# -*- coding: utf-8 -*-
"""
MySQL客户端模块
"""

from urllib.parse import quote_plus

import pandas
from sqlalchemy import create_engine, text


class MySQL:
    """
    MySQL客户端
    """

    def __init__(
        self,
        database: str,
        host: str = "cdb-7z9lzx4y.cd.tencentcdb.com",  # 默认为刘弼仁的腾讯云MySQL数据库
        port: int = 10039,
        username: str = "root",
        password: str = "Te198752",
    ) -> None:
        """
        初始化
        :param database: 数据库名称
        :param host: 主机
        :param port: 端口
        :param username: 用户名
        :param password: 登录密码
        """
        # 就登录密码编码
        password = quote_plus(password)
        # 构建数据库连接
        connection_url = f"mysql+pymysql://{username}:{password}@{host}:{port}/{database}?charset=utf8"

        # 创建MySQL引擎并连接数据库
        self.engine = create_engine(
            connection_url,
            pool_size=5,
            max_overflow=10,
            pool_recycle=3600,
            pool_pre_ping=True,
        )  # 连接池中保持打开连接的数量为5，额外连接数为10，连接1小时后重新回收重连，检查连接有效性

    def execute_query(self, sql: str) -> pandas.DataFrame:
        """执行SQL查询并返回DATAFRAME"""

        if not hasattr(self, "engine") or not self.engine:
            raise ConnectionError("未创建数据库连接")

        try:
            with self.engine.connect() as connection:
                dataframe = pandas.read_sql_query(
                    text(sql), connection, coerce_float=False
                )  # 不尝试将非整数数值转为浮点（维持DECIMAL）
            return dataframe

        except:
            connection.rollback()
            raise RuntimeError("执行SQL查询并返回DATAFRAME发生其它异常")

    def __del__(self):
        """析构时自动关闭连接"""

        if hasattr(self, "engine") and self.engine:
            self.engine.dispose()