#!/usr/bin/python

import os
import sys
import datetime
from datetime import datetime, timedelta

import glob
import string

import smtplib
import email

#basic config - please do not change
HOSTNAME = os.uname()[1]
LOCKDIR = "/tmp/rn-innobackup.lock" #LOCKDIR
LOGFILE = "/var/log/rn-mysqlbackup.log" #LOGFILE
INNOBACKUPEX = "/usr/bin/innobackupex"
ALERTMAIL = "mmaros@reflected.net" #to use multiple recepients, this needs to be turned into a list ["email1@bla.com", "email2@bla.com", "email3@bla.com", ...]
#ALERTMAIL = "support@reflected.net" #to use multiple recepients, this needs to be turned into a list ["email1@bla.com", "email2@bla.com", "email3@bla.com", ...]


#backup configuration
#to use one binary over other, please put it at the start of the list, if it doesnt exist it will get skipped
COMPRESS = ["/usr/bin/pbzip2","/usr/local/sbin/pbzip2","/usr/bin/pigz","/usr/local/sbin/pigz"]
BACKUPDIR = '/home/backups/mysql/'
RETENTION  =int(7)
STREAMING = False
PARALEL = int(4)
USEMEMORY = "1G"
CUSTOMOPT = "" #separate them with a space between, use syntax same as on the cli "--option=value --option2=value
DATADIR = '/home/mysql/data'


########Bunch of checks that need to be ran before we proceed
########
#check which compression to use
compression = ""
for i in range(0, len(COMPRESS)):
    if os.path.isfile(COMPRESS[i]):
        compression = COMPRESS[i]
        break
#exit if compression is not set up
if compression == "":
    print ("none of compressions are available, please check which ones are available and which ones are provided")
    sys.exit()
#exit if datadir doesnt exist
if os.path.isdir(DATADIR) is False:
    print (DATADIR + "does not exit")
    sys.exit()

#compression being used:
if ("pbzip2" in compression):
    backupSuffix = ".tar.bz2"
elif ("pigz" in compression):
    backupSuffix = ".tar.gz"
else:
    print ("wrong  compression")
    sys.exit()
curDate = ""

#skip disk check if .skipcheck is present in backupdir, remove after the run
def skipCheck():
    if os.path.isfile(BACKUPDIR + ".skipcheck"):
        now = datetime.today().strftime("%Y-%m-%d %H:%M:%S")
        print(now + ": Skipping prerun disk space checks and running backups. skipcheck file will be removed")
        #function that runs backups
        os.remove(BACKUPDIR + ".skipcheck")
    else:
        isRunnable()

#check total freeDisk disk space on partition containting BACKUPDIR, in bytes
def freeSpace(BACKUPDIR):
    st = os.statvfs(BACKUPDIR)
    freeDisk = int(st.f_bavail * st.f_frsize)
    return freeDisk

#get the size of the backup specified
def lastBackup(BACKUPDIR, backupSuffix, oldDate):
    if STREAMING:
        backupName = os.path.join(BACKUPDIR + 'mysql_backups_' + HOSTNAME + '_' + '*-streaming' + backupSuffix)
    else:
        backupName = os.path.join(BACKUPDIR + 'mysql_backups_' + HOSTNAME + '_' + '*' + backupSuffix)
    print (backupName)
    lastSize = os.path.getsize(max(glob.iglob(backupName) , key = os.path.getctime))
    print (lastSize)
    return lastSize

#get current date in "20180409"/"YYYYMMDD" format, minus N days
def curDate(oldAge):
    curDate = datetime.today() - timedelta(days=oldAge)
    curDate = curDate.strftime("%Y%m%d")
    return curDate;

#get size of the mysql datadir
def dirSize(path):
    total_size = 0
    for dirpath, dirnames, filenames in os.walk(path):
        for f in filenames:
            fp = os.path.join(dirpath, f)
            total_size += os.path.getsize(fp)
    return total_size

#prerun checks
def isRunnable():
    oldAge = 1
    oldDate = curDate(oldAge)
    lastSize = lastBackup(BACKUPDIR , backupSuffix, oldDate)
    freeDisk = freeSpace(BACKUPDIR)
    #if streaming backup, we dont care about size of the datadir
    if STREAMING:
        datadirSize = 0
    else:
        datadirSize = dirSize(DATADIR)
    print("Size of last backup")
    print(lastSize)
    print("Free disk size")
    print(freeDisk)
    print("Datadir size")
    print(datadirSize)
    if ((freeDisk - lastSize - datadirSize) * 1.05) < (lastSize + datadirSize):
        msgBody = "Cant run backups as there is not enough free disk space"
        sendMail(msgBody)
    print ("All gucci")

#sendmail and exit function
def sendMail(msgBody):
    sender = 'root@' + HOSTNAME + '.ded.reflected.net'
    receivers = ALERTMAIL
    msgBody = msgBody

    #print ("this works")
    #message = """From: """ + sender + """\nTo: """ + receivers + """\nSubject: backup failed on """ + HOSTNAME + """\n\n""" + msgBody + """\n"""

    #its still ugly, but ugly in mutliple lines
    message = ("From: " + sender + "\n"
    "To:" + receivers + "\n"
    "Subject: Backup failed on " + HOSTNAME + "\n\n"
    + msgBody + "\n")

    #smtpObj = smtplib.SMTP('smtp-out.reflected.net')
    #smtpObj.sendmail(sender, receivers, message)
    print ("Successfully sent email")
    sys.exit()


skipCheck()