from rest_framework import viewsets, permissions, serializers
from rest_framework.permissions import BasePermission

class IsOwner(BasePermission):
    def has_object_permission (self, request, view, obj ):
        """Return 'True' if permission is granted, 'False' otherwise."""
        # TODO: If this is the 'way to go', we should consider adding the researcher reference to all models and save actions
        return obj.researcher == request.user.researcher or obj.study.researcher == request.user.researcher

class BaseReadOnlyViewSet(viewsets.ReadOnlyModelViewSet):
    permission_classes = [permissions.IsAuthenticated, IsOwner]

    # TODO: If this is the 'way to go', we should consider adding the researcher reference to all models and save actions
    def get_queryset(self):
        try:
            qs = self.queryset.filter(researcher = self.request.user.researcher)
        except:
            qs = self.queryset.filter(study__researcher = self.request.user.researcher)

        return qs

class BaseViewSet(viewsets.ModelViewSet):
    permission_classes = [permissions.IsAuthenticated, IsOwner]

    # TODO: If this is the 'way to go', we should consider adding the researcher reference to all models and save actions
    def get_queryset(self):
        try:
            qs = self.queryset.filter(researcher = self.request.user.researcher)
        except:
            qs = self.queryset.filter(study__researcher = self.request.user.researcher)

        return qs

class BaseHyperlinkedModelSerializer(serializers.HyperlinkedModelSerializer):
    # This ID field is handy to have.... Due to HyperlinkedModelSerializer we do not have this field by default
    id = serializers.ReadOnlyField()

    # Only show the researcher full name
    researcher = serializers.StringRelatedField()

    # Only show link to full researcher data
    #researcher = serializers.HyperlinkedRelatedField(view_name= 'api:v1:researcher-detail', read_only=True)

    # Show the full researcher information
    #researcher = ResearcherSerializer(read_only=True)