models.py

from datetime import timedelta

from django.db import models
from django.db.models import Max, Sum
from django.utils.text import slugify

from inventory.models import AdSlot


# Create your models here.
class Campaign(models.Model):
    book_title = models.CharField(max_length=255)
    date_created = models.DateField(auto_now_add=True)
    date_updated = models.DateField(auto_now=True)
    internal_design = models.BooleanField()
    order = models.ForeignKey('Order')
    start_date = models.DateField()

    @property
    def ad_design_price(self):
        """ Get the sum of all ad design costs in the products for this campaign """
        print(self.product_set.all())
        return self.product_set.all().aggregate(total=Sum('price'))['total']

    @property
    def ad_deadline(self):
        """ Get the distance between the start date and the earliest ad deadline. """
        delta = self.product_set.aggregate(Max('ad_deadline'))['ad_deadline__max']
        return self.start_date - timedelta(days=delta)


class Product(models.Model):
    campaign = models.ForeignKey('Campaign')
    date_created = models.DateField(auto_now_add=True)
    date_updated = models.DateField(auto_now=True)
    product_type = models.ForeignKey('ProductType')
    run_length = models.IntegerField()
    #ad_slot = models.ForeignKey('AdSlot')


class ProductType(models.Model):
    UNKNOWN = 'UNKNOWN'
    WEB = 'WEB'
    PRINT = 'PRINT'
    MOBILE = 'MOBILE'
    EMAIL = 'EMAIL'
    BILLBOARD = 'BILLBOARD'

    MEDIUM_CHOICES = (
        (UNKNOWN, 'Unknown'),
        (WEB, 'Web'),
        (PRINT, 'Print'),
        (EMAIL, 'Email/Newsletter'),
        (BILLBOARD, 'Billboard'),
    )

    RUNLENGTH_CHOICES = (
        ('ISSUES', 'Issues'),
        ('WEEKS', 'Weeks'),
    )

    medium = models.CharField(max_length=50, choices=MEDIUM_CHOICES)
    name = models.CharField(max_length=255, )
    price = models.DecimalField(max_digits=8, decimal_places=2)
    run_length_period = models.CharField(max_length=50, choices=RUNLENGTH_CHOICES)
    slug = models.SlugField(unique=True)
    ad_deadline = models.IntegerField()

    def __str__(self):
        return self.name

    def save(self, **kwargs):
        if not self.slug:
            self.slug = slugify(self.name)
        super().save(**kwargs)

    @property
    def price(self):
        return "${}".format(self.price)


# Three Customer Types
class Customer(models.Model):
    # Add demographic information, payment information
    pass

class Order(models.Model):
    customer = models.ForeignKey('Customer')
    paid = models.BooleanField(default=False)

tests.py

from datetime import datetime, timedelta, date
from django.test import TestCase
from campaigns.models import ProductType, Product, Campaign, Customer, Order

# Create your tests here.
class CampaignTest(TestCase):
    def setUp(self):
        self.customer = Customer.objects.create()
        self.order = Order.objects.create(customer=self.customer, paid=False)
        self.half_page = ProductType.objects.create(
                medium=ProductType.PRINT,
                name='Half Page Ad',
                price='1000',
                run_length_period='ISSUES',
                ad_deadline=21)
        self.campaign = Campaign.objects.create(
                order=self.order,
                book_title='Lies of Locke',
                internal_design=False,
                start_date=date(2016, 5, 1) + timedelta(days=28))
        self.product = Product.objects.create(campaign=self.campaign,
                product_type=self.half_page,
                run_length=14)

    def test_ad_design_price(self):
        self.assertEqual(self.campaign.ad_design_price, 1000)

    def test_ad_deadline(self):
        print(self.campaign.ad_deadline)
        self.assertEqual(self.campaign.ad_deadline, date(2016, 5, 8))

class ProductTypeTest(TestCase):
    def setUp(self):
        self.half_page = ProductType.objects.create(
                medium=ProductType.PRINT,
                name='Half Page Ad',
                price=1000,
                run_length_period='ISSUES',
                ad_deadline=21)

    def test_slug(self):
        self.assertEqual(self.half_page.slug, 'half-page-ad')