# -*- coding: utf-8 -*-

'''获取当前日期前后N天或N月的日期'''

from time import strftime, localtime
from datetime import timedelta, date
import calendar

year = strftime("%Y",localtime())
mon = strftime("%m",localtime())
day = strftime("%d",localtime())
hour = strftime("%H",localtime())
min = strftime("%M",localtime())
sec = strftime("%S",localtime())

def today():
 '''''
 get today,date format="YYYY-MM-DD"
 '''''
 return date.today()

def todaystr():
 '''
 get date string, date format="YYYYMMDD"
 '''
 return year+mon+day

def datetime():
 '''''
 get datetime,format="YYYY-MM-DD HH:MM:SS"
 '''
 return strftime("%Y-%m-%d %H:%M:%S",localtime())

def datetimestr():
 '''''
 get datetime string
 date format="YYYYMMDDHHMMSS"
 '''
 return year+mon+day+hour+min+sec

def get_day_of_day(n=0):
 '''''
 if n>=0,date is larger than today
 if n<0,date is less than today
 date format = "YYYY-MM-DD"
 '''
 if(n<0):
  n = abs(n)
  return date.today()-timedelta(days=n)
 else:
  return date.today()+timedelta(days=n)

def get_days_of_month(year,mon): 
 ''''' 
 get days of month 
 ''' 
 return calendar.monthrange(year, mon)[1] 
 
def get_firstday_of_month(year,mon): 
 ''''' 
 get the first day of month 
 date format = "YYYY-MM-DD" 
 ''' 
 days="01" 
 if(int(mon)<10): 
  mon = "0"+str(int(mon)) 
 arr = (year,mon,days) 
 return "-".join("%s" %i for i in arr) 
 
def get_lastday_of_month(year,mon): 
 ''''' 
 get the last day of month 
 date format = "YYYY-MM-DD" 
 ''' 
 days=calendar.monthrange(year, mon)[1] 
 mon = addzero(mon) 
 arr = (year,mon,days) 
 return "-".join("%s" %i for i in arr) 
 
def get_firstday_month(n=0): 
 ''''' 
 get the first day of month from today 
 n is how many months 
 ''' 
 (y,m,d) = getyearandmonth(n) 
 d = "01" 
 arr = (y,m,d) 
 return "-".join("%s" %i for i in arr) 
 
def get_lastday_month(n=0): 
 ''''' 
 get the last day of month from today 
 n is how many months 
 ''' 
 return "-".join("%s" %i for i in getyearandmonth(n)) 
 
def getyearandmonth(n=0): 
 ''''' 
 get the year,month,days from today 
 befor or after n months 
 ''' 
 thisyear = int(year) 
 thismon = int(mon) 
 totalmon = thismon+n 
 if(n>=0): 
  if(totalmon<=12): 
   days = str(get_days_of_month(thisyear,totalmon)) 
   totalmon = addzero(totalmon) 
   return (year,totalmon,days) 
  else: 
   i = totalmon/12 
   j = totalmon%12 
   if(j==0): 
    i-=1 
    j=12 
   thisyear += i 
   days = str(get_days_of_month(thisyear,j)) 
   j = addzero(j) 
   return (str(thisyear),str(j),days) 
 else: 
  if((totalmon>0) and (totalmon<12)): 
   days = str(get_days_of_month(thisyear,totalmon)) 
   totalmon = addzero(totalmon) 
   return (year,totalmon,days) 
  else: 
   i = totalmon/12 
   j = totalmon%12 
   if(j==0): 
    i-=1 
    j=12 
   thisyear +=i 
   days = str(get_days_of_month(thisyear,j)) 
   j = addzero(j) 
   return (str(thisyear),str(j),days) 
 
def addzero(n): 
 ''''' 
 add 0 before 0-9 
 return 01-09 
 ''' 
 nabs = abs(int(n)) 
 if(nabs<10): 
  return "0"+str(nabs) 
 else: 
  return nabs 

def get_today_month(n=0): 
 ''''' 
 获取当前日期前后N月的日期
 if n>0, 获取当前日期前N月的日期
 if n<0, 获取当前日期后N月的日期
 date format = "YYYY-MM-DD" 
 ''' 
 (y,m,d) = getyearandmonth(n) 
 arr=(y,m,d) 
 if(int(day)<int(d)): 
  arr = (y,m,day) 
 return "-".join("%s" %i for i in arr) 
 

if __name__=="__main__":
 print today() 
 print todaystr()
 print datetime()
 print datetimestr()
 print get_day_of_day(20)
 print get_day_of_day(-3)
 print get_today_month(-3)
 print get_today_month(3)