import logging
import csv
import datetime
import operator
from functools import reduce

from django.shortcuts import render
from django.conf import settings
from django.db.models import Q

# Create your views here.
from rest_framework import status
from rest_framework import viewsets
from rest_framework.response import Response
from rest_framework.permissions import IsAuthenticatedOrReadOnly, IsAdminUser, IsAuthenticated
from rest_framework.decorators import api_view, permission_classes, action
import django_filters.rest_framework

import requests

from products.models import Product
from products.serializers import ProductSerializer, TagFilterSerializer
from companies.models import Company
from history.models import HistorySync

from back_latienda.permissions import IsCreator
from .utils import extract_search_filters
from utils.tag_serializers import TaggitSerializer
from utils.tag_filters import ProductTagFilter


logging.basicConfig(
    filename='logs/product-load.log',
    filemode='w',
    format='%(levelname)s:%(message)s',
    level=logging.INFO,
    )


class ProductViewSet(viewsets.ModelViewSet):
      queryset = Product.objects.all()
      serializer_class = ProductSerializer
      permission_classes = [IsAuthenticatedOrReadOnly, IsCreator]
      filter_backends = ProductTagFilter
      filterset_fields = ['name', 'tags']

      def perform_create(self, serializer):
            serializer.save(creator=self.request.user)

      @action(detail=True, methods=['GET',])
      def related(request):
            # find the most similar products
            return Response(data=[])


@api_view(['GET',])
@permission_classes([IsAuthenticated,])
def my_products(request):
      qs = Product.objects.filter(creator=request.user)
      product_serializer = ProductSerializer(qs)
      return Response(data=product_serializer.data)


@api_view(['POST',])
@permission_classes([IsAuthenticated,])
def load_coop_products(request):
      """Read CSV file being received
      Parse it to create products for related Company
      """
      try:
            csv_file = request.FILES['csv_file']
            if csv_file.name.endswith('.csv') is not True:
                  logging.error(f"File {csv_file.name} is not a CSV file")
                  return Response({"errors":{"details": "File is not CSV type"}})

            logging.info(f"Reading contents of  {csv_file.name}")
            decoded_file = csv_file.read().decode('utf-8').splitlines()
            csv_reader =  csv.DictReader(decoded_file, delimiter=',')
            counter = 0
            # get company linked to user
            company_qs = Company.objects.filter(creator=request.user)

            if company_qs:
                  company = company_qs.first()
            else:
                  return Response({"errors":{"details": "Your user has no company to add products to"}})
            # create historysync instance
            history = HistorySync.objects.create(company=company, sync_date=datetime.datetime.now(), quantity=len(decoded_file))

            for row in csv_reader:
                  if '' in (row['nombre-producto'], row['descripcion'], row['precio'], row['categoria']):
                        logging.error(f"Required data missing: {row}")
                        continue
                  try:
                        # download image references in csv
                        if row['imagen'].strip() != '':
                              image_url = row['imagen'].strip()
                              response = requests.get(image_url, stream=True)
                              if response.status_code == 200:
                                    path = f"{setting.BASE_DIR}media/{row['nombre-producto'].strip()}.{image.url.split('/')[-1]}"
                                    logging.info(f"Saving product image to: {path}")
                                    new_image = open(path, 'wb')
                                    for chunk in response:
                                          new_image.write(chunk)
                                    new_image.close()
                              else:
                                    logging.warning(f"Image URL did not work: {image_url}")
                                    new_image = None
                        else:
                              new_image = None

                        # TODO: if tags is empty, auto-generate tags

                        # assemble instance data
                        product_data = {
                              'id': None if row['id'].strip()=='' else row['id'].strip(),
                              'company': Company.objects.filter(creator=request.user).first(),
                              'name': row['nombre-producto'].strip(),
                              'description': row['descripcion'].strip(),
                              'image': new_image,
                              'url': row['url'].strip(),
                              'price': row['precio'].strip(),
                              'shipping_cost': row['gastos-envio'].strip(),
                              'shipping_terms': row['cond-envio'].strip(),
                              'discount': row['descuento'].strip(),
                              'stock': row['stock'].strip(),
                              'tags': row['tags'].strip(),
                              'category': row['categoria'].strip(),
                              'identifiers': row['identificadores'].strip(),
                              'history': history,
                              'creator': request.user,
                        }

                        Product.objects.create(**product_data)
                        logging.info(f"Created Product: {product_data}")
                        counter += 1
                  except Exception as e:
                        logging.error(f"Could not parse {row}")
            return Response()
      except Exception as e:
            return Response({"errors": {"details": str(type(e))}}, status=status.HTTP_500_INTERNAL_SERVER_ERROR)


@api_view(['GET',])  # include allowed methods
def product_search(request):
      """
      Takes a string of data, return relevant products
      """
      query_string = request.GET.get('query_string', None)
      if query_string is None:
            return Response({"errors": {"details": "No query string to parse"}})
      try:
            # save results
            result_set = set()
            # split query string into single words
            chunks = query_string.split(' ')

            for chunk in chunks:
                  # search inside name and description
                  products = Product.objects.filter(Q(name__icontains=chunk) | Q(description__icontains=chunk))
                  for item in products:
                        result_set.add(item)

                  # search in tags
                  products = Product.objects.filter(tags=chunk)
                  for item in products:
                        result_set.add(item)
                  # search in category
                  products = Product.objects.filter(category=chunk)
                  for item in products:
                        result_set.add(item)
                  # search in attributes
                  products = Product.objects.filter(attributes=chunk)
                  for item in products:
                        result_set.add(item)
            # extract filters from result_set
            filters = extract_search_filters(result_set)
            # serialize and respond
            product_serializer = ProductSerializer(result_set, many=True)
            return Response(data={"filters": filters, "products": product_serializer.data})
      except Exception as e:
            return Response({"errors": {"details": str(type(e))}}, status=status.HTTP_500_INTERNAL_SERVER_ERROR)