expephalon/core/models/billable.py

from django.db.models import IntegerChoices, Model, ForeignKey, CASCADE, TextField, PositiveIntegerField, BooleanField, DateField
from django.utils import timezone

from core.models.profiles import ClientProfile
from core.models.brands import Brand
from core.fields.base import LongCharField
from core.fields.numbers import CostField
from core.models.invoices import InvoiceItem, Invoice

from dateutil.relativedelta import relativedelta


class ActionChoices(IntegerChoices):
    WAIT = 0, "Do not invoice for now"
    NEXT = 1, "Add to client's next invoice"
    CRON = 2, "Invoice at next cron run"
    DATE = 3, "Invoice at date"


class CycleChoices(IntegerChoices):
    DAYS = 0, "Days"
    WEEKS = 1, "Weeks"
    MONTHS = 2, "Months"
    YEARS = 3, "Years"


class Billable(Model):
    client = ForeignKey(ClientProfile, on_delete=CASCADE)
    brand = ForeignKey(Brand, on_delete=CASCADE)
    name = LongCharField()
    description = TextField()
    individual_cost = CostField()
    amount = PositiveIntegerField()
    taxable = BooleanField()
    action = PositiveIntegerField(choices=ActionChoices.choices)
    date = DateField(null=True)
    recur_cycle = PositiveIntegerField(choices=CycleChoices.choices, null=True)
    recur_count = PositiveIntegerField(null=True)

    def next_invoicing(self):
        try:
            invoiceitems = InvoiceItem.objects.filter(billable=self)

            if not recur_cycle:
                return False

            invoice = Invoice.objects.filter(invoiceitem_set__contains=invoiceitems).latest("created")
            delta = relativedelta(days=self.recur_count if self.recur_cycle == CycleChoices.DAYS else 0, 
                                  weeks=self.recur_count if self.recur_cycle == CycleChoices.WEEKS else 0,
                                  months=self.recur_count if self.recur_cycle == CycleChoices.MONTHS else 0, 
                                  years=self.recur_count if self.recur_cycle == CycleChoices.YEARS else 0)

            return invoice.created + delta

        except:
            return self.date