"""基础模型"""
from datetime import datetime
from sqlmodel import SQLModel, Field
from uuid import uuid4


def generate_uuid() -> str:
    """生成 UUID"""
    return str(uuid4())


class TimestampModel(SQLModel):
    """时间戳 Mixin"""
    created_at: datetime = Field(
        default_factory=datetime.utcnow,
        nullable=False,
        sa_column_kwargs={"index": True},
    )
    updated_at: datetime = Field(
        default_factory=datetime.utcnow,
        nullable=False,
        sa_column_kwargs={"onupdate": datetime.utcnow},
    )