"""跨业务应用复用的抽象模型。"""

from django.conf import settings
from django.db import models


class TimeStampedModel(models.Model):
    """统一维护创建和更新时间，避免各业务模型重复声明。"""

    created_at = models.DateTimeField("创建时间", auto_now_add=True)
    updated_at = models.DateTimeField("更新时间", auto_now=True)

    class Meta:
        abstract = True


class UserOwnedModel(TimeStampedModel):
    """为用户私有数据提供显式归属；审计数据存在时禁止删除用户。"""

    owner = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.PROTECT,
        related_name="%(app_label)s_%(class)s_items",
        verbose_name="所属用户",
    )

    class Meta:
        abstract = True