from django.db import models
from django.conf import settings
from django.contrib.contenttypes.fields import GenericForeignKey
from django.contrib.contenttypes.models import ContentType

class CommentThread(models.Model):
    """
    A generic comment thread that can be attached to any model instance.
    Used for tracking discussions on various objects across the platform.
    """
    content_type = models.ForeignKey(
        ContentType,
        on_delete=models.CASCADE,
        related_name='comment_threads'
    )
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')

    title = models.CharField(max_length=255, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    created_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.SET_NULL,
        null=True,
        related_name='created_comment_threads'
    )
    is_locked = models.BooleanField(default=False)
    is_hidden = models.BooleanField(default=False)

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

    def __str__(self):
        return f"Comment Thread on {self.content_object} - {self.title}"


class Comment(models.Model):
    """
    Individual comment within a comment thread.
    """
    thread = models.ForeignKey(
        CommentThread,
        on_delete=models.CASCADE,
        related_name='comments'
    )
    author = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.SET_NULL,
        null=True,
        related_name='comments'
    )
    content = models.TextField()
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    is_edited = models.BooleanField(default=False)
    is_hidden = models.BooleanField(default=False)
    parent = models.ForeignKey(
        'self',
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name='replies'
    )

    class Meta:
        ordering = ['created_at']

    def __str__(self):
        return f"Comment by {self.author} on {self.created_at}"