from django.db import models
from .district import District
from django.utils import timezone

class Device(models.Model):
    address = models.CharField(max_length=100, unique=True)
    district = models.ForeignKey(District, on_delete=models.PROTECT)
    due_date = models.DateField(null=True, blank=True)
    amount = models.IntegerField(null=True, blank=True)
    is_paid = models.BooleanField(default=False)
    created_at = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.address

    @property
    def days_until_due(self):
        """Calculate days remaining until payment is due"""
        if not self.due_date:
            return None
        today = timezone.now().date()
        delta = self.due_date - today
        return delta.days

    @property
    def is_overdue(self):
        """Check if payment is overdue"""
        if not self.due_date or self.is_paid:
            return False
        today = timezone.now().date()
        return self.due_date < today