"""
使用DBUtils数据库连接池中的连接，操作数据库
OperationalError: (2006, ‘MySQL server has gone away’)
"""
import datetime
import json

import pymysql
from dbutils.pooled_db import PooledDB


class MysqlClient(object):
    __pool = None

    def __init__(self, mincached=10, maxcached=20, maxshared=10, maxconnections=200, blocking=True,
                 maxusage=100, setsession=None, reset=True,
                 host="10.10.14.199", port=22066, db="dsideal_db",
                 user="root", passwd="DsideaL147258369", charset='utf8mb4'):
        """
        :param mincached:连接池中空闲连接的初始数量
        :param maxcached:连接池中空闲连接的最大数量
        :param maxshared:共享连接的最大数量
        :param maxconnections:创建连接池的最大数量
        :param blocking:超过最大连接数量时候的表现，为True等待连接数量下降，为false直接报错处理
        :param maxusage:单个连接的最大重复使用次数
        :param setsession:optional list of SQL commands that may serve to prepare
            the session, e.g. ["set datestyle to ...", "set time zone ..."]
        :param reset:how connections should be reset when returned to the pool
            (False or None to rollback transcations started with begin(),
            True to always issue a rollback for safety's sake)
        :param host:数据库ip地址
        :param port:数据库端口
        :param db:库名
        :param user:用户名
        :param passwd:密码
        :param charset:字符编码
        """

        if not self.__pool:
            self.__class__.__pool = PooledDB(pymysql,
                                             mincached, maxcached,
                                             maxshared, maxconnections, blocking,
                                             maxusage, setsession, reset,
                                             host=host, port=port, db=db,
                                             user=user, passwd=passwd,
                                             charset=charset,
                                             cursorclass=pymysql.cursors.DictCursor
                                             )
        self._conn = None
        self._cursor = None
        self.__get_conn()

    def __get_conn(self):
        self._conn = self.__pool.connection();
        self._cursor = self._conn.cursor();

    def close(self):
        try:
            self._cursor.close()
            self._conn.close()
        except Exception as e:
            print(e)

    def __execute(self, sql, param=()):
        count = self._cursor.execute(sql, param)
        # print(count)
        self._conn.commit()
        return count

    @staticmethod
    def __dict_datetime_obj_to_str(result_dict):
        """把字典里面的datatime对象转成字符串，使json转换不出错"""
        if result_dict:
            result_replace = {k: v.__str__() for k, v in result_dict.items() if isinstance(v, datetime.datetime)}
            result_dict.update(result_replace)
        return result_dict

    def find(self, sql, param=()):
        """查询单个结果"""
        count = self.__execute(sql, param)
        result = self._cursor.fetchone()
        """:type result:dict"""
        result = self.__dict_datetime_obj_to_str(result)
        return count, result

    def findList(self, sql, param=()):
        """
        查询多个结果
        :param sql: qsl语句
        :param param: sql参数
        :return: 结果数量和查询结果集
        """
        count = self.__execute(sql, param)
        result = self._cursor.fetchall()
        """:type result:list"""
        [self.__dict_datetime_obj_to_str(row_dict) for row_dict in result]
        return count, result

    def execute(self, sql, param=()):
        count = self.__execute(sql, param)
        return count

    def begin(self):
        """开启事务"""
        self._conn.autocommit(0)

    def end(self, option='commit'):
        """结束事务"""
        if option == 'commit':
            self._conn.autocommit()
        else:
            self._conn.rollback()


if __name__ == "__main__":

    # 调用示例
    db = MysqlClient()
    sql1 = 'SELECT * FROM t_sys_loginperson  limit 1'
    result1 = db.find(sql1)
    print(json.dumps(result1[1], ensure_ascii=False))

    sql2 = 'SELECT * FROM t_cdwl_subject  WHERE  subject_id IN (%s,%s,%s)'
    param = (6, 8, 9)

    sql = 'select resource_type_name,c from t_huanghai_pie'
    l1 = db.findList(sql)
    keys = []
    values = []
    for i in range(0, l1[0]):
        keys.append(l1[1][i]['resource_type_name'])
        values.append(l1[1][i]['c'])

    # print(json.dumps(db.findList(sql2, param)[1], ensure_ascii=False))