from rest_framework import mixins, status, viewsets
from rest_framework.decorators import action
from rest_framework.permissions import AllowAny, IsAuthenticated
from rest_framework.response import Response

from .filters import (
    BillingPlanFilter,
    InvoiceFilter,
    PaymentGatewayFilter,
    PaymentTransactionFilter,
    SubscriptionFilter,
)
from .models import (
    BillingPlan,
    Invoice,
    PaymentGateway,
    PaymentTransaction,
    Subscription,
)
from .serializers import (
    BillingPlanSerializer,
    InvoiceSerializer,
    PaymentGatewaySerializer,
    PaymentTransactionSerializer,
    SubscribeSerializer,
    SubscriptionSerializer,
)


class PaymentGatewayViewSet(viewsets.ModelViewSet):
    queryset = PaymentGateway.objects.all()
    serializer_class = PaymentGatewaySerializer
    permission_classes = [IsAuthenticated]
    filterset_class = PaymentGatewayFilter

    def initial(self, request, *args, **kwargs):
        from infrasynth.features.services import FeatureService

        if not FeatureService().is_enabled("billing", user=request.user):
            from django.http import Http404

            raise Http404()
        super().initial(request, *args, **kwargs)

    def get_queryset(self):
        return PaymentGateway.objects.all()


class BillingPlanViewSet(mixins.ListModelMixin, mixins.RetrieveModelMixin, viewsets.GenericViewSet):
    queryset = BillingPlan.objects.filter(is_active=True)
    serializer_class = BillingPlanSerializer
    filterset_class = BillingPlanFilter

    def get_permissions(self):
        if self.action in ("list", "retrieve"):
            return [AllowAny()]
        return [IsAuthenticated()]

    def initial(self, request, *args, **kwargs):
        from infrasynth.features.services import FeatureService

        if not FeatureService().is_enabled("billing", user=request.user):
            from django.http import Http404

            raise Http404()
        super().initial(request, *args, **kwargs)

    def get_queryset(self):
        return BillingPlan.objects.filter(is_active=True).select_related("gateway")


class SubscriptionViewSet(viewsets.ModelViewSet):
    queryset = Subscription.objects.all()
    serializer_class = SubscriptionSerializer
    permission_classes = [IsAuthenticated]
    filterset_class = SubscriptionFilter

    def initial(self, request, *args, **kwargs):
        from infrasynth.features.services import FeatureService

        if not FeatureService().is_enabled("billing", user=request.user):
            from django.http import Http404

            raise Http404()
        super().initial(request, *args, **kwargs)

    def get_queryset(self):
        return Subscription.objects.select_related("plan", "gateway", "user").all()

    @action(detail=False, methods=["post"])
    def subscribe(self, request):
        ser = SubscribeSerializer(data=request.data)
        ser.is_valid(raise_exception=True)
        from .services import BillingService

        try:
            result, gateway = BillingService().create_checkout_session(
                ser.validated_data["plan_slug"],
                request.user,
                success_url=ser.validated_data.get("success_url"),
                cancel_url=ser.validated_data.get("cancel_url"),
            )
        except ValueError as exc:
            return Response({"detail": str(exc)}, status=status.HTTP_400_BAD_REQUEST)
        return Response(
            {
                "checkout_url": result.checkout_url,
                "session_id": result.session_id,
                "client_secret": result.client_secret,
                "gateway": gateway.slug,
                "plan_slug": ser.validated_data["plan_slug"],
            }
        )


class InvoiceViewSet(viewsets.ModelViewSet):
    queryset = Invoice.objects.all()
    serializer_class = InvoiceSerializer
    permission_classes = [IsAuthenticated]
    filterset_class = InvoiceFilter

    def initial(self, request, *args, **kwargs):
        from infrasynth.features.services import FeatureService

        if not FeatureService().is_enabled("billing", user=request.user):
            from django.http import Http404

            raise Http404()
        super().initial(request, *args, **kwargs)

    def get_queryset(self):
        return Invoice.objects.select_related("subscription", "gateway", "user", "pdf_file").all()


class PaymentTransactionViewSet(viewsets.ReadOnlyModelViewSet):
    queryset = PaymentTransaction.objects.all()
    serializer_class = PaymentTransactionSerializer
    permission_classes = [IsAuthenticated]
    filterset_class = PaymentTransactionFilter

    def initial(self, request, *args, **kwargs):
        from infrasynth.features.services import FeatureService

        if not FeatureService().is_enabled("billing", user=request.user):
            from django.http import Http404

            raise Http404()
        super().initial(request, *args, **kwargs)

    def get_queryset(self):
        return PaymentTransaction.objects.select_related("invoice", "gateway").all()


class WebhookViewSet(viewsets.GenericViewSet):
    permission_classes = [AllowAny]

    @action(detail=False, methods=["post"])
    def receive(self, request):
        gateway_slug = request.data.get("gateway_slug") or request.query_params.get("gateway_slug")
        gateway = (
            PaymentGateway.objects.filter(slug=gateway_slug, is_active=True).first()
            if gateway_slug
            else PaymentGateway.objects.filter(is_active=True).first()
        )
        if gateway is None:
            return Response(
                {"detail": "No active payment gateway found."},
                status=status.HTTP_404_NOT_FOUND,
            )

        from django.utils.module_loading import import_string

        try:
            gateway_cls = import_string(gateway.gateway_class)
            gateway_instance = gateway_cls(gateway.config)
            result = gateway_instance.handle_webhook(payload=request.data, headers=dict(request.headers))
        except Exception as exc:  # noqa: BLE001
            return Response(
                {"detail": f"Webhook processing failed: {exc}"},
                status=status.HTTP_400_BAD_REQUEST,
            )

        if not result.is_handled:
            return Response(
                {"status": "ignored", "event_type": result.event_type},
                status=status.HTTP_200_OK,
            )
        return Response({"status": "processed", "event_type": result.event_type, "data": result.data})