from django.conf import settings
from django.db import models
from django.db.models.aggregates import Sum
from django.contrib import messages
from django.contrib.postgres.fields import DateTimeRangeField, JSONField
from django.http import HttpResponse
from django.utils.text import slugify
from django.utils.translation import ugettext_lazy as _
from django.utils import timezone
from django.core.urlresolvers import reverse_lazy
from utils.models import UUIDModel, CreatedUpdatedModel
from .managers import ProductQuerySet, OrderQuerySet
import hashlib, io, base64, qrcode
from decimal import Decimal
from datetime import timedelta


class Order(CreatedUpdatedModel):

    class Meta:
        unique_together = ('user', 'open')
        ordering = ['-created']

    products = models.ManyToManyField(
        'shop.Product',
        through='shop.OrderProductRelation'
    )

    user = models.ForeignKey(
        'auth.User',
        verbose_name=_('User'),
        help_text=_('The user this order belongs to.'),
        related_name='orders',
    )

    paid = models.BooleanField(
        verbose_name=_('Paid?'),
        help_text=_('Whether this order has been paid.'),
        default=False,
    )

    open = models.NullBooleanField(
        verbose_name=_('Open?'),
        help_text=_('Whether this order is open or not. "None" means closed.'),
        default=True,
    )

    camp = models.ForeignKey(
        'camps.Camp',
        verbose_name=_('Camp'),
        help_text=_('The camp this order is for.'),
    )

    CREDIT_CARD = 'credit_card'
    BLOCKCHAIN = 'blockchain'
    BANK_TRANSFER = 'bank_transfer'

    PAYMENT_METHODS = [
        CREDIT_CARD,
        BLOCKCHAIN,
        BANK_TRANSFER,
    ]

    PAYMENT_METHOD_CHOICES = [
        (CREDIT_CARD, 'Credit card'),
        (BLOCKCHAIN, 'Blockchain'),
        (BANK_TRANSFER, 'Bank transfer'),
    ]

    payment_method = models.CharField(
        max_length=50,
        choices=PAYMENT_METHOD_CHOICES,
        default='',
    )

    cancelled = models.BooleanField(default=False)

    refunded = models.BooleanField(
        verbose_name=_('Refunded?'),
        help_text=_('Whether this order has been refunded.'),
        default=False,
    )

    objects = OrderQuerySet.as_manager()

    def __str__(self):
        return 'order id #%s' % self.pk

    def get_number_of_items(self):
        return self.products.aggregate(
            sum=Sum('orderproductrelation__quantity')
        )['sum']

    @property
    def vat(self):
        return Decimal(self.total*Decimal(0.2))

    @property
    def total(self):
        if self.products.all():
            return Decimal(self.products.aggregate(
                sum=Sum(
                    models.F('orderproductrelation__product__price') *
                    models.F('orderproductrelation__quantity'),
                    output_field=models.IntegerField()
                )
            )['sum'])
        else:
            return False

    def get_coinify_callback_url(self, request):
        return 'https://' + request.get_host() + str(reverse_lazy('shop:coinify_callback', kwargs={'pk': self.pk}))

    def get_coinify_thanks_url(self, request):
        return 'https://' + request.get_host() + str(reverse_lazy('shop:coinify_thanks', kwargs={'pk': self.pk}))

    def get_epay_accept_url(self, request):
        return 'https://' + request.get_host() + str(reverse_lazy('shop:epay_thanks', kwargs={'pk': self.pk}))

    def get_cancel_url(self, request):
        return 'https://' + request.get_host() + str(reverse_lazy('shop:order_detail', kwargs={'pk': self.pk}))

    def get_epay_callback_url(self, request):
        return 'https://' + request.get_host() + str(reverse_lazy('shop:epay_callback', kwargs={'pk': self.pk}))

