"""Schema 版本历史模型。"""
from sqlalchemy import Column, Integer, String, Text, DateTime, ForeignKey, func

from app.core.database import Base


class SchemaRevision(Base):
    """Schema 版本历史（Schema-as-Code）。"""
    __tablename__ = "schema_revisions"

    id = Column(Integer, primary_key=True, autoincrement=True)
    instance_id = Column(Integer, ForeignKey("instances.id"), nullable=False)
    database = Column(String(100), nullable=False)
    revision = Column(String(64), nullable=False)
    ddl_content = Column(Text, nullable=True)
    checksum = Column(String(64), nullable=False)
    applied_by = Column(Integer, ForeignKey("users.id"), nullable=True)
    applied_at = Column(DateTime, server_default=func.now())
    status = Column(String(20), default="applied")