from django.db import models

from imagekit.models import ImageSpecField
from imagekit.processors import ResizeToFill
from django.utils.translation import ugettext_lazy as _
from django.contrib.auth import get_user_model

def user_directory_path(instance, filename):
    # file will be uploaded to MEDIA_ROOT/photos/<login>/<filename>
    return 'photos/{0}/{1}'.format(instance.user.username, filename)

class TimestampMixin(models.Model):
    created_at = models.DateTimeField(_("Created at"), auto_now_add=True)
    updated_at = models.DateTimeField(_("Updated at"), auto_now=True)

    class Meta:
        abstract = True

class UserMixin(models.Model):
    user = models.ForeignKey(get_user_model(), on_delete=models.CASCADE, null=True, verbose_name=_("User"))

    def is_owned_by(self, user):
        return self.user is not None and user is not None and self.user.id == user.id

    class Meta:
        abstract = True

class Album(TimestampMixin, UserMixin):
    title = models.CharField(_("Title"), max_length=255)
    description = models.TextField(_("Description"), null=True, blank=True)
    
    def __str__(self):
        return self.title

    class Meta:
        verbose_name = _('album')
        verbose_name_plural = _('albums')

class Photo(TimestampMixin, UserMixin):
    photo = models.ImageField(_("Photo"), upload_to=user_directory_path)
    thumbnail = ImageSpecField(
        source='photo', 
        format='JPEG', 
        options={'quality': 80}, 
        processors=[ResizeToFill(300, 200, upscale=False)])

    title = models.CharField(_("Title"), max_length=255)
    
    # some optional data
    description = models.TextField(_("Description"), null=True, blank=True)
    taken_on = models.DateField(_("Taken on"), null=True, blank=True)

    album = models.ForeignKey(Album, on_delete=models.CASCADE, null=True)
    
    class Meta:
        verbose_name = _('photo')
        verbose_name_plural = _('photos')