#coding=utf-8

import sys

import MySQLdb

class TransferMoney(object):

    def __init__(self,conn):

        self.conn = conn

    #检查账户是否合法

    def check_acct_avaiable(self,acctid):

        cursor = self.conn.cursor()

        try:

            sql = "select * from account where acctid=%s" % acctid

            cursor.execute(sql)

            print "check account:" + sql

            rs = cursor.fetchall()

            if len(rs) != 1:

                raise Exception("account %s illega" % acctid)

        finally:

            cursor.close()

    #检查是否有足够的钱

    def has_enough_money(self,acctid,money):

        cursor = self.conn.cursor()

        try:

            sql = "select * from account where acctid=%s and money > %s" % (acctid,money)

            cursor.execute(sql)

            print "has enough money:" + sql

            rs = cursor.fetchall()

            if len(rs) != 1:

                raise Exception("account %s not enough money" % acctid)

        finally:

            cursor.close()

    #账户减钱

    def reduce_money(self,acctid,money):

        cursor = self.conn.cursor()

        try:

            sql = "update account set money = money-%s where acctid = %s" % (money,acctid)

            cursor.execute(sql)

            print "reduce_money:" + sql

            if cursor.rowcount != 1:

                raise Exception("reduce money fail %s" % acctid)

        finally:

            cursor.close()

    #账户加钱

    def add_money(self,acctid,money):

        cursor = self.conn.cursor()

        try:

            sql = "update account set money = money+%s where acctid = %s" % (money,acctid)

            cursor.execute(sql)

            print "add_money:" + sql

            if cursor.rowcount != 1:

                raise Exception("add money fail %s" % acctid)

        finally:

            cursor.close()

    #主执行语句

    def transfer(self,source_acctid,target_acctid,money):

        try:

            self.check_acct_avaiable(source_acctid)

            self.check_acct_avaiable(target_acctid)

            self.has_enough_money(source_acctid,money)

            self.reduce_money(source_acctid,money)

            self.add_money(target_acctid,money)

            self.conn.commit()

        except Exception as e:

            self.conn.rollback()

            raise e

if __name__ == "__main__":

    source_acctid = sys.argv[1]

    target_acctid = sys.argv[2]

    money = sys.argv[3]

    conn = MySQLdb.Connect(host = '127.0.0.1',port=3306,user='root',passwd='',db='test',charset='utf8')

    tr_money = TransferMoney(conn)

    try:

        tr_money.transfer(source_acctid,target_acctid,money)

    except Exception as e:

        print "Happen:" + str(e)

    finally:

        conn.close()