from rest_framework import status
from rest_framework.viewsets import ModelViewSet
from rest_framework.response import Response
from rest_framework.permissions import IsAuthenticated
from rest_framework.filters import SearchFilter, OrderingFilter
from django_filters.rest_framework import DjangoFilterBackend

from core.paginations.limit_offset import CustomLimitOffsetPagination

from apps.clients.models import Client
from apps.clients.api.serializers import (
    ClientSerializer,
    ClientCreateSerializer,
    ClientUpdateSerializer
)
from apps.clients.api.permissions import IsClientWorkspaceMember
from apps.clients.services.clients import create_client, update_client


class ClientViewSet(ModelViewSet):
    """
    API endpoints for managing clients within workspaces.
    """
    permission_classes = [IsAuthenticated, IsClientWorkspaceMember]
    pagination_class = CustomLimitOffsetPagination
    filter_backends = [DjangoFilterBackend, SearchFilter, OrderingFilter]
    filterset_fields = ("workspace", )
    search_fields = ("name", "notes")
    ordering_fields = ("name", "created_at", "updated_at")
    ordering = ("-updated_at", "-created_at")
    
    def get_queryset(self):
        """
        Returns active clients belonging to workspaces where the current user is an active member.
        """
        if getattr(self, "swagger_fake_view", False) or not self.request.user.is_authenticated:
            return Client.objects.none()

        return Client.objects.filter(
            workspace__memberships__user=self.request.user,
            workspace__memberships__is_active=True,
            is_deleted=False
        ).distinct()

    def get_serializer_class(self):
        """
        Selects the appropriate serializer based on the request action.
        """
        if self.action == "create":
            return ClientCreateSerializer
        elif self.action in ["update", "partial_update"]:
            return ClientUpdateSerializer
        return ClientSerializer

    def create(self, request, *args, **kwargs):
        """
        Creates a new client using the client service.
        """
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        
        client = create_client(
            user=request.user,
            workspace_id=serializer.validated_data["workspace_id"],
            name=serializer.validated_data["name"],
            notes=serializer.validated_data.get("notes", "")
        )
        
        output_serializer = ClientSerializer(client)
        return Response(output_serializer.data, status=status.HTTP_201_CREATED)

    def update(self, request, *args, **kwargs):
        """
        Updates an existing client using the client service.
        """
        partial = kwargs.pop("partial", False)
        client = self.get_object()
        
        serializer = self.get_serializer(data=request.data, partial=partial)
        serializer.is_valid(raise_exception=True)
        
        updated_client = update_client(
            client=client,
            name=serializer.validated_data.get("name"),
            notes=serializer.validated_data.get("notes")
        )
        
        output_serializer = ClientSerializer(updated_client)
        return Response(output_serializer.data, status=status.HTTP_200_OK)

    def destroy(self, request, *args, **kwargs):
        """
        Soft deletes a client.
        """
        client = self.get_object()
        client.is_deleted = True
        client.save(update_fields=["is_deleted", "updated_at"])
        return Response(status=status.HTTP_204_NO_CONTENT)