import sys

from registrasion import forms

from registrasion import util

from registrasion.models import commerce

from registrasion.models import inventory

from registrasion.models import people

from registrasion.controllers.cart import CartController

from registrasion.controllers.credit_note import CreditNoteController

from registrasion.controllers.invoice import InvoiceController

from registrasion.controllers.product import ProductController

from registrasion.exceptions import CartValidationError

from collections import namedtuple

from django.conf import settings

from django.contrib.auth.decorators import login_required

from django.contrib.auth.decorators import user_passes_test

from django.contrib import messages

from django.core.exceptions import ObjectDoesNotExist

from django.core.exceptions import ValidationError

from django.http import Http404

from django.shortcuts import redirect

from django.shortcuts import render

_GuidedRegistrationSection = namedtuple(

    "GuidedRegistrationSection",

    (

        "title",

        "discounts",

        "description",

        "form",

    )

)

@util.all_arguments_optional

class GuidedRegistrationSection(_GuidedRegistrationSection):

    ''' Represents a section of a guided registration page.

    Attributes:

       title (str): The title of the section.

       discounts ([registrasion.contollers.discount.DiscountAndQuantity, ...]):

            A list of discount objects that are available in the section. You

            can display ``.clause`` to show what the discount applies to, and

            ``.quantity`` to display the number of times that discount can be

            applied.

       description (str): A description of the section.

       form (forms.Form): A form to display.

    '''

    pass

        voucher_section = GuidedRegistrationSection(

            title="Voucher Code",

            form=voucher_form,

        )

        profile_section = GuidedRegistrationSection(

            title="Profile and Personal Information",

            form=profile_form,

        )

        title = "Attendee information"

        current_step = 1

        sections.append(voucher_section)

        sections.append(profile_section)

    else:

        # We're selling products

        starting = attendee.guided_categories_complete.count() == 0

        # Get the next category

        cats = inventory.Category.objects

        if SESSION_KEY in request.session:

            _cats = request.session[SESSION_KEY]

            cats = cats.filter(id__in=_cats)

        else:

            cats = cats.exclude(

                id__in=attendee.guided_categories_complete.all(),

            )

        cats = cats.order_by("order")

        request.session[SESSION_KEY] = []

        if starting:

            # Only display the first Category

            title = "Select ticket type"

            current_step = 2

            cats = [cats[0]]

        else:

            # Set title appropriately for remaining categories

            current_step = 3

            title = "Additional items"

        all_products = inventory.Product.objects.filter(

            category__in=cats,

        ).select_related("category")

            available_products = set(ProductController.available_products(

                request.user,

                products=all_products,

            ))

            if len(available_products) == 0:

                # We've filled in every category

                attendee.completed_registration = True

                attendee.save()

                return next_step

            for category in cats:

                products = [

                    i for i in available_products

                    if i.category == category

                ]

                prefix = "category_" + str(category.id)

                p = _handle_products(request, category, products, prefix)

                products_form, discounts, products_handled = p

                section = GuidedRegistrationSection(

                    title=category.name,

                    description=category.description,

                    discounts=discounts,

                    form=products_form,

                )

                if products:

                    # This product category has items to show.

                    sections.append(section)

                    # Add this to the list of things to show if the form

                    # errors.

                    request.session[SESSION_KEY].append(category.id)

                    if request.method == "POST" and not products_form.errors:

                        # This is only saved if we pass each form with no

                        # errors, and if the form actually has products.

                        attendee.guided_categories_complete.add(category)

    if sections and request.method == "POST":

        for section in sections:

            if section.form.errors:

                break

        else:

            attendee.save()

            if SESSION_KEY in request.session:

                del request.session[SESSION_KEY]

            # We've successfully processed everything

            return next_step

    data = {

        "current_step": current_step,

        "sections": sections,

        "title": title,

        "total_steps": 3,

    }

    return render(request, "registrasion/guided_registration.html", data)

    )

    handled = True if request.POST else False

    if request.POST and form.is_valid():

        form.instance.attendee = attendee

        form.save()

    return form, handled

@login_required

def product_category(request, category_id):

    ''' Form for selecting products from an individual product category.

    Arguments:

        category_id (castable to int): The id of the category to display.

    Returns:

        redirect or render:

            If the form has been sucessfully submitted, redirect to

            ``dashboard``. Otherwise, render

            ``registrasion/product_category.html`` with data::

                {

                    "category": category,         # An inventory.Category for

                                                  # category_id

                    "discounts": discounts,       # A list of

                                                  # DiscountAndQuantity

                    "form": products_form,        # A form for selecting

                                                  # products

                    "voucher_form": voucher_form, # A form for entering a

                                                  # voucher code

                }

    '''

    PRODUCTS_FORM_PREFIX = "products"

    VOUCHERS_FORM_PREFIX = "vouchers"

    # Handle the voucher form *before* listing products.

    # Products can change as vouchers are entered.

    v = _handle_voucher(request, VOUCHERS_FORM_PREFIX)

    voucher_form, voucher_handled = v

    category_id = int(category_id)  # Routing is [0-9]+

    category = inventory.Category.objects.get(pk=category_id)

        products = ProductController.available_products(

            request.user,

            category=category,

        )

        if not products:

            messages.warning(

                request,

                "There are no products available from category: " + category.name,

            )

            return redirect("dashboard")

        p = _handle_products(request, category, products, PRODUCTS_FORM_PREFIX)

        products_form, discounts, products_handled = p

    if request.POST and not voucher_handled and not products_form.errors:

        # Only return to the dashboard if we didn't add a voucher code

        # and if there's no errors in the products form

        messages.success(

            request,

            "Your reservations have been updated.",

        )

        return redirect("dashboard")

    data = {

        "category": category,

        "discounts": discounts,

        "form": products_form,

        "voucher_form": voucher_form,

    }

    return render(request, "registrasion/product_category.html", data)

def _handle_products(request, category, products, prefix):

    ''' Handles a products list form in the given request. Returns the

    form instance, the discounts applicable to this form, and whether the

    contents were handled. '''

    current_cart = CartController.for_user(request.user)

    ProductsForm = forms.ProductsForm(category, products)

    # Create initial data for each of products in category

    items = commerce.ProductItem.objects.filter(

        product__in=products,

        cart=current_cart.cart,

    ).select_related("product")