# -*- coding: utf-8 -*-
"""
基础模型模块
提供跨数据库兼容的基础模型类和类型装饰器
"""

from datetime import datetime
from typing import Optional
from sqlalchemy import Integer, DateTime, Text
from sqlalchemy.ext.asyncio import AsyncAttrs
from sqlalchemy.orm import relationship, DeclarativeBase, Mapped, declared_attr, mapped_column


class MappedBase(AsyncAttrs, DeclarativeBase):
    """
    声明式基类

    `AsyncAttrs <https://docs.sqlalchemy.org/en/20/orm/extensions/asyncio.html#sqlalchemy.ext.asyncio.AsyncAttrs>`__

    `DeclarativeBase <https://docs.sqlalchemy.org/en/20/orm/declarative_config.html>`__

    `mapped_column() <https://docs.sqlalchemy.org/en/20/orm/mapping_api.html#sqlalchemy.orm.mapped_column>`__

    兼容 SQLite、MySQL 和 PostgreSQL
    """

    __abstract__ = True

    @declared_attr.directive
    def __tablename__(cls) -> str:
        """生成表名"""
        return cls.__name__.lower()

    @declared_attr.directive
    def __table_args__(cls) -> dict:
        """表配置"""
        return {'comment': cls.__doc__ or ''}


class ModelMixin(MappedBase):
    """
    基础模型混合类
    """
    __abstract__ = True

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True, comment='主键ID')
    description: Mapped[Optional[str]] = mapped_column(Text, nullable=True, default=None, comment="备注/描述")
    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, nullable=True, default=datetime.now, comment='创建时间')
    updated_at: Mapped[Optional[datetime]] = mapped_column(DateTime, nullable=True, default=datetime.now, onupdate=datetime.now, comment='更新时间')


class CreatorMixin(ModelMixin):
    """
    创建人混合类
    """
    __abstract__ = True

    creator_id: Mapped[Optional[int]] = mapped_column(Integer, nullable=True, index=True, comment="创建人ID")

    @declared_attr
    def creator(cls) -> Mapped[Optional["UserModel"]]:  # type: ignore
        """创建人关联关系（延迟加载，避免循环依赖）"""
        return relationship(
            "UserModel",
            primaryjoin=f"{cls.__name__}.creator_id == UserModel.id",
            lazy="selectin",
            foreign_keys=lambda: [cls.creator_id],  # type: ignore
            viewonly=True,
            uselist=False  # 明确指定返回单个对象
        )