from datetime import datetime
from math import floor

from django.core.exceptions import ValidationError
from django.db import models
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")

    @property
    def photos_in_album(self):
        return self.photos.count()

    @property
    def photos_views(self):
        total_views = sum(self.photos.views())
        return total_views

    @property
    def cover_image_data(self):
        def compute_size(photo, max_w=720, max_h=720):
            if not photo.width or not photo.height:
                return (None, None)
            aspect = photo.aspect_ratio
            if photo.width > photo.height:
                w = min(photo.width, max_w)
                h = floor(w / aspect)
            else:
                h = min(photo.height, max_h)
                w = floor(h * aspect)
            return (w, h)

        photo = self.cover or self.photos.order_by('-width').first()
        if photo:
            url = photo.photo_md.url
            w, h = compute_size(photo)
            return {
                "url": url,
                "width": w,
                "height": h,
                "aspect_ratio": round(photo.aspect_ratio, 3)
            }

        return {
            "url": static('img/placeholder.png'),
            "width": 1200,
            "height": 800,
            "aspect_ratio": 1.5
        }


    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)