    @property
    def description(self):
        return "BornHack %s order #%s" % (self.camp.start.year, self.pk)

    def get_absolute_url(self):
        return str(reverse_lazy('shop:order_detail', kwargs={'pk': self.pk}))

    def mark_as_paid(self):
        self.paid = True
        self.open = None
        for order_product in self.orderproductrelation_set.all():
            category_pk = str(order_product.product.category.pk)
            if category_pk == settings.TICKET_CATEGORY_ID:
                for _ in range(0, order_product.quantity):
                    ticket = Ticket(
                        order=self,
                        product=order_product.product,
                    )
                    ticket.save()
        self.save()

    def mark_as_refunded(self, request):
        if not self.paid:
            messages.error(request, "Order %s is not paid, so cannot mark it as refunded!" % self.pk)
        else:
            self.refunded=True
            ### delete any tickets related to this order
            if self.tickets.all():
                messages.success(request, "Order %s marked as refunded, deleting %s tickets..." % (self.pk, self.tickets.count()))
                self.tickets.all().delete()
            else:
                messages.success(request, "Order %s marked as refunded, no tickets to delete" % self.pk)
            self.save()

    def is_not_handed_out(self):
        if self.orderproductrelation_set.filter(handed_out=True).count() == 0:
            return True
        else:
            return False

    def is_partially_handed_out(self):
        if self.orderproductrelation_set.filter(handed_out=True).count() != 0 and self.orderproductrelation_set.filter(handed_out=False).count() != 0:
            # some products are handed out, others are not
            return True
        else:
            return False

    def is_fully_handed_out(self):
        if self.orderproductrelation_set.filter(handed_out=False).count() == 0:
            return True
        else:
            return False

    @property
    def handed_out_status(self):
        if self.is_not_handed_out():
            return "no"
        elif self.is_partially_handed_out():
            return "partially"
        elif self.is_fully_handed_out():
            return "fully"
        else:
            return False

    def mark_as_cancelled(self):
        self.cancelled = True
        self.open = None
        self.save()


class ProductCategory(CreatedUpdatedModel, UUIDModel):
    class Meta:
        verbose_name = 'Product category'
        verbose_name_plural = 'Product categories'

    name = models.CharField(max_length=150)
    slug = models.SlugField()
    public = models.BooleanField(default=True)

    def __str__(self):
        return self.name

    def save(self, **kwargs):
        self.slug = slugify(self.name)
        super(ProductCategory, self).save(**kwargs)


class Product(CreatedUpdatedModel, UUIDModel):
    class Meta:
        verbose_name = 'Product'
        verbose_name_plural = 'Products'
        ordering = ['available_in', 'price']

    category = models.ForeignKey(
        'shop.ProductCategory',
        related_name='products'
    )

    name = models.CharField(max_length=150)
    slug = models.SlugField()

    price = models.IntegerField(
        help_text=_('Price of the product (in DKK).')
    )

    description = models.TextField()

    available_in = DateTimeRangeField(
        help_text=_(
            'Which period is this product available for purchase? | '
            '(Format: YYYY-MM-DD HH:MM) | Only one of start/end is required'
        )
    )
    
    objects = ProductQuerySet.as_manager()

    def __str__(self):
        return '{} ({} DKK)'.format(
            self.name,
            self.price,
        )

    def is_available(self):
        now = timezone.now()
        return now in self.available_in


class OrderProductRelation(CreatedUpdatedModel):
    order = models.ForeignKey('shop.Order')
    product = models.ForeignKey('shop.Product')
    quantity = models.PositiveIntegerField()
    handed_out = models.BooleanField(default=False)

    @property
    def total(self):
        return Decimal(self.product.price * self.quantity)


class EpayCallback(CreatedUpdatedModel, UUIDModel):
    class Meta:
        verbose_name = 'Epay Callback'
        verbose_name_plural = 'Epay Callbacks'
        ordering = ['-created']

    payload = JSONField()
    md5valid = models.BooleanField(default=False)

    def __str__(self):
        return 'callback at %s (md5 valid: %s)' % (self.created, self.md5valid)


class EpayPayment(CreatedUpdatedModel, UUIDModel):
    class Meta:
        verbose_name = 'Epay Payment'
        verbose_name_plural = 'Epay Payments'

