"""迁移脚本：添加 baodan_conversation_id 字段到会话表。"""
import logging
from insurance.db.compat import db


def migrate():
    """添加 baodan_conversation_id 字段到 insurance_chat_sessions 表。"""
    try:
        from sqlalchemy import inspect

        # 检查字段是否已存在
        inspector = inspect(db.engine)
        columns = [col['name'] for col in inspector.get_columns('insurance_chat_sessions')]
        if 'baodan_conversation_id' in columns:
            logging.info("字段 baodan_conversation_id 已存在，跳过添加")
            return

        # 根据数据库方言执行不同的 SQL
        dialect = db.engine.dialect.name
        if dialect == 'sqlite':
            # SQLite 不支持 COMMENT 语法
            db.session.execute(
                "ALTER TABLE insurance_chat_sessions "
                "ADD COLUMN baodan_conversation_id VARCHAR(128)"
            )
        else:
            # PostgreSQL
            db.session.execute(
                "ALTER TABLE insurance_chat_sessions "
                "ADD COLUMN baodan_conversation_id VARCHAR(128) NULL "
                "COMMENT 'BaoDan 返回的 conversation_id，用于保持上下文'"
            )

        db.session.commit()
        logging.info("成功添加 baodan_conversation_id 字段")

    except Exception as e:
        logging.error(f"添加字段失败: {e}")
        db.session.rollback()
        raise


def downgrade():
    """删除 baodan_conversation_id 字段。"""
    try:
        from sqlalchemy import inspect

        inspector = inspect(db.engine)
        columns = [col['name'] for col in inspector.get_columns('insurance_chat_sessions')]
        if 'baodan_conversation_id' not in columns:
            logging.info("字段 baodan_conversation_id 不存在，跳过删除")
            return

        db.session.execute(
            "ALTER TABLE insurance_chat_sessions DROP COLUMN baodan_conversation_id"
        )
        db.session.commit()
        logging.info("成功删除 baodan_conversation_id 字段")

    except Exception as e:
        logging.error(f"删除字段失败: {e}")
        db.session.rollback()
        raise


if __name__ == "__main__":
    # 直接运行迁移
    import sys
    sys.path.insert(0, ".")
    from app import app
    with app.app_context():
        migrate()
        print("迁移完成")