import csv
import io

from rest_framework.views import APIView
from drf_yasg.utils import swagger_auto_schema
from drf_yasg import openapi
from .serializers import ExportModelSerializer
from rest_framework.response import Response
from django.http import HttpResponse
import openpyxl
from django.apps import apps
from rest_framework import status
from django.shortcuts import render
from rest_framework import viewsets

from .serializers import ExportModelSerializer


def export_model_to_csv(request, model_name, fields, filters=None):
	model = apps.get_model('datastage', model_name)
	queryset = model.objects.filter(**(filters or {})).values(*fields)
	response = HttpResponse(content_type='text/csv')
	response['Content-Disposition'] = f'attachment; filename="{model_name}.csv"'
	writer = csv.DictWriter(response, fieldnames=fields)
	writer.writeheader()
	for row in queryset:
		writer.writerow(row)
	return response

def export_model_to_excel(request, model_name, fields, filters=None):
	model = apps.get_model('datastage', model_name)
	queryset = model.objects.filter(**(filters or {})).values(*fields)
	wb = openpyxl.Workbook()
	ws = wb.active
	ws.append(fields)
	for row in queryset:
		ws.append([row[field] for field in fields])
	output = io.BytesIO()
	wb.save(output)
	output.seek(0)
	response = HttpResponse(output.read(), content_type='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')
	response['Content-Disposition'] = f'attachment; filename="{model_name}.xlsx"'
	return response

# Create your views here.
from rest_framework.views import APIView

class ExportModelView(APIView):
	my_tags = ['Reportes']

	@swagger_auto_schema(
		manual_parameters=[
			openapi.Parameter('model', openapi.IN_QUERY, description="Nombre del modelo (ejemplo: Registro500)", type=openapi.TYPE_STRING, required=True)
		],
		responses={200: openapi.Response('Campos disponibles', schema=openapi.Schema(
			type=openapi.TYPE_OBJECT,
			properties={
				'fields': openapi.Schema(type=openapi.TYPE_ARRAY, items=openapi.Items(type=openapi.TYPE_STRING))
			}
		))}
	)
	def get(self, request, *args, **kwargs):
		"""
		Devuelve los campos disponibles para el modelo solicitado.
		Ejemplo: /api/reports/exportmodel/?model=Registro500
		"""
		model_name = request.query_params.get('model')
		if not model_name:
			return Response({'error': 'model is required'}, status=status.HTTP_400_BAD_REQUEST)
		try:
			model = apps.get_model('datastage', model_name)
		except LookupError:
			return Response({'error': f'Model {model_name} not found'}, status=status.HTTP_404_NOT_FOUND)
		fields = [f.name for f in model._meta.fields]
		return Response({'fields': fields})

	@swagger_auto_schema(
		request_body=ExportModelSerializer,
		responses={200: 'Archivo generado (Excel o CSV)'}
	)
	def post(self, request, *args, **kwargs):
		model_name = request.data.get('model')
		fields = request.data.get('fields')
		filters = request.data.get('filters', {})
		export_type = request.data.get('type', 'csv')

		if not model_name or not fields:
			return Response({'error': 'model and fields are required'}, status=status.HTTP_400_BAD_REQUEST)

		if export_type == 'excel':
			return export_model_to_excel(request, model_name, fields, filters)
		else:
			return export_model_to_csv(request, model_name, fields, filters)