import prometheus_client
from rest_framework.views import APIView
from rest_framework.permissions import AllowAny
from django.http import HttpResponse, HttpResponseNotFound
from django.utils.decorators import method_decorator
from django.views.decorators.cache import cache_page
from django.conf import settings

from labs.prometheus.metrics import update_metrics
from labs.utils.network import get_client_ip


class PrometheusMetricsView(APIView):
    permission_classes = (AllowAny,)

    @method_decorator(cache_page(timeout=10))
    def get(self, request, *args, **kwargs):
        # Only allow access from trusted IPs or staff users.
        if not (
            request.user and request.user.is_authenticated and request.user.is_staff
        ):
            ip, _ = get_client_ip(request)
            if ip not in settings.PROMETHEUS_TRUSTED_IPS:
                return HttpResponseNotFound()

        update_metrics()

        return HttpResponse(
            prometheus_client.generate_latest(),
            content_type=prometheus_client.CONTENT_TYPE_LATEST,
        )