from django.db import models
from django.utils import timezone
from django.utils.text import slugify
from django.urls import reverse
from django_ckeditor_5.fields import CKEditor5Field


class Category(models.Model):
    name = models.CharField(max_length=100, unique=True)
    slug = models.SlugField(max_length=100, unique=True, blank=True)
    description = models.TextField(blank=True)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        verbose_name = 'Category'
        verbose_name_plural = 'Categories'
        ordering = ['name']

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

    def __str__(self):
        return self.name


class Tag(models.Model):
    name = models.CharField(max_length=50, unique=True)
    slug = models.SlugField(max_length=50, unique=True, blank=True)

    class Meta:
        ordering = ['name']

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

    def __str__(self):
        return self.name


class Post(models.Model):
    class Status(models.TextChoices):
        DRAFT = 'draft', 'Draft'
        PUBLISHED = 'published', 'Published'

    title = models.CharField(max_length=255)
    slug = models.SlugField(max_length=255, unique=True, blank=True)
    excerpt = models.TextField(max_length=500, help_text="Short description for preview")
    content = models.TextField()
    content = CKEditor5Field('Content', config_name='extends')

    featured_image = models.ImageField(upload_to='blog/images/%Y/%m/', blank=True, null=True)
    
    category = models.ForeignKey(Category, on_delete=models.SET_NULL, null=True, related_name='posts')
    tags = models.ManyToManyField(Tag, blank=True, related_name='posts')
    
    author = models.ForeignKey(
        'users.User',
        on_delete=models.CASCADE,
        related_name='blog_posts'
    )
    
    status = models.CharField(max_length=10, choices=Status.choices, default=Status.DRAFT)
    is_featured = models.BooleanField(default=False)
    
    views_count = models.PositiveIntegerField(default=0)
    
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    published_at = models.DateTimeField(blank=True, null=True)

    class Meta:
        ordering = ['-published_at', '-created_at']
        indexes = [
            models.Index(fields=['-published_at']),
            models.Index(fields=['slug']),
        ]

    def save(self, *args, **kwargs):
        if not self.slug:
            self.slug = slugify(self.title)
        if self.status == self.Status.PUBLISHED and not self.published_at:
            self.published_at = timezone.now()
        super().save(*args, **kwargs)

    def __str__(self):
        return self.title

    def get_absolute_url(self):
        return reverse('blog:post_detail', kwargs={'slug': self.slug})

    @property
    def reading_time(self):
        word_count = len(self.content.split())
        return max(1, word_count // 200)