import datetime
import logging
import uuid
from functools import reduce

from decimal import Decimal
from django.conf import settings
from django.db import transaction
from django.shortcuts import redirect
from django.urls import reverse_lazy
from django.utils.translation import ugettext_lazy as _
from django.views.generic import ListView

from cart.models import Buying, Discount, Offer
from core.models import City
from core.views import ProtectedListView, ProtectedTemplateView, ProtectedView, ProtectedFormView, ProtectedBaseFormView

from .forms import (
    CartRemoveBuyingForm,
    DiscountForm,
    CartAddInlineForm, CartCheckoutForm,
    CartCheckoutBuyingForm)

logger = logging.getLogger(__name__)


class CartAddView(ProtectedBaseFormView):
    http_method_names = ('post',)
    form_class = CartAddInlineForm

    def get_success_url(self):
        return self.request.META.get('HTTP_REFERRER', reverse_lazy('products:product_list'))

    def form_valid(self, form):
        self.request.cart.add(offer_id=form.cleaned_data['offer'].product_id, quantity=form.cleaned_data['amount'])
        return super().form_valid(form)


class CartRemoveView(ProtectedBaseFormView):
    http_method_names = ('post',)
    model = Offer
    form_class = CartRemoveBuyingForm

    def get_success_url(self):
        return self.request.META.get('HTTP_REFERRER', reverse_lazy('products:product_list'))

    def form_valid(self, form):
        self.request.cart.remove(form.cleaned_data['offer'].product_id)
        return super().form_valid(form)


class CartView(ProtectedListView):
    model = Offer
    paginate_by = settings.DEFAULT_PAGE_AMOUNT
    context_object_name = 'offer_items'
    template_name = 'cart/cart.html'
    ordering = '-create_at'
    title = _('Корзина')

    def get_queryset(self):
        qs = super().get_queryset()
        return qs.filter(product__id__in=self.request.cart.keys())

    def get_total_price(self, object_list):
        return reduce(
            lambda initial, offer: initial + offer.price * Decimal(self.request.cart[offer.product_id]['quantity']),
            object_list,
            Decimal(0)
        )

    def get_total_cashback(self, object_list):
        return reduce(
            lambda initial, offer: initial + offer.cashback * Decimal(self.request.cart[offer.product_id]['quantity']),
            object_list,
            Decimal(0)
        )

    def get_context_data(self, *, object_list=None, **kwargs):
        context = super().get_context_data(object_list=object_list, **kwargs)
        context['title'] = self.title
        context['total_price'] = self.get_total_price(self.object_list)
        context['total_price_currency'] = context['total_cashback_currency'] = self.object_list.first().currency.sign if self.object_list.first() else ''
        context['total_cashback'] = self.get_total_cashback(self.object_list)
        return context


class CartCheckoutView(ProtectedFormView):
    http_method_names = ('get', 'post',)
    template_name = 'cart/checkout.html'
    form_class = CartCheckoutForm
    title = _('Оформление заказа')

    def get_form_kwargs(self):
        kwargs = super().get_form_kwargs()
        kwargs['initial'] = {
            'customer_name': self.request.user.profile.full_name,
            'customer_email': self.request.user.email,
            'phone': self.request.user.profile.phone,
            'customer_address': self.request.user.profile.address,
            'city': City.objects.filter(name=self.request.user.profile.city).first()
        }
        return kwargs


class CartConfirmView(ProtectedFormView):
    http_method_names = ('post',)
    template_name = 'cart/confirm.html'
    form_class = CartCheckoutForm
    title = _('Подтверждение заказа')

    def form_valid(self, form):
        if form.is_valid():
            try:
                with transaction.atomic():
                    form.save()
                    for item in self.request.cart:
                        buying_form = CartCheckoutBuyingForm(initial={
                            'offer': item,
                            'order': form.instance.order_code,
                            'amount': self.request.cart[item]['quantity']
                        })
                        buying_form.save(self.request.user)
                form.send_order_invoice(self.request)
                form.send_order_request(self.request)
                self.request.cart.clear()
            except Exception as e:
                logger.critical(e)

        return super().form_invalid(form)

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['title'] = self.title
        return context


class BuyingsHistory(ProtectedListView):
    model = Buying
    paginate_by = settings.DEFAULT_PAGE_AMOUNT
    context_object_name = 'bought_item_list'
    ordering = '-create_at'
    template_name = 'cart/bought_history.html'
    title = _('История покупок')

    def get_queryset(self):
        qs = super().get_queryset()
        return qs.filter(user=self.request.user)

    def get_context_data(self, *, object_list=None, **kwargs):
        context = super().get_context_data(object_list=object_list, **kwargs)
        context['title'] = self.title
        return context


class DiscountListView(ListView):
    template_name = 'cart/discount_list.html'
    model = Discount
    title = _('Акции / Cashback')

    def get_context_data(self, *, object_list=None, **kwargs):
        context = super().get_context_data(object_list=object_list, **kwargs)
        context['title'] = self.title
        return context


# Discount views # @TODO: TEST FOR PRODUCTION
class PointsApply(ProtectedTemplateView):
    http_method_names = ('post',)

    def dispatch(self, request, *args, **kwargs):
        super().dispatch(request, *args, **kwargs)
        self.request.session['points'] = True
        return redirect('cart:buyings')


class PointsRevoke(ProtectedView):
    http_method_names = ('post',)

    def dispatch(self, request, *args, **kwargs):
        super().dispatch(request, *args, **kwargs)
        self.request.session.pop('points', None)
        return redirect('cart:buyings')


class DiscountApply(ProtectedFormView):
    http_method_names = ('post',)

    form_class = DiscountForm

    def form_valid(self, form):
        now = datetime.now()
        code = form.cleaned_data['code']
        try:
            discount = Discount.objects.get(code__iexact=code,
                                            valid_from__lte=now,
                                            valid_to__gte=now,
                                            active=True)
            self.request.session['discount_id'] = discount.id
        except Discount.DoesNotExist:
            self.request.session['discount_id'] = None
        return super().form_valid(form)

    def get_success_url(self):
        return reverse_lazy('cart:buyings')


class CreateDiscount(ProtectedFormView):
    http_method_names = ('post',)

    form_class = DiscountForm

    def form_valid(self, form):
        now = datetime.now()
        Discount.objects.update_or_create(
            user=self.request.user,
            defaults={'code': str(uuid.uuid4()),
                      'valid_from': now,
                      'valid_to': now + datetime.timedelta(days=7),
                      'active': True}
        )
        return super().form_valid(form)

    def get_success_url(self):
        return reverse_lazy('cabinet:index')