"""迁移 025: PPT 会话表新增预览与质量检查字段。"""
import logging

from sqlalchemy import text

logger = logging.getLogger(__name__)


def migrate():
    """为 insurance_ppt_sessions 表添加预览相关字段。"""
    from insurance.db.compat import db

    columns = {
        "slides_json_path": "VARCHAR(500) DEFAULT NULL",
        "quality_report_json": "TEXT DEFAULT NULL",
        "preview_status": "VARCHAR(20) NOT NULL DEFAULT 'none'",
        "deck_contract_path": "VARCHAR(500) DEFAULT NULL",
        "versions_json": "TEXT DEFAULT NULL",
    }

    for col_name, col_def in columns.items():
        exists = db.session.execute(text(
            "SELECT COUNT(*) FROM information_schema.columns "
            "WHERE table_name = 'insurance_ppt_sessions' AND column_name = :col"
        ), {"col": col_name}).scalar()
        if not exists:
            db.session.execute(text(
                f"ALTER TABLE insurance_ppt_sessions ADD COLUMN {col_name} {col_def}"
            ))
            logger.info("[migrate_025] 已添加字段 %s", col_name)
        else:
            logger.info("[migrate_025] 字段 %s 已存在，跳过", col_name)

    db.session.commit()
    logger.info("[migrate_025] 迁移完成")