from math import fsum

from django.db import models
from django.db.models.signals import pre_save, post_save
from django.dispatch import receiver

from billing.models import BillingProfile
from carts.models import Cart
from ecommerce.utils import unique_order_id_generator
from addresses.models import Address

ORDER_STATUS_CHOICES = (
    ('created', 'Created'),
    ('paid', 'Paid'),
    ('shipped', 'Shipped'),
    ('refunded', 'Refunded')
)


class OrderManager(models.Manager):
    def new_or_get(self, billing_profile, cart_obj):
        created = False
        qs = self.get_queryset().filter(billing_profile=billing_profile,
                                        cart=cart_obj, active=True,
                                        status='created')
        if qs.count() == 1:
            obj = qs.first()
        else:
            obj = self.model.objects.create(billing_profile=billing_profile,
                                                  cart=cart_obj)
            created = True
        return obj, created

class Order(models.Model):
    billing_profile = models.ForeignKey(BillingProfile, null=True, blank=True)
    order_id = models.CharField(max_length=100, blank=True)
    address = models.ForeignKey(Address, null=True, blank=True)
    cart = models.ForeignKey(Cart)
    status = models.CharField(max_length=120, default='created', choices=ORDER_STATUS_CHOICES)
    shipping_total = models.DecimalField(default=5.99, max_digits=100, decimal_places=2)
    total = models.DecimalField(default=0.00, max_digits=100, decimal_places=2)
    active = models.BooleanField(default=True)

    objects = OrderManager()

    def __str__(self):
        return self.order_id

    def update_total(self):
        cart_total = self.cart.total
        shipping_total = self.shipping_total
        total = fsum([cart_total, shipping_total])
        total = format(total, '.2f')
        self.total = total
        self.save()
        return total

    def check_done(self):
        billing_profile = self.billing_profile
        address = self.address
        total = self.total
        if billing_profile and address and total > 0:
            return True
        return False

    def mark_paid(self):
        if self.check_done():
            self.status = "paid"
            self.save()
        return self.status




@receiver(pre_save, sender=Order)
def create_order_id(sender, instance, *args, **kwargs):
    print('ord_id')
    if not instance.order_id:
        instance.order_id = unique_order_id_generator(instance)
    qs = Order.objects.filter(cart=instance.cart).exclude(billing_profile=instance.billing_profile)
    if qs.exists():
        qs.update(active=False)


@receiver(post_save, sender=Cart)
def create_cart_total(sender, instance, created, *args, **kwargs):
    if not created:
        cart_obj = instance
        cart_total = cart_obj.total
        cart_id = cart_obj.id
        qs = Order.objects.filter(cart__id=cart_id)
        if qs.count() == 1:
            order_obj = qs.first()
            order_obj.update_total()


@receiver(post_save, sender=Order)
def create_order(sender, instance, created, *args, **kwargs):
    if created:
        instance.update_total()