# db_utils.py
import pyodbc
import config

def get_sql_conn():
    """获取 SQL Server 连接"""
    c = config.SQL_SERVER_CONN
    # 显式添加 TrustServerCertificate=yes 以兼容 ODBC Driver 18+
    conn_str = (
        f"DRIVER={c['driver']};SERVER={c['server']};"
        f"DATABASE={c['database']};UID={c['uid']};PWD={c['pwd']};"
        "Encrypt=yes;TrustServerCertificate=yes;" 
    )
    return pyodbc.connect(conn_str)

def get_access_conn(file_path):
    """获取 Access 连接"""
    conn_str = f"DRIVER={config.ACCESS_DRIVER};DBQ={file_path};"
    return pyodbc.connect(conn_str)

def fmt_table(schema, table):
    """格式化 SQL Server 表名 [schema].[table]"""
    return f"[{schema}].[{table}]"

def get_columns(cursor, table_name):
    """获取 Access 表的列名"""
    # Access 查询表名加 []
    cursor.execute(f"SELECT TOP 1 * FROM [{table_name}]")
    return [column[0] for column in cursor.description]

def generate_insert_sql(target_schema, target_table, columns):
    """生成带架构的 INSERT 语句"""
    full_table_name = fmt_table(target_schema, target_table)
    col_str = ",".join([f"[{col}]" for col in columns])
    placeholders = ",".join(["?"] * len(columns))
    return f"INSERT INTO {full_table_name} ({col_str}) VALUES ({placeholders})"