from datetime import datetime

from django.db import models
from store.models import ProductVariation


def get_change(current, previous):
    if current == previous:
        return 100.0
    try:
        return (abs(current - previous) / previous) * 100.0
    except ZeroDivisionError:
        return 0


class DTYSModel(models.Model):
    """Drop `Til You Shop Model"""

    product = models.ForeignKey(ProductVariation)

    price_start = models.IntegerField()
    price_end = models.IntegerField()
    price_stopped = models.IntegerField(default=0)

    start_date = models.DateField()
    start_time = models.TimeField()

    end_date = models.DateField()
    end_time = models.TimeField()

    is_stopped = models.BooleanField(default=False)
    is_public = models.BooleanField(default=False)

    @property
    def end_datetime(self):
        return datetime.combine(self.end_date, self.end_time)

    @property
    def start_datetime(self):
        return datetime.combine(self.start_date, self.start_time)

    def get_dec_by_sec(self):
        return "%.1f" % (self.get_price_diff() / self.get_date_delta())

    def get_price_diff(self):
        return self.price_start - self.price_end

    def _time_percent(self):
        time_percent = get_change(
            self.get_delta_now(),
            self.get_date_delta()
        )
        return time_percent

    def get_delta_now(self):
        """in seconds"""
        from django.utils import timezone as tz
        _now = tz.now()
        return (self.end_datetime - _now).total_seconds()

    def get_date_delta(self):
        """ in seconds """
        return (self.end_datetime - self.start_datetime).total_seconds()

    def get_current_price(self):
        dec_from_price = (self.get_price_diff() * (self._time_percent() / 100))
        price_current = self.price_start - dec_from_price

        return price_current

    def current_price_format(self):
        return "%.1f" % self.get_current_price()

    def stop(self):
        """Stop this DTYS"""
        self.is_stopped = True

        if not self.price_stopped:
            self.price_stopped = max(self.price_end, self.get_current_price())

        self.save()