from __future__ import unicode_literals

import datetime

import itertools

from django.core.exceptions import ValidationError

from django.contrib.auth.models import User

from django.db import models

from django.db.models import F, Q

from django.utils import timezone

from django.utils.encoding import python_2_unicode_compatible

from django.utils.translation import ugettext_lazy as _

from model_utils.managers import InheritanceManager

# User models

@python_2_unicode_compatible

class Attendee(models.Model):

    ''' Miscellaneous user-related data. '''

    def __str__(self):

        return "%s" % self.user

    @staticmethod

    def get_instance(user):

        ''' Returns the instance of attendee for the given user, or creates

        a new one. '''

        attendees = Attendee.objects.filter(user=user)

        if len(attendees) > 0:

            return attendees[0]

        else:

            attendee = Attendee(user=user)

            attendee.save()

            return attendee

    user = models.OneToOneField(User, on_delete=models.CASCADE)

    # Badge/profile is linked

    completed_registration = models.BooleanField(default=False)

    highest_complete_category = models.IntegerField(default=0)

class AttendeeProfileBase(models.Model):

    ''' Information for an attendee's badge and related preferences.

    Subclass this in your Django site to ask for attendee information in your

    registration progess.

     '''

    @classmethod

    def name_field(cls):

        ''' This is used to pre-fill the attendee's name from the

        speaker profile. If it's None, that functionality is disabled. '''

        return None

    attendee = models.OneToOneField(Attendee, on_delete=models.CASCADE)

# Inventory Models

@python_2_unicode_compatible

class Category(models.Model):

    ''' Registration product categories '''

    class Meta:

        verbose_name_plural = _("categories")

    def __str__(self):

        return self.name

    RENDER_TYPE_RADIO = 1

    RENDER_TYPE_QUANTITY = 2

    CATEGORY_RENDER_TYPES = [

        (RENDER_TYPE_RADIO, _("Radio button")),

        (RENDER_TYPE_QUANTITY, _("Quantity boxes")),

    ]

    name = models.CharField(

        max_length=65,

        verbose_name=_("Name"),

    )

    description = models.CharField(

        max_length=255,

        verbose_name=_("Description"),

    )

    limit_per_user = models.PositiveIntegerField(

        null=True,

        blank=True,

        verbose_name=_("Limit per user"),

        help_text=_("The total number of items from this category one "

                    "attendee may purchase."),

    )

    required = models.BooleanField(

        blank=True,

        help_text=_("If enabled, a user must select an "

                    "item from this category."),

    )

    order = models.PositiveIntegerField(

        verbose_name=("Display order"),

    )

    render_type = models.IntegerField(

        choices=CATEGORY_RENDER_TYPES,

        verbose_name=_("Render type"),

        help_text=_("The registration form will render this category in this "

                    "style."),

    )

@python_2_unicode_compatible

class Product(models.Model):

    ''' Registration products '''

    def __str__(self):

        return "%s - %s" % (self.category.name, self.name)

    name = models.CharField(

        max_length=65,

        verbose_name=_("Name"),

    )

    description = models.CharField(

        max_length=255,

        verbose_name=_("Description"),

        null=True,

        blank=True,

    )

    category = models.ForeignKey(

        Category,

        verbose_name=_("Product category")

    )

    price = models.DecimalField(

        max_digits=8,

        decimal_places=2,

        verbose_name=_("Price"),

    )

    limit_per_user = models.PositiveIntegerField(

        null=True,

        blank=True,

        verbose_name=_("Limit per user"),

    )

    reservation_duration = models.DurationField(

        default=datetime.timedelta(hours=1),

        verbose_name=_("Reservation duration"),

        help_text=_("The length of time this product will be reserved before "

                    "it is released for someone else to purchase."),

            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

        last_category = attendee.highest_complete_category

        # Get the next category

        cats = rego.Category.objects

        cats = cats.filter(id__gt=last_category).order_by("order")

        if cats.count() == 0:

            # We've filled in every category

            attendee.completed_registration = True

            attendee.save()

            return next_step

        if last_category == 0:

            # 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"

        for category in cats:

            products = ProductController.available_products(

                request.user,

                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,

            )

            sections.append(section)

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

                if category.id > attendee.highest_complete_category:

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

                    attendee.highest_complete_category = category.id

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

        for section in sections:

            if section.form.errors:

                break

        else:

            attendee.save()

            # 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)

@login_required

def edit_profile(request):

    form, handled = handle_profile(request, "profile")

    data = {

        "form": form,

    }

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

def handle_profile(request, prefix):

    ''' Returns a profile form instance, and a boolean which is true if the

    form was handled. '''

    attendee = rego.Attendee.get_instance(request.user)

    try:

        profile = attendee.attendeeprofilebase

    except ObjectDoesNotExist:

        profile = None

    ProfileForm = get_form(settings.ATTENDEE_PROFILE_FORM)

    # Load a pre-entered name from the speaker's profile,

    # if they have one.

    try:

        speaker_profile = request.user.speaker_profile

        speaker_name = speaker_profile.name

    except ObjectDoesNotExist:

        speaker_name = None

    name_field = ProfileForm.Meta.model.name_field()

    initial = {}

        initial[name_field] = speaker_name

    form = ProfileForm(

        request.POST or None,

        initial=initial,

        instance=profile,

        prefix=prefix

    )

    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):

    ''' Registration selections form for a specific category of items.

    '''

    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 = rego.Category.objects.get(pk=category_id)

    products = ProductController.available_products(

        request.user,

        category=category,

    )

    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

        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 = rego.ProductItem.objects.filter(

        product__in=products,

        cart=current_cart.cart,

    )

    quantities = []

    for product in products:

        # Only add items that are enabled.

        try:

            quantity = items.get(product=product).quantity

        except ObjectDoesNotExist:

            quantity = 0

        quantities.append((product, quantity))

    products_form = ProductsForm(

        request.POST or None,

        product_quantities=quantities,

        prefix=prefix,

    )

    if request.method == "POST" and products_form.is_valid():

        try:

            if products_form.has_changed():

                set_quantities_from_products_form(products_form, current_cart)

        except ValidationError:

            # There were errors, but they've already been added to the form.

            pass

        # If category is required, the user must have at least one

        # in an active+valid cart