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


class Comment(models.Model):
    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
    object_id = models.CharField(max_length=255, db_index=True)
    content_object = GenericForeignKey("content_type", "object_id")

    author = models.ForeignKey(
        settings.AUTH_USER_MODEL, null=True, blank=True, on_delete=models.SET_NULL, related_name="comments"
    )
    parent = models.ForeignKey(
        "self", null=True, blank=True, on_delete=models.CASCADE, related_name="replies"
    )
    mentions = models.ManyToManyField(
        settings.AUTH_USER_MODEL, blank=True, related_name="mentioned_comments"
    )
    attachments = models.ManyToManyField(
        "attachments.Attachment", blank=True, related_name="comments"
    )
    body = models.TextField(blank=True, default="")
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        db_table = "comments"
        ordering = ["created_at"]
        indexes = [
            models.Index(fields=["content_type", "object_id", "-created_at", "-id"], name="comment_obj_time_idx"),
        ]

    def __str__(self):
        return f"Comment by {self.author or 'deleted user'} on {self.content_type}"