from sqlalchemy import Column, Integer, Float, DateTime, func
from app.database import Base


class LineState(Base):
    """产线运行状态单例（id=1），用于停机自动检测。"""
    __tablename__ = "line_state"

    id = Column(Integer, primary_key=True, index=True)
    speed = Column(Float, default=0, comment="当前线速度 m/min")
    zero_since = Column(DateTime, comment="速度为0的起始时间")
    open_downtime_id = Column(Integer, comment="当前未结束的自动停机记录id")
    updated_at = Column(DateTime, server_default=func.now(), onupdate=func.now())
