"""
API формы Ф-2.

Содержит:
- FormF2UploadView - загрузка файла
- FormF2RecordViewSet - просмотр записей
"""

import logging

from apps.core.upload_contracts import (
    build_upload_error_response,
    build_upload_success_payload,
    build_upload_validation_response,
)
from apps.core.viewsets import ReadOnlyViewSet
from apps.form_2.models import FormF2Record
from apps.form_2.serializers import (
    FormF2ParseResultSerializer,
    FormF2RecordListSerializer,
    FormF2RecordSerializer,
    FormF2UploadSerializer,
)
from apps.form_2.services import parse_form_f2_file
from apps.form_2.tasks import process_form_f2_file
from rest_framework import status
from rest_framework.parsers import MultiPartParser
from rest_framework.permissions import IsAuthenticated
from rest_framework.response import Response
from rest_framework.views import APIView

logger = logging.getLogger(__name__)

# Порог для фоновой обработки (байты)
BACKGROUND_THRESHOLD = 1024 * 1024  # 1MB


class FormF2UploadView(APIView):
    """
    Загрузка файла формы Ф-2.

    POST /api/v1/forms/f2/upload/
    """

    parser_classes = [MultiPartParser]

    def post(self, request):
        """Загрузка и обработка файла."""
        serializer = FormF2UploadSerializer(data=request.data)

        if not serializer.is_valid():
            return build_upload_validation_response(serializer.errors)

        file = serializer.validated_data["file"]
        report_year = serializer.validated_data["report_year"]
        report_quarter = serializer.validated_data.get("report_quarter")

        # Для больших файлов - фоновая обработка
        if file.size > BACKGROUND_THRESHOLD:
            file_content = file.read()
            task = process_form_f2_file.delay(
                file_content,
                file.name,
                report_year,
                report_quarter,
            )

            return Response(
                build_upload_success_payload(
                    form="f2",
                    report_year=report_year,
                    report_quarter=report_quarter,
                    status="queued",
                    job_id=task.id,
                ),
                status=status.HTTP_202_ACCEPTED,
            )

        # Синхронная обработка
        try:
            result = parse_form_f2_file(
                file,
                report_year=report_year,
                report_quarter=report_quarter,
            )
            result_serializer = FormF2ParseResultSerializer(result)

            return Response(
                build_upload_success_payload(
                    form="f2",
                    report_year=report_year,
                    report_quarter=report_quarter,
                    status="done",
                    result=result_serializer.data,
                ),
                status=status.HTTP_200_OK,
            )
        except Exception as e:
            logger.exception("Ошибка обработки файла Ф-2")
            return build_upload_error_response(
                error_code="processing_error",
                error_message=str(e),
                status_code=status.HTTP_400_BAD_REQUEST,
            )


class FormF2RecordViewSet(ReadOnlyViewSet[FormF2Record]):
    """
    ViewSet для записей формы Ф-2.

    GET /api/v1/forms/f2/records/ - список записей
    GET /api/v1/forms/f2/records/{id}/ - детали записи
    """

    queryset = FormF2Record.objects.select_related("organization").filter(
        is_active_version=True
    )
    serializer_class = FormF2RecordSerializer
    permission_classes = [IsAuthenticated]

    def get_serializer_class(self):
        """Выбор сериализатора в зависимости от действия."""
        if self.action == "list":
            return FormF2RecordListSerializer
        return FormF2RecordSerializer

    def get_queryset(self):
        """Фильтрация по batch_id."""
        queryset = super().get_queryset()
        batch_id = self.request.query_params.get("batch_id")
        report_year = self.request.query_params.get("report_year")
        report_quarter = self.request.query_params.get("report_quarter")
        if batch_id:
            queryset = queryset.filter(load_batch=batch_id)
        if report_year:
            queryset = queryset.filter(report_year=report_year)
        if report_quarter:
            queryset = queryset.filter(report_quarter=report_quarter)
        return queryset