from decimal import Decimal

from django.http import HttpResponseRedirect
from django.shortcuts import get_object_or_404, render
from django.contrib.auth.decorators import login_required
from django.contrib.auth.models import User
from django.contrib.auth.forms import UserCreationForm

from webshop.models import (Article,
                            Category,
                            ArticleStatus,
                            Person,
                            City,
                            Picture,
                            CartPosition,
                            ShoppingCart)
from webshop.forms import (RegistrationForm,
                           AddToCartForm,
                           CartForm)
from webshop.utils import (get_categories,
                           get_hidden_status_id,
                           process_article_prices)

from currencies.models import ExchangeRate, ExchangeRate_name
from currencies.forms import CurrenciesForm

def index(request):
    category_list = get_categories()
    currencies_form = CurrenciesForm
    article_view = True

    articles = Article.objects.all().exclude(status=get_hidden_status_id())
    return_values = process_article_prices(request, articles)
    articles_list = return_values['articles_list']
    currency_name = return_values['currency_name']

    return render(request,
                  'webshop/index.html',
                  {'category_list': category_list,
                   'articles_list': articles_list,
                   'currencies_form': currencies_form,
                   'article_view': article_view,
                   'currency_name': currency_name})


def articles_in_category(request, category_id):
    category_list = get_categories()
    selected_category = Category.objects.get(id=category_id)

    currencies_form = CurrenciesForm
    article_view = True

    articles = Article.objects.filter(
        category=selected_category.id).exclude(status=get_hidden_status_id())
    return_values = process_article_prices(request, articles)
    articles_list = return_values['articles_list']
    currency_name = return_values['currency_name']

    return render(request, 'webshop/category.html',
                  {'articles_list': articles_list,
                   'category_list': category_list,
                   'currencies_form': currencies_form,
                   'article_view': article_view,
                   'currency_name': currency_name,
                   'category': selected_category})


def article_details(request, article_id):
    category_list = get_categories()
    currencies_form = CurrenciesForm
    amount = AddToCartForm
    rate = ExchangeRate
    article_view = True
    currency_name = "CHF"

    if not 'currency' in request.session:
        request.session['currency'] = None

    article = get_object_or_404(Article, pk=article_id)
    picture_list = Picture.objects.filter(article=article_id)

    if request.method == 'POST':
        # hier wird das Currency dropdown bearbeitet:
        if 'currencies' in request.POST:
            currencies_form = CurrenciesForm(request.POST)
            if currencies_form.is_valid():
                cf = currencies_form.cleaned_data
                if cf['currencies']:
                    selection = cf['currencies']
                    request.session['currency'] = selection.id
                    currency_name = ExchangeRate_name.objects.get(
                        id=selection.id)
                else:
                    request.session['currency'] = None

        # hier wird der Artikel in den Wahrenkorb transferiert:
        if 'amount' in request.POST:
            amount = AddToCartForm(request.POST)
            if amount.is_valid():
                amount = amount.cleaned_data['amount']
                currency_id = request.session['currency']
                article = Article.objects.get(id=article_id)
                try:
                    # lookup if cart_id is already existent:
                    cart_id = ShoppingCart.objects.get(user=request.user)
                except:
                    # if cart_id is not existent create a cart:
                    cart_id = ShoppingCart.objects.create(user=request.user)
                    cart_id.save()
                if cart_id:
                    # check if the article is existent in cart already:
                    try:
                        article_amount = CartPosition.objects.get(
                            article=article_id)
                        new_amount = article_amount.amount + amount
                        # if article is in cart already update amount:
                        cart_position = CartPosition.objects.filter(
                            id=article_id).update(
                            amount=new_amount
                            )
                    except Exception as e:
                        # if the article is not in cart yet add full item:
                        cart_position = CartPosition.objects.create(
                            article=article,
                            amount=amount,
                            cart=ShoppingCart.objects.get(user=request.user)
                            )
                        cart_position.save()
                # write default value (1) to form field:
                amount = AddToCartForm()
        else:
            amount = AddToCartForm()

    if request.session['currency']:
        currency = request.session['currency']
        article.price_in_chf = rate.exchange(currency, article.price_in_chf)
        currency_name = ExchangeRate_name.objects.get(id=currency)

    return render(request, 'webshop/article_details.html',
                  {'article': article,
                   'category_list': category_list,
                   'currencies_form': currencies_form,
                   'article_view': article_view,
                   'currency_name': currency_name,
                   'picture_list': picture_list,
                   'amount': amount
                   })


@login_required
def profile(request):
    category_list = get_categories()
    person = Person.objects.get(user=request.user)
    return render(request, 'registration/profile.html',
                  {'person': person,
                   'category_list': category_list})


def registration(request):
    category_list = get_categories()
    if request.method == 'POST':
            profile_form = RegistrationForm(request.POST)
            user_form = UserCreationForm(request.POST)
            if (profile_form.is_valid() and user_form.is_valid()):
                with transaction.atomic():
                    pf = profile_form.cleaned_data
                    uf = user_form.cleaned_data
                    user = User.objects.create_user(uf['username'],
                                                    pf['email'],
                                                    uf['password2'])
                    user.last_name = pf['last_name']
                    user.first_name = pf['first_name']
                    user.save()
                    person = Person.objects.create(
                        salutation=pf['salutation'],
                        city=City.objects.get(zip_code=pf['zip_code'],
                                            name=pf['city']),
                        street_name=pf['street_name'],
                        street_number=pf['street_number'],
                        user=user)
                return HttpResponseRedirect('/login/')
    else:
        profile_form = RegistrationForm
        user_form = UserCreationForm
    return render(request, 'registration/register.html',
                  {'profile_form': profile_form,
                   'category_list': category_list,
                   'user_form': user_form})


def cart(request):
    category_list = get_categories()
    currencies_form = CurrenciesForm
    rate = ExchangeRate
    article_view = True
    message = ""
    cart_id = False
    totalprice_list = []
    total = 0

    if request.method == 'POST':
        if 'amount' in request.POST:
            print(request.POST)
            amount = CartForm.ChangeAmount(request.POST)
            if amount.is_valid():
                amount = amount.cleaned_data['amount']
                article = Article.objects.get(id=article_id)
                try:
                    cart_id = ShoppingCart.objects.get(user=request.user)
                except:
                    cart_id = ShoppingCart.objects.create(user=request.user)
                    cart_id.save()
                if cart_id:
                    cart_position = CartPosition.objects.create(
                        article=article,
                        amount=amount,
                        cart=ShoppingCart.objects.get(user=request.user)
                        )
                    cart_position.save()
                amount = CartForm.ChangeAmount()
        else:
            amount = AddToCartForm()
    # if the cart_id is set the user has already added items to cart.

    try:
        cart_id = ShoppingCart.objects.get(user=request.user)
    except Exception as e:
        message = "You have no items in the Basket"
        return render(request, 'webshop/cart.html',
                      {'currencies_form': currencies_form,
                       'article_view': article_view,
                       'currency_name': "CHF",
                       'category_list': category_list,
                       'message': message})

    articles = []
    cart_position = CartPosition.objects.filter(cart=cart_id)
    cart_position_list = list(cart_position)
    for idx, cart_position in enumerate(cart_position_list):
            articles.append(cart_position.article)

    return_values = process_article_prices(request, articles)
    articles_list = return_values['articles_list']
    currency_name = return_values['currency_name']

    for idx, cart_position in enumerate(cart_position_list):
        cart_position.calculate_position_price()
        cart_position.article = articles_list[idx]
        totalprice_list.append(cart_position.position_price)

    total = sum(totalprice_list)
    return render(request, 'webshop/cart.html',
                {'articles_list': articles_list,
                'totalprice_list': totalprice_list,
                'cart_position_list': cart_position_list,
                'total': total,
                'currencies_form': currencies_form,
                'article_view': article_view,
                'currency_name': currency_name,
                'category_list': category_list,
                'message': message,
                })