import pymysql
from pymysql import Error
from typing import List, Dict, Union, Optional, Tuple

class MySQLHelper:
    def __init__(self, host: str, user: str, password: str, database: str, 
                 port: int = 3306, charset: str = 'utf8mb4'):
        """
        初始化MySQL连接参数
        :param host: 数据库地址
        :param user: 用户名
        :param password: 密码
        :param database: 数据库名
        :param port: 端口，默认3306
        :param charset: 字符集，默认utf8mb4
        """
        self.host = host
        self.user = user
        self.password = password
        self.database = database
        self.port = port
        self.charset = charset
        self.connection = None
        self.cursor = None

    def connect(self) -> bool:
        """
        连接到MySQL数据库
        :return: 连接成功返回True，失败返回False
        """
        try:
            self.connection = pymysql.connect(
                host=self.host,
                user=self.user,
                password=self.password,
                database=self.database,
                port=self.port,
                charset=self.charset,
                cursorclass=pymysql.cursors.DictCursor  # 返回字典形式的结果
            )
            self.cursor = self.connection.cursor()
            print("MySQL数据库连接成功")
            return True
        except Error as e:
            print(f"连接MySQL数据库失败: {e}")
            return False

    def close(self) -> None:
        """
        关闭数据库连接
        """
        if self.cursor:
            self.cursor.close()
        if self.connection:
            self.connection.close()
        print("MySQL数据库连接已关闭")

    def execute_query(self, sql: str, params: Union[Tuple, List, Dict, None] = None) -> List[Dict]:
        """
        执行查询操作
        :param sql: SQL语句
        :param params: 参数，可以是元组、列表或字典
        :return: 查询结果列表
        """
        try:
            self.cursor.execute(sql, params)
            return self.cursor.fetchall()
        except Error as e:
            print(f"查询执行失败: {e}")
            return []

    def execute_update(self, sql: str, params: Union[Tuple, List, Dict, None] = None) -> int:
        """
        执行更新操作（INSERT/UPDATE/DELETE）
        :param sql: SQL语句
        :param params: 参数，可以是元组、列表或字典
        :return: 影响的行数
        """
        try:
            affected_rows = self.cursor.execute(sql, params)
            self.connection.commit()
            return affected_rows
        except Error as e:
            self.connection.rollback()
            print(f"更新执行失败: {e}")
            return 0

    def execute_many(self, sql: str, params_list: List[Union[Tuple, List, Dict]]) -> int:
        """
        批量执行操作
        :param sql: SQL语句
        :param params_list: 参数列表
        :return: 影响的行数
        """
        try:
            affected_rows = self.cursor.executemany(sql, params_list)
            self.connection.commit()
            return affected_rows
        except Error as e:
            self.connection.rollback()
            print(f"批量执行失败: {e}")
            return 0

    def get_one(self, sql: str, params: Union[Tuple, List, Dict, None] = None) -> Optional[Dict]:
        """
        获取单条记录
        :param sql: SQL语句
        :param params: 参数，可以是元组、列表或字典
        :return: 单条记录或None
        """
        try:
            self.cursor.execute(sql, params)
            return self.cursor.fetchone()
        except Error as e:
            print(f"获取单条记录失败: {e}")
            return None

    def table_exists(self, table_name: str) -> bool:
        """
        检查表是否存在
        :param table_name: 表名
        :return: 存在返回True，否则返回False
        """
        sql = "SHOW TABLES LIKE %s"
        result = self.execute_query(sql, (table_name,))
        return len(result) > 0

    def __enter__(self):
        """支持with上下文管理"""
        self.connect()
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        """支持with上下文管理"""
        self.close()