from datetime import datetime
from math import floor

from django.core.cache import cache
from django.core.exceptions import ValidationError
from django.db import models
from django.db.models import Sum
from django.db.models.signals import post_save
from django.dispatch import receiver
from django.templatetags.static import static
from django.urls import reverse
from django.utils.text import slugify

from gallery.models.location import Location


class Album(models.Model):
    name = models.CharField(max_length=150, unique=True, verbose_name="Album")
    slug = models.SlugField(max_length=150, unique=True, verbose_name="Slug")
    location = models.ForeignKey(Location, blank=True, null=True, on_delete=models.SET_NULL, related_name='albums', verbose_name="Location")
    album_date = models.DateField(default=datetime.now, verbose_name="Album Date")
    cover = models.ForeignKey("Photo", blank=True, null=True, on_delete=models.SET_NULL, related_name='cover_to', verbose_name="Album cover")
    is_public = models.BooleanField(default=False, verbose_name="Published")

    def _cache_key(self, suffix):
        return f'album_{self.pk}_{suffix}'

    @property
    def photos_in_album(self):
        key = self._cache_key('photo_count')
        count = cache.get(key)

        if count is None:
            count = self.photos.count()
            cache.set(key, count, 60 * 60 * 24)  # Cache 24 h

        return count

    @property
    def photos_views(self):
        key = self._cache_key('photo_views')
        views = cache.get(key)

        if views is None:
            views = self.photos.aggregate(total_views=Sum('views'))['total_views'] or 0
            cache.set(key, views, 60 * 5)  # Cache 5 min

        return views

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

    def get_absolute_url(self):
        return reverse('gallery:album_url', kwargs={'album_slug': self.slug})

    class Meta:
        verbose_name_plural = "Albums"
        ordering = ('album_date',)

    def __str__(self):
        return '{}'.format(self.name)


@receiver(post_save, sender=Album)
def delete_album_cover_cache(sender, instance, **kwargs):
    cache.delete(f'cover_image_data_{instance.pk}')