from django.db.models import Subquery, Sum, OuterRef
from rest_framework import status
from rest_framework.exceptions import ValidationError

from api.models import TtStaff, TtTagRelation, TtLocation, TtModule, TtPos
from api.translation import __
from api.utils import log_critical_error, get_exception_detail
from api.validator import BaseValidator
from api.views.admin.base import AdminApiBase

class PosList(AdminApiBase):
    def validate_request(self,request):
        rules = {
            "academic_term_id": "required|exists:api.TtAcademicTerm,id",
            "filter": "nullable",
            "page": "nullable",
            "per_page": "nullable",
            "sort_by": "nullable",
            "order_by": "nullable",
        }
        # if need rename field, can put here
        attribute = {
            # "email": __("attr.email"),
        }
        # validate id first, cause need get pos by id, if wrong id direct return error
        validator = BaseValidator(request.data,rules,attribute)
        error = validator.validate()
        if error:
            raise ValidationError(error)

    def post(self, request):
        try:
            self.api_log_skip_outgoing_data=True
            self.validate_request(request)

            data = self.get_data(request)
            response = data
            return self.api_response(data=response)
        except ValidationError as e:
            first_message = e.detail['error']
            errors = e.detail['errors']
            return self.api_response(error=first_message,errors=errors,code=status.HTTP_400_BAD_REQUEST)
        except Exception as e:
            e_details = get_exception_detail(e)
            log_critical_error(user_id=None,descr=e_details['descr'],url=e_details['url'],trace=e_details['trace'])
            return self.api_response(error=__("message.internal_server_error"),code=status.HTTP_500_INTERNAL_SERVER_ERROR)

    def get_data(self,request):
        # pos_module_group / 
        # module with activity, activity with student_set filter by pos_id
        pos_student_size_subquery = (
            TtPos.objects.filter(id=OuterRef('id'))
            .values('id')
            .annotate(
                total_size=Sum(
                    'ttposmodulegroup__ttposmodulegroupmodule__module__ttactivity__student_set__planned_size',
                    distinct=True
                )
            )
            .values('total_size')
        )

        # 2. Run the main query with the subquery annotated directly onto it
        pos = (
            TtPos.objects
            .filter(academic_term_id=request.data.get("academic_term_id"))
            .select_related("department", "academic_term")
            .prefetch_related("module_group", "tag__tag")
            .annotate(
                student_set_size=Subquery(pos_student_size_subquery)
            )
            .order_by(self.list_default_order_column)
        )
        pos = self.listing_filter(request, pos)
        paginated_details = self.listing_pagination(request, pos)
        total = paginated_details["total"]
        paginated_data = paginated_details["paginated_data"]
        page = paginated_details["page"]
        return_data=[]

        for val in paginated_data:
            real_size = val.student_set_size
            ignored = []

            data={}
            data["id"] = val.id
            data["code"] = val.code
            data["name"] = val.name
            data['desc'] = val.desc
            data['department'] = val.department.name if val.department else None
            data['department_id'] = val.department_id
            data['academic_term'] = val.academic_term.name if val.academic_term else None
            data['academic_term_id'] = val.academic_term_id
            data['planned_size'] = val.planned_size
            data['real_size'] = real_size
            data['max_credit'] = val.max_credit

            data['module_group'] = [
                {"id": module_group.id, "name": module_group.name}
                for module_group in val.module_group.all()
            ]
            data["tag"] = [
                {"id": tag.tag.id, "name": tag.tag.name}
                for tag in val.tag.all()
            ]

            for i in range(1,11):
                extra_data_field = f"extra_data_{i}"
                data[extra_data_field] = getattr(val,extra_data_field,None)

            return_data.append(data)

        return {
            "total": total,
            "page": page,
            "data": return_data,
        }