"""租户范围模型的抽象基类。

所有业务表都应该继承 TenantScopedModel，自动获得：
- tenant_id 外键
- org_id 外键（可选，预留多组织）
- 标准审计字段（created_at, updated_at, created_by, updated_by, is_deleted）
- manager `for_tenant(tenant)` 自动加过滤
"""

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


class TenantScopedQuerySet(models.QuerySet):
    def for_tenant(self, tenant):
        return self.filter(tenant=tenant)

    def for_org(self, org):
        return self.filter(org=org)

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


class TenantScopedModel(models.Model):
    tenant = models.ForeignKey(
        "core.Tenant",
        on_delete=models.PROTECT,
        related_name="+",
        help_text="所属租户",
    )
    org = models.ForeignKey(
        "core.Org",
        null=True,
        blank=True,
        on_delete=models.PROTECT,
        related_name="+",
        help_text="所属组织（多机构预留）",
    )

    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    created_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="+",
    )
    updated_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="+",
    )

    # 软删除预留
    is_deleted = models.BooleanField(default=False)
    deleted_at = models.DateTimeField(null=True, blank=True)

    # 扩展 JSON 字段：存自定义属性/第三方对接数据/AI 抽取结果
    ext_data = models.JSONField(default=dict, blank=True)

    # 来源渠道（预留 AI Agent / 电商对接）：manual/api/web/miniprogram/ai_agent
    source_channel = models.CharField(max_length=32, blank=True, default="manual")

    objects = TenantScopedQuerySet.as_manager()

    class Meta:
        abstract = True
        indexes = [
            models.Index(fields=["tenant", "-created_at"]),
            models.Index(fields=["tenant", "is_deleted"]),
        ]