import sqlite3
from db_utils import get_db_connection, close_db_connection


def remove_department_from_query_history():
    """
    从query_history表中删除department字段
    SQLite不支持直接删除列，采用以下步骤：
    1. 创建一个不包含department字段的新表
    2. 将原始表中的数据（除department外）复制到新表
    3. 删除原始表
    4. 重命名新表为原始表名
    5. 重新创建索引和外键约束
    """
    conn = None
    try:
        # 获取数据库连接
        conn = get_db_connection()
        cursor = conn.cursor()
        
        print("开始从query_history表中删除department字段...")
        
        # 1. 创建临时表，不包含department字段
        print("1. 创建临时表query_history_new...")
        cursor.execute('''
            CREATE TABLE IF NOT EXISTS query_history_new (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                query_date TEXT NOT NULL,
                plate_number TEXT,
                phone TEXT,
                results_count INTEGER NOT NULL,
                query_ip TEXT NOT NULL,
                user_id INTEGER,
                FOREIGN KEY (user_id) REFERENCES users (id)
            )
        ''')
        
        # 2. 复制数据到新表，排除department字段
        print("2. 复制数据到新表，排除department字段...")
        cursor.execute('''
            INSERT INTO query_history_new (id, query_date, plate_number, phone, results_count, query_ip, user_id)
            SELECT id, query_date, plate_number, phone, results_count, query_ip, user_id
            FROM query_history
        ''')
        
        # 3. 删除原表
        print("3. 删除原始表query_history...")
        cursor.execute('DROP TABLE IF EXISTS query_history')
        
        # 4. 重命名新表为原表名
        print("4. 重命名新表为query_history...")
        cursor.execute('ALTER TABLE query_history_new RENAME TO query_history')
        
        # 5. 提交事务
        conn.commit()
        print("操作完成：department字段已成功从query_history表中删除！")
        
    except sqlite3.Error as e:
        print(f"数据库操作出错：{e}")
        if conn:
            conn.rollback()
        raise
    finally:
        if conn:
            close_db_connection(conn)


if __name__ == "__main__":
    remove_department_from_query_history()