import os
from PIL import Image
from django.db import models
from django.db.models.signals import post_save
from django.contrib.sitemaps import Sitemap
from django.dispatch import receiver
from django.urls import reverse
from django.apps import apps
from django.utils.html import format_html
from django.conf import settings

from media.utils import resize_image
from utils.util import markdown_to_html


def get_upload_path(self, filename):
    return "wandrenbooks.net/media/images/book-covers/%s" % (filename)


class Book(models.Model):
    title = models.CharField(max_length=200)
    author_last_name = models.CharField(max_length=200)
    author_first_name = models.CharField(max_length=200)
    slug = models.CharField(max_length=50)
    isbn = models.CharField(max_length=100, blank=True, null=True)
    body_markdown = models.TextField(blank=True)
    body_html = models.TextField(null=True, blank=True)
    pages = models.CharField(max_length=5, blank=True, null=True)
    amazon_link = models.CharField(max_length=400, blank=True, null=True)
    bookshop_link = models.CharField(max_length=400, blank=True, null=True)
    thriftbooks_link = models.CharField(max_length=400, blank=True, null=True)
    other_link = models.CharField(max_length=400, blank=True, null=True)
    image = models.FileField(upload_to=get_upload_path, null=True, blank=True)

    def __str__(self):
        return self.title

    def get_absolute_url(self):
        return reverse("books:detail", kwargs={"slug": self.slug})

    def get_image_url(self):
        return '%sbook-covers/%s' % (settings.IMAGES_URL, self.image.name.split('/')[-1])

    def get_small_image_url(self):
        filename, file_extension = os.path.splitext(self.image.path)
        return "%s/book-covers/%s_small%s" % (settings.IMAGES_URL, filename.split('/')[-1], file_extension)

    @property
    def get_previous_admin_url(self):
        n = self.get_previous_by_read_date()
        return reverse('admin:%s_%s_change' % (self._meta.app_label,  self._meta.model_name),  args=[n.id])

    @property
    def get_next_admin_url(self):
        model = apps.get_model(app_label=self._meta.app_label, model_name=self._meta.model_name)
        try:
            return reverse('admin:%s_%s_change' % (self._meta.app_label,  self._meta.model_name),  args=[self.get_next_by_read_date().pk])
        except model.DoesNotExist:
            return ''

    def admin_thumbnail(self):
        return format_html('<img src="%s" width="100" style="width:100px" />' % (self.get_image_url()))
    admin_thumbnail.short_description = 'Thumbnail'

    def save(self, *args, **kwargs):
        if self.body_markdown:
            self.body_html = markdown_to_html(self.body_markdown)
        super(Book, self).save()


@receiver(post_save, sender=Book)
def post_save_events(sender, update_fields, created, instance, **kwargs):
    if instance.image:
        base_path = "%s/%s/" % (settings.IMAGES_ROOT, "/".join(str(i) for i in instance.image.name.split('/')[3:-1]))
        filename, file_extension = os.path.splitext(instance.image.path)
        img = Image.open(instance.image.path)
        resize_image(img, None, 160, 78, base_path, "%s_tn%s" % (filename.split('/')[-1], file_extension))
        resize_image(img, None, 600, 78, base_path, "%s_small%s" % (filename.split('/')[-1], file_extension))


class BookSitemap(Sitemap):
    changefreq = "never"
    priority = 0.7
    protocol = "https"

    def items(self):
        return Book.objects.filter(is_public=True).exclude(body_markdown='')

    def lastmod(self, obj):
        return obj.read_date