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


class BaseModel(models.Model):
    """基础模型，包含通用时间字段"""
    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


# ─── 软删除（停用 = 逻辑删除）────────────────────────────────────────────────────

class SoftDeleteQuerySet(models.QuerySet):
    """QuerySet.delete() 改为逻辑删除；hard_delete() 才物理删除。"""

    def delete(self):
        return self.update(is_deleted=True, deleted_at=timezone.now())

    def hard_delete(self):
        return super().delete()

    def alive(self):
        return self.filter(is_deleted=False)


class SoftDeleteManager(models.Manager):
    """默认只返回未删除的数据。"""

    def get_queryset(self):
        return SoftDeleteQuerySet(self.model, using=self._db).filter(is_deleted=False)


class AllObjectsManager(models.Manager):
    """包含已删除数据（管理/恢复用）。"""

    def get_queryset(self):
        return SoftDeleteQuerySet(self.model, using=self._db)


class SoftDeleteModel(BaseModel):
    """软删除基类：停用/下架一律逻辑删除，绝不物理删除。

    - `objects`：默认管理器，只含未删除数据。
    - `all_objects`：含已删除数据。
    - 实例 `.delete()` → 逻辑删除；`.hard_delete()` → 物理删除。
    """
    is_deleted = models.BooleanField('是否删除', default=False, db_index=True)
    deleted_at = models.DateTimeField('删除时间', null=True, blank=True)

    objects = SoftDeleteManager()
    all_objects = AllObjectsManager()

    class Meta:
        abstract = True

    def delete(self, using=None, keep_parents=False):
        self.is_deleted = True
        self.deleted_at = timezone.now()
        self.save(using=using, update_fields=['is_deleted', 'deleted_at', 'updated_at'])

    def hard_delete(self, using=None, keep_parents=False):
        super().delete(using=using, keep_parents=keep_parents)

    def restore(self, using=None):
        self.is_deleted = False
        self.deleted_at = None
        self.save(using=using, update_fields=['is_deleted', 'deleted_at', 'updated_at'])