from django.conf import settings
from django.core.files import File
from django.core.files.base import ContentFile
from django.core.urlresolvers import reverse
from django.db import models
from django.utils import six, timezone
from django.utils.crypto import get_random_string
from PIL import Image


class Attachment(models.Model):
    uuid = models.CharField(max_length=64)
    filetype = models.ForeignKey('AttachmentType')
    post = models.ForeignKey(
        'Post',
        blank=True,
        null=True,
        on_delete=models.SET_NULL
    )

    uploaded_on = models.DateTimeField(default=timezone.now)

    uploader = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        blank=True,
        null=True,
        on_delete=models.SET_NULL
    )
    uploader_name = models.CharField(max_length=255)
    uploader_slug = models.CharField(max_length=255)
    uploader_ip = models.GenericIPAddressField()

    filename = models.CharField(max_length=255)

    thumbnail = models.ImageField(blank=True, null=True, upload_to='attachments')
    image = models.ImageField(blank=True, null=True, upload_to='attachments')
    file = models.FileField(blank=True, null=True, upload_to='attachments')

    downloads = models.PositiveIntegerField(default=0)

    @classmethod
    def generate_new_uuid(cls):
        return get_random_string(settings.MISAGO_ATTACHMENT_SECRET_LENGTH)

    @property
    def is_image(self):
        return bool(self.image)

    @property
    def is_file(self):
        return not self.is_image

    def get_absolute_url(self):
        return reverse('misago:attachment', kwargs={
            'pk': self.pk,
            'uuid': self.uuid,
        })

    def get_thumbnail_url(self):
        if self.is_image:
            return reverse('misago:attachment-thumbnail', kwargs={
                'pk': self.pk,
                'uuid': self.uuid,
            })
        else:
            return None

    def set_file(self, upload):
        file_secret = get_random_string(settings.MISAGO_ATTACHMENT_SECRET_LENGTH)
        self.file = File(upload, '.'.join([file_secret, self.filetype.extensions_list[0]]))

    def set_image(self, upload):
        fileformat = self.filetype.extensions_list[0]

        image_secret = get_random_string(settings.MISAGO_ATTACHMENT_SECRET_LENGTH)
        image_filename = '.'.join([image_secret, fileformat])
        self.image = File(upload, image_filename)

        thumbnail = Image.open(upload)
        thumbnail.thumbnail((500, 500))

        if six.PY3:
            thumb_stream = six.StringIO()
        else:
            thumb_stream = six.BytesIO()
        thumbnail.save(thumb_stream, fileformat)

        thumb_secret = get_random_string(settings.MISAGO_ATTACHMENT_SECRET_LENGTH)
        thumb_filename = '.'.join([thumb_secret, fileformat])
        self.thumbnail = ContentFile(thumb_stream, thumb_filename)