from django.core.paginator import Paginator, PageNotAnInteger, EmptyPage
from django.shortcuts import get_object_or_404, redirect
from django.views.generic import *
from .models import *
from store.cart import Cart, CartItem
from django.contrib import messages


class CategoryBaseView(object):
    category = None

    def _get_full_category(self, categories_string):
        cats = categories_string.split('/')
        category = get_object_or_404(Category, slug=cats[0])
        for c in cats:
            if c != category.slug:
                category = get_object_or_404(category.childs, slug=c)
        return category


class CategoryView(CategoryBaseView, TemplateView):
    template_name = 'category.jinja'
    brand_pks = []
    products_qs = None
    sort = None
    ORDER_PARAMETERS = (
        ('date', 'pk'),
        ('-date', '-pk'),
        ('price', 'price_min'),
        ('-price', '-price_min'),
    )

    def _get_brand_pks(self):
        brand_pks = []

        for v in self.request.GET.getlist('brand[]'):
            try:
                brand_pks.append(int(v))
            except:
                pass

        return brand_pks

    def _get_sort(self):
        sort = self.request.GET.get('sort', None)

        return sort

    def paginate(self):
        paginate_by = self.request.GET.get('paginate_by', 10)

        if paginate_by == 'all':
            paginate_by = 10000

        paginator = Paginator(self.products_qs, int(paginate_by))
        page = self.request.GET.get('page')
        try:
            self.products_qs = paginator.page(page)
        except PageNotAnInteger:
            self.products_qs = paginator.page(1)
        except EmptyPage:
            self.products_qs = paginator.page(paginator.num_pages)

    def _get_filter_attributes(self):

        for k in self.request.GET:
            attr = Attribute.objects.filter(slug=k.replace('[]', ''))
            if attr:
                attr_values = self.request.GET.getlist(k)
                while 'false' in attr_values:
                    attr_values.remove('false')
                attr_values = [v.strip() for v in attr_values]
                if attr_values:
                    self.products_qs = self.products_qs.filter(
                        product_attributes__attribute__attribute__in=attr,
                        product_attributes__value__in=attr_values).distinct()

    def get_context_data(self, **kwargs):
        retval = super(CategoryView, self).get_context_data()
        self.category = self._get_full_category(kwargs['categories'])
        self.products_qs = self.category.get_all_products().order_by('-pk')
        self.brand_pks = self._get_brand_pks()
        self.sort = self._get_sort()

        if self.brand_pks:
            self.products_qs = self.products_qs.filter(
                brand__pk__in=self.brand_pks)

        if self.sort:
            sort_parameter = dict(self.ORDER_PARAMETERS)[self.sort]
            preordered_qs = self.products_qs

            if sort_parameter in ['price_min', '-price_min']:
                preordered_qs = self.products_qs.extra(
                    select={
                        'price_min':
                        'SELECT MIN(price) FROM store_productvariation ' +
                        'WHERE store_productvariation.product_id ' +
                        '= store_product.id'
                    })

            self.products_qs = preordered_qs.order_by(sort_parameter)

        self._get_filter_attributes()

        self.paginate()
        retval['category'] = self.category
        retval['products'] = self.products_qs
        return retval


class ProductView(CategoryBaseView, DetailView):
    model = Product
    template_name = 'product.jinja'

    def get(self, request, *args, **kwargs):
        self.category = self._get_full_category(kwargs['categories'])
        retval = super(ProductView, self).get(request, args, kwargs)
        return retval

    def get_context_data(self, **kwargs):
        retval = super(ProductView, self).get_context_data()
        retval['category'] = self.category
        return retval


class CartAddView(RedirectView):

    def dispatch(self, request, *args, **kwargs):
        retval = super(CartAddView, self).dispatch(request, args, kwargs)
        cart = Cart(self.request)
        item_variant = ProductVariation.objects.get(
            pk=self.request.GET.get('pk'))
        count = self.request.GET.get('count')
        messages.success(
            self.request, """Товар успешно добавлен в корзину!
            Вы можете перейти к оформлению заказа,
            либо продолжить выбор товаров.
            <a href='/store/cart/'>Открыть корзину...</a>""")
        cart.add_item(CartItem(item_variant, count))
        return retval

    def get_redirect_url(self, *args, **kwargs):
        return self.request.GET.get('next', '/')


class CartRemoveView(RedirectView):

    def dispatch(self, request, *args, **kwargs):
        retval = super(CartRemoveView, self).dispatch(request, args, kwargs)
        cart = Cart(self.request)
        item_id = self.request.GET.get('id')
        cart.remove_item(item_id)
        return retval

    def get_redirect_url(self, *args, **kwargs):
        return '/store/cart/'


class CartDetailView(TemplateView):
    template_name = 'cart_detail.jinja'

    def get_context_data(self, **kwargs):
        retval = super(CartDetailView, self).get_context_data()
        retval['cart'] = Cart(self.request)
        return retval

    def post(self, request, *args, **kwargs):
        cart = Cart(self.request)
        cart.update_items()
        return redirect(self.request.path)