login(request):
    """
    Admin login with username and password.

    Returns an auth token to use as:
    Authorization: Token <token>
    """
    serializer = AdminLoginSerializer(data=request.data)
    serializer.is_valid(raise_exception=True)
    user = serializer.validated_data['user']
    token, _ = Token.objects.get_or_create(user=user)
    return Response({
        'token': token.key,
        'user': {
            'id': user.id,
            'username': user.username,
            'is_staff': user.is_staff,
            'is_superuser': user.is_superuser,
        },
    })


@api_view(['POST'])
@permission_classes([IsAuthenticated])
def admin_logout(request):
    """Delete the current admin auth token (logout)."""
    Token.objects.filter(user=request.user).delete()
    return Response({'detail': 'Logged out successfully.'})


@api_view(['GET'])
@permission_classes([IsAuthenticated])
def admin_me(request):
    """Return the currently authenticated admin user."""
    user = request.user
    return Response({
        'id': user.id,
        'username': user.username,
        'is_staff': user.is_staff,
        'is_superuser': user.is_superuser,
        'is_active': user.is_active,
    })


class ContactUsViewSet(viewsets.ModelViewSet):
    """
    ViewSet for ContactUs model.
    Provides CRUD operations for contact form submissions.
    """
    queryset = ContactUs.objects.all()
    serializer_class = ContactUsSerializer
    permission_classes = [AllowAny]  # Allow anyone to submit contact forms
    
    def get_permissions(self):
        """
        Override to allow GET (list, retrieve) and POST (create) for anyone.
        """
        if self.action in ['list', 'retrieve', 'create', 'by_category']:
            return [AllowAny()]
        return [IsAuthenticated()]
    
    @action(detail=False, methods=['get'])
    def by_category(self, request):
        """Get contacts filtered by category."""
        category = request.query_params.get('category', None)
        if category:
            contacts = self.queryset.filter(category=category)
            serializer = self.get_serializer(contacts, many=True)
            return Response(serializer.data)
        return Response(
            {'error': 'Category parameter is required.'},
            status=status.HTTP_400_BAD_REQUEST
        )


class CompositionViewSet(viewsets.ModelViewSet):
    """
    ViewSet for Composition model.

    Supports uploading one or more images at create/update time via the
    multipart ``uploaded_images`` field, with an optional ``main_image_index``
    to flag the main image. Extra actions allow adding images, choosing the
    main image, and deleting an image after creation.
    """
    queryset = Composition.objects.prefetch_related('images').all()
    serializer_class = CompositionSerializer
    permission_classes = [AllowAny]  # Public read access
    parser_classes = [MultiPartParser, FormParser, JSONParser]
    
    def get_permissions(self):
        """
        Override to allow GET (list, retrieve) and POST (create) for anyone.
        """
        if self.action in ['list', 'retrieve', 'create', 'by_created_at']:
            return [AllowAny()]
        return [IsAuthenticated()]
    
    def get_serializer_context(self):
        """Add request to serializer context for image URL generation."""
        context = super().get_serializer_context()
        context['request'] = self.request
        return context
    
    @action(detail=False, methods=['get'], url_path='by-created-at')
    def by_created_at(self, request):
        """Get compositions filtered by created_at date range."""
        from_param = request.query_params.get('from')
        to_param = request.query_params.get('to')

        if not from_param and not to_param:
            return Response(
                {'error': 'At least one of "from" or "to" query parameters is required.'},
                status=status.HTTP_400_BAD_REQUEST,
            )

        compositions = self.queryset

        if from_param:
            from_dt = parse_datetime(from_param)
            if from_dt is None:
                return Response(
                    {'error': 'Invalid "from" datetime. Use ISO 8601 format.'},
                    status=status.HTTP_400_BAD_REQUEST,
                )
            if timezone.is_naive(from_dt):
                from_dt = timezone.make_aware(from_dt)
            compositions = compositions.filter(created_at__gte=from_dt)

        if to_param:
            to_dt = parse_datetime(to_param)
            if to_dt is None:
                return Response(
                    {'error': 'Invalid "to" datetime. Use ISO 8601 format.'},
                    status=status.HTTP_400_BAD_REQUEST,
                )
            if timezone.is_naive(to_dt):
                to_dt = timezone.make_aware(to_dt)
            compositions = compositions.filter(created_at__lte=to_dt)

        serializer = self.get_serializer(compositions, many=True)
        return Response(serializer.data)
    
    def _composition_response(self, composition):
        """Return a fresh composition payload with up-to-date images."""
        composition = Composition.objects.prefetch_related('images').get(
            pk=composition.pk
        )
        return self.get_serializer(composition).data
    
    @action(detail=True, methods=['post'], url_path='add-images')
    def add_images(self, request, pk=None):
        """Add one or more images to an existing composition."""
        composition = self.get_object()
        serializer = self.get_serializer(
            composition, data=request.data, partial=True
        )
        serializer.is_valid(raise_exception=True)
        composition = serializer.save()
        return Response(self._composition_response(composition))
    
    @action(detail=True, methods=['post'], url_path='set-main-image')
    def set_main_image(self, request, pk=None):
        """Flag one of the composition's images as the main image."""
        composition = self.get_object()
        image_id = request.data.get('image_id')
        if image_id is None:
            return Response(
                {'error': 'image_id is required.'},
                status=status.HTTP_400_BAD_REQUEST
            )
        image = get_object_or_404(
            CompositionImage, pk=image_id, composition=composition
        )
        image.is_main = True
        image.save()  # model.save() unsets is_main on the other images
        return Response(self._composition_response(composition))
    
    @action(
        detail=True,
        methods=['delete'],
        url_path='images/(?P<image_id>[^/.]+)'
    )
    def delete_image(self, request, pk=None, image_id=None):
        """Delete a single image from the composition."""
        composition = self.get_object()
        image = get_object_or_404(
            CompositionImage, pk=image_id, composition=composition
        )
        image.delete()
        return Response(status=status.HTTP_204_NO_CONTENT)


class CampaignViewSet(viewsets.ModelViewSet):
    """
    ViewSet for Campaign model.
    Provides CRUD operations for campaigns.
    """
    queryset = Campaign.objects.all()
    serializer_class = CampaignSerializer
    permission_classes = [AllowAny]  # Public read access
    
    def get_permissions(self):
        """
        Override to allow GET (list, retrieve) and POST (create) for anyone.
        """
        if self.action in ['list', 'retrieve', 'create', 'active', 'upcoming', 'ended']:
            return [AllowAny()]
        return [IsAuthenticated()]
    
    def get_serializer_context(self):
        """Add request to serializer context for image URL generation."""
        context = super().get_serializer_context()
        context['request'] = self.request
        return context
    
    @action(detail=False, methods=['get'])
    def active(self, request):
        """Get all currently active campaigns."""
        now = timezone.now()
        active_campaigns = self.queryset.filter(
            start_time__lte=now,
            end_time__gte=now
        )
        serializer = self.get_serializer(active_campaigns, many=True)
        return Response(serializer.data)
    
    @action(detail=False, methods=['get'])
    def upcoming(self, request):
        """Get all upcoming campaigns."""
        now = timezone.now()
        upcoming_campaigns = self.queryset.filter(start_time__gt=now)
        serializer = self.get_serializer(upcoming_campaigns, many=True)
        return Response(serializer.data)
    
    @action(detail=False, methods=['get'])
    def ended(self, request):
        """Get all ended campaigns."""
        now = timezone.now()
        ended_campaigns = self.queryset.filter(end_time__lt=now)
        serializer = self.get_serializer(ended_campaigns, many=True)
        return Response(serializer.data)