from rest_framework import viewsets, mixins, permissions

from apps.compliance.permissions import IsAdmin

from .models import User
from .serializers import UserSerializer, UserDetailSerializer, UserCreateSerializer


class UserViewSet(mixins.ListModelMixin,
                  mixins.RetrieveModelMixin,
                  mixins.UpdateModelMixin,
                  viewsets.GenericViewSet):
    queryset = User.objects.all()
    serializer_class = UserSerializer
    # A signed-in user may read their own record (get_queryset scopes a
    # non-admin to it) but must not be able to write one. Without this, a buyer
    # could PATCH their own row and set role to "admin", which would then pass
    # every IsOpsOrAdmin check on the platform. Role and is_active are read-only
    # in the serializer as well, so no API caller can change them.
    permission_classes = [permissions.IsAuthenticated]

    def get_permissions(self):
        if self.action in ("create", "update", "partial_update", "destroy"):
            return [IsAdmin()]
        return super().get_permissions()

    def get_serializer_class(self):
        if self.action == "retrieve":
            return UserDetailSerializer
        if self.action == "create":
            return UserCreateSerializer
        return UserSerializer

    def get_queryset(self):
        user = self.request.user
        if user.role == "admin":
            return User.objects.all()
        return User.objects.filter(id=user.id)