from django.db import models
from django.db.models.signals import pre_delete
from django.dispatch import receiver
from django.conf import settings
from django.contrib.auth.models import User


class Tag(models.Model):
    """태그 모델"""
    name = models.CharField(max_length=50, unique=True)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ['name']

    def __str__(self):
        return self.name


class Post(models.Model):
    title = models.CharField(max_length=255)
    content = models.TextField()
    tags = models.ManyToManyField(Tag, related_name='posts', blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    author_id = models.CharField(max_length=150, blank=True, default='')
    author_name = models.CharField(max_length=150)
    is_private = models.BooleanField(default=False)  # 비공개 여부 (True: 작성자만 볼 수 있음)

    class Meta:
        ordering = ['-created_at']

    def __str__(self):
        return self.title


class Comment(models.Model):
    """댓글/대댓글 모델"""
    post = models.ForeignKey(
        Post,
        related_name="comments",
        on_delete=models.CASCADE
    )
    parent = models.ForeignKey(
        'self',
        null=True,
        blank=True,
        related_name="replies",
        on_delete=models.CASCADE
    )  # 대댓글 지원
    content = models.TextField()
    author_id = models.CharField(max_length=150, blank=True, default='')
    author_name = models.CharField(max_length=150)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ['created_at']

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


class Attachment(models.Model):
    """첨부파일 모델"""
    post = models.ForeignKey(
        Post,
        related_name="attachments",
        on_delete=models.CASCADE,
        null=True,
        blank=True
    )  # null이면 임시 파일 (아직 게시글에 연결되지 않음)
    file = models.FileField(upload_to='attachments/%Y/%m/%d/')
    original_name = models.CharField(max_length=255)  # 원본 파일명
    file_size = models.PositiveIntegerField()  # 파일 크기 (bytes)
    uploaded_at = models.DateTimeField(auto_now_add=True)
    uploader_id = models.CharField(max_length=150, blank=True, default='')  # 업로더 ID
    uploader_name = models.CharField(max_length=150, blank=True, default='')  # 업로더 이름
    batch_id = models.CharField(max_length=36, blank=True, default='')  # 업로드 배치 ID (같은 게시글 그룹)

    def __str__(self):
        return self.original_name


@receiver(pre_delete, sender=Attachment)
def delete_attachment_file(sender, instance, **kwargs):
    """Attachment 삭제 시 MinIO에서 파일도 삭제"""
    if instance.file:
        instance.file.delete(save=False)