from django.db import models
from rest_framework import viewsets, serializers, routers


class Country(models.Model):
    name = models.CharField(max_length=100)
    population = models.PositiveIntegerField()


class CountrySerializer(serializers.ModelSerializer):
    class Meta:
        model = Country
        fields = "__all__"


class CountryCreateSerializer(serializers.ModelSerializer):
    class Meta:
        model = Country
        fields = ("name",)


class CountryViewSet(viewsets.ModelViewSet):
    queryset = Country.objects.all()
    serializer_class = CountrySerializer

    def get_serializer_class(self):
        if self.action == "create":
            return CountryCreateSerializer
        return super().get_serializer_class()


router = routers.DefaultRouter()
router.register(r"country", CountryViewSet)


urlpatterns = router.urls

class DynamicSerializerMetadata(SimpleMetadata):
    def determine_actions(self, request, view):
        actions = {}
        for method in {"PUT", "POST"} & set(view.allowed_methods):
            view.request = clone_request(request, method)
            try:
                # Test global permissions
                if hasattr(view, "check_permissions"):
                    view.check_permissions(view.request)
                # Test object permissions
                if method == "PUT" and hasattr(view, "get_object"):
                    view.get_object()
            except (exceptions.APIException, PermissionDenied, Http404):
                pass
            else:
                # If user has appropriate permissions for the view, include
                # appropriate metadata about the fields that should be supplied.

                view.action =  view.action_map.get(method.lower())  # <----- SET TO CORRECT ACTION BEFORE CALLING get_serializer
                serializer = view.get_serializer()
                view.action = "metadata" # <------ RESTORE
                actions[method] = self.get_serializer_info(serializer)
            finally:
                view.request = request
        
        return actions