import re

import markdown
from django.contrib.auth.models import AbstractUser
from django.contrib.contenttypes.models import ContentType
from django.db import models
from django.template.defaultfilters import slugify
from django.urls import reverse
from django.utils import timezone


class User(AbstractUser):
    pass


class ArticleManager(models.Manager):
    def get_queryset(self):
        return super().get_queryset().filter(page__isnull=True)


class Article(models.Model):
    DRAFT = "draft"
    PUBLISHED = "published"
    STATUS_CHOICES = [
        (DRAFT, "Draft"),
        (PUBLISHED, "Published"),
    ]
    title = models.CharField(max_length=255)
    content = models.TextField()
    status = models.CharField(max_length=15, choices=STATUS_CHOICES, default=DRAFT)
    published_at = models.DateTimeField(null=True, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    author = models.ForeignKey(User, on_delete=models.PROTECT)
    views_count = models.IntegerField(default=0)
    slug = models.SlugField(unique=True)

    objects = ArticleManager()
    with_pages = models.Manager()

    class Meta:
        ordering = ["-published_at"]

    def __str__(self):
        return self.title

    def get_admin_url(self):
        content_type = ContentType.objects.get_for_model(self.__class__)
        return reverse(
            "admin:%s_%s_change" % (content_type.app_label, content_type.model),
            args=(self.id,),
        )

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

    def get_abstract(self):
        html = self.get_formatted_content()
        return html.split("<!--more-->")[0]

    def get_formatted_content(self):
        md = markdown.Markdown(extensions=["extra"])
        content = self.content
        content = re.sub(r"(\s)#(\w+)", r"\1\#\2", content)
        return md.convert(content)

    def publish(self):
        if not self.published_at:
            self.published_at = timezone.now()
        self.status = self.PUBLISHED
        self.save()

    def unpublish(self):
        self.published_at = None
        self.status = self.DRAFT
        self.save()

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


class Page(Article):
    objects = models.Manager()
    position = models.IntegerField(default=0)

    class Meta:
        ordering = ["position", "-published_at"]