from django.db import models
from django.utils import timezone
from django.utils.text import slugify


class BlogAuthor(models.Model):
    """Model for blog post authors"""
    name = models.CharField(max_length=200)
    email = models.EmailField(unique=True, blank=True, null=True)
    bio = models.TextField(blank=True)
    avatar = models.ImageField(upload_to='blog/authors/', blank=True, null=True)
    is_active = models.BooleanField(default=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        verbose_name = "Blog Author"
        verbose_name_plural = "Blog Authors"
        ordering = ['name']

    def __str__(self):
        return self.name


class BlogCategory(models.Model):
    """Model for blog post categories"""
    title = models.CharField(max_length=100)
    slug = models.SlugField(max_length=100, unique=True)
    description = models.TextField(blank=True)
    display_order = models.PositiveIntegerField(default=0)
    is_active = models.BooleanField(default=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        verbose_name = "Blog Category"
        verbose_name_plural = "Blog Categories"
        ordering = ['display_order', 'title']

    def __str__(self):
        return self.title

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


class BlogTag(models.Model):
    """Model for blog post tags"""
    name = models.CharField(max_length=50, unique=True)
    slug = models.SlugField(max_length=50, unique=True)
    is_active = models.BooleanField(default=True)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        verbose_name = "Blog Tag"
        verbose_name_plural = "Blog Tags"
        ordering = ['name']

    def __str__(self):
        return self.name

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


class BlogPost(models.Model):
    """Model for blog posts"""
    title = models.CharField(max_length=300)
    slug = models.SlugField(max_length=300, unique=True)
    content = models.TextField()
    excerpt = models.TextField(blank=True, help_text="Short excerpt for preview")
    thumbnail = models.ImageField(upload_to='blog/thumbnails/', blank=True, null=True)
    thumbnail_url = models.CharField(max_length=500, blank=True, help_text="External thumbnail URL")
    featured_image = models.ImageField(upload_to='blog/featured/', blank=True, null=True)
    featured_image_url = models.CharField(max_length=500, blank=True, help_text="External featured image URL")
    
    author = models.ForeignKey(
        BlogAuthor, 
        on_delete=models.SET_NULL, 
        null=True, 
        related_name='posts'
    )
    category = models.ForeignKey(
        BlogCategory, 
        on_delete=models.SET_NULL, 
        null=True, 
        related_name='posts'
    )
    tags = models.ManyToManyField(BlogTag, related_name='posts', blank=True)
    
    # SEO and metadata
    meta_description = models.CharField(max_length=160, blank=True)
    meta_keywords = models.CharField(max_length=255, blank=True)
    
    # Status and visibility
    published = models.BooleanField(default=True)
    featured = models.BooleanField(default=False, help_text="Featured post")
    views_count = models.PositiveIntegerField(default=0)
    reading_time = models.PositiveIntegerField(default=5, help_text="Estimated reading time in minutes")
    
    # Timestamps
    published_at = models.DateTimeField(default=timezone.now)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        verbose_name = "Blog Post"
        verbose_name_plural = "Blog Posts"
        ordering = ['-published_at', '-created_at']
        indexes = [
            models.Index(fields=['-published_at']),
            models.Index(fields=['slug']),
            models.Index(fields=['published']),
        ]

    def __str__(self):
        return self.title

    def save(self, *args, **kwargs):
        if not self.slug:
            self.slug = slugify(self.title)
        if not self.excerpt and self.content:
            # Generate excerpt from content (first 200 characters)
            self.excerpt = self.content[:200] + '...' if len(self.content) > 200 else self.content
        super().save(*args, **kwargs)

    @property
    def get_thumbnail_url(self):
        """Return the thumbnail URL (uploaded image or external URL)"""
        if self.thumbnail and hasattr(self.thumbnail, 'url'):
            return self.thumbnail.url
        elif self.thumbnail_url:
            return self.thumbnail_url
        return None

    @property
    def get_featured_image_url(self):
        """Return the featured image URL (uploaded image or external URL)"""
        if self.featured_image and hasattr(self.featured_image, 'url'):
            return self.featured_image.url
        elif self.featured_image_url:
            return self.featured_image_url
        return None

    def increment_views(self):
        """Increment the view count"""
        self.views_count += 1
        self.save(update_fields=['views_count'])


class BlogComment(models.Model):
    """Model for blog post comments"""
    post = models.ForeignKey(BlogPost, on_delete=models.CASCADE, related_name='comments')
    name = models.CharField(max_length=100)
    email = models.EmailField()
    content = models.TextField()
    parent = models.ForeignKey(
        'self', 
        on_delete=models.CASCADE, 
        null=True, 
        blank=True, 
        related_name='replies'
    )
    is_approved = models.BooleanField(default=False)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        verbose_name = "Blog Comment"
        verbose_name_plural = "Blog Comments"
        ordering = ['-created_at']

    def __str__(self):
        return f"Comment by {self.name} on {self.post.title}"