#!/usr/bin/env python
# -*- encoding: utf8 -*-
import calendar
import time
import os
import sys
from datetime import datetime,timedelta
import mysql.connector

# 定义一些全局变量
work_dir = "G:"
#argv_database_name=sys.argv[1]
#argv_table_name=sys.argv[2]

getdbconfig_0_152 = {
    'host': '127.0.0.1',
    'user': 'root',
    'password': 'root',
    'port': '3306',
    'database': 'partition_test'
}

# 此函数用来打印输出制定内容，第一个变量是输出内容，第二个变量是文件前缀，第三个变量是后缀名
def print_log(print_content,filename,suffix):
    my_log_day = time.strftime("%Y%m%d")
    my_log_file="%s%s_%s.%s" %(work_dir,filename,my_log_day,suffix)
    #with open(my_log_file, "aw") as f:
    with open(my_log_file, "a") as f:
        f.write( print_content+"\n")
        f.close()

# 此函数用来指定某个月增加一个月
def add_month(srcDate, addMonths):
    if not srcDate or not srcDate:
        pass
    if addMonths < 1:
        return srcDate
    month = srcDate.month - 1 + addMonths
    year = srcDate.year + month / 12
    month = month % 12 + 1
    day = min(srcDate.day, calendar.monthrange(year, month)[1])
    return srcDate.replace(year=year, month=month, day=day)


def select_any_sql(getdbconfig,select_sql):
    select_any_sql_cnn = mysql.connector.connect(host=getdbconfig['host'], db=getdbconfig['database'], user=getdbconfig['user'], password=getdbconfig['password'],port=getdbconfig['port'])
    select_any_sql_cursor = select_any_sql_cnn.cursor()
    select_any_sql_cursor.execute(select_sql)
    select_any_sql_data = select_any_sql_cursor.fetchone()
    return select_any_sql_data

def select_partition(getdbconfig):
    select_partition_sql = "SELECT table_schema,table_name,PARTITION_NAME,PARTITION_ORDINAL_POSITION,PARTITION_METHOD,PARTITION_EXPRESSION,PARTITION_DESCRIPTION FROM information_schema.`PARTITIONS` " \
                           "WHERE table_schema not in ('information_schema','performance_schema','mysql','test','sqlexe') and PARTITION_NAME is not null order by table_schema,PARTITION_NAME, PARTITION_ORDINAL_POSITION;"
    partition_contain_before = ()
    partition_info = []
    cnn = mysql.connector.connect(**getdbconfig)
    cursor = cnn.cursor()
    cursor.execute(select_partition_sql)
    for (table_schema, table_name, PARTITION_NAME, PARTITION_ORDINAL_POSITION, PARTITION_METHOD, PARTITION_EXPRESSION,
         PARTITION_DESCRIPTION) in cursor:
        PARTITION_ORDINAL_POSITION_NUM = int(PARTITION_ORDINAL_POSITION) - 1
        if PARTITION_DESCRIPTION == 'MAXVALUE':
            select_paritition_description_sql = "SELECT PARTITION_NAME AS PARTITION_NAME_BEFORE,PARTITION_DESCRIPTION AS PARTITION_DESCRIPTION_BEFORE FROM information_schema.`PARTITIONS` " \
                                                "WHERE table_schema='%s' and table_name='%s'  and PARTITION_ORDINAL_POSITION='%s' ;" % (table_schema, table_name, PARTITION_ORDINAL_POSITION_NUM)
            mysql_select_cnn = mysql.connector.connect(**getdbconfig)
            mysql_select_cursor = mysql_select_cnn.cursor()
            mysql_select_cursor.execute(select_paritition_description_sql)
            for (PARTITION_NAME_BEFORE, PARTITION_DESCRIPTION_BEFORE) in mysql_select_cursor:
                partition_contain_before = (table_schema, table_name, PARTITION_NAME, PARTITION_NAME_BEFORE, PARTITION_METHOD,PARTITION_DESCRIPTION, PARTITION_DESCRIPTION_BEFORE)
                partition_info.append(partition_contain_before)
    if len(partition_info) == 0:
        print "PARTITION in the Database does not exist!!!"
    else:
        for i in partition_info:
            print "database:", i[0]
            if i[4] == 'RANGE':
                # 此部分数据用于生成alter table drop 语句  alter table t_lgj_log add PARTITION(PARTITION p201804 VALUES LESS THAN (737150));
                select_max_partition_name_sql = "select count(*) as COUNT from %s.%s partition(%s)" % (i[0], i[1], i[2])
                max_partition_name_count = select_any_sql(getdbconfig, select_max_partition_name_sql)[0]
                if max_partition_name_count==0:
                    prompt_database="-- database : %s" %(i[0])
                    print_log(prompt_database, "auto_create_partition", "sql")
                    print_user_database="use %s;" %(i[0])
                    print_log(print_user_database, "auto_create_partition", "sql")
                    sql_alter_table_drop_partition = "alter table %s.%s drop PARTITION  %s;" % (i[0], i[1], i[2])
                    # auto_create_partition 指的是用于自动删除最大分区并添加分区的脚本
                    print_log(sql_alter_table_drop_partition, "auto_create_partition", "sql")
                else:
                    return_info_can_not_drop_max_partition = "%s.%s.%s" % (i[0], i[1], i[2])
                    # can_not_drop_max_partition 指的是最大分区中有数据，然后这部分数据并不能直接删除，把这些分区信息记录下来
                    print_log(return_info_can_not_drop_max_partition, "can_not_drop_max_partition", "sql")

                # 此部分数据用于生成alter table add 语句  alter table t_lgj_log add PARTITION(PARTITION p201804 VALUES LESS THAN (737150));
                select_next_paritition_description_name="select from_days(%s);" %(i[6])
                maxvalue_date=add_month(select_any_sql(getdbconfig, select_next_paritition_description_name)[0],1).strftime('%Y-%m-%d')
                maxvalue_date_year_month=add_month(select_any_sql(getdbconfig, select_next_paritition_description_name)[0],1).strftime('%Y%m')
                add_partition_name_01="p%s" %(maxvalue_date_year_month)
                # 此部分用于判断生成的 PARTITION_NAME 是否已经存在，如果存在，则需要在月份上加1
                if add_partition_name_01 == i[3]:
                    add_partition_name=add_partition_name_01
                else:
                    maxvalue_date_year_month_01=add_month(add_month(select_any_sql(getdbconfig, select_next_paritition_description_name)[0],1),1).strftime('%Y%m')
                    add_partition_name = "p%s" % (maxvalue_date_year_month_01)
                less_than_sql="select to_days('%s')" %(maxvalue_date)
                less_than_name=select_any_sql(getdbconfig,less_than_sql)[0]
                sql_alter_table_add_partition="alter table %s.%s add  PARTITION(PARTITION  %s VALUES LESS THAN (%s));" %(i[0], i[1],add_partition_name,less_than_name)
                print_log(sql_alter_table_add_partition, "auto_create_partition", "sql")
            else:
                # can_not_drop_max_partition 指的是分区规则并不是range分区，把这些分区信息记录下来
                print_log(i, "partition_info_not_in_range", "sql")
    print "Done!!!"

select_partition(getdbconfig_0_152)