"""模型基类

包含时间戳 Mixin 和通用基类
遵循瑞小美数据库设计规范
"""

from datetime import datetime

from sqlalchemy import BigInteger, Integer, DateTime, func
from sqlalchemy.orm import Mapped, mapped_column

from app.database import Base
from app.config import settings


# 主键类型：SQLite 使用 Integer（支持自增），MySQL 使用 BigInteger
# SQLite 的 AUTOINCREMENT 只在 INTEGER PRIMARY KEY 时生效
_PrimaryKeyType = Integer if settings.DATABASE_URL.startswith("sqlite") else BigInteger


class TimestampMixin:
    """时间戳 Mixin"""
    
    created_at: Mapped[datetime] = mapped_column(
        DateTime,
        nullable=False,
        default=func.now(),
        server_default=func.now(),
        comment="创建时间"
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime,
        nullable=False,
        default=func.now(),
        server_default=func.now(),
        onupdate=func.now(),
        comment="更新时间"
    )


class BaseModel(Base, TimestampMixin):
    """模型基类"""
    
    __abstract__ = True
    
    id: Mapped[int] = mapped_column(
        _PrimaryKeyType,
        primary_key=True,
        autoincrement=True,
        comment="主键ID"
    )