    order = models.OneToOneField('shop.Order')
    callback = models.ForeignKey('shop.EpayCallback')
    txnid = models.IntegerField()


class CreditNote(CreatedUpdatedModel):
    class Meta:
        ordering = ['-created']

    amount = models.DecimalField(max_digits=10, decimal_places=2)
    text = models.TextField()
    pdf = models.FileField(
        null=True,
        blank=True,
        upload_to='creditnotes/'
    )
    user = models.ForeignKey(
        'auth.User',
        verbose_name=_('User'),
        help_text=_('The user this credit note belongs to.'),
        related_name='creditnotes',
    )
    paid = models.BooleanField(
        verbose_name=_('Paid?'),
        help_text=_('Whether the amount in this creditnote has been paid back to the customer.'),
        default=False,
    )
    sent_to_customer = models.BooleanField(default=False)

    def __str__(self):
        return 'creditnote#%s - %s DKK (sent to %s: %s)' % (
            self.id,
            self.amount,
            self.user.email,
            self.sent_to_customer,
        )

    @property
    def vat(self):
        return Decimal(self.amount*Decimal(0.2))

    @property
    def filename(self):
        return 'bornhack_creditnote_%s.pdf' % self.pk


class Invoice(CreatedUpdatedModel):
    order = models.OneToOneField('shop.Order')
    pdf = models.FileField(null=True, blank=True, upload_to='invoices/')
    sent_to_customer = models.BooleanField(default=False)

    def __str__(self):
        return 'invoice#%s - order %s - %s - total %s DKK (sent to %s: %s)' % (
            self.id,
            self.order.id,
            self.order.created,
            self.order.total,
            self.order.user.email,
            self.sent_to_customer,
        )

    @property
    def filename(self):
        return 'bornhack_invoice_%s.pdf' % self.pk

    def regretdate(self):
        return self.created+timedelta(days=15)


class CoinifyAPIInvoice(CreatedUpdatedModel):
    invoicejson = JSONField()
    order = models.OneToOneField('shop.Order')

    def __str__(self):
        return "coinifyinvoice for order #%s" % self.order.id


class CoinifyAPICallback(CreatedUpdatedModel):
    headers = JSONField()
    payload = JSONField()
    order = models.ForeignKey('shop.Order')
    valid = models.BooleanField(default=False)

    def __str__(self):
        return 'order #%s callback at %s' % (self.order.id, self.created)


class Ticket(CreatedUpdatedModel, UUIDModel):
    order = models.ForeignKey('shop.Order', related_name='tickets')
    product = models.ForeignKey('shop.Product', related_name='tickets')
    qrcode_base64 = models.TextField(null=True, blank=True)

    name = models.CharField(
        max_length=100,
        help_text=(
            'Name of the person this ticket belongs to. '
            'This can be different from the buying user.'
        ),
        null=True,
        blank=True,
    )

    email = models.EmailField(
        null=True,
        blank=True,
    )

    def __str__(self):
        return 'Ticket {user} {product}'.format(
            user=self.order.user,
            product=self.product
        )

    def save(self, **kwargs):
        super(Ticket, self).save(**kwargs)
        self.qrcode_base64 = self.get_qr_code()
        super(Ticket, self).save(**kwargs)

    def get_token(self):
        return hashlib.sha256(
            '{ticket_id}{user_id}{secret_key}'.format(
                ticket_id=self.pk,
                user_id=self.order.user.pk,
                secret_key=settings.SECRET_KEY,
            )
        ).hexdigest()

    def get_qr_code(self):
        qr = qrcode.make(
            self.get_token(),
            version=1,
            error_correction=qrcode.constants.ERROR_CORRECT_H
        ).resize((250,250))
        file_like = io.BytesIO()
        qr.save(file_like, format='png')
        qrcode_base64 = base64.b64encode(file_like.getvalue())
        return qrcode_base64

    def get_qr_code_url(self):
        return 'data:image/png;base64,{}'.format(self.qrcode_base64)

    def get_absolute_url(self):
        return str(reverse_lazy('shop:ticket_detail', kwargs={'pk': self.pk